Power efficient hearing aid

• US 5,321,758 A
• Filed: 10/08/1993
• Issued: 06/14/1994
• Est. Priority Date: 03/02/1989
• Status: Expired due to Fees

• Current Assignee: Ensoniq Corp. (Creative Technology Ltd.)
• Original Assignee: Ensoniq Corp. (Creative Technology Ltd.)
• Inventors: Charpentier, Albert J., Loeper, Duane J., McLaughlin, Brian J., DiOrio, David W., Gauthier, Edouard A.
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US08/134,495
• Time in Patent Office: 249 Days
• Field of Search: 381/67, 381/68, 381/68.1, 381/68.2, 381/68.4, 381/94, 381/83, 381/93, 381/120, 330/202, 330/297
• US Class Current: 381/317
• CPC Class Codes: H04R 2225/41 Detection or adaptation of hearing aid parameters or programs to listening situation, e.g. pub, forest
• CPC Class Codes: H04R 2430/03 Synergistic effects of band splitting and sub-band processing
• CPC Class Codes: H04R 2460/03 Aspects of the reduction of energy consumption in hearing devices
• CPC Class Codes: H04R 25/356 Amplitude, e.g. amplitude shift or compression
• CPC Class Codes: H04R 25/505 using digital signal processing

Abstract

A power efficient hearing aid uses a programmable biasing technique to set the quiescent operating points of amplifiers used by the hearing aid to avoid excessive power usage by the hearing aid. The hearing aid also includes power supply circuitry which develops +1.25 volts and -1.25 volts relative to ground from a single +1.25 volt source. The hearing aid also conserves power by selectively disabling low frequency signal processing channels in the presence of relatively large amplitude ambient noise.

Claims

1. In a hearing aid, including a microphone for receiving acoustic energy and for converting said acoustic energy into electrical signals occupying a predetermined band of frequencies, and signal processing means including a plurality of signal processing channels operating in parallel and having respective frequency response characteristics for processing electrical signals in a respective plurality of sub-bands of said predetermined band of frequencies, a method of operating said hearing aid to reduce objectionable externally generated background noise, said method comprising the steps of:

monitoring said electrical signals to change the state of a control signal from a first state to a second state when said electrical signals indicate that the average acoustic energy, including the externally generated background noise, received by said microphone has become greater than a first threshold value;

disabling a first one of said plurality of signal processing channels responsive to said control signal being in said second state to cause the hearing aid to use less power than if the one signal processing channel were enabled while the background noise is present;

changing the state of said control signal from said second state to said first state when the electrical signals indicate that the average acoustic energy received by said microphone has become less than a second threshold value, said second threshold value being less than said first threshold value; and

reenabling said one signal processing channel responsive to said control signal undergoing a transition from said second state to said first state.

2. A hearing aid, comprising:

a microphone for receiving acoustic energy including externally generated background noise and for converting said acoustic energy into electrical signals occupying a predetermined band of frequencies;

signal processing means including a plurality of signal processing channels operating in parallel for processing a respective plurality of electrical signals representing acoustic energy in a respective plurality of sub-bands of said predetermined band of frequencies;

monitoring means, responsive to first and second ones of said plurality of electrical signals for generating a control signal which changes from a first state to a second state when the first and second electrical signals indicate that the average acoustic energy received by said microphone has become greater than a first threshold value and which changes from the second state to said first state when the first and second electrical signals indicate that the average acoustic energy received by said microphone has become less than a second threshold value, said second threshold value being less than said first threshold value; and

switching means, responsive to said control signal undergoing a transition from said first state to said second state for disabling a first one of said signal processing channels to reduce, in magnitude, signals representing the externally generated background noise and to cause the hearing aid to use less power than if said one signal processing channel were enabled while the background noise is present, and responsive to said control signal undergoing a transition from said second state to said first state for reenabling said first signal processing channel.

3. The hearing aid set forth in claim 2, wherein:

said monitoring means includes means for generating a further control signal which changes from a first state to a second state when the first and second electrical signals indicate that the average acoustic energy received by said microphone is greater than a third threshold value, said third threshold value being greater than said first threshold value; and

said switching means includes means for disabling a second one of said plurality of signal processing channels responsive to a transition of said further control signal from said first state to said second state.