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.:

US 9608581 B1

PDF
Full Text
Expired
Date of Patent:
Mar. 28, 2017

Filed:

Mar. 24, 2016
Applicant:

Sumitomo Electric Industries, Ltd., Osaka-shi, Osaka, JP;

Inventors:

Naoki Itabashi, Yokohama, JP;

Taizo Tatsumi, Yokohama, JP;

Keiji Tanaka, Yokohama, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03F 3/45 (2006.01); H03G 1/00 (2006.01); H03G 3/30 (2006.01);
U.S. Cl.
CPC ...
H03G 1/0023 (2013.01); H03F 3/45089 (2013.01); H03F 3/45618 (2013.01); H03G 1/0082 (2013.01); H03G 3/3084 (2013.01); H03F 2200/78 (2013.01); H03F 2203/45038 (2013.01); H03F 2203/45112 (2013.01);
Abstract

A differential amplifier includes an amplifying stage that outputs an output signal by amplifying an input signal with a gain set by a control signal, and an adjusting stage that stabilizes a DC level of the output signal. The amplifying stage includes a first source supplying a first current, and a load, and determines a ratio of a current flowing through the load to the first current depending on the input signal and the control signal, and generates the output signal from a voltage drop of the load. The adjusting stage includes a second source supplying a second current, and a monitor resistor, and generates a monitor current divided from the second current by the ratio, and duplicates the DC level as a voltage drop of the monitor resistor caused by the monitor current, and controls the first current source and the second current source depending on the DC level.


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