Hearing Prosthesis Amplifier Switching for Frequency-Dependent Loads
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Solution Overview
Problem
Current hearing prostheses face challenges in efficiently amplifying electrical signals for different types of hearing loss, particularly in balancing power output and frequency-dependent impedance, which affects the perception of sound for users.
Innovation Solution
The proposed solution involves an output amplifier stage with multiple amplifiers, including a step-up converter and a class-D amplifier, which can operate in different modes and frequency bands, coupled with a controller that adjusts power supply characteristics and impedance to optimize signal amplification for various hearing prosthesis applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single amplifier is used in hearing prostheses, then the device structure is simple, but it cannot efficiently amplify signals across different frequency bands with varying impedance
Solution Approach 1:
The amplifier is divided into multiple independent amplifier stages, each optimized for specific frequency bands and impedance ranges. This segmentation allows each stage to handle particular signal characteristics efficiently while maintaining overall system adaptability without excessive complexity.
Solution Approach 2:
The amplifier system dynamically switches between different amplifier stages based on the input signal's frequency content and impedance characteristics. This dynamic adaptation enables the system to optimize performance for different hearing loss types and frequency ranges without requiring a completely different device design.
2Reliability
If high power output is provided for all frequency bands, then sound perception is improved, but power consumption increases significantly
Solution Approach 1:
Different amplifier stages provide different power output levels tailored to specific frequency bands and impedance requirements. This local optimization ensures that power is concentrated where needed for effective sound perception while avoiding unnecessary power consumption in frequency ranges that require less energy.
Solution Approach 2:
The system changes operating parameters such as voltage, current, and impedance matching across different amplifier stages to optimize power efficiency. By adjusting these parameters according to the specific frequency band and load requirements, the system achieves reliable sound perception with minimized overall power consumption.
3Adaptability or versatility
If multiple amplifiers operate continuously across all frequencies, then comprehensive signal coverage is achieved, but quiescent power consumption increases
Solution Approach 1:
The multiple amplifier stages operate periodically or on-demand rather than continuously. The system activates specific amplifier stages only when signals in their designated frequency bands are detected, providing comprehensive frequency coverage while minimizing quiescent power consumption during idle periods.
Solution Approach 2:
The amplifier system is designed with multi-functional capability where a single integrated circuit can perform multiple amplifier functions across different frequency bands. This universal design allows comprehensive signal coverage while reducing the need for separate continuously-operating amplifier circuits for each frequency range.
4Power
If high voltage and high current are provided to the load, then output power is sufficient, but the amplifier circuit becomes larger and less compact
Solution Approach 1:
The high power output requirement is segmented across multiple amplifier stages, each operating at lower voltage and current levels. This segmentation allows the use of smaller, more compact components in each stage while achieving the required total output power through the combined operation of all stages.
Solution Approach 2:
The amplifier system dynamically switches between different voltage and current operating modes depending on the signal requirements. By using lower voltage/higher current modes for low-impedance loads and higher voltage/lower current modes for high-impedance loads, the system achieves sufficient output power with compact circuit design without requiring continuously high voltage and current capability.
Data Source
AI summary
A hearing prosthesis circuit includes a power source, a first amplifier coupled to the power source, and a second amplifier coupled to the power source. The circuit also includes a stimulation component coupled to the first amplifier and the second amplifier. The stimulation component is configured to provide an output in accordance with an electrical signal that includes audio data. Further, the circuit includes a controller coupled to the first amplifier and the second amplifier. The controller is operable in accordance with a first operational setting to use the first amplifier to provide the electrical signal to the stimulation component and the controller is also operable in accordance with a second operational setting to use the second amplifier to provide the electrical signal to the stimulation component. Generally, the first amplifier provides greater signal amplification of the audio data than the second amplifier.