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. 28, 2014
Filed:
Feb. 25, 2011
Shunji Egawa, Tokorozawa, JP;
Isao Ochi, Tokorozawa, JP;
Shunji Egawa, Tokorozawa, JP;
Isao Ochi, Tokorozawa, JP;
Citizen Holdings Co., Ltd., Tokyo, JP;
Abstract
The invention is directed to the provision of an LED driving circuit that switches the connection of LED blocks in accordance with the supply voltage and the Vf's specific to individual LEDs contained in each LED block. The LED driving circuit includes a rectifier; a first circuit, a first current detection unit for detecting current flowing from the first LED array to the negative output of the rectifier, and a first current limiting unit for limiting the current flowing from the first LED array to the negative output of the rectifier in accordance with the current detected by the first current detection unit, and a second circuit which includes a second LED array and a current path passing through the second LED array and leading to the negative output of the rectifier, and wherein a current path in which only the first LED array is connected to the rectifier and a current path are formed in accordance with an output voltage of the rectifier, and the first current detection unit, upon detecting current flowing through the first and second LED arrays, operates the first current limiting unit to perform current path switching.