A single-stage quasi-resonant flyback converter using a synchronous rectifier

摘要: A single-stage quasi-resonant flyback converter using the synchronous rectifier (SR) is proposed for improving power factor and system efficiency. This operates at critical conduction mode with variable frequency (VF) control to reduce switching loss of primary switch. The bulk capacitor voltage can be independent output load kept within a practical range universal line input. Therefore, problem high-voltage stress across reduced. features relatively low in also complies Standard IEC 61000-3-2 Class D limits. Moreover, since it uses voltage-driven SR, achieves high operational principle theoretical analysis are presented. Experimental results 100 W (19 V/5.3 A) adapter VF were obtained show performance converter.