This reference design presents an alternative to the typical boost power regulator. A buck converter IC is used to generate a higher voltage needed by the white light LED power from a Ni-Cd battery. This circuit operates by turning the high switch on, connecting the battery voltage across the inductor. Once sufficient energy is stored in the inductor, the high side switch is turned off. The inductor current drives the switching node negative and energy is delivered through the low side into the output capacitor. This is essentially a lossless switching event. Also, since the high side and low side switches are MOSFET's, voltage drop can be very low as compared to a diode implementation so efficiency can be high. Regulation is achieved by monitoring the current through the LED with a current sense resistor and comparing it to an internal 0.45 volt reference within the converter IC. Current and thereby, illumination is varied by modifying the current sense resistor voltage.