Analytical Switching Loss Modelling based on Datasheet Parameters for MOSFETs in a Half-Bridge

Abstract

Modern wide-bandgap devices, such as SiC- or GaN-based devices, feature significantly reduced switching losses, and the question arises if soft-switching operating modes are still beneficial. For most of the semiconductor devices, only limited information is available to estimate the switching losses. Especially, if a wide operating range is desired, excessive measurements have to be performed to determine the switching losses for arbitrary operating points. Therefore, in this paper, a fast calculation method to determine the switching losses based on the charge equivalent approximation of the MOSFET capacitances, relying only on datasheet parameters, is presented. In addition, the turn-OFF losses at high switching currents are investigated, and an analytical expression to estimate the maximum current range for which the MOSFET can be turned off with negligible switching losses is proposed.