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. 01, 2016
Filed:
Feb. 18, 2014
Citizen Holdings Co., Ltd., Nishitokyo-shi, Tokyo, JP;
Citizen Electronics Co., Ltd., Fujiyoshida-shi, Yamanashi, JP;
Keisuke Sakai, Matsudo, JP;
Takashi Akiyama, Sayama, JP;
Satoshi Goto, Yamanashi, JP;
Shigehisa Watanabe, Fujikawaguchiko-machi, JP;
Tatsuro Yamada, Fujiyoshida, JP;
CITIZEN HOLDINGS CO., LTD., Tokyo, JP;
CITIZEN ELECTRONICS CO., LTD., Yamanashi, JP;
Abstract
The purpose of the present invention is to provide an LED drive circuit that is capable of ameliorating insufficient lighting and improving power utilization efficiency. This LED drive circuit is an LED drive circuit wherein the number of LEDs that are turned on varies in accordance with the voltage of a commercial alternating-current power supply, the LED drive circuit being characterized by having an LED row in which multiple LEDs are connected in series, a current detection resistor for detecting a current that flows in the LED row, a bypass circuit that is connected to an intermediate connection part of the LED row, and a current-limiting circuit that is connected to an end of the LED row, wherein the bypass circuit includes a first current-limiting component, the current-limiting circuit includes a second current-limiting component, the first current-limiting component is controlled on the basis of a voltage across the ends of the current detection resistor or a voltage that is obtained by dividing the voltage across the ends of the current detection resistor, and the second current-limiting component is controlled by the divided voltage that is obtained by dividing the current detection resistor.