Gate driver for safe operation of depletion mode SiC JFETs

Depletion mode silicon carbide junction field effect transistors provide the most promising perspective considering their on-state and switching characteristics as well as their robustness in future high-temperature applications. A major obstacle for an application in voltage source converters arises from the depletion mode characteristics of these devices. Therefore, additional efforts for the development of a safe gate drive system and startup strategies are necessary to ensure a safe operation. This paper deals with the development and design of a gate driver for depletion mode silicon carbide junction field effect transistors with redundant power supply and extended safety functionality, like undervoltage and short circuit detection. Printed circuit board integrated transformers with optimized winding layout have been designed to ensure low common mode coupling capacitance to exploit the high switching speed of the devices. The proposed gate driver is composed of commercially available components and integrated circuits suitable for ambient temperatures of up to 125°C.