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:
Jun. 10, 1997

Filed:

Jul. 28, 1995
Applicant:
Inventor:

Masaru Hashimoto, Yokohama, JP;

Assignee:

Kabushiki Kaisha Toshiba, Kawasaki, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03F / ; G11B / ;
U.S. Cl.
CPC ...
330260 ; 330261 ; 330156 ; 360 67 ;
Abstract

A high input impedance circuit includes an amplifier such as an operational amplifier comprising transistors of a first polarity which serve as a differential pair and input of the amplifier, base of one transistor being caused to serve as a positive input terminal, base of the other transistor being caused to serve as a negative input terminal. The high input impedance circuit further includes a transistor having base connected to the positive input terminal, and a second polarity opposite to the first polarity, wherein collector of the transistor of the second polarity is connected through d.c. path to a first power supply, e.g., ground, and emitter of the transistor of the second polarity is connected through d.c. path to a second power supply, e.g., power supply voltage terminal through a resistor to apply a signal in phase with an input signal delivered to the positive input terminal to the emitter of the transistor of second polarity to thereby allow input impedance to be higher. In addition, a semiconductor device provided with such a high input impedance circuit is also provided.


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