How to integrate electromagnetic compatibility (EMC) design into product development process

1. The industry faces challenges

　　How to make your products meet the requirements of electromagnetic compatibility (EMC) standards in the corresponding market, so as to obtain relevant certifications quickly and at low cost, and smoothly enter the target market? This is the problem and confusion that every R&D company that is going to internationalize will face. The product R&D departments of various enterprises are facing huge challenges.

According to our understanding of most electronics companies in the industry, the current status of companies in EMC design is: "three nos"-product engineers do not master EMC design methods, companies do not have product EMC design processes, and companies do not specifically specify the person responsible for EMC. Mainly manifested in:

　　Because most domestic R&D engineers have not received the comprehensive EMC training experience of the system, they have no relevant design experience of electromagnetic compatibility products! I don't know how to solve the EMC design problem of the product? So we often see that a considerable number of product engineers are rectifying products all day, but they often do nothing and have no ideas!

There is no set of EMC design process within the enterprise. The quality of EMC performance design depends entirely on the quality and experience of individual product developers, so that the products developed by the company do not guarantee the consistency of electromagnetic compatibility performance, and usually appear in a certain link. The problem caused that most of the products could not pass the test and certification smoothly in the later period, which affected the product's market progress. According to our preliminary survey, more than 90% of electronic companies across the country do not have a set of EMC design and verification processes.

　　The enterprise does not have a responsibility system responsible for EMC performance, and there is no full-time EMC design engineer. Because EMC involves all links of the entire product, the entire company has no clear responsible person, so there is not enough attention, and at the same time, it can not coordinate all parts of the entire product to be jointly responsible for the final EMC performance of the product! At present, there are few engineers with EMC design in the industry, and even fewer companies have full-time EMC design positions!

　　 2. The industry is facing problems

　　The design of a product mainly goes through the stages of overall specification scheme design, detailed design, schematic design, PCB design, product structure trial assembly, bottom pre-testing, and certification. At present, many companies in the industry have not considered EMC issues in the early design stage, and often carry out EMC bottom-testing after the product prototype comes out. If the test passes at this time, it is relatively lucky. But unfortunately, in most cases, the test cannot be passed. At this time, problems occur and rectification is required, and the product needs to be redesigned, which often requires large changes.

At this stage, there are many reasons for problems with electromagnetic compatibility. If it is because of shielding problems, it will often involve structural mold changes. If it is because of interface filtering problems, the product schematic will be changed, and at the same time, PCB redesign will be caused, possibly because of the system. For grounding problems, it will readjust and redesign the entire product system. There is a famous instrument company in Shenzhen. A product has been delayed for one year due to electromagnetic compatibility problems. At the same time, the research and development costs have increased by 500,000 yuan!

　　 This kind of testing and repairing method that finds problems through post-development research and then conducts product testing is more common in the industry, but it often leads to the failure of companies to obtain certification and go to market in time. Therefore, it is also the confusion faced by many companies’ R&D departments that are going to the international market. The root cause of this status quo is: EMC problems have not been solved in the early stage of product design!

　　 3. System Flow Method

Product engineers can master EMC design methods through short-term training and accumulation of experience, but for an enterprise, it is urgent to establish a set of standardized EMC design processes to integrate electromagnetic compatibility requirements into product design. Ensure that most of the company's products successfully pass the test and certification through this process. If the correct EMC design strategy can be introduced from the early stage of the design process, and the R&D engineer masters the correct EMC design method to solve the EMC problem from the product design source, it will reduce many unnecessary manpower and R&D costs and shorten the time to market.

Many experts in the industry regard product EMC design mainly from the technical point of view, such as shielding, filtering, grounding, PCB design, etc., but for an enterprise, these are some technical knowledge points, theoretical description, the key is how in our enterprise How to implement in the R&D process of the company, and how to combine electromagnetic compatibility knowledge with our product design to form a operable specification and CHECKLIST (check control list) for enterprise products? So how to integrate EMC design into the R&D design process, we have summarized a set of advanced processes based on the EMC design processes of famous companies at home and abroad, which we call: System Flow Method (System Flow Method), which is mainly in R&D Integrate EMC design concepts into the process, carry out EMC design control at all stages of product design, and consider possible EMC problems in the early stage of research and development; during the design process, mainly from the product circuit (schematic diagram, PCB design), structure and cable, Power modules, grounding and other aspects of the system consider EMC issues, and fully consider the possible EMC issues in the early stage, so as to ensure that the product samples can pass the test and certification at one time!

4. Introduction to System Process Method

The system flow method is to carry out design control from the process in the research and development stage of product design to ensure that the EMC design concept and design means are implemented accordingly at each stage. In addition, EMC design is considered from the system perspective of the product, not just a certain Only in this way can the final EMC performance of the product be guaranteed.

　　Each company should establish a set of EMC design control process. At the same time, the corresponding EMC design specifications and EMC design checklists are needed to support this process, to ensure that the product can be controlled in all stages of the R&D process.

　　The detailed contents of each stage of the system flow method are as follows:

　　Product overall plan design

　　In the overall scheme design stage, EMC design considerations are required for the overall specifications of the product, mainly related to the target market of product sales, as well as the requirements of standards and regulations that need to be met. At the same time, pay attention to the EMC standards and regulations of potential target markets. Based on the above requirements of the product EMC standards and regulations, the overall EMC design block diagram of the product is proposed, and the overall product EMC design plan is formulated in detail, such as how to design the system shielding, how to design the filter based on the entire power supply topology of the system, and how to consider the product grounding. Wait.

If a complex data communication product is positioned in the European and Japanese markets, it is clear that the product must pass the CE and VCCI certification when entering the above market, and the overall system shielding, power supply, and signal interface filtering scheme must be considered. Three aspects of grounding are considered from the overall product plan to meet the above target market certification requirements.

　　At this stage, the product R&D personnel put forward the overall EMC plan, and the quality or specialized EMC engineers will conduct check inspection based on the inspection list.

　　Detailed product design

In the detailed product design stage, the main hardware EMC design solutions are proposed, such as: power supply interface, signal interface, cable selection, interface structure design, connector selection, etc., detailed EMC design and selection requirements are proposed. Ensure follow-up implementation In the process, we can focus on these points.

　　 If we design a medical device product, we need to pay attention to the isolation of the internal digital circuit module and the analog circuit module. We need to consider the interference of the digital circuit on the analog circuit from the internal space, and pay attention to the internal cable interface filter processing.

　　 At this stage, the product hardware designer puts forward detailed EMC schemes according to the existing specifications, and the quality or special EMC engineers carry out the check inspection based on the inspection list.