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:
Sep. 17, 2013
Filed:
Aug. 25, 2011
Hideo Matsuda, Osaka, JP;
Atsushi Kanamori, Osaka, JP;
Takayuki Shimizu, Osaka, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
An LED drive circuit is provided that is connectable to a phase-control light controller and drives an LED load by use of a voltage obtained by rectifying a phase-controlled alternating current voltage inputted from the phase-control light controller. The LED drive circuit includes: a first phase angle detection portion that detects a phase angle in a present cycle; a second phase angle detection portion that detects a phase angle in a cycle preceding the present cycle by at least one cycle; a bias portion that generates a detection signal by adding a predetermined delay time to a phase angle obtained by averaging the phase angle detected by the first phase angle detection portion and the phase angle detected by the second phase angle detection portion; and a drive portion that starts current supply to the LED load at timing based on the detection signal generated by the bias portion.