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. 20, 2011
Filed:
Aug. 08, 2008
Toru Ashikaga, Saitama, JP;
Kazushige Hirata, Saitama, JP;
Toru Ashikaga, Saitama, JP;
Kazushige Hirata, Saitama, JP;
Sanken Electric Co., Ltd., Saitama, JP;
Abstract
A discharge lamp lighting device is provided to comprise tube current detecting circuitstofor outputting detection signals Vto Vof tube currents Ito Iflowing through each discharge lamptofrom an inverterconnected to DC power sourcevia a plurality of transformersto, a maximum detectorfor detecting a maximum value Vof detected signals Vto Vfrom current detectorto, a minimum detectorfor detecting a minimum value Vof detected signals Vto Vfrom current detectorto, a comparison circuitfor computing one or plural values of sum, difference, product and quotient between maximum value Vfrom maximum detectorand minimum value Vfrom minimum detectorto generate a cease signal Vwhen the computed value exceeds a given value, and a control circuitfor halting operation of inverterwhen comparison circuitgenerates cease signal V. The device can reliably detect arc discharge resulted from electric connection failure in discharge lamp or lamps by the computed values from comparison circuitto positively protect discharge lamps from overheating by arc discharge at a bad connection location.