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.

Date of Patent:
Aug. 10, 2010

Filed:

Jan. 11, 2007
Applicants:

Tsugunori Okuda, Osaka, JP;

Akihito Nagahama, Osaka, JP;

Inventors:

Tsugunori Okuda, Osaka, JP;

Akihito Nagahama, Osaka, JP;

Assignee:

Ricoh Company, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G05F 1/569 (2006.01);
U.S. Cl.
CPC ...
Abstract

A constant voltage circuit is disclosed that includes an output voltage control transistor outputting a current to an output terminal; a first error amplifier circuit part controlling the operation of the output voltage control transistor; a second error amplifier circuit part causing the output voltage control transistor to increase the output current when there is a rapid decrease in an output voltage from the output terminal; and a current limiting circuit part controlling the operation of the output voltage control transistor so as to prevent the output current therefrom from exceeding a first predetermined value by gradually decreasing the output current and the output voltage alternately when the output current is greater than or equal to the first predetermined value. The current limiting circuit part stops the operation of the second error amplifier circuit part when the output voltage is less than or equal to a second predetermined value.


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