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US4468628A
Expired / Lapsed
US
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Differential amplifier with high common-mode rejection
Assignee: Micron Technology Inc
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Filing: 1983-01-17
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Granted: 1984-08-28
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Expires: 2003-01-17
Abstract
Abstract A differential shunt feedback amplifier includes dual shunt feedback paths, with an emitter follower in each feedback path to provide a low impedance output with a well-defined gain. A common-mode current generator responsive to only the common-mode component of an input signal generates a current which offsets base current changes in the emitter followers caused by the common-mode component. The circuit is well suited for either push-pull or single-ended input operation over a wide range of frequencies.
Inventors
- 👤 Winthrop A. Gross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:16
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071; H03F3/45479
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
154 words
A differential amplifier, comprising: an input signal path; a first and second transistor for receiving said input signal, the emitters of which are coupled together in common; a constant current generator connected to the common emitters of said first and second transistors; a first and a second shunt feedback path, said first shunt feedback path including a third transistor arranged as an emitter follower connected between the collector and base of said first transistor and said second shunt feedback path including a fourth transistor arranged as an emitter follower connected between the collector and base of said second transistor; first and second output terminals coupled to the emitters of said third and fourth transistors, respectively; and means coupled to the common emitters of said first and second transistors to generate a current change to offset the base current change of said third and fourth transistors in response to common-mode components of said input signal.
Claim 2
Dependent Claim
154 words
A differential amplifier, comprising: an input signal path; a first and second transistor for receiving said input signal, the emitters of which are coupled together in common; a constant current generator connected to the common emitters of said first and second transistors; a first and a second shunt feedback path, said first shunt feedback path including a third transistor arranged as an emitter follower connected between the collector and base of said first transistor and said second shunt feedback path including a fourth transistor arranged as an emitter follower connected between the collector and base of said second transistor; first and second output terminals coupled to the emitters of said third and fourth transistors, respectively; and means coupled to the common emitters of said first and second transistors to generate a current change to offset the base current change of said third and fourth transistors in response to common-mode components of said input signal.
Claim 3
Dependent Claim
27 words
A differential amplifier in accordance with claim 1 wherein said current-change generating means comprises impedance means across which said common-mode components of said input signal are developed.
Claim 4
Dependent Claim
46 words
A differential amplifier in accordance with claim 2 wherein the value of said impedance means is equal to 1/2(β+1)R f , wherein βis the beta of one of said third and fourth transistors, and R f is the impedance in one of said shunt feedback paths.
Claim 5
Dependent Claim
15 words
A differential amplifier in accordance with claim 3 wherein said impedance means comprises a resistor.
Claim 6
Dependent Claim
44 words
A differential amplifier in accordance with claim 3 wherein said impedance means comprises a fifth transistor, the base of which is connected to the common emitters of said first and second transistors, and the emitter of which is connected to at least a resistor.
References Cited (Backward Citations)
US4232271A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-28 | 1988-02-27 | 1988-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-28 | 1992-02-27 | 1992-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-28 | 1996-02-27 | 1996-08-28 | $7700.00 | Window Closed / Lapsed |