Experimental Evaluation and Analysis of Switching Transient's Effect on Dynamic on-Resistance in GaN HEMTs

The dynamic ON-resistance in gallium nitride (GaN) devices is problematic as it can impair the converter's efficiency the increased conduction loss. In this paper, the hard-switching transient's effect on the dynamic ON-resistance is, for the first evaluated experimentally on a commercial high-voltage GaN electron mobility transistor. A new R dyn_ds,on measurement with fast sensing speed is designed, and an accurate measurement of R dyn_ds,on can be realized experimentally within 49.6 ns after the device's current reaches to the load current. double-pulse-test setup is designed to comprehensively evaluate switching transient's effect on R dyn_ds,on under different operating conditions. From the experimental results, it is found turn-ON and turn-OFF gate resistance have a significant on the dynamic ON-resistance whereas the cross-talk effect R dyn_ds,on is negligible. Specifically, at 400 V/25 A, more (28.2%) increase in R dyn_ds,on is observed when the external turn-ON (turn-OFF) gate resistance increases from 0 to 20 Ω. Detailed discussion and quantitative analysis are provided to the experimental results. In terms of the turn-ON process, concluded that the R dyn_ds,on variation is mainly caused different numbers of generated hot electrons. For the turn-OFF transient, it is confirmed the variation of drain current at different slew rate leads to the R dyn_ds,on difference.