Differential Current Sensor Package for Low-Noise Fault Detection
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Solution Overview
Problem
Conventional current sensors struggle to accurately detect small current differences between two conductors, particularly in applications like ground fault interrupt circuits, leading to false trip points due to noise and current mismatches that do not represent actual faults.
Innovation Solution
A current sensor integrated circuit package with multiple magnetic field sensing elements and a processor that compensates for misalignment and noise, allowing precise detection of current differences between primary conductors, including configurations for parallel and redundant current paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional GFI current sensors are used to detect small current differences, then measurement precision is improved, but device complexity increases and false alarms occur due to limited sensitivity
Solution Approach 1:
The sensor is divided into multiple independent magnetic field sensing elements (first and second sensing elements) positioned at different locations. Each sensing element independently measures the magnetic field from its respective conductor, allowing the system to detect current differences without requiring a complex single-sensor configuration.
Solution Approach 2:
The patent introduces a processor as an intermediary component that receives magnetic field measurements from multiple sensing elements and calculates current differences. This intermediary processing approach simplifies the overall system by using simple sensing elements combined with computational analysis rather than requiring complex sensing hardware.
2Measurement precision
If conventional GFI sensors are used, then current difference detection is attempted, but reliability decreases due to false alarms in motor applications
Solution Approach 1:
The patent positions magnetic field sensing elements at specific locations relative to each conductor (first sensing element near first conductor, second sensing element near second conductor). This localized measurement approach allows the system to detect actual current differences in motor applications while avoiding false alarms by measuring magnetic fields at optimal positions that reflect true current imbalance.
Solution Approach 2:
The processor continuously monitors magnetic field measurements from both sensing elements and compares them to detect current differences. This feedback mechanism allows the system to dynamically identify when a genuine current imbalance exists (such as in motor faults) versus when normal operational variations occur, thereby improving reliability.
3Measurement precision
If multiple magnetic field sensing elements are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple magnetic field sensing elements (first and second sensing elements) with a processor in a single integrated current sensor package. This merging approach allows the system to achieve high measurement precision through multiple sensing elements while avoiding the complexity of separate distributed sensors, as all components are integrated into one unit.
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
Enables accurate detection of current mismatches beyond typical GFI thresholds, reducing false alarms and improving system reliability by distinguishing between legitimate faults and normal operational conditions.
Implementation Method 1
as current in a first primary current path generates a first magnetic field, and a second primary current path generates a second magnetic field
Implementation Method 2
magnetic field sensing elements, which may comprise a planar Hall element, a vertical Hall element
Implementation Method 3
magnetoresistance element, such as a giant magnetoresistance element (GMR), a tunneling magnetoresistance element (TMR) or a magnetic tunnel junction (MTJ)
Data Source
Figure 1
Figure 1A~1B
Figure 2
AI summary
Methods and apparatus for measuring a current difference between at least two primary current paths in a current sensor integrated circuit package. Each primary current path generated a magnetic field which may then be measured by at least one magnetic field sensing element positioned on an integrated circuit die. An output disconnect signal may be provided from the current sensor integrated circuit package when a current difference above a predetermined threshold exists in the two or more current traces.