System and method for temperature sensing

Patent metadata

Field	Value
Publication number	US-10228294-B2
Application number	US-201615153577-A
Country	US
Kind code	B2
Filing date	May 12, 2016
Priority date	May 12, 2016
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

A method includes post processing a plurality of temperature sensors grouped into a plurality of sets. For each set of the plurality of sets, a post-processing system coupled to corresponding temperature sensors receives a plurality output signals generated by the corresponding temperature sensors. For each set of the plurality of sets, the post-processing system computes values representing proportional to absolute temperature (PTAT) voltages and values representing internal reference voltages based on output signals generated by the corresponding temperature sensors. For each set of the plurality of sets, the post-processing system computes an average of the values representing the PTAT voltages and relative PTAT voltage variation coefficients. For each set of the plurality of sets, the post-processing system computes values representing corrected PTAT voltages using the relative PTAT voltage variation coefficients.

First claim

What is claimed is:

1. A method comprising:
post processing a plurality of temperature sensors grouped into a plurality of sets, for each set of the plurality of sets:
receiving, by a post-processing system coupled to corresponding temperature sensors, a plurality of output signals generated by the corresponding temperature sensors;
reading post-processing parameters stored in non-volatile memories of the corresponding temperature sensors;
computing, by the post-processing system, values representing proportional to absolute temperature (PTAT) voltages and values representing internal reference voltages based on the plurality of output signals generated by the corresponding temperature sensors;
computing, by the post-processing system, an average of the values representing the PTAT voltages and relative PTAT voltage variation coefficients;
computing, by the post-processing system, values representing corrected PTAT voltages using the relative PTAT voltage variation coefficients;
computing, by the post-processing system, corner correction coefficients and curvature correction coefficients for the corresponding temperature sensors; sensors based on the post-processing parameters;
computing, by the post-processing system, estimated temperatures of the corresponding temperature sensors based on the values representing the PTAT voltages; and
correcting, by the post-processing system, the estimated temperatures of the corresponding temperature sensors by adding linear correction terms to the estimated temperatures to obtain the sensed temperatures of the corresponding temperature sensors, the linear correction terms being proportional to sums of the corner correction coefficients and the curvature correction coefficients.

2. The method of claim 1 , wherein computing the corner correction coefficients comprises:
computing, by the post-processing system, values representing the internal reference voltages at a reference temperature; and
computing, by the post-processing system, differences between the values representing the internal reference voltages at the reference temperature and a value representing a target internal reference voltage.

3. The method of claim 1 , wherein computing the curvature correction coefficients comprises computing, by the post-processing system, values representing shifted bandgap reference voltages based on the values representing the internal reference voltages and the values representing the PTAT voltages, the values representing the shifted bandgap reference voltages having approximately linear temperature dependences within a target temperature range of the plurality of temperature sensors.

4. The method of claim 1 , further comprising, for each set of the plurality of sets, calibrating analog-to-digital converters (ADCs) of the corresponding temperature sensors to obtain gain coefficients.

5. The method of claim 4 , further comprising, for each set of the plurality of sets, computing, by the post-processing system, corrected gain coefficients using the relative PTAT voltage variation coefficients.

6. The method of claim 4 , further comprising, for each set of the plurality of sets, storing the corrected gain coefficients in non-volatile memories of the corresponding temperature sensors.

7. The method of claim 6 , further comprising, for each set of the plurality of sets, storing the values representing corresponding corrected PTAT voltages and the value representing corresponding internal reference voltages in non-volatile memories of the corresponding temperature sensors.

8. The method of claim 7 , further comprising, for each set of the plurality of sets, storing the corner correction coefficients and the curvature correction coefficients in the non-volatile memories of the corresponding temperature sensors.

9. The method of claim 1 , further comprising, for each set of the plurality of sets:
generating, by the corresponding temperature sensors, first output signals of the plurality of output signals, the first output signals being based on the PTAT voltages and the internal reference voltages generated by temperature sensing circuits of the corresponding temperature sensors; and
generating, by the corresponding temperature sensors, second output signals of the plurality of output signals, the second output signals being based on the PTAT voltages generated by the temperature sensing circuits of the corresponding temperature sensors and calibration reference voltages generated by reference voltage generators of the corresponding temperature sensors.

10. The method of claim 1 , further comprising setting a temperature of the plurality of temperature sensors to a calibration temperature using a thermal chuck.

11. The method of claim 10 , further comprising, for each set of the plurality of sets, computing, by the post-processing system, an average sensed calibration temperature for the corresponding temperature sensors.

12. The method of claim 11 , wherein the calibration temperature is non-uniform across the thermal chuck, and wherein a uniformity error of the thermal chuck is characterized by a characteristic function.

13. The method of claim 12 , further comprising narrowing a distribution of average sensed calibration temperatures of the plurality of sets using the characteristic function.

14. The method of claim 13 , further comprising centering the distribution of the average sensed calibration temperatures of the plurality of sets.

15. A method comprising:
receiving, by a post-processing system coupled to a temperature sensor, an output signal generated by the temperature sensor, the output signal being based on a proportional to absolute temperature (PTAT) voltage and an internal reference voltage generated by a temperature sensing circuit of the temperature sensor;
reading, by the post-processing system, device specific calibration coefficients and post-processing parameters stored in a non-volatile memory of the temperature sensor;
computing, by the post-processing system, a corner correction coefficient and a curvature correction coefficient based on the device specific calibration coefficients;
computing, by the post-processing system, a PTAT ratio based on the output signal; and
computing, by the post-processing system, a sensed temperature based on the PTAT ratio, the corner correction coefficient and the curvature correction coefficient.

16. The method of claim 15 , wherein computing the sensed temperature comprises:
computing, by the post-processing system, an estimated temperature based on the PTAT ratio; and
correcting, by the post-processing system, the estimated temperature by adding a linear correction term to the estimated temperature to obtain the sensed temperature, the linear correction term being proportional to a sum of the corner correction coefficient and the curvature correction coefficient.

17. The method of claim 15 , wherein computing the sensed temperature comprises:
correcting, by the post-processing system, mapping coefficients used for mapping the PTAT ratio to a temperature domain using the corner correction coefficient and the curvature correction coefficient to obtain corrected mapping coefficients; and
computing, by the post-processing system, the sensed temperature based on the PTAT ratio and the corrected mapping coefficients.

18. The method of claim 15 , further comprising:
calibrating the temperature sensor to determine the device specific calibration coefficients; and
storing the device specific calibration coefficients in the non-volatile memory.

Assignees

• Infineon Technologies Ag

Inventors

• Bach Elmar
• Greco Patrizia
• Wiesbauer Andreas
• Choong Kwan Siong Kenneth
• Staber Michael

Classifications

• G01K15/005 Primary

  Calibration · CPC title

• G01K13/00 Primary

  Thermometers specially adapted for specific purposes · CPC title

• G01K15/002

  Calibrated temperature sources, temperature standards therefor (arrangements with respect to the cold junction of thermo-electric elements G01K7/12) · CPC title

• G01K7/01 Primary

  using semiconducting elements having PN junctions (G01K7/02, G01K7/16, G01K7/30 take precedence) · CPC title