Analysis and design of a multi-channel constant current LED driver based on DC current bus distributed power system structure

The colourful light emitting diode (LED) strings require the corresponding driver to achieve independent control of each output current in the applications of RGB mixed colour LED lighting, LED projection etc. For this purpose, a multi-channel constant current LED driver based on DC current bus distributed power system structure is proposed and analysed here, which is composed of a source converter and several load converters as needed. The source converter adopts the flyback converter to realise power factor correction, electrical isolation, and the load converter adopts the current-type buck converter to realise independent control of the corresponding output current. A 60 W experimental prototype for 42.8 V/0.35 A, 40 V/0.5 A, 35.7 V/0.7 A three outputs with the universal input voltages 90-264 V is designed and implemented, and the experimental results are presented to verify the correctness of the theory analysis.