Improved De-Saturation Protection Circuits for Silicon Carbide MOSFET Gate Drivers

Abstract

High-performance desaturation or overcurrent protection circuit of the gate-drivers for Silicon Carbide (SiC) MOSFETs are essential for reliable and robust operation of advanced power electronics converters. The overcurrent protection circuits of the current state-of-the-art gate drivers have limitations with slow response speed and incapability to achieve robust operation under wide temperature variation and converter switching noises. In this work, improved desaturation protection circuits are introduced to overcome such limitations of the SiC MOSFET gate drivers. The proposed desaturation protection can operate at a significantly higher speed while also achieve higher noise immunity and robust operation across a wide thermal range. Analysis and design methods of the proposed circuit are presented towards the development of the improved SiC MOSFET gate driver. A comparison between the base-line gate driver circuit and the proposed gate driver circuit is carried out to show the improvements. Furthermore, the calculation for tuning the circuit components parameters to achieve appropriate overcurrent protection margin under a range of device junction temperature is presented. Detailed simulation and experimental results under short circuit test conditions are presented for verifying the proposed concepts and design of the improved desaturation protection for the SiC MOSFET gate drivers.