Research On Planar Passive Integration For Emi Filter Of Switching Mode Power Supplies

Power electronic devices of Switching power supply is toward the development of modulation and miniaturization,and switching frequency of Switching power supply is higher and higher,while the discrete EMI filter is not only bulkly,but also the parasitic parameters of which and lead bring serious high-frequency problems.In order to meet the requirements of the Switching power supply,the paper presents a new type of planar passive integrated EMI filter.The paper analyzes the high-frequency problems caused by high-frequency parasitic parameters of discrete EMI filter.Then on the basis of the reseach results of home and broad ,the paper achieves the planar passive integrated EMI filter with PCB winding and integrated L-C structural winding unit,which achieves planar passive integration for common mode inductor,differential mode inductor and common capacitor.And the experimental prototype and verification are given.At last, the planar passive integrated EMI filter is verified through Maxwell electromagnetic field simulation software and Pspice circuit simulation software.The results show that the planar passive integrated EMI filter not only has small volume and height,but also has good performance,which provides technical support for switching power supply electrical power devices modularized.