Efficiency Improvement Method of Flyback Switching Power Supply Based on Quasi-Resonance

Abstract

Flyback switching power supply is widely used in small to medium power scenarios, such as household appliances. The conversion efficiency is one of the key parameters for evaluating the power characteristics. The switch loss is an important factor affecting the conversion efficiency. Based on quasi resonant technology, ZVS (Zero Voltage Switching) or ZCS (Zero Current Switching) is realized in flyback switching power supply, which can effectively reduce the switch loss and improve the conversion efficiency. The sample test shows that the design in the paper can achieve ZVS through quasi resonance in all kinds of scenarios, effectively improve the conversion efficiency to more than 85%, and the no-load stand-by power consumption is less than 30 mW. The output voltage regulation rate is less than 2%. Moreover, multiple protection functions are included in the design. It is demonstrated that the design indexes are better than the similar products, and meet level VI energy efficiency standard, which has a wide application prospects.