07-17
2021
The meaning of circuit simulation is to simulate the designed circuit diagram through circuit simulation software to simulate the actual function, and then analyze and improve it to realize the optimal design of the circuit. In fact, the circuit simulation software we use is based on the subject of circuits, and it is an extended software that helps us better learn digital electronics and analog electronics. The key link to realize the design is the simulation process, which is used to judge whether the designer's thinking is correct or not, which is convenient for us to modify, saves a lot of experimental materials, and is more suitable for future development trends. The circuit simulation software we use now is approaching a mature stage, but the development process is long and arduous. So what is the real history of circuit simulation software? What is the reason for its rapid development? And what is the current situation of the circuit simulation software we commonly use now? In this article will introduce one by one.1. The concept and field of simulation softwareSimulation software is a computer software used for simulation. It is a tool for emulation, similar to emulating hardware. Simulation software has been continuously evolving since the mid-1950s. Its development complements the application of simulation, algorithms, computation and modeling, and other technological developments. [1] In 1984, the first database center simulation software appeared, and an artificial intelligence software system (expert system) appeared. This development trend will make simulation software more powerful, more flexible, and available to more users.The goal of the simulation is to continuously improve the descriptive capabilities of the navigation module for user orientation and model testing. Users of different technical levels can use their customized language through the simulation software to facilitate dialogue with the computer to complete simulation testing and modeling. Simulation is the experimental process of studying real systems by establishing real system models and using observable models. Initially, simulation technology was mainly used in aviation, aerospace, nuclear energy and expensive nuclear reactors, or some test systems with long life cycle and high risk, which were difficult to realize in other physical fields. Electricity, petroleum, chemical industry, metallurgy, machinery, etc. have gradually developed, and have been further expanded to non-technical systems such as social systems, economic systems, transportation systems, and ecological systems. It can be said that modern simulation technology and simulation system have become the integration of any complex system, especially in the high-tech industry is an important means of non-analysis. Lack of research, design, evaluation, decision-making and training. Its scope of application continues to expand, and its application efficiency is becoming more and more significant. The system is based on the simulation control theory, uses basic computer information processing technology, theoretical basis, computer and other equipment as special tools, uses the actual or virtual model of the system to test the system, and relies on experts to apply experimental knowledge, statistical data and information data to analyze the results . And give a comprehensive test decision. [3] Broadly speaking, the simulation system method is applicable to any field, including electrical, chemical, electronic, mechanical, etc., as well as economics, politics, transportation, management, etc.2. The reasons for the rapid development of simulation softwareWhy is the development of circuit simulation software so fast? The main reason is that computer simulation has the characteristics of high efficiency, high precision, high reliability, and low cost, and is widely used in the analysis and design of power electronic circuits (or systems). In addition to computer simulation, it is also necessary to reduce labor intensity to replace many cumbersome manual analysis systems, improve analysis and design capabilities, avoid large errors caused by analysis methods in the approximation process, and reduce the maximum design cost and shorten the system time through complementary trials. Development cycle. Computer simulation technology has greatly accelerated the process of circuit design and experimentation.Simulation is an effective means of designing circuits and systems. The main function of electrical engineering circuits and their constituent systems is to control energy conversion and transmission processes. The form of electricity needs to change, and the control method depends on electronic circuits. The combination of electricity and electronics forms the subject of power electronics, a relatively young field that is also a fringe field that combines multiple sciences. Electronic control circuit, large power energy, large inertia, very fast speed. These two systems, especially when they constitute a closed-loop system, are ill-conditioned systems in terms of automatic control, which means that there are stability problems that are not easy to solve. The quality of this type of system improved rapidly in the late 1980s due to the use of computer simulations. This problem is solved by choosing the appropriate circuit design software when using a computer for simulation. A small number of software mostly solve the problems existing in linear and continuous working steady-state circuits. While most software is suitable for continuous and stable working circuits, it is also suitable for switch-adjusted start-up adjustment circuits. In other words, you can simulate electrical engineering circuits, and you can read the current at any point, or the voltage between any two points, and you can do frequency response, spectrum analysis, temperature analysis, parametric analysis, Monte Carlo analysis, worst-case Situation analysis, noise analysis, etc. It can be said that the latter analysis cannot be simulated on the breadboard, but it can be run on the computer through the simulation software, so the simulation software has the advantage of being easy to use.In recent years, the development of the field of power electronics has also promoted the development of the field of energy electronics. In addition to the content of power electronics, the topic of so-called energy electronics also needs to consider material, environmental, reliability and management issues in order to solve energy conversion problems well. From this we can see that with such complex systems engineering, you can get results quickly by using computers to process information quickly. The necessity and effectiveness of simulation are obvious. This is the reason for the rapid development of circuit simulation software.Simulation software is an important tool for circuit analysis and auxiliary design in the electronic field. Using circuit simulation software to quickly analyze circuit performance parameters helps to determine the design scheme and select design parameters, thereby improving design efficiency. Overcoming the shortcomings of the traditional R&D cycle, designers can directly focus on the design level and shorten the overall design cycle. For this reason, there are various software applications for analog systems. The main applications of analog circuit simulation are EWB, SPICE PROTEL, MATLAB, etc. They have realized functions ranging from simple to complex, complex and intelligent operations, and increasingly visual interfaces.The research on analog circuit simulation software is related to the theory, implementation and application of analog circuit simulation software, and theoretical research promotes the application of software. At the same time, the application of simulation software also promotes the theoretical research of simulation software. The implementation rules of the simulation software are the bridge of "communication" between theory and application.In the process of electronic technology development, according to the depth and breadth of computer-aided technology intervention, there are three types of design schemes, that is, three stages. The first method is the so-called conventional design method, and the electronic systems involved are usually simple. The second method is often referred to as a CAD (Computer Aided Design) method and is used for data processing, simulation evaluation, design verification, etc. The third method is the so-called EDA method, which is gradually produced and completed during the development of electronic products to be more complicated and high-end, and to be intelligent, humanized, miniaturized and integrated.3. Circuit simulation software MultisimUsing Multisim software to design electronic circuits is like building a circuit on a laboratory breadboard, and it is not limited by device type, number of devices and test equipment. Multisim software can carry out simulation analysis, simulation test, design and experiment simultaneously, easy to debug and modify. The simulation experiment does not consume real test equipment and components, and the experiment cost is low. This software can complete the whole process from circuit simulation design to circuit layout generation, providing a truly convenient way for designing electronic systems and developing electronic products. It includes circuit schematic diagram input and circuit hardware description language input methods, and has rich simulation analysis functions. To handle various applications, Multisim has introduced many versions such as EWB (Electronic Workbench), Multisim 2001, Multisim 7, Multisim 8, Multisim 9, Multisim 10. Because of this advantage, vocational education in higher education institutions has a broad cognitive basis. Since Multisim 10.0 abstracts the complex content of SPICE simulation, it can be used for quick capture without knowing the detailed SPICE techniques for simulating and analyzing new designs, and is suitable for e-education. With Multisim and virtual measurement technology, you can capture and simulate everything from theory to circuit diagrams, and you can test a fully integrated design flow for prototyping and testing.By using Multisim for circuit design, you don't need to specialize in learning computer control language and various I/O commands, and you don't need to write program electronic circuit diagrams. Just place the designed virtual electronic components and virtual instruments in the Multisim10.0 circuit design window, connect the corresponding virtual components and measurement interfaces to the connections and nodes and observe the virtual measurements. In recent years, in order to complete the effective combination of theoretical teaching methods and practical teaching methods, and study the application of electronic simulation teaching methods, simulation teaching methods have brought twice the result with half the effort and provided students with a large amount of knowledge in a limited time. By using simulation software to allow students to conduct experiments and explore problems independently, students can effectively develop their learning ability and consolidate their theoretical foundation.The current latest version is Multisim 11.0. Multisim 11.0 supports Win7 and Vista systems. And powerful, flexible. Contains many versatile virtual functions that replace the various instruments commonly found in real labs, such as multimeters, function generators, oscilloscopes, and others. These virtual instruments provide a convenient and accurate way for teachers and students to obtain experimental results, and also lay a good foundation for them to use these instruments in the laboratory in the future.Experimental schematic designs are often built on solderless breadboards, and students must go through technical, documentation, and visual inspections to ensure their prototypes will function properly. Often, a lot of time is wasted correcting simple wiring errors. Therefore, the importance of computer-aided design tools is reflected. Multisim 11.0 provides a virtual 3D experimental circuit board environment, and students can learn the basics of circuit design through such a virtual program and the NIELVIS circuit experimental board that gives feedback on the correctness of the completed state.SummarizeThe theory, implementation and application of analog circuit simulation software are the basis of analog circuit simulation software research. Theoretical research promotes the development of software, and the application of simulation software also promotes the theoretical research of simulation software, while the implementation criteria of simulation software are the bridge of "communication" between application and theory.In short, circuit simulation software has a long history and a long development process. The circuit simulation software we are using now, Multisim 11.0, is a relatively complete software in the world. Both the electrical field and the energy field cannot do without circuit simulation software. Therefore, it is very important to be familiar with and master this software.The above is the historical development and current situation of circuit simulation software introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad, including MCU, voice IC, Bluetooth IC and modules, wifi modules. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS solutions, the development of Bluetooth audio, the development of children's toys, and the development of electronic education products.
07-16
2021
PCB heat dissipation design of FPGA core control boardIn recent years, with the miniaturization, integration and modularization of electronic products, the installation density of electronic components has increased and the effective heat dissipation area has decreased. Therefore, the thermal design of high-power electronic components and the board-level heat dissipation of circuit boards have attracted the attention of electronic engineers. One of the key technologies of whether the FPGA control system can work normally is the heat dissipation of the system. The purpose of PCB thermal design is to take appropriate measures and methods to reduce the temperature of components and PCB board, so that the system can work normally at an appropriate temperature. Although there are many heat dissipation measures for PCB, it is necessary to consider the requirements of heat dissipation cost and practicability. In this paper, through the analysis of the actual heat dissipation problems of the FPGA core control board, the necessary heat dissipation design for the PCB of the FPGA control board is carried out, so that the FPGA control board has good heat dissipation performance when working.1. FPGA control board and heat dissipationDesign an FPGA core control board for teaching and scientific research applications, which is mainly composed of main control chip FPGA, +3.3V and +1.2V power supply circuits, 50MHz clock circuit, reset circuit, JTAG and AS download interface circuit, SRAM memory and I/O Leading out the interface and other parts. The main control chip FPGA adopts EP3C5E144C7 in CycloneIII series QFP package of Altera Company. The structure of the FPGA core control board system is shown in Figure 1.The main sources of heat on the FPGA core control board PCB are:(1) The control board requires various power supplies such as +5V, +3.3V and +1.2V. The power module produces a lot of heat when it works for a long time. If effective cooling measures are not taken, the power module will become hot and cannot work normally.(2) The FPGA clock frequency of the control board is 50MHz, and the PCB wiring density is high. With the increase of system integration, the system power consumption is relatively high, and necessary heat dissipation measures must be taken for the FPGA chip.(3) The substrate of the PCB itself generates heat, and the copper conductor is one of the basic molding materials of the PCB. The resistance of the copper conductor-coated corrosion line itself is heated due to the loss of the alternating current power.Based on the above analysis of the heat source of the circuit system of the FPGA core control board, it is necessary to take necessary heat dissipation measures for the FPGA core control board to improve the stability and reliability of the system.2. PCB heat dissipation design of FPGA control board2.1 Power cooling designThe FPGA core control board is connected to a +5v~b DC power supply, which is required to provide a current of lA or above. The power module chooses the LDO chip LT1ll7, which converts the +5V DC power supply into the +3.3VVCCIO port voltage and +1.2VVCCINT core voltage required by the main control chip EP3C5E144C7. The LT1117 is packaged in a small SOT23 chip.Through the above analysis, it can be known that two LT1117 chips are needed to design the power circuit to meet the power supply requirements of +3.3V and +1.2V required by the FPGA. The heat dissipation of the power module is handled as follows during PCB design:(1) Because the power module will generate a certain amount of heat when working for a long time, keep a certain distance when laying out adjacent power modules. Too close a distance is not conducive to heat dissipation. When laying out, set the distance between the two LDO chips LT11l7 to 20mm or more.(2) Carry out separate copper coating treatment on the position where the LDO chip LT1117 is placed, which is conducive to heat dissipation of the power supply.(3) If necessary, add a heat sink to the LDO chip to ensure rapid heat dissipation of the power module and provide normal power supply for the FPGA chip.2.2 Heat dissipation via designPlace some heat-conducting metallized vias at the bottom of and near components that generate a lot of heat on the PCB. The heat dissipation via is a small hole that penetrates the PCB, and the diameter is about 0.4mm to 1mm. . . The aperture should not be too large, and the distance between the vias should be set at 1 mm to 1.2 mm. The via holes penetrate the printed circuit board, so that the heat on the front of the printed board is quickly transmitted to other heat dissipation layers along the back of the PCB, and the components on the heating surface are cooled quickly, and can effectively increase the heat dissipation area and reduce thermal resistance, increasing the power of the circuit board density.2.3 FPGA chip heat dissipation designThe main source of FPGA chip heat is dynamic power consumption, such as core voltage power consumption and I/O voltage power consumption, power consumption generated by memory, internal logic, and the system, and FPGA control of its functional modules (such as video, audio modules, etc.) will generate power Therefore, it is necessary to dissipate heat on the FPGA chip as heat is generated. When designing the QFP package of the FPGA chip, a copper foil with a size of 4.5mmX4.5mm is added to the center of the FPGA chip, and a certain number of heat dissipation pads are designed, and heat sinks can also be added according to actual needs.2.4 Copper clad heat dissipation designPCB copper coating can not only improve the anti-interference ability of the circuit, but also effectively promote the heat dissipation of the PCB board. There are generally two methods of copper cladding in PCB design using AltiumDesignerSummer09 software, that is, large-area copper cladding and grid-shaped copper cladding. The disadvantage of large-area strip copper foil is that the PCB board will generate a lot of heat when it works for a long time, which makes the strip copper foil easy to expand and fall off. Therefore, considering the good heat dissipation performance of PCB, a grid-shaped copper foil is used in the design of PCB copper cladding, and the grid is connected to the grounding network of the circuit to improve the shielding effect and heat dissipation performance of the system.SummarizePCB heat dissipation design is a key link to ensure the stability and reliability of PCB boards, and the choice of heat dissipation method is the primary factor to be considered. The design and application of specific heat dissipation measures is the core issue of PCB heat dissipation. In this paper, when designing the PCB of the FPGA core control board, the analysis of the heat source of the FPGA control system is the starting point, and according to the actual heat dissipation requirements, the power module of the FPGA control board, the FPGA control chip, the heat dissipation vias and the copper heat dissipation are designed. The heat dissipation method adopted by the FPGA control board has the characteristics of practicability, low cost and easy realization.The above is the PCB heat dissipation design technology of the FPGA core control board introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, Bluetooth IC and module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
07-15
2021
PCB Design Specifications for ManufacturabilityDFM has the advantages of shortening the development cycle, reducing costs, and improving product quality. It is the way for enterprise products to succeed.PCB (Printed Circuit Board, printed circuit board) is an important electronic component in electronic products. It is the carrier for electronic components to realize electrical connection, and PCBA (Printed Circuit Board Assembly, PCB assembly, that is, to assemble electronic components on the PCB board The formed semi-finished product) is the hardware body that realizes the function of the electronic product circuit system. This article aims at the manufacture of PCB components in electronic products, and briefly discusses some specifications of PCB design from various aspects to achieve the purpose of realizing the manufacturability of PCB components.1. Basic principles of PCB DFM design(1) Reduce the manufacturing process and cost of PCB assembly, and try to place the parts on the main welding surface of the PCB. (2) The same or similar components should be placed in the same column or row and the polarity should point in the same direction. (3) Distribute the components evenly according to the size and quantity on the PCB to avoid deformation of the PCBA during the reflow process and wave soldering process. (4) Connectors and sockets should be placed on the main soldering surface of the PCBA (5) Do not design through-hole devices on both sides of the PCB. (6) Automatic assembly should be considered as far as possible in the design, and manual operation should be minimized. (7) Avoid using jumpers and any additional manual operations. (8) Consider the requirements of equipment debugging in the design. (9) Errors of various variables are considered in the design.2. PCB shape and size designThe shape and size of the PCB are determined by the PCB transmission method and the mounting range of the placement machine. According to the equipment capability index, the PCB assembly size range that the usual PCB component manufacturers can produce is: minimum 50 (length) * 50 (style) mm, maximum 520 (length) * 400 (width) mm, PCB thickness 0.2mm ~~4.5mm.In order to improve the utilization rate and balance rate of SMT machines, it is usually required that the size of the PCB panel be as large as possible (the more single panels in the same panel, the better, as long as it does not exceed the allowable size range of the equipment), of course, the panel must also be considered The ease of handling and the hidden danger of compression deformation of the panel.3. PCB process sideMost assembled PCBs have upper and lower track sides, also known as PCB process sides. The width of the transmission side of the PCBA assembly equipment is usually designed to be 5-10mm, which is used to drive the PCB assembly while contacting the PCB process.Usually, components cannot be placed within 3mm from the actual PCB board to the edge of the PCB, so as to prevent the machine track from clamping the component pads during circuit board assembly and making it impossible to install. If there are components within 3mm of the edge of the single board, the board must be added with a PCB process edge.If the body of the assembly component exceeds the edge of the board or is flush with the edge of the board, the bare board is not allowed to be placed on the conveying equipment for production, and the edge of the board is not allowed to be set in the V-Cut paneling method, but the edge of the board needs to be hollowed out according to the specific situation Partially or by means of stamp holes to connect the edge of the board. If the board must be produced using SMT production equipment, it is necessary to use a special jig carrier board operation.If the body of the plug-in component exceeds the edge of the board or is flush with the edge of the board, the wave soldering process must be performed after board separation. The gold finger edge on the PCB cannot be used as a transmission edge.4. Connection design of V-CUT and stamp hole of PCB panelWhen the PCB board and the board are connected in a straight line, the edge is flat and does not affect the device installation, the PCB panel can be connected to each small board by V.cUT. V-CUT is a straight-through type and cannot turn in the middle.The recommended board thickness of the PCB designed using V-CUT panel is 0.6O2.0mm. The depth of the groove is (for the commonly used FR4PCB material) the thickness of the upper and lower 1/3 boards. For the V-CUT connected PCB that needs to be automatically divided by the machine, in order to ensure that there will be no exposed copper defects during the PCB division process, it is required that all traces and copper foils be more than 0.50mm away from the edge of the board during PCB layout design, while the actual components The distance between the physical edge and v_CuT should be greater than lmm.If the connection between the boards in the PCB panel is not a straight line, you can use the stamp hole connection to connect each small board in the panel. Generally, the connection part of the stamp hole adopts four through holes, the stamp hole cannot be directly below the part, and the minimum distance from the stamp hole to the wiring edge is 0.5ram.5.PCB optical positioning point designIn order to facilitate accurate optical positioning of SMT production equipment, FiducialMark (optical positioning point) is a necessary design for PCB. The PCB optical positioning point is very important for SMT machine parts, and its quality will directly affect the accuracy of machine placement.Global optical positioning point (Globalfiducial mark): Generally, the PCB is required to have at least 2 global optical positioning points (usually also called large board Mark points), and its size and shape should be consistent, while 3 to 4 global optical positioning points are necessary for SMT production. better.At least 2 global optical positioning points should be distributed on the diagonal of the panel. If the PCB needs to be produced on both sides, there must be global optical positioning points on both sides. track edge) plus anchor points.The optical positioning point is usually designed as a solid circle with a diameter of 1.0mm. In the circular area where the center diameter of the optical point is the diameter of the solid circle plus 2.0mm, solder mask opening is required. The optical point manufacturing process requires the surface to be clean and flat, the edges smooth and neat, and the color to be clearly different from the surrounding background color (the key is to have a clear contrast with the color of the reference point). There are no pads, vias, test points or silk screen marks in the background of the optical dots. The optical point cannot be cut by V-Cut and cannot be recognized by the machine.6. Design of PCB pads and connected leads(1) When the size of the pad is asymmetrical, or the ends of the two components are designed on the same pad, suspension bridges and displacements will occur due to asymmetrical surface tension. Need to avoid.(2) When the pad is connected to a large area of ground, the cross paving method and 45 should be preferred. Paving method. The length of the wire drawn from the large-area ground or power line should be greater than 0.5mm, and the width should be less than 0.4mm.(3) Try to make the wiring connected to the pads symmetrically distributed. Reduces unbalanced solder flow due to asymmetric distribution, causing component rotation or misalignment.7.PCBA test point designFor PCBs of common jfl consumer electronics products, there is usually at least one test point on each line network, at least 4 test points on each power line network, and at least 6 test points on the ground network. All test points are distributed on the bottom of the PCB as much as possible, which facilitates the manufacture of test fixtures, reduces the cost of manufacturing test fixtures and increases the stability of the fixtures.The center distance between two adjacent test points should be at least greater than 1.25mm, the center of the test point should be greater than 2.54mm from the edge of the board (excluding the broken edge), and greater than 1.25mm from the edge of the screw hole. The test point and the periphery of the part (zero even The distance between the test point and the periphery of the part (with a height of 3mm or less) should be less than 1.27mm, the distance between the test point and the periphery of the part (with a height of 3-6mm) should be less than 3.3mm, and the distance between the test point and the periphery of the part (with a height of 6mm or more) should be more than 3.81mm.8.PCB stack designThere are generally two designs for PCB stacking: one is the structure of copper foil plus core board (Core), referred to as the Foil stacking method; the other is the core board. (Core) stacking method, referred to as Core stacking method. The PCB stacking method is recommended to use the Foil stacking method, and the Core stacking method can be used when multi-layer boards of special materials and boards are mixed.The outer layer of the PCB generally uses 0.5oz to Ioz (1oz=0.35 micron) copper foil electroplating, and the inner layer generally uses 1OZ copper foil: try to avoid using a core board with inconsistent copper foil thickness on both sides of the inner layer.The PCB stackup adopts a symmetrical design. Symmetrical design refers to the insulation layer thickness, prepreg type, copper foil thickness, and graphic distribution type (large copper foil layer, circuit layer) as symmetrical as possible relative to the vertical center line of the PCB.9.PCB surface treatment9.1 Hot air leveling processThis process is to cover the tin-silver-copper alloy on the final exposed metal surface of the PCB. The thickness of the tin-silver-copper alloy coating required for hot air leveling is 1 micron to 25 microns. The hot air leveling process is difficult to control the thickness of the coating and the pattern of the pad. It is not recommended to be used on PCBs with fine-pitch components, because the fine-pitch components have high requirements on the flatness of the pads.The thermal shock of the hot air leveling process may cause PCB warpage, and this surface treatment method is not recommended for ultra-thin PCBs with a thickness of less than 0.7mm.9.2 Electroless nickel gold processElectroless nickel gold is the abbreviation of nickel immersion gold. The electroless nickel layer coating used on the copper metal surface of PCB is 2.5 microns to 5.0 microns, and the thickness of immersion gold (99.9% pure gold) layer is 0.08 micron 0.I27 micron . It can provide a relatively flat surface, and this process is suitable for PCBs with fine-pitch components. 10.3 Organic Solderability Protective Film Process This process is abbreviated as OSP, which refers to the surface coverage of the exposed PCB copper surface with specific organic substances. At present, the only recommended protective layer for the Ke machine is Enthone'SEntekPlusCu-l06A, and its thickness requirement is 0.2 microns to 0.5 microns, because it can provide a very flat PCB surface, especially suitable for PCBs with fine-pitch components.SummarizeIn the era of electronic information, the updating speed of electronic products is very fast, which means that the market competition of electronic products is very fierce. In order to adapt to market competition and complete the assembly and manufacture of electronic products more effectively, the content of manufacturable PCB design work has become more and more abundant. It can also bring direct cost savings to manufacturers while improving production capacity and controlling quality. . Only by grasping the unity of design and production can they promote each other and achieve the goal of enhancing market competitiveness.The above are the details of the PCB design specifications for manufacturability introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, Bluetooth IC and module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
07-14
2021
Development and Application of EDA Technology in PCB DesignWith the marketization of scientific research and technology development, it has become increasingly difficult to complete the design of complex electronic systems in a relatively short period of time using traditional electronic design methods. In order to adapt to this situation, the increasingly perfect EDA technology is gradually replacing the traditional electronic design methods. EDA is currently the latest and most comprehensive electronic design technology and tool. Its appearance provides a new design method for electronic design workers. It covers the main links of electronic design and simulates the designed circuit. And signal integrity analysis, so as to comprehensively verify the circuit design and printed board design, obtain the best design parameters, and conduct product characterization.1. Introduction to EDA software"EDA" is Electronic Design Automation (Electronic Design Automation), which is a software tool that can help people design electronic circuits or systems. This tool can make it possible to design more complex circuits and systems. At present, the EDA software that has entered our country and has extensive influence includes: muhisim7, OW_AD, Protel, Viewlogio, Mentor, Synopsys, PCBWId, Cadence, MicmSim, etc. These softwares have their own characteristics and are roughly divided into chip-level design tools and circuit board-level design. tools, programmable logic device development tools, and circuit simulation tools; Among them, Protel is the most popular and widely used software of choice for printed circuit board (PCB) design in China. It is produced by the Australian protdTechnology company. In the past, it was only used To carry out schematic diagram input and PCB layout design, starting from Protel 98, adding analog-digital hybrid circuit simulation module (SIM) and programmable logic device design module (PLD), in 1999 Protel launched a more powerful EDA comprehensive design environment Protel 99, it integrates all the content of EDA into a complete EDA software, so the software has great potential for development, but its most distinctive and powerful functions are still schematic diagram input and PCB layout design; in addition There are also PCB design software supporting Ultiboard and Multisim, PCB production software packages supporting PCBWizard and LivaWire, and so on.2. The development history of EDA technologyEDA technology is a comprehensive technology involving computer graphics, microelectronics technology and other disciplines. With the development of computer, integrated circuit and electronic system design, it has experienced a process from shallow to deep.Since the mid-1960s, people have used various computer-aided design tools to replace manual operations for IC layout editing and PCB layout and routing, which has changed the traditional manual method of drawing and designing integrated circuits. Due to PCB layout and routing tools Restricted by the computer working platform, the design work supported by it is limited, and the performance is relatively poor.In the 1980s, since various design tools (such as schematic diagram input and layout automatic layout) were complete, people used unified data management technology to integrate various tools into a system and provide a standard component library to make design work convenient and fast. However, in the design process, the degree of automation and intelligence is not high, and the interfaces of various EDA software are vastly different, making it difficult to learn and use, and they are incompatible with each other, which directly affects the connection between design links.Since the 1990s, the level of electronic technology has reached the sub-micron level, and people have begun to pursue the automation of the entire design process, focusing on creative solutions and conceptual ideas, so as to improve design efficiency and shorten product development cycles. . At this time, EDA tools not only have the ability to design electronic systems, but also provide system-level design capabilities independent of processes and manufacturers, and have high-level abstract design concepts.3.The basic characteristics of EDA technologyUsing EDA tools, electronic designers can start designing electronic systems from concepts, algorithms, protocols, etc., and a lot of work can be done by computers, and the entire process of electronic products from circuit design, performance analysis to IC layout or PCB layout design can be done on the computer Completed automatically.(1) Use the method of software design to design the hardware. The conversion of the hardware system is automatically completed by the relevant development software. The design input can be the schematic diagram V H DL language. Through the test of the software design method, the realization of the hardware circuit with specific functions Design, and the modification of hardware design is as fast and convenient as modifying software programs. The whole process of design hardly involves any hardware, and the operability and product interchangeability are strong.(2) The software tools of different companies are integrated into a unified computer platform, making it a complete EDA system, realizing the optimal combination and resource sharing among various EDA tools; using a unified database, different design styles and application occasions The requirements of different EDA tools are integrated on the same workstation, thereby standardizing the EDA framework; each simulator performs co-simulation on the same design, which further improves the work efficiency and flexibility of the EDA system.(3) The EDA design method, also known as the chip-based design method, has a higher degree of integration and can realize on-chip system integration, more complex circuit chip design and application-specific integrated circuit design, so that the product is small in size, low in power consumption, and High reliability; in-system programming or on-site programming is possible, making device programming, reconfiguration, and modification simple and convenient, and online upgrades can be realized; various simulations can be performed, the development cycle is short, the design cost is low, and the design flexibility is high.(4) EDA technology automatically completes the whole process of electronic products from circuit function simulation, performance analysis, optimization design to result test on the computer according to the design input file, and automatically generates the target system, so that designers do not have to learn many in-depth professional Knowledge can also avoid many derivations and calculations to obtain optimized design results. The degree of design automation is high, which reduces the workload of designers and improves development efficiency.4. EDA technical design processEDA technology has excellent functions in various aspects such as product design, product testing and product development. It can help professional and technical personnel to carry out rapid product design and testing, and truly achieve "design is correct".(1) In terms of design methods, EDA technology has brought fundamental changes to the field of electronic design. It is a future-oriented electronic design concept. Using EDA software, the traditional "circuit design + hardware test + debugging welding" The mode has changed to automatic completion on the computer. People design the schematic model of the electronic circuit in the computer, then verify its theoretical feasibility, and then draw its printed circuit board, so as to complete the transformation from the logical connection of the schematic diagram to the The transformation process of the physical connection of circuit components. Change the traditional cumbersome and lengthy process of sub-product design cycle, which is long, consumes a lot of materials, high design cost, and is not conducive to product replacement, and solves the problem of relying on human factors and facing large-scale electronic circuits when there are problems in the product. question.(2) In terms of design method, the designer adopts a new high-level "top-down" design method. Firstly, the functional block diagram is divided and structurally designed at the top layer, and then the simulation and error correction are performed at the block diagram level. Use a hardware description language to describe the high-level system behavior, verify it at the system level, and then use synthesis tools to optimize the product. The corresponding physical implementation level can be a printed circuit board or an application-specific integrated circuit; integrated with past selection standards Compared with constructing a new system from the "bottom-up" circuit, the main simulation and debugging process of the design is completed at a high level, which is not only conducive to early detection of structural design errors and avoiding waste of design work, It also reduces the workload of logic function simulation and improves the first-time success rate of design.(3) In the circuit design process, poor signal integrity is not caused by a certain factor, but by multiple factors in the board-level design. The designer first determines the design plan, selects the appropriate components, and then Design the circuit schematic diagram according to the specific components, and then carry out the first simulation such as fault analysis, AC and DC analysis of the analog circuit, and transient analysis. This time the simulation is mainly to input the design into the EDA tool for simulation, check the correctness of the design plan in terms of function, check the correctness of the logic function; ensure the quality of the signal on the signal line, pay special attention to the high-speed circuit, the used The solution to signal integrity problems caused by excessive chip switching speed, unreasonable layout of connecting components, and unreasonable interconnection of circuits mainly includes crosstalk, reflection, overshoot and undershoot, oscillation, signal delay, etc.(4) Through the EDA system, most of the design defects can be eliminated in advance, and the data and response waveforms similar to the actual circuit can be simulated on the computer. Designers do not need to describe the circuit through the gate-level schematic diagram, but to describe the function according to the design goal, and get rid of the shackles of the circuit details. Before making the PCB board, they can also perform thermal analysis, noise and interference analysis, electromagnetic compatibility analysis, and reliability analysis. etc., and the parameters of the analyzed results can be reverse marked back to the circuit diagram, and the second simulation can be performed to test the feasibility of the PCB board in the actual working environment; in the process of board making, the computer builds electromagnetic interference and thermal interference into mathematical Models are excluded to maintain routing quality. It can be seen that EDA technology enables designers to fully understand the functional characteristics and physical characteristics of the system before the actual electronic system is produced, thereby eliminating development risks in the design stage, shortening development time, and reducing development costs.SummarizeThe development and application of EDA technology has become the core of modern electronic design. With the acceleration of electronic product updates, EDA technology is the source of electronic product development. Its application level and popularity have become a measure of the modernization level of a country's electronic technology. Therefore, the development of EDA technology will be a major technological revolution in the field of electronic design and the electronics industry. Mastering EDA technology has become an important task for designers of electronic circuits and hardware systems today.The above are the details of the development and application of EDA technology in PCB design introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, Bluetooth IC and module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
07-13
2021
Rapid Manufacturing System of PCB Board Based on Laser Direct Writing Circuit TechnologyThe research and development of new electronic products needs to go through the process of product design, production processing and debugging, among which, the design and manufacture of PCB board is one of the most critical links. Most components can be purchased in the market as finished products, and PCB boards must be designed and manufactured according to different products; therefore, the cycle length of PCB board design and manufacturing has a great impact on the development cycle of new products.At present, according to the production process of the PCB board factory, even if only one sample PCB board is produced, it is the same as the process flow of producing a large number of PCB boards, which requires data preparation, light drawing, blanking, drilling, metallized holes, etc. Film or screen printing, exposure, graphic plating, etching, solder resist coating, tin spraying, silk screen characters, appearance processing and cleaning, etc. Dozens of processes. In this production mode, it usually takes at least a few days to a week from the confirmation of the PCB design documents by the designer and the PCB manufacturer to the final completion of the PCB manufacturing. This process can meet the production cycle needs of batch products, but it is not suitable for the production of sample PCB boards. In the stage of the first prototype, in view of the fact that there will always be some uncertain risks in technology, the design and commissioning time of the product is uncontrollable, and problems often arise in design, commissioning, design modification, and commissioning. In this case, Prototype PCB manufacturing cycles of several days are unacceptable.In order to solve the problem of a long production cycle of a single sample PCB board, a rapid manufacturing system for PCB boards has been developed in recent years, which can complete the manufacture of sample PCB boards within 1 working day at the fastest. This paper introduces and compares the three common PCB board rapid manufacturing systems at present, and gives the process technology of the PCB board rapid manufacturing system based on laser direct writing circuit technology.1. PCB board rapid manufacturing systemThe common process steps of the PCB rapid manufacturing system are as follows: 1) Drilling and metallization holes; 2) Making circuit graphics; 3) Making solder resist graphics; 4) Making character graphics; 5) Soldering anti-oxidation treatment. Among them, the key steps that affect the quality of the finished PCB board are the production of metallized holes and circuit graphics.PCB board rapid manufacturing system can be divided into three categories according to the working principle of circuit graphics production: chemical etching, physical engraving and laser direct writing processing.1) Chemical etching. The chemical etching method is to use a chemical etching solution to remove the insulating material that needs to be removed from the substrate to produce a suitable circuit pattern. The chemical etching method has a certain impact on environmental protection due to the use of a series of acid and alkali reagents, and there are many chemical etching processes, the process is relatively complicated, and it is more difficult to implement than the other two methods, so it is not the main promotion now. Way.2) Physical engraving. The principle of the physical engraving method is to convert the line information of the circuit board into three-dimensional position information, and then control the engraving tool to move along the XYZ axis guide rail through the stepping motor, so as to control the engraving tool to carve on the blank circuit board. According to this method, the production time of a typical double-sided circuit board is about 1 to 2 hours, and a sample PCB board can be made within 1 day; The processing cannot be well guaranteed. For example, when the hole diameter is less than 150 μm, the processing cost will be greatly increased due to the fragility of the mechanical drill bit, and the processing progress will also be affected.3) Laser direct writing. The principle of laser direct writing is to select lasers of different wavelengths according to the different materials of the object to be processed, and use high-power laser beams to irradiate the surface of the material to cause a photochemical reaction on the surface of the material, and finally process the desired circuit pattern. Compared with the physical engraving method, because of the high energy density of the laser beam and the fast processing speed during the processing, it basically has no effect on the non-laser irradiated parts, and there is no mechanical contact with the processed parts, so laser processing will not affect the processed material. Mechanical stress, at the same time, the metal layer can be removed cleanly and without residue, and the circuit pattern can be processed.2. Laser direct writing circuit technologyLaser direct writing circuit technology is a technology that uses the principle of laser direct writing to process the required circuit patterns on the copper-clad layer or gold-plated layer of the PCB.At present, the most advanced laser processing equipment on the market mainly uses lasers with two spectrums of green light or purple light for processing, and it is already possible to completely use laser direct writing technology to complete the production of circuit graphics. The metal layer can be removed quickly with a single laser beam without any mask during processing. Especially based on the 355nm ultraviolet laser, most of the materials that make up the PCB board substrate can be processed, including copper, polymer resin materials and glass fibers.The thermal shock to the material is smaller by using the ultraviolet laser.The ultraviolet laser has high photon energy. When the ultraviolet laser is irradiated on the surface of the processed material, the molecules on the surface of the material absorb the photons in the ultraviolet laser, interact with their own electrons, and directly destroy the chemical bonds connecting the atomic components of the material, breaking the molecular chain. The broken small molecules are ejected strongly outwards in the form of an explosion, breaking away from the surface of the material.The use of laser processing has great advantages in the stability of processing accuracy and the operation and maintenance of later equipment. The theoretical use time of the laser generator, the core component of the laser processing equipment, is usually 100,000 hours, and the actual service life is generally more than 5 years; the laser beam emitted by the laser generator can maintain a relatively stable state for a long period of time In this way, the inconsistency of processing accuracy caused by the wear and tear of milling cutters and drills in traditional physical engraving methods can be avoided; in terms of daily maintenance of equipment, laser processing equipment only needs to be dust-proof and clean, and does not need to be lubricated And other operations can greatly reduce the maintenance costs of later equipment operation.3. PCB board process technology3.1 DrillingIn terms of drilling, there are three methods of using ultraviolet laser to process holes: laser punching, laser trepanning and laser spiral processing.1) Laser punching. The process method is to keep the position of the laser beam unchanged, set a high repetition rate laser pulse, and continuously process the position of the hole. The pulse frequency of laser processing equipment can generally be set to 250-300kHz, and the depth of the hole will increase at each pulse width. In this process, the size of the hole depends on the focused spot size. The focus spot diameter of ultraviolet laser processing equipment can be as small as 15μm, so this process can complete the processing of smaller diameter holes, especially suitable for the processing of blind holes.2) Laser perforation. The process method is to set the laser beam at the position of the hole, and make a circular motion around the outer circumference of the hole. After the first round, a circular groove will be machined at the position of the outer circumference of the hole. Every time you walk around, the depth of the groove will increase a little. When processing from the top of the PCB to the bottom, after the bottom is pierced, the material of the cylinder connected to the bottom will fall off during processing, forming a through hole. This process method is suitable for processing through holes, but not suitable for processing blind holes, because if the hole is not pierced, the cylindrical material in the center area of the hole will remain in the middle of the hole during processing.3) Laser spiral processing. The process method is to set the laser beam to start processing from the center of the hole and move outward from the center in a spiral manner. As the laser beam moves, the depth and diameter of the hole grows. This process method is suitable for processing large-sized holes.In actual processing, the above three process methods can be selected according to the type and size of the hole, and the copper on the surface layer can be directly removed by adjusting the laser pulse frequency and energy, and then the lower layer material can be removed. Compared with other lasers, the bottom of blind holes processed by ultraviolet laser is cleaner and free from carbonization, which provides a good surface treatment for post-process metallized holes.In view of the characteristics of laser processing, it has considerable advantages in processing micro-holes and blind holes. However, in actual production, for PCB boards with a thickness of more than 0.5mm, when processing through holes with a diameter of more than 0.8mm, the efficiency of drilling with laser equipment is not as high as that of drilling with physical engraving machines; For PCB boards with a thickness > 0.5mm, it is preferable to use a physical engraving machine for drilling.3.2 Metallized holesAfter the hole is formed, metallized hole treatment is required to achieve the effect that the hole is metallized and penetrated. Metallized holes should have good mechanical toughness and electrical conductivity. There are two methods of metallized holes: physical metallized holes and chemical metallized holes.1) Physical metallization holes. The principle is to use conductive paste to make the holes conduct electricity. The minimum diameter of the through hole that the system can process is 0.4mm, and the maximum diameter-to-depth ratio of the hole is 1:4. The contact resistance after the metallized hole is about 20mΩ. The technological process of physical metallization holes is as follows: a. Paste the special protective film on both sides of the PCB board; b. Use laser processing equipment to drill holes (for through holes with PCB board thickness > 0.5mm and hole diameter > 0.8mm, physical engraving machine drilling can be given priority); c. Place the PCB board on the vacuum adsorption table, and use a rubber scraper to apply the conductive paste on the protective film on one side of the PCB board by brushing; d. Turn on the vacuum adsorption function, and suck the conductive paste into the hole under the action of vacuum; e. Flip the PCB board, repeat steps c and d; f. Remove the protective film, and cure the conductive paste in an oven with a curing temperature of 160°C and a curing time of 30 minutes. The advantage of physical metallized holes is that it is easy to operate, does not need to use electroplating process, and does not use chemicals in the process, which is more environmentally friendly; but the penetration reliability of metallized holes is not as good as that of chemical plating process.2) Chemically metallized holes. The principle is the principle of electroless plating. The process is divided into four basic steps: pre-dipping→activation→microetching→electroless copper plating. The details are as follows: a. The pre-soaking process can choose a solution whose main chemical composition is 5% Na2CO3. Under heating conditions, it can remove sweat stains, oil stains, etc. produced by the PCB board in the previous process; b. The black hole liquid can be used in the activation process, and its main chemical liquid composition is C (graphite) particle solution. The main function of this solution is to complete the uniform layer of conductive carbon film on the inner wall of the hole; c. 5% Na2S2O8 solution can be used in the micro-etching process, which mainly completes the dissolution of carbon black on the surface of the base material after black holes; d. The electroless copper plating process can choose a CuSO4 solution whose main chemical composition is 10%. The main function of this solution is to serve as a conductive substance for electroplating to realize metallized holes. At present, the more advanced desktop chemical metallization hole equipment has optimized the anode plate and added a reverse pulse electroplating power supply. The combination of these two technologies can effectively ensure the uniformity of electroplated copper thickness.3.3 Line graphics productionIn terms of circuit pattern forming and processing, the use of ultraviolet laser equipment can realize direct writing of circuit patterns on the metal coating layer of PCB boards. In actual production, setting a laser beam with short pulse time and high pulse energy has less thermal shock effect on the circuit, and has a better effect on processing fine-pitch circuits and radio frequency microwave circuits.3.4 Production of solder mask graphics and character graphicsThe solder mask layer is a protective film with a specific pattern formed on the surface of the PCB board during PCB board production. The production principle of solder resist graphics and character graphics is to use screen printing ink to the surface of the PCB board, and then use heating to cure it. The specific process steps are as follows: printing photosensitive solder resist ink→solder resist graphic exposure→solder resist graphic development→printing photosensitive character ink→character graphic exposure→character graphic development→solder resist and character ink thermal curing.When printing ink, the PCB board rapid manufacturing system does not use the method of making a screen mold, but uses a laser printer to directly print the photosensitive material into the film sheet required for printing ink. This does not require the waiting time (usually 1d) for making the screen mold, thus greatly shortening the production cycle, and the whole process can be completed within 1 to 2 hours.3.5 Flux anti-oxidation treatmentThe principle of soldering anti-oxidation treatment is to use chemical reagents to react with the copper surface, and an organic film layer of a certain thickness can be formed on the bare copper. The organic film layer can effectively isolate the pad of the copper layer from the air, prevent the pad from being oxidized, and ensure soldering performance. The process can be completed within 1 to 2 hours through four simple operations, that is, degreasing → micro-etching → pickling → film formation, as follows.1) The degreasing process can choose a solution whose main chemical composition is 5% Na2CO3. Under heating conditions, it can remove sweat stains and oil stains on the PCB board in the previous process.2) A 5% Na2S2O8 solution can be used in the micro-etching process, and a rough copper surface can be formed after micro-etching, which is convenient for film formation. The thickness of the microetch directly affects the film formation rate, so to form a stable film thickness, it is very important to maintain the stability of the microetch thickness. Generally, it is more appropriate to control the microetch thickness at 1.0-1.5 μm.3) The pickling process can use 1% dilute H2SO4 solution, the main purpose is to remove the oxides that may be produced by the PCB board due to contact with air in the previous process.4) OSP organic reagent can be used in the film forming process. The solution can form a layer of hydrophobic organic protective film with a thickness of 0.3-0.4 μm on the copper surface through chemical reaction. This film is used to protect the copper surface in the normal environment. It will no longer continue to oxidize, and at high welding temperatures, the protective film is easily removed by flux, and can form a firm solder joint with molten tin in a very short time.The solderability of PCB boards treated in the above way can be preserved for up to 3 months if they are stored in vacuum packaging. After the extended period, the solderability of the pad will decrease.epilogueThe PCB board rapid manufacturing system based on laser direct writing circuit technology solves the problem of insufficient precision of physical engraving; and because it adopts non-contact processing, there is no mechanical stress on the PCB board, which can further improve the reliability of the circuit. It is a good choice for making sample PCB boards. It should be pointed out that the PCB board processed by this system can not guarantee the quality reliability in a long period of time because it has only undergone simple soldering anti-oxidation treatment, so it is only suitable for the verification of the design scheme, and cannot be used. For formal industrial product delivery.The above is the PCB board rapid manufacturing system based on laser direct writing circuit technology introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, Bluetooth IC and module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
07-12
2021
Regardless of whether it is a discrete component amplifier circuit or an integrated amplifier circuit, the final stage must be connected to the load, and to drive the load, the final stage of the amplifier circuit must output relatively large power. The amplifying circuit that can provide enough power to the load is called a power amplifying circuit, or power amplifier for short. In terms of energy control and conversion, there is no essential difference between the power amplifier circuit and other amplifier circuits, but the power amplifier does not simply pursue high output voltage or high output current, but pursues the output as much as possible under a certain power supply voltage. Possibly large power and efficiency. Different operating states of the amplifier have different characteristics, so in practice, different operating states should be selected according to different requirements of the power amplifier circuit.1. Characteristics and application of power amplifierPower amplifying circuits can be divided into Class A, Class B, Class A and B, and Class C according to the different conduction times of transistors.1. Class A power amplifierWhen the static operating point of the power amplifier tube is set in the middle of the load line, the power amplifier tube is in the conduction state during the entire period of the input signal, which is called a Class A working state, referred to as a Class A power amplifier. The advantage of Class A power amplifier is that the nonlinear distortion is small, but the disadvantage is that the static current is large, the tube consumption is large, the output power is small, and the efficiency is low. The theoretical maximum value of efficiency is 50%. Due to the small nonlinear distortion, Class A power amplifiers can be used in broadband power amplifiers. Due to low efficiency and low output power, Class A power amplifiers can be used in low-power amplifier circuits, and power synthesis technology can also be used to realize the joint work of multiple power amplifiers to obtain greater output power.2. Class B power amplifierWhen the static operating point of the power amplifier tube is set in the cut-off area, the power amplifier tube is only turned on when the signal is positive, and it is turned off when the signal is negative, that is, the power amplifier tube is only turned on within half a cycle of the input signal, which is called Class B Working state, referred to as Class B power amplifier. The advantages of Class B power amplifiers are small tube consumption and high efficiency. The theoretical maximum value of efficiency is 78.5%, and the efficiency in practical applications is about 50%. The disadvantage is that the output signal lacks half a cycle and the distortion is large. In order to compensate for this distortion and output a complete signal waveform, two complementary triodes are usually turned on in turn to form a complementary symmetrical power amplifier circuit. However, when the two triodes are turned on in turn, due to the existence of the dead zone voltage, when the input signal is lower than the dead zone voltage of the power amplifier tube, the tube is still in the cut-off state, so there is distortion at the intersection of the output waveforms of the two tubes. This is called "crossover" distortion.3. Class A and B amplifiersWhen the static operating point of the power amplifier tube is set at the lower part of the load line and close to the cut-off area, in the entire cycle of the input signal, the conduction time of the power amplifier tube is greater than half a cycle and less than one cycle, which is called Class A and B working conditions, referred to as A and B class power amplifier. In the Class B complementary power amplifier circuit, add proper bias to the bases of the two triodes, so that the two triodes are in the micro-conduction state when they are static, and when the two triodes are turned on in turn, the alternating process is relatively Smoothing, which reduces crossover distortion. The typical application of Class A and B power amplifiers is audio amplification output.4. Class C power amplifierIn the entire cycle of the input signal, the conduction time of the power amplifier tube is less than half a cycle, which is called a Class C working state, referred to as a Class C power amplifier. In addition to the power amplifier tube, the Class C power amplifier also includes an output tuning circuit that functions as both a filter and an impedance matching function. At the same time, the base bias circuit and the collector bias circuit have special requirements. Class C power amplifiers are divided into three working states: undervoltage, critical and overvoltage due to different working conditions. When the triode works in the amplification region and the cut-off region, it is called an undervoltage state. When the triode just does not enter the saturation region, it is called a critical working state. When the triode enters the saturation region, it is called an overvoltage state. The waveforms of the collector output in the three states are sharp cosine pulse, slightly flat cosine pulse and top concave cosine pulse respectively. The Class-C amplifier and the resonant circuit together constitute a Class-C resonant power amplifier or a Class-C frequency multiplier. Class C power amplifiers work in overvoltage and critical states with high efficiency, which can reach 100% in theory, and the actual efficiency is about 70%.2. Typical power amplifier circuit and its applicationAccording to different output coupling methods, the power amplifier circuit is divided into transformer coupling power amplifier circuit, no output transformer (OTL) power amplifier circuit, no output coupling capacitor (OCL) power amplifier circuit and bidirectional push-pull no output transformer (BTL) power amplifier circuit. amplifier circuit, etc. In addition, power amplifying circuits can also be divided into discrete component power amplifying circuits and integrated power amplifying circuits.With the development of electronic technology, integrated circuits have become the core devices in modern electronic circuits and are widely used in various electronic devices. LM386 is an audio integrated power amplifier circuit, which has the advantages of wide frequency response, low power consumption, adjustable voltage gain, wide applicable power supply voltage range, few external components and small total harmonic distortion. It is widely used in tape recorders, radios and on the intercom.With the further study of the amplifier circuit, its classification is more and more, and its application is more and more extensive. Only by mastering the various states of the amplifying circuit can it be flexibly applied as needed.The above are the characteristics and applications of the power amplifier circuit introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad, including MCU, voice IC, Bluetooth IC and modules, wifi modules. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS solutions, the development of Bluetooth audio, the development of children's toys, and the development of electronic education products.
07-11
2021
With the continuous development of the electronic industry, electronic products emerge in endlessly. In the production process of electronic products, the design of electronic circuits is very important, which greatly affects the performance of products. Therefore, when designing electronic circuits, it is necessary to follow certain design principles and adopt appropriate design methods. Only in this way can we ensure the scientificity of circuit design and the performance and quality of electronic products.1. Principles of electronic circuit design1. The principle of integrity: When designing an electronic circuit, it is necessary to start from the whole and focus on analyzing the relationship between the components in the electronic circuit, as well as the relationship between the electronic circuit as a whole and the external environment. It is necessary to fully grasp the overall nature of electronic circuits, determine the types of electronic circuits, clarify the functions to be realized and the measures to be taken to realize these functions, and then determine the overall design of electronic circuits. The principle of integrity needs to be established on the basis of comprehensive control and guidance: first, electronic circuit analysis must be based on synthesis as the premise, and synthesis should be the ultimate goal. Designs that do not consider synthesis are incomplete and unreasonable; Second, the synthesis is composed of multiple small synthesis, so the analysis process needs to inspect each part of the circuit separately, and then conduct an overall evaluation; third, only after a sufficient analysis of the electronic circuit can the synthesis be performed. Based on analysis, synthesis without analysis will inevitably add subjective components, which will bring deviations to the design of electronic circuits.2. Functional principle: complex large circuits can be divided into smaller circuit subsystems with different levels. When designing, larger-scale circuits should be refined first and divided into subsystems with independent functions. , and then use it as a functional module, determine the function type of each module and realize the functional requirements of each module, then select the specific circuit, determine how to select the appropriate electronic components, determine the use parameters of each component, and finally realize the design of the circuit subsystem Finish.3. The principle of optimization: The principle of optimization is a basic principle of electronic circuit design. Because of the defects of the electronic components themselves or some problems in the mutual cooperation of electronic components and functional modules, the functions of the electronic circuits cannot be fully realized, which requires certain design principles, design methods, and design steps. , starting from the adjustment of each component or each functional module, through calculation, the optimized parameter index is obtained, and the related components or modules are adjusted according to the calculation results, so that the entire circuit can achieve the goal of optimization.4. The principle of reliability and stability: Electronic circuits play a vital role in electronic equipment. The stability and reliability of electronic circuits will greatly affect the use and service life of electronic equipment. Electronic circuits The stability of the circuit is closely related to the form of the circuit and the selection of electronic components. In order to ensure the stability of the electronic circuit, the following principles should be followed: on the premise of ensuring the performance and function of the system, the structure of the electronic circuit should be simplified as much as possible. ; It is necessary to reasonably divide the functions of software and hardware, follow the principle of replacing hardware with software, and realize the complementarity of software and hardware; try to use digital circuits to replace analog circuits, because there are many factors that affect electronic circuits and are more complicated, and the time of occurrence and frequency are also unpredictable. Therefore, when designing, it is necessary to take effective protection measures against potential unstable factors. Anti-jamming technology or fault-tolerant technology are often used to prevent or reduce the circuit due to Interference caused by unstable factors.5. The principle of performance and price ratio: In the context of today's competition in the electronics industry, electronic products are required to have a short development and design cycle, and to ensure that the product has excellent performance and stability during use. Therefore, in order to improve the competitiveness of enterprises, the economy, advancement and operability of products must be guaranteed in the design of electronic products.2. Design method of electronic circuit1. Hierarchical design methodElectronic circuit design can generally be divided into three levels: the first level is the top level, which is oriented to the entire system when designing, and is a description of the overall function of the system; the second level is the middle level, which is oriented to the circuit level when designing; The third layer is the bottom layer, which faces the physical realization level when designing, and is the smallest design unit. There is no requirement for the specific design sequence, and it can be freely developed by the staff.2. Incremental design methodThe progressive design method is suitable for application-type circuits. When designing, it is necessary to understand the specific requirements first, then design the drawings, then analyze the working principle on the basis of the drawings, and design the basic circuit units. Debug and optimize the design of the basic circuit unit, and finally realize the design of the entire circuit.3. Hardware description language design methodThe hardware description language design method is a relatively advanced circuit design method, and its essence is electronic design automation. When using this method for design, it is first necessary to analyze the requirements of the project, and then formulate an overall plan that can meet the requirements. Then design the electronic circuit according to the overall plan, and test the rationality and scientificity of the circuit design through simulation. Finally, combine the basic circuits, and then perform unified adjustment and optimization, and finally achieve a more reasonable circuit design.4. Optimal design methodThere are many types of electronic products, and the circuit design methods are also various, and it is difficult to adjust circuits such as integrated circuits after they are manufactured. Therefore, when designing circuits, attention should be paid to precision control. Computer assistance can be used. The program applicable to this circuit realizes the optimization of each parameter of the circuit and completes the design of the circuit.3. Circuit design steps(1) Clarify the design requirements of the circuit: There are various forms of circuit design. When designing, it is first necessary to clarify the type of electronic product, then determine the design requirements of the circuit, and design the circuit according to the requirements.(2) Design the schematic diagram of the circuit: After clarifying the design requirements of the electronic circuit, it is necessary to design the schematic diagram of the circuit.(3) Check the circuit and select components: After completing the design of the circuit schematic diagram, it is necessary to check the rationality of the schematic diagram, examine its output power and signal voltage method multiples, and determine whether it meets the basic requirements of the circuit design. After the checking and calculation work is completed, it is necessary to select the components required for the circuit, focusing on the maximum power and signal current that the components can withstand to ensure the rationality of the selection.The above are the principles and methods of electronic circuit design introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad, including MCU, voice IC, Bluetooth IC and modules, wifi modules. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS solutions, the development of Bluetooth audio, the development of children's toys, and the development of electronic education products.
07-10
2021
With the development of computer technology, the application fields of embedded systems are constantly expanding, ranging from automatic navigation systems of space shuttles to mobile phones and smart home appliances. Embedded system is a typical hybrid system of software and hardware, and current products generally include embedded microprocessor and corresponding control software.1. Introduction to the collaborative development of embedded systems and hardware and softwareEarly microprocessors were both 4-bit and 8-bit. With the continuous development of manufacturing technology, integrated 8-bit microcontrollers began to appear, and 16-bit microprocessors began to be used in more complex embedded systems, 32-bit structured devices and highly integrated microcontrollers gradually occupied market for high-end applications. Still, more powerful microprocessors did not replace earlier microprocessors, but simply gave embedded system designers a wider range of choices in choosing the right microprocessor based on functionality, features, availability, and price. processor products.In the early days, due to the single function of the system, the embedded software part was composed of codes independently designed by the manufacturer, so it was very simple. However, with the expansion of applications, the system becomes more and more complex, especially for high-end embedded microprocessor systems, multi-task models are widely used in software development, and many manufacturers also choose third-party commercial embedded real-time operating system products ( RTOS). The hardware resource environment in embedded systems is generally harsh, and the memory is generally not large. To complete complex functions under such tight resources, it is required that the software part of the embedded system must be as compact, stable and efficient as possible.2.The general method of software and hardware joint designThe software-hardware joint design method is proposed in the design process of the software-hardware hybrid digital system, aiming at the defect that the traditional design method separates the software and hardware development process. It means that the software and hardware use a unified design method and adopt a consistent Design tools for synthesis, verification, and simulation of design methods.The main steps of the software-hardware joint design are as follows: (1) System-level modeling description: build a complete system description to verify the behavior of the system without considering the implementation details, driving functional verification and hardware-software partition; (2) Combined hardware and software synthesis: including software and hardware partitioning and scheduling, constrained code generation, hardware and interface synthesis. (3) Software-hardware joint simulation, debugging and verification: Model the behavior of the system on the basis of the known behavior of software and hardware components, and verify the function of the system and evaluate the performance of the system.3. The application and development of software and hardware joint design methodAs mentioned earlier, an embedded system is a typical mixed system of hardware and software. At the beginning of the design, the designer needs to divide the system into hardware and software. The software and hardware here can be not only separate components, but also different abstraction levels of the same physical component. In both cases, the interdependencies between hardware and software lead to compromises in their respective implementation methods. At the same time, due to the great changes in the application requirements of embedded systems and the strong requirements for performance, real-time and flexibility, the initial design and division have a great impact on the design quality of the entire system; and due to the complexity of high-end products, many problems in the It will be exposed during the software and hardware integration process. All of these put forward the demand for joint synthesis and joint simulation. Therefore, it is necessary and urgent to introduce the method of joint design of software and hardware in the design of embedded systems.From the perspective of methodology, the joint design of software and hardware of embedded systems follows the above general methods and rules. With the development of microelectronics technology and embedded system itself, its design method will show some new characteristics.1. Software and hardware divisionLike the design of other mixed hardware and software systems, hardware and software partitioning is a very critical step in embedded system design. How to improve the efficiency of the partition algorithm and reduce the time complexity is the focus of research. Existing research results have improved the effectiveness of partitioning from many aspects. In addition to the most basic simulated annealing algorithm, methods based on compiler guidance, graph-based minimum cost algorithm, software and hardware pipeline, and interactive partitioning have also been proposed.2. The impact of standardization and high integration of commercial components on software and hardware designWith the development of microelectronics technology, more standard commercial components are put on the market, while highly integrated devices reduce the number of chips. Many designers are now more than happy to use microprocessors and microcontrollers that incorporate more functionality. Correspondingly, the design of the software has also changed. The workload of software development has increased dramatically, often reaching 70% to 80% of all work. In order to shorten the development cycle, along with the trend of hardware standardization, the software content has also shifted from self-designed to using products with intellectual property rights as much as possible. Utilizing portable code and standard real-time operating system has become the direction of designing embedded system application software. Of course, for embedded system developers, decisions involving the integration of standard components and the selection of intellectual property are also complex decisions that must be faced now and in the future.From the above changes, it can be seen that with the increasing abundance of standardized software and hardware components, the granularity of software and hardware division in embedded system design increases, so that the system description is relatively clear, the software and hardware design work is significantly simplified, and more emphasis is placed on interface design. And overall performance, design space flexibility and diversity are greatly increased. These changes have put forward new requirements for existing design methods and related technologies, such as how to refine the partition algorithm so that it does not need to consider unnecessary details, and further improve the abstraction level of joint simulation and verification, shorten the development cycle, etc. question.3. "United" and "decentralized" in embedded system designIn the traditional design method, the software design often lags behind the hardware, and the joint simulation technology and virtual prototype technology adopted in the software-hardware joint design method are just to make up for this gap. Therefore, software and hardware design engineers work together to become A trend of development. Through co-design, and specifically co-verification techniques, software engineers are able to test on real hardware as early as possible, and hardware engineers are able to verify their designs early in the prototyping cycle. To achieve this goal, an integrated development environment must be provided, in which software and hardware modeling, joint simulation and evaluation can be completed. Some solutions exist, such as instruction set emulators and standard low-cost commercial evaluation boards. In addition, low-cost master-target computer connection technology has been widely used.Another feature of the development of embedded systems is that more and more developers are needed. In order to effectively manage the development team, some proprietary technologies must be encapsulated so that they can be used by non-specialists in a safe, reliable and straightforward manner. Therefore, object-oriented thinking should also be introduced in the design of embedded systems. In many large companies, the software development team is not simply growing, but is being dispersed, with members working in different regions or countries. This situation has led to the emergence of "Technology Centers" where the use of "Software Parts" is becoming more and more realistic.4. Brief introduction of software and hardware collaboration in SOPC embedded systemWith the rapid development of semiconductor technology, the scale of integrated circuits continues to increase, and the emergence of large-scale programmable logic devices makes it possible to integrate the entire system on a single chip and realize in-system programming. This is the on-chip programmable system SOPC (System on a Programmable Chip). It supports parallel SOPC technology with flexible design methods: it can be cut, expanded, and upgraded, and it has in-system programmable functions of software and hardware.FPGA (Field-Programmable Gate Array, Field Programmable Gate Array)-based SOPC design has shown rapid growth in the semiconductor field in recent years and has become the first choice for system-level designers. However, as the system scale continues to The increase makes the design of the whole system very difficult, and the system development cycle is getting longer and longer, and today's embedded electronic products are very sensitive to the system development cycle, so a fast and efficient design method is worth exploring and research question. For these problems in embedded system design, the researchers proposed a new method of software-hardware co-design.SOPC system is a complex of software and hardware. Many functional modules in the system can be completed by hardware or software. Hardware implementation is characterized by high performance and speed, but high cost and poor flexibility; while software implementation is characterized by good flexibility and low cost, but poor performance. Therefore, how to take into account the system's function and performance (such as power consumption, cost, area, etc.) requirements in the design and implementation process so that they can achieve an optimal combination is the main problem to be solved by the software-hardware co-design method.5. Traditional electronic design methodsAt present, domestic and foreign enterprises generally adopt the traditional embedded system design method. The steps of this method are to first define the requirements description of the system, and then divide the software and hardware of the system. After the division is completed, the hardware and software design will be carried out separately. If errors are found in the hardware and software design, it will directly return to the software and hardware. division.The disadvantages of this approach are as follows:1) The parallelism between software design and hardware design of the system is low, and the design cycle is long. This design flow uses the hardware design first, followed by the software design. That is, after the hardware is designed, the software is designed on the basis of the hardware. In this serialized design method, when the hardware design is completed and the software is debugged, if an error is found in the hardware design, it will cost a lot of manpower and material resources to correct the error. The software and hardware of the system cannot be co-verified, which leads to a substantial increase in the number of repetitive design tasks and increases the design cost.2) The level of system design is low. System-level design relies on manual work. The large-scale design exceeds the ability of designers. The development process of system software and hardware lacks communication and coordination, resulting in a decrease in design efficiency.3) It does not support customized embedded processors, which are fixed modules and do not support design reusability.6. Characteristics of software and hardware co-design methodBecause of these shortcomings of traditional embedded system design methods, people began to explore new design methods to adapt to the high-speed development of embedded systems, this method is the software-hardware co-design method. As early as 1993, it has become a research direction and hotspot in the field of system-level design in embedded systems.The characteristics of the software-hardware co-design method are as follows:1) The software-hardware collaborative design technology adopts the idea of parallel design and collaborative design, which shortens the design and development cycle and greatly improves the design efficiency.2) Software-hardware collaborative design adopts a unified tool and representation method, reasonably divides software and hardware, allocates system functions reasonably, weighs cost, performance, power consumption and other aspects, and obtains the most optimized design as much as possible.3) Software-hardware co-design adopts the method of software-hardware co-simulation to conduct global design verification on the whole system.Software-hardware co-design has greatly improved the abstraction level of the design, and broadened the coverage of the design. It can make the design of embedded systems more efficient and faster. Software-hardware co-design is a new design method and idea. It is not just a design technology, it is to link the design of software and hardware, so as to avoid the premature independence of these two parts of design. Software-hardware co-design technology is now in the development stage, and many theories are not yet mature. However, this technology has greatly improved the design efficiency of embedded systems, and has great research value and social significance.7. The development process of software and hardware co-designThe main tasks of embedded system design include: system task description, system modeling, used to realize the functional requirements of the system; appropriate software and hardware division of the system to meet performance requirements, reduce cost and power consumption; system synergy And simulate the system implementation and specification. The purpose of software-hardware co-design is to make the various influencing factors of the system coordinate with each other to complete the system function.1. System task descriptionTo design an SOPC system, the first step is to clarify the requirements of the system, that is, the performance of the system and the functions to be realized, and then to model the system. The models of SOPC system mainly include finite state machine model, data flow graph model, task flow graph model, discrete event model, Petri net model and so on. Establish a common system function description method for software and hardware to solve the problem of unified description of the system. At present, the method of system description language is usually used. In this way, after the software and hardware are divided, it can be compiled and mapped into a hardware description language and a software implementation language, which provides a strong guarantee for the system's software and hardware to work together.2. System hardware and software divisionIn the traditional embedded design method, the development process of software and hardware is separated, and there is a lack of communication between them. This makes the design efficiency of the system very low. Aiming at this shortcoming, a method of software-hardware co-design is proposed. In this method, the division of software-hardware system is one of the key steps in software-hardware co-design. The hardware implementation part of the system has a decisive effect on the performance of the system. Usually, the hardware implementation part is faster, but cost control also plays a decisive role in this part. The software implementation part of the system usually has great flexibility, which determines the flexibility of the system configuration, but it takes a certain amount of FPGA logic units and takes a certain amount of time. As shown in Table 1. Table 1 points out whether the system is implemented by hardware or software, which affects the chip area, power consumption, performance, and manpower and time resource requirements. A reasonable software-hardware co-design scheme plays an important role in the design of embedded systems. Reasonable division of software and hardware, on the basis of satisfying system functions, can give full play to the characteristics of fast hardware processing and flexible software control.Influence factors of software and hardware design on the systemThe result of the software and hardware division is to improve the system speed, reduce the area, reduce the cost and reduce the power consumption. However, software and hardware partitioning is usually a traditional problem. Since the partitioning problem itself is very difficult, and SOPC has a huge search space, the situation is even more severe. Today's automatic partitioning algorithms still cannot replace experienced designers. The method of division basically starts from two aspects: one is software-oriented, and the requirements of timing are met from software to hardware; the other is hardware-oriented, and costs are reduced from hardware to software. When dividing, it is necessary to consider various factors such as the architecture, granularity, and cost of hardware and software implementation of the entire target system. After the division is completed, the divided interface of the software and hardware system is generated, which is provided to the software and hardware for communication, verification and testing. Commonly used software and hardware cooperative partition algorithms include simulated annealing algorithm and genetic algorithm. The genetic algorithm and the simulated annealing algorithm are relatively complementary. The genetic annealing algorithm formed by combining the two algorithms will inherit the advantages of the two, and the performance in the division of software and hardware is very good. Now this intelligent algorithm is a software It is a research hotspot in the field of hardware partitioning algorithm.3. Software and hardware synergy synthesis stepsAfter the software and hardware division is completed, the design and implementation of the software system and hardware system are carried out respectively. The stage of designing the partitioned system is called synthesis. The main task of this step is to convert the description of the partitioned system into a synthesizable hardware description and a compilable software program. Build a design translation process that includes implementation structure descriptions for software and hardware. For example, the divided description can be translated into Verilog HDL (hardware module) and C (software module). Software-hardware co-synthesis consists of the following three steps:1) Allocation of processing units, which determines which processors, DSPs, and special hardware and other architecture-level units of the embedded system are composed;2) Task assignment, which determines which functions in the system are implemented by the hardware processing unit, and which functions are implemented by the processor using software;3) Task scheduling, which determines the start time and execution sequence of tasks assigned to each processing unit.4. Software and hardware co-simulationSoftware-hardware co-simulation verification is an evaluation stage for the correctness of the entire system design and the determination of performance indicators. In each stage of embedded system design, simulation verification can be divided into system-level simulation, behavior-level simulation, register transfer level (RTL level) simulation and gate-level simulation. System-level simulation is generally used to evaluate the overall function of the system and verify the correctness of the algorithm; behavior-level simulation can simulate the designed logic, but does not consider the characteristics of the target device, such as capacity, delay, etc., behavior Level simulation can use advanced statements, such as error statements, file read and write statements, floating point format, etc., but these statements are usually not implemented in the target device; register transfer level simulation checks whether the logic functions of each module are correct, and then , integrate the simulated modules together, and perform functional simulation of the entire system. The simulation at this stage does not include the time information of the hardware circuit, so the design can only be verified from the logic function; the gate-level simulation will use Synthesize the gate-level netlist generated after software synthesis or the gate-level model generated after implementation for simulation, without adding the simulation of the delay file.Typical hardware-software co-simulation is usually run under Quartus II under the development environment of CPLD or FPGA. If some resources such as the IP core used by the system have been independently verified, the simulation verification of its gate level or RTL level can be omitted.8.Embedded system hardware and software collaborative design summaryThe software-hardware collaborative design method based on SOPC can grasp the complex system macroscopically, overcome the shortcomings of traditional design methods, fully tap the synergy between software and hardware, correctly divide the software and hardware of the system, and select the appropriate IP, establish a system design platform and verification platform, promote parallel development of software and hardware, reduce design risk, shorten the development cycle, and play an important role in the design of embedded systems. With the support of logic design and EDA tools, SOPC-based software-hardware co-design technology plays an increasingly important role in the design of embedded application systems, and will be the core technology in the field of IP-SOPC design in the future.Embedded system has strong vitality, broad market and far-reaching application prospect make its development change with each passing day. In order to develop various embedded applications more quickly and effectively, it is of great academic and commercial value to study software-hardware co-design methods. Technologies such as system modeling, software and hardware division, and virtual prototypes are still key issues in embedded system design, and are constantly supplemented and developed with the development of microelectronics technology and computing technology.The above is the joint design method of software and hardware for embedded systems introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad, including MCU, voice IC, Bluetooth IC and modules, wifi modules. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS solutions, the development of Bluetooth audio, the development of children's toys, and the development of electronic education products.
07-09
2021
Electronic products have penetrated into people's lives and become an irreplaceable and important life tool. Based on the needs of the times, the requirements for electronic products are getting higher and higher. How to speed up the improvement of the practicability of electronic products and how to improve their core in the market Competitiveness has become an important issue that practitioners in the electronic product industry need to solve urgently. But at the same time, the practicability of electronic products is closely related to its hardware design. Therefore, the exploration of the practicability of electronic products requires an in-depth analysis from the hardware design of electronic products.1. Analysis of hardware design of electronic productsFor the market and users of electronic products, the competitive conditions can be roughly divided into hardware design content and external design image. Based on a certain premise, hardware design conditions often directly determine the practical value of electronic products, and when users choose electronic products, they also choose products with higher cost performance among different hardware designs based on personal needs. This shows that hardware design is very important for electronic products. Product development has played a crucial role.In our country, the hardware design of electronic products can often be directly linked to the production cost of the enterprise. The impact of changes in market competition. Taking mobile phones as an example, when two mobile phones are comparable in external conditions, users will often make purchase decisions based on the performance of the mobile phone, and high-quality performance is the guarantee of high sales, and high-quality performance can also promote other manufacturers. Improve your own design to strive for more market share, thus forming a healthy competitive environment.2. The process of hardware designCombined with the above analysis of the importance of hardware design for electronic products, some other questions we need to understand are, what is the specific process of hardware design? What factors make up hardware design that make it such an important part? In view of the above problems, this article will conduct an in-depth analysis by introducing three aspects: preparatory work, schematic diagram drawing, PCB diagram drawing and related component installation.1. Preparatory work on hardware designIf the quality of hardware design is the key to the formation of core competitiveness of electronic products in the market, then the preparatory work for hardware design of electronic products is an important basis for the development of work for hardware design. The preparatory work of the hardware design is mainly related to project planning and corresponding preparatory work, that is, the project is divided into several areas according to different categories, and different areas are set up according to modules. It is worth noting that the components or other devices selected in the module erection should be based on the drawings, and the mainstream components with a longer service life and longer service life should be used as much as possible. After the erection is completed according to the drawings, the test should be carried out to ensure normal operation, and relevant Record the work for future review or return receipt. The importance of preparatory work in the early stage is not only reflected in its basicity, but also in that it needs to serve the follow-up work well. The preparatory work in the early stage directly determines whether the later work can be carried out normally, so it is extremely important.2. About the drawing work of the schematic diagramThe packaging of components is based on the drawing of the schematic diagram, and the drawing of the schematic diagram needs to rely on the preparatory work in the early stage, which is interlocking. When drawing the schematic diagram, first draw the schematic diagram of the functional block according to the different circuits and components in different areas, then mark it, and start packaging after confirming that it is correct. The drawing of the schematic diagram is the core work of the hardware design of electronic products, and it also plays a role as a link between the past and the future. Based on the drawing of the schematic diagram, it is possible to analyze the entire design, find problems and mistakes in time and modify them. It can be said that the drawing of the schematic diagram It directly reflects whether the functionality of the hardware design of electronic products is good or not, and needs to be highly valued.3. About drawing PCB diagramThe drawing of the PCB diagram is the last step in the hardware design process, and it is also the final step based on the improvement of the previous work. After completing the drawing of the schematic diagram, the component package in the schematic diagram is imported into the PCB diagram, and then the components are placed.In this process, special attention should be paid to the placement order of components, the connection between components, and the actual related layout. After ensuring that the drawing size and position are accurate, the hardware design work is completed. It is worth mentioning that it is necessary to try to avoid overlapping in the connection relationship, which will directly affect the design requirements of the hardware design. Different electronic products have different requirements, and as the last step, it should be checked as a whole to avoid omissions.3. Application of electronic product hardware designMobile phones, computers, cameras and other electronic products have become an inseparable part of people's lives. The application and practicality of electronic product hardware design can bring users the most intuitive feeling. It is not difficult to infer that the sales of the product itself will also Therefore, how to improve the practicability of products based on the application of hardware design has become a key issue.1. Miniature electronic devicesRegarding the discussion of microelectronic devices, the author takes integrated circuits as an example. Integrated circuits are relatively small in size, light in weight, low in cost, and simple in structure. They meet the low energy consumption and high reliability requirements of current electronic products, and are one of the development directions of electronic products based on the development of the times. As far as integrated circuits are concerned, they can be seen not only in civilian electronic products, such as computers, televisions, etc., but also in military and communication fields. Due to the advantages and distribution density of integrated circuits, the equipment's Stability has come a long way, so it stands out both in terms of advancing electronic components and increasing the usability of products.2. Application of memory devicesThe application of the memory device actually refers to the application of the memory. The memory is an important part of the computer. The data can be stored and extracted through the memory, and then the data can be used. Memory is not only used in computers. Based on the development needs of the current era, almost all electronic products will use memory. So far, memory devices are roughly divided into two categories. One is ROM-based memory, which is for the system The program performs storage functions, and the other type is data-based storage.4. Design for improving the practicability of electronic productsAfter a brief introduction to the application of hardware design in electronic products, it is necessary to explore how to improve the practicability of the product. Taking mobile phones as an example, during the use of mobile phones, the practicability of mobile phones is directly related to the hardware design of mobile phones. Such as: product wear and tear, that is, the service life and fluency problems in the service life, and functional wear and tear, that is, to ensure its timely maintenance performance when there is a problem with the product components during use. Based on these two points, the continuous improvement of the practicality of electronic products can be fully guaranteed.1. Component wear and fluencyDuring the use of electronic products, it is inevitable that due to the age of use, frequency of use, use environment or other factors, the components of electronic products will be worn out. The wear and tear of components may directly damage the smoothness of use of electronic products or increase their failure. probability, thereby reducing product practicability. Therefore, in the hardware design of electronic products, the first thing to consider based on practicability is the wear and tear of the hardware design of electronic products, and evaluate the wear and tear of the current components through the existing loss values, and carry out the overall mechanism design on this basis Adjust and design components that can replace existing components and reduce loss values, and bring good experience to users on the basis of improving practicability.Taking mobile phones as an example, after one to two years of use, there will be problems such as slow start-up of clicking software, slow switching of screens, or unsmooth operation processes. As a result, the replacement speed of mobile phones is accelerated. In the process of being eliminated too quickly, the ultimate loss is the enterprise itself. Only a good user experience can retain users for a long time, and wear and tear are inevitable. Reduce the loss value so that wear and tear will appear later or parts can be used. Replacement is the key. Only by fundamentally satisfying the practical needs of users for products can enterprises win market reputation and achieve long-term development.2. Repairability of components based on wear and tearTo put it simply, maintainability means that when the components in electronic products are worn out, they can be repaired and replaced in time to continue the use of electronic products and improve the practicability of the products. When enterprises design the hardware of electronic products, they must take this into consideration. For hardware design components, choose a combination of components that are portable or can be integrated as much as possible, and improve the convenience of electronic product functions under hardware design. After the hardware design, appearance and fluency of electronic products reach a certain standard, we provide maintenance services for component wear and tear caused by long-term use of electronic products.Taking a computer as an example, during the use of the computer year after year, it is inevitable that hardware components will be worn out. When the problem occurs, the user cannot replace or use other computers based on the importance of the files in the computer memory. The computer is repaired so that the computer can continue to provide services, and the component loss is generally caused by the aging of the components. During the maintenance process, attention should be paid to selecting the appropriate electronic components that can be replaced, which must conform to the design of the original electronic product hardware design The concept must also meet the needs of the continuous use of current electronic products, and avoid problems that may occur after replacing electronic components, such as long-term overheating of the fuselage and serious decline in product fluency.5. Summary of hardware development technology for electronic productsNo matter how convenient and rapid the development of technology is, the practicability of electronic products is always the core competitiveness of electronic products. Only by improving the practicability of products and meeting the needs of users in many ways can we occupy a place in the electronic product market. As an enterprise, we should not only see the petty profits in front of us, we must start to provide after-sales protection of the practicability of electronic products in terms of component wear and maintenance, and at the same time, fully consider all aspects in the original electronic product hardware design. Factors, fundamentally improve its practicality. It is hoped that the relevant workers can continue to explore in depth on this basis, and put forward more constructive suggestions and opinions for improving the practicability of electronic products.The above are the details of hardware design technology of electronic products introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad, including MCU, voice IC, Bluetooth IC and modules, wifi modules. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS solutions, the development of Bluetooth audio, the development of children's toys, and the development of electronic education products.
07-08
2021
Intel Embedded Platform Hardware Design Process GuideWith the rapid development of technology, how to quickly provide complete solutions is becoming the main challenge for modern high-tech enterprises. This requires the development team to conduct detailed research and deeply understand the actual needs, and conduct demand analysis, such as product performance indicators, product function requirements, testing and certification requirements, project cost objectives, etc., to further clarify the design tasks. Intel's product line is relatively extensive. According to design tasks and requirements, learn platform materials for evaluation. When designing a reliable, reasonable, and economically feasible solution, special attention must be paid to the compliance of various functional parameters of the Intel platform with actual needs. For details, please refer to Intel product documentation.1. Intel Platform Documentation Terminology1.1 External Design Specification EDS (External Design Specification)This design document contains information on the use and implementation of the platform support reference design to help customers design products using Intel. Also includes performance metrics or design information for system designs using specific Intel components, as well as Intel processor cores, graphics, memory controllers, bus signal descriptions, system memory matching, number of bus interfaces, electrical characteristics, packaging information, clock distribution , the voltage requirements of the chip, and specific information such as power-on sequence and input/output interface.1.2 Platform Design Guide PDG (P1atformDeSignGuide)Design Guides contain information to support the use and implementation of reference designs to assist customers designing with Intel products. Also includes design information and design recommendations for PCB board layout and board-level system design using specific Intel components, specific to the wiring and routing recommendations for each interface of the CPU and chip, such as DDR topology, DMI, DDI, DSI , SATA, PCIe, USB, etc.; the Design Guide will also include design guidelines for power distribution and power-on sequence in the platform, as well as detailed specifications and requirements for PCB stacking, wiring, interfaces, equal lengths, and vias.1.3 Customer Reference Design Schematic CRB (Customer Reference Board Schematic)The customer reference board schematic diagram describes the characteristics of a complete Intel product, including the schematic design of a specific product customer reference board, which will connect the various bus interfaces of the Intel corresponding platform, and the system functions can be realized through debugging, including the system frame diagram , power supply scheme, clock, platform power-on sequence, power management, detailed schematic diagram implementation to specific component connections, etc.1.4 Customer Reference Design Layout Document (Customer Reference Board fi1e)The customer reference board layout file is a layout file designed for the target system. In one-to-one correspondence with the customer reference design schematic, use the reference customer reference board user guide, customer reference test plan, and customer reference system design.1.5 Platform layout checklist (Layout check 1ist)The layout checklist is an important part of reviewing the design guide and implementing a system layout design. It is used together with the relevant platform design guide from the overall situation to the details. Each specific bus interface has detailed requirements and instructions, such as high-speed bus Wiring, number of vias, clock distribution, characteristic impedance, length limit, etc. Check possible problem points to enhance the stability of the motherboard.1.6 Schematic design check listThe schematic diagram checklist is a list and list of items that need to be reviewed in the product design schematic diagram, the recommended design and guidance of the schematic diagram, and the wiring differences and problems between the self-examination and the CRB schematic diagram. Check the connection of the peripheral signals of the chip, the connection of the high-speed signal, the power supply status, the clock distribution, and the shielding precautions of the unused bus interface. It is often used in conjunction with the external design specification EDS in the schematic design.2. Intel project design process2.1 Intel project design preliminary preparationIn the early stage of actual project design, it is necessary to conduct demand analysis and clarify development tasks. Designers need to contact Intel's technical support engineers in time to understand the product roadmap, and discuss the chip solution of the platform based on the actual needs of the project; the types of debugging tools and use documents in the development and debugging phase, and clarify the project development plan and timetable; apply for Intel CRB simultaneously The reference design board is debugged and evaluated in advance to shorten the production and development cycle and obtain Intel's technical support and design resources in advance. Of course, in the process of referring to the characteristic indicators of EDS and other documents, it is also necessary to conduct preliminary product software implementation feasibility studies, such as discussing SW development and design with BIOS/OSV manufacturers, MCU implementation and system cooperation, and OS and driver function implementation. , the choice of system cooling scheme, etc. Combined with the project requirements, start to prepare design documents and design schemes. It is necessary to design the system architecture first, draw a system block diagram and discuss the implementation with relevant design departments, sort out the conceptual block diagram of power distribution, clock, power-on sequence, reset, interrupt, debugging, etc. , combined with the Intel platform customer reference design schematic diagram CRB, from device selection and unit scheme realization to the formulation of the overall scheme. It is necessary to refer to documents such as PDG, EDS, and CRB, and pay special attention to the operating voltage, operating frequency, system timing, and overall power consumption of the chip to meet the system design requirements.2.2 Intel hardware schematic diagram drawing stageIn the schematic diagram drawing stage, first refer to the Intel chip library file to ensure that the layout of the schematic diagram is clear and reasonable, and the layout is evenly arranged. Learn the descriptions of each group of signals in the EDS document: system memory, bus interface, electrical characteristics, and power-on sequence (this is the platform The important foundation of power-on design), consult relevant information from EDS, and refer to CRB to define the power-on sequence of the project platform according to the timing requirements of the main functional modules of the platform; secondly, combined with project functional requirements, refer to intel CRB Schematic design, pay special attention to power distribution, clock arrangement, high-speed signal connection, etc. After the first draft of the schematic is drawn, it needs to be carefully combined with Intel's schematic design check list to check for error-prone places, especially DDR, PCIe , USB, DDI and other high-speed signals; then, hardware developers need to discuss and prepare the BIOS/Boot loader program with SW colleagues in time, so as to make full preparations for the first version of proofing and trial production. Of course, selecting and drawing other components is also an important part, and it is necessary to fully consider the convenience of post-processing and production process and the substitution of components. You can apply for Intel technical support personnel to review the project schematic diagram at the same time. Combined with the inspection results, convene a schematic design team for final discussion and modification, and meet customer functional requirements such as function, performance, and redundancy design. Specs and standards and indicators of the Intel platform Conformity, and the manufacturability, debuggability, testability of the factory, etc., the final modification is determined.2.3 Intel PCB layout design stageIn the layout and PCB design stage, it is necessary to cooperate with the organization/ID/EMI/RF/Power/thermal team in time to discuss the placement of the main chips to meet the design requirements of the overall project plan. First, combined with the PCB stack structure, calculate whether the width of the PCB traces of each group of high-speed signals can be smooth, discuss the position of the power supply device and the placement of sensitive components, and generate a formal design document: pay attention to the I/0 interface, temperature, and clock elements. The focus of the discussion on device location and height-limited area is second. When drawing the PCB layout, it is necessary to choose a reasonable stack-up design, arrange the main components evenly, and make the high-speed signal wiring smooth; special attention should be paid to the shielding of interference sources and sensitive signals. The power supply of functional modules should be relatively isolated; pay attention to the wiring distribution of high-speed signals and power supplies to avoid mutual interference; reasonably plan the layout of power supply modules and power supply distribution paths, and increase the width of power supply lines as much as possible according to the current size of the printed circuit board. reduce loop resistance. The length of high-speed signal traces must comply with the Intel specification, and the actual length on the PCB needs to be filled in to check the trace length in the equal length table. Reasonably plan the reference plane and power plane of high-speed signals, pay special attention to the wiring of high-speed signals such as DDR, DMI, DDI, DSI, SATA, PCIE, USB, etc., to avoid signal interference and interference effects; increase the gap between high-speed signals and analog signals Distance, increasing the distance between signal lines as much as possible can effectively reduce capacitive crosstalk; the loop area should be minimized to reduce inductive crosstalk. In the design of the ground wire, pay attention to the noise interference of the digital ground to the analog ground, the digital ground and the analog ground can be separated, the ground wire should be as thick as possible, and the ground wire of the digital circuit system forms a closed loop, which can improve the anti-noise ability. Pay attention to the signal impedance matching of signal integrity, uniform line width, and reasonable line spacing; avoid impedance discontinuity of transmission lines, reduce the use of stub lines, etc. Sensitive signal traces such as analog signals, clock signals, and temperature signals should be kept as short as possible and kept away from interference sources such as power supplies. The number and distribution of vias are reasonable, especially the number of vias for high-speed signals does not exceed the requirements, you can refer to CRB layout file, layout check list and PDG. Comply with the Intel reference design document PDG, so that the power distribution is reasonable, the clock routing is appropriate, and the high-speed signals such as DDR are not affected or affected; in the later stage, carefully check one by one with the layout checklist, especially high-speed signals, etc. Length, power supply, EMI countermeasures and other parts. When approaching the early stage of board release, Intel professional engineers can be invited to conduct simultaneous inspections. After receiving feedback results, a layout inspection meeting will be held in a timely manner. After discussions and revisions, formal design documents will be produced for release and production.2.4 Intel PCB production stageDuring PCB production, it is necessary to check the bill of materials synchronously, coordinate the trial production schedule, prepare the first article test plan, debug tool software, and debug equipment. When the first PCB is received, first conduct the power-related open-short circuit test, and then conduct the power-on test after confirming that it is correct, focusing on checking the power supply timing, clock, reset and other signals, and comparing the power-on timing requirements in the Intel platform EDS, software and hardware development The personnel timely adjust and solve the design that does not meet the requirements of the spec. After the power on is completed, the functional test report and signal integrity test report need to be completed, and then the system power consumption and power quality test, the compatibility of the main components and the system stability are performed. Testing; generate formal test reports and change documents for subsequent traceability of related issues. If necessary, you can seek help from Intel platform application engineers in debugging and verifying the motherboard.2.5 Intel hardware platform debugging stageAccording to the test results after the first trial production, modify the schematic diagram and layout design, further check the accuracy of the upper part of the material, simultaneously solve the problems related to factory production and functional testing, and form a design document: after the second trial production, further verify the system Functional stability, such as high and low temperature, aging, running for a long time and switching on and off multiple times, etc.; solve the concentration problems found by the relevant testing department in a timely manner. After the third boarding, the number of units and the number of times to verify the stability of the system are multiple times, and it is also necessary to improve the production yield before the final mass production of the product, such as simplifying the design, using the arrangement to reduce the number of parts, etc. During the testing and testing process, the concentration problems encountered were resolved until mass production and shipment began.SummarizeThe purpose of Intel's embedded platform design is to make the system equipment achieve the expected functions, and the system can run more stably. This article focuses on the functions and connotations of Intel's main design documents, and solves the problem of X86 development engineers in the process of designing embedded platforms. All kinds of confusion encountered and guidance schemes are given, which can be used in most of the system hardware design process to achieve better project results, which can shorten the time to market and development resources. Of course, in the modern fast-paced product development cycle, the requirements of various projects are also very different. We can choose the key development direction in a targeted manner based on the actual situation.The above is the guidance of the Intel embedded platform hardware design process introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, Bluetooth IC and module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
07-07
2021
The research object of this paper is mainly the circuit board, and the specific maintenance measures can be known through the detailed diagnosis of the common problems of the circuit board. Different fault problems should adopt different maintenance strategies accordingly. In fact, through a comprehensive analysis of electronic equipment circuit board failures, we can clearly understand that timely operation and maintenance of equipment is very necessary. With the help of the following measures, the quality of circuit board work can be effectively improved, and its safety and reliability can also be steadily improved. First, the diagnosis methods in the case of circuit board failure are summarized, including measurement method, elimination method and replacement method. Secondly, the specific maintenance strategies are summarized and summarized, including cleaning and rust removal measures, detecting fuses, detecting components, and finding corrosion points, etc.The innovation of electronic equipment is inseparable from the development of advanced science and technology. With the support of technology, there are various forms of electronic equipment circuit boards, not only in the form of double-sided boards but also in the form of multi-layer boards. In fact, the scientific integration of electrical equipment layout and the mass production of fixed circuits will be affected by its different forms, which have very special practical value. Today's circuit system construction is becoming more and more diversified and intelligent, and it is conceivable that the problem of circuit board failure will gradually increase. In order to ensure that related equipment can serve enterprises or individuals more efficiently, it is necessary to strengthen the operation and maintenance efficiency of vehicles in a timely manner, and solve existing failure problems in a timely manner.1. Overview of common circuit board fault diagnosis methodsWhether it is to replace the circuit board of electronic equipment or perform professional maintenance on it, before taking specific measures, it is first necessary to judge the integrity of the structure in time and accurately judge the fault factors related to the equipment. Therefore, this article summarizes three common and efficient methods of diagnosing faults, and presents their working principles in time.1. About the working principle of the measurement methodWhen carrying out the measurement method, it is first necessary to use a multimeter device to measure the output voltage parameters of the relevant device. On this basis, its failure can be evaluated and determined. Of course, fault diagnosis workers must have a very deep understanding of machinery and equipment, be able to master the corresponding basic knowledge, especially have a very clear understanding of the value range of the device output voltage parameters. After summarizing the practical experience, we can know two different value methods: first, the value range is clarified according to the detailed data provided by the manufacturer. The second is to perform accurate measurements when using the board for the first time, and then use it as baseline data.2. About the working principle of the exclusion methodThe basic principle of the elimination method is now summarized as follows: relevant workers can further determine the main cause of the fault phenomenon based on the operating principle of the circuit board device, and then can adopt simple to complex working principles to eliminate the fault problems one by one. Often times, board failures are found in the last components tested. In fact, the specific fault diagnosis method is based on the path from the mechanical failure of the circuit board connection to the mechanical failure of the circuit board accessory device. Practice has proved that this method of troubleshooting has a very efficient effect. In comparison, the exclusion method has many advantages, such as strong controllability and operability.3. About the working principle of the substitution methodThe so-called replacement method is to replace the circuit board in the same state, so as to compare and detect the fault. In order to achieve a certain economic effect, the common diagnostic work is as follows: Assume that when the mechanical equipment of the same model is running, if it is necessary to diagnose the problem of the circuit board of a certain mechanical equipment, it is necessary to distinguish the circuit board from the normal operation. Replacement of mechanical equipment. Under this operation, assuming that the failure problem still exists after the replacement operation is implemented, it can be concluded that the circuit board has a failure problem at this time.2. Important measures for efficiently repairing circuit board failures1. Timely implement the work content of cleaning and derustingIn fact, it is unavoidable that some substances or adsorptive impurities appear in the circuit board device. However, when these adsorptive substances appear in the circuit board device, it will limit the heat dissipation of related components, and even make the circuit The board is paralyzed. If the circuit board is severely damaged, it will be difficult for the device to continue to operate. Especially when the adhesive dust appears at the corner of the chip, it will make the quality of the chip components not high, and even cause the problem of short circuit on the circuit board. It can be seen that it is very necessary to carry out cleaning and derusting maintenance on the circuit board in time to reduce the interference of adhesive dust on the equipment in time.2. Scientific detection of fuse deviceFor safety reasons, fuse parts are installed in the circuit board assembly. In this way, even when the circuit board passes through high current, it can still protect the components and prevent the components from being damaged. That is to say, during detection, it is also necessary to detect the fuses in the circuit board device in time to grasp the damage status of the fuses. When there is a problem that the fuse is damaged, it must be replaced in time, that is, the fuse of the same type should be used.3. Research on the problem of component damageBefore performing circuit board repair work, the different components must be carefully observed and evaluated based on the observations. Usually there are three types of failures: the first is the crack problem, that is, the circuit board component capacitance becomes larger, and cracks and other phenomena exist at the same time; the second is that the triode is burned, showing a penetrating state. The third is that the resistance element is blown, which cannot achieve timely protection. In response to this phenomenon, it is necessary to replace the device of the same model in time to solve the problem of circuit board failure.4. Detect corrosion spots and virtual welding problemsDue to the existence of manufacturing process factors, it will have a great impact on the internal circuit board device of some mechanical equipment. After a period of operation, there will be a certain degree of virtual welding at the corners of some components. In addition, the circuit board assembly also suffers from corrosion problems under the influence of a humid environment. In fact, the humid environment is not conducive to the normal operation of the circuit board device of electronic equipment, so the operating efficiency of some of its components will be greatly affected. In view of the above problems, it is necessary to implement false welding measures at the location of the fault. At the same time, the maintenance method of secondary connection can also be adopted according to the actual conditions.Nowadays, the level of science and technology in our country has been significantly improved, and there are more and more talents with advanced skills. It can be seen that the speed of my country's modernization development will have a very gratifying improvement. Since the operation effect of the power system is closely related to people's daily life, relevant departments need to strengthen the control of electronic equipment in a timely manner, give full play to the skills and rationale of advanced talents, and improve the effect of circuit board maintenance.The above is the diagnosis and maintenance technology of the circuit board introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad, including MCU, voice IC, Bluetooth IC and modules, wifi modules. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS solutions, the development of Bluetooth audio, the development of children's toys, and the development of electronic education products.
07-06
2021
Circuit-level simulation analyzes the performance of circuits composed of electronic components, including logic simulation of digital circuits, AC and DC analysis, time domain and frequency domain analysis of analog circuits, etc. The circuit-level simulation must have the support of the component model library containing PSPICE parameters, and the simulation signal and output data replace the signal source and oscilloscope in the actual circuit debugging. Circuit simulation is mainly to test the correctness of the design scheme in terms of function. Circuit simulation technology makes it possible for engineers to fully understand the various characteristics of circuits before the actual electronic system is produced. Now circuit simulation is also widely used in the teaching of electronics in various schools.There are many types of commercialized circuit simulation software, with different software performance characteristics and application convenience. Choosing the appropriate circuit simulation software according to the needs of engineering and teaching can greatly improve work efficiency and teaching effect.1. Functional characteristics of circuit simulation technologyCircuit simulation has been widely practiced and proved to be a very effective analysis technique, which is adopted by more and more electronic designers. Circuit simulation technology can play a role in the following aspects.1. Verify the electronic circuit designUse circuit simulation technology to quickly simulate and analyze different circuit design schemes to ensure that the design ideas are correct. After the circuit form is determined, sensitivity analysis and tolerance analysis are performed on the circuit component parameters to optimize the circuit parameters and ensure the design quality. Circuit design adopts simulation technology, which can greatly reduce manual labor, shorten design cycle and reduce design cost. For example, there are a large number of complex analyzes in filter design. It will take a lot of time to manually calculate all the data. Using circuit simulation software, results can be obtained within minutes, and the error can be kept within the scope of engineering specifications.Compared with the traditional circuit measurement method, computer simulation can predict the change process and final result of a specific circuit parameter, so that people can have a deep understanding of the change law of circuit performance. For example, how much impact will the error of component parameters have on product performance? Which component error will have the greatest impact on circuit performance? Using Monte Carlo analysis in circuit simulation technology can quickly draw conclusions. Using worst-case analysis, designers can easily test various extreme conditions and observe the response of the circuit under extreme conditions. Sensitivity analysis enables users to determine the proportion of change in circuit performance parameters such as period, gain, or rise time due to design or component parameter changes.Circuit simulation technology is especially advantageous in experimental studies where routine measurements are difficult, especially in destructive experiments in real systems. For example, some electronic designs involve high voltage and high current, incorrect design parameters may cause damage to electronic components and hinder the design process. Circuit simulation used in digital circuits also has the characteristics of high efficiency and high precision. Using simulation technology before building the circuit can avoid all kinds of fatal damage and increase the success rate.As a simulation technique, simulation cannot completely replace the actual measurement of real circuits. However, various parameters produced by simulation have decisive significance in design, and also provide a data basis for physical experiments.2. Auxiliary teaching for electronics majorsElectronics is a highly experimental subject. It is best to study the principles of electronics simultaneously with experiments to deepen perceptual knowledge. Experiments require measuring instruments and electronic components. When limited by objective conditions, it is an effective method to verify the conclusion of theoretical analysis with circuit simulation. Circuit simulation can record all the data in the analysis, and can easily reproduce various electrical processes, especially some fleeting phenomena. For example, the start-up process of an oscillating circuit is generally only about 1 millisecond. This process cannot be observed on an oscilloscope without a memory function. Using simulation can record the whole process of circuit start-up; for example, circuit simulation software can be used to build various operational circuits and verify the circuit theory of operational amplifiers at any time, which is easier and faster than building experimental circuits. The drawn circuit diagram and the generated simulation curve can be copied to the document, making your experiment report look more convincing.To study electronic circuits, one must not only master the basic principles and calculation methods, but also pay attention to the cultivation of circuit design, analysis and research and development capabilities. It is usually impossible for laboratories to provide the latest devices from various manufacturers in the world. The circuit simulation can be simulated and analyzed using the model of the new device. The application of circuit simulation technology can also design different forms of training such as verification, testing, design and innovation, so as to cultivate students' various abilities.3. Learn electronic engineering measurement technologyMeasurement is one of the fundamental skills in electronics. There are two requirements for electronic measurement: mastering the operation method of electronic instruments and data collection and analysis.In electronic measurement, a variety of signal generators are used: such as high-frequency signal generators, low-frequency signal generators, and function generators. The signals generated by these instruments can be realized in the circuit simulation software: for example, the transient source can generate various signals of the function generator, and the nonlinear controlled source can generate amplitude modulation waves, etc. By setting the signal parameters of the simulation source, the electrical meaning of various waveforms can be deeply understood.In the graphics interface of the simulation software, according to the expectation of the measurement results, the display parameters of the waveform are selected, which is equivalent to adjusting each knob of the electronic instrument. The waveform graph produced by circuit simulation has a larger format and more precise coordinates than the oscilloscope screen. The graph measurement tool of the software can perform various measurements on the signal curve, such as the amplitude, frequency, period, phase of the periodic signal and the rise time of the pulse signal, the overshoot amplitude of the signal, etc. The measurement tool is fully graphical, highly interactive, and can automatically calculate various parameters.Waveform calculators perform mathematical calculations on waveforms. The waveform calculator uses various mathematical symbols and functions to calculate signal data such as average value, differential integral and so on. In most software, using the waveform calculator, complex function expressions can be constructed interactively to generate new waveforms. The measurement results of some simulation software can be marked directly in the chart.Using virtual instruments in some software (such as Multisim) is very helpful to master the performance and operation of real instruments.2. Basic performance of circuit simulation softwareWith the development of microcomputer technology, the level of EDA software based on Windows has been continuously improved. Now there are many different software companies producing circuit simulation products for PC. These products have different technical grades and application positioning. Some software with printed circuit board design as the main application also has embedded simulation components, such as ORCAD's PSPICE, Protel's Simulate, etc. There are many brands dedicated to circuit simulation products, such as Multisim, TINA, ICAP/4, Circuitmaker, and Micro-CAP. Usually these softwares are based on the circuit simulation language PSPICE.The interfaces and functions of various circuit simulation software have their own characteristics, and the display and processing methods of data are also different. The practical value of circuit simulation software can be evaluated from the following four aspects.1. Quantity and performance of simulation projectsThe number of simulation items is the main index of circuit simulation software. The basic analysis functions of various circuit simulation software include static operating point analysis, transient analysis, DC sweep and AC small signal analysis. Other possible analysis functions include: Fourier analysis, parameter analysis, temperature analysis, Monte Carlo analysis, noise analysis, transfer function analysis, DC and AC sensitivity analysis, distortion analysis, pole and zero analysis, etc. Software with fewer simulation functions such as SIMextrix has only 6 items, while TINA has as many as 20 items. There are about 10 simulation functions of Protel, Orcad, P-CAD and other software. Professional circuit simulation software has more simulation functions, and considers the various needs of electronic design and teaching more thoughtfully. For example, the symbolic analysis of TINA, the component parameter variable and optimization analysis of Pspice and ICAP/4, the network analysis and digital circuit simulation of Multisim, and the error setting of CircuitMaker are all quite distinctive functions.The PSPICE language is good at analyzing analog circuits, and the processing of digital circuits is not ideal. Various software solutions are not the same: For example, Protel uses Digital SimCode to describe digital components, and uses XSPICE of Georgia University to process digital simulation. Multisim uses collaborative models of analog and digital devices described in VHDL, Verilog, or C code. For the analysis and simulation of pure digital circuits, it is best to use simulation software based on hardware description languages such as VHDL, such as Altera's programmable logic device development software MAX+plus II.2. Quantity and accuracy of simulation componentsThe quantity and precision of the simulation components in the software component library determine the applicability and accuracy of the simulation. The component library of circuit simulation software has thousands to 10,000 or 20,000 simulation components, but the component models contained in the software always lag behind the development and application of devices. Therefore, in addition to the component library of the software itself, the website of the component manufacturer is an important source of component models. Designers can customize component models according to the external parameters of the latest devices and build their own component libraries. For teaching workers, the component model library of the software can fully meet the needs of conventional teaching.There are two ways to classify components in circuit simulation software: by component types such as power supplies, diodes, and 74 series, into several categories; or by component manufacturers. Most simulation software has previews of circuit graphic symbols for easy access. Each circuit simulation software has simplified the PSPICE model of the components. For example, the resistance model of PSPICE has three temperature coefficients such as first-order, second-order and exponential. Most software only defines the first two temperature parameters, only TINA defines the three temperature parameters of the resistance, and the resistance of Protel does not define the temperature coefficient; for example, the bipolar transistor has 40 PSPICE model parameters, and Multisim specifies all the parameters , TINA also has 32, and Protel has only 22. Therefore, designs that require high simulation accuracy should use high-precision component models, or modify model parameters based on actual components. The method of viewing and modifying component models varies from software to software. Some component model parameters can be modified in the component attribute box, while others need to open a special model parameter file or interface to modify.3. Data display and processing capabilitiesAfter running the simulation, a large amount of circuit data will be obtained. There are two ways to display simulation data: list and graph. For example, after calculating the DC static operating point, Protel displays the node voltage, branch current, component consumption function and equivalent resistance of the power supply in a list; Pspice and MicroCAP can mark the voltage, current and power in the circuit diagram. Transient analysis, DC sweep, and AC small-signal analysis generally display the results as graphs. The graph can be printed or saved as a file in a specific format; some software can save the waveform as a common PWL (expressed in time-electrical quantity pair) format file, or export it to Excel. You can also copy the graph line, paste it into the "Drawing" of Windows, and save it as a picture file after processing; or directly paste the graph line into the document of Word, PowerPoint, Authorware and other software.Each circuit simulation software has different processing capabilities for waveform graph lines. But generally there are the following data processing functions:(1) Waveform measurement: displayed as different types of coordinate scales (linear, logarithmic, amplitude, decibel, etc.); measure the effective value, root mean square value, peak-to-peak value, average value, maximum value, minimum value, cycle, etc. of the graph .(2) Graph line calculation: Add, subtract, multiply, divide, differentiate, integrate and other operations on the graph line. Or use the graph variable as the independent variable of the mathematical function to obtain a new mathematical variable.(3) Modification of graph lines: Make graph lines more beautiful and easier to understand. You can change the thickness, color, style and mark of the graph line; add measurement data point marks and data labels; change the background color of the graph line, the style and color of the coordinates, etc. Some software allows the input of descriptive text in the graph line screen, even Chinese text.4. Virtual instrument and educational functionVisualized virtual instruments are a feature of circuit simulation software. The most typical example is Multisim, the virtual instrument of this software has reached the highest level of similar software no matter the appearance of the interface or the internal function. Other software with virtual instruments include TINA and EDISON.Virtual instruments can help learners understand the functions of electronic instruments, and deeply understand the methods and technical essentials of electronic measurement. Master various operation methods of electronic instruments, especially the functions of various control buttons and knobs. The functions of Multisim and TINA virtual instruments have actually surpassed PSPICE itself, and the typical ones are network analyzers and logic analyzers. Network analyzer is a special instrument for analyzing RF components and RF network parameters; while Multisim's logic analyzer has real digital circuit analysis capabilities and meets the technical requirements of actual digital system analysis. Some software also has virtual electromechanical components, such as light bulbs, buttons, relays, contactors and other electrical components, which can be used to construct electromechanical control circuits. Mathematical and analog control devices in the software component library can be used to analyze automatic control principles.In order to meet the needs of educational units for the teaching of circuit principles, some software has an educational function. It mainly allows users to set some hidden errors on components, so as to improve the ability of training students to analyze and solve problems. For example, Mulisim and TINA can set three parameters of open circuit, short circuit and leakage resistance for components; while CircuitMaker, another circuit simulation product of Altium Company, can do more teaching settings for components and circuits, and can add passwords to prevent users from Modify component properties.3. How to choose circuit simulation software?In the production design of electronic engineering or the professional teaching of electronics, there may be different requirements for circuit simulation software, which should be considered from two aspects: software function characteristics and actual work needs.1. Consider the needs of production and teaching for circuit simulation software.First of all, the actual production capacity of the software must be considered. What kind of work can be done with this software? Can the model library of the software meet the design needs; what circuit simulation functions does the software have; what output formats the circuit diagram has, whether it is compatible with the company's existing PCB design software; the price of the software and what after-sales services are provided, etc. If the unit's products are more complicated, it is necessary to consider a comprehensive solution from circuit design, analysis, optimization, system simulation, and even electromechanical system design.2. Evaluate the performance of circuit simulation softwareThe software products of various companies have different sales orientations, and the functions, scalability and prices of circuit simulation software vary greatly.There are different versions of the same software to suit different business needs with different functions and prices. Ordinary teaching units only need to learn the relevant principles of circuit simulation, and do not have to insist on high performance of the software. Using the student version or educational version of the software can fully meet the needs of daily teaching. As an electronic manufacturer, it is necessary to use the enterprise version or enhanced version of the software, and also consider a series of issues such as product design, production and management, and also have certain requirements for software maintenance and technical support. Therefore, products from large companies should be used as much as possible. Such as ICAP/4, Orcad, etc.; if you have higher comprehensive requirements for circuit design and simulation, you can consider Saber from American Synopsys. Saber is applicable to a wide range of fields, including electronics, power electronics, electrical engineering, mechanical engineering, electro-optics, optics, control systems, and data sampling systems, etc.3. Select the applicable software according to the teaching needsIn teaching, circuit simulation software is required to clearly display circuit diagrams, signal diagrams and various circuit data. Among all circuit simulation software, Multisim has the most complete simulation components, simulation analysis types and virtual instruments, and is an ideal simulation tool for circuit teaching in schools at all levels. The disadvantage of Multisim is that the circuit diagram screen can only be enlarged to 200%, and the circuit lines are relatively thin, which is not very clear when projected on a large screen. The circuit simulation software that is more suitable for vocational technical schools is TINA 6.0 Simplified Chinese version. Not only the menus and dialog boxes of this software are in Simplified Chinese, but all the help is also written in Chinese, which is easier for students to understand and accept. The display quality of Altium's circuit diagram and simulation diagram interface is relatively good, which is suitable for teachers to use in teaching slide presentations and making illustrations in various documents. Altium is also well suited for teaching printed circuit board design. The advantage of ICAP/4 is that the simulated circuit waveform can be inserted into the circuit diagram, that is, the waveform at any point in the circuit can be displayed. Orcad's Pspice displays the simulated node voltage, branch current, and component power consumption data in the circuit, which is very intuitive; MicroCAP has the most powerful parameter scanning function, and can set up to 20 parameters for scanning analysis. If you are a beginner in electronics, you can use the circuit simulation software Edison with a 3D interface. The software interface is vivid and intuitive, which is quite close to the real image, which is helpful for understanding and understanding the circuit.4. Dedicated circuit simulation softwareIn addition to the usual circuit simulation software, there are also some software specially designed for a certain type of design application, such as: Intusoft's power supply simulation design software PowerSupply Designer and magnetic components (design analysis transformers and inductors) design software MagneticsDesigner; Finland APLAC company The software APLAC for RF circuit design and simulation; and the series products of American Ansoft Company, etc. Many semiconductor device manufacturers have also developed special circuit design and simulation software in order to promote their products. Such as Altera's programmable logic device design software Max+PlusI I; TI's switching power supply special design software SWIFT Designer; Linear's circuit simulation and switching power supply design software SwicherCAD, etc.SummarizeFinally, it should be noted that the development direction of circuit simulation software is no longer limited to the scope of electronics. While enhancing the simulation ability of digital-analog mixed signals, circuit simulation technology is expanding to the fields of power electronics, electro-optics, and even electrical engineering, electromechanical engineering, etc., bringing more convenience to engineering practice and teaching. Circuit simulation technology has a powerful circuit analysis function, basically including all items of electronic test analysis. The number of electronic simulation components, circuit analysis functions and data processing capabilities provided by circuit simulation software from different manufacturers are quite different. The appropriate circuit simulation software should be selected according to the needs of engineering design and professional teaching.The above are the characteristics and selection suggestions of the circuit simulation software introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have software and hardware function development needs for smart electronic products, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad, including MCU, voice IC, Bluetooth IC and modules, wifi modules. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth wifi development, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS solutions, the development of Bluetooth audio, the development of children's toys, and the development of electronic education products.