System and method for a mems transducer

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.