04370600 is referenced by 98 patents and cites 8 patents.

A low cost, high frequency, solid-state dimmable fluorescent ballast is disclosed which utilizes a resonant bridge inverter to provide high frequency sinusoidal power to the lamps. One embodiment of the invention includes auxiliary windings connected to the filaments of the lamps to be powered which utilize the inductance of the resonant bridge inductor coil to maintain the voltage across the filaments during dimming. A clamping circuit or auxiliary tuned circuit may be provided to prevent damage due to an over-voltage and over-current condition upon removal of a lamp during operation of the system. In an alternative embodiment, the auxiliary windings, are replaced by capacitors across each of the lamps to be powered. This also eliminates the need for the clamping circuit. If desired, a current splitting capacitance system may be used. Pulse width modulation of the inverter drive or variable AC or DC power supply input may be used to accomplish dimming.

Title
Two-wire electronic dimming ballast for fluorescent lamps
Application Number
6/210651
Publication Number
4370600
Application Date
November 26, 1980
Publication Date
January 25, 1983
Inventor
Zoltan Zansky
Roseville
MN, US
Agent
Charles G Mersereau
Assignee
Honeywell
MN, US
IPC
H05B 41/392
H05B 41/29
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