Core-Based Current Sensors With Integrated Coils for Closed-Loop Compensation
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Solution Overview
Problem
Closed-loop core-based current sensors require a cumbersome and costly process to loop a coil around the core for compensation, resulting in a larger footprint and increased complexity compared to open-loop sensors.
Innovation Solution
Integration of a compensation coil with the substrate and magnetic field sensor within the magnetic core, allowing for closed-loop operation without the need for a separate coil loop, thereby simplifying the manufacturing process and reducing cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a coil is looped around the magnetic core to provide compensation field, then closed-loop operation and measurement accuracy are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the compensation coil with the magnetic core by integrating the coil windings directly onto the core structure. This merging eliminates the need for separate, externally looped coils while maintaining the closed-loop compensation function, thereby reducing device complexity and manufacturing cost while preserving measurement accuracy.
2Reliability
If a coil is looped around the magnetic core for compensation, then closed-loop operation is achieved, but manufacturing process becomes cumbersome and costly
Solution Approach 1:
The compensation coil is merged with the magnetic core structure, allowing both components to be manufactured as an integrated unit. This integration simplifies the manufacturing process by eliminating separate assembly steps required for externally looped coils, making the device easier and less costly to manufacture while maintaining reliable closed-loop operation.
3Measurement precision
If a separate compensation coil is used, then measurement accuracy is improved, but footprint and complexity increase
Solution Approach 1:
The compensation coil is nested within or onto the magnetic core structure, with the coil windings integrated directly into the core geometry. This nesting approach allows the compensation function to be embedded within the existing core footprint, eliminating the need for additional external space and reducing the overall device footprint while maintaining measurement accuracy.
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 integrated coil configuration provides high bandwidth and accuracy similar to prior-art techniques while reducing complexity and cost, maintaining performance without magnetic core saturation.
Implementation Method 1
a magnetic field sensor connected to, e.g., disposed in, an integrated circuit (IC) and supported by a substrate, where the magnetic field sensor is configured to receive magnetic flux from the gap
Implementation Method 2
The magnetic field sensor may include one or more Hall effect elements
Implementation Method 3
a coil integrated with the substrate and coupled to the IC, where the coil is configured to provide negative magnetic feedback for closed-loop compensation
Implementation Method 4
the secondary current, I S , effectively creates a flux equal in amplitude, but opposite in direction, to the flux created by the primary current
Implementation Method 5
This field is concentrated by the magnetic core 101 and the magnetic flux density across the gap is measured by the magnetic field sensor 105
Implementation Method 6
The magnetic core may include a soft ferromagnetic material
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Systems, circuits, and methods provide core-based closed-loop current sensors (200) utilizing a coil (208) connected to an IC having a magnetic field sensor (204) configured to measure current in one or more conductors such as busbars (202a-b). A closed-loop current sensor (200) includes a magnetic core (201) having first and second ends separated by a gap (201a) and an aperture receiving the one or more conductors; a magnetic field sensor (204) disposed on a substrate (206) and integrated in an IC is disposed in the gap (201a), where the magnetic field sensor (204) is configured to receive magnetic flux from the gap (201a), where the IC is configured to measure AC current in the one or more conductors; and a coil (208) integrated with the substrate (206) and coupled to the IC, wherein the coil (208) is configured to provide negative magnetic feedback for closed-loop compensation.