Magnetic Field Sensor Compensation Loop for Transient Signal Reduction

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Solution Overview

Problem

Magnetic field sensors, particularly current sensors, experience transient glitches when exposed to rapidly changing magnetic fields, which existing techniques struggle to mitigate without slowing down the desired edge rate of the output signal.

Innovation Solution

The magnetic field sensor incorporates a compensation loop with a conductive path that traverses in an opposite direction to the circuit loop, ensuring the compensation loop's interior area and rotation direction reduce overshoot or undershoot in the output signal, effectively canceling or minimizing transient signals during rapid magnetic field changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If filters are employed to remove transient glitches, then the unwanted glitch is removed, but the desired edge rate is slowed down

Engineering Contradiction:
Improvetransient glitchVSAvoidedge rate
Core Design Contradiction:
Object-affected harmful factorsVSSpeed

Solution Approach 1:

The patent converts the harmful transient signal generated by the circuit loop into a beneficial compensation signal by introducing a compensation loop that generates an equal but opposite transient signal, thereby canceling the original glitch without affecting the desired signal edge rate

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

Solution Approach 2:

The compensation loop is designed to generate a compensating transient signal in advance that opposes and cancels the unwanted transient signal from the circuit loop, preventing the glitch from appearing in the final output while maintaining signal integrity

Inventive Principle:
Principle #9Preliminary anti-action

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

This configuration significantly reduces or eliminates unwanted transient signals in the output of magnetic field sensors when encountering rapidly changing magnetic fields, maintaining the desired edge rate without the need for filters that slow down the response.

Implementation Method 1

a compensation loop coupled in a series arrangement with the circuit loop... The compensation loop interior area and the compensation loop rotation direction are selected to result in a reduction of an overshoot or an undershoot of an output signal... resulting from the circuit loop experiencing a rapid change in flux of the magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2609442B1Apparatus and method for reducing a transient signal in a magnetic field sensor
Publication Date: 2014.04.16 ALLEGRO MICROSYSTEMS LLC
  • EP2609442B1 patent drawingFigure 1
  • EP2609442B1 patent drawingFigure 2~2A
  • EP2609442B1 patent drawingFigure 3~3A

AI summary

A magnetic field sensor includes a compensation loop coupled in series with normal circuit couplings in order to reduce a transient signal that would otherwise be generated when the magnetic field sensor experiences a high rate of change of magnetic field. In some embodiments, the magnetic field sensor is a current sensor responsive to a magnetic field generated by a current-carrying conductor.