ZHAO Rongrong, ZHANG Junming

 

(College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China)

 

 

Abstract: Aiming at solving the problem of current imbalance, low efficiency and high cost of the multioutput LED driver, study on the passive and active current balancing method were carried out, a novel hybrid current balancing method for multichannel LED drive based on quasitwostage converter was proposed. In presented structure, each output modules included two LED strings and could achieve internal current balancing easily through its current balancing capacitor. The current regulators were used to balance the currents among the output modules. By applying the partial power control, the current regulator could obtain higher efficiency and lower cost due to higher switching frequency. Additionally, hybrid structure utilizes the advantages of passive and active methods with simpler control. A 120W prototype with four LED strings was developed. The experimental result indicate that the proposed scheme has a good performance and higher efficient.

 

Key words: multioutput LED driver; current balancing; hybrid; LLC; high efficienc