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:
Dec. 04, 2007
Filed:
Mar. 23, 2005
Applicants:
Tomoyuki Ito, Kyoto, JP;
Isao Yamamoto, Kyoto, JP;
Inventors:
Tomoyuki Ito, Kyoto, JP;
Isao Yamamoto, Kyoto, JP;
Assignee:
Rohm Co., Ltd., , JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02M 3/18 (2006.01); H02M 7/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
When a step-up ratio control circuit sets a step-up ratio of a charge pump circuit to 1.0 to enable a short mode, a path inside the charge pump circuit is short-circuited and a first transistor is completely turned on. This produces an inrush current derived from a battery voltage of a lithium ion battery flowing into the charge pump circuit. To address this, a constant current circuit is operated so that the first transistor is turned on slowly. Further, the operation of an oscillator and an operational amplifier is suspended when the short mode is enabled.