A novel high efficiency and low-cost current balancing method for multi-LED driver

In this paper, a high efficiency and low-cost current balancing method for multi-LED driver is proposed. Based on the series resonant converter (SRC), the resonant capacitor can be used to balance the current between two LED outputs in one module. Moreover, with the help of the coupled inductors, the current balancing of all modules is achieved as well. The circuit presented has a very simple structure for the reason that a single power transformer is used. Though the amount of coupled inductors almost equals to the number of LED modules, not too many magnetic cores will be needed by using the technology of magnetic integrated. Thus, compared to the conventional current balancing technique, the proposed method can achieve high efficiency and very low cost as well as high performance. Performance of the proposed circuit is validated by the experimental results from a 80 W prototype with 360 V~400 V DC input voltage and four balanced outputs.