多路LED串并联会引起电流不均衡，而电容充放电平衡以高均流精度被广泛采用。为得到所需LED驱动电流，常用的变频控制直接导致大的无功环流，提高了器件应力；且EMI电路复杂。而定频运行时，波动的负载软开关无法保障。基于此，论文提出一种基于可变电感(VI)的多路LED调光电路，不仅完成了恒频运行，缓解了EMI电路的复杂性，并且实现了开关管的ZVS，提高了能量转换效率。所提电路利用半桥结构叠加在增加均流路数的同时共用谐振电感，提高了系统的功率密度，简化了LED调光控制。本文详述了电路的工作原理，并以8路LED为例，搭建18W实验样机，验证了所提LED驱动电路的可行性。

The capactive charge balance scheme is widely adopted to eliminate current imbalance in driving multi-channel LEDs due to the high accuracy of current sharing. In order to get the required LED driving current, variable frequency control directly leads to large reactive circulation and increases the stress of devices, and the EMI circuit is complex. Soft switching can’t be guaranteed by constant frequency operation under load variations. Hence, a multiplex LED dimming circuit based on variable inductance (VI) is proposed in this paper, which completes the constant frequency operation, alleviates the complexity of EMI circuit, and realizes the ZVS to improve the energy conversion efficiency. The proposed circuit with superimposed half-bridge structure will increase the number of outputs and simultaneously share resonant inductor, so that the power density is improved and the LED dimming unit is simplified. This paper describes the working principle of the circuit, and takes 8-channel LEDs to build 18W experimental prototype for verifying the feasibility of the LED driver.