White LED power supply based on Buck converter with active ripple compensation

Considering that the lifespan of electrolytic capacitors in power supply don´t match that of LED, we propose a Buck converter which uses active ripple compensation circuit to replace the traditional electrolytic capacitor filter. When the converter works on long duty ratio, the power loss in compensation circuit is small and ripple current and voltage are low. The operation principle of this new topology with peak current mode control (PCM) is discussed. The transfer function of PCM with slope compensation is established. The current loop stability with different slope compensation is discussed through frequency response analysis. Finally, simulation and experiment results of the power supply for LED verified correctness of the theory.