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Elimination of Electrolytic Capacitor in LED Power Supplies by Two-Phase Driving Approach
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| Author(s) |
Chi Shing WONG, Yuk Ming LAI, Ka Hong LOO, Chi Kong TSE |
| Abstract |
A two-phase driving approach for light-emitting-diode (LED) applications is proposed in this paper. Inthe approach, two rectangular AC sources are employed so that the output current ripple can be signifi-cantly reduced. It leads to the elimination of electrolytic capacitor from the driver circuit. The approachis realised by a dual asymmetrical half-bridge converter with LEDs as the load. Considering the manda-tory lighting standard for an AC/DC LED driver, the half-bridges are preceded by a valley-fill circuit formeeting the input power factor (PF) and current harmonic distortion requirements. Unlike other existinginterleaved LED drivers that can only obtain low current ripples in certain operating points, the proposedapproach can maintain a constant output current at all times even under large duty cycle dynamics dueto the use of a valley-fill circuit. To validate the feasibility of the proposed approach, a 13 W prototypeis built and tested experimentally. |
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| Filename: | 0225-epe2014-full-11374934.pdf |
| Filesize: | 2.376 MB |
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| Type |
Members Only |
| Date |
Last modified 2015-06-08 by System |
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