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:
Mar. 04, 2014
Filed:
Jul. 20, 2011
Akinori Hiramatu, Nara, JP;
Hiromitsu Mizukawa, Suita, JP;
Akinori Hiramatu, Nara, JP;
Hiromitsu Mizukawa, Suita, JP;
Panasonic Corporation, Osaka, JP;
Abstract
A lighting device is provided for lighting control of an LED module based on an externally provided dimming control signal. A chopper circuit includes a switch coupled across a DC input and an inductor which receives and stores energy when the switch is turned on, and discharges energy to the LED module when the switch is turned off. A control circuit determines a current value to the switch, and compares the current value to a predetermined value. During normal operation, the switch is turned off when the detected current value reaches the predetermined value and turned back on when inductor discharge has completed. During a dimming operation, the normal operation is intermittently disabled in accordance with the dimming control signal. The dimming control signal may be a low-frequency PWM signal, with the lighting output being dimmed as a result of a duty ratio of the PWM signal.