Sensor with movable part and biasing

• US 9,525,925 B2
• Filed: 02/25/2011
• Issued: 12/20/2016
• Est. Priority Date: 02/25/2011
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Wurzinger, Christoph Bernhard, Ceballos, Jose Luis
• Primary Examiner(s): Martin, Laura
• Assistant Examiner(s): Shah, Samir M
• Application Number:
  US13/035,896
• Publication Number:
  US 20120217171A1
• Time in Patent Office: 2,125 Days
• Field of Search: 204/406, 204/409
• US Class Current: 1/1
• CPC Class Codes: G01C 19/5776 Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: H03F 2200/03 the amplifier being designed for audio applications
• CPC Class Codes: H03F 2203/45112 the biasing of the differential amplifier being controlled from the input or the output signal
• CPC Class Codes: H03F 2203/45116 Feedback coupled to the input of the differential amplifier
• CPC Class Codes: H03F 2203/45544 the IC comprising one or more capacitors, e.g. coupling capacitors
• CPC Class Codes: H03F 3/183 with semiconductor devices only
• CPC Class Codes: H03F 3/45071 with semiconductor devices only
• CPC Class Codes: H04R 1/04 Structural association of microphone with electric circuitry therefor in deaf-aid sets H04R25/00
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

Methods and apparatuses are provided wherein a sensor which comprises at least two electrodes and a movable part is alternately biased with at least two different voltages.

Claims

1. An apparatus, comprising:

a sensor comprising a movable part and at least two electrodes; and

biasing circuitry configured to alternately apply at least one first voltage and at least one second voltage to the at least two electrodes, the first voltage having a magnitude being different than a magnitude of the second voltage.

2. The apparatus of claim 1, wherein applying said at least one first voltage is associated with a stable state of said movable part and applying said at least one second voltage is associated with an unstable state of said movable part.

3. The apparatus of claim 1, further comprising a feedback path from an output of said sensor to said biasing circuitry, said biasing circuitry being configured to provide said at least one first voltage and said at least one second voltage depending on a signal received via said feedback path.

4. The apparatus of claim 1, wherein said sensor comprises at least one of a microphone, an accelerometer, or a gyroscope.

5. The apparatus of claim 1, wherein said sensor is implemented as a microelectromechanical system.

6. The apparatus of claim 1, wherein said at least two electrodes comprise a first plate and a second plate, and wherein said movable part comprises a membrane suspended between said first plate and said second plate.

7. A method, comprising:

providing a sensor comprising a movable part arranged between at least two electrodes, and

alternately switching a first biasing voltage, applied directly to said movable part, between at least two different values, or alternately switching a second biasing voltage, applied to at least one electrode, of the at least two electrodes associated with said movable part, between at least two different values.

8. The method of claim 7, wherein said switching of said first biasing voltage or said second biasing voltage comprises switching said sensor between a stable state and an unstable state.

9. The method of claim 7, further comprising providing said first biasing voltage or said second biasing voltage based on an output of said sensor.

10. The method of claim 7, further comprising,

generating a first feedback signal based on a first amplification of an output of said sensor;

and

generating a second feedback signal based on a second amplification of said output of said sensor,

said second amplification being different from said first amplification.

11. The method of claim 7, wherein said sensor comprises at least one of a microphone, an accelerometer, or a gyroscope.