Portable Media Speaker Power Control for Battery-Limited Playback
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Solution Overview
Problem
Portable media players face challenges in managing power consumption when connected to large speaker systems, as the power requirements for driving the speakers exceed the device's capabilities, leading to limited playback time and potential audio artifacts during power loss.
Innovation Solution
A method is implemented to manage power by setting a maximum allowable sound pressure level for speakers based on the available charge, reducing the sound pressure level when power is low, and providing user feedback to initiate a graceful shutdown to avoid audio artifacts, using a processor and power monitoring system to adjust the sound output and conserve energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the portable media player is connected to large speaker systems, then the audio output capability is improved, but the power consumption exceeds the device's capabilities
Solution Approach 1:
The patent implements dynamic power management that adjusts the maximum allowable sound pressure level (SPL) based on the operating mode (DC battery-powered vs AC mains-powered). The system dynamically changes the SPL ceiling parameter to match available power resources, allowing full power output when AC-powered and limited power output when battery-powered, thus resolving the contradiction between audio output capability and power consumption.
2Use of energy by moving object
If the maximum sound pressure level is limited in DC mode, then the power consumption is reduced, but the audio output capability is reduced
Solution Approach 1:
The patent changes the operating parameter (maximum allowable SPL) based on the power source condition. When transitioning from AC to DC mode, the system changes the SPL parameter from a higher ceiling to a lower ceiling, optimizing power consumption for battery operation. This parameter adaptation resolves the contradiction by matching output capability to available power resources.
3Duration of action of moving object
If the audio amplifier continues operating during power loss, then the audio playback continues, but audio artifacts are generated
Solution Approach 1:
The patent implements preliminary detection of power loss conditions and triggers a graceful shutdown sequence before complete power depletion occurs. The system monitors power status and preemptively begins the shutdown process, muting the audio amplifier and powering down components in a controlled manner, thus preventing audio artifacts while maximizing playback duration until power loss.
Data Source
AI summary
A consumer electronic product (e.g., a portable media player ported to a media delivery accessory) is powered by a limited capacity DC power source (such as a battery or mini-fuel cell). The consumer electronic product limits the maximum allowable sound pressure level (SPL) that can be produced by the speakers. In one embodiment, the maximum allowable SPL is based upon an amount of stored energy available in the limited capacity DC power source.