Wide band modeling of integrated power passive structures: the series resonator

This paper presents a higher order frequency plane model for an integrated series resonant power conversion module. The cause for the occurrence of high frequency impedance peaks is identified as the parallel resonance between the winding inductance and its inter-winding capacitance. The inter-winding capacitance can be calculated from a transmission-line-based lumped model using Schwartz-Christoffel transformation. The simulation results using the proposed model correlate the small-signal test results very well. The proposed higher order impedance model will help to evaluate the high frequency behavior of an ISRM or to minimize the high frequency parasitics. It can also be easily implemented in the design-oriented algorithm to facilitate the design and optimization of an ISRM. The application of this model to more complicated structures as well as some practical design issues is also discussed.