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:
Sep. 24, 1991
Filed:
Jun. 21, 1990
Robert L Garrison, Henniker, NH (US);
Harold L Rothwell, Georgetown, MA (US);
GTE Products Corporation, Danvers, MA (US);
Abstract
A ballast for starting and operating a high intensity discharge (HID) lamp in a dc mode includes an oscillator coupled to first and second direct current input terminals. The oscillator includes a high frequency generator driving a pair of semiconductor switches. A first transformer having primary and secondary windings is coupled to the semiconductor switches. A rectifier and voltage multiplier circuit converts the voltage across the secondary winding of the first transformer to a dc voltage. A first energy storage circuit coupled to the rectifier and voltage multiplier circuit stores energy for generating a negative-going, high-voltage spike sufficient for initiating a glow condition in the lamp. A second energy storage circuit, which stores energy for application to the HID lamp during starting, insures proper glow-to-arc transition. The starting and operating circuit further includes a control circuit for regulating lamp power in response to control signals received from voltage and current monitoring circuits. A portion of the ballast is adapted to permit the lamp to reach full light output in a relatively short period of time by briefly operating the lamp at an elevated power level during starting.