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.