False Turn-on Failure and Protection of p-gate GaN HEMT in MHz Class-E Resonant Inverter

Featuring simple structure and natural soft-switching, the single-switch resonant power inverters usually operate at several MHz frequency. However, gate-node voltage rings caused by parasitic inductors challenge the device security and limit the operating voltage. To address this problem, this paper investigates the mechanism and protection of the false turn-on (FTN) problem as the p-gate gallium nitride (GaN) HEMT turning off. After FTN, the gate-control capability losses and source-node shows large leakage. Two important causes of gate-node voltage ring are high dv/dt noise on drain-node, resonance between device junction capacitors and parasitic inductors. Through circuit modelling, parameter design and experimental verification, reducing the Miller current amplitude in the gate-to-drain capacitor (CGD) can suppress the gate-node voltage ring, by using external small passive LC network.