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:
Apr. 05, 2016
Filed:
Jul. 18, 2014
Universal Lighting Technologies, Inc., Madison, AL (US);
Stephen D. Mays, II, Madison, AL (US);
John J. Dernovsek, Madison, AL (US);
Brandon Dyer, Huntsville, AL (US);
Danny Pugh, Harvest, AL (US);
Universal Lighting Technologies, Inc., Madison, AL (US);
Abstract
A high efficiency electronic ballast or driver circuit provides striation control at reduced power levels. The driver circuit includes a controller operating a half-bridge inverter to drive a resonant tank circuit. The controller provides asymmetric on-times to upper and lower switches of the half-bridge inverter when operating at low duty cycles (e.g., duty cycles of 50% or less). The resulting asymmetric output current eliminates striation in lamps driven by the ballast. In order to maintain light output (i.e., output current), the controller reduces the operating frequency of the half-bridge inverter to increase the gain and impedance of the resonant tank circuit.