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:
Jan. 15, 2013
Filed:
Sep. 01, 2010
Hirokazu Otake, Yokosuka, JP;
Mitsuhiko Nishiie, Yokosuka, JP;
Takuro Hiramatsu, Yokosuka, JP;
Keiichi Shimizu, Yokosuka, JP;
Hirokazu Otake, Yokosuka, JP;
Mitsuhiko Nishiie, Yokosuka, JP;
Takuro Hiramatsu, Yokosuka, JP;
Keiichi Shimizu, Yokosuka, JP;
Toshiba Lighting & Technology Corporation, Kanagawa, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
In a power supply device according to one embodiment, a reference signal (Vref), which changes from a value corresponding to a maximum current in a full lighting state to that corresponding to a minimum current in case of a deepest dimming depth, and a reference signal (Vref), which changes from a value corresponding to a load voltage at the time of a maximum current in a full lighting state to that corresponding to a minimum current in case of the deepest dimming depth, are prepared in accordance with dimming depths of a dimming signal. In a shallow dimming depth region close to a full lighting state, the reference signal (Vref) is selected to apply constant-current control to light-emitting diodes in a current control mode. In a deep dimming depth region, the reference signal (Vref) is selected to apply constant-voltage control to the diodes in a voltage control mode.