Audio Amplifier Control Using Frequency-Selective Attenuation
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Solution Overview
Problem
Audio systems face challenges in managing power consumption and protecting amplifiers from damage due to high drive signals and varying impedance frequencies, which can lead to reduced battery life and potential thermal issues in mobile devices.
Innovation Solution
An audio system controller that utilizes an amplifier-operating-condition-signal and a maximum-threshold-value to generate control signalling, which sets operating parameters for an audio processor based on a frequency-dependent impedance function of the load, attenuating audio signals in low-impedance-frequency-bands more than in high-impedance-frequency-bands, thereby reducing power consumption and protecting the amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the audio signal level is raised to improve sound quality, then the audio output quality is improved, but the power consumption of the amplifier increases and may cause thermal damage
Solution Approach 1:
The patent applies local quality by differentiating power management across different frequency bands. The controller identifies low-impedance frequency bands where the load draws excessive current and applies targeted attenuation specifically to those bands, while leaving other frequency bands unaffected. This selective local intervention reduces overall power consumption while preserving audio quality in non-problematic frequency ranges.
Solution Approach 2:
The system dynamically changes the attenuation parameter based on the amplifier's operating conditions and the frequency-dependent impedance characteristics of the load. By monitoring amplifier temperature and current consumption, the controller adjusts the degree of attenuation applied to different frequency bands, optimizing the balance between audio output quality and power consumption in real-time.
2Power
If high drive signals are supplied to increase audio output, then the audio signal strength is improved, but the amplifier may suffer from thermal damage and over-current conditions
Solution Approach 1:
The system implements preliminary anti-action by proactively identifying and attenuating audio signals in low-impedance frequency bands before they can cause harmful current levels in the amplifier. The controller continuously monitors the impedance characteristics and preemptively reduces signal strength in problematic bands, preventing thermal damage and over-current conditions before they occur.
Solution Approach 2:
The patent employs feedback mechanisms where the controller monitors amplifier operating conditions (temperature, current consumption) and the frequency-dependent impedance of the load. Based on this feedback, the controller dynamically adjusts the attenuation applied to different frequency bands, creating a closed-loop system that maintains amplifier safety while preserving audio output quality.
3Use of energy by moving object
If frequency-dependent impedance compensation is applied to reduce power consumption, then the power efficiency is improved, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The system applies preliminary action by pre-characterizing the frequency-dependent impedance profile of the load during manufacturing or initial setup. This impedance profile is stored in memory and used by the controller to identify low-impedance frequency bands. By performing this characterization work in advance, the runtime control complexity is reduced to simply looking up pre-computed attenuation values for each frequency band.
Solution Approach 2:
The controller performs self-service by autonomously monitoring amplifier operating conditions and automatically adjusting attenuation levels without requiring external intervention. The system uses its own internal sensors and processors to detect problematic frequency bands and apply appropriate compensation, eliminating the need for additional external control hardware or manual adjustment mechanisms.
Data Source
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AI summary
A controller for an audio system. The audio system comprising an audio processor and an amplifier. The controller is configured to: receive an amplifier-operating-condition-signal representative of an operating condition of the amplifier; receive a maximum-threshold-value; and generate control signalling based on the amplifier-operating-condition-signal and the maximum-threshold-value, wherein the control signalling is configured to set an operating parameter of the audio processor.