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. 07, 2007

Filed:

Sep. 14, 2005
Applicant:

Eiji Nishimori, Kasugai, JP;

Inventor:

Eiji Nishimori, Kasugai, JP;

Assignee:

Fujitsu Limited, Kawasaki, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03F 1/02 (2006.01);
U.S. Cl.
CPC ...
Abstract

An operational amplifier that cancels offset voltage while enabling its gain to be set to any value. The operational amplifier includes a first switch for short-circuiting the gates of two transistors in a first differential input unit. A capacitor is connected to the gates of two transistors in a second differential input unit, which is connected in parallel to the first differential input unit. The capacitor holds offset voltage derived from output voltage generated by an operational amplifier circuit. The capacitor generates a potential difference between the gates of the transistors in the second differential input unit to cancel the offset voltage.


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