Single Power-Conversion LED Backlight Driving System With High Power Factor Control

A single power-conversion LED backlight driving system with high power factor control is proposed. The proposed converter is composed of a full-bridge diode rectifier and a quasi-resonant flyback converter. The proposed converter provides a simple structure, a low cost, and high power factor of 0.988 by using the novel control algorithm without the PFC circuit. To achieve good controllability, the novel control algorithm is transformed by adding a nominal value predetermined to relax its control burden. Detailed analysis and experimental results for a 90-W prototype are discussed.