Magnetic Field Sensor With Dual-Layer Galvanic Isolation

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Solution Overview

Problem

Existing current sensors face challenges in ensuring reliable galvanic isolation between the current rail and the magnetic field sensor, particularly in high-voltage applications, which can lead to potential current paths and reduced accuracy.

Innovation Solution

A current sensor design featuring a first and second insulation layer between the current rail and the magnetic field sensor, with an interface that is free of contact with both, utilizing materials with specific dielectric properties and thicknesses to enhance galvanic isolation and sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single insulation layer is used between the current rail and the magnetic field sensor, then the device complexity is reduced, but the reliability of galvanic isolation is insufficient

Engineering Contradiction:

Improvegalvanic isolation reliabilityVSAvoidinsulation structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The insulation structure is divided into multiple discrete insulation layers (first insulation layer and second insulation layer) rather than using a single continuous layer. This segmentation provides multiple independent barriers against electrical breakdown, enhancing galvanic isolation reliability while allowing each layer to be optimized for specific functions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite insulation structures combining different materials with complementary properties. The first insulation layer may use materials optimized for electrical insulation, while the second insulation layer provides additional protection and mechanical stability. This composite approach achieves superior galvanic isolation reliability compared to single-material solutions.

Inventive Principle:

Principle #40Composite materials

2Measurement precision

If the magnetic field sensor is positioned closer to the current rail, then the measurement sensitivity is improved, but the risk of current paths and galvanic isolation failure increases

Engineering Contradiction:

Improvecurrent measurement sensitivityVSAvoidcurrent path risk

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The multi-layer insulation structure acts as an intermediary barrier between the current rail and the magnetic field sensor. This intermediary insulation wall allows the sensor to be positioned close to the rail for high sensitivity while preventing direct electrical contact and harmful current paths through the insulation layers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

By segmenting the insulation into multiple layers, the patent creates multiple discrete barriers that maintain close proximity between the current rail and sensor while preventing electrical breakdown. Each insulation layer contributes to the overall isolation, enabling the sensor to operate close to the rail without direct contact.

Inventive Principle:

Principle #1Segmentation

3Reliability

If insulation layers are added to ensure galvanic isolation, then the reliability is improved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvegalvanic isolation reliabilityVSAvoidinterface contact precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The insulation layers are designed to self-align and self-secure through their material properties and structural configuration. The layers naturally conform to the current rail and sensor surfaces, providing reliable galvanic isolation without requiring complex precision alignment procedures or high-precision manufacturing tolerances for interface contacts.

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 design provides robust galvanic isolation, reducing the risk of current paths and improving accuracy and sensitivity, enabling reliable operation in high-voltage environments.

Implementation Method 1

a magnetic field sensor (102) configured to measure a magnetic field induced by a current flowing through the current rail (101)

Methodology Applied

Scientific EffectMagnetic field induction: Electromagnetic Induction

Implementation Method 2

a first insulation layer (103) and a second insulation layer (104) arranged between the current rail (101) and the magnetic field sensor (102)

Methodology Applied

Scientific EffectDielectric isolation: Dielectric

Data Source

PatentUS12366615B2Current sensor that includes a current rail and a magnetic field sensor with galvanic isolation

Publication Date: 2025.07.22 INFINEON TECHNOLOGIES AG

AI summary

A current sensor includes a current rail and a magnetic field sensor. The magnetic field sensor is configured to measure a magnetic field induced by a current flowing through the current rail. A first insulation layer and a second insulation layer are arranged between the current rail and the magnetic field sensor. An interface between the first insulation layer and the second insulation layer is free of a contact with the current rail and/or is free of a contact with the magnetic field sensor. A portion of the current rail extends into the second insulation layer and the portion of the current rail is encapsulated by the second insulation layer.