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:
Oct. 07, 2014
Filed:
Dec. 20, 2011
Katsunobu Hamamoto, Osaka, JP;
Masafumi Yamamoto, Kyoto, JP;
Keisuke Ueda, Osaka, JP;
Hisaya Takikita, Osaka, JP;
Katsunobu Hamamoto, Osaka, JP;
Masafumi Yamamoto, Kyoto, JP;
Keisuke Ueda, Osaka, JP;
Hisaya Takikita, Osaka, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An LED lighting device includes a DC/DC power converter having output terminals coupled to respective lamp sockets. A controller receives signals from a current sensor and a voltage sensor, and controls the DC/DC power converter to increase/decrease an output voltage based on a sensed output current with respect to a target value. A sensed output voltage is compared to predetermined upper and lower limit values, and the DC/DC power converter is disabled when the output voltage exceeds the predetermined upper limit value or falls below the predetermined lower limit. The controller further measures an accumulated lighting time of the device, and after the accumulated lighting time has exceeded a predetermined switching time, decreases the upper limit value monotonously or in increments as the accumulated lighting time passes.