在多路LED均流方案中,基于电容电荷充放电平衡的均流方案具有简单、精确、成本低、可靠性高等优点.结合可控开关电容(SCC)技术和电容电荷充放电平衡技术提出一种多路LED驱动电路.详细分析SCC的工作周期、稳态工作模态以及简化等效电路,得到了SCC等效电容对LED驱动电流的调控曲线.最后搭建了一台四路输出、每路(180~350mA)可调光LED驱动样机,样机可以实现模块内两路LED、模块间四路LED的精确均流,同时模块间通过SCC调控可实现独立调光,具有良好的调控性能和可拓展性.%Among the current sharing schemes of multi-channel LEDs, the scheme based on charge and discharge balance of capacitor is simple, accurate, low cost and high reliability. In this paper, a novel multi-channel LED driver topology is proposed, combined the switch-controlled capacitor (SCC) with the charge and discharge balance of capacitors. The operating period of SCC, the working mode of the module and the simplified equivalent circuit are analyzed in detail. The control curves of LED drive current versus the equivalent capacitance are obtained. A four-channel LED driver prototype was built up with good current sharing performance and expansibility. The controllable range of drive current is from 180mA to 350mA per channel. The prototype can achieve accurate current sharing of two-channel LED within a module, accurate current sharing of four-channel LED within different modules, and the independent dimming of different modules.
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