Patent ID: 6107755
Filing Date: 2000-08-22
Classification: H05B

Abstract:
An electronic ballast for exciting a gas-discharge lamp to produce a varying light output level related to a variable lamp current provided thereto, comprising:a) a ballast circuit for providing a variable output lamp current responsive to an input signal;b) lamp current monitoring means operatively connected to said ballast circuit for producing a lamp current signal representative of said lamp current;c) a first feedback path between said ballast circuit and said lamp current monitoring means operable primarily when said lamp current is within a first, predetermined range of lamp current values;d) a second, parallel feedback path between said ballast circuit and said lamp current monitoring means operable primarily when said lamp current is within a second, predetermined range of lamp current values; ande) means for generating a control signal operatively connected to said ballast circuit and operating cooperatively with said first feedback and said second feedback path to set a specific output lamp current value and a specific light output level related thereto, by providing said input signal to said ballast circuit;whereby said specific output lamp current and said related specific light output level is maintained at a substantially constant level.