A novel self-oscillating synchronously-rectified DC-DC converter

A self-oscillating synchronously rectified DC-DC converter (SOSYRC) is proposed and examined analytically and experimentally. The converter is composed of an autonomous high-frequency push-pull oscillator, a synchronous pulsewidth modulated (PWM) controller/driver, a synchronous rectifier, and an output filter. The synchronous controller is built around a conventional PWM controller. Its function is to maintain zero voltage switching (ZVS) and to pass integer number of cycles of the main frequency to prevent saturation of the push-pull transformer due to unbalanced operation. The main features of the SOSYRC are: operation under ZVS conditions, sinusoidal voltage waveforms, and the ability to independently control multiple outputs. Another important feature is the fact that only a fraction of the resonant current passes through the switches. Simulation and experimental results were found to be in good agreement with the model developed for the proposed SOSYRC