A Simple Two-Channel LED Driver With Automatic Precise Current Sharing

A simple rectifying circuit for an isolated two-channel LED driver without active current-sharing control is proposed. An alternating current source can be used to generate a two-channel LED driver with the proposed rectifying structure. With the proposed H-bridge rectifier and a block capacitor in series with the secondary side winding of the transformer, the currents in two LED strings are shared automatically even for different LED strings with different voltage drops. The operation principle of the rectifier is analyzed with a sinusoidal current source, and it is verified with a series-parallel resonant (
LLC
) dc/dc converter. This proposed rectifier can be applied to other converters featuring a high-frequency current source link.