Magnetic Field Sensor Shared Path Amplifier ADC

Solution Overview

Problem

Magnetic field sensors often face manufacturing defects and faults during operation, which can be difficult to detect using existing self-test methods, leading to incomplete test coverage and potential performance degradation or interruption.

Innovation Solution

A magnetic field sensor design that includes a signal path with both a measured and a reference magnetic field signal processing capability, utilizing a dual-path analog-to-digital converter and a diagnostic trim circuit to generate a diagnostic signal indicative of faults, allowing for non-overlapping time periods for measurement and diagnostic processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If self-test circuitry is integrated into the magnetic field sensor, then fault detection capability is improved, but test coverage remains incomplete and may interrupt sensor operation

Engineering Contradiction:

Improvefault detection capabilityVSAvoidtest coverage completeness

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The signal processing path is segmented into two separate paths: a first path for processing measured magnetic field signals during normal operation, and a second path for processing reference magnetic field signals during self-test. This segmentation allows both measurement and diagnostic functions to operate simultaneously without interfering with each other, achieving complete test coverage while maintaining continuous sensor operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The magnetic field sensing element alternates between generating measured magnetic field signals during a measured time period and generating reference magnetic field signals during a reference time period. This periodic switching enables the sensor to perform self-tests at regular intervals without interrupting normal measurement operations, ensuring both reliability and continuous functionality.

Inventive Principle:

Principle #19Periodic action

2Reliability

If self-test is performed during operation, then continuous monitoring is improved, but sensor performance degrades or operation is interrupted

Engineering Contradiction:

Improvecontinuous monitoring capabilityVSAvoidsensor operation continuity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The magnetic field sensing element alternates between generating measured magnetic field signals during a measured time period and generating reference magnetic field signals during a reference time period. This periodic switching enables the sensor to perform self-tests at regular intervals without interrupting normal measurement operations, ensuring both reliability and continuous functionality.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The signal processing path is segmented into two separate paths: a first path for processing measured magnetic field signals during normal operation, and a second path for processing reference magnetic field signals during self-test. This segmentation allows both measurement and diagnostic functions to operate simultaneously without interfering with each other, achieving complete test coverage while maintaining continuous sensor operation.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If a single signal path is used for both measurement and diagnostic processing, then device complexity is reduced, but measurement and diagnostic processing interfere with each other

Engineering Contradiction:

Improvesignal path structureVSAvoidfault detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The signal processing path is segmented into two separate paths: a first path for processing measured magnetic field signals during normal operation, and a second path for processing reference magnetic field signals during self-test. This segmentation allows both measurement and diagnostic functions to operate simultaneously without interfering with each other, achieving complete test coverage while maintaining continuous sensor operation.

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

Enhances test coverage and fault detection accuracy, reducing the risk of performance degradation by enabling simultaneous measurement and diagnostic processing without interfering with sensor operation.

Implementation Method 1

at least one magnetic field sensing element configured to generate a measured magnetic field signal responsive to an external magnetic field

Methodology Applied

Scientific EffectMagnetic field sensing: Hall Effect

Implementation Method 2

generate a reference magnetic field signal responsive to a reference magnetic field

Methodology Applied

Scientific EffectMagnetic field sensing: Magnetoresistance

Data Source

PatentUS10451671B2Magnetic field sensor with shared path amplifier and analog-to-digital-converter

Publication Date: 2019.10.22 ALLEGRO MICROSYSTEMS LLC

AI summary

Methods and apparatus for processing a signal comprise at least one circuit configured to generate a measured signal during a measured time period and a reference signal during a reference time period. Also included is at least one dual- or multi-path analog-to-digital converter comprising at least a first processing circuit configured to process the measured signal, at least a second processing circuit configured to process the reference signal, and a third processing circuit configured to process both the measured signal and the reference signal.