Experimental Study of the Coss-Losses Occurring During ZVS Transitions – Emphasis on Low and High Voltage GaN-HEMTs

Abstract:
GaN-HEMTs offer completely new possibilities for the development of advanced power electronics. GaN devices enable, due to the lower parasitics, higher switching frequencies. However, high efficiency at high frequent operation requires ZVS. It is typically assumed that the ZVS transitions are lossless. However, at least in case of Si-SJ-MOSFET experiments show that sometimes losses occur during charging and discharging of the output capacitances. For this reason, this paper examines the losses occurring during ZVS by employing Sawyer Tower measurements of GaN devices. Losses are meas-ured depending on the amplitude of the Drain-Source voltage and frequency, finding that these are negligible.