Low power always-on microphone using power reduction techniques

Patent metadata

Field	Value
Publication number	US-10892772-B2
Application number	US-201916541869-A
Country	US
Kind code	B2
Filing date	Aug 15, 2019
Priority date	Aug 17, 2018
Publication date	Jan 12, 2021
Grant date	Jan 12, 2021

Abstract

An audio activity detector device is disclosed. The audio activity detector device comprises a closed loop feedback regulating circuit that supplies an input signal representative of a time-varying voltage signal to a quantizer circuit, wherein the quantizer circuit, as a function of the input signal, converts the input signal to a quantizer discrete-time signal; a first circuit that, as a function of the discrete-time signal, determines a key quantizer statistic value for the quantizer discrete-time signal; and a second circuit that, as a function of the key quantizer statistic value, determines a signal statistic value for the input signal and a gain control value.

First claim

What is claimed is:

1. A device comprising:
a closed loop feedback regulating circuit that supplies an input signal representative of a time-varying voltage signal to a quantizer circuit, wherein the quantizer circuit, as a function of the input signal, converts the input signal to a quantizer discrete-time signal;
a first circuit that, as a function of the discrete-time signal, determines a key quantizer statistic value for the quantizer discrete-time signal; and
a second circuit that, as a function of the key quantizer statistic value, determines a signal statistic value for the input signal and a gain control value.

2. The device of claim 1 , wherein the key quantizer statistic value represents a root mean square value.

3. The device of claim 1 , wherein the key quantizer statistic value represents a standard deviation value.

4. The device of claim 1 , wherein the key quantizer statistic value represents a peak-to-peak value.

5. The device of claim 1 , wherein the key quantizer statistic value represents an instantaneous amplitude value.

6. The device of claim 1 , wherein the key quantizer statistic value represents the input signal.

7. The device of claim 1 , wherein the first circuit determines the key quantizer statistic value based on the discrete-time signal and a system clock value.

8. The device of claim 1 , wherein the second circuit determines the signal statistic value and the gain control value based on the key quantizer statistic value and a system clock value.

9. The device of claim 1 , wherein the gain control value is supplied to the closed loop feedback regulating circuit.

10. The device of claim 1 , wherein the input signal is a first input signal, and wherein the closed loop feedback regulating circuit receives a second input signal representative of an unregulated signal of varying signal amplitudes.

11. The device of claim 1 , wherein the quantizer circuit is a multi-bit quantizer circuit.

12. The device of claim 1 , wherein the gain control value is dithered using delta-sigma dithering.

13. A method, comprising:
converting, by a device comprising an electronic circuit, a time-varying voltage signal to a discrete-time signal;
determining, by the device, a quantizer statistic value based on the discrete-time signal; and
determining, by the device, a signal statistic value for the time-varying voltage signal as a function of the quantizer statistic value and a gain control value as a function of the quantizer statistic value.

14. The method of claim 13 , wherein the electronic circuit is a multi-bit quantizer circuit.

15. The method of claim 13 , wherein the quantizer statistic value represents an instantaneous amplitude value.

16. The method of claim 13 , further comprising determining, by the device, the quantizer statistic value as a function of the discrete-time signal and a clock signal value.

17. The method of claim 13 , further comprising determining, by the device, the signal statistic value and the gain control value as a function of the quantizer statistic value and a clock signal value.

Assignees

• Invensense Inc

Inventors

• Perrott Michael

Classifications

• H03M3/416 Primary

  all these quantisers being multiple bit quantisers · CPC title

• G06F1/3206 Primary

  Monitoring of events, devices or parameters that trigger a change in power modality · CPC title

• H04W52/0251

  using monitoring of local events, e.g. events related to user activity · CPC title

• H04R3/00

  Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) · CPC title

• G10L25/84

  for discriminating voice from noise · CPC title