Patent US5481220A successfully refreshed from Google Patents.
US5481220A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual matching current sink total temperature circuit
Assignee: Honeywell Inc
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Filing: 1995-04-13
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Granted: 1996-01-02
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Expires: 2015-04-13
Abstract
Abstract The disclosure relates to a calibration-free analog processing circuit for use with an outside total temperature probe and an air data computer. Dual matching transistors are used to sink the current. A reference buffer provides operating current to the matching transistors. The output of the dual transistors represents the resistance in the probe and thereby the outside temperature.
Inventors
- 👤 James W. Mildren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:29
CPC Classifications
G; G01; G01K; G01K7/00; G01K7/16; G01K7/18; G01K7/20
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
104 words
An analog monitoring circuit for use with a temperature sensitive resistance probe and an air data computer, said circuit comprising: reference buffer means for creating adequate operating current in response to input from a reference voltage source operable at a selected voltage; matching dual current means operatively connected to said reference buffer means through ratio-metric voltage divider means, said matching dual current means is also connected to the probe and provides an output representative of the resistance of the probe and thereby the temperature of the probe; and differential amplifier means operatively connected to the matching dual current means for developing a desired gain.
Claim 2
Dependent Claim
104 words
An analog monitoring circuit for use with a temperature sensitive resistance probe and an air data computer, said circuit comprising: reference buffer means for creating adequate operating current in response to input from a reference voltage source operable at a selected voltage; matching dual current means operatively connected to said reference buffer means through ratio-metric voltage divider means, said matching dual current means is also connected to the probe and provides an output representative of the resistance of the probe and thereby the temperature of the probe; and differential amplifier means operatively connected to the matching dual current means for developing a desired gain.
Claim 3
Dependent Claim
17 words
The invention of claim 1 further comprising voltage invertor means operatively connected to said differential amplifier means.
Claim 4
Dependent Claim
20 words
The invention of claim 2 wherein said voltage invertor means connects to said differential amplifier means through ratio-metric resistance means.
Claim 5
Dependent Claim
15 words
The invention of claim 3 wherein said voltage invertor means comprises ratio-metric resistance feedback means.
Claim 6
Dependent Claim
51 words
The invention of claim 1 wherein said matching dual current means comprises a matching pair of transistors, each transistor having a base, an emitter and a collector, and an operational amplifier operatively connected to the base of each of the transistors and in a feedback loop with one of the transistors.
Claim 7
Dependent Claim
23 words
The invention of claim 5 wherein the emitters of said transistors are operatively connected to said reference buffer means through matched precision resistors.
Claim 8
Dependent Claim
25 words
The invention of claim 5 wherein the collectors of said transistors connect to the probe through a precision resistor tailored to the particular probe used.
Claim 9
Dependent Claim
23 words
The invention of claim 1 wherein said differential amplifier means connects to output of said matching dual current means through ratio-metric resistance elements.
Claim 10
Dependent Claim
15 words
The invention of claim 8 wherein said differential amplifier means comprises ratio-metric resistor feedback means.
Claim 11
Dependent Claim
128 words
An analog monitoring circuit for use with a temperature sensitive resistance probe and an air data computer, said circuit comprising: reference buffer means for creating adequate operating current in response to input from a reference voltage source operable at a selected voltage; matching dual current means comprised of a matching pair of transistors and an operational amplifier operatively connected to a base of each of the transistors and in a feedback loop with one of the transistors, said matching dual current means is operatively connected to said reference buffer means and the probe for producing an output representative of the resistance of the probe and thereby the temperature of the probe; and differential amplifier means operatively connected to the matching dual current means for developing a desired gain.
Claim 12
Dependent Claim
128 words
An analog monitoring circuit for use with a temperature sensitive resistance probe and an air data computer, said circuit comprising: reference buffer means for creating adequate operating current in response to input from a reference voltage source operable at a selected voltage; matching dual current means comprised of a matching pair of transistors and an operational amplifier operatively connected to a base of each of the transistors and in a feedback loop with one of the transistors, said matching dual current means is operatively connected to said reference buffer means and the probe for producing an output representative of the resistance of the probe and thereby the temperature of the probe; and differential amplifier means operatively connected to the matching dual current means for developing a desired gain.
Claim 13
Dependent Claim
17 words
The invention of claim 10 further comprising voltage invertor means operatively connected to said differential amplifier means.
Claim 14
Dependent Claim
20 words
The invention of claim 11 wherein said voltage invertor means connects to said differential amplifier means through ratio-metric resistance means.
Claim 15
Dependent Claim
15 words
The invention of claim 12 wherein said voltage invertor means comprises ratio-metric resistance feedback means.
Claim 16
Dependent Claim
22 words
The invention of claim 10 wherein emitters of said transistors are operatively connected to said reference buffer means through matched precision resistors.
Claim 17
Dependent Claim
24 words
The invention of claim 10 wherein collectors of said transistors connect to the probe through a precision resistor tailored to the particular probe used.
Claim 18
Dependent Claim
24 words
The invention of claim 10 wherein said differential amplifier means connects to an output of said matching dual current means through ratio-metric resistance elements.
Claim 19
Dependent Claim
22 words
The invention of claim 10 wherein said differential amplifier means comprises ratio-metric resistor feedback mean coupled to said matching dual current means.
Claim 20
Dependent Claim
22 words
The invention of claim 10 wherein said reference buffer means connects to said matching dual current means through ratio-metric voltage divider means.
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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) | 1999-01-01 | 1999-07-03 | 2000-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-01 | 2003-07-03 | 2004-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-01 | 2007-07-03 | 2008-01-02 | $7700.00 | Window Closed / Lapsed |