A High Frequency Dual-Channel Isolated Resonant Gate Driver For ZVS Full Bridge Converters

To increase the switching frequency of the power converters can help to reduce the size andvolume of the passive components, so that the power density can be increased. However, as theswitching frequency increases, the switching loss and gate drive loss increase proportionally. Softswitching technique is one of the effective solutions to reduce the switching loss at high switchingfrequency. However, the excessive gate drive loss may still exist and cause lower efficiency andreliability as the switching frequency increases. In the last twenty years, Resonant Gate Drivers (RGDs)have been proposed with the objective of recovering gate energy loss in the conventional VoltageSource Drivers (VSDs). However, there was little work reported on the RGDs suitable for the FBconverters to reduce the excessive gate drive loss with the ZVS technique at high switching frequency.A dual-channel isolated Resonant Gate Driver (RGD) is proposed in this paper, which is suitablefor the widely used Full-Bridge (FB) converters. The proposed RGD is able to provide two isolatedcomplementary drive signals for a pair of power MOSFETs in one bridge leg. Furthermore, theproposed RGD reduces about79%gate drive loss compared to the conventional Voltage Source Driver(VSD). In addition, the negative gate drive voltage provided by the proposed RGD prevents the falsetrigger problem in the FB converters. The comparison to the conventional VSDs demonstrates thepower loss reduction achieved by the proposed RGD. The principle of operation and optimum designof the proposed RGD are given in detail.A200-VDC input,48-V/20-A output and500-kHz phase-shift ZVS FB converter with theproposed RGD was built to verify the advantages and efficiency improvement.