High-power single-stage LED driver with bipolar ripple cancellation

摘要

Provided are circuits and methods for a power converter that converts AC input power into DC output power using a first output circuit that provides a first output comprising a DC voltage with a first AC voltage ripple and a second output circuit including a floating capacitor and one or more power switching device, and provides a second output comprising a second AC voltage ripple, wherein the first output and the second output are connected together in series, such that the first AC voltage ripple is substantially cancelled and substantially ripple-free DC output power is provided. Embodiments significantly reduce the total output capacitance requirement without sacrificing power factor, thus avoiding the need for electrolytic capacitors and enabling the use of long-life film capacitors. The circuits and methods are particularly suitable for use in applications where ripple-free high power and high reliability are required, such as in high power LED lighting.