Audio Amplifier Selection by Audio Type for Fidelity and Efficiency

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Solution Overview

Problem

Existing audio amplifiers face a trade-off between audio fidelity and power consumption, with class A amplifiers providing low distortion but low efficiency, and class D amplifiers being power-efficient but introducing significant distortion, especially in PA/GA systems where speech audio requires linearity and alarm audio demands high efficiency to prevent overheating.

Innovation Solution

An audio amplifier system that selects between a linear class A/AB amplifier for voice audio and a power-efficient class D amplifier for alarm audio using an indicator signal, allowing for optimized amplification based on the audio type, ensuring accurate representation of voice volume and preventing overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a class A amplifier is used for voice audio, then low distortion is achieved, but power efficiency deteriorates

Engineering Contradiction:
Improveaudio fidelityVSAvoidpower efficiency
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The system dynamically switches between class A and class D amplifier modes based on the audio signal type detected by the indicator signal. For voice audio, class A mode provides low distortion with high linearity, while for alarm audio, class D mode provides high power efficiency. This dynamic adaptation resolves the contradiction by selecting the appropriate amplifier class for each audio type.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameters of the amplifier by switching between different amplifier classes (A and D) based on the audio signal characteristics. The selector control changes the amplification mode parameter according to the indicator signal, allowing optimal performance for each audio type without compromise.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If a class D amplifier is used for alarm audio, then power efficiency is improved, but distortion increases

Engineering Contradiction:
Improvepower efficiencyVSAvoidaudio fidelity
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The system dynamically selects class D amplifier mode when alarm audio is detected through the indicator signal. This allows the system to exploit the high power efficiency of class D amplification for alarm signals where linearity requirements are less stringent, while avoiding the use of class D for voice audio where fidelity is critical.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the amplification mode parameter to class D when processing alarm audio, optimizing power efficiency for this specific application. The selector control implements this parameter change based on the audio type identification, allowing the system to achieve high efficiency without compromising voice audio quality.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a single amplifier is used for both voice and alarm audio, then device complexity is reduced, but performance deteriorates

Engineering Contradiction:
Improveamplifier configurationVSAvoidaudio fidelity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The invention creates a universal amplifier system that can handle both voice and alarm audio by incorporating two amplifier stages (class A and class D) with a selector control. The multi-functionality is achieved through the selector control that routes different audio types to appropriate amplifier stages, allowing a single device to optimize performance for multiple audio applications.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The amplifier system is segmented into two distinct amplification paths (class A and class D) that are selectively activated based on audio type. This segmentation allows each amplifier stage to be optimized for its specific audio type, with the selector control managing the division of labor between the two stages.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2755322B1An audio amplifier
Publication Date: 2018.08.15 EATON INTELLIGENT POWER LTD
  • EP2755322B1 patent drawingFigure 1
  • EP2755322B1 patent drawingFigure 2

AI summary

There is provided an audio amplifier (200) for amplifying an audio signal (113, 118, 205), the audio amplifier comprising a first amplifier (A1), a second amplifier (A2), and a selector control (210), wherein the selector control is configured to select which one of the first amplifier and the second amplifier is used to amplify the audio signal, based upon an indicator signal (150) that specifies a type of audio carried by the audio signal.