System and Method for Providing Temperature Correction in a Crystal Oscillator

• US 20080164952A1
• Filed: 01/05/2007
• Published: 07/10/2008
• Est. Priority Date: 01/05/2007
• Status: Active Grant

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Babitch, Daniel
• Granted Patent: US 7,466,209 B2
• Time in Patent Office: Days
• US Class Current: 331/66
• CPC Class Codes: G01K 7/32 using change of resonant frequency of a crystal
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: H03L 1/026 by using a memory for digitally storing correction values H03L1/025 takes precedence
• CPC Class Codes: H03L 1/04 Constructional details for maintaining temperature constant

Abstract

A system and method for providing temperature compensation in a oscillator component (such as a crystal oscillator component) that includes a closely-located temperature sensing device. The crystal oscillator component in example systems and methods is exposed to a temperature profile during a calibration procedure. Temperature and frequency data are collected and applied to coefficient generating function according to a temperature compensation model to generate a set of coefficients that are used in the temperature compensation model in an application device. The generated coefficients are stored in a coefficient memory accessible to an application device during operation.

Claims

1. A method for configuring an oscillator component where the oscillator component includes a temperature sensor, the method comprising:

exposing the oscillator component to a controlled temperature environment;

operating the oscillator component so that the oscillator component outputs a frequency signal;

initiating a temperature test profile by setting the temperature at the oscillator component to a first initial temperature and varying the temperature according to the profile;

periodically measuring frequency and temperature as the temperature setting changes during the temperature test profile;

applying the measured frequency and temperature data to a temperature compensation model to generate a plurality of parameters that characterize the oscillator component, the parameters including dynamic response parameters that characterize a thermal dynamic response of the oscillator component; and

associating the generated plurality of parameters to the oscillator component.

2. The method of claim 1 where the step of applying the measured frequency and temperature data includes the step of:

generating the plurality of parameters as a set of coefficients according to;

frequency=(a₀+a₁T+a₂T²+a₃T³+a₄T⁴+ . . . +a_nTⁿ)+{(b_1,0+b_1,1T+b_1,2T²+b_1,3T³+b_1,4T⁴+ . . . +b_1,xT^x)*(b2,0+b_2,1R+ . . . +b_2,yR^y)}+(c₀+c₁T_f+ . . . c_mT_f^m)

where, T=temperature, R=filtered temperature ramp rate, T_f=filtered temperature, and a_n, b_1,x, b_2,y, and cm are coefficients calculated by curve fitting the acquired frequency and temperature data.

3. The method of claim 1 further comprising:

assembling a product containing the oscillator component before the step of exposing the oscillator component to the controlled temperature environment;

wherein the step of associating the calculated coefficients includes the step of storing the coefficients in memory in the product.

4. The method of claim 1 wherein the step of associating the generated parameters to the oscillator component includes:

determining a serial number for the oscillator component; and

storing the parameters with the serial number of the oscillator component.

5. The method of claim 1 wherein the step of associating the generated parameters to the oscillator component includes:

determining a serial number for the oscillator component; and

storing the parameters in a database accessible via a data network using the serial number as a link to the parameters.

6. The method of claim 5 further comprising the step of:

storing the serial number in a local coefficient memory located on the oscillator component.

7. The method of claim 4 further comprising the step of:

generating a barcoded label having a barcode encoded with the serial number of the oscillator component and the generated parameters.

8. The method of claim 1 further comprising the step of:

providing the oscillator component by selecting an oscillator component from a group consisting of a crystal oscillator component and a silicon microelectric mechanical system (“

MEMS”

) component.

9. A method for subjecting a oscillator component to a temperature test profile comprising:

performing a first stage of the temperature test profile by;

setting the temperature to an initial temperature;

continuously changing the temperature over a first period of time until a first temperature setting is reached;

continuously changing the temperature in a reverse direction over a second period of time until a second temperature setting is reached;

continuously changing the temperature in a reverse direction relative to the direction in the second period of time over a third period of time until a third temperature setting is reached;

performing a second stage of the temperature test profile by;

starting with the third temperature setting and changing the temperature in a direction opposite the direction of the temperature change during the third period of time until the second temperature setting is reached;

then changing the temperature in a direction opposite the direction of the temperature change during the second period of time; and

then changing the temperature in a direction opposite the direction of the temperature change during the first period of time until the initial temperature setting is reached.

10. A oscillator component for generating a signal having a frequency, the oscillator component comprising:

a component package that includes a oscillator circuit and a temperature sensing device located in substantially close proximity to the oscillator circuit, where the frequency generated by the oscillator component varies as a function of temperature characterized by a temperature compensation model associated with a plurality of parameters that characterize the component package, the parameters including dynamic response parameters that characterize a thermal dynamic response of the component package.

11. The oscillator component of claim 10 where the temperature compensation model is:

frequency=(a₀+a₁T+a₂T²+a₃T³+a₄T⁴+ . . . +a_nTⁿ)+{(b_1,0+b_1,1T+b_1,2T²+b_1,3T³+b_1,4T⁴+ . . . +b_1,xT^x)*(b2,0+b_2,1R+ . . . +b_2,yR^y)}

where, T=temperature, R=filtered temperature ramp rate, and a_n, b_1,x, b_2,y, are coefficients calculated by curvefitting frequency and temperature data acquired while subjecting the component package to a temperature test profile; and

where the plurality of parameters include the coefficients.

12. The oscillator component of claim 10 where the temperature compensation model is:

frequency=(a₀+a₁T+a₂T²+a₃T³+a₄T⁴+ . . . +a_nTⁿ)+{(b_1,0+b_1,1T+b_1,2T²+b_1,3T³+b_1,4T⁴+ . . . +b_1,xT^x)*(b2,0+b_2,1R+ . . . +b_2,yR^y)}+(c₀+c₁T_f+ . . . c_mT_f^m)

where, T=temperature, R=filtered temperature ramp rate, T_f=filtered temperature, and a_n, b_1,x, b_2,y, and c_m are coefficients calculated by curvefitting frequency and temperature data acquired while subjecting the component package to a temperature test profile; and

where the plurality of parameters include the coefficients.

13. The oscillator component of claim 10 where:

n=9;

x=5

y=2; and

m==1.

14. The oscillator component of claim 10 where the temperature sensing device includes a temperature sensor that outputs a voltage level that varies as a function of temperature.

15. The oscillator component of claim 14 further comprising an analog-to-digital converter (“

ADC”

) coupled to the temperature sensor to receive the voltage level.

16. The oscillator component of claim 10 where the temperature sensing device includes a second oscillator that generates a second signal having a second frequency that varies linearly with temperature.

17. The oscillator component of claim 10 where the component package further comprises a parameter memory for storing the plurality of parameters.

18. A device comprising:

a plurality of electronic components to perform a function that uses a signal having a frequency;

a oscillator circuit in a component package that includes a temperature sensing device located in substantially close proximity to the oscillator circuit, where the oscillator circuit generates the frequency used to perform the function, the frequency varying as a function of temperature characterized by a temperature compensation model associated with a plurality of parameters that characterize the component package, the parameters including dynamic response parameters that characterize a thermal dynamic response of the component package;

a parameter memory for storing the plurality of parameters; and

a frequency correction function coupled to the oscillator component to receive the frequency and to receive a signal indicative of the temperature from the temperature sensing device, the frequency correction function being operable to receive at least some of the plurality of parameters and to perform the temperature compensation model using the plurality of parameters.

19. The device of claim 18 where the temperature compensation model is:

frequency=(a₀+a₁T+a₂T²+a₃T³+a₄T⁴+ . . . +a_nTⁿ)+{(b_1,0+b_1,1T+b_1,2T²+b_1,3T³+b_1,4T⁴+ . . . +b_1,xT^x)*(b_2,0+b_2,1R+ . . . +b_2,yR^y)}

where, T=temperature, R=filtered temperature ramp rate, and a_n, b_1,x, b_2,y, are coefficients calculated by curvefitting frequency and temperature data acquired while subjecting the component package to a temperature test profile; and

where the plurality of parameters include the coefficients.

20. The device of claim 18 where the temperature compensation model is:

frequency=(a₀+a₁T+a₂T²+a₃T³+a₄T⁴+ . . . +a_nTⁿ)+{(b_1,0+b_1,1T+b_1,2T²+b_1,3T³+b_1,4T⁴+ . . . +b_1,xT^x)*(b_2,0+b_2,1R+ . . . +b_2,yR^y)}+(c₀+c₁T_f+ . . . cT_mT_f^m)

where, T=temperature, R=filtered temperature ramp rate, T_f=filtered temperature, and a_n, b_1,x, b_2,y, and c_m are coefficients calculated by curvefitting frequency and temperature data acquired while subjecting the component package to a temperature test profile; and

where the plurality of parameters include the coefficients.

21. The device of claim 18 where:

the temperature sensing device includes a temperature sensor that outputs a voltage level that varies as a function of temperature; and

the temperature sensor is connected to an analog-to-digital converter (“

ADC”

) to generate the signal indicative of the temperature.

22. The device of claim 21 where the ADC is located inside the component package.

23. The device of claim 18 where the temperature sensing device includes a second oscillator that generates a second signal having a second frequency that varies linearly with temperature;

and the device includes a frequency counter to receive the second frequency and output the signal indicative of the temperature.

24. The device of claim 18 where the component package further comprises a parameter memory for storing the plurality of parameters.

25. A system for configuring a oscillator component for generating a temperature corrected frequency, the system comprising:

a temperature sensor and a oscillator circuit included in the oscillator component;

a temperature controlled chamber containing the oscillator component, the temperature controlled chamber controllable to subject the oscillator component to a temperature that varies according to a temperature test profile; and

a temperature correction modeling function coupled to the oscillator component to receive an uncompensated frequency signal and a temperature signal indicative of the temperature of the oscillator component, the temperature correction modeling function operable to model the oscillator component a temperature compensation model associated with a plurality of parameters that characterize the component package, the parameters including dynamic response parameters that characterize a thermal dynamic response of the component package, the temperature compensation modeling function being operable to generate the plurality of parameters.

frequency=(a₀+a₁T+a₂T²+a₃T³+a₄T⁴+ . . . +a_nTⁿ)+{(b_1,0+b_1,1T+b_1,2T²+b_1,3T³+b_1,4T⁴+ . . . +b_1,xT^x)*(b2,0+b_2,1R+ . . . +b_2,yR^y)}+(c₀+c₁T_f+ . . . c_mT_f^m)

where, T=temperature, R=filtered temperature ramp rate, T_f=filtered temperature, and a_n, b_i,x, b_2,y, and c_m are coefficients calculated by curvefitting frequency and temperature data acquired while subjecting the component package to a temperature test profile, the temperature correction modeling function further operable to associate the coefficients to the oscillator component.

26. The system of claim 25 where the temperature compensation model is:

frequency=(a₀+a₁T+a₂T²+a₃T³+a₄T⁴+ . . . +a_nTⁿ)+{(b_1,0+b_1,1T+b_1,2T²+b_1,3T³+b_1,4T⁴+ . . . +b_1,xT^x)*(b2,0+b_2,1R+ . . . +b_2,yR^y)}

where, T=temperature, R=filtered temperature ramp rate, and a_n, b_1,x, b_2,y, are coefficients calculated by curvefitting frequency and temperature data acquired while subjecting the component package to a temperature test profile; and

where the plurality of parameters include the coefficients.

27. The system of claim 25 where the temperature compensation model is:

frequency=(a₀+a₁T+a₂T²+a₃T³+a₄T⁴+ . . . +a_nTⁿ)+{(b_1,0+b_1,1T+b_1,2T²+b_1,3T³+b_1,4T⁴+ . . . +b_1,xT^x)*(b2,0+b_2,1R+ . . . +b_2,yR^y)}+(c₀+c₁T_f+ . . . c_mT_f^m)

where, T=temperature, R=filtered temperature ramp rate, T_f=filtered temperature, and a_n, b_1,x, b_2,y, and c_m are coefficients calculated by curvefitting frequency and temperature data acquired while subjecting the component package to a temperature test profile; and

where the plurality of parameters include the coefficients.