Patent FR2152284A5 successfully refreshed from Google Patents.
US5402064A
Expired / Lapsed
US
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Magnetoresistive sensor circuit with high output voltage swing and temperature compensation
Assignee: Raytheon Co
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Filing: 1992-09-02
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Granted: 1995-03-28
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Expires: 2012-09-02
Abstract
Abstract A magnetoresistor (MR) and a non-magnetoresistor (NMR) are formed of indium antimonide or other magnetoresistive material in thermal proximity to each other on an integrated circuit substrate (100). Hall effect shorting strips (104) are formed on the magnetoresistor (MR) to make it much more magnetoresistive than the non-magnetoresistor (NMR). A current mirror (80) causes equal constant currents (I2) which do not vary with temperature to flow through the magnetoresistor (MR) and non-magnetoresistor (NMR), such that magnetoresistor and non-magnetoresistor voltages are developed thereacross respectively. The magnetoresistor and non-magnetoresistor voltages vary equally in accordance with temperature. The magnetoresistor voltage also varies in accordance with applied magnetic flux. A comparator (66) subtracts the non-magnetoresistor voltage from the magnetoresistor voltage to produce an output signal (Vout) with the temperature variation canceled, and which thereby varies only in accordance with magnetic flux. The current mirror (80) has an essentially infinite equivalent load impedance, such that the magnetoresistor voltage varies to a maximum possible extent with variation of the resistance of the magnetoresistor (MR) and the sensor (70) has a maximum possible output voltage swing.
Inventors
- 👤 Robert E. Eck
- 👤 Paul T. Bryant
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:03
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/06; G01R33/09
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
98 words
A magnetoresistive sensor circuit, comprising: a magnetoresistor having a resistance which varies with an applied magnetic flux; a non-magnetoresistor which is disposed in thermal proximity to the magnetoresistor and has a resistance which is substantially unaffected by said magnetic flux; said resistances of the magnetoresistor and non-magnetoresistor varying substantially identically with temperature; a non-resistive constant current source means for causing substantially equal and constant currents to flow through the magnetoresistor and non-magnetoresistor to develop mangetoresistor and non-magnetoresistor voltages thereacross respectively; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 2
Dependent Claim
98 words
A magnetoresistive sensor circuit, comprising: a magnetoresistor having a resistance which varies with an applied magnetic flux; a non-magnetoresistor which is disposed in thermal proximity to the magnetoresistor and has a resistance which is substantially unaffected by said magnetic flux; said resistances of the magnetoresistor and non-magnetoresistor varying substantially identically with temperature; a non-resistive constant current source means for causing substantially equal and constant currents to flow through the magnetoresistor and non-magnetoresistor to develop mangetoresistor and non-magnetoresistor voltages thereacross respectively; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 3
Dependent Claim
108 words
A magnetoresistive sensor circuit, comprising: a magnetoresistor having a resistance which varies with an applied magnetic flux; a non-magnetoresistor which is disposed in thermal proximity to the magnetoresistor and has a resistance which is substantially unaffected by said magnetic flux; said resistances of the magnetoresistor and non-magnetoresistor varying substantially identically with temperature; constant current source means for causing substantially equal and constant currents to flow through the magnetoresistor and non-magnetoresistor to develop mangetoresistor and non-magnetoresistor voltages thereacross respectively in which the constant current source means comprises a current mirror means; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 4
Dependent Claim
108 words
A magnetoresistive sensor circuit, comprising: a magnetoresistor having a resistance which varies with an applied magnetic flux; a non-magnetoresistor which is disposed in thermal proximity to the magnetoresistor and has a resistance which is substantially unaffected by said magnetic flux; said resistances of the magnetoresistor and non-magnetoresistor varying substantially identically with temperature; constant current source means for causing substantially equal and constant currents to flow through the magnetoresistor and non-magnetoresistor to develop mangetoresistor and non-magnetoresistor voltages thereacross respectively in which the constant current source means comprises a current mirror means; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 5
Dependent Claim
178 words
A magnetoresistive sensor circuit, comprising: a magnetoresistor having a resistance which varies with an applied magnetic flux; a non-magnetoresistor which is disposed in thermal proximity to the magnetoresistor and has a resistance which is substantially unaffected by said magnetic flux; said resistances of the magnetoresistor and non-magnetoresistor varying substantially identically with temperature; constant current source means for causing substantially equal and constant currents to flow through the magnetoresistor and non-magnetoresistor to develop mangetoresistor and non-magnetoresistor voltages thereacross respectively in which the constant current source means comprises: voltage source means; a first transistor having a first controlled current path connected in series with the magnetoresistor across the voltage source means, and a first current control terminal; a second transistor having a second controlled current path connected in series with the non-magnetoresistor across the voltage source means, and a second current control terminal; and reference voltage source means for applying a predetermined reference voltage to said first and second current control terminals; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 6
Dependent Claim
178 words
A magnetoresistive sensor circuit, comprising: a magnetoresistor having a resistance which varies with an applied magnetic flux; a non-magnetoresistor which is disposed in thermal proximity to the magnetoresistor and has a resistance which is substantially unaffected by said magnetic flux; said resistances of the magnetoresistor and non-magnetoresistor varying substantially identically with temperature; constant current source means for causing substantially equal and constant currents to flow through the magnetoresistor and non-magnetoresistor to develop mangetoresistor and non-magnetoresistor voltages thereacross respectively in which the constant current source means comprises: voltage source means; a first transistor having a first controlled current path connected in series with the magnetoresistor across the voltage source means, and a first current control terminal; a second transistor having a second controlled current path connected in series with the non-magnetoresistor across the voltage source means, and a second current control terminal; and reference voltage source means for applying a predetermined reference voltage to said first and second current control terminals; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 7
Dependent Claim
56 words
A circuit as in claim 3, in which the reference voltage source means comprises: a fixed resistor; a diode-connected third transistor having a third controlled current path connected in series with the fixed resistor across the voltage source means, and a third current control terminal connected in circuit to said first and second current control terminals.
Claim 8
Dependent Claim
47 words
A circuit as in claim 4, in which: the first, second and third transistors are field-effect transistors; each of said first, second and third controlled current paths comprises a source and a drain; and each of said first, second and third current control terminals comprises a gate.
Claim 9
Dependent Claim
19 words
A circuit as in claim 4, in which the fixed resistor is thermally isolated from the magnetoresistor and non-magnetoresistor.
Claim 10
Dependent Claim
30 words
A circuit as in claim 1, in which the computing means comprises comparator means for producing said output signal in accordance with the difference between said magnetoresistor and non-magnetoresistor voltages.
Claim 11
Dependent Claim
110 words
A magnetoresistive integrated circuit sensor, comprising: a substrate; a magnetoresistor which is formed on the substrate and has a resistance which varies with temperature and also with an applied magnetic flux; a non-magnetoresistor which is formed on the substrate in thermal proximity to the magnetoresistor and has a resistance which varies with temperature and is substantially unaffected by said magnetic flux; a non-resistive constant current source means for causing constant currents to flow through the magnetoresistor and non-magnetoresistor to develop magnetoresistor an non-magnetoresistor voltages thereacross respectively which vary substantially equally with temperature; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 12
Dependent Claim
110 words
A magnetoresistive integrated circuit sensor, comprising: a substrate; a magnetoresistor which is formed on the substrate and has a resistance which varies with temperature and also with an applied magnetic flux; a non-magnetoresistor which is formed on the substrate in thermal proximity to the magnetoresistor and has a resistance which varies with temperature and is substantially unaffected by said magnetic flux; a non-resistive constant current source means for causing constant currents to flow through the magnetoresistor and non-magnetoresistor to develop magnetoresistor an non-magnetoresistor voltages thereacross respectively which vary substantially equally with temperature; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 13
Dependent Claim
120 words
A magnetoresistive integrated circuit sensor, comprising: a substrate; a magnetoresistor which is formed on the substrate and has a resistance which varies with temperature and also with an applied magnetic flux; a non-magnetoresistor which is formed on the substrate in thermal proximity to the magnetoresistor and has a resistance which varies with temperature and is substantially unaffected by said magnetic flux; constant current source means for causing constant currents to flow through the magnetoresistor and non-magnetoresistor to develop magnetoresistor an non-magnetoresistor voltages thereacross respectively which vary substantially equally with temperature in which the constant current source means comprises a current mirror means; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 14
Dependent Claim
120 words
A magnetoresistive integrated circuit sensor, comprising: a substrate; a magnetoresistor which is formed on the substrate and has a resistance which varies with temperature and also with an applied magnetic flux; a non-magnetoresistor which is formed on the substrate in thermal proximity to the magnetoresistor and has a resistance which varies with temperature and is substantially unaffected by said magnetic flux; constant current source means for causing constant currents to flow through the magnetoresistor and non-magnetoresistor to develop magnetoresistor an non-magnetoresistor voltages thereacross respectively which vary substantially equally with temperature in which the constant current source means comprises a current mirror means; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 15
Dependent Claim
202 words
A magnetoresistive integrated circuit sensor, comprising; a substrate; a magnetoresistor which is formed on the substrate and has a resistance which varies with temperature and also with an applied magnetic flux; a non-magnetoresistor which is formed on the substrate in thermal proximity to the magnetoresistor and has a resistance which varies with temperature and is substantially unaffected by said magnetic flux; constant current source means for causing constant currents to flow through the magnetoresistor and non-magnetoresistor to develop magnetoresistor an non-magnetoresistor voltages thereacross respectively which vary substantially equally with temperature in which the constant current source means comprises: voltage source means; a first transistor which is formed on the substrate and has a controlled current path connected in series with the magnetoresistor across the voltage source means, and a first current control terminal; a second transistor which is formed on the substrate and has a controlled current path connected in series with the non-magnetoresistor across the voltage source means, and a second current control terminal; and reference voltage source means for applying a predetermined reference voltage to said first and second current control terminals; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 16
Dependent Claim
202 words
A magnetoresistive integrated circuit sensor, comprising; a substrate; a magnetoresistor which is formed on the substrate and has a resistance which varies with temperature and also with an applied magnetic flux; a non-magnetoresistor which is formed on the substrate in thermal proximity to the magnetoresistor and has a resistance which varies with temperature and is substantially unaffected by said magnetic flux; constant current source means for causing constant currents to flow through the magnetoresistor and non-magnetoresistor to develop magnetoresistor an non-magnetoresistor voltages thereacross respectively which vary substantially equally with temperature in which the constant current source means comprises: voltage source means; a first transistor which is formed on the substrate and has a controlled current path connected in series with the magnetoresistor across the voltage source means, and a first current control terminal; a second transistor which is formed on the substrate and has a controlled current path connected in series with the non-magnetoresistor across the voltage source means, and a second current control terminal; and reference voltage source means for applying a predetermined reference voltage to said first and second current control terminals; and computing means for producing an output signal as a predetermined function of said magnetoresistor and non-magnetoresistor voltages.
Claim 17
Dependent Claim
62 words
A sensor as in claim 10, in which the reference voltage source means comprises: a fixed resistor; a diode-connected third transistor which is formed on the substrate and has a controlled current path connected in series with the fixed resistor across the voltage source means, and a third current control terminal connected in circuit to said first and second current control terminals.
Claim 18
Dependent Claim
47 words
A sensor as in claim 11, in which: the first, second and third transistors are field-effect transistors; each of said first, second and third controlled current paths comprises a source and a drain; and each of said first, second and third current control terminals comprises a gate.
Claim 19
Dependent Claim
19 words
A sensor as in claim 12, in which the fixed resistor is thermally isolated from the magnetoresistor and non-magnetoresistor.
Claim 20
Dependent Claim
17 words
A sensor as in claim 13, in which the fixed resistor is disposed external of the substrate.
Claim 21
Dependent Claim
30 words
A sensor as in claim 8, in which the computing means comprises comparator means for producing said output signal in accordance with the difference between said magnetoresistor and non-magnetoresistor voltages.
Claim 22
Dependent Claim
37 words
A sensor as in claim 8, in which: the magnetoresistor and non-magnetoresistor are formed of a magnetoresistive material; and the magnetoresistor further comprises a structure which causes the magnetoresistor to have much greater magnetoresistance than the non-magnetoresistor.
Claim 23
Dependent Claim
27 words
A sensor as in claim 16, in which said magnetoresistive material is selected from the group consisting of indium antimonide, indium arsenide, indium phosphide and gallium arsenide.
Claim 24
Dependent Claim
20 words
A sensor as in claim 16, in which: the substrate comprises gallium arsenide; and said magnetoresistive material comprises indium antimonide.
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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) | 1998-03-27 | 1998-09-26 | 1999-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-03-27 | 2002-09-26 | 2003-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-03-27 | 2006-09-26 | 2007-03-28 | $7700.00 | Window Closed / Lapsed |