Zener Diode Controlled GaN FET Gate Drive Protection Scheme

Innovation in GaN semiconductors has improved aspect of power capability, switching speed and size. However, their short-circuit withstand time is low compared to SiC and IGBT switches. It would require a response time of less than $400 \ \eta \mathrm{s}$ to reduce short-circuit damage to the device. This paper explores a quick turn-off gate drive circuit by implementing a zener diode control for the $V_{g s}$ of the GaN transistor. An additional soft turn-off subcircuit is added to discharge the gate capacitance in a short-circuit or load change event. Circuit operation is described in detail and simulation plots verify the hypothesis. Comparison for response time between different circuit topologies is also illustrated. Index Terms-Zener diode, Short-circuit fault protection, GaN-FETs, Gate driver, short-circuit withstand time, response time.