Crosstalk Analysis and Suppression of GaN Driving Circuit in Bridge Converter

Abstract

Enhancement mode Gallium-Nitride power transistors (GaN HEMT) have emerged as promising devices for high frequency, high efficiency and high power density switch m ode power supplies. However, when GaN device works in high frequency, the dv/dt and di/dt slopes are increased due to stray inductances and parasitic capacitances, which leads to oscillations and overshoots in gate-source voltage and affect the stability of driving circuits. Especially in the phase-bridge circuit, the crosstalk between the upper and lower switch seriously limits the performance of the device. In order to solve the short circuit problem of bridge arms generated by oscillation and crosstalk, an improved design of gate driving circuit was proposed, which could eliminate the parasitic oscillation and voltage spikes, suppress crosstalk and higher harmonics effectively. In addition, A double pulse test prototype is built and the simulation and experimental results verify the effectiveness of this driving circuit.