A specific switching characterization method for evaluation of operating point and temperature impacts on wide bandgap devices

Abstract

Wide Bandgap Devices (WBD) are expected to be used in high efficiency, high frequency and high temperature power converters. In this paper, a special pulse mode buck converter characterization bench is presented. It allows to precisely evaluate the impact of the operating point and the temperature on the WBD switching performances with the least possible interferences and the maximum level of flexibility. An electro-thermal simulation shows that the thermal stress due to the device characterization is considerably reduced, compared to the classical double pulse method, therefore removing the need of a thermal conductive packaging for the DUT. Indeed the desired switching conditions are smoothly set in less than 3 ms by an auxiliary transistor before the WBD under test switches only one time. Finally a SiC JFET has been characterized on a wide range with a single inductor until 250V/20A and up to 150°C to study its switching characteristics dependency.