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:
Oct. 19, 2010
Filed:
Feb. 29, 2008
Louis R. Nerone, Brecksville, OH (US);
Melvin C. Cosby, Jr., Grand River, OH (US);
Louis R. Nerone, Brecksville, OH (US);
Melvin C. Cosby, Jr., Grand River, OH (US);
General Electric Company, Schenectady, NY (US);
Abstract
In an instant start ballast, dimming control is provided over a range of operation in which lamps driven by the ballast do not require external cathode heating. An interface circuit () includes a winding () that is inductively coupled to windings () of an inverter circuit (). The interface circuit () also includes a variable impedance in parallel with the winding () where the variable impedance includes a transistor () and a Zener diode (). By varying an input voltage across control leads (), the apparent inductance of the winding () is varied. This variance affects the switching frequency of the inverter circuit () affecting the frequency of a drive signal provided to the lamps. Thus the instant start ballast can be dimmed without use of multiple ballasts and/or external cathode heating.