Abstract：This paper proposes a simple symmetrical crossing capacitors 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 topology are analyzed in detail and make a comparison with the unsymmetrical crossing capacitors current sharing circuit. On this basis, three-string current sharing topology was 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, and has the advantages of low voltage stress, non-magnetic components, ease of integration and simple control.
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2014, Vol. 29 
