This invention presents a single-stage power converter for driving many number of Light-Emitting-Diode (LED). The power converter converts an AC input voltage into DC current source and regulates the current flowing into the LED. In addition, the AC input current is controlled to have a sinusoidal waveform...http://www.google.com/patents/US7378805?utm_source=gb-gplus-sharePatent US7378805 - Single-stage digital power converter for driving LEDs
