Three-Level Gate Drive for Crosstalk Suppression of GaN Devices With Low Reverse Conduction Loss

The crosstalk problem in gallium nitride (GaN) based bridge configuration limits the high-switching speed and high-frequency applications of GaN devices at high-voltage levels. A three-level gate drive for crosstalk suppression with low reverse conduction loss during both dead times at turn-on and turn-off is proposed in this article. The capacitor-NMOS circuit provides a low-impedance Miller current path to reduce the positive and negative crosstalk voltage amplitudes. Through a delay pulse module, negative gate–source voltage is accurately applied to suppress the positive crosstalk voltage peak and the GaN device is turned off in gate–source zero voltage during the dead time to reduce the reverse conduction loss. The value of the negative gate–source voltage depends on the Zener diode, which is flexible and adjustable. The proposed method, which is easy to control at a low cost, requires no additional driver IC and control signals. At the condition of 400 and 200 V dc bus voltage, the double-pulse test based on GS66508B verifies the effectiveness of the proposed method for crosstalk suppression of GaN devices.