The effect of gate drive topology on online silicon carbide MOSFET junction temperature sensing

The switching transient properties of conventional power semiconductors (Silicon MOSFET and IGBT) have been proposed for online junction temperature (T j ) sensing. This method utilizes the semiconductor T j dependent characteristics and the gate drive output dynamics. In this paper, the method is applied to wide bandgap power semiconductor, Silicon-Carbide (SiC) MOSFET. In order to demonstrate the SiC MOSFET T j sensing, de-capsulated SiC MOSFETs are implemented in an H-bridge. The SiC MOSFETs are driven by voltage source-based gate drive (VSG) and current source-based gate drive (CSG). The effect of using different gate drive topologies for this T j sensing method is compared based on different “gate drive — semiconductor” switching dynamic models. The “gate drive — semiconductor” dynamic model includes gate drive output stage, gate drive parasitics, SiC MOSFET intrinsic parameters, PCB parasitics, and a resistive load. Experimental results are compared with circuit LTSpice model simulation.