利用多地层结构改善集成EMI滤波器高频性能.docVIP

 利用多地层结构改善集成 EMI 滤波器高频 性能# 邓良勇，黄惠芬** 5 10 15 20 25 30 35 （华南理工大学电子与信息学院，广州 510641） 摘要：本文提出利用多地层平面绕组结构，地层绕组与共模绕组实现共模电容。一方面该结 构可以等效为两级 L-型低通滤波器，增加了对共模高频噪声的衰减；另一方面其等效电路 中每级电容的寄生串联电感相对单地层绕组结构有所减小，从而使由寄生串联电感引起的谐 振频率往高频移动，从而提高了高频性能。利用上述多地层平面绕组结构设计的集成 EMI 滤波器，与改进前的集成 EMI 滤波器比较，滤波器的插入损耗由电容寄生串联电感引起的 寄生谐振峰值被大大地减小，在 30MHz 时，插入损耗增加了约 25dB，滤波器的高频性能得 到了较好的改善。另外，文中还给出了改进后平面共模集成 EMI 滤波器的等效电路。在与改 进前的制作本成及复杂程度基本保持不变的情况下，实验结果表明该结构对改善平面集成 EMI 滤波器高频性能的有效性。 关键词：多地层；高频性能；平面集成 EMI 滤波器；等效串联电感 中图分类号：TN713 Improving the High-frequency Performance of Planar Integrated EMI Filter with Multiple Ground Layers DENG Liangyong1, HUANG Huifen2 (1. School of Electronic and Information Engineering, South China University of Technology, Guangzhou, 510641; 2. School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510641) Abstract: In this paper, a novel integrated winding arrangement is proposed, multiple ground winding layers are introduced to couple with common-mode (CM) choke windings to implement the CM capacitors. On one hand, the structure is equivalent to a two-stage L-type lowpass filter, which can largely increase the high-frequency attenuation. On the other hand, the ESL in every- stage equivalent circuit is also decreased so that the resonance frequency is shifted to higher frequency. An integrated EMI filter is designd with the novel winding structure, and the second resonance peak of transmission gain brought by the equivalent series inductance (ESL) is sharply decreased compared to the original structure to improve the high-frequency performance. At 30MHz, the insertion loss is increased by about 45dB. In order to better analyze the proposed structure, the equivalent circuit of the proposed integrated EMI filter is derived. Experiments indicate that the manufacturing cost and complexity is the same as the original integrated EMI filter, and confirm the filtering effectiveness of the proposed integrated EMI filter. Key words: multiple ground l