CIC Hearing Device Variable Gain Amplifier Quiescent Current Control

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Solution Overview

Problem

Conventional hearing devices face challenges in reducing power consumption while maintaining sound quality and durability, especially for deep in-the-canal extended wear models, due to limitations in battery configuration and electronics design that affect current consumption, noise levels, and distortion.

Innovation Solution

The development of a hearing device with a variable gain amplifier and input buffering circuitry using a Sziklai pair, along with a high impedance receiver winding positioned close to the tympanic membrane, and a rechargeable battery, to minimize quiescent current and enhance sound quality by using logarithmic compression and envelope filtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional battery configuration and electronics design are used in deep in-the-canal hearing devices, then the device can be miniaturized to fit the ear canal, but power consumption increases and battery life decreases

Engineering Contradiction:

Improvedevice sizeVSAvoidpower consumption

Core Design Contradiction:

Volume of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by modifying the electrical characteristics of the receiver winding (using high impedance windings) and implementing logarithmic compression in the amplifier circuit. These parameter changes allow the system to operate efficiently at lower power levels while maintaining audio quality, directly addressing the contradiction between miniaturization and power consumption in CIC hearing devices.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If the receiver is positioned close to the tympanic membrane to improve sound quality, then acoustic performance increases, but the device occupies more of the limited ear canal volume

Engineering Contradiction:

Improvesound qualityVSAvoiddevice volume

Core Design Contradiction:

Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The patent implements nesting by positioning the receiver deep in the ear canal near the tympanic membrane while housing the battery, amplifier, and other electronics in the limited space between the receiver and the ear canal aperture. This nested arrangement allows optimal acoustic positioning without exceeding ear canal volume constraints.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Use of energy by moving object

If low power electronics are used to reduce power consumption, then battery life extends, but noise levels and distortion increase

Engineering Contradiction:

Improvepower consumptionVSAvoidnoise and distortion

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent employs feedback mechanisms through logarithmic compression and envelope filtering in the amplifier circuit. These feedback-based signal processing techniques allow the low-power electronics to maintain low noise and distortion by dynamically adjusting gain based on input signal characteristics, resolving the contradiction between power consumption and audio quality.

Inventive Principle:

Principle #23Feedback

4Duration of action of moving object

If a rechargeable battery is used to extend battery life, then operational duration increases, but the device complexity and charging requirements increase

Engineering Contradiction:

Improvebattery lifeVSAvoiddevice complexity

Core Design Contradiction:

Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the hearing device with a rechargeable battery system that serves multiple functions: providing extended operational life, enabling user convenience through rechargeability, and integrating charging functionality within the compact CIC form factor. The device incorporates universal charging interfaces and power management circuitry that handle both power storage and recharging operations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design achieves reduced power consumption, improved sound quality, and extended battery life, meeting operational criteria such as low noise and distortion, while fitting within the constraints of the ear canal's volume, thereby addressing the limitations of existing technologies.

Implementation Method 1

a hearing device core including an acoustic-to-electric transducer or sensor that converts sound into an electrical signal

Methodology Applied

Scientific EffectAcoustic-to-electric transduction:

Implementation Method 2

a receiver, and electronics configured to receive the electrical signal as an input signal and generate an output signal provided to the receiver

Methodology Applied

Scientific EffectElectromagnetic transduction:

Data Source

PatentUS9456285B2CIC hearing device

Publication Date: 2016.09.27 SONOVA AG

AI summary

CIC Hearing device (50, 1000, 1100) comprising electronics configured to receive an electrical signal as an input signal and generate an output signal provided to a receiver, the electronics including a variable gain amplifier with input buffering circuitry including a compound transistor, the electronics being configured to bias the compound transistor such that a quiescent current associated with the output signal is limited or controlled.