750 W High Efficiency and Soft-Switching Off-Line 12 V Converter

The paper presents an innovative off-line low profile converter design that delivers 750 W of power at 95%-96% efficiency for nominal input range, using variable frequency topology with high frequency zero voltage switching (ZVS) and zero current switching (ZCS) for primary switchers. Theoretical considerations and practical results are presented for high frequency and high voltage soft-switching. The goal of the design is to maintain a reasonable temperature rise of the multi-layer PCB board while delivering 750 W power in a reduced volume and low cost. The resulting product increases more than twice the power density compared to the standard two stages 400 V to 12 V power converters and outperforms other one stage solutions in a 125times70 mm² footprint with only a 18 mm profile.