US 2016/0190998 A1Published application

Amplifier circuit

AssigneeAlps Electric Co., Ltd.

InventorsKiyoshi Sasai, Akira Asao

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Abstract

A differential signal is input to a pair of gates of a differential pair, a differential signal generated by a load circuit connected to drains of the differential pair is amplified by a differential amplifier stage, and the amplified differential signal is fed back to a pair of sources of the differential pair via a feedback circuit. It is possible to maintain a high input impedance in the pair of gates of the differential pair while not being influenced by a gain of negative feedback of an amplifier circuit, and it is possible to perform amplification in an input stage by using a pair of a first transistor and a second transistor of the differential pair. Therefore, compared with the related art, it is possible to decrease the number of transistors in the input stage and to reduce a flicker noise.

Claims6

Dependent claims

An amplifier circuit comprising:

a differential pair including a pair of a first transistor and a second transistor, wherein each of the first transistor and the second transistor is a transistor in which, in response to a voltage between a control terminal and a first terminal, a current flowing between the first terminal and a second terminal is controlled, and a differential signal is input to a pair of the control terminals included in the pair of the first transistor and the second transistor;
a load circuit configured to generate a differential signal corresponding to currents flowing through a pair of the second terminals included in the pair of the first transistor and the second transistor in the differential pair;
an output amplifier stage configured to amplify and output the differential signal generated by the load circuit;
and
a feedback circuit configured to feed the differential signal output by the output amplifier stage back to a pair of the first terminals included in the pair of the first transistor and the second transistor in the differential pair.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/065,066Filed 9 Mar 2016
Priority: JP 2013-19091713 Sep 2013
Published: 30 Jun 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification17 codes

H03F 1/26
Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements: modifications of…
H03F 3/393
With semiconductor devices only: with field-effect devices
H03F 3/45197
Using MOSFET transistors as the active amplifying circuit: pl types
H03F 3/4565
Measuring at the loading circuit of the differential amplifier: controlling the common source circuit of the differential amplifier