Method and apparatus for generating a proof-mass drive signal

• US 9,503,295 B2
• Filed: 11/06/2012
• Issued: 11/22/2016
• Est. Priority Date: 11/06/2012
• Status: Expired due to Fees

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Cornibert, Laurent, Beaulaton, Hugues, Cassagnes, Thierry, Trauth, Gerhard
• Primary Examiner(s): SHAH, TANMAY K
• Application Number:
  US14/440,187
• Publication Number:
  US 20150280949A1
• Time in Patent Office: 1,477 Days
• Field of Search: 340/1.1
• US Class Current: 1/1
• CPC Class Codes: G01C 19/5726 Signal processing
• CPC Class Codes: H04L 27/04 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/125 using a controlled oscillator in an open loop

Abstract

A drive-mode oscillator module generates at least one proof-mass drive signal for use within a micro-electro-mechanical system (MEMS) device. The drive-mode oscillator module comprises at least one gain control component arranged to receive at least one proof-mass motion measurement signal, and to generate a digital modulation control signal based at least partly on the at least one proof-mass motion measurement signal, and at least one modulation component arranged to receive the digital amplitude modulation control signal, and to output at least one proof-mass drive signal. The at least one modulation component is arranged to digitally modulate the at least one proof-mass drive signal based at least partly on the received digital amplitude modulation control signal.

Claims

1. A drive-mode oscillator module for generating at least one proof-mass drive signal for use within a micro-electro-mechanical system (MEMS) device, the drive-mode oscillator module comprising:

at least one gain control component arranged to receive at least one proof-mass motion measurement signal, receive at least one reference amplitude signal, compare the at least one proof-mass motion measurement signal to the at least one reference amplitude signal, generate a digital modulation control signal based at least partly on the at least one proof-mass motion measurement signal, and output the digital modulation control signal comprising an indication of whether the at least one proof-mass motion measurement signal exceeds the at least one reference amplitude signal; and

at least one modulation component arranged to receive the digital modulation control signal, and to output at least one proof-mass drive signal, wherein the at least one modulation component is arranged to digitally modulate the at least one proof-mass drive signal based at least partly on the received digital modulation control signal.

7. The drive-mode oscillator module of claim 1, wherein the modulation component is arranged to apply amplitude shift keying (ASK) modulation to the at least one proof-mass drive signal based at least partly on the received digital modulation control signal.

8. The drive-mode oscillator module of claim 7, wherein the modulation component is arranged to:

output a 90°

phase shifted oscillating proof-mass drive signal upon the digital modulation control signal comprising an indication that the at least one proof-mass motion measurement signal is less than the at least one reference amplitude signal; and

output a constant voltage proof-mass drive signal upon the digital modulation control signal comprising an indication that the at least one proof-mass motion measurement signal exceeds the at least one reference amplitude signal.

9. The drive-mode oscillator module of claim 1, wherein the modulation component is arranged to apply binary phase shift keying (BPSK) modulation to the at least one proof-mass drive signal based at least partly on the received digital modulation control signal.

10. The drive-mode oscillator module of claim 9, wherein the modulation component is arranged to:

output a 90°

phase shifted oscillating proof-mass drive signal upon the digital modulation control signal comprising an indication that the at least one proof-mass motion measurement signal is less than the at least one reference amplitude signal; and

output an inverted form of the 90°

phase shifted oscillating proof-mass drive signal upon the digital modulation control signal comprising an indication that the at least one proof-mass motion measurement signal exceeds the at least one reference amplitude signal.

11. The drive-mode oscillator module of claim 1, wherein the drive-mode oscillator module further comprises at least one analogue start-up component selectively arranged to generate a proof-mass drive signal for driving a proof-mass of the MEMS device during a start-up phase of the MEMS device.

13. The drive-mode oscillator module of claim 1, wherein the drive-mode oscillator module comprises at least one capacitance to voltage component arranged to receive a signal comprising an indication of a capacitance change of a MEMS drive measurement unit (DMU) and to convert the received indication of a capacitance change to the proof-mass motion measurement signal.

14. The drive-mode oscillator module of claim 1 implemented within an integrated circuit device comprising at least one die within a single integrated circuit package.

15. A micro-electro-mechanical system (MEMS) device comprising at least one drive-mode oscillator module according to claim 1.

2. A drive-mode oscillator module for generating at least one proof-mass drive signal for use within a micro-electro-mechanical system (MEMS) device, the drive-mode oscillator module comprising:

at least one gain control component arranged to receive at least one proof-mass motion measurement signal, and to generate a digital modulation control signal based at least partly on the at least one proof-mass motion measurement signal;

at least one modulation component arranged to receive the digital modulation control signal, and to output at least one proof-mass drive signal, wherein the at least one modulation component is arranged to digitally modulate the at least one proof-mass drive signal based at least partly on the received digital modulation control signal; and

at least one phase component arranged to;

receive the at least one proof-mass motion measurement signal;

detect a proof-mass motion phase; and

output to the at least one modulation component a digital phase signal,

wherein the at least one modulation component is further arranged to output the at least one proof-mass drive signal comprising a phase based at least partly on the received digital phase signal output by the at least one phase component.

3. The drive-mode oscillator module of claim 2, wherein the at least one phase component is arranged to output the digital phase signal comprising a 90°

phase shift relative to the detected proof-mass motion phase.

4. The drive-mode oscillator module of claim 3, wherein the at least one phase component comprises a comparator arranged to:

receive a differential proof-mass motion measurement signal;

compare a first differential component of the differential proof-mass motion measurement signal to a second differential component of the differential proof-mass motion measurement signal; and

output a phase detection signal based at least partly on the comparison of the first and second differential components of the differential proof-mass motion measurement signal, wherein the phase component further comprises a phase shift component arranged to;

receive the phase detection signal output by the comparator;

apply a 90°

phase shift to the phase detection signal; and

output the digital phase signal comprising the phase shifted phase detection signal.

5. The drive-mode oscillator module of claim 2, wherein the modulation component comprises at least one level shifter arranged to receive the digital phase signal output by the at least one phase component, apply a voltage level shift to the received digital phase signal, and to output at least one proof-mass drive signal based at least partly on the level shifted digital phase signal.

6. The drive-mode oscillator module of claim 5, wherein the at least one level shifter is configurable to apply a configurable voltage level shift to the received digital phase signal.

12. A drive-mode oscillator module for generating at least one proof-mass drive signal for use within a micro-electro-mechanical system (MEMS) device, the drive-mode oscillator module comprising:

at least one gain control component arranged to receive at least one proof-mass motion measurement signal, and to generate a digital modulation control signal based at least partly on the at least one proof-mass motion measurement signal;

at least one modulation component arranged to receive the digital modulation control signal, and to output at least one proof-mass drive signal, wherein the at least one modulation component is arranged to digitally modulate the at least one proof-mass drive signal based at least partly on the received digital modulation control signal; and

at least one analogue start-up component selectively arranged to generate a proof-mass drive signal for driving a proof-mass of the MEMS device during a start-up phase of the MEMS device, wherein the at least one analogue start-up component comprises;

an integrator component arranged to receive the at least one proof-mass motion measurement signal and apply a 90°

phase shift thereto; and

an amplifier component arranged to receive the phase shifted proof-mass motion measurement signal, and to output a proof-mass drive signal based at least partly on the phase shifted proof-mass motion measurement signal.