The EMC Design And Optimization For Notebook Computer

Electromagnetic compatibility is a vital part of the electronic products design.Pursuing an harmonious electromagnetic environment is the purpose of EMC,and to ensure that the equipment or system can work well and without disturbing other equipment or system under the same electromagnetic environment.With the development of science and technology,electronic equipment has been integrate and functional diversification.The working frequency of circuit is getting more higher than before,the electromagnetic interference between the electronic equipment and its internal become more and more serious.The electromagnetic interference is the problem which can't be ignored.The notebook computer has been used as a research object in this article.This article describes the EMC design of electronic products and the key test items of international standards--EN55022 and IEC61000 for EMC Tests of information technology equipment.PCB layout is the most important part of the notebook computer EMC design.At this stage,good EMC design can reduce the EMI which comes from source.Combining shielding and grounding designs can make the product more stable.This article introduces the key points of EMC design during PCB layout.For example,it describes the requirements and EMC design for USB?LVDS?HDMI?VGA?RJ45?Audio signal and so on.The design of the mechanism mainly introduces the shielding and grounding materials and the design essentials of the notebook computer.After design,the notebook computer has tests in the third party laboratory,and tests include radiated emission test,conducted emission test and ESD test,and make rectification for charging circuit in PCB which has over the RE test limit in the test.It is discussed in detail how to determine the source of the problem from the near and far field,the causes which over the radiation limit of the standard are analyzed from the principle,and reduce the interference of the ground loop by changing the grounding mode of some components in the charging circuit,and make the rectification and optimization by reworking on the PCB,and ensure that it can meet international standards.Then revised the PCB to ensure that the final test results can pass the international certification.The design shows that by introducing EMC product design method at the product design stage,the product develop process and time are reduced.In the mean time,the coat of test and EMC rectification are reduced.As a result,the cost of product development is saved.The introduction of the notebook computer EMC design describes the EMC design,analysis and implementation method of the system-level products by theoretically and practically.This article provides a reference for the EMC design of system-level products.