An Ultra-Fast Short Circuit Protection Solution for E-mode GaN HEMTs

The Enhancement-mode (E-mode) Gallium Nitride High-Electron Mobility Transistor (GaN HEMT) has proven excellent electrical performance in various applications. Meantime, multiple comprehensive studies on the short circuit behavior show that GaN HEMTs has much shorter short circuit withstand time compared to conventional silicon (Si) devices. In this paper, the GaN HEMT short circuit capability is first introduced. Based on the testing results, the voltage dip on the phase-leg dc voltage under short circuit condition is proposed to be the short circuit detection signal, and the corresponding detection circuit and ultra-fast short circuit protection method is depicted. Finally, experimental results prove that with the proposed protection method, soft turn-off can be initiated within 200 ns and the short circuit current can be terminated in 281 ns.