High-efficiency quasi-two-stage converter with current sharing for multi-channel LED driver

In this paper, a novel active current sharing method for multi-LED driver based on quasi-two-stage converter is proposed. In the presented structure, the DC/DC converter that operates current-loop regulation only processes a small portion of the total power. By employing the partial power control, high efficiency and low cost can be achieved due to the low voltage stress, high switching frequency and smaller size of passive components. Compared with passive method to achieve current balancing among the multi-output LED strings, the active method is simpler to control and has better load adaptability. Performance of the proposed scheme is validated by the experimental results from an 80W prototype with four LED strings.