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:
May. 20, 2014
Filed:
May. 19, 2010
Applicants:
Masao Yonemaru, Kyoto, JP;
Naoki Inoue, Kyoto, JP;
Hiroyuki Ishikawa, Kyoto, JP;
Inventors:
Assignee:
Rohm Co., Ltd., , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G06F 3/038 (2013.01); H05B 33/08 (2006.01);
U.S. Cl.
CPC ...
H05B 33/0818 (2013.01); H05B 33/0827 (2013.01); H05B 33/0887 (2013.01); Y02B 20/341 (2013.01); Y02B 20/347 (2013.01);
Abstract
A pulse modulator generates a first pulse signal having a duty ratio which is adjusted such that a detection voltage which indicates the electrical state of an LED string to be driven matches a predetermined reference voltage. A first pulse signal is applied to a primary coil of a pulse transformer. A DC/DC converter includes a switching element the ON/OFF operation of which is controlled according to a signal that originates at a secondary coil of the pulse transformer. The DC/DC converter stabilizes an input voltage Vdc, and supplies the input voltage Vdc thus stabilized to the anode of the LED string.