A novel bipolar series Ripple compensation method for single-stage high-power LED driver
It has been well documented that series compensation (SC) configuration can significantly reduce the total output capacitance of LED driver without sacrificing the power factor (PF), thus enabling the use of long-life film capacitors. Most importantly, SC provides the advantages over the parallel compensation (PC) methods in that it reduces the voltage stresses of the auxiliary stage components and thus can provide a higher efficiency, which is especially desirable for highpower LED drivers. However, with conventional series compensation, the auxiliary stage requires an auxiliary winding from the main stage. This increases the cost as well as the complexity of the circuit design. In this paper, a novel Full- Bridge Ripple Compensation Converter (FB RCC) using floating capacitor is proposed. By innovatively controlling the power flow of this auxiliary circuit, the auxiliary winding can be eliminated, thus making the input side of the auxiliary circuit floating and rendering a more cost effective and more flexible solution for both isolated and non-isolated LED driver applications. The new ripple compensation method retains the outstanding ripplecancellation ability and high efficiency of the original SC method, and has been demonstrated in a 100W, 150V-0.7A experimental prototype.