A high temperature de-saturation protection and under voltage lock out circuit for SiC MOSFET

SiC devices have a great potential to work in high temperature (HT) environment. To protect SiC MOSFET in HT environment, this paper presents a de-saturation protection and under voltage lock out circuit using commercially available discrete transistors rated at 200°C. A discussion on integrated circuit (IC) solution and discrete circuit solution is presented to evaluate feasibility and benefit to design such a multifunctional circuit with discrete components. The prototype circuit is designed, built and tested in a thermal chamber of 180°C. To discuss the circuit operation principles in details, the circuit schematic is analyzed in functional blocks. To validate the circuit performance, experimental test is conducted at both room and high temperature conditions. No problem is found during accumulative 25 hours thermal chamber test at 180°C.