US-12620385-B2 - Low latency audio processing system having active noise cancellation for ear-worn hearing device

US12620385B2US 12620385 B2US12620385 B2US 12620385B2US-12620385-B2

Abstract

An ear-worn hearing device includes a speaker disposed in a housing comprising a portion configured for wear over, on, or at least partially in a canal of a user's ear. Microphones are integrated with the housing, and a digital signal processing chain is coupled to and located between the microphones and the speaker. The digital signal processing chain includes active noise cancellation (ANC) circuitry configured to generate an anti-noise signal, and speaker-performance-enhancement circuitry coupled to the ANC circuitry and configured to generate a signal based on the anti-noise signal for the speaker. The digital signal processing chain is configured to communicate audio signals between the ANC circuitry and the speaker-performance-enhancement circuitry without changing a format of the audio signals.

Inventors

Thomas E. Miller

Assignees

KNOWLES ELECTRONICS, LLC

Dates

Publication Date: 20260505
Application Date: 20230406

Claims (13)

1 . An ear-worn hearing device comprising: a speaker disposed in a housing comprising a portion configured for wear over, on, or at least partially in a canal of a user's ear; a microphone integrated with the housing; a digital signal processing chain coupled to and located between the microphone and the speaker, the digital signal processing chain comprising: active noise cancellation (ANC) circuitry configured to generate an anti-noise signal based on a microphone signal; and speaker-performance-enhancement circuitry coupled to the ANC circuitry and configured to generate a signal based on the anti-noise signal for the speaker, wherein the digital signal processing chain is configured to communicate audio signals between the ANC circuitry and the speaker-performance-enhancement circuitry without changing a format of the audio signals; and wherein the speaker-performance-enhancement circuitry is pre-distortion circuitry configured to generate a pre-distortion signal based on the anti-noise signal, wherein the ANC circuitry and the pre-distortion circuitry are integrated on a common die.
2 . The ear-worn hearing device of claim 1 , wherein the digital signal processing chain is configured to communicate pulse code modulation format signals between the ANC circuitry and the speaker-performance-enhancement circuitry.
3 . The ear-worn hearing device of claim 1 , further comprising: driver circuitry coupled to and located between the speaker-performance-enhancement circuitry and the speaker; and a digital-to-analog converter coupled to and located between the speaker-performance-enhancement circuitry and the driver circuitry, wherein the driver circuitry applies the signal from the speaker-performance-enhancement circuitry to the speaker.
4 . The ear-worn hearing device of claim 3 , wherein the driver circuitry applies the pre-distortion signal to the speaker.
5 . The ear-worn hearing device of claim 1 , wherein the speaker comprises a microelectromechanical systems (MEMS) speaker.
6 . An integrated circuit for an ear-worn hearing device comprising microphones and a speaker, the integrated circuit comprising: an input signal interface connectable to the microphones when the integrated circuit is assembled with the ear-worn hearing device; an output signal interface connectable to the speaker when the integrated circuit is assembled with the ear-worn hearing device; a digital signal processing chain coupled to the input signal interface and comprising: active noise cancellation (ANC) circuitry configured to generate an anti-noise signal based on feedback and feedforward microphone signals received at the input signal interface; and speaker-performance-enhancement circuitry coupled to and located between the ANC circuitry and the output signal interface, the speaker-performance-enhancement circuitry configured to generate a signal based on the anti-noise signal, wherein the digital signal processing chain is configured to communicate audio signals between the ANC circuitry and the speaker-performance-enhancement circuitry without changing a format of the audio signals, wherein the ANC circuitry and the speaker-performance-enhancement circuitry are integrated on a common die, and wherein the digital signal processing chain is configured to communicate pulse code modulation format signals between the ANC circuitry and the speaker-performance-enhancement circuitry; driver circuitry coupled to and located between the speaker-performance-enhancement circuitry and the output signal interface; and a digital-to-analog converter (DAC) coupled to and located between the speaker-performance-enhancement circuitry and the driver circuit, wherein the driver circuit applies the signal from the speaker-performance-enhancement circuitry to the output signal interface.
7 . The integrated circuit of claim 6 , wherein the DAC and the driver circuitry are integrated on the common die.
8 . The integrated circuit of claim 7 , the speaker-performance-enhancement circuitry is pre-distortion circuitry configured to generate a pre-distortion signal based on the anti-noise signal, wherein the driver circuitry applies the pre-distortion signal to the output signal interface.
9 . The integrated circuit of claim 8 further comprising signal format conversion circuitry coupled to and located between the input signal interface and the ANC circuitry, wherein the signal format conversion circuitry is integrated on the common die.
10 . The integrated circuit of claim 9 in combination with an ear-worn hearing device comprising feedback and feed-forward speakers coupled to the ANC circuitry via the input signal interface, and a microelectromechanical systems (MEMS) speaker coupled to the pre-distortion circuitry via the output signal interface.
11 . An audio processing system having active noise cancellation and pre-distortion, the system comprising: active noise cancellation circuitry and pre-distortion circuitry disposed on a common die, wherein the active noise cancellation circuitry produces pulse code modulated signal output, and the pre-distortion circuitry directly receives the pulse code modulated signal output; a digital to analog converter, wherein the pre-distortion circuitry produces a digital electrical signal output, the digital to analog converter receives the digital electrical signal output, and the digital to analog converter produces a first analog electrical signal output; an amplifier, wherein the amplifier receives the first analog electrical signal output; and a speaker, wherein the amplifier produces a second analog electrical signal output, and the speaker receives the second analog electrical signal output.
12 . The audio processing system of claim 11 , wherein the speaker comprises a microelectromechanical systems (MEMS) speaker.
13 . The audio processing system of claim 11 , further comprising a microphone that outputs a second digital electrical signal output, wherein the active noise circuitry receives the second digital electrical signal output.

Description

FIELD OF THE DISCLOSURE The present disclosure relates generally to an audio signal processing system, and more particularly to reduced latency in an audio signal processing system comprising active noise cancellation for ear-worn hearing devices, and combinations thereof. BACKGROUND Active noise cancellation (ANC) systems in ear-worn hearing devices are known to function optimally when there is little or no latency between audio input and output signals of the ANC system. However, the signal processing architectures of some ear-worn hearing devices have too much latency for effective noise cancellation. The latency in these and other audio systems is attributable to a serial processing of the audio signal. In one such hearing device, the signal processor comprises ANC circuitry combined with pre-distortion circuitry that compensates for non-linearity in a transfer characteristic of the speaker. The non-linearity may be inherent or result from driving the speaker beyond its linear operating range. Pre-distortion generally improves sound quality for a given level of sound output and can compensate for non-linearity in microelectromechanical systems (MEMS) and other speakers. Improved linearity can improve ANC performance. In other applications, latency can be attributable to the ANC circuit combined with other circuits that improve speaker performance. Thus, there is an ongoing need for latency improvements in audio signal processing systems suitable for ear-worn hearing devices and other applications. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is schematic block diagram of an exemplary prior art ANC system. FIG. 2 is a schematic block diagram of a representative audio processing system according to the present disclosure. FIG. 3 is a schematic diagram of a representative ear-worn hearing device shown inserted into a user's ear. FIG. 4 is a schematic block diagram of a representative digital signal processing chain illustrated as part of an integrated circuit. FIG. 5 is a schematic block diagram of another representative digital signal processing chain illustrated as part of an integrated circuit. Those of ordinary skill in the art will appreciate that elements in the figures are illustrated for simplicity and clarity. It will be appreciated further that certain actions and/or steps may be described or depicted in a particular order of occurrence while those having ordinary skill in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein. DETAILED DESCRIPTION According to an aspect of the disclosure, an ear-worn hearing device comprises a speaker disposed in a housing comprising a portion configured for wear over, on, or at least partially in a canal of a user's ear. In an embodiment microphones are integrated with the housing, and a digital signal processing chain is coupled to and located between the microphones and the speaker. In an embodiment the digital signal processing chain comprises active noise cancellation (ANC) circuitry configured to generate an anti-noise signal, and speaker-performance-enhancement circuitry coupled to the ANC circuitry and configured to generate a signal based on the anti-noise signal for the speaker, wherein the digital signal processing chain is configured to communicate audio signals between the ANC circuitry and the speaker-performance-enhancement circuitry without changing a format of the audio signals. In an embodiment the digital signal processing chain is configured to communicate pulse code modulation format signals, among others, between the ANC circuitry and the speaker-performance-enhancement circuitry. In an embodiment the ANC circuitry and the speaker-performance-enhancement circuitry are integrated on a common die. In an embodiment the ear-worn hearing device further comprises driver circuitry coupled to and located between the speaker-performance-enhancement circuitry and the speaker, and a digital-to-analog converter coupled to and located between the speaker-performance-enhancement circuitry and the driver circuitry, wherein the driver circuitry applies the signal from the speaker-performance-enhancement circuitry to the speaker. In an embodiment the speaker-performance-enhancement circuitry is pre-distortion circuitry configured to generate a pre-distortion signal based on an anti-noise signal, wherein the driver circuitry applies the pre-distortion signal to the speaker. In an embodiment the speaker-performance-enhancement circuitry is pre-distortion circuitry configured to generate a pre-distortion signal based on the anti-noise signal, wherein the ANC circuitry and the pre-distortion circuitry are integrated on a common die. In an embodim