Resonant Gate Drive for High Frequency Active-Bridge Power Converters

The paper presents the design of a resonant gate drive (RGD), which can be employed in various high-frequency power converters where active bridges operate at ~50% duty cycle. The RGD design is based on an LCLC resonant tank and a small gate-drive isolation transformer. The proposed RGD is simple to implement, does not require auxiliary supplies or high-side gate drivers, has low losses, and provides isolation and intrinsic dead time. A hardware prototype is set up to validate the functionality of RGD on a GaN-based full-bridge inverter, which drives a 500W, 6.78 MHz wireless power transfer (WPT) system. The complete system is tested up to a DC input voltage of 300V with a resistive load. The experimental results show that the dead time generated by the resonant gate driver is sufficient to achieve the ZVS of the power-stage inverter GaN-FETs at all operating points. It is also shown how the RGD reduces gate drive losses almost three times compared to the conventional gate driver.