Patent US5446405A successfully refreshed from Google Patents.
US5446405A
Expired / Lapsed
US
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Amplifier circuit with offset cancel circuit
Assignee: Fujifilm Business Innovation Corp
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Filing: 1993-11-19
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Granted: 1995-08-29
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Expires: 2013-11-19
Abstract
Abstract In an amplifier circuit with an offset cancel circuit, on the output side of a non-inversion amplifier circuit, there is connected a sampling circuit including an analog switch composed of two MOS transistors. A source-follower circuit is connected to the output terminal of the sampling circuit. The output voltage of the source-follower circuit is applied to a series resistance formed between two resistances. A connecting point between the resistances is connected to the inversion input terminal of an operational amplifier forming the non-inversion amplifier circuit and thus the divisional component of the output signal of the source-follower circuit is applied to the inversion input terminal of the operational amplifier.
Inventors
- 👤 Chikaho Ikeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:18
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/30; H03F1/303
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
134 words
An amplifier circuit with an offset cancel circuit, comprising: a non-inversion amplifier circuit including an operational amplifier and a feedback resistance connected between an inversion input terminal and an output terminal of said operational amplifier an input to the non-inversion side of said non-inversion amplifier circuit; a sampling hold circuit connected to an output terminal of said non-inversion amplifier circuit; a source-follower circuit interposed between an output terminal of said sampling hold circuit and an inversion input terminal of said operational amplifier forming said non-inversion amplifier circuit; a first resistance which connects an output terminal of said source-follower circuit with the inversion input terminal of said operational amplifier; and a second resistance having one end held at a constant potential and the other end connected with the inversion input terminal of said operational amplifier.
Claim 2
Dependent Claim
134 words
An amplifier circuit with an offset cancel circuit, comprising: a non-inversion amplifier circuit including an operational amplifier and a feedback resistance connected between an inversion input terminal and an output terminal of said operational amplifier an input to the non-inversion side of said non-inversion amplifier circuit; a sampling hold circuit connected to an output terminal of said non-inversion amplifier circuit; a source-follower circuit interposed between an output terminal of said sampling hold circuit and an inversion input terminal of said operational amplifier forming said non-inversion amplifier circuit; a first resistance which connects an output terminal of said source-follower circuit with the inversion input terminal of said operational amplifier; and a second resistance having one end held at a constant potential and the other end connected with the inversion input terminal of said operational amplifier.
Claim 3
Dependent Claim
69 words
The amplifier circuit as set forth in claim 1, wherein a composite resistance value obtained when said second resistance is connected in parallel with a series resistance formed between said first resistance and an output resistance of said source-follower circuit is equal to a resistance value of a resistance when the inversion input terminal of said operational amplifier is connected with said source-follower circuit by means of said resistance.
Claim 4
Dependent Claim
88 words
The amplifier circuit as set forth in claim 1, wherein a value of a series resistance between said first resistance and an output resistance of said source-follower circuit is set two times or more than that of said second resistance, and a value of a feedback resistance of said operational amplifier is set two times or more than a composite resistance value obtained when said second resistance is connected in parallel with a series resistance formed between said first resistance and an output resistance of said source-follower circuit.
Claim 5
Dependent Claim
40 words
The amplifier circuit as set forth in claim 1, wherein a potential to be applied to one end of said second resistance is set substantially equal to an offset voltage included in an input signal of said non-inversion amplifier circuit.
Claim 6
Dependent Claim
54 words
The amplifier circuit as set forth in claim 1, wherein said sampling hold circuit includes an analog switch openable and closable in accordance with a logical signal and a capacitor connected in series with said analog switch, said capacitor being connected through said analog switch to the output terminal of said non-inversion amplifier circuit.
References Cited (Backward Citations)
US4255715A
Cited
US4430622A
Cited
US4578646A
Cited
US4962328A
Cited
US5087890A
Cited
US5229720A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-08-28 | 1999-02-27 | 1999-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-08-28 | 2003-02-27 | 2003-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-08-28 | 2007-02-27 | 2007-08-29 | $7700.00 | Window Closed / Lapsed |