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:
Nov. 29, 2016
Filed:
Oct. 24, 2015
Renesas Electronics Corporation, Tokyo, JP;
Makoto Nakamura, Tokyo, JP;
Motoaki Suzuki, Tokyo, JP;
Mamoru Kitamura, Tokyo, JP;
Keisuke Fukuda, Tokyo, JP;
Renesas Electronics Corporation, Tokyo, JP;
Abstract
A voltage conversion unit including a coil and a first switch converts an AC voltage into a first voltage, which is a DC voltage, by controlling the first switch to be on in an on-pulse period of a first drive signal. A constant current drive unit is supplied with the first voltage and generates a drive current Id having a current value according to light control information. An LED control unit compares brightness based on the light control information and reference brightness, generates a first drive signal based on an error between the first voltage and a target voltage representing a target of the first voltage, when the brightness is higher than the reference brightness, and generates the first drive signal having a predetermined fixed on-pulse period when the brightness is lower than the reference brightness.