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US3626313A
Expired / Lapsed
US
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Class ab amplifier for monolithic integrated circuit
Assignee: AT&T Inc
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Filing: 1970-03-10
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Granted: 1971-12-07
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Expires: 1990-03-10
Abstract
Abstract A transistor amplifier circuit for class AB operation having a low current in the quiescent state but high in the amplifying state as determined by the difference in emitter areas of two of the three transistors and the magnitude of a control resistor. The current amplification thus is independent of the beta of the transistors and all transistors are of the same conductivity type. The input branch contains a control transistor having a large area emitter connected through a control resistor to a common terminal. Also connected to the common terminal is the proportionately smaller area emitter of a current gain transistor whose collector in turn is connected to the emitter of a voltage amplitude control transistor likewise in the output branch. The bases of the control and current gain transistors are directly interconnected and bypass connection short circuits the basecollector PN junction of the current gain transistor.
Inventors
- 👤 Paul Zuk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:53
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/20; H03F3/21; H03F3/213
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
129 words
A transistor amplifier circuit for class AB operation including three transistors of the same conductivity type, said circuit comprising an input branch and an output branch interconnected at a common terminal for applying a voltage, said input branch including a control transistor and a control resistor, said control resistor being between said control transistor and said common terminal, the output branch including a current gain transistor and a voltage amplitude control transistor, the base electrode of the current gain transistor being directly connected to the base of the control transistor, a bypass connection from the base electrode to the collector electrode of the current gain transistor, and the emitter area of the control transistor being larger than the emitter area of the current gain transistor by a factor m.
Claim 2
Dependent Claim
129 words
A transistor amplifier circuit for class AB operation including three transistors of the same conductivity type, said circuit comprising an input branch and an output branch interconnected at a common terminal for applying a voltage, said input branch including a control transistor and a control resistor, said control resistor being between said control transistor and said common terminal, the output branch including a current gain transistor and a voltage amplitude control transistor, the base electrode of the current gain transistor being directly connected to the base of the control transistor, a bypass connection from the base electrode to the collector electrode of the current gain transistor, and the emitter area of the control transistor being larger than the emitter area of the current gain transistor by a factor m.
Claim 3
Dependent Claim
56 words
The transistor amplifier circuit in accordance with claim 1 in which the output branch includes in order from an output terminal the collector electrode of the voltage amplitude control transistor, the emitter electrode of the voltage amplitude control transistor, the collector electrode of the current gain transistor, and the emitter electrode of the current gain transistor.
Claim 4
Dependent Claim
91 words
The transistor amplifier circuit in accordance with claim 1 in which the input branch includes in order from an input terminal, an input series resistor, the collector electrode of the control transistor, the emitter electrode of the control transistor and the control resistor, and in which the output branch includes in order from an output terminal the collector electrode of the voltage amplitude control transistor, the emitter electrode of the voltage amplitude control transistor, the collector electrode of the current gain transistor, and the emitter electrode of the current gain transistor.
Claim 5
Dependent Claim
42 words
The transistor amplifier circuit in accordance with claim 4 in which the base electrode of the voltage amplitude control transistor is connected to the input branch at a point between the input series resistor and the collector electrode of the control transistor.
Claim 6
Dependent Claim
43 words
The transistor amplifier circuit in accordance with claim 5 in which the transistors are of the NPN-type, and the input and output terminals are adapted for application of a positive voltage and the common terminal is adapted for application of a negative voltage.
References Cited (Backward Citations)
US3418592A
Cited
US3531730A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |