Temperature measurement system having a plurality of microelectromechanical resonators and method of operating same

• US 7,446,619 B2
• Filed: 06/14/2006
• Issued: 11/04/2008
• Est. Priority Date: 06/14/2006
• Status: Active Grant

• Current Assignee: SiTime Corporation (Megachips Corporation)
• Original Assignee: SiTime Corporation (Megachips Corporation)
• Inventors: Partridge, Aaron, Lutz, Markus, Boser, Bernhard E., Lu, Crist Y.
• Primary Examiner(s): Pascal; Robert J.
• Assistant Examiner(s): Goodley; James E
• Application Number:
  US11/453,314
• Publication Number:
  US 20080007362A1
• Time in Patent Office: 874 Days
• Field of Search: 331/116.M, 331/154, 331/156
• US Class Current: 331/156
• CPC Class Codes: G01K 7/32 using change of resonant frequency of a crystal
• CPC Class Codes: H03B 5/04 Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature
• CPC Class Codes: H03B 5/30 with frequency-determining element being electromechanical resonator
• CPC Class Codes: H03H 2009/02527 Combined
• CPC Class Codes: H03H 9/02448 of temperature influence
• CPC Class Codes: H03H 9/2405 of microelectro-mechanical resonators
• CPC Class Codes: H03L 1/022 by indirect stabilisation, i.e. by generating an electrical correction signal which is a function of the temperature H03L1/021 takes precedence

Abstract

There are many inventions described and illustrated herein. In one aspect, the present inventions relate to a temperature measurement system comprising (1) a first microelectromechanical resonator to generate a first output signal having a frequency that varies with operating temperature, wherein the first microelectromechanical resonator includes a frequency function of temperature; (2) a second microelectromechanical resonator to generate a second output signal having a frequency that varies with operating temperature, wherein the second microelectromechanical resonator includes a frequency function of temperature; and (3) frequency division circuitry, coupled to the first and second microelectromechanical resonators, to determine data which is representative of the operating temperature of the first and/or second microelectromechanical resonator using (i) data which is representative of the frequency of the first output signal and (ii) data which is representative of the frequency of the second output signal. The frequency division circuitry may include circuitry to divide the frequency of the first output signal by the frequency of the second output signal (whether in digital or analog domain).

Claims

1. A temperature measurement system, comprising:

a first microelectromechanical resonator to generate a first output signal having a frequency that varies with operating temperature, wherein the first microelectromechanical resonator includes a frequency function of temperature;

a second microelectromechanical resonator to generate a second output signal having a frequency that varies with operating temperature, wherein the second microelectromechanical resonator includes a frequency function of temperature; and

frequency division circuitry, coupled to the first and second microelectromechanical resonators, to determine data which is representative of the operating temperature of the first and/or second microelectromechanical resonator using (i) data which is representative of the frequency of the first output signal and (ii) data which is representative of the frequency of the second output signal.

2. The temperature measurement system of claim 1 wherein the frequency division circuitry includes circuitry to divide the frequency of the first output signal by the frequency of the second output signal in a digital domain.

3. The temperature measurement system of claim 2 wherein the frequency division circuitry includes counter circuitry and/or analog-to-digital converter circuitry.

4. The temperature measurement system of claim 2 wherein the frequency division circuitry further includes:

first counter circuitry, coupled to first microelectromechanical resonator, to generate the data which is representative of the frequency of the first output signal;

second counter circuitry, coupled to second microelectromechanical resonator, to generate the data which is representative of the frequency of the second output signal;

analysis circuitry, coupled to the first and second counter circuitry, to divide the data which is representative of the frequency of the first output signal by the data which is representative of the frequency of the second output signal.

5. The temperature measurement system of claim 2 the frequency division circuitry further includes:

first counter circuitry, coupled to first microelectromechanical resonator, to generate the data which is representative of the frequency of the first output signal;

second counter circuitry, coupled to second microelectromechanical resonator, to generate the data which is representative of the frequency of the second output signal;

analysis circuitry, coupled to the first and second counter circuitry, to determine the data which is representative of the operating temperature of the first and/or second microelectromechanical resonators by dividing (i) the data which is representative of the frequency of the first output signal by (ii) the data which is representative of the frequency of the second output signal.

6. The temperature measurement system of claim 1 wherein the frequency division circuitry includes circuitry to divide the frequency of the first output signal by the frequency of the second output signal in an analog domain.

7. The temperature measurement system of claim 6 wherein the frequency division circuitry includes:

first frequency to voltage converter circuitry, coupled to first microelectromechanical resonator, to generate the data which is representative of the frequency of the first output signal;

second frequency to voltage converter circuitry, coupled to second microelectromechanical resonator, to generate the data which is representative of the frequency of the second output signal;

analog to voltage divider circuitry, coupled to the first and second frequency to voltage converter circuitry, to determine the data which is representative of the operating temperature of the first and/or second microelectromechanical resonator using (i) the data which is representative of the frequency of the first output signal and (ii) the data which is representative of the frequency of the second output signal.

8. The temperature measurement system of claim 1 wherein the first microelectromechanical resonator and the second microelectromechanical resonator are the same physical structure.

9. The temperature measurement system of claim 1 wherein the first microelectromechanical resonator and the second microelectromechanical resonator include different crystalline orientations or directions in or on the same substrate.

10. The temperature measurement system of claim 1 further including processor circuitry, coupled to the frequency division circuitry, to determine the operating temperature of the first microelectromechanical resonator and/or the second microelectromechanical resonator using the data which is representative of the operating temperature of the first and/or second microelectromechanical resonators.

11. The temperature measurement system of claim 1 wherein the processor circuitry determines the operating temperature of the first microelectromechanical resonator and/or the second microelectromechanical resonator using a look-up table.

12. The temperature measurement system of claim 1 wherein the processor circuitry determines the operating temperature of the first microelectromechanical resonator and/or the second microelectromechanical resonator using a mathematical relationship.

13. A temperature measurement system, comprising:

a first microelectromechanical resonator to generate a first output signal having a frequency that varies with operating temperature, wherein the first microelectromechanical resonator includes a frequency function of temperature;

a second microelectromechanical resonator to generate a second output signal having a frequency that varies with operating temperature, wherein the second microelectromechanical resonator includes a frequency function of temperature;

frequency division circuitry, coupled to the first and second microelectromechanical resonators, wherein the frequency division circuitry includes;

circuitry to generate;

data which is representative of the frequency of the first output signal; and

data which is representative of the frequency of the second output signal; and

analysis circuitry to determine data which is representative of the operating temperature of the first and/or second microelectromechanical resonators by dividing (i) the data which is representative of the frequency of the first output signal by (ii) the data which is representative of the frequency of the second output signal; and

processor circuitry, coupled to the frequency division circuitry, to determine the operating temperature of the first and/or second microelectromechanical resonator using the data which is representative of the operating temperature of the first and/or second microelectromechanical resonators.

14. The temperature measurement system of claim 13 wherein the analysis circuitry divides the frequency of the first output signal by the frequency of the second output signal in a digital domain.

15. The temperature measurement system of claim 13 wherein the analysis circuitry divides the frequency of the first output signal by the frequency of the second output signal in an analog domain.

16. The temperature measurement system of claim 15 wherein the circuitry to generate the data which is representative of the frequency of the first output signal and the data which is representative of the frequency of the second output signal includes:

first frequency to voltage converter circuitry, coupled to first microelectromechanical resonator, to generate the data which is representative of the frequency of the first output signal;

second frequency to voltage converter circuitry, coupled to second microelectromechanical resonator, to generate the data which is representative of the frequency of the second output signal; and

wherein the analysis circuitry is analog to voltage divider circuitry, coupled to the first and second frequency to voltage converter circuitry, to determine the data which is representative of the operating temperature of the first and/or second microelectromechanical resonator using (i) the data which is representative of the frequency of the first output signal and (ii) the data which is representative of the frequency of the second output signal.

17. The temperature measurement system of claim 13 wherein the first microelectromechanical resonator and the second microelectromechanical resonator are the same physical structure.

18. The temperature measurement system of claim 13 wherein the first microelectromechanical resonator and the second microelectromechanical resonator include different crystalline orientations or directions in or on the same substrate.

19. The temperature measurement system of claim 13 wherein the processor circuitry determines the operating temperature of the first microelectromechanical resonator and/or the second microelectromechanical resonator using a look-up table.

20. The temperature measurement system of claim 13 wherein the processor circuitry determines the operating temperature of the first microelectromechanical resonator and/or the second microelectromechanical resonator using a mathematical relationship.

21. A temperature measurement system, comprising:

a first microelectromechanical resonator to generate a first output signal having a frequency that varies with operating temperature, wherein the first microelectromechanical resonator includes a frequency function of temperature;

a second microelectromechanical resonator to generate a second output signal having a frequency that varies with operating temperature, wherein the second microelectromechanical resonator includes a frequency function of temperature;

frequency division circuitry, coupled to the first and second microelectromechanical resonators, wherein the frequency division circuitry includes;

circuitry to generate;

data which is representative of the frequency of the first output signal; and

data which is representative of the frequency of the second output signal; and

analysis circuitry to determine data which is representative of the operating temperature of the first and/or second microelectromechanical resonators by dividing (i) the data which is representative of the frequency of the first output signal by (ii) the data which is representative of the frequency of the second output signal;

processor circuitry, coupled to the frequency division circuitry, to determine the operating temperature of the first and/or second microelectromechanical resonator using the data which is representative of the operating temperature of the first and/or second microelectromechanical resonators; and

wherein the first and second microelectromechanical resonators are disposed on and/or in the same substrate and the frequency division circuitry and the processor circuitry are disposed on or in the same substrate.

22. The temperature measurement system of claim 21 wherein the first and second microelectromechanical resonators, the frequency division circuitry and the processor circuitry are disposed on or in the same substrate.

23. The temperature measurement system of claim 21 wherein the frequency division circuitry includes circuitry to divide the frequency of the first output signal by the frequency of the second output signal in a digital domain.

24. The temperature measurement system of claim 21 wherein the frequency division circuitry includes counter circuitry and/or analog-to-digital converter circuitry.

25. The temperature measurement system of claim 21 wherein the frequency division circuitry includes circuitry to divide the frequency of the first output signal by the frequency of the second output signal in an analog domain.