Always-On Microphone Audio Activity Detection for Low-Power Wake-Up
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Solution Overview
Problem
Current digital microphone technologies rely on pure current optimization techniques for low power operation, which are not dependent on audio activity detection, leading to inefficient power usage and inability to accurately differentiate between ambient and non-ambient audio activity.
Innovation Solution
An audio activity detector device with a closed loop feedback regulating circuit, including an automatic gain control (AGC) circuit, quantizer circuit, and signal processing to determine key statistic values and gain control values, allowing the microphone to transition between power states based on detected audio activity, reducing power consumption during ambient noise and rapidly switching to higher power when non-ambient noise is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If pure current optimization techniques are used for low power operation, then power consumption is reduced, but the ability to differentiate between ambient and non-ambient audio activity is lost
Solution Approach 1:
The patent implements dynamic power management by transitioning the microphone between different power states (low power mode and high power mode) based on detected audio activity. The system dynamically adjusts its operational characteristics rather than maintaining a fixed state, allowing it to optimize power consumption while maintaining detection accuracy when needed.
Solution Approach 2:
The system uses feedback from audio activity detection to control power state transitions. The detected audio activity serves as feedback that triggers transitions between power states, creating a closed-loop control system that adapts power consumption to actual operational needs.
2Speed
If the microphone remains in always-on state, then audio detection responsiveness is improved, but power consumption increases
Solution Approach 1:
The system employs periodic monitoring of audio activity to determine when to transition from low power mode to high power mode. Instead of continuous high-power operation, the system periodically checks for audio activity and adjusts its state accordingly, achieving a balance between responsiveness and power consumption.
Solution Approach 2:
The system performs preliminary audio activity detection in a low-power state before transitioning to full operational mode. This preliminary action allows the system to prepare for potential audio events without committing to continuous high-power operation, enabling fast wake-up when needed while minimizing overall power consumption.
3Use of energy by moving object
If audio activity detection is implemented, then power management is optimized, but device complexity increases
Solution Approach 1:
The patent segments the power management system into distinct functional blocks: audio activity detection circuitry, power state control logic, and power state machine. This segmentation allows each component to be optimized independently and simplifies the overall design by creating modular, manageable units with clear interfaces.
Solution Approach 2:
The system introduces an intermediary power state control mechanism that mediates between the audio activity detection and the actual power state transitions. This intermediary layer simplifies the control logic by providing a standardized interface and abstraction layer, reducing the overall system complexity despite adding power management functionality.
Data Source
AI summary
An audio activity detector device is disclosed. The audio activity detector device comprises a closed loop feedback regulating circuit that supplies an input signal representative of a time-varying voltage signal to a quantizer circuit, wherein the quantizer circuit, as a function of the input signal, converts the input signal to a quantizer discrete-time signal; a first circuit that, as a function of the discrete-time signal, determines a key quantizer statistic value for the quantizer discrete-time signal; and a second circuit that, as a function of the key quantizer statistic value, determines a signal statistic value for the input signal and a gain control value.