Lossless turn-off switching projection of lateral and vertical GaN power field-effect transistors

New physical insights into switching loss evaluation are applied to GaN power field-effect transistors, including p-AlGaN gate HEMTs, MOS channel HEMTs, and vertical UMOSFETs. Internal channel current is used to calculate true switching loss values for both turn-on and -off. In contrast to conventional terminal current-based loss calculations, energy stored in device output capacitances during turn-off and dissipated during turn-on is counted as turn-on loss rather than turn-off loss. At appropriate RG and off-state VG values, lossless turn-off can be achieved for MOS channel HEMTs and UMOSFETs, but not for p-AlGaN gate HEMTs. In appropriate circuit applications, near zero total switching loss can be realized by combining lossless turn-off and zero-voltage turn-on.