Capacitor clamped current sharing circuit for multistring LEDs

This paper proposes a simple capacitors clamped current sharing circuit for multi-string LEDs to solve the current imbalance problem caused by voltage drop tolerance and the negative temperature coefficient of LED, which employs staggered turn-on switches and multi-capacitor charge conservation. The operating principle and parameter design of the topologies are analyzed in detail. On this basis, three-string current sharing topology has been validated by experiments. Experimental waveforms show that the proposed circuit not does have good effect on current sharing while the effect isn't affected by the output voltage of each branch, but also has the advantages of low voltage stress, non-magnetic components, ease of integration and simple control.