PCB Magnetic Circuit for Current Rise Detection

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Solution Overview

Problem

Existing circuit configurations for current measurement and current increase detection in electrical systems are either complex or inaccurate, and they often require expensive and complicated evaluation hardware.

Innovation Solution

A simple magnetic circuit using magnetically conductive elements and printed circuit boards, where measuring coils detect flux changes to provide high-quality, current-proportional signals without the need for expensive amplifiers, and the circuit board acts as a defined gap in the magnetic circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If ohmic shunts are used for current measurement, then current can be measured with a simple circuit, but the measurement signal is small and requires additional amplifier circuits

Engineering Contradiction:

Improvecircuit complexityVSAvoidsignal amplitude

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces ohmic measurement (electrical resistance-based) with magnetic measurement principles. Instead of measuring voltage drop across a resistor, the invention uses magnetically conductive elements and measuring coils to detect current through magnetic flux, eliminating the need for additional amplifier circuits while providing sufficient measurement signal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If Transfo-Shunts are used for current measurement, then floating current measurement is achieved, but the device becomes very expensive

Engineering Contradiction:

Improvefloating measurement capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive Transfo-Shunt components with inexpensive printed circuit board elements. The magnetically conductive elements are integrated directly into the PCB using standard manufacturing processes, eliminating the need for separate expensive current sensor components while maintaining floating measurement capability.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent combines the current measurement function with the printed circuit board structure itself. The magnetically conductive elements and measuring coils are integrated into the PCB, merging the structural support function with the measurement function, thereby reducing component count and manufacturing cost.

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If Rogowski coils are used for current increase measurement, then current change detection is achieved, but the geometrical arrangement becomes complicated

Engineering Contradiction:

Improvecurrent increase detectionVSAvoidgeometrical arrangement

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the complex three-dimensional Rogowski coil geometry with a planar printed circuit board implementation. The magnetically conductive elements and measuring coils are arranged in two dimensions on the PCB, maintaining current change detection capability while dramatically simplifying the geometrical arrangement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Ease of manufacture

If simple magnetically conductive elements are used, then manufacturing cost is reduced, but measurement accuracy may be compromised

Engineering Contradiction:

Improvemanufacturing costVSAvoidmeasurement accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent uses composite magnetic circuit structures combining magnetically conductive elements with the printed circuit board material. This composite approach maintains measurement accuracy by providing proper magnetic flux paths while using inexpensive, easily manufacturable materials and standard PCB fabrication processes.

Inventive Principle:

Principle #40Composite materials

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 solution enables accurate and economical detection of current increases in conductors on printed circuit boards, reducing complexity and costs while providing reliable, high-quality signals for current measurement and monitoring applications.

Implementation Method 1

the measuring coils detecting the flux increases of the current increases to be measured in the printed conductors as coil voltages

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a simple magnetic circuit is provided using magnetically conductive, preferably geometrically simple elements

Methodology Applied

Scientific EffectMagnetic conduction: Magnetism

Data Source

PatentEP3314274B1Circuit arrangement for the detection of at least two current rises

Publication Date: 2022.07.27 SCHRODL MANFRED

Figure 1~2
Figure 3~4

AI summary

The invention relates to a circuit arrangement and a method for detecting at least one current rise in at least one conductor (5, 6, 7) mounted on a printed circuit board. The arrangement is provided with a simple magnetic circuit (1), using magnetically conductive elements of a preferably simple geometric shape, and encloses the electrical conductors (5, 6, 7) to be measured. The magnetic circuit (1) uses the printed circuit board as a gap (4). At least one printed measuring coil (8, 9, 10, 11) is arranged in the region of the magnetic circuit (1). Said measuring coil (8, 9, 10, 11) detects the flow increase of the current increase to be measured in the conductor (5, 6, 7) as a coil voltage. An evaluation circuit (12) of measurement technology is provided and is connected to the measuring coil (8, 9, 10, 11).