A Novel Crosstalk Suppression Method With Miller Clamp Circuit for GaN HEMTs

Abstract

Gallium nitride (GaN) power devices exhibit noteworthy characteristics, such as high switching speeds and low conduction losses, thereby facilitating enhanced efficiency and power density in switching power converters. Nevertheless, the advantages of high switching speeds and low conduction thresholds in GaN power devices also render them susceptible to bridge-leg crosstalk. To resolve the above issue, a novel miller clamp gate driver (NMCGD) is proposed. The detailed working principles of NMCGD are first elucidated in this article. In NMCGD, it utilizes the negative voltage to make the bipolar junction transistor (BJT) in a saturated state during the shutdown process of GaN. This action effectively short-circuits a portion of the drive resistor, reducing the impedance of the drive loop and suppressing crosstalk, which also reduces gate turn- on oscillation while ensuring prompt turn- on and turn- off speeds. At the same time, the parameter design and device selection criteria are presented. Notably, this NMCGD employs a minimal number of passive components, making it suitable for integration into driver IC. Finally, the efficacy of NMCGD is validated through a double-pulse test utilizing the INN650D150A GaN HEMTs.