US3573504A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature compensated current source
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1968-01-16
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Granted: 1971-04-06
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Expires: 1988-01-16
Abstract
Abstract A current source which is substantially independent of variations of temperature. Thus the current source may be made either to have a linear dependence upon changes of temperature or, by the simple addition of a resistor, may be made substantially independent of temperature variations. Since the current source consists only of transistors of one conductivity type and resistors, it is ideally suited for manufacture in the form of a monolithic integrated circuit. The invention described herein was made in the performance of work under a NASA contract and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958, Public Law 85-568.
Inventors
- 👤 David Roy Breuer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:06
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071; H03F3/45479; G; G05; G05F; G05F1/00; G05F1/10; G05F1/46; G05F1/56; G05F1/562; H03F1/00; H03F1/30; H03F1/302
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
195 words
A current source for providing an output current which is linearly dependent upon temperature variations, said source comprising: a. a first and a second transistor, said transistors being of the same conductivity type and having substantially equal alphas and betas; b. said first transistor having its base connected directly to the collector of said second transistor; c. said first transistor having its emitter connected directly to the base of said second transistor; d. a source of regulated voltage; e. a first resistor connected between one of the terminals of said voltage source and the collector of said second transistor; f. a second resistor connected between the junction point of the emitter of said first transistor and the base of said second transistor, and the other terminal of said voltage source, the emitter of said second transistor being coupled to said other terminal of said voltage source; and g. means isolated from said source and connected to the collector of said first transistor for deriving an output current, said output current being substantially a linear function of temperature provided the reciprocal value of the beta of each of said transistors is substantially negligible compared to one.
Claim 2
Dependent Claim
195 words
A current source for providing an output current which is linearly dependent upon temperature variations, said source comprising: a. a first and a second transistor, said transistors being of the same conductivity type and having substantially equal alphas and betas; b. said first transistor having its base connected directly to the collector of said second transistor; c. said first transistor having its emitter connected directly to the base of said second transistor; d. a source of regulated voltage; e. a first resistor connected between one of the terminals of said voltage source and the collector of said second transistor; f. a second resistor connected between the junction point of the emitter of said first transistor and the base of said second transistor, and the other terminal of said voltage source, the emitter of said second transistor being coupled to said other terminal of said voltage source; and g. means isolated from said source and connected to the collector of said first transistor for deriving an output current, said output current being substantially a linear function of temperature provided the reciprocal value of the beta of each of said transistors is substantially negligible compared to one.
Claim 3
Dependent Claim
25 words
A current source as defined in claim 1 wherein the magnitude of said output current is controllable by controlling the resistance of said second resistor.
Claim 4
Dependent Claim
227 words
A current source for providing an output current which is substantially independent of temperature variations, said source comprising: a. a first and a second transistor, said transistors being of the same conductivity type and having substantially equal alphas and betas; b. said first transistor having its base connected directly to the collector of said second transistor; c. said first transistor having its emitter connected directly to the base of said second transistor; d. a source of regulated voltage; e. a first resistor connected between one of the terminals of said voltage source and the collector of said second transistor; f. a second resistor connected between the junction point of the emitter of said first transistor and the base of said second transistor, and the other terminal of said voltage source, the emitter of said second transistor being coupLed to said other terminal of said voltage source; g. a third resistor connected between the emitter of said second transistor and the other terminal of said voltage source; and h. means isolated from said source and connected to the collector of said first transistor for deriving an output current, said output current being substantially independent of temperature provided that the reciprocal value of the beta of each of said transistors is substantially negligible compared to one, and that the resistance of said first and third resistors are substantially zero.
Claim 5
Dependent Claim
227 words
A current source for providing an output current which is substantially independent of temperature variations, said source comprising: a. a first and a second transistor, said transistors being of the same conductivity type and having substantially equal alphas and betas; b. said first transistor having its base connected directly to the collector of said second transistor; c. said first transistor having its emitter connected directly to the base of said second transistor; d. a source of regulated voltage; e. a first resistor connected between one of the terminals of said voltage source and the collector of said second transistor; f. a second resistor connected between the junction point of the emitter of said first transistor and the base of said second transistor, and the other terminal of said voltage source, the emitter of said second transistor being coupLed to said other terminal of said voltage source; g. a third resistor connected between the emitter of said second transistor and the other terminal of said voltage source; and h. means isolated from said source and connected to the collector of said first transistor for deriving an output current, said output current being substantially independent of temperature provided that the reciprocal value of the beta of each of said transistors is substantially negligible compared to one, and that the resistance of said first and third resistors are substantially zero.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-05 | 1974-10-05 | 1975-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-05 | 1978-10-05 | 1979-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-05 | 1982-10-05 | 1983-04-06 | $7700.00 | Window Closed / Lapsed |