MEMS Microphone Clock Reconfiguration for Seamless Mode Switching
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Solution Overview
Problem
Existing digital microphones require a restart to change operating modes, leading to restart delays and potential switching artefacts.
Innovation Solution
A method and circuit that allow seamless mode changes without restart, using a clock divider and multiplexer to adjust internal clock rates and maintain a constant output signal clock rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the microphone restarts during mode changes to adjust between low power and high performance operating modes, then the operating modes can be switched, but this causes delays and switching artefacts that disrupt the acoustic signal
Solution Approach 1:
The system performs preliminary actions by maintaining the MEMS device in a ready state during mode transitions. The clock divider and multiplexer are pre-configured to enable seamless switching between sampling rates without requiring a restart of the MEMS device, thus preventing signal disruption and switching artifacts.
Solution Approach 2:
A clock divider circuit is introduced as an intermediary component between the clock source and the ADC. This clock divider enables smooth transition between different sampling rates by dividing the clock signal appropriately, allowing mode changes without restarting the MEMS device and thereby maintaining signal continuity.
2Adaptability or versatility
If the microphone restarts during mode changes, then operating modes can be adjusted, but this increases design complexity
Solution Approach 1:
The clock divider circuit serves multiple functions: it enables mode switching, maintains signal continuity, and eliminates the need for separate power mode detection blocks. By making this single component multi-functional, the overall design complexity is reduced while maintaining adaptability between operating modes.
Solution Approach 2:
The invention extracts and eliminates the need for power mode detection blocks from the design. By using a clock divider and multiplexer configuration, the system can detect and respond to mode changes without requiring separate detection circuitry, thereby simplifying the overall design.
3Use of energy by moving object
If the internal clock rate is changed during operation, then power consumption and performance can be adjusted, but this requires seamless transitions without restarts
Solution Approach 1:
The system dynamically adjusts the internal clock rate during operation by using a clock divider and multiplexer. This dynamic adjustment allows the ADC to switch between different sampling rates (and thus power consumption levels) without restarting the MEMS device, ensuring smooth transitions and maintaining operational ease.
Data Source
AI summary
A method of operating a microelectromechanical system (MEMS) includes, in a first operational mode, converting an analog output of the MEMS into a first internal data stream and a first external data stream having a first sampling rate; transitioning from the first operational mode to a second operation mode without restarting the MEMS; and in the second operational mode, converting the analog output of the MEMS into a second internal data stream having a second sampling rate different from the first sampling rate, and performing a sampling rate conversion of the second internal data stream to generate a second external data stream.