Adaptive Noise Cancellation Power Management in Personal Audio
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Solution Overview
Problem
Personal audio devices, such as wireless telephones and headphones, face challenges in extending battery life due to the power consumption of adaptive noise cancellation (ANC) features, which are not effectively managed in existing technologies.
Innovation Solution
A personal audio system with an integrated circuit that includes a microphone for ambient noise measurement, an ANC processing circuit to generate an anti-noise signal, and a power manager that sets a power conservation mode when background noise levels are low, reducing unnecessary power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive noise cancellation (ANC) is continuously activated to improve audio quality, then noise cancellation performance is improved, but power consumption increases and battery life decreases
Solution Approach 1:
The system dynamically adjusts the ANC processing state based on real-time noise level detection. The power manager continuously monitors background noise through the microphone and transitions between full ANC processing, reduced processing, and disabled states, making the system adaptive rather than static in its power consumption characteristics
Solution Approach 2:
The system changes the operational parameters of the ANC processing circuit by adjusting the noise threshold levels and processing intensity based on detected environmental conditions. When noise levels fall below thresholds (first or second thresholds), the system modifies processing parameters to reduce power consumption while maintaining acceptable performance
2Reliability
If ANC processing is continuously active to maintain noise cancellation, then audio quality is improved, but battery life is reduced
Solution Approach 1:
The system implements periodic monitoring of noise levels through the microphone and periodically adjusts ANC processing state accordingly. Rather than continuous full-power processing, the system uses periodic assessment to determine when to activate, reduce, or disable processing, creating an intermittent operation pattern that extends battery life
Solution Approach 2:
The invention extracts and removes unnecessary ANC processing operations when they are not needed for effective noise cancellation. By detecting low noise environments and disabling or reducing processing in those conditions, the system eliminates wasteful power consumption while preserving audio quality when it matters
3Reliability
If the ANC system operates at full processing power to handle all noise levels, then noise cancellation effectiveness is improved, but power management efficiency deteriorates
Solution Approach 1:
The power manager segments the ANC processing operation into distinct power states: full processing mode for high noise levels, reduced processing mode for moderate noise levels, and disabled mode for low noise levels. This segmentation allows the system to match processing intensity to actual environmental needs, improving power management efficiency
Solution Approach 2:
The system applies partial processing action by using reduced processing intensity when noise levels are moderate rather than applying full processing power. This partial action approach consumes less power while still providing adequate noise cancellation for the actual environmental conditions
Data Source
AI summary
A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from an output of a microphone that measures ambient audio. The anti-noise signal is combined with source audio to provide an output for a speaker. The anti-noise signal causes cancellation of ambient audio sounds that appear at the microphone. A processing circuit estimates a level of background noise from the microphone output and sets a power conservation mode of the personal audio device in response to detecting that the background noise level is lower than a predetermined threshold.