Magnetic Field Sensor Fault Detection Using Switch Control

Solution Overview

Problem

Conventional magnetic field sensors in safety-critical applications require redundant sensors to detect faults, which increases costs due to the need for additional chip area.

Innovation Solution

A magnetic field sensor device incorporating a spinning current technique using switches to apply and measure currents across different terminals, allowing for fault detection through evaluation of measurement signals and providing error information without the need for redundant sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant magnetic field sensors are provided to detect faults, then reliability is improved, but device complexity and chip area increase

Engineering Contradiction:

Improvefault detection capabilityVSAvoidsensor quantity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The magnetic field sensor performs self-diagnosis by using its own internal switches as test objects. The control circuit applies test currents through the switches and evaluates the measurement signals to detect faults, allowing the sensor to monitor its own operational status without requiring external redundant sensors.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The switches in the magnetic field sensor serve dual functions: they are both operational components for normal sensor function and test objects for fault detection. The same switches used in regular operation are evaluated during self-diagnosis, eliminating the need for separate redundant sensor structures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If redundant magnetic field sensors are provided to detect faults, then reliability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvefault detection capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The magnetic field sensor performs self-diagnosis by using its own internal switches as test objects. The control circuit applies test currents through the switches and evaluates the measurement signals to detect faults, allowing the sensor to monitor its own operational status without requiring external redundant sensors.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Instead of creating physical redundant sensors, the system uses signal copying and evaluation - the measurement signals from the switches are copied and analyzed by the control circuit to detect faults, providing a virtual redundancy that eliminates the need for duplicate physical sensor structures.

Inventive Principle:

Principle #26Copying

3Reliability

If redundant magnetic field sensors are provided to detect faults, then reliability is improved, but chip area increases

Engineering Contradiction:

Improvefault detection capabilityVSAvoidchip area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The magnetic field sensor performs self-diagnosis by using its own internal switches as test objects. The control circuit applies test currents through the switches and evaluates the measurement signals to detect faults, allowing the sensor to monitor its own operational status without requiring external redundant sensors.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The diagnostic function is merged with the operational function - the same switches and circuitry used for normal sensor operation are also used for fault detection. The control circuit integrates both operational control and diagnostic evaluation, eliminating the need for separate redundant sensor structures and reducing chip area.

Inventive Principle:

Principle #5Merging (Combining)

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 solution enables effective fault detection in magnetic field sensors, reducing the requirement for redundant sensors and maintaining functional safety while minimizing additional chip area and costs.

Implementation Method 1

a magnetic field sensor, wherein switches associated with the magnetic field sensor are used to provide error information

Methodology Applied

Scientific EffectMagnetic field detection: Hall Effect

Data Source

PatentUS11346913B2Magnetic field sensor

Publication Date: 2022.05.31 INFINEON TECHNOLOGIES AG

AI summary

Devices and methods are provided where switches associated with a magnetic field sensor are used to provide error information. In particular, a device is provided that includes a magnetic field sensor, a plurality of switches associated with the magnetic field sensor, and a control circuit configured to control the plurality of switches and to provide at least one signal indicative of a fault based on operation of the switches.