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. 15, 2011
Filed:
Mar. 26, 2008
Peter Green, Redondo Beach, CA (US);
Peter Green, Redondo Beach, CA (US);
International Rectifier Corporation, El Segundo, CA (US);
Abstract
A ballast circuit operable to drive a high intensity discharge lamp in accordance with an embodiment of the present applications includes an energy conversion circuit operable to convert an input voltage into a bus voltage and to provide the bus voltage to a DC bus, a first half bridge connected across the DC bus and operable to control an output voltage supplied to the lamp, a control circuit operable to control the half bridge such that a desired output voltage is provided to the lamp, a series inductor connected in series between the half bridge and the lamp; and a parallel capacitor resistor connected across the lamp. The control circuit operates the half bridge at a high frequency for a set period of time such that a high voltage is built up across the parallel resistor, and then reduces the frequency of the half bridge until it approaches a resonance frequency which ignites the lamp.