Frequency and/or phase compensated microelectromechanical oscillator

• US 7,221,230 B2
• Filed: 09/30/2005
• Issued: 05/22/2007
• Est. Priority Date: 01/09/2004
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Partridge, Aaron, Lutz, Markus
• Primary Examiner(s): MIS, DAVID C
• Application Number:
  US11/240,010
• Publication Number:
  US 20060033589A1
• Time in Patent Office: 599 Days
• Field of Search: 331/18, 331/66, 331/74, 331/75, 331/116.R, 331/116.FE, 331/116.M, 331/154, 331/156, 331/175, 331/176
• US Class Current: 331/66
• 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: 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
• CPC Class Codes: H03L 1/026 by using a memory for digitally storing correction values H03L1/025 takes precedence
• CPC Class Codes: H03L 1/027 by using frequency conversion means which is variable with temperature, e.g. mixer, frequency divider, pulse add/substract logic circuit H03L1/023, H03L1/026 take precedence
• CPC Class Codes: H03L 1/04 Constructional details for maintaining temperature constant
• CPC Class Codes: H03L 7/07 using several loops, e.g. for redundant clock signal generation
• CPC Class Codes: H03L 7/08 Details of the phase-locked loop
• CPC Class Codes: H03L 7/1974 for fractional frequency division

Abstract

There are many inventions described and illustrated herein. In one aspect, the present invention is directed to a compensated microelectromechanical oscillator, having a microelectromechanical resonator that generates an output signal and frequency adjustment circuitry, coupled to the microelectromechanical resonator to receive the output signal of the microelectromechanical resonator and, in response to a set of values, to generate an output signal having second frequency. In one embodiment, the values may be determined using the frequency of the output signal of the microelectromechanical resonator, which depends on the operating temperature of the microelectromechanical resonator and/or manufacturing variations of the microelectromechanical resonator. In one embodiment, the frequency adjustment circuitry may include frequency multiplier circuitry, for example, PLLs, DLLs, digital/frequency synthesizers and/or FLLs, as well as any combinations and permutations thereof. The frequency adjustment circuitry, in addition or in lieu thereof, may include frequency divider circuitry, for example, DLLs, digital/frequency synthesizers (for example, DDS) and/or FLLs, as well as any combinations and permutations thereof.

Claims

1. A microelectromechanical oscillator, comprising:

a microelectromechanical resonator to generate an output signal wherein the output signal includes a first frequency;

frequency adjustment means for generating an output signal having a second frequency using the output signal of the microelectromechanical resonator and a set of values, wherein;

(i) the frequency adjustment means includes first frequency multiplier means, and (ii) the second frequency is greater than the first frequency; and

wherein the microelectromechanical resonator and the frequency adjustment means are integrated in or on a common substrate.

2. The microelectromechanical oscillator of claim 1 wherein the set of values is determined, at least in part, using information which is representative of the first frequency.

3. The microelectromechanical oscillator of claim 2 wherein the first frequency depends, at least in part, on an operating temperature of the microelectromechanical resonator.

4. The microelectromechanical oscillator of claim 1 wherein the values are determined using empirical data or mathematical modeling.

5. The microelectromechanical oscillator of claim 1 wherein the values are determined during (i) testing of the microelectromechanical resonator and/or microelectromechanical oscillator, (ii) calibration of the microelectromechanical oscillator, or (iii) operation of the microelectromechanical oscillator.

6. The microelectromechanical oscillator of claim 1 wherein the frequency adjustment means further includes:

frequency divider means for generating an output signal using (1) a first subset of values and (2) the output signal of the microelectromechanical resonator, wherein the frequency of the output signal of the frequency divider means is less than the frequency of the output signal of the microelectromechanical resonator;

wherein the first frequency multiplier means uses (1) a second subset of values and (2) the output signal of the frequency divider means, for generating the output signal having the second frequency; and

wherein the set of values includes the first subset of values and the second subset of values.

7. The microelectromechanical oscillator of claim 1 wherein:

the first frequency multiplier means generates an output signal using (i) a first subset of values and (ii) the output signal of the microelectromechanical resonator;

the frequency adjustment means further includes frequency divider means for generating the output signal having the second frequency using a second subset of values; and

wherein the set of values includes the first subset of values and the second subset of values.

8. The microelectromechanical oscillator of claim 1 wherein the

first frequency multiplier means generates an output signal, having a frequency, using (1) a first subset of values and (2) the output signal of the microelectromechanical resonator, wherein the frequency of the output signal of the first frequency multiplier means is greater than the first frequency;

the frequency adjustment means further includes second frequency multiplier means for generating the output signal having the second frequency using (1) a second subset of values and (2) the output signal of the first frequency multiplier means; and

wherein the set of values includes the first subset of values and the second subset of values.

9. The microelectromechanical oscillator of claim 1 wherein the first frequency depends, at least in part, on an operating temperature of the microelectromechanical resonator and wherein the microelectromechanical oscillator further includes temperature sensor means for determining information which is representative of the operating temperature of the resonator, an operating temperature of the microelectromechanical oscillator or an operating temperature of the frequency adjustment means.

10. The microelectromechanical oscillator of claim 9 wherein the values are determined during (i) calibration of the microelectromechanical oscillator or (ii) operation of the microelectromechanical oscillator.

11. The microelectromechanical oscillator of claim 9 further including temperature sensing means for providing data which is representative of temperature to the temperature sensor means.

12. A compensated microelectromechanical oscillator, comprising:

a microelectromechanical resonator to generate an output signal wherein the output signal includes a frequency;

frequency adjustment means for generating an output signal using the output signal of the microelectromechanical resonator and a set of values, wherein;

(i) the frequency adjustment means includes frequency divider means comprising a PLL, DLL, FLL or digital/frequency synthesizer, and

(ii) the output signal of frequency adjustment means includes a frequency that is less than the frequency of the output signal of the microelectromechanical resonator.

13. The microelectromechanical oscillator of claim 12 wherein the set of values is determined, at least in part, using information which is representative of the first frequency.

14. The microelectromechanical oscillator of claim 13 wherein the first frequency depends, at least in part, on an operating temperature of the microelectromechanical resonator.

15. The microelectromechanical oscillator of claim 12 wherein the values are determined using empirical data or mathematical modeling.

16. The microelectromechanical oscillator of claim 12 wherein the values are determined during (i) testing of the microelectromechanical resonator and/or microelectromechanical oscillator, (ii) calibration of the microelectromechanical oscillator, or (iii) operation of the microelectromechanical oscillator.

17. The microelectromechanical oscillator of claim 12 wherein the set of values are determined using an estimated frequency of the output signal of the microelectromechanical resonator and wherein the estimated frequency is determined using empirical data or mathematical modeling.

18. The microelectromechanical oscillator of claim 12 wherein the frequency adjustment means further includes:

frequency multiplier means for generating an output signal having a frequency using (1) a first set of values and (2) the output signal of the microelectromechanical resonator, wherein the frequency of the output signal of the frequency multiplier means is greater than the frequency of the output signal of the microelectromechanical resonator; and

wherein the frequency divider means generates the output signal having the output frequency using a second set of values.

19. The microelectromechanical oscillator of claim 12 wherein the frequency divider means generates an output signal having a frequency using (1) a first set of values and (2) the output signal of the microelectromechanical resonator;

and

wherein frequency adjustment means further includes frequency multiplier means for generating the output signal having the output frequency using a second set of values.

20. The microelectromechanical oscillator of claim 12 wherein the first frequency depends, at least in part, on an operating temperature of the microelectromechanical resonator and wherein the microelectromechanical oscillator further includes temperature sensor means, integrated in or on the common substrate, for determining information which is representative of the operating temperature of the resonator, an operating temperature of the microelectromechanical oscillator or an operating temperature of the frequency adjustment means.

21. The microelectromechanical oscillator of claim 20 wherein the values are determined during (i) calibration of the microelectromechanical oscillator or (ii) operation of the microelectromechanical oscillator.

22. The microelectromechanical oscillator of claim 20 further including temperature sensors to provide data which is representative of temperature to the temperature sensor means.

23. The microelectromechanical oscillator of claim 12 wherein the microelectromechanical resonator and the frequency adjustment means are integrated in or on a common substrate.

24. A method of operating a microelectromechanical oscillator having (1) a microelectromechanical resonator, integrated in or on a substrate, to generate an output signal wherein the output signal includes a first frequency, and (2) frequency adjustment means for generating an output signal having a second frequency in response to a first set of values, wherein the second frequency is (i) within a predetermined range of frequencies and (ii) greater than the first frequency, the method comprising:

determining that the microelectromechanical resonator is at a second operating temperature; and

providing a second set of values to the frequency adjustment means, wherein the frequency adjustment means, in response to the second set of values, generates an output signal having a frequency that is (1) within the predetermined range of frequencies when the microelectromechanical resonator is at the second operating temperature and (2) greater than the frequency of the output signal of the microelectromechanical resonator.

25. The method of claim 24 further including:

determining the second set of values wherein the frequency adjustment means, in response to the second set of values, provides the output signal having the frequency that is within the predetermined range of frequencies when the microelectromechanical resonator is at the second operating temperature; and

storing the second set of values in a memory means of the compensated microelectromechanical oscillator.

26. The method of claim 24 further including determining the second set of values during (i) testing of the microelectromechanical resonator and/or microelectromechanical oscillator, (ii) calibration of the microelectromechanical oscillator, or (iii) operation of the microelectromechanical oscillator.

27. The method of claim 24 further including:

measuring the temperature of the microelectromechanical resonator; and

calculating the operating temperature of the microelectromechanical resonator.

28. The method of claim 24 wherein the frequency adjustment means includes:

frequency divider means for generating an output signal having a frequency using a first subset of values and the output signal of the microelectromechanical resonator;

frequency multiplier means for generating the output signal of the frequency adjustment means using a second subset of values and the output signal of the frequency divider means; and

wherein the second set of values includes the first and second subsets of values, and

the method further comprises providing the first subset of values to the frequency divider means and the second subset of values to the frequency multiplier means, wherein the frequency adjustment means, in response to the first and second subsets of values, provides the output signal having the frequency that is within the predetermined range of frequencies when the microelectromechanical resonator is at the second operating temperature.

29. The method of claim 28 further including calculating the first and second subsets of values using empirical data or mathematical modeling.

30. The method of claim 29 further including determining the first and/or second subset of values during (i) testing of the microelectromechanical resonator or microelectromechanical oscillator, (ii) calibration of the microelectromechanical oscillator, or (iii) operation of the microelectromechanical oscillator.

31. The method of claim 24 wherein the frequency adjustment means includes:

first frequency multiplier means for generating an output signal having a frequency using a first subset of values wherein the frequency of the output signal is greater than the first frequency;

second frequency multiplier means for generating the output signal of the frequency adjustment means using a second subset of values and the output signal of the first frequency multiplier means wherein the second frequency is greater than the frequency of the output signal of the first frequency multiplier means; and

wherein the second set of values includes the first and second subsets of values, and

the method further comprises providing the first subset of values to the first frequency multiplier means and the second subset of values to the second frequency multiplier means, wherein the frequency adjustment means, in response to the first and second subsets of values, provides the output signal having the frequency that is (1) within the predetermined range of frequencies when the microelectromechanical resonator is at the second operating temperature and (2) greater than the frequency of the output signal of the microelectromechanical resonator.

32. The method of claim 31 further including calculating the first and second subsets of values using empirical data or mathematical modeling.

33. The method of claim 31 further including determining the first and/or second subset of values during (i) testing of the microelectromechanical resonator or microelectromechanical oscillator, (ii) calibration of the microelectromechanical oscillator, or (iii) operation of the microelectromechanical oscillator.

34. The method of claim 24 wherein the frequency adjustment means includes:

frequency multiplier means for generating an output signal having a frequency using a first subset of values wherein the frequency of the output signal is greater than the first frequency;

frequency divider means generating the Output signal having the second frequency using a second subset of values wherein the second frequency is greater than the frequency of the output signal of the microelectromechanical resonator; and

wherein the second set of values includes the first and second subsets of values, and

the method further comprises providing the first subset of values to the frequency multiplier means and the second subset of values to the frequency divider means, wherein the frequency adjustment means, in response to the first and second subsets of values, provides the output signal having the frequency that is (1) within the predetermined range of frequencies when the microelectromechanical resonator is at the second operating temperature and (2) greater than the frequency of the output signal of the microelectromechanical resonator.

35. The method of claim 34 further including calculating the first and second subsets of values using empirical data or mathematical modeling.

36. The method of claim 34 further including determining the first and/or second subset of values during (i) testing of the microelectromechanical resonator or microelectromechanical oscillator, (ii) calibration of the microelectromechanical oscillator, or (iii) operation of the microelectromechanical oscillator.

37. A microelectromechanical oscillator, comprising:

a microelectromechanical resonator to generate an output signal wherein the output signal includes a first frequency;

frequency adjustment means for generating a first output signal having a frequency using the output signal of the microelectromechanical resonator and a set of values, wherein;

(i) the frequency adjustment means includes first frequency multiplier means, and

(ii) the frequency of the first output signal is greater than the first frequency.

38. The microelectromechanical oscillator of claim 37 wherein the set of values Is determined, at least In part, using information which is representative of the first frequency.

39. The microelectromechanical oscillator of claim 38 wherein the first frequency depends, at least in part, on an operating temperature of the microelectromechanical resonator.

40. The microelectromechanical oscillator of claim 37 wherein the values are determined using empirical data or mathematical modeling.

41. The microelectromechanical oscillator of claim 37 wherein the values are determined during (i) testing of the microelectromechanical resonator and/or microelectromechanical oscillator, (ii) calibration of the microelectromechanical oscillator, or (iii) operation of the microelectromechanical oscillator.

42. The microelectromechanical oscillator of claim 37 wherein the frequency adjustment means generates first and second output signals, wherein:

first frequency multiplier means generates the first output signal using (1) a first subset of values and (2) the output signal of the microelectromechanical resonator;

second frequency multiplier means generates the second output signal having a frequency using (1) a first subset of values and (2) the output signal of the microelectromechanical resonator, wherein the frequency of the second output signal is different from the frequency of the first output signal; and

wherein the set of values includes the first subset of values and the second subset of values.

43. The microelectromechanical oscillator of claim 42 wherein the first frequency depends, at least in part, on an operating temperature of the microelectromechanical resonator and wherein the microelectromechanical oscillator further includes temperature sensor means for determining information which is representative of the operating temperature of the resonator, an operating temperature of the microelectromechanical oscillator or an operating temperature of the frequency adjustment means.

44. The microelectromechanical oscillator of claim 43 wherein the values are determined during (i) calibration of the microelectromechanical oscillator or (ii) operation of the microelectromechanical oscillator.

45. The microelectromechanical oscillator of claim 43 further including temperature sensing means for providing data which is representative of temperature to the temperature sensor means.

46. The microelectromechanical oscillator of claim 37 wherein the microelectromechanical resonator and the frequency adjustment means are integrated in or on a common substrate.

47. The microelectromechanical oscillator of claim 37 wherein the first frequency depends, at least in part, on an operating temperature of the microelectromechanical resonator and wherein the microelectromechanical oscillator further includes temperature sensor means for determining information which is representative of the operating temperature of the resonator, an operating temperature of the microelectromechanical oscillator or an operating temperature of the frequency adjustment means.

48. The microelectromechanical oscillator of claim 47 wherein the values are determined during (i) calibration of the microelectromechanical oscillator or (ii) operation of the microelectromechanical oscillator.

49. The microelectromechanical oscillator of claim 47 further including temperature sensing means for providing data which is representative of temperature to the temperature sensor means.