Gyro Sensor Circuit Noise Reduction via Digital Signal Interference Cancellation

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Solution Overview

Problem

Existing physical quantity measurement devices, such as gyro sensors, face challenges in maintaining measurement accuracy due to electrostatic coupling leakage from digital signals, which can introduce noise and reduce the accuracy of detected physical quantities like angular velocity.

Innovation Solution

A circuit device with a detection signal terminal, digital signal terminal, signal generation circuit, and amplification circuit that generates a noise reduction signal to counteract digital interference, using amplification and synchronization detection to reduce noise components and enhance measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If digital signal terminals are added for communication functionality, then device functionality and productivity are improved, but electrostatic coupling leakage increases causing measurement precision to deteriorate

Engineering Contradiction:

Improvecommunication functionalityVSAvoidphysical quantity measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

A capacitor is introduced as an intermediary element connected between the digital signal terminal and ground. This capacitor acts as a mediator that provides a preferential path for high-frequency noise signals to ground, preventing them from coupling into the detection circuit through parasitic capacitance while allowing the digital signal terminal to maintain its communication functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The parasitic capacitance between the digital signal terminal and detection circuit, which originally causes harmful electrostatic coupling leakage, is utilized beneficially. By connecting a capacitor to ground at the digital signal terminal, the system converts the harmful coupling effect into a useful noise filtering mechanism where the capacitor discharge path suppresses noise propagation through the parasitic capacitance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Measurement precision

If shielding films are disposed between wirings to reduce electrostatic coupling leakage, then measurement precision is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvephysical quantity measurement accuracyVSAvoidhardware structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The noise reduction function is extracted from the physical layout design (shielding films) and implemented through an electrical circuit element (capacitor). Instead of modifying the mechanical structure with shielding films, the solution extracts the essential function of noise suppression and achieves it through a simple capacitive element connected to ground.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical shielding film structure is replaced with an electrical circuit solution. Instead of using physical barriers (mechanical approach) to prevent electrostatic coupling, the invention uses an electrical capacitor to actively manage and redirect noise signals, substituting a complex mechanical shielding structure with a simple electrical component.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If offset components are adjusted by signal processing, then measurement precision is improved, but the solution does not address electrostatic coupling leakage from digital signals

Engineering Contradiction:

Improveangular velocity signal accuracyVSAvoidcompleteness of noise reduction

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The noise reduction approach is segmented into two distinct parts: (1) hardware-level prevention of digital signal coupling using the capacitor, and (2) signal processing-level correction of offset components. This segmentation allows each method to address its specific target without interference, providing comprehensive noise reduction that covers both digital signal leakage and offset errors.

Inventive Principle:

Principle #1Segmentation

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 proposed solution effectively reduces digital interference, improving the accuracy of physical quantity measurements by canceling noise components through differential signal processing and noise reduction techniques, thereby enhancing the reliability of devices like gyro sensors.

Implementation Method 1

a capacitor connected between a digital signal terminal and ground, wherein a noise reduction signal for reducing noise of the detection signal is generated by discharging the capacitor

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11209272B2Circuit device, physical quantity measurement device, electronic apparatus, and vehicle

Publication Date: 2021.12.28 SEIKO EPSON CORP

AI summary

A circuit device includes a detection signal terminal to which a detection signal from a vibrator is input, a digital signal terminal that performs at least one of an input and an output of a digital signal, a detection circuit, and a signal generation circuit that generates a noise reduction signal based on the digital signal. The detection circuit includes an amplification circuit that amplifies the detection signal. The amplification circuit performs addition processing of a signal obtained by amplifying the detection signal and the noise reduction signal.