SENSOR TEMPERATURE COMPENSATION

• US 20080297955A1
• Filed: 05/30/2007
• Published: 12/04/2008
• Est. Priority Date: 05/30/2007
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Ausserlechner, Udo
• Granted Patent: US 7,825,656 B2
• Time in Patent Office: Days
• US Class Current: 360/326
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00

Abstract

A device includes a pair of individual sensors spaced apart from each other. A current source provides current to both of the individual sensors. A differential temperature sensor is coupled thermally proximate the individual sensors and provides a temperature difference signal that is combined with current from the current source to provide a correction factor for a temperature gradient across the individual sensors. Alternatively, temperature responsive excitation sources may be positioned thermally proximate the sensors to provide temperature compensation.

Claims

1. A device comprising:

first and second individual sensors spaced apart from each other;

a current source configured to provide current to each of the first and second individual sensors; and

a differential temperature sensor disposed thermally proximate the first and second individual sensors and configured to provide a temperature difference signal that can be combined with current from the current source to provide a correction factor for a temperature gradient across the first and second individual sensors.

2. The device of claim 1 wherein the correction factor can be applied to one of the first and second individual sensors.

3. The device of claim 1 wherein the first and second individual sensors comprise GMR resistive strips.

4. The device of claim 3 wherein the differential temperature sensor comprises first and second temperature sensors, each of the first and second temperature sensors respectively disposed thermally proximate a GMR resistive strip.

5. The device of claim 4 wherein the GMR resistive strips are spaced at least approximately 1.25 mm.

6. The device of claim 4 wherein the temperature sensors comprise pn junctions having a current responsive to temperature.

7. The device of claim 6 wherein the current through the first and second temperature sensors is differenced and multiplied by a constant prior to being combined with current from the current source.

8. The device of claim 1 wherein the sensors comprises a Hall effect sensor.

9. A sensor comprising:

a pair of individual giant magneto resistive (GMR) strips spaced apart from each other;

a current source configured to provide current to both of the strips;

means for sensing a difference in temperature of the strips to provide a temperature difference signal; and

means for combining the temperature difference signal with current from the current source to provide a correction factor for a temperature gradient across the individual sensors.

10. The sensor of claim 9 wherein the correction factor is applied to one of the GMR resistive strips.

11. The sensor of claim 9 wherein the means for sensing temperature comprises a pair of temperature sensors, each temperature sensor coupled thermally to respective GMR resistive strips.

12. The sensor of claim 11 wherein the temperature sensors comprise pn junctions having a current responsive to temperature.

13. The sensor of claim 11 wherein the current through the temperature sensors is differenced and multiplied by a constant prior to being combined with current from the current source.

14. The sensor of claim 9 wherein the GMR resistive strips are spaced at least approximately 1.25 mm.

15. A sensor comprising:

a pair of individual giant magneto resistive (GMR) strips spaced apart from each other;

an excitation source configured to provide excitation to both of the strips; and

means for providing a correction factor to the excitation of at least one of the strips as a function of a differential temperature across the strips.

16. A method comprising:

providing a substantially equal current to two sensors that are spaced apart from each other;

sensing a difference in temperature proximate the two sensors to provide a temperature difference signal; and

combining the temperature difference signal with current from the current source to provide a correction factor for a temperature gradient across the individual sensors.

17. A device comprising:

first and second sensors spaced apart from each such that they may be at different first and second temperatures;

a first excitation source positioned to be at a temperature between the different first and second temperatures;

a second excitation source positioned proximate the first temperature to provide electrical excitation as a function of the first temperature; and

a third excitation source positioned proximate the second temperature to provide electrical excitation as a function of the second temperature, wherein the first, second, and third excitation sources are selectively coupled to the first and second sensors to provide a correction factor for a temperature gradient across the first and second sensors.

18. The device of claim 17 wherein the first excitation source is positioned approximately in the middle of the temperature gradient across the first and second sensors.

19. The device of claim 18 wherein the temperature gradient is linear.

20. The device of claim 17 wherein the first, second, and third excitation sources are current sources or voltage sources.

21. A device comprising:

a first sensor and a second sensor spaced apart from each other such that they may be at different respective first and second temperatures;

a first current source positioned to be at a temperature between the different first and second temperatures and capable of providing equal first currents to the first and second sensors;

a second current source positioned proximate the first temperature and capable of providing a second current to the second sensor a function of the first temperature; and

a third current source positioned proximate the second temperature and capable of providing a third current to the first sensor as a function of the second temperature, wherein the second and third currents are capable of providing a correction factor for a temperature gradient across the individual sensors.

22. The device of claim 21 wherein the first and second sensors are giant magneto resistive (GMR) sensors.