Analytical and experimental optimization of external gate resistance for safe rapid turn on of normally off GaN HFETs

This paper presents an analytical framework, supplemented with experimental validation, for optimizing the value of the external gate resistance employed in power conversion circuits using EPC enhancement-mode GaN transistors. A second order analytical model of the GaN device is utilized to determine a function that relates the external gate resistance to the peak gate voltage during turn-on. The results obtained from the analytical model were experimentally validated in a double pulse-test. The derived model allows for optimal selection of gate resistances such that GaN HFETs can be switched as rapidly as possible while keeping them in their safe operating region.