An Energy Conservation Based High-efficiency Dimmable Multi-channel LED Driver

This paper presents a high-efficiency multi-channel LED backlighting driver with local dimming capability. A sequential burst-mode channel multiplexed pulse width modulation dimming scheme is introduced to regulate and maintain uniform LED current. An energy conservation technique is utilized to handle load disconnect situation, which significantly improves the efficiency over the entire dimming range. The proposed approach eliminates the dedicated linear current regulator and sensing components in each LED channel as required by recently reported methods. This work is well suited for digital IC implementation for dynamic LED luminance adjustment. The performance of the proposed method was verified experimentally using a 4.5 to 14V boost converter. An overall efficiency of 50-90% was observed over a wide range of LED luminance.