US5023567A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stability-compensated operational amplifier
Assignee: Western Digital Corp
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Filing: 1990-06-06
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Granted: 1991-06-11
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Expires: 2010-06-06
Abstract
Abstract A stability-compensated, integrated-circuit operational amplifier has an open-loop gain versus frequency characteristic which provides stable and accurate closed-loop operation in numerous overall circuits including a CMOS circuit for producing a precision current as a reference to a digital-to-analog converter. The operational amplifier comprises an inverting node and a non-inverting node, and CMOS circuitry defining two differential amplifiers. Each differential amplifier is connected to the inverting node and the non-inverting node. The first differential amplifier has an output node, and produces on the output node an output potential that defines an output signal having a magnitude that is a function of the magnitude of the difference between a first potential at the inverting node and a second potential at the non-inverting node. The second differential amplifier is also connected to the inverting node and the non-inverting node. The second differential amplifier produces a compensation signal. The operational amplifier further includes capacitive circuitry for coupling the compensation signal to the non-inverting node.
Inventors
- 👤 Timothy G. O'Shaughnessy
- 👤 Mike Spaur
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:59
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071; H03F3/45076; H03F3/45179; H03F1/00; H03F1/08; H03F1/083; H03F1/086; H03F3/45376; H03F3/45381; H03F3/45385; H03F2203/00; H03F2203/45; H03F2203/45458; H03F2203/45674; H03F2203/45676
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
142 words
A stability-compensated, integrated-circuit operational amplifier comprising: an inverting node and a non-inverting node; a first differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means of the first differential amplifier having an output node, and having means for producing on the output node an output potential that, with reference to a predetermined potential, defines an output signal having a magnitude that is a function of the magnitude of the difference between a first potential at the inverting node and a second potential at the non-inverting node; a second differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means for having means for producing a compensation signal; and capacitance means for coupling the compensation signal to the non-inverting node.
Claim 2
Dependent Claim
142 words
A stability-compensated, integrated-circuit operational amplifier comprising: an inverting node and a non-inverting node; a first differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means of the first differential amplifier having an output node, and having means for producing on the output node an output potential that, with reference to a predetermined potential, defines an output signal having a magnitude that is a function of the magnitude of the difference between a first potential at the inverting node and a second potential at the non-inverting node; a second differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means for having means for producing a compensation signal; and capacitance means for coupling the compensation signal to the non-inverting node.
Claim 3
Dependent Claim
37 words
A stability-compensated, integrated-circuit operational amplifier in accord with claim 1, wherein the first differential amplifier comprises a current-source biased differential input stage with cascoded differential legs and a current mirror active load also cascoded for increased gain.
Claim 4
Dependent Claim
28 words
A stability-compensated, integrated-circuit operational amplifier in accord with claim 2, wherein the second differential amplifier comprises a current-source biased differential input stage and a current mirror active load.
Claim 5
Dependent Claim
203 words
An integrated-circuit precision-current source comprising: an operational amplifier comprising: an inverting node to which a reference potential is applied; a non-inverting node to which a feedback potential is applied; a first differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means of the first differential amplifier having an output node, and having means for producing on the output node an output potential that, with reference to a predetermined potential, defines an output signal having a magnitude that is a function of the magnitude of the difference between the reference potential and the feedback potential; a second differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means for having means for producing a compensation signal; and capacitance means for coupling the compensation signal to the non-inverting node; resistance-loaded signal-inverting MOSFET means defining a first current flow path, and biased by the output potential for controlled current flow through the first flow path to produce the feedback potential; and signal-inverting MOSFET means biased by the output potential to produce a current in a second path in parallel with the first path.
Claim 6
Dependent Claim
203 words
An integrated-circuit precision-current source comprising: an operational amplifier comprising: an inverting node to which a reference potential is applied; a non-inverting node to which a feedback potential is applied; a first differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means of the first differential amplifier having an output node, and having means for producing on the output node an output potential that, with reference to a predetermined potential, defines an output signal having a magnitude that is a function of the magnitude of the difference between the reference potential and the feedback potential; a second differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means for having means for producing a compensation signal; and capacitance means for coupling the compensation signal to the non-inverting node; resistance-loaded signal-inverting MOSFET means defining a first current flow path, and biased by the output potential for controlled current flow through the first flow path to produce the feedback potential; and signal-inverting MOSFET means biased by the output potential to produce a current in a second path in parallel with the first path.
Claim 7
Dependent Claim
24 words
An integrated-circuit precision-current source in accord with claim 4, and further comprising CMOS circuit means for mirroring the current flowing in the second path.
Claim 8
Dependent Claim
23 words
An integrated-circuit precision-current source in accord with claim 4, wherein the signal-inverting MOSFET means comprise a plurality of MOSFETs positioned in an array.
Claim 9
Dependent Claim
217 words
An integrated-circuit precision-current source comprising: an operational amplifier comprising: a pair of nodes defining an inverting node and a non-inverting node, to one of which a reference potential is applied and to the other of which a feedback potential is applied; a first differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means of the first differential amplifier having an output node, and having means for producing on the output node an output potential that, with reference to a predetermined potential, defines an output signal having a magnitude that is a function of the magnitude of the difference between the reference and feedback potentials; a second differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means for having means for producing a compensation signal; and capacitance means for coupling the compensation signal to the node to which the feedback potential is applied; resistance-loaded MOSFET means defining a first current flow path, and biased by the output potential for controlled current flow through the first flow path to produce the feedback potential; and MOSFET means biased by the output potential to produce a current in a second path in parallel with the first path.
Claim 10
Dependent Claim
217 words
An integrated-circuit precision-current source comprising: an operational amplifier comprising: a pair of nodes defining an inverting node and a non-inverting node, to one of which a reference potential is applied and to the other of which a feedback potential is applied; a first differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means of the first differential amplifier having an output node, and having means for producing on the output node an output potential that, with reference to a predetermined potential, defines an output signal having a magnitude that is a function of the magnitude of the difference between the reference and feedback potentials; a second differential amplifier comprising CMOS transistor means that are connected to the inverting node and to the non-inverting node, the CMOS transistor means for having means for producing a compensation signal; and capacitance means for coupling the compensation signal to the node to which the feedback potential is applied; resistance-loaded MOSFET means defining a first current flow path, and biased by the output potential for controlled current flow through the first flow path to produce the feedback potential; and MOSFET means biased by the output potential to produce a current in a second path in parallel with the first path.
Claim 11
Dependent Claim
24 words
An integrated-circuit precision-current source in accord with claim 7, and further comprising CMOS circuit means for mirroring the current flowing in the second path.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-10 | 1994-12-10 | 1995-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-10 | 1998-12-10 | 1999-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-10 | 2002-12-10 | 2003-06-11 | $7700.00 | Window Closed / Lapsed |