Dynamic On-Resistance Characterization of GaN Power HEMTs Under Forward/Reverse Conduction Using Multigroup Double Pulse Test

In bridgeless power factor correction converters and inverters, GaN high-electron-mobility transistors (HEMTs) operate in both forward and reverse conduction modes, which may feature different dynamic on-resistance (R-ON) behaviors. Despite the extensive study of dynamic R-ON under forward conduction, dynamic R-ON under reverse conduction still demands comprehensive evaluation. In this letter, the dynamic R-ON of two commercial p-GaN gate HEMTs with different technologies under forward/reverse conduction and hard/soft switching is characterized using the custom-designed multigroup double pulse test system, which nearly eliminates the accumulated self-heating effect in the device. First, the test was conducted at off-state bias voltage = 400 V, I-DS = 70% I-DS(max). For the Schottky-type p-GaN gate HEMTs, the dynamic R-ON in reverse conduction is found to be more than 3%-5% higher compared to the forward conduction. However, for the hybrid-drain-embedded gate injection transistor, operating in reverse conduction mode leads to a slighter dynamic R-ON degradation effect, with a reduction of approximately 10% compared to the forward conduction. Next, I-DS was modulated to evaluate its impact on dynamic R-ON. For both devices, during reverse conduction it was observed that the dynamic R-ON initially decreases and subsequently increases with the I-DS increase.