A 150V monolithic synchronous gate driver with built-in ZVS detection for half-bridge converters

This paper presents a fully-integrated high-voltage (HV) synchronous gate driver for driving power switches in zero-voltage switching (ZVS) converters. The proposed gate driver monitors the drain-source voltage of both high-side and low-side power FETs and determines proper dead time to turn on the FETs under ZVS conditions. Compared with traditional off-chip ZVS detection scheme which typically requires an additional transformer winding, the proposed design incorporates ZVS detector into the monolithic gate driver to minimize the volume of magnetics and other external components, and reduce the detection delay from more than 60ns to 15ns. Implemented in a 0.7pm HV BCD process, the proposed 150V synchronous gate driver enables 2MHz ZVS operations in a 60W two-phase half-bridge converter with eGaN power FETs and offers at least 840mW saving in the full-load conditions compared with the traditional off-chip ZVS detection scheme.