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:
Jul. 18, 2006
Filed:
Sep. 27, 2004
Cesare Bocchiola, Settimo, IT;
Cesare Bocchiola, Settimo, IT;
International Rectifier Corporation, El Segundo, CA (US);
Abstract
An HID ballast includes a flyback power converter with a simplified topology that permits power factor correction while supplying constant output power to drive an inverter supplying low frequency modulated power to the HID lamp. A switch is coupled in series with a transformer in the power converter to control current through the transformer to provide constant output power. The off time of the switch contributes to controlling the power factor of the ballast circuit. The transformer is operated in critical conduction mode, with an indication of zero current in the transformer used to determine the control for the switch. An output of the flyback power converter provides a feedback signal to obtain constant power output based on switching intervals applied to the switch coupled to the transformer. This simplified topology reduces part counts while providing a robust control that can be flexibly applied to a number of HID lamps.