Acoustic sensor resonant peak reduction

Patent metadata

Field	Value
Publication number	US-9414165-B2
Application number	US-201414165430-A
Country	US
Kind code	B2
Filing date	Jan 27, 2014
Priority date	Jan 27, 2014
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

A MEMS acoustic sensor includes a transducer with a frequency response with a gain peak, and a peak reduction circuit with a frequency response and coupled to the transducer. The frequency response of the peak reduction circuit causes attenuation of the gain peak.

First claim

What we claim is:

1. A Micro-Electro-Mechanical Systems (MEMS) acoustic sensor comprising:
a MEMS transducer having a mechanical resonance and having a first frequency response with a gain peak at a resonant frequency of the mechanical resonance; and
a peak reduction circuit with a second frequency response and coupled to the MEMS transducer, wherein the second frequency response of the peak reduction circuit is operable to cause attenuation of the gain peak of the MEMS transducer, and wherein the peak reduction circuit comprises a filter with at least one adjustable parameter operable to compensate for shifts in the gain peak.

2. The MEMS acoustic sensor of claim 1 , wherein the filter comprises one of an analog or digital filter.

3. The MEMS acoustic sensor of claim 2 , wherein the filter is adaptive.

4. The MEMS acoustic sensor of claim 3 , wherein the filter and the MEMS transducer are in multiple packages.

5. The MEMS acoustic sensor of claim 3 , wherein the filter and the MEMS transducer are in a single chip.

6. The MEMS acoustic sensor of claim 2 , wherein the filter is non-adaptive.

7. The MEMS acoustic sensor of claim 6 , wherein the filter and the MEMS transducer are in a single package.

8. The MEMS acoustic sensor of claim 1 , wherein the filter comprises:
a bandpass filter, a stop-band filter, an adaptive filter, or a high-pass filter.

9. The MEMS acoustic sensor of claim 1 , wherein the filter comprises a low pass filter.

10. The MEMS acoustic sensor of claim 1 , wherein the calibration circuit is located in a first chip and the MEMS transducer is located in a second chip.

11. The MEMS acoustic sensor of claim 1 , further comprising a calibrating circuit operable to adjust the at least one adjustable parameter.

12. The MEMS acoustic sensor of claim 1 , wherein calibration circuit is located in a separate package from the MEMS transducer.

13. The MEMS acoustic sensor of claim 1 , further comprising an internal calibration circuit operable to adjust the at least one adjustable parameter.

14. The MEMS acoustic sensor of claim 1 , wherein the peak reduction circuit comprises an active damping circuit.

15. The MEMS acoustic sensor of claim 14 , wherein the active damping circuit is adaptive.

16. The MEMS acoustic sensor of claim 15 , wherein the active damping circuit has at least one parameter, and wherein the MEMS acoustic sensor further comprises a calibration circuit operable to adjust the at least one parameter.

17. The MEMS acoustic sensor of claim 15 , wherein the active damping circuit further includes a feedback loop operable to apply a dampening force to the MEMS transducer to reduce the gain peak.

18. The MEMS acoustic sensor of claim 16 , wherein the calibration circuit is located in one chip and the MEMS transducer is located in another chip.

19. The MEMS acoustic sensor of claim 16 , wherein the calibration circuit is located in a first package and the MEMS transducer is located in a second package.

20. The MEMS acoustic sensor of claim 16 , further comprising an internal calibration circuit operable to adjust the at least one parameter.

21. The MEMS acoustic sensor of claim 1 , wherein the MEMS acoustic sensor is configured as a microphone.

22. A method of attenuating a gain peak of a first frequency response of a Micro-Electro-Mechanical Systems (MEMS) transducer having a mechanical resonance at a gain peak frequency of a MEMS acoustic sensor comprising:
receiving signals from the MEMS transducer at a peak reduction circuit coupled to the MEMS transducer, wherein the peak reduction circuit has a bandwidth and a second frequency response;
adjusting parameters of a filter associated with the peak reduction circuit to compensate for shifts in the gain peak; and
attenuating the gain peak by reducing the bandwidth of the peak reduction circuit below the gain peak frequency of the MEMS transducer.

23. The method of attenuating of claim 22 , wherein adjusting parameters includes adjusting parameters upon a first power-on of the MEMS acoustic sensor.

24. The method of attenuating of claim 23 , wherein adjusting parameters includes adjusting parameters upon a subsequent power-on of the MEMS acoustic sensor.

25. The method of attenuating of claim 22 , wherein adjusting parameters includes continuously adjusting parameters while the MEMS acoustic sensor is powered on.

Assignees

• Invensense Inc

Inventors

• Khenkin Aleksey S
• Cagdaser Baris
• Salvia James Christian
• Assaderaghi Fariborz

Classifications

• H04R19/005

  using semiconductor materials · CPC title

• H04R19/04

  Microphones (H04R19/01 takes precedence) · CPC title

• H04R3/06 Primary

  of electrostatic transducers · CPC title