System comprising a mechanical resonator and method therefor

Patent metadata

Field	Value
Publication number	US-2016102979-A1
Application number	US-201514642202-A
Country	US
Kind code	A1
Filing date	Mar 9, 2015
Priority date	Oct 9, 2014
Publication date	Apr 14, 2016
Grant date	—

Abstract

A system comprises a mechanical resonator; an analog circuit operably coupled to the mechanical resonator; the analog circuit arranged to receive a mechanical resonator measurement signal and to output a mechanical resonator actuation signal to the mechanical resonator; and a digital actuator operably coupled to the analog circuit and configured to provide a frequency sweep of signals to the analog circuit that induces movement of the mechanical resonator.

First claim

1 . A system comprising:
a mechanical resonator; an analog circuit operably coupled to the mechanical resonator; the analog circuit arranged to receive a mechanical resonator measurement signal and to output a mechanical resonator actuation signal to the mechanical resonator; and a digital actuator operably coupled to the analog circuit and configured to provide a frequency sweep of signals to the analog circuit that induces movement of the mechanical resonator.

2 . The system of claim 1 , wherein the digital actuator is configured to provide a frequency sweep of signals to the analog circuit around a natural frequency of the mechanical resonator.

3 . The system of claim 1 , wherein the frequency sweep of signals provided to the analog circuit starts at a frequency higher or lower than the mechanical resonator natural frequency and sweeps towards and beyond said natural frequency.

4 . The system of claim 1 , wherein the frequency sweep of signals provided to the analog circuit comprises a stream of digital pulses close to the resonant frequency of the mechanical resonator.

5 . The system of claim 1 , wherein the frequency sweep of signals provided to the analog circuit provides a kick start to the mechanical resonator from an idle state.

6 . The system of claim 1 , wherein the frequency sweep of signals provided to the analog circuit provides a digital kick start of the mechanical resonator.

7 . The system of claim 1 , wherein the digital actuator is arranged to generate a frequency sweep of signals at least initially in an open loop manner.

8 . The system of claim 7 , wherein the digital actuator comprises an accumulator arranged to accumulate a frequency step size of digital pulses in generating the frequency sweep of signals.

9 . The system of claim 8 , wherein the frequency step size is configurable.

10 . The system of claim 9 wherein the frequency step size is configured to be zero when the mechanical resonator measurement signal input to the analog circuit is determined as being close to the natural frequency of the mechanical resonator.

11 . The system of claim 8 wherein the digital actuator comprises a kick clock period counter operably coupled to the accumulator and arranged to limit a number of digital pulses generated in the open loop manner.

12 . The system of claim 7 , wherein the digital actuator is further arranged to generate a further frequency sweep of signals in a closed loop manner.

13 . The system of claim 12 , wherein the digital actuator further comprises a clock period counter arranged to receive and measure a duration of a mechanical resonator clock signal output by the analog circuit.

14 . The system of claim 8 , wherein the digital actuator further comprises a phase and frequency detector operably coupled to the clock period counter and a kick clock period counter operably coupled to the accumulator and arranged to compare the frequency and phase output of the clock period counter and the kick clock period counter.

15 . The system of claim 14 , wherein the digital actuator further comprises a phase and frequency modulator operably coupled to the phase and frequency detector and arranged to perform at least one from a group of:
update the frequency sweep step size; update a sign associated with the frequency sweep step; stop the frequency sweep when the frequency and phase output of the clock period counter and the kick clock period counter match.

16 . The system of claim 15 wherein the frequency sweep step size is an integer number of a digital master clock period and a fractional number of the mechanical resonator frequency.

17 . The system of claim 1 wherein the system comprises a micro-electro-mechanical system (MEMS) device.

18 . The system of claim 17 wherein the system is a vibrating MEMS (Micro-Electro-Mechanical System) gyroscope and the mechanical resonator is a proof-mass.

19 . An integrated circuit comprising at least one die within a single integrated circuit package, wherein the integrated circuit comprises the digital actuator according to claim 1 .

20 . A method of generating an actuation signal for a mechanical resonator within an micro-electro-mechanical system (MEMS) device, the method comprising:
turning on the MEMS device; providing a frequency sweep of signals to act as a kick start actuation signal for the MEMS device in response to the turn on; and inducing movement of the mechanical resonator in response to the frequency sweep of signals.

Assignees

• Beaulaton Hugues
• Cassagnes Thierry
• Cornibert Laurent
• Wahl Volker
• Freescale Semiconductor Inc

Inventors

• Beaulaton Hugues
• Cassagnes Thierry
• Cornibert Laurent
• Wahl Volker

Classifications

• H01L41/042

  Electricity · mapped topic

• G01C19/5712 Primary

  the devices involving a micromechanical structure · CPC title

• G01C19/5726

  Signal processing · CPC title

• H03B2200/0094

  Measures to ensure starting of oscillations · CPC title

• G01C19/5776 Primary

  Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719 · CPC title