Flyback converter with novel active clamp control and secondary side post regulator for low standby power consumption under high-efficiency operation

Abstract

Flyback converters are widely used in industrial and commercial products because of their advantages of simple structure and low cost. Energy and environmental conservation have prompted interest in high efficiency and low standby power consumption in switch mode power supply applications. However, it is difficult to satisfy both conditions simultaneously because of conflicting design considerations. A novel active clamp control method is proposed for improving power conversion efficiency and reducing standby power consumption in a flyback converter. In addition, an asynchronous-type secondary side post regulator is applied to the converter for minimising standby energy leakage and improving cross-regulation performance for a multiple output channel flyback converter. Operational principles, control schemes, switch stresses and power consumptions are analysed using a converter small signal model and mathematical equations of converter waveforms. The superiority of the proposed converter is verified using experimental results on 110 W prototype.