Study of a Fast Over-Current Protection Based on Bus Voltage Drop for Gallium Nitride Power Device

Abstract

Due to the low threshold voltage, gallium nitride (GaN) high electron mobility transistor (HEMT) is prone to mis-conduction. Meanwhile, compared with silicon (Si) insulated gate bipolar transistors (IGBT) and silicon carbide (SiC) metal- oxide- semiconductor field effect transistor(MOSFET) devices, GaN HEMT have a shorter short-circuit withstand time at highvoltages, only a few hundred nanoseconds, which leads to a serious challenge to overcurrent protection. Traditional inductor detection and desaturation overcurrent detection have a long execution time, which are no longer suitable for over-current protection of GaN. Therefore, this paper proposes a new fast over-current protection method, which is based on the bus voltage drop. Through simulation and experimental verification, the result proves that the proposed protection method can detect the over-current signal within 100ns and turn off the GaN device within 400 ns, achieving fast and reliable over-current protection.