Analysis and design of CLL resonant multi-channel LED driver with balance capacitor

This paper presents a multi-channel light-emitting diode (LED) driver with CLL resonant converter. A CLL resonant converter is used in the primary side of the transformer to drive LEDs. On the secondary side of the transformer, current balance is realized with the balance capacitors, based on the charge balance principle. No additional magnetic components are used. With CLL resonant converter, zero voltage switching (ZVS) turning-on of the switches on the primary side and zero current switching (ZCS) turning-off of the diodes on the secondary side are simultaneously achieved. The voltage and current characteristics of the CLL resonant converter with balance capacitors are analyzed. Parameters of the elements in the circuit are designed. A prototype of 168W four-channel LED driver is built up. The experiment results prove that each LED has good performance of current balancing.