Shock Recovery for Silicon Microphone Systems

Patent metadata

Field	Value
Publication number	US-2023121912-A1
Application number	US-202117451562-A
Country	US
Kind code	A1
Filing date	Oct 20, 2021
Priority date	Oct 20, 2021
Publication date	Apr 20, 2023
Grant date	—

Abstract

A microphone includes an amplifier coupled to an input node of the microphone; a shock detector coupled to the input node of the microphone; and a recovery circuit having an input coupled to an output of the shock detector, and an output coupled to the input of the microphone.

First claim

What is claimed is:

1 . A microphone comprising:
an amplifier coupled to an input node of the microphone; a shock detector coupled to the input node of the microphone; and a recovery circuit having an input coupled to an output of the shock detector, and an output coupled to the input of the microphone.

2 . The microphone of claim 1 , wherein the shock detector comprises a plurality of comparators.

3 . The microphone of claim 1 , wherein the recovery circuit comprises:
a digital-to-analog converter (DAC); and a switch having a control node coupled to an output of the DAC.

4 . The microphone of claim 3 , wherein the recovery circuit further comprises a counter and a state machine.

5 . The microphone of claim 3 , wherein a controlled node of the switch is configured for supplying a plurality of impedance steps to the input node of the microphone.

6 . The microphone of claim 3 , wherein a plurality of voltage steps at the control node of the switch is configured to have a range between a shocked bias level and a normal bias level.

7 . The microphone of claim 3 , further comprising an additional switch coupled to the input node of the microphone, wherein the additional switch is configured for implementing a startup mode of operation.

8 . A circuit comprising:
a shock detector coupled to an input node; and a recovery circuit coupled to an output of the shock detector, wherein the recovery circuit is configured for lowering an impedance of the input node after a shock, and then gradually increasing the impedance of the input node.

9 . The circuit of claim 8 , wherein the shock detector comprises a first comparator having a first threshold voltage, and a second comparator having a second threshold voltage.

10 . The circuit of claim 8 , wherein the recovery circuit comprises:
a digital-to-analog converter (DAC) coupled to an output of the recovery circuit; and a switch having a control node coupled to an output of the DAC, and a controlled node coupled to an output of the recovery circuit.

11 . The circuit of claim 10 , wherein the recovery circuit further comprises a counter and a state machine.

12 . The circuit of claim 10 , wherein the controlled node of the switch is configured for supplying a plurality of sequentially increased impedance steps to the input node.

13 . The circuit of claim 12 , wherein the sequentially increased impedance steps are configured to have a range between a shocked bias level and a normal bias level.

14 . The circuit of claim 10 , wherein the switch is coupled between the input node and a bias voltage source.

15 . A method of operating a microphone, the method comprising:
detecting a shock condition at an input of the microphone; reducing an impedance of a bias circuit coupled to the input of the microphone upon detection of the shock condition; and gradually increasing the impedance of the bias circuit.

16 . The method of claim 15 , wherein the impedance of the bias circuit is gradually increased after the shock condition terminates.

17 . The method of claim 15 , wherein the impedance of the bias circuit is gradually increased with a predetermined sequence of impedance steps.

18 . The method of claim 15 , wherein gradually increasing the impedance comprises controlling a switch coupled to the input.

19 . The method of claim 18 , wherein controlling the switch comprises applying a predetermined sequence of voltage steps to a gate of the switch.

20 . The method of claim 19 , wherein the predetermined sequence of voltage steps is provided by a digital-to-analog converter (DAC).

Assignees

• Infineon Technologies Ag

Inventors

• Ceballos Jose Luis
• Chen Hong
• Ciciotti Fulvio
• Wiesbauer Andreas
• Wotruba Bernhard

Classifications

• H04R19/04 Primary

  Microphones (H04R19/01 takes precedence) · CPC title

• H04R2307/023

  Diaphragms comprising ceramic-like materials, e.g. pure ceramic, glass, boride, nitride, carbide, mica and carbon materials · CPC title

• H04R2201/003

  Mems transducers or their use · CPC title

• H04R2499/11

  Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's · CPC title

• H04R19/016

  for microphones · CPC title