Temperature measurement circuit and method

Patent metadata

Field	Value
Publication number	US-12339175-B2
Application number	US-202217736157-A
Country	US
Kind code	B2
Filing date	May 4, 2022
Priority date	May 7, 2021
Publication date	Jun 24, 2025
Grant date	Jun 24, 2025

Abstract

Disclosed are a temperature measurement circuit and method. The circuit includes a first temperature sensing circuit, a second temperature sensing circuit and a data processing unit. The first temperature sensing circuit is configured to generate a first measurement signal for characterizing a temperature based on an inputted first current signal, a magnitude of the first current signal being correlated to temperature. The second temperature sensing circuit is configured to generate a second measurement signal for characterizing the temperature based on an inputted second current signal, the second current signal being independent of temperature. The data processing unit is configured to determine a current temperature based on a first characteristic parameter corresponding to the first measurement signal and a second characteristic parameter corresponding to the second measurement signal.

First claim

The invention claimed is:

1. A temperature measurement circuit, comprising: a first temperature sensing circuit, a second temperature sensing circuit, a data processing unit, a PTAT (Proportional To Absolute Temperature) current source whose output current having a magnitude that is positively proportional to absolute temperature and a constant current source, wherein
the first temperature sensing circuit is configured to generate a first measurement signal for characterizing temperature based on an inputted first current signal, a magnitude of the first current signal being correlated to temperature;
the second temperature sensing circuit is configured to generate a second measurement signal for characterizing temperature based on an inputted second current signal, the second current signal being independent of temperature;
an output terminal of the first temperature sensing circuit and an output terminal of the second temperature sensing circuit are connected to an input terminal of the data processing unit;
the data processing unit is configured to determine a current temperature based on a first characteristic parameter corresponding to the first measurement signal and a second characteristic parameter corresponding to the second measurement signal, wherein
a circuit parameter of the first temperature sensing circuit is the same as a circuit parameter of the second temperature sensing circuit;
the PTAT current source is configured to generate the first current signal having a magnitude varying with temperature, the constant current source is configured to generate a second current source having a constant magnitude;
an output terminal of the PTAT current source is connected to an input terminal of the first temperature sensing circuit; and
an output terminal of the constant current source is connected to an input terminal of the second temperature sensing circuit.

2. The temperature measurement circuit according to claim 1 , wherein the first measurement signal is correlated to temperature and the circuit parameter of the first temperature sensing circuit; and
the second measurement signal is correlated to the circuit parameter of the second temperature sensing circuit.

3. The temperature measurement circuit according to claim 1 , wherein the constant current source comprises the PTAT current source and an absolute temperature compensation circuit.

4. The temperature measurement circuit according to claim 1 , wherein the first temperature sensing circuit comprises a first ring oscillator, and the second temperature sensing circuit comprises a second ring oscillator;
a signal input terminal of the first ring oscillator is connected to the output terminal of the PTAT current source;
a signal input terminal of the second ring oscillator is connected to the output terminal of the constant current source.

5. The temperature measurement circuit according to claim 4 , wherein the first measurement signal is a first periodic oscillation signal generated by the first ring oscillator based on the first current signal;
the second measurement signal is a second periodic oscillation signal generated by the second ring oscillator based on the second current signal, the first characteristic parameter is a first oscillation frequency, and the second characteristic parameter is a second oscillation frequency; and
the data processing unit is configured to determine the current temperature based on the first oscillation frequency of the first period oscillation signal and the second oscillation frequency of the second period oscillation signal.

6. The temperature measurement circuit according to claim 4 , wherein each of the first ring oscillator and the second ring oscillator comprises an odd number of inverters.

7. The temperature measurement circuit according to claim 6 , wherein the first ring oscillator and the second ring oscillator comprise the same number of inverters.

8. The temperature measurement circuit according to claim 1 , wherein the second temperature sensing circuit is a mirror circuit of the first temperature sensing circuit.

9. A temperature measurement method applied to the data processing unit in the temperature measurement circuit according to claim 1 , the temperature measurement circuit comprising the first temperature sensing circuit, the second temperature sensing circuit, a PTAT (Proportional To Absolute Temperature) current source whose output current having a magnitude that is positively proportional to absolute temperature and a constant current source, and the temperature measurement method comprises:
receiving the first measurement signal outputted by the first temperature sensing circuit and the second measurement signal outputted by the second temperature sensing circuit, wherein the first current signal is inputted into the first temperature sensing circuit, the magnitude of the first current signal being correlated to temperature, and the second current signal is inputted into the second temperature sensing circuit, the second current signal being independent of temperature;
extracting the first characteristic parameter corresponding to the first measurement signal and the second characteristic parameter corresponding to the second measurement signal; and
determining a current temperature of an environment in which the temperature measurement circuit is located based on the first characteristic parameter and the second characteristic parameter;
wherein
the PTAT current source is configured to generate the first current signal having a magnitude varying with temperature, the constant current source is configured to generate a second current source having a constant magnitude;
an output terminal of the PTAT current source is connected to an input terminal of the first temperature sensing circuit; and
an output terminal of the constant current source is connected to an input terminal of the second temperature sensing circuit.

10. The method according to claim 9 , wherein
the first measurement signal is correlated to temperature and the circuit parameter of the first temperature sensing circuit; and
the second measurement signal is correlated to the circuit parameter of the second temperature sensing circuit.

11. The method according to claim 9 , wherein the constant current source comprises the PTAT current source and an absolute temperature compensation circuit.

12. The method according to claim 9 , wherein the first temperature sensing circuit comprises a first ring oscillator, and the second temperature sensing circuit comprises a second ring oscillator;
a signal input terminal of the first ring oscillator is connected to the output terminal of the PTAT current source;
a signal input terminal of the second ring oscillator is connected to the output terminal of the constant current source.

13. The method according to claim 12 , wherein the first measurement signal is a first periodic oscillation signal generated by the first ring oscillator based on the first current signal;
the second measurement signal is a second periodic oscillation signal generated by the second ring oscillator based on the second current signal, the first characteristic parameter is a first oscillation frequency, and the second characteristic parameter is a second oscillation frequency; and
the data processing unit is configured to determine the current temperature based on the first oscillation frequency of the first period oscillation signal and the second oscillation frequency of the second period oscillation signal.

14. The method according to claim 12 , wherein each of the first ring oscillator and the second

Assignees

• Lemon Inc

Inventors

• Zhang Chuang
• Lu Shan
• Zhang Junmou
• Chen Yimin
• Wang Jian
• Cheng Yuanlin

Classifications

• G01K7/20

  in a specially-adapted circuit, e.g. bridge circuit · CPC title

• G01K15/005

  Calibration · CPC title

• G01K1/20

  Compensating for effects of temperature changes other than those to be measured, e.g. changes in ambient temperature · CPC title

• G01K2219/00

  Thermometers with dedicated analog to digital converters · CPC title

• G01K7/203 Primary

  in an oscillator circuit · CPC title