Hearing device comprising an anti-feedback power down detector

Patent metadata

Field	Value
Publication number	US-9769574-B2
Application number	US-201615052308-A
Country	US
Kind code	B2
Filing date	Feb 24, 2016
Priority date	Feb 24, 2015
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

The application relates to a hearing device comprising a) a forward path between an input transducer for converting an input sound to an electric input signal and an output transducer for converting an electric output signal to an output sound, the forward path comprising a signal processing unit for applying a level and/or frequency dependent gain to the electric input signal or a signal originating therefrom and for providing a processed signal, and feeding the processed signal or a signal originating therefrom to the output transducer, an acoustic feedback path being defined from said output transducer to said input transducer; b) a configurable anti-feedback system comprising a feedback estimation unit for providing an estimate of said acoustic feedback path; c) a number of detectors, each providing a detector signal for characterizing a signal of the forward path. The object of the present application is to save power in a hearing device. The problem is solved in that the hearing device further comprises an activation control unit configured to control the anti-feedback system based on said detector signals, and to bring the anti-feedback system into one of at least two predefined modes based on said detector signals, said at least two predefined modes comprising an ON-mode and an OFF-mode. The invention may e.g. be used in hearing aids, headsets, ear phones, active ear protection systems, or similar portable devices, where a need for feedback cancellation and low power consumption is important.

First claim

The invention claimed is:

1. A hearing device comprising
a forward path between an input transducer for converting an input sound to an electric input signal and an output transducer for converting an electric output signal to an output sound, the forward path comprising a signal processing unit for applying a level and/or frequency dependent gain to the electric input signal or a signal originating therefrom and for providing a processed signal, and feeding the processed signal or a signal originating therefrom to the output transducer, an acoustic feedback path being defined from said output transducer to said input transducer;
a configurable anti-feedback system comprising a feedback estimation unit for providing an estimate of said acoustic feedback path, wherein the feedback estimation unit comprises an update part implementing an adaptive algorithm and a variable filter part for filtering an input signal according to variable filter coefficients determined by said adaptive algorithm;
a number of detectors, each providing a detector signal for characterizing a signal of the forward path;

wherein
the hearing device further comprises an activation control unit configured to control the anti-feedback system based on said detector signals, and to bring the anti-feedback system into one of at least two predefined modes based on said detector signals, said at least two predefined modes comprising an ON-mode and an OFF-mode, and to allow operation of the anti-feedback system in a number of different ON-modes, including a maximum power consumption ON-mode, and wherein the update part of the feedback estimation unit is configured to update said filter coefficients of the variable filter part with a configurable update frequency.

2. A hearing device according to claim 1 wherein the anti-feedback system is operated in a number of frequency bands.

3. A hearing device according to claim 1 wherein at least one of said detector signals is frequency dependent.

4. A hearing device according to claim 1 wherein the activation control unit is configured to control the anti-feedback system based on a predefined criterion comprising said detector signals.

5. A hearing device according to claim 2 configured to allow the activation control unit to bring the anti-feedback system in a first band into a first one of said modes of operation, and to bring the anti-feedback system in a second band into a second one of said modes of operation.

6. A hearing device according to claim 1 wherein the anti-feedback system is configured to be operated only in a limited number of frequency bands.

7. A hearing device according to claim 1 wherein the number of detectors comprises a level detector for estimating a current level of a signal of the forward path.

8. A hearing device according to claim 1 wherein the number of detectors comprises an auto-correlation detector for providing a measure of the current auto-correlation of a signal of the forward path.

9. A hearing device according to claim 8 wherein the activation control unit is configured to bring the anti-feedback system in an ON-mode, if said measure of the current auto-correlation fulfils a predefined auto-correlation-criterion for the ON-mode AND if the current level of a signal of the forward path fulfils a predefined level-criterion for the ON-mode.

10. A hearing device according to claim 8 wherein the activation control unit is configured to bring the anti-feedback system in an OFF-mode, if said measure of the current auto-correlation fulfils a predefined auto-correlation-criterion for the OFF-mode AND if the current level of a signal of the forward path fulfils a predefined level-criterion for the OFF-mode.

11. A hearing device according to claim 1 comprising first and second input transducers, and corresponding first and second configurable feedback cancellation systems comprising first and second feedback estimation units for estimating first and second acoustic feedback paths from said output transducer to said first and second input transducers, respectively.

12. A hearing device according to claim 1 wherein—in a mode of operation of the anti-feedback system other than the maximum power ON-mode—the update frequency of the update part is scaled down by a predefined factor X compared to a maximum update frequency.

13. A hearing device according to claim 1 wherein the activation control unit is configured—in a specific ON-mode of operation—to control the update parts of the first and second feedback estimation units to alternatingly update the filter coefficients of the respective variable filter parts.

14. A hearing device according to claim 1 wherein the hearing device comprises a hearing aid, a headset, an earphone, an ear protection device or a combination thereof.

15. A hearing device according to claim 1 wherein a switching time period for activation of an ON-mode is smaller than the switching time period for activation of an OFF-mode.

16. A hearing device according to claim 1 wherein the number of detectors are configured to provide that a switching time period for activation of an ON-mode is smaller 100 ms.

17. A binaural hearing aid system comprising first and second hearing device according to claim 1 , wherein the binaural hearing system is adapted to establish a communication link between the first and second hearing devices and to provide that information can be exchanged or forwarded from one to the other.

18. A binaural hearing aid system according to claim 17 configured to provide that a detector signal defining a measure of a first property of a signal of the forward path of a given hearing device is transmitted to the other hearing device for comparison with a measure of the first property of a signal of the forward path of the other hearing device, wherein the comparison is used to influence a whether or not a change of mode of operation of the anti-feedback system of the hearing aid in question should be initiated.

19. A binaural hearing aid system according to claim 18 wherein the property comprises auto-correlation.

20. A hearing device according to claim 1 configured so that
the configurable update frequency has a maximum value in the maximum power consumption ON-mode of the anti-feedback system, and
in different modes of operation of the anti-feedback system other than the maximum power consumption ON-mode, the update frequency of the update part is scaled down with different factors compared to said maximum value of the configurable update frequency.

Assignees

• Oticon As

Inventors

• Kristensen Michael Smed
• Meng Anders
• Munk Steen Michael

Classifications

• H04R25/453

  electronically · CPC title

• H04R25/00 Primary

  Electric hearing aids · CPC title

• H04R2460/03

  Aspects of the reduction of energy consumption in hearing devices · CPC title

• H04R25/552 Primary

  Binaural · CPC title

• H04R25/505 Primary

  using digital signal processing · CPC title