Patent ID: 8624500

Claim:
A power supply for providing a constant current to a light emitting diode (LED) load, the power supply comprising: a power controller receiving an alternating current (AC) input and providing a direct current (DC) output voltage controlled to maintain a constant feedback voltage, the DC output voltage provided to a high side of the LED load, the DC output voltage relative to a common power line coupled to a low side of the LED load and the power controller; a current sense resistor connected in series on the high side of the LED load; a current sensing circuit coupled across the current sense resistor providing a reference current at an output line proportional to a current sense voltage across the current sense resistor; and a current selector resistor coupled between the output line of the current sensing circuit and the common power line coupled to the low side of the LED load, the current selector resistor and the reference current generating a current-sensed voltage for use as the feedback voltage used by the power controller; wherein the DC output voltage provided by the power controller is controlled to provide a constant current to the LED load.