DIFFERENTIAL CIRCUIT

• US 20130120027A1
• Filed: 09/05/2011
• Published: 05/16/2013
• Est. Priority Date: 09/15/2010
• Status: Active Grant

• Current Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Original Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Inventors: Inoue, Fumihiro
• Granted Patent: US 8,749,275 B2
• Time in Patent Office: Days
• US Class Current: 327/82
• CPC Class Codes: H03F 2203/45356 the AAC comprising one or more op-amps, e.g. IC-blocks
• CPC Class Codes: H03F 3/45192 Folded cascode stages
• CPC Class Codes: H03K 3/0231 Astable circuits H03K3/0315 takes precedence
• CPC Class Codes: H03K 5/24 the characteristic being amplitude
• CPC Class Codes: H03K 5/2481 with at least one differential stage

Abstract

A differential circuit characterized by including a first input part to which a first input voltage is input; a second input part to which a second input voltage is input; a reference voltage input part to which a reference voltage is input, the reference voltage input part being common to form differential pairs by pairing with respective ones of the first input part and the second input part; a current source that drives the differential pairs; a current mirror that generates a first output current and a second output current, according to a current that flows through the reference voltage input part according to at least one voltage difference of a first voltage difference between the first input voltage and the reference voltage and a second voltage difference between the second input voltage and the reference voltage; a first output part that outputs a signal according to the first voltage difference, according to a current that flows through the first input part according to the first voltage difference and the first output current; and a second output part that outputs a signal according to the second voltage difference, according to a current that flows through the second input part according to the second voltage difference and the second output current.

Claims

1. A differential circuit comprising:

a first input part to which a first input voltage is input;

a second input part to which a second input voltage is input;

a reference voltage input part to which a reference voltage is input, the reference voltage input part being common to form differential pairs by pairing with respective ones of the first input part and the second input part;

a current source that drives the differential pairs;

a current mirror that generates a first output current and a second output current, according to a current that flows through the reference voltage input part according to at least one voltage difference of a first voltage difference between the first input voltage and the reference voltage and a second voltage difference between the second input voltage and the reference voltage;

a first output part that outputs a signal according to the first voltage difference, according to a current that flows through the first input part according to the first voltage difference and the first output current; and

a second output part that outputs a signal according to the second voltage difference, according to a current that flows through the second input part according to the second voltage difference and the second output current.

2. The differential circuit as claimed in claim 1, used as an operational amplifier.

3. The differential circuit as claimed in claim 2, used as the operational amplifier that increases output impedances of plural cascode circuits of an output stage of an operational amplifier circuit.

4. The differential circuit as claimed in claim 2, comprising:

a first negative feedback circuit provided between the first output part and the first input part; and

a second negative feedback circuit provided between the second output part and the second input part.

5. The differential circuit as claimed in claim 1, wherein

the current source has a cascode current source.

6. The differential circuit as claimed in claim 1, wherein

the first output part and the second output part have cascode current sources.

7. The differential circuit according to claim 2, used in an integrating circuit.

8. The differential circuit according to claim 2, used in an amplifier circuit.

9. The differential circuit according to claim 2, used in an filter circuit.

10. The differential circuit according to claim 1, used as a comparator.