The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 17, 1998
Filed:
Jun. 14, 1996
Robert J Vitello, Duluth, GA (US);
Loral Corporation, New York, NY (US);
Abstract
A system wherein light from a fluorescent lamp is dimmed by modulating the pulse-width of current pulses. A current-command signal is applied to a lamp driver in response to a voltage-level corresponding to a given, selectable level of desired lamp brightness. The lamp driver operates as a flyback AC power source that advantageously uses a FET switch to decouple the lamp and a resonant bridge, with the current-sampling process. The circuit samples only the inductor current while the FET switch is active. Because the sample is decoupled from the lamp and bridge, this sampling provides particularly tight control of the regulation process needed to control the incoming noise and transients that affect the power supplied to the lamps. The lamp driver a can also operate as a synchronously-driven resonant forward converter that senses the current actually supplied to the lamp and responds to changes in the fluorescent lamp's condition since the lamp is coupled to the circuit.