Patent ID: 6798153
Filing Date: 2004-09-28
Classification: H05B

Abstract:
A system of controlling power to a high-intensity-discharge lamp, said system comprising:a voltage sensor operable to generate a first sensing voltage indicative of a voltage across the lamp; a current sensor operable to generate a second sensing voltage indicative of a current through the lamp; and a control circuit operable to approximate a lamp power as a function of the first sensing voltage and the second sensing voltage, to compare the approximated lamp power and a reference voltage, and to regulate the power to the lamp based on the comparison of the approximated lamp power and the reference voltage, wherein said control circuit includes a summing circuit operable to generate a summation voltage as a function of a summation of the first sensing voltage and the second sensing voltage, the summation voltage being indicative of the approximated lamp power; wherein said voltage sensor is in electrical communication with said control circuit to apply the first sensing voltage to said control circuit, and wherein said current sensor is in electrical communication with said control circuit to apply the second sensing voltage to said control circuit.