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:
Aug. 21, 2012
Filed:
Jun. 23, 2009
Uwe Liess, Treviso, IT;
Naveen Yadlapalli, Billerica, MA (US);
Uwe Liess, Treviso, IT;
Naveen Yadlapalli, Billerica, MA (US);
OSRAM SYLVANIA Inc., Danvers, MA (US);
Abstract
A ballast () for powering one or two gas discharge lamps () includes an inverter (), an output circuit (), and a control circuit (). During a period prior to startup of inverter (), control circuit () monitors a signal within output circuit () in order to determine the presence of lamps with intact filaments that are present at the ballast output connections (). Preferably, control circuit () is realized by a programmable microcontroller which implements a dual timing scheme in order to accurately determine the number of lamps with both filaments intact. The resulting determination may be used for various purposes, such providing appropriate levels of filament heating and/or for setting thresholds for accurately detecting and protecting against various lamp fault conditions.