Electrolytic-capacitor-less high-power LED driver

Conventional topologies for high-power LED drivers with high power factors require large capacitances to mitigate the output current ripples. Electrolytic capacitors are commonly used because they are the only capacitors with sufficient energy density to accommodate high power applications. However, the short life span of electrolytic capacitors significantly reduces the life span of the entire LED lighting fixture, which is undesirable. This paper proposes a single-stage high-power LED driver using ripple compensation concept to minimize the output capacitance requirement, enabling the use of long-life film capacitors. Compared to existing technologies, the proposed circuit achieves zero ripple current through LED lamps and achieves a high power factor and high efficiency. A 100W (150V/0.7A) LED driver prototype was built which demonstrates that the proposed method can achieve the same LED current with only 44μF film capacitors, compared to the 4700μF electrolytic capacitors required in conventional single-stage LED drivers. Meanwhile, the proposed prototype has achieved a peak power efficiency of 92%, benefiting from active clamp technology.