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:
Dec. 11, 2012
Filed:
Jan. 27, 2010
Naoki Komatsu, Hyogo, JP;
Naoki Komatsu, Hyogo, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An electronic ballast for powering a discharge lamp includes an asymmetry determination circuit functional to determine whether positive and negative polarities of an AC output current to the lamp are symmetrical. An inverter having a plurality of switching elements is coupled to a DC power source and converts the DC power to the AC output current. A control circuit is functional to control the plurality of switching elements dependent upon an operating mode and an output from the asymmetry determination circuit. The control circuit controls the switching elements in a normal mode upon receiving a determination of symmetrical current from the asymmetry determination circuit, and controls the switching elements in a restart mode for a predetermined period of time upon receiving a determination of asymmetrical current from the asymmetry determination circuit.