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. 01, 2019
Filed:
Sep. 27, 2016
Citizen Watch Co.,ltd., Nishitokyo-shi, Tokyo, JP;
Citizen Electronics Co., Ltd., Fujiyoshida-shi, Yamanashi, JP;
Keisuke Sakai, Yamanashi, JP;
Takashi Akiyama, Sayama, JP;
CITIZEN WATCH CO., LTD., Nishitokyo-Shi, Tokyo, JP;
CITIZEN ELECTRONICS CO., LTD., Fujiyoshida-Shi, Yamanashi, JP;
Abstract
An LED drive circuit in which a bright change of an LED is suppressed even if the voltage of a full-wave rectified waveform fluctuates is provided. The LED drive circuit includes a bridge rectifier circuit, an LED string made up by a plurality of LEDs being connected in series and supplied with a current from the bridge rectifier circuit, and a current limiting circuit that has a current input terminal and a current output terminal connected onto a path that starts from the bridge rectifier circuit and returns to the bridge rectifier circuit via the LED string, which limits a current that flows through the LED string to an upper limit current value or smaller, and further, which decreases the upper limit current value in accordance with the amount of rise in the voltage when the voltage at the current input terminal viewed from the current output terminal rises.