A Detailed Experimental Switching Transient Performance Comparison of Normally-off GaN HEMTs

GaN HEMTs offer a viable replacement for silicon counterparts due to their superior switching and conduction loss performances. Commercially available normally-off high-voltage (600 - 650V) GaN HEMTs can be broadly divided into (a) Cascode GaN, (b) e-GaN, and (c) GaN GIT. Due to differences in device characteristics and gate driving requirements, the switching dynamics of these GaN HEMTs can vary significantly. This paper focuses on experimental investigations comparing the switching behavior of these normally-off GaN HEMTs. High voltage GaN HEMTs (600 - 650V) with a current rating of about 30A are considered for comparison. Double pulse tests are conducted, and the switching transients are obtained for a wide range of operating conditions. The key switching transient-related parameters, such as switching losses, transition times, (di / dt), (dv / dt), etc., are also compared. The results offer valuable insights for the optimal selection of GaN HEMTs in various power electronics applications.