A power factor correction circuit, and methods of operation, is described, that can downconvert AC mains power to a lower power suitable for driving one or more LEDs. The power factor correction circuit can provide a regulated current, in a single-stage embodiment, and a regulated voltage, in a dual-stage embodiment. The power factor correction circuit can include an isolation transformer along with a switch for controlling downconversion. The power factor correction circuit can alternatively include a switch without isolation. Either way, the switch can have a duty cycle proportional to a desired downconversion from the AC mains signal, and can skip half cycles of the AC mains signal in order to reduce the downconverted output of the power factor correction circuit.