Hybrid passive current sharing method for multi-channel SRC LED driver

In this paper, a precise cost-efficient hybrid passive current sharing method for multi-LED driver with series resonant converter (SRC) topology is proposed. By employing the balance capacitor and coupled inductor, the proposed multi-channel LED driver can achieve good current sharing among different LED channels. The resonant capacitor of SRC is used as balance capacitor to share two output currents in the same module. With coupled inductor blocking the different AC voltage caused by two modules, the current balancing of different modules can be guaranteed. The circuit presented has very simple structure due to only one power transformer is used. Compared with the conventional current balancing technique, the proposed methods can achieve high performance as well as low cost. An 80W prototype with 360V~400V DC input voltage and four balanced outputs is built to verify the proposed current sharing circuit.