Abstract：This paper proposes a simple capacitor 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 switchs and multi-capacitor charge conservation. The operating principle and parameter design of the topology are analyzed in detail. On this basis, three-string current sharing topology validated by experiments and relative experimental waveforms are presented, which show that the proposed circuit has 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.
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2013, Vol. 28 
