Clock generator with dual-path temperature compensation

1. A timing signal generator comprising:

a resonator;

one or more temperature-sense circuits to generate an analog temperature signal and a digital temperature signal indicative of temperature of the resonator;

first and second temperature compensation signal generators to generate, respectively, an analog temperature compensation signal according to the analog temperature signal and a digital temperature compensation signal according to the digital temperature signal; and

clock generating circuitry to drive the resonator into mechanically resonant motion and to generate a temperature-compensated output timing signal based on the mechanically resonant motion, the analog temperature compensation signal and the digital temperature compensation signal;

wherein the clock generating circuitry comprises a phase-locked loop (PLL), and wherein an element within the phase-locked loop is to be varied in a manner dependent on the digital temperature compensation signal to shift operation of the PLL, and correspondingly vary the temperature-compensated output timing signal.

2. The timing signal generator of claim 1 wherein the resonator exhibits a natural resonant frequency having linear and nonlinear temperature dependence, and wherein the clock generating circuitry to generate the temperature-compensated output timing signal predominantly compensates for the linear temperature dependence based on the analog temperature compensation signal.

3. The timing signal generator of claim 2 wherein the timing signal generator compensates the nonlinear temperature dependence based at least in part on the digital temperature compensation signal.

4. The timing signal generator of claim 1 wherein the resonator exhibits a temperature-dependent natural resonant frequency, and wherein the clock generating circuitry to generate the temperature-compensated output timing signal implements a coarse compensation for the temperature-dependence of the natural frequency based on the analog temperature compensation signal and implements a fine compensation for the temperature-dependence of the natural frequency based on the digital temperature compensation signal.

5. The timing signal generator of claim 1 wherein the one or more temperature-sense circuits comprises at least one of (i) a temperature-to-analog converter to generate the analog temperature signal and a temperature-to-digital converter to generate the digital temperature signal independently of the analog temperature signal, (ii) a temperature-to-analog converter to generate the analog temperature signal and an analog-to-digital converter to generate the digital temperature signal based on the analog temperature signal, or (iii) a temperature-to-digital converter to generate the digital temperature signal and a digital-to-analog converter to generate the analog temperature signal based on digital temperature signal.

6. The timing signal generator of claim 1 wherein the resonator comprises a microelectromechanical system (MEMS) resonant member implemented in a first semiconductor die and the clock generating circuit is implemented at least in part in a second semiconductor die.

7. The timing signal generator of claim 6 wherein the one or more temperature-sense circuits comprise at least one of a MEMS thermistor implemented in the first semiconductor die or an additional MEMS resonant member implemented in the first semiconductor die.

8. The timing signal generator of claim 1 wherein the clock generating circuitry to drive the resonator into mechanically resonant motion and to generate the temperature-compensated output timing signal comprises a first frequency compensation circuit to frequency-adjust the temperature-compensated output timing signal, the first frequency compensation circuit having a first circuit element to which at least the analog temperature compensation signal is applied to effect at least one of a capacitance of the first circuit element within a continuous capacitance range or a propagation delay through the first circuit element within a continuously variable propagation-delay range.

9. The timing signal generator of claim 1 wherein the analog temperature compensation signal is applied at a first output timing signal correction point, outside of the PLL, to continuously vary timing provided by the temperature-compensated output timing signal, and wherein the element within the PLL represents a second output timing signal correction point, inside of the PLL.

10. The timing signal generator of claim 1 wherein the analog temperature compensation signal is to be applied to control a continuously variable capacitance or delay element within the PLL, to shift operation of the PLL.

11. A method of operation within a timing signal generator having a resonator:

generating an analog temperature signal and a digital temperature signal indicative of temperature of the resonator;

generating an analog temperature compensation signal according to the analog temperature signal and a digital temperature compensation signal according to the digital temperature signal;

driving the resonator into mechanically resonant motion; and

generating a temperature-compensated output timing signal based on the mechanically resonant motion, the analog temperature compensation signal and the digital temperature compensation signal;

wherein generating the temperature-compensated output timing signal comprises varying an element without a phase-locked loop (PLL) in a manner dependent on the digital temperature compensation signal, so as to shift operation of the PLL and correspondingly vary the temperature-compensated output timing signal.

12. The method of claim 11 wherein the resonator exhibits a natural resonant frequency having linear and nonlinear temperature dependence, and wherein generating the temperature-compensated output timing signal comprises compensating for the linear temperature dependence based predominantly on the analog temperature compensation signal.

13. The method of claim 12 wherein further comprising compensating for the nonlinear temperature dependence based at least in part on the digital temperature compensation signal.

14. The method of claim 11 wherein the resonator exhibits a temperature-dependent natural resonant frequency, and wherein generating the temperature-compensated output timing signal comprises coarsely compensating for the temperature-dependence of the natural frequency based on the analog temperature compensation signal and finely compensating for the temperature-dependence of the natural frequency based on the digital temperature compensation signal.

15. The method of claim 11 wherein generating the analog temperature signal and the digital temperature signal comprises at least one of (i) generating the analog temperature signal within a temperature-to-analog converter and independently generating the digital temperature signal within a temperature-to-digital converter, (ii) generating the analog temperature signal within a temperature-to-analog converter and performing analog-to-digital conversion of the analog temperature signal to yield the digital temperature signal, or (iii) generating the digital temperature signal within a temperature-to-digital converter and performing digital-to-analog conversion of the digital temperature signal to yield the analog temperature signal.

16. The method of claim 11 wherein the resonator comprises a microelectromechanical system (MEMS) resonant member implemented in a first semiconductor die and wherein generating the analog temperature signal and the digital temperature signal indicative of temperature of the resonator comprises generating one or more of the analog temperature and the digital temperature based at least in part on resistance of a MEMS thermistor implemented in the first semiconductor die.

17. The method of claim 11 wherein:

the resonator comprises a first microelectromechanical system (MEMS) resonant member implemented in a first semiconductor die;

a second MEMS resonant member is also implemented in the first semiconductor die; and

generating the analog temperature signal and the digital temperature signal indicative of temperature of the resonator comprises generating one or more of the analog temperature and the digital temperature based at least in part on comparison of frequencies of the first and second MEMS resonant members.

18. The method of claim 11 wherein generating the temperature-compensated output timing signal comprises applying at least the analog temperature compensation signal to a first circuit element within a frequency compensation circuit to effect at least one of a capacitance of the first circuit element within a continuous capacitance range or a propagation delay through the first circuit element within a continuously variable propagation-delay range.

19. The method of claim 11 wherein the method further comprises applying the analog temperature compensation signal at a first output timing signal correction point, outside of the PLL, to continuously vary timing provided by the temperature-compensated output timing signal, and wherein the element within the PLL represents a second output timing signal correction point, inside of the PLL.

20. The method of claim 11 further comprising using the analog temperature compensation signal to control a continuously variable capacitance or delay element within the PLL, to shift operation of the PLL.

21. A timing signal generator comprising:

a resonator;

means for generating an analog temperature signal and a digital temperature signal indicative of temperature of the resonator;

means for generating an analog temperature compensation signal according to the analog temperature signal and a digital temperature compensation signal according to the digital temperature signal;

means for driving the resonator into mechanically resonant motion; and

means for generating a temperature-compensated output timing signal based on the mechanically resonant motion, the analog temperature compensation signal and the digital temperature compensation signal;

wherein the means for generating the temperature-compensated output timing signal comprises means for varying an element within a phase-locked loop (PLL) manner dependent on the digital temperature compensation signal, to shift operation of the PLL and correspondingly vary the temperature-compensated output timing signal.