US3739293A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Monolithic integrated circuit operational amplifier
Assignee: AT&T Inc
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Filing: 1971-11-24
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Granted: 1973-06-12
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Expires: 1991-11-24
Abstract
Abstract A monolithic integrated circuit operational amplifier has a Darlington connected differential amplifier input stage. The emitters of the differential amplifier are connected to a negative current source and the collectors are connected through resistors to the emitters of first and second common base transistors. The resistor in the emitter of the second common base transistor has a cross-coupled amplifier circuit in parallel with it. The collector of the first common base transistor is connected to a positive voltage source and the collector of the second is connected to a positive current source which is locked to the negative current source. This collector is also connected to the output of the circuit through a Darlington amplifier, a voltage level shift circuit, and a common-emitter transistor.
Inventors
- 👤 V Saari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:03
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071; H03F3/45076; H03F3/4508; H03F3/45085; H03F3/45089; H03F1/00; H03F1/42; H03F1/48; H03F3/34; H03F3/343; H03F3/347; H03F3/45479; H03F2203/00; H03F2203/45; H03F2203/45318; H03F2203/45352; H03F2203/45374
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
238 words
A transistor amplifier circuit having an input and an output, comprising: an input common emitter differential amplifier stage having first and second output terminals, a first input connected to said circuit input and a second input connected to ground; a common base stage, comprising first and second transistors arranged in common base configuration with their bases connected to a first reference potential and the collector of the first transistor connected to a second reference potential; a first circuit resistance connected between the first output of said differential amplifier stage and the emitter of the first transistor of said common base stage; a second circuit resistance connected between the second output of said differential amplifier stage and the emitter of the second transistor of said common base stage; a current supply means for controlling a plurality of currents at a plurality of its outputs, a first output of said current supply means being connected to the common emitter connection of said differential amplifier stage and drawing a first current therefrom, a second output of said current supply means being connected to the collector of the second transistor of said common base stage and supplying a second current thereto, said first and second currents being locked together in a substantially constant ratio; and an output stage having its input connected to the collector of the second transistor of said common base stage and its output connected to said circuit output.
Claim 2
Dependent Claim
238 words
A transistor amplifier circuit having an input and an output, comprising: an input common emitter differential amplifier stage having first and second output terminals, a first input connected to said circuit input and a second input connected to ground; a common base stage, comprising first and second transistors arranged in common base configuration with their bases connected to a first reference potential and the collector of the first transistor connected to a second reference potential; a first circuit resistance connected between the first output of said differential amplifier stage and the emitter of the first transistor of said common base stage; a second circuit resistance connected between the second output of said differential amplifier stage and the emitter of the second transistor of said common base stage; a current supply means for controlling a plurality of currents at a plurality of its outputs, a first output of said current supply means being connected to the common emitter connection of said differential amplifier stage and drawing a first current therefrom, a second output of said current supply means being connected to the collector of the second transistor of said common base stage and supplying a second current thereto, said first and second currents being locked together in a substantially constant ratio; and an output stage having its input connected to the collector of the second transistor of said common base stage and its output connected to said circuit output.
Claim 3
Dependent Claim
223 words
An amplifier circuit as claimed in claim 1 wherein said input common emitter differential amplifier stage comprises: a first transistor pair comprising first and second differential transistors arranged in a Darlington configuration with the base of the first differential transistor connected to said circuit input, the collectors of both the first and second differential transistors connected to the first output of said differential amplifier stage, and the emitter of the first differential transistor connected to the base of the second differential transistor, a third output of said current supply means being connected to the emitter of the first differential transistor and drawing a third current therefrom; and a second transistor pair comprising third and fourth differential transistors arranged in a Darlington configuration with the base of the third differential transistor connected to ground, the collectors of both the third and fourth differential transistors connected to the second output of said differential amplifier stage, the emitter of the third differential transistor connected to the base of the fourth differential transistor, the emitter of the fourth differential transistor connected to the emitter of the second differential transistor and a fourth output of said current supply means connected to the emitter of said third differential transistor and drawing a fourth current therefrom, said first, second, third and fourth currents being locked in a substantially constant ratio.
Claim 4
Dependent Claim
154 words
An amplifier as claimed in claim 1 wherein said output stage comprises: a first output transistor having its collector connected to the output of said amplifier circuit and its emitter connected to a third reference potential; second and third output transistors arranged in a Darlington configuration with the base of said second output transistor connected to the input of said output stage, the collectors of said second and third output transistors connected to a fourth reference potential and the emitter of said second output transistor connected to the base of said third output transistor; a first output resistance connected between the base and emitter of said third output transistor; a voltage level shift circuit having its input connected to the emitter of said third output transistor and its output connected to the base of said first output transistor; and a second output resistance connected between the base and emitter of said first output transistor.
Claim 5
Dependent Claim
73 words
An amplifier circuit as claimed in claim 3 further including a first capacitor connected between said circuit input and the emitter of said second transistor of said common base stage; a second capacitor connected between the collector of said second transistor of said common base stage and the base of the first output transistor; and a third capacitor connected between the second output of said differential amplifier stage and a fifth reference potential.
Claim 6
Dependent Claim
19 words
An amplifier circuit as claimed in claim 1 further including a current amplifier in parallel with said second resistor.
Claim 7
Dependent Claim
139 words
An amplifier circuit as claimed in claim 5 wherein said current amplifier is a cross-coupled amplifier comprising: a first current amplifier transistor having its collector connected to the emitter of the second transistor of said common base stage and its base connected to a sixth reference potential; a second current amplifier transistor having its base connected to the second output of said input differential amplifier stage and its emitter connected to the emitter of said first current amplifier transistor; a first current amplifier resistor connected between the emitter of said second current amplifier transistor and a seventh reference potential; and a second current amplifier resistor connected between the collector of said second current amplifier transistor and the base of said first current amplifier transistor, said second current amplifier resistor having substantially the same resistance as said first circuit resistance.
Claim 8
Dependent Claim
119 words
An amplifier circuit as claimed in claim 5 wherein said current amplifier is a cross-coupled amplifier comprising: a first current amplifier transistor having its collector connected to the emitter of the second transistor of said common base stage and its base connected to the first output of said input differential amplifier stage; a second current amplifier transistor having its collector connected to the emitter of the first transistor of said common base stage, its base connected to the second output of said input differential ampLifier stage, and its emitter connected to the emitter of said first current amplifier transistor; and a first amplifier resistor connected between the emitter of said second current amplifier transistor and a eighth reference potential.
Claim 9
Dependent Claim
17 words
A circuit as claimed in claim 5 wherein said amplifier circuit is a monolithic semiconductor integrated amplifier.
Claim 10
Dependent Claim
42 words
A monolithic semiconductor integrated amplifier as claimed in claim 8, further including first and second feedback resistors arranged in series between the input and output of said circuit, thereby permitting testing of the amplifier without the addition of an external feedback resistor.
Claim 11
Dependent Claim
36 words
A monolithic semiconductor integrated amplifier as claimed in claim 8, further including a voltage regulating means for generating the various reference potentials required in the circuit from a single positive and a single negative power supply.
References Cited (Backward Citations)
US3408586A
Cited
US3569849A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |