US4625128A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated circuit temperature sensor
Assignee: AG Communication Systems Corp
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Filing: 1985-09-23
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Granted: 1986-11-25
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Expires: 2005-09-23
Abstract
Abstract An electrical circuit functioning as a temperature sensor which is fully compatible with silicon chip and similar integrated circuit technology. Four matched NPN bi-polar transistors provide a circuit that detects changes in temperature by monitoring the current throughput in operation. Environmental temperatures increase current approximately one order of magnitude for each 25 degrees centigrade of changing temperature. With a current gain of 100 for each transistor employed, the current increases from 0.1 microamp at 0 degrees centigrade to 11 microamps at 50 degrees centigrade.
Inventors
- 👤 Eduard F. B. Boeckmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:47
CPC Classifications
G; G01; G01K; G01K7/00; G01K7/01; H; H03; H03K; H03K17/00; H03K17/94
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
126 words
A circuit for sensing environmental temperature changes comprising: first, second, third and fourth transistors, each including base, emitter and collector electrodes; a source of reference voltage including positive and common output terminals; said first transistor emitter, said second transistor base and said fourth transistor base all connected to said reference voltage positive terminal; the collectors of said first, second and fourth transistors all connected together; said first transistor base and said second transistor emitter both connected to said third transistor collector; said fourth transistor emitter connected to said third transistor base; and said third transistor emitter connected to said reference voltage common terminal; said circuit operated in response to environmental temperature changes to vary the current flow through said third transistor proportionate to said temperature changes.
Claim 2
Dependent Claim
126 words
A circuit for sensing environmental temperature changes comprising: first, second, third and fourth transistors, each including base, emitter and collector electrodes; a source of reference voltage including positive and common output terminals; said first transistor emitter, said second transistor base and said fourth transistor base all connected to said reference voltage positive terminal; the collectors of said first, second and fourth transistors all connected together; said first transistor base and said second transistor emitter both connected to said third transistor collector; said fourth transistor emitter connected to said third transistor base; and said third transistor emitter connected to said reference voltage common terminal; said circuit operated in response to environmental temperature changes to vary the current flow through said third transistor proportionate to said temperature changes.
Claim 3
Dependent Claim
27 words
A circuit for sensing environmental temperature changes as claimed in claim 1, wherein: said first, second, third and fourth transistors are all of the NPN bi-polar type.
Claim 4
Dependent Claim
24 words
A circuit for sensing environmental temperature changes as claimed in claim 1, wherein: said first, second, third and fourth transistors all have matched characteristics.
Claim 5
Dependent Claim
25 words
A circuit for sensing environmental temperature changes as claimed in claim 1, wherein: all of said transistors are part of a common integrated circuit unit.
Claim 6
Dependent Claim
27 words
A circuit for sensing environmental temperature changes as claimed in claim 1, wherein: said source of reference voltage has an output voltage between 0.9 and 1.1 volts.
Claim 7
Dependent Claim
25 words
A circuit for sensing environmental temperature changes as claimed in claim 1, wherein: each of said transistors has a current gain between 90 and 110.
Claim 8
Dependent Claim
34 words
A circuit for sensing environmental temperature changes as claimed in claim 6, wherein: current flowing through said third transistor increases from 0.1 microamperes at 0 degrees Centigrade to 11 microamperes at 50 degrees centigrade.
References Cited (Backward Citations)
US3641372A
Cited
US3899695A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-11-24 | 1990-05-26 | 1990-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-24 | 1994-05-26 | 1994-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-24 | 1998-05-26 | 1998-11-25 | $7700.00 | Window Closed / Lapsed |