Class-D Amplifier Voltage Control to Reduce Power Dissipation

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Solution Overview

Problem

Audio amplifiers, such as Class-D amplifiers, face inefficiencies due to power dissipation, which can be reduced by lowering the supply voltage, but this compromises amplifier performance and leads to user experience degradation if not managed properly.

Innovation Solution

A playback device that generates a voltage control signal based on metadata associated with its settings and the content to be played, using a media processor and voltage regulator to adjust the voltage level provided to the amplifier, avoiding the 'pumping' effect and maintaining performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the supply voltage to the amplifier is reduced to decrease power dissipation, then power consumption is reduced, but amplifier performance deteriorates

Engineering Contradiction:
Improvepower dissipationVSAvoidamplifier performance
Core Design Contradiction:
Loss of energyVSPower

Solution Approach 1:

The patent implements dynamic voltage control by adjusting the amplifier's supply voltage in real-time based on the actual audio signal characteristics (volume level, signal presence). The system transitions from static voltage supply to dynamic voltage supply that adapts to changing operational conditions, reducing voltage during low-activity periods and maintaining higher voltage during high-activity periods to preserve performance while minimizing power dissipation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the voltage parameter of the amplifier supply based on metadata analysis of the audio content and current playback settings. By analyzing signal characteristics and adjusting the voltage parameter dynamically rather than maintaining a fixed high voltage, the system achieves lower power dissipation without permanently compromising amplifier performance capability.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If voltage is reduced indiscriminately without considering playback settings and content, then power dissipation decreases, but user experience degrades significantly

Engineering Contradiction:
Improvepower dissipationVSAvoiduser experience
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The system incorporates feedback mechanisms by continuously monitoring playback settings (volume control metadata) and content characteristics (audio signal metadata), then using this information to make intelligent voltage adjustment decisions. This feedback loop ensures that voltage reduction decisions are based on actual operational needs rather than arbitrary reductions, preserving user experience while achieving power savings.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary analysis of the audio metadata and playback settings before adjusting voltage levels. By pre-analyzing the content characteristics and predicted signal activity, the system can proactively adjust voltage to appropriate levels before power dissipation becomes an issue, rather than reactively reducing voltage and degrading performance.

Inventive Principle:
Principle #10Preliminary action

3Loss of energy

If voltage changes are made unpredictably, then power dissipation may be reduced, but audible artifacts known as the 'pumping' effect occur

Engineering Contradiction:
Improvepower dissipationVSAvoidaudible artifacts
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The system implements periodic voltage adjustments based on the temporal characteristics of the audio signal metadata rather than continuous or unpredictable changes. By synchronizing voltage changes with the natural periodicity of the audio content (beat patterns, signal envelopes), the system avoids creating artificial periodic artifacts that would be perceived as pumping effects.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system maintains continuous monitoring of audio metadata and playback settings to ensure smooth, continuous voltage transitions rather than abrupt changes. This continuity approach prevents sudden voltage shifts that would create audible artifacts, while still achieving progressive power dissipation reduction through gradual voltage adjustments.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3818629B1Intelligent power reduction in audio amplifiers
Publication Date: 2024.10.16 ROKU INC
  • EP3818629B1 patent drawingFigure 1
  • EP3818629B1 patent drawingFigure 2
  • EP3818629B1 patent drawingFigure 3

AI summary

Disclosed herein is a device and method for intelligently reducing power consumption in an audio amplifier in the device, and in particular Class-D amplifiers, through the use of metadata associated with settings of the playback device and/or content to be played on the playback device. The device includes components for analyzing the settings and content metadata and regulates the voltage provided to the audio amplifier based on this analysis.