Described herein are methods and circuits for improving the performance of an AC to DC power supply. The methods and circuits achieve high power factor (PF) at the AC side and at the same time, reduce or substantially eliminate ripple in the DC output power. The methods and circuits provide an isolated topology including primary side voltage and current sensing and primary side ripple cancellation control. The methods and circuits may be used in any application where high power factor and/or low output ripple are required. In particular, the methods and circuits may be used in DC lighting applications, such as in light emitting diode (LED) lighting, wherein suppression of low frequency ripple in the output power eliminates visible flickering.