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 V 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.