A novel current sharing method without the signal line for multi-output LED driver

Current imbalance should be avoided when LEDs are applied in parallel. Conventional current sharing methods usually need a amount of the signal lines for each LED string which makes it difficult to design the PCB and modularize the LED driver. This paper puts forward a novel current sharing method and its working principle is analyzed in this paper which doesn´t need any signal line from each LED string. Through this digital control method, the output voltage can be adjusted to tightly follow the largest one among all the voltages across each LED string. Finally the performance of the proposed scheme is experimentally verified by a 180-W prototype with a load of five LED strings with linear-current-regulator.