Patent US3684973A successfully refreshed from Google Patents.
US3684973A
Expired / Lapsed
US
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Circuit arrangement for a difference amplifier in integrated construction
Assignee: Individual
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Filing: 1970-08-26
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Granted: 1972-08-15
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Expires: 1990-08-26
Abstract
Abstract A monolithically integrated difference amplifier having closely adjacent transistors of equal geometrical form and substantially equal properties such that the collector currents in said transistors are equal when said difference amplifier is in a quiescent state is described. The output impedances of the transistors forming the difference amplifier are active impedances, preferably transistors connected in a common base configuration and having their bases connected in common. Coupling between the bases of the active impedance output circuits and the difference amplifier is accomplished by means of an auxiliary difference amplifier.
Inventors
- 👤 Wolfgang Duck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:28
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
98 words
In a difference amplifier comprising a pair of transistors forming parallel current paths and having like properties so that the collector currents therethrough are equal when said amplifier is in a quiescent condition and wherein the collector impedance of each said transistor is an active impedance having a control electrode, said control electrodes being coupled in common to the collector of one of said pair of transistors, the improvement comprising: an auxiliary difference amplifier having an input connected to said collector of one of said pair of transistors and an output connected in common to said control electrodes.
Claim 2
Dependent Claim
98 words
In a difference amplifier comprising a pair of transistors forming parallel current paths and having like properties so that the collector currents therethrough are equal when said amplifier is in a quiescent condition and wherein the collector impedance of each said transistor is an active impedance having a control electrode, said control electrodes being coupled in common to the collector of one of said pair of transistors, the improvement comprising: an auxiliary difference amplifier having an input connected to said collector of one of said pair of transistors and an output connected in common to said control electrodes.
Claim 3
Dependent Claim
43 words
The improved difference amplifier defined in claim 1, wherein said active impedances are a second pair of transistors wherein the conduction paths therethrough, respectively, form parts of the collector circuits of said pair of transistors, and the bases thereof constitute said control electrodes.
Claim 4
Dependent Claim
25 words
The improved difference amplifier defined in claim 2, wherein said pair of transistors are NPN transistors and said second pair of transistors are PNP transistors.
Claim 5
Dependent Claim
73 words
The improved difference amplifier defined in claim 1, wherein said auxiliary difference amplifier comprises a third pair of transistors forming parallel current paths connected in such a manner that the collector of one of said third pair of transistors supplies current to said control electrodes and the base of the other of said third pair of transistors is connected to the collector of one of said pair of transistors forming said difference amplifier.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |