Precision temperature measurement devices, sensors, and methods

Patent metadata

Field	Value
Publication number	US-9658118-B2
Application number	US-201314080625-A
Country	US
Kind code	B2
Filing date	Nov 14, 2013
Priority date	Nov 16, 2012
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A precision temperature sensing system includes a heater and a sensing element disposed on a semiconductor substrate. A power source drives the heater on a periodic basis according to a received clock signal. The sensing element senses the heat emitted by the heater and diffused through the semiconductor substrate. Processing circuitry coupled to the sensing element adjusts a phase of the periodic heater driving signal based on the heat sensed by the sensing element. The processing circuitry determines a temperature based on a thermal diffusivity (TD) of the semiconductor substrate, the adjusted value of the phase, and a known distance between the heater and the sensing element. A second temperature sensor can be disposed on the same substrate as the precision temperature sensing system, and calibrated based on temperature measurements obtained while applying a reference frequency signal to the precision sensing system.

First claim

What is claimed is:

1. A method for calibrating a first temperature sensor disposed on a substrate, the method comprising:
providing a second temperature sensor on the substrate having the first temperature sensor disposed thereon, wherein the second temperature sensor is operative to perform temperature measurements based on thermal diffusivity (TD);
obtaining a first temperature measurement using the first temperature sensor, wherein the first temperature sensor is operative to perform temperature measurements based on characteristics of a semiconductor junction, a bipolar transistor, or a MOSFET transistor;
substantially concurrently with the obtaining of the first temperature measurement, applying a reference frequency signal to the second temperature sensor and obtaining a second temperature measurement using the second temperature sensor;
computing, based on the first and second temperature measurements, a calibration adjustment value for the first temperature sensor operating based on the characteristics of a semiconductor junction, a bipolar transistor, or a MOSFET transistor; and
adjusting, based on the computed calibration adjustment value, a third temperature measurement from the first temperature sensor operating based on the characteristics of a semiconductor junction, a bipolar transistor, or a MOSFET transistor.

2. The method of claim 1 , further comprising:
applying heat or cold to the substrate, and obtaining a fourth temperature measurement using the first temperature sensor during or following the applying of the heat or cold; and
substantially concurrently with the obtaining of the fourth temperature measurement, applying the reference frequency signal to the second temperature sensor and obtaining a fifth temperature measurement using the second temperature sensor,
wherein the calibration adjustment value for the first temperature sensor is computed based on the first, second, fourth, and fifth temperature measurements.

3. The method of claim 2 , wherein the applying of the heat or cold to the substrate comprises providing power to a heater disposed on the substrate having the first and second temperature sensors disposed thereon.

4. The method of claim 1 , further comprising storing the computed calibration adjustment value in a non-volatile memory disposed on the substrate.

5. The method of claim 4 , wherein the storing of the computed calibration adjustment value comprises trimming a circuit element of the first temperature sensor disposed on the substrate to adjust an electrical parameter of the circuit element.

6. The method of claim 1 , further comprising:
monitoring the reference frequency signal applied to the second temperature sensor to obtain a reference frequency signal correction value,
wherein the calibration adjustment value for the first temperature sensor is computed based on the first and second temperature measurements and the obtained reference frequency signal correction value.

7. The method of claim 1 , wherein the applying the reference frequency signal to the second temperature sensor comprises activating an oscillator disposed on the substrate.

8. The method of claim 1 , wherein the applying the reference frequency signal to the second temperature sensor comprises receiving the reference frequency signal from an oscillator external to the substrate.

9. The method of claim 1 , further comprising:
providing a third temperature sensor on the substrate having the first and second temperature sensor disposed thereon, wherein the third temperature sensor is operative to perform temperature measurements based on thermal diffusivity (TD); and
substantially concurrently with the obtaining of the first and second temperature measurements, applying a reference frequency signal to the third temperature sensor and obtaining a fourth temperature measurement using the third temperature sensor,
wherein the computing the calibration adjustment value for the first temperature sensor comprises computing the calibration adjustment value based on the first, second, and fourth temperature measurements.

10. The method of claim 1 , further comprising:
providing a heater disposed on the semiconductor substrate;
driving the heater with a periodic signal to cause the heater to emit heat through the semiconductor substrate;
sensing heat emitted by the heater through the semiconductor substrate using the second temperature sensor;
adjusting a phase of the periodic signal driving the heater based on heat sensed by the second temperature sensor; and
determining the temperature based on an adjusted value of the phase applied to the periodic signal driving the heater.

11. The method of claim 10 , wherein the determining the temperature comprises determining the temperature based on the adjusted value of the phase applied to the periodic signal driving the heater, a thermal diffusivity of the semiconductor substrate, and a known distance between the heater and the second temperature sensor.

12. The method of claim 10 , wherein the sensing heat emitted by the heater comprises:
applying a current to a series interconnection of diodes; and
sensing a change in voltage across the series interconnection of diodes resulting from the heat emitted by the heater through the semiconductor substrate.

13. The method of claim 12 , wherein the adjusting the phase of the periodic signal comprises:
producing a current signal based on the change in voltage across the series interconnection of diodes;
integrating the current signal over a period of time;
quantizing the integrated current signal; and
selectively increasing or decreasing the phase of the periodic signal driving the heater based on the quantized integrated current signal.

14. The method of claim 10 , wherein the driving the heater with a periodic signal comprises driving the heater with a signal that alternates polarity in successive periods of the signal.

15. The method of claim 1 , wherein the first and second temperature sensors perform temperature measurements based on different operating principles.

Assignees

• Linear Tech Corp

Inventors

• Charles Gordon Alexander
• Lemkin Mark Alan

Classifications

• G01K15/005 Primary

  Calibration · CPC title

• G01K7/01

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