Patent ID: 6784622
Filing Date: 2004-08-31
Classification: H05B

Abstract:
An electronic ballast for driving at least one gas discharge lamp from a source of AC power which has a substantially sinusoidal line voltage at a given line frequency, comprising:a rectifying circuit having AC input terminals and DC output terminals, said AC input terminals connectable to said source of AC power, said rectifying circuit producing a rectified output voltage at its said DC output terminals when said AC input terminals are energized by said source of AC power; a valley fill circuit having input and output terminals; said input terminals of said valley fill circuit connected to said DC output terminals of said rectifying circuit; an inverter circuit having input terminals and output terminals; said input terminals of said inverter circuit connected to said output terminals of said valley fill circuit and said output terminals of said inverter circuit connectable to said at least one gas discharge lamp and producing a high frequency drive voltage for driving a lamp current through said at least one gas discharge lamp when said AC input terminals are energized by said source of AC power; said inverter circuit comprising a single controllably conductive device and an inductor; said inductor connectable to said at least one gas discharge lamp; said inverter circuit being adapted to draw current from said source of AC power whereby the total current drawn from said source of AC power has a total harmonic distortion below about 33.3%; and whereby the lamp current has a current crest factor below about 2.1.