Electrodless fluorescent lamp light regulating system

Application Number: 00108989
Application Date: 2000.05.25
Publication Number: 1293531
Publication Date: 2001.05.02
Priority Information: 1999/5/25 US 09/318343
International: H05B41/36
Applicant(s) Name: General Electric Co.
Inventor(s) Name: L.R. Neroni
Patent Agency Code: 72001
Patent Agent: luo peng
Abstract A ballast 10 for an electrodeless gas discharge lamp 30, incorporates a dimming circuit 12. Ballast 10 includes a load circuit 20 having an radio frequency inductor 32 for generating an radio frequency field to power electrodeless lamp 30. A voltage of an inductor 56 in a d.c.-to-a.c. converter 13 of ballast 10 is sensed by dimming circuit 12. Dimming circuit 12, which uses frequency-shift keying (FSK), couples inductor 56 to the dimming circuit 12 via dimming inductor 80, which in turn is connected to serially arranged dimming switches 82, 84. A signal generator 86 activates dimming switches 82 and 84 to provide a frequency shift to ballast 10. This frequency shift lowers the output to radio frequency inductor 32, thereby turning off electrodeless lamp 30. Repeated switching by dimming circuit 12 causes a visual dimming in electrodeless lamp 30.