Patent US6402750B1 successfully refreshed from Google Patents.
US3668541A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current compensator circuit
Assignee: Teledyne Inc
•
Filing: 1970-03-23
•
Granted: 1972-06-06
•
Expires: 1990-03-23
Abstract
Abstract A current compensating circuit for compensating a transistor for thermal variations in its operating point. The circuit includes a compensating transistor of the same conductivity type as the transistor to be compensated, the two transistors being thermally matched to one another. The compensating transistor is connected so that it is supplied with a constant electric current and its emitter is direct coupled to the emitter of the transistor to be compensated. A compensating current is provided by a pair of transistors thermally matched to one another and of opposite conductivity type to the first transistors. One of the second pair has its collector connected to the base of the compensating transistor while the other of the second pair has its collector connected to the base of the transistor to be compensated. The current generating transistors have their bases connected to one another and their emitters connected to one another and to the collector of the compensating transistor. The principles are also applicable to a more complex circuit such as a differential amplifier wherein each of the input transistors of the differential amplifier are provided with transistors which provide a thermally variable correction current to the respective bases of the input transistors.
Inventors
- 👤 Robert A Pease
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:21
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/56
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
130 words
In apparatus for providing compensation of thermally caused variations in the operation of a first transistor adapted to have input signals applied to the base thereof, and including a compensating transistor of the same conductivity type as said first transistor and having thermally variable characteristics substantially matched to the thermally variable characteristics of said first transistor, the emitter-collector circuit of said compensating transistor being connected, to the emitter-collector circuit of said first transistor, means for providing substantially identical currents to said connected emittercollector circuits, and means for thermally linking said transistors, said apparatus comprising in combination: transistor means responsive to the base current flowing in said compensating transistor for generating a temperature compensating current and being connected for introducing said temperature compensating current into said base of said first transistor.
Claim 2
Dependent Claim
130 words
In apparatus for providing compensation of thermally caused variations in the operation of a first transistor adapted to have input signals applied to the base thereof, and including a compensating transistor of the same conductivity type as said first transistor and having thermally variable characteristics substantially matched to the thermally variable characteristics of said first transistor, the emitter-collector circuit of said compensating transistor being connected, to the emitter-collector circuit of said first transistor, means for providing substantially identical currents to said connected emittercollector circuits, and means for thermally linking said transistors, said apparatus comprising in combination: transistor means responsive to the base current flowing in said compensating transistor for generating a temperature compensating current and being connected for introducing said temperature compensating current into said base of said first transistor.
Claim 3
Dependent Claim
97 words
Apparatus as defined in claim 1 wherein said transistor means comprises third and fourth transistors of opposite conductivity type to said compensating transistor, said third transistor having its collector and emitter respectively connected to the base and collector of said compensating transistor, said fourth transistor having its base and emitter respectively connected to the base and emitter of said third transistor, resistive means connecting the bases of said third and fourth transistors to the emitters of the first and compensating transistors, and means connecting the collector of said fourth transistor to the base of said first transistor.
Claim 4
Dependent Claim
47 words
Apparatus as defined in claim 2 wherein said resistive means is comprised of diode means connected between the base of said third transistor and the emitters of said first and compensating transistor, and poled normally for forward biasing the third and fourth transistors into a conducting state.
Claim 5
Dependent Claim
219 words
Apparatus for providing compensation of at least a pair of transistors in differential amplifier configuration wherein said pair of transistors have mutually matched thermally variable characteristics and are of like conductivity type, said apparatus also including a compensating transistor of the same conductivity type as said pair of transistors and having thermally variable characteristics matched to track the thermally variable characteristics of said pair of transistors, and a first substantially constant current source connected to the collector of said compensating transistor, the emitters of all of said transistors being coupled to one another and to a second substantially constant current source, in combination fourth, fifth, and sixth transistors of the same conductivity type as one another and of opposite conductivity type to said compensating transistor, all of the bases of said fourth, fifth, and sixth transistors being connected to one another and connected by resistive means to the emitters of said first pair of transistors and said compensating transistors, and all of the emitters of said fourth, fifth, and sixth transistors being connected to one another and to the collector of said compensating transistor, the collector of said fourth transistor being connected to the base of said compensating transistor and the collectors of said fifth and sixth transistors being respectively Connected to the bases of said pair of transistors.
Claim 6
Dependent Claim
219 words
Apparatus for providing compensation of at least a pair of transistors in differential amplifier configuration wherein said pair of transistors have mutually matched thermally variable characteristics and are of like conductivity type, said apparatus also including a compensating transistor of the same conductivity type as said pair of transistors and having thermally variable characteristics matched to track the thermally variable characteristics of said pair of transistors, and a first substantially constant current source connected to the collector of said compensating transistor, the emitters of all of said transistors being coupled to one another and to a second substantially constant current source, in combination fourth, fifth, and sixth transistors of the same conductivity type as one another and of opposite conductivity type to said compensating transistor, all of the bases of said fourth, fifth, and sixth transistors being connected to one another and connected by resistive means to the emitters of said first pair of transistors and said compensating transistors, and all of the emitters of said fourth, fifth, and sixth transistors being connected to one another and to the collector of said compensating transistor, the collector of said fourth transistor being connected to the base of said compensating transistor and the collectors of said fifth and sixth transistors being respectively Connected to the bases of said pair of transistors.
Claim 7
Dependent Claim
50 words
Apparatus as defined in claim 4 wherein said resistive means is comprised of diode means connected between the coupled emitters of said pair of transistors and the connected bases of said fourth, fifth, and sixth transistors, and being poled for normally biasing said fourth, fifth, and sixth transistors into conduction.
Claim 8
Dependent Claim
51 words
Apparatus as defined in claim 2 further including mans for providing a substantially constant current to the emitters of said first and compensating transistors to insure equal bias and operating conditions, said constant current being approximately twice the amplitude of the constant current applied to the collector of said compensating transistor.
Claim 9
Dependent Claim
51 words
Apparatus as defined in claim 4 wherein the constant current provided by said second current source is of approximately three times the amplitude as the current provided by said first current source to insure equal bias and operating conditions for each of said first pair of transistors and said compensating transistor.
Claim 10
Dependent Claim
18 words
Apparatus as defined in claim 2 wherein both said first and compensating transistors are Darlington connection composite transistors.
Claim 11
Dependent Claim
21 words
Apparatus as defined in claim 4 wherein said first pair of transistors and said compensating transistor are Darlington connection composite transistors.
References Cited (Backward Citations)
US3230468A
Cited
US3457519A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |