FEA tool approach for determination of parasitic capacitance of the windings in high frequency coupled inductors filters

Understanding and predicting parasitic winding capacitance in coupled inductor filters is essential to improve the high-frequency filtering performance. At high frequency, the behavior of coupled inductor filter differs from the low frequency and can be dominated by the parasitic inter- and intra-winding capacitances. This paper presents a finite element technique to analyze the high-frequency behavior of the coupled inductor filter in a buck converter. Comparison of the FEA results using JMAG with experimental and empirical formula results show good agreement, supporting the method as a model-based design tool with the potential to significantly reduce the design-prototype-test cycle commonly needed with sophisticated magnetic designs.