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:
May. 17, 2011
Filed:
May. 12, 2009
Afroz M. Imam, Danvers, MA (US);
Sivakumar Thangavelu, Billerica, MA (US);
Mustansir Kheraluwala, Lake Zurich, IL (US);
Afroz M. Imam, Danvers, MA (US);
Sivakumar Thangavelu, Billerica, MA (US);
Mustansir Kheraluwala, Lake Zurich, IL (US);
Osram Sylvania Inc., Danvers, MA (US);
Abstract
A ballast including an H-bridge type inverter for driving a lamp and a filter circuit that includes a buck inductor is disclosed. The buck inductor is a primary winding of a transformer, and a secondary winding of the transformer provides power to a controller of the ballast. The controller operates the inverter in various pre-ignition modes of operation such that prior to ignition, the open circuit voltage (OCV) (i.e., voltage across the lamp) and buck inductor current are controlled to transfer sufficient power from the primary of the transformer to the secondary winding of the transformer to power the controller. No switches of the inverter are turned on while there is a non-zero current through the filter circuit.