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. 29, 2013
Filed:
Apr. 19, 2011
Applicants:
Daisuke Uchimoto, Kyoto, JP;
Naoki Inoue, Kyoto, JP;
Yoju Imamura, Kyoto, JP;
Inventors:
Assignee:
Rohm Co., Ltd., , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H05B 37/02 (2006.01); H05B 41/36 (2006.01);
U.S. Cl.
CPC ...
Abstract
A control IC controls a switching power supply configured to supply a driving voltage Vout to one terminal of an LED string which is driven in an intermittent manner. A sample-and-hold circuit performs sampling of a detection voltage Vs that corresponds to a driving voltage Vout in the on period, and holds the sampled detection voltage Vs in the off period. In the off period, a pulse modulator generates a pulse signal having a duty ratio adjusted such that a hold detection voltage VsH output from the sample-and-hold circuit matches the detection voltage Vs. A driver drives a switching transistor according to the pulse signal.