Patent ID: 6577078
Filing Date: 2003-06-10
Classification: H05B,Y02B,Y10S

Abstract:
An electronic ballast, comprising:an input stage coupled to an AC source, the input stage converting an AC voltage to a direct current bus voltage; an output stage having inputs coupled to the bus voltage, outputs connected to a lamp, and an inductor in series with the lamp, the output stage operating with substantially constant on-time control providing (i) power to the lamp so as to produce a lamp voltage and lamp current in a steady state mode of operation, and (ii) a lamp run-up current to the lamp during a run-up phase of the operation of the lamp; and a current regulation circuit monitoring the current through said inductor to cause the lamp run-up current to exceed a steady state lamp current value and to increase lamp run-up current if either the bus voltage increases or the lamp voltage decreases.