Differential Amplifier Switching for Detection Arm Signal Separation

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Solution Overview

Problem

Existing physical quantity detection devices struggle to individually measure the vibration characteristics of detection arms due to the inability to distinguish between unnecessary signals, hindering appropriate balance tuning and performance improvement.

Innovation Solution

A physical quantity detection device with a circuit device that includes a differential amplifier circuit and switches to connect detection electrodes to specific input nodes, allowing for the differential amplification of detection signals from multiple detection arms, thereby enabling separate measurement and improved sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If detection signals from multiple detection arms are electrically connected to share common input nodes, then device complexity is reduced, but individual measurement precision of each detection arm deteriorates

Engineering Contradiction:
Improvecircuit connection complexityVSAvoidindividual measurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent divides the detection circuit into independent segments by providing separate input nodes (first input node and second input node) for different detection arms. Each detection arm can be individually connected to specific input nodes through switches, enabling independent measurement while maintaining circuit modularity. This segmentation resolves the contradiction by allowing both simplified overall structure and precise individual measurement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs switches to dynamically connect detection electrodes to different input nodes based on measurement requirements. This dynamic reconfigurability allows the circuit to adapt between different measurement modes (individual arm measurement vs. combined measurement), resolving the fixed contradiction between circuit simplicity and measurement precision by providing flexible connectivity options.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If detection electrodes are connected without grounding, then detection sensitivity is improved, but the ability to distinguish and individually measure signals from different detection arms deteriorates

Engineering Contradiction:
Improvedetection sensitivityVSAvoidsignal source identification
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent introduces switches as intermediary components between detection electrodes and input nodes. These switches act as mediators that control signal flow paths, enabling the system to maintain high sensitivity through differential amplification while simultaneously preserving signal source identification by selectively connecting specific detection electrodes to specific input nodes based on measurement mode.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If multiple detection signals are combined at common input nodes, then signal-to-noise ratio is improved through differential amplification, but the ability to perform balance tuning on individual detection arms deteriorates

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidbalance tuning capability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses dynamically controllable switches to reconfigure the circuit between measurement mode (combined signals for high SNR) and tuning mode (individual arm connections for balance adjustment). This dynamic reconfiguration resolves the contradiction by allowing the system to achieve both high signal-to-noise ratio through differential amplification and ease of balance tuning through selective individual arm connectivity.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enhances detection sensitivity by doubling the effective area of detection electrodes, improving signal-to-noise ratio and reducing noise, thus enhancing the device's performance in measuring physical quantities.

Implementation Method 1

The amplifier circuit includes a differential amplifier circuit, a first switch provided between the first terminal and a first input node of the differential amplifier circuit

Methodology Applied
Scientific EffectDifferential amplification:

Data Source

PatentEP4671682A1Physical quantity detection device
Publication Date: 2025.12.31 SEIKO EPSON CORP
  • EP4671682A1 patent drawingFigure 1
  • EP4671682A1 patent drawingFigure 2
  • EP4671682A1 patent drawingFigure 3

AI summary

A physical quantity detection device 1 includes a physical quantity detection element 10 and a circuit device 20. The physical quantity detection element 10 includes a detection arm AS1 including detection electrodes EL1A and EL1B and a detection arm AS2 including detection electrodes EL2A and EL2B. The circuit device 20 includes terminals T1, T2, T3, and T4 connected to the detection electrodes EL1A, EL1B, EL2A, and EL2B, and an amplifier circuit 120. The amplifier circuit 120 includes a differential amplifier circuit 128, a switch SW1A provided between the terminal T1 and an input node NI1 of the differential amplifier circuit 128, a switch SW1B provided between the terminal T2 and an input node NI2 of the differential amplifier circuit 128, a switch SW2A provided between the terminal T3 and the input node NI2, and a switch SW2B provided between the terminal T4 and the input node NI1.