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:
Apr. 29, 2014
Filed:
Oct. 17, 2011
Takafumi Nonaka, Tokyo, JP;
Takashi Kumagai, Tokyo, JP;
Yuichiro Ito, Tokyo, JP;
Haruka Kinoshita, Tokyo, JP;
Shinsuke Funayama, Kanagawa-ken, JP;
Takashi Maeda, Kanagawa-ken, JP;
Takafumi Nonaka, Tokyo, JP;
Takashi Kumagai, Tokyo, JP;
Yuichiro Ito, Tokyo, JP;
Haruka Kinoshita, Tokyo, JP;
Shinsuke Funayama, Kanagawa-ken, JP;
Takashi Maeda, Kanagawa-ken, JP;
Mitsubishi Electric Corporation, Chiyoda-Ku, Tokyo, JP;
Abstract
A power supply circuit drives circuits having different numbers of series-connected LEDs without changing a circuit constant or a component. An LED series circuit is connected to a power converter circuit of a power supply circuit. The power converter circuit is controlled by a control arithmetic circuit, and supplies a constant current to the LED series circuit. A voltage detection circuit detects a voltage applied to the LED series circuit. The control arithmetic circuit checks whether the LED series circuit has 40 LEDs or 20 LEDs, based on the voltage detected by the voltage detection circuit. The control arithmetic circuit holds a constant-current value table for 40 LEDs and a constant-current value table for 20 LEDs. In accordance with the detected voltage, the control arithmetic circuit selects one constant-current value table, and controls the power converter circuit based on the constant-current value table selected.