应用于平面EMI滤波器集成LC元件寄生电容的提取

Extraction of parasitic capacitance of integrated LC component for planar EMI filter

为有效预估和分析平面EMI滤波器的高频特性,必须考虑平面电感的寄生电容对滤波器高频性能的影响。本文分别建立了应用于平面EMI滤波器集成LC元件的2D和3D有限元静电场模型来计算各匝间的寄生电容,由此得到PCB导线组成的多匝平面绕组的集总参数模型,进一步得到平面绕组的等效并联电容。讨论了介电常数对匝间电容的影响,并分析了边缘效应对有限元模型计算结果的影响,将计算得到的等效并联电容应用于对应的集总等效电路中,通过计算结果与测量曲线的对比,说明了该计算方法的有效性,可用于指导平面电感和集成LC元件的设计。

Aiming at predicting and analyzing the high frequency performance of EMI filter efficiently,the effect of parasitic capacitance of planar inductor must be considered.In this paper,the 2D and 3D electrostatic FE model of the integrated LC component for planar EMI filter is firstly presented respectively,through calculating the parasitic capacitance among the windings,the lumped circuit model for N-turns planar winding consisted of PCB inductor is derived,then the equivalent parallel capacitor of planar winding could be given out.By analyzing the effects of per-mittivity and fringing effect on parasitic capacitance,the calculated result is to be verified by comparison with meas-urement.The method of extraction for parasitic capacitance can be used to design the planar winding and the inte-grated LC structure.