Measurement of Effective Common-Source Parasitics During Switching Transients

Abstract

This paper presents a measurement method for the extraction of the effective common-source impedance of high-power SiC MOSFET modules under realistic switching conditions. Existing approaches are limited for high-power modules by excitation constraints, power requirements, and bandwidth limitations. The proposed method uses an extended double-pulse test as broadband excitation and extracts common-source inductance and resistance in the time domain by an integral evaluation. The method is validated on a discrete SiC MOSFET using a defined reference impedance and compared with established AC measurements. Finally, the method is applied to a state-of-the-art 3.3-kV SiC half-bridge module to demonstrate its applicability and to evaluate the dependence of the extracted effective parameters on the switching transient.