Sensor with movable parts and biasing

• US 10,194,250 B2
• Filed: 12/19/2016
• Issued: 01/29/2019
• 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): West, Paul
• Assistant Examiner(s): Shabman, Mark A
• Application Number:
  US15/383,543
• Publication Number:
  US 20170099549A1
• Time in Patent Office: 771 Days
• 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 first electrode, a movable part, and a second electrode,

a first capacitance being defined between the first electrode and the movable part,

a second capacitance being defined between the movable part and the second electrode,

the first electrode being directly coupled to an amplifier, and

the second electrode being directly coupled to the amplifier;

a first switch coupling a first voltage source with;

the movable part, or

the first electrode and the second electrode;

a second switch coupling a second voltage source with;

the movable part, or

the first electrode and the second electrode; and

a clock, coupled to the first switch and the second switch, to alternately close the first switch and the second switch.

2. The apparatus of claim 1, further comprising:

the amplifier,

a first input of the amplifier being coupled to the first electrode,

a second input of the amplifier being coupled to the second electrode,

a first output of the amplifier being coupled to a first output pin, and

a second output of the amplifier being coupled to a second output pin.

3. The apparatus of claim 1, further comprising:

at least one third switch coupled in parallel to the amplifier,

the at least one third switch to operate synchronously with the second switch.

4. The apparatus of claim 1, further comprising:

at least one third capacitance coupled in parallel with the amplifier.

5. The apparatus of claim 1, further comprising:

biasing circuitry coupled with the first electrode and the second electrode.

6. The apparatus of claim 1, wherein a voltage of the first voltage source is associated with a stable state of the movable part, and a voltage of the second voltage source is associated with an unstable state of the movable part.

7. The apparatus of claim 1, wherein the first electrode comprises a first plate, the second electrode comprises a second plate, and the movable part comprises a membrane suspended between the first plate and the second plate.

8. A method, comprising:

receiving, by an apparatus, a first voltage from a first voltage source,

the apparatus comprising a sensor that comprises a first electrode, a movable part, and a second electrode,

a first capacitance being defined between the first electrode and the movable part,

a second capacitance being defined between the movable part and the second electrode,

the first electrode being directly coupled to an amplifier, and

the second electrode being directly coupled to the amplifier;

receiving, by the apparatus, a second voltage from a second voltage source; and

alternately closing, by the apparatus and based on a clock, a first switch and a second switch,

the first voltage source being coupled, via the first switch, with;

the movable part, or

the first electrode and the second electrode, and

the second voltage source being coupled, via the second switch, with;

the movable part, or

the first electrode and the second electrode.

9. The method of claim 8, wherein a first input of the amplifier is coupled to the first electrode,

where a second input of the amplifier is coupled to the second electrode,

where a first output of the amplifier is coupled to a first output pin, and

where a second output of the amplifier is coupled to a second output pin.

10. The method of claim 8, wherein at least one third switch is coupled in parallel to the amplifier,

the at least one third switch to operate synchronously with the second switch.

11. The method of claim 8, wherein at least one third capacitance is coupled in parallel with the amplifier.

12. The method of claim 8, wherein biasing circuitry is coupled with the first electrode and the second electrode.

13. The method of claim 8, wherein the first voltage of the first voltage source is associated with a stable state of the movable part, and the second voltage of the second voltage source is associated with an unstable state of the movable part.

14. The method of claim 8, wherein a membrane, of the movable part, is suspended between a first plate of the first electrode and a second plate of the second electrode.

15. An apparatus, comprising:

a first electrode;

a movable part; and

a second electrode,

a first capacitance being defined between the first electrode and the movable part,

a second capacitance being defined between the movable part and the second electrode,

the first electrode being directly coupled to an amplifier,

the second electrode being directly coupled to the amplifier,

the movable part being alternately coupled, based on a clock and via a first switch and a second switch, to a first voltage source and a second voltage source,

the movable part being coupled the first voltage source when the first switch is closed, and

the movable part being coupled to the second voltage source when the second switch is closed.

16. The apparatus of claim 15, wherein a first input of the amplifier is coupled to the first electrode, and

where a second input of the amplifier is coupled to the second electrode,

where a first output of the amplifier is coupled to a first output pin, and

where a second output of the amplifier is coupled to a second output pin.

17. The apparatus of claim 15, wherein at least one third switch is coupled in parallel to the amplifier,

the at least one third switch to operate synchronously with the second switch.

18. The apparatus of claim 15, wherein at least one third capacitance is coupled in parallel with the amplifier.

19. The apparatus of claim 15, wherein biasing circuitry is coupled with the first electrode and the second electrode.

20. The apparatus of claim 15, wherein a voltage of the first voltage source is associated with a stable state of the movable part, and a voltage of the second voltage source is associated with an unstable state of the movable part.