MEMS Sensor Synchronization via External Reference Signal

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Solution Overview

Problem

Existing methods for synchronizing output signals from multiple MEMS sensors in electronic apparatuses are costly, energy-intensive, and lack versatility, particularly when high output-data rates are required, as they often involve additional devices or complex calculation and communication protocols.

Innovation Solution

A synchronization method where one sensor acts as a master, generating an external reference signal that synchronizes the output signals of other sensors, allowing them to operate at the same frequency and phase, reducing the need for additional hardware and complex control unit resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional devices are incorporated for synchronization, then synchronization accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improvesynchronization accuracyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensor system performs self-synchronization by having each sensor independently generate its output signal based on its own operating frequency, eliminating the need for external synchronization devices. The control unit simply collects signals from all sensors without active intervention in the synchronization process, allowing the system to self-organize temporal coherence among sensors.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces a temporal coherence verification mechanism that acts as an intermediary to assess whether sensor signals are synchronized. This verification layer allows the system to determine if synchronization is achieved without requiring complex active synchronization hardware, as the intermediary only needs to check temporal relationships rather than enforce them.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If complex calculation resources are used for synchronization, then synchronization precision is improved, but energy consumption increases

Engineering Contradiction:
Improvesynchronization precisionVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control unit performs only partial synchronization verification by checking temporal coherence of signals rather than actively controlling each sensor's timing. This partial action approach achieves sufficient synchronization precision for most applications without the excessive energy consumption of full active synchronization control.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

Sensors independently maintain their own timing and frequency characteristics without requiring continuous control unit intervention. The control unit only verifies temporal coherence when needed, allowing sensors to self-manage their operation and significantly reducing the energy burden on the control unit.

Inventive Principle:
Principle #25Self-service

3Reliability

If dedicated communication interface is implemented, then synchronization control is improved, but versatility and simplicity are reduced

Engineering Contradiction:
Improvesynchronization controlVSAvoidversatility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The control unit uses a universal data collection interface that can receive signals from multiple different sensor types without requiring dedicated synchronization communication channels. This multi-functional approach allows the same interface to handle both data acquisition and synchronization verification, maintaining system versatility while achieving synchronization control.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Productivity

If high output-data rate is required, then data collection speed is improved, but synchronization complexity increases

Engineering Contradiction:
Improveoutput-data rateVSAvoidsynchronization complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Sensors are configured with predetermined operating frequencies and temporal characteristics before data collection begins. This preliminary configuration allows sensors to generate signals at required high data rates with inherent temporal coherence, eliminating the need for complex real-time synchronization processing during high-speed data collection.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4067830B1Sensor, in particular MEMS sensor, for the generation of an output digital signal, coupleable to a plurality of sensors in an electronic apparatus
Publication Date: 2024.10.09 STMICROELECTRONICS SRL
  • EP4067830B1 patent drawingFigure 1
  • EP4067830B1 patent drawingFigure 2
  • EP4067830B1 patent drawingFigure 3

AI summary

The integrated sensor (5A-5C) is configured to receive a frequency-indication signal (EXT_REF) and to supply an output digital signal (SO) formed by a plurality of samples. The integrated sensor has a digital detector (48), which detects a physical quantity and generates a discrete detection signal (SD) indicative of the detected physical quantity; an output timing regulation block (80, 83), which receives the frequency-indication signal and a set of local reference signals (CLK, INT_REF) and generates a trigger signal (OUT_TRG) as a function of the frequency-indication signal and of the set of local reference signals; and an output stage (49), which receives the discrete detection signal and the trigger signal (OUT_TRG) and supplies the digital output signal (SO) and a locking signal (EXT_REF, INT_REF). The output stage (49) supplies a sample of the discrete detection signal in response to the reception of the trigger signal, thus generating the digital output signal, and supplies the locking signal in response to the reception of the trigger signal. The locking signal is temporally aligned with the digital output signal.