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:
Nov. 25, 2014
Filed:
Aug. 27, 2012
Wei Xiong, Madison, AL (US);
John J. Dernovsek, Madison, AL (US);
Candice Ungacta, Huntsville, AL (US);
Danny Pugh, Harvest, AL (US);
Wei Xiong, Madison, AL (US);
John J. Dernovsek, Madison, AL (US);
Candice Ungacta, Huntsville, AL (US);
Danny Pugh, Harvest, AL (US);
Universal Lighting Technologies, Inc., Madison, AL (US);
Abstract
A ballast is designed to adaptively warm-up one or more lamps driven by the ballast when the lamps are dimmed to a selected dimming level and lamp impedance instability results. The ballast can therefore maintain a stable light output in low ambient temperature conditions that normally cause lamp impedance instability and visible flickering of the lamp. The ballast uses lamp impedance sensing circuit to sense lamp instability and adaptively warms up the lamp whenever the ballast detects lamp instability by increasing the current provided to the lamp (i.e., current through the lamp) for a predetermined period of time.