Differential-mode Modeling of Common Mode Chokes for EMI filter in Switching Power Supply

This paper proposed a high frequency modeling method of common mode chokes for EMI filter in differential mode. The method consists of two parts: components modeling by impedance measurement and near field coupling effects analyzed by electromagnetic simulation calculation. Finally, the accuracy of model could be verified by the comparison between simulated and measured curves of S parameters. This modeling method could be used to predict and improve the filtration performance of EMI filter in switching power supply.