Hall Sensor State Detection Circuit for Low-Power Remote Switches

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Solution Overview

Problem

Existing remotely operated switches, such as relays and contactors, face issues with reliability in detecting switching states, particularly in the presence of external magnetic fields, and have high power consumption, along with risks from reversed wiring and electrostatic discharge.

Innovation Solution

A state detection circuit with a Hall sensor connected between a voltage regulator and an output switch, incorporating diodes and capacitors for protection, allows operation over a wide voltage range and reduces current consumption, enhancing reliability and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a Hall sensor is used to detect switching state, then detection reliability is improved, but power consumption increases

Engineering Contradiction:
Improveswitching state detection reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the operating parameters of the Hall sensor by implementing intermittent measurement mode instead of continuous operation. The control unit activates the Hall sensor only when switching state detection is required, thereby maintaining detection reliability while dramatically reducing average power consumption of the sensor circuit

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system employs periodic action by using intermittent measurement cycles where the Hall sensor is activated only during specific time intervals when state detection is needed. This periodic activation pattern maintains system reliability while minimizing continuous power draw from the sensor

Inventive Principle:
Principle #19Periodic action

2Device complexity

If read contacts are used to communicate switching state, then device complexity is reduced, but reliability deteriorates in presence of external magnetic fields

Engineering Contradiction:
Improvecircuit complexityVSAvoidswitching state detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces the mechanical read contact system with a magnetic field-based Hall sensor detection system. This substitution eliminates mechanical wear and contact reliability issues while using magnetic field sensing that is less susceptible to external magnetic interference through proper shielding and differential measurement techniques

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system introduces a magnetic field as an intermediary between the mechanical switch state and the electronic detection circuit. The Hall sensor detects magnetic field changes caused by the switch position, providing an indirect but more reliable measurement method that avoids direct electrical contact issues

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If electronics are protected from reverse polarity and electrostatic discharge, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveelectronics reliabilityVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements protective components such as reverse polarity protection diodes and electrostatic discharge (ESD) protection circuits that are pre-installed in the circuit path. These components act as cushioning elements that absorb or divert harmful electrical transients before they can damage sensitive electronics, thereby improving reliability with minimal added complexity

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The protection circuitry is designed to automatically activate when reverse polarity or electrostatic discharge conditions are detected, without requiring external control or intervention. The protection mechanisms self-regulate to protect the electronics, maintaining simplicity while ensuring reliability

Inventive Principle:
Principle #25Self-service

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 new configuration supports reliable switching state detection with reduced power consumption and protection against reverse polarity and electrostatic discharge, making it universally applicable and compatible with existing switches without additional development.

Implementation Method 1

The state detection circuit (ZES) comprises a Hall sensor circuit (HSS) with a Hall sensor (HS)

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP4288989B1A state-detection circuit and remotely controllable switch
Publication Date: 2026.01.28 TDK ELECTRONICS AG
  • EP4288989B1 patent drawingFigure 1~2
  • EP4288989B1 patent drawingFigure 3~4
  • EP4288989B1 patent drawingFigure 5

AI summary

An improved state detection circuit having a reduced power consumption and an increased reliability is disclosed. The state detection circuit has a Hall sensor circuit which is connected between a voltage regulator and an output switch.