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.