Magnetic Detection Device AC Noise Cancellation Timer Reset

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Solution Overview

Problem

Conventional magnetic detection devices face challenges in effectively canceling noise caused by alternating current (AC) magnetic fields without using external components like capacitors or resistors, and are not suitable for semiconductor integrated circuits due to complexity and component limitations.

Innovation Solution

A magnetic detection device with an amplifier circuit, timer circuits, and a logic circuit that generates a clock signal, allowing the device to eliminate AC magnetic field noise by resetting timers based on output changes, thereby preventing false detection and reducing power consumption, without requiring external components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional noise cancellation methods using capacitors and resistors are used, then AC magnetic field noise can be reduced, but the device cannot be formed as a semiconductor integrated circuit and occupies large area

Engineering Contradiction:

ImproveAC magnetic field noiseVSAvoidcircuit complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces the conventional electronic noise cancellation method (using capacitors and resistors) with a digital signal processing approach. The amplifier circuit outputs a detection signal that is then processed by a digital signal processor to remove AC magnetic field noise through software algorithms, eliminating the need for external passive components and enabling semiconductor integrated circuit formation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a digital signal processor as an intermediary between the amplifier circuit and the final output. This intermediary component receives the detection signal, processes it to remove noise, and outputs a cleaned signal, thereby solving the noise problem without requiring direct connection to external noise-cancellation components.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If external components like capacitors or resistors are used for noise cancellation, then AC magnetic field noise can be eliminated, but the device is not suitable for semiconductor integrated circuits

Engineering Contradiction:

ImproveAC magnetic field noiseVSAvoidsemiconductor integration

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements self-service by having the device cancel its own noise internally through integrated digital signal processing. The detection signal from the amplifier circuit is fed back to the digital signal processor which automatically removes noise without requiring external intervention or components, making the device self-sufficient and suitable for semiconductor integration.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If noise cancellation circuits are added to remove AC magnetic field noise, then detection accuracy improves, but power consumption increases

Engineering Contradiction:

Improvedetection accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by using a timer circuit that operates intermittently rather than continuously. The timer circuit is activated only when the detection signal exceeds a threshold level, indicating the presence of a magnetic field, thereby performing noise cancellation only when necessary and reducing overall power consumption compared to continuous operation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent implements preliminary action through the timer circuit that starts counting only when the detection signal indicates the presence of a magnetic field. This preliminary check prevents the noise cancellation processing from occurring unnecessarily, thereby saving power while maintaining detection accuracy when needed.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11860245B2Magnetic detection device and semiconductor integrated circuit for amplifying magnetic detection signal

Publication Date: 2024.01.02 MITSUMI ELECTRIC CO LTD

AI summary

A magnetic detection device that comprises an amplification circuit amplifying a detection signal from a magnetic sensor that is positioned, for example, in a location where an alternating current magnetic field enters as noise, and detects an alternating current magnetic field targeted for monitoring, said magnetic detection device further comprising: timer circuits that are activated in response to a change in the output of the amplification circuit, and if these clock a prescribed time, the outputs thereof change; a logic circuit that treats the outputs of the timer circuits as inputs; and an oscillation circuit for generating an operation clock signal for the timer circuits. The timer circuits are structured such that if the output of the amplification circuit changes to a different direction before the clocking of the prescribed time is complete, the timer circuits are reset.