An efficient ripple-free LED driver with zero-voltage switching for street lighting applications

An efficient ripple-free light-emitting diode (LED) driver circuit is proposed with zero-voltage switching (ZVS) and dimming control. The proposed driver circuit utilizes a full-bridge configuration. The LED lamp current is the sum of two inductor currents which are out of phase. This makes the LED lamp current ripple free. Larger portion of lamp power is supplied by the dc voltage source connected in series with LED lamp. Small amount of power is processed by bridge circuit. Devices of the bridge circuit conduct only ripple current of the load inductor and a small current of an inductor which helps in ZVS. Hence, both conduction and switching losses are reduced. In addition, LED lamp current can be regulated at required operating current. The dimming feature is attained by on-off control method. This proposed configuration also helps in reducing components count. An experimental prototype of 87 W has been developed and tested at full load and different dimming levels. Experimental results validate simulation results.