A High-speed Dynamic Gate Driver with Low Oscillation for GaN HEMTs

GaN HEMTs are extremely sensitive to the parasitic inductance of driving loop due to the short switching time and the low maximum allowed gate voltage. However, for conventional gate driver, it’s impossible to achieve high switching speed and low voltage overshoot simultaneously. In this paper, a dynamic gate driver with suppressed gate voltage overshoot is proposed. The dynamic three-stage switching process realized by the high-speed and low-speed branches enables fast charging/discharging during the first stage and low oscillation during the last stage. Therefore, the proposed dynamic gate driver achieves short switching time of 9.76 ns and low voltage overshoot of 0.60 V at the same time, which are reduced by 8.36% and 34.78% compared with the conventional gate driver. The switching loss of the buck converter with the proposed dynamic gate driver is reduced by 18.5% and the drain voltage oscillation during dead time is much reduced.