Patent ID: 6011362
Filing Date: 2000-01-04
Classification: H05B,Y10S

Abstract:
An apparatus for coupling a source signal from a power source to a lamp, the source signal having a first source signal frequency and a first source signal amplitude and the apparatus comprising:a ballast having first and second ballast input terminals coupled to first and second power terminals of the power source and first and second ballast output terminals coupled to first and second terminals of the lamp, said ballast for receiving the source signal and for providing at the first and second ballast output terminals, a ballast signal having a first ballast signal frequency and a first ballast signal amplitude; andan adapter circuit having a first terminal coupled to the first output terminal of said ballast and a second terminal coupled to the second output terminal of said ballast, the adapter circuit for receiving the ballast signal having the first ballast signal frequency and the first ballast signal amplitude and for providing a drive signal to the lamp, the drive signal having a first drive signal frequency and a first drive signal amplitude, wherein the first drive signal is responsive to a feedback signal which corresponds to the ballast signal,wherein said adapter circuit includesa switching device having a first terminal coupled to the first terminal of said adapter circuit and a second terminal coupled to the second terminal of said adapter circuit thereby providing a signal path between the first and second terminals of said adapter circuit, said switching device having a first impedance characteristic in response to a first control signal having a first signal level and a second different impedance characteristic in response to the control signal having a second different signal level.