Zero-voltage-switched quasi-resonant buck and flyback converters — Experimental results at 10 MHz1

Experimental results of buck and flyback zero-voltage-switched quasi-resonant converters (ZVS-QRCs) operating above 5 MHz are presented. A design procedure is presented that minimizes voltage stress to the transistor while maintaining zero-voltage-switching for all loads. A novel, quasi-resonant gate drive scheme is proposed and implemented in a buck converter. The drive is simple and provides high switching speed. Power dissipation in the gate drive is substantially reduced due to the quasi-resonant operation. Due to a much reduced switching losses, dv/dt, and di/dt, the ZVS-QRCs are particularly suitable for very-high-frequency distributed power supply applications.