Analysis and design considerations of LLCC resonant Dc-Dc converter with precise current sharing for two-channel LED driver

In this paper, a LLCC resonant converter with automatic precise current-sharing is proposed for two-channel LED driver. With a resonant capacitor connected in series with the transformer secondary winding, the currents of the two channels are precisely shared even for different LED strings with different voltage drops. The circuit operation principle, DC gain deduction and design considerations are discussed. A prototype of 140W two-channel LED driver is built to verify the proposed current sharing circuit.