System and method for a mems transducer

Patent metadata

Field	Value
Publication number	US-11225408-B2
Application number	US-202016744857-A
Country	US
Kind code	B2
Filing date	Jan 16, 2020
Priority date	Nov 6, 2013
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

An embodiment as described herein includes a microelectromechanical system (MEMS) with a first MEMS transducer element, a second MEMS transducer element, and a semiconductor substrate. The first and second MEMS transducer elements are disposed at a top surface of the semiconductor substrate and the semiconductor substrate includes a shared cavity acoustically coupled to the first and second MEMS transducer elements.

First claim

What is claimed is:

1. A transducer system comprising:
a first mechanically rigid backplate;
a first deflectable diaphragm adjacent to the first backplate and configured to be electrically coupled to a first bias voltage;
a second mechanically rigid backplate;
a second deflectable diaphragm adjacent to the second backplate and configured to be electrically coupled to a second bias voltage;
an amplifier having input terminals electrically coupled to the first and second mechanically rigid backplates,
a first switch comprising inputs coupled to the first and second bias voltages;
a second switch comprising inputs coupled to the first and second bias voltages;
a first filter directly coupled between an output of the first switch and the first deflectable diaphragm; and
a second filter directly coupled between an output of the second switch and the second deflectable diaphragm.

2. The transducer system of claim 1 , wherein the amplifier has output terminals configured to provide a differential output signal.

3. The transducer system of claim 2 , wherein the amplifier comprises a differential amplifier.

4. The transducer system of claim 1 , further comprising a bias voltage generator configured to generate the first bias voltage and the second bias voltage.

5. The transducer system of claim 4 , wherein the first bias voltage is different from the second bias voltage.

6. The transducer system of claim 4 , wherein the amplifier and the bias voltage generator are disposed on an integrated circuit (IC).

7. The transducer system of claim 1 , wherein the first mechanically rigid backplate and the first deflectable diaphragm comprise a plurality of first mechanically rigid backplates and a plurality of first deflectable diaphragms, and wherein the second mechanically rigid backplate and the second deflectable diaphragm comprise a plurality of second mechanically rigid backplates and a plurality of second deflectable diaphragms.

8. The transducer system of claim 1 , wherein the first and second mechanically rigid backplates comprise a double backplate microelectromechanical system (MEMS) microphone, and wherein the first and second deflectable diaphragms comprise a single diaphragm of the double backplate MEMS microphone.

9. The transducer system of claim 1 , wherein the amplifier comprises a first single ended amplifier and a second single ended amplifier, wherein the first single ended amplifier has a first gain of a substantially equal magnitude and opposite sign as a second gain of the second single ended amplifier.

10. A microelectromechanical system (MEMS) comprising:
a board comprising a first circular cavity disposed above a second circular cavity, the first cavity being larger than the second cavity; and
a MEMS transducer disposed at a top surface of the board adjacent the first cavity, the MEMS transducer comprising:
a semiconductor substrate,
a first MEMS transducer element disposed at a top surface of the semiconductor substrate overlying a third cavity formed in the semiconductor substrate, and
a second MEMS transducer element disposed at the top surface of the semiconductor substrate overlying a fourth cavity formed in the semiconductor substrate, wherein the first, second, third, and fourth cavities are all acoustically coupled;

a first switch comprising inputs coupled to first and second bias voltages;
a second switch comprising inputs coupled to the first and second bias voltages;
a first filter directly coupled between an output of the first switch and a deflectable diaphragm of the first MEMS transducer element; and
a second filter directly coupled between an output of the second switch and a deflectable diaphragm of the second transducer element.

11. The MEMS of claim 10 , wherein the board comprises a first layer comprising the first cavity and a second layer comprising the second cavity.

12. The MEMS of claim 10 , wherein the first and second MEMS transducer elements comprise a double backplate MEMS microphone.

13. The MEMS of claim 10 , wherein the first cavity is wider than the second cavity.

14. The MEMS of claim 10 , wherein the board comprises a printed circuit board (PCB).

15. The MEMS of claim 10 , wherein the board comprises a ceramic substrate.

16. A MEMS transducer system comprising:
a first dual backplate MEMS microphone;
a second dual backplate MEMS microphone;
a first amplifier coupled to the first dual backplate MEMS microphone;
a second amplifier coupled to the second dual backplate MEMS microphone;
a first bias voltage generator configured for selective coupling a first bias voltage to the first dual backplate MEMS microphone or the second dual backplate MEMS microphone;
a second bias voltage generator configured for selective coupling a second bias voltage to the first dual backplate MEMS microphone or the second dual backplate MEMS microphone,
wherein the first bias voltage is different from the second bias voltage;
a first switch comprising inputs coupled to the first and second bias voltage generators, and an output coupled to the first dual backplate MEMS microphone;
a second switch comprising inputs coupled to the first and second bias voltage generators, and an output coupled to the second dual backplate MEMS microphone;
a first filter interposed between the output of the first switch and the first dual backplate MEMS microphone; and
a second filter interposed between the output of the second switch and the second dual backplate MEMS microphone,
wherein an output of the first filter is directly connected to a membrane of the first dual backplate MEMS microphone, and an output of the second filter is directly connected to a membrane of the dual backplate MEMS microphone.

17. The MEMS transducer system of claim 16 , wherein the first amplifier and the second amplifier comprise differential amplifiers.

18. The MEMS transducer system of claim 16 , wherein the first amplifier and the second amplifier comprise single-ended amplifiers.

Assignees

• Infineon Technologies Ag

Inventors

• Wiesbauer Andreas
• Mandl Christian
• Füldner Marc
• Hsu Shu-Ting

Classifications

• H10W90/753

  between laterally-adjacent chips · CPC title

• H10W72/01515

  Forming coatings · CPC title

• H10W72/075

  of bond wires · CPC title

• H10W70/681

  comprising holes not having chips therein, e.g. for outgassing, underfilling or bond wire passage · CPC title

• H04R1/406 Primary

  microphones · CPC title