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

Abstract

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. 2 Independent closed-loop control strategy The control schematic diagram of the proposed LED driver is shown in Fig. 2. Four current control circuits (CCS) are included to produce the drive signals of Q s , Q 1 , Q 2 and Q 3 , and eventually

Linear current module adaptive to wide operating voltage range based on automatic series/parallel conversion

“…The adaptive conversion of connection of current branches and load branches is controlled by a switch array. LED driver is one of the main applications of constant current source [23,24,26,27,28,29,30,31]. Based on the proposed linear current module, a four-segment LED driver is designed and experimentally verified.…”