Demonstration of MHz-Frequency Operation of a Monolithic Self-Synchronized Rectifier IC in Flyback DC/DC Converter

Synchronous rectification offers an effective solution to improve efficiency of low-output-voltage flyback converters. Conventional synchronous flyback topologies using the discrete synchronous rectifier face challenges in precise timing control on the secondary side at high switching frequency. In this paper, we demonstrate the MHz-frequency operation of a flyback DC-DC converter using a new monolithic self-synchronized rectifier (SSR). The SSR IC, acting solely on its own drain-source voltage instead of external control signals, considerably simplifies converter design, improves system efficiency, and enables MHz operating frequency. Analysis, modeling, and experimental results are presented.