Low Standby Power Consumption and High Cross Regulation of Active Clamp Flyback Converter with SSPR

Energy and environmental conservation have prompted interest in high efficiency and low standby power consumption in industrial switch mode power supply (SMPS) applications. However, it is difficult to satisfy both conditions simultaneously due to conflicting design considerations. In this paper, methods of low standby power consumption and high cross regulation are proposed using a novel active clamp control circuit and secondary side post regulator (SSPR) for a flyback converter with multiple output channels. The proposed active clamp control reduces the power consumption of the clamp circuit in standby mode, and the SSPR improves cross regulation performance and minimizes standby energy leakage. The superiority of the proposed converter is verified using theoretical analysis and experimental results on a 110W prototype converter.