Series–Parallel Autoregulated Charge-Balancing Rectifier for Multioutput Light-Emitting Diode Driver

A series-parallel autoregulated rectifying circuit is proposed for a multioutput dc/dc light-emitting diode (LED) driver. The series-parallel autoregulated characteristics balance the charge in the secondary blocking capacitors automatically. Hence, with the proposed rectifier and secondary-side multiwinding transformer, a multioutput LED driver with precise current-sharing capability is achieved even for multiple LED strings with different voltages. The operating principle of the rectifier is analyzed with a sinusoidal current source and is verified with a four-output LLC dc/dc LED driver. This proposed rectifier can be applied to other converters featuring a high-frequency current source link at the primary side.