High efficiency quasi-two-stage converter with current balancing for multi-channel LED drive based on AC bus

In this paper, a novel hybrid current balancing method for multi-channel LED drive based on quasi-two-stage converter is proposed. In presented structure, each output modules includes two LED strings and can achieve internal current balancing easily through its current balancing capacitor. The current regulators are used to balance the currents among the output modules. By applying the partial power control, the current regulator can obtain higher efficiency and lower cost due to higher switching frequency. Furthermore, by adopting the active method, the device has better load adaptability and lower voltage stress. Additionally, hybrid structure utilizes the advantages of passive and active method with simpler control. Performance of the proposed scheme is validated by the simulation and experimental results from a 120W prototype with four LED strings.