Differential PCB Current Sensing for Compact Leakage Detection

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Solution Overview

Problem

Existing leakage current sensors are bulky and expensive, and they struggle to accurately measure small current differences, which is crucial for safety in systems like solar energy applications.

Innovation Solution

A compact current sensing system using semiconductor dies with magnetic field sensing elements placed equidistantly and symmetrically from conductors, generating output signals based on the difference between sensed magnetic fields, and employing differential operational amplifiers to calculate current differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional leakage current sensors are used, then they can detect leakage currents, but they are bulky and expensive

Engineering Contradiction:

Improveleakage current detection capabilityVSAvoidsensor size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent combines multiple magnetic field sensing elements (first and second sensing elements) into a single integrated sensor system that detects leakage current through differential measurement. This merging approach maintains detection capability while reducing overall sensor size and cost compared to traditional separate sensing components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The sensor divides the measurement function into separate magnetic field sensing elements positioned at different locations (first sensing element near first conductor, second sensing element near second conductor). Each element measures magnetic fields independently, and their differential output provides leakage current detection with improved precision and reduced size.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If traditional leakage current sensors are used, then they can detect leakage currents, but they are expensive

Engineering Contradiction:

Improveleakage current detection capabilityVSAvoidsensor cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The sensor uses identical or similar magnetic field sensing elements positioned symmetrically at different locations. The second sensing element is a copy of the first, positioned near the second conductor, allowing differential measurement that cancels common-mode interference and improves measurement precision without requiring expensive specialized components.

Inventive Principle:

Principle #26Copying

3Measurement precision

If magnetic field sensing elements are placed equidistantly and symmetrically from conductors, then sensitivity to current differences improves, but device complexity increases

Engineering Contradiction:

Improvesensitivity to current differencesVSAvoidsensor configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses symmetric positioning of sensing elements relative to conductors (first sensing element near first conductor, second sensing element near second conductor, both equidistant from their respective conductors). This symmetric configuration enhances sensitivity to differential currents while the differential measurement approach automatically rejects common-mode signals, improving precision without excessive complexity.

Inventive Principle:

Principle #4Asymmetry

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 system provides accurate and efficient detection of leakage currents with improved sensitivity and reduced size, addressing the limitations of traditional sensors.

Implementation Method 1

The first magnetic field sensing element may be configured to sense a first magnetic field associated with a first current through a first conductor

Methodology Applied

Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 2

The first and second magnetic field sensing elements may comprise one or more magnetoresistive elements or Hall effect elements

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS20250355025A1Current sensor systems

Publication Date: 2025.11.20 ALLEGRO MICROSYSTEMS LLC

AI summary

Provided are compact current sensing systems based on printed circuit boards (PCB) and/or integrated circuits (IC). Sensors are configured to detect or sense a current, such as a leakage current. Semiconductor die supporting magnetic field sensing elements are placed equidistantly and symmetrically from one or more conductors to sense a current in the conductor. A circuit may output a signal based on a difference between the outputs of the sensing elements.