Magnetic field sensor apparatus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic field sensor apparatuses face interference from eddy currents when using conductive leadframes, which impair measurement accuracy and bandwidth, especially when measuring high-frequency magnetic fields.
Innovation Solution
The magnetic field sensor apparatus includes a chip with a magnetic field sensor and a coil arranged within a cutout of a conductive leadframe or a non-conductive carrier, ensuring that at least 75% of the sensor's sensitive area and 25% of the coil's area lie within the cutout, thereby minimizing eddy currents and enhancing measurement accuracy and bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive leadframe is used to mount the chip, then electrical connections are established and mechanical support is provided, but eddy currents arise that impair magnetic field measurements
Solution Approach 1:
The leadframe is segmented by introducing cutouts that divide the conductive material into separate regions. This segmentation interrupts the continuous conductive paths that would otherwise allow eddy currents to form, thereby reducing the harmful eddy current effects while maintaining the leadframe's structural and electrical connection functions.
Solution Approach 2:
Conductive material is removed from specific regions of the leadframe by creating cutouts. This extraction of material eliminates the portions that would generate eddy currents, while preserving the necessary conductive paths for electrical connections. The cutouts strategically remove only the harmful conductive regions.
2Productivity
If the coil and magnetic field sensor are positioned to maximize measurement coverage, then measurement bandwidth is improved, but eddy current interference increases
Solution Approach 1:
The leadframe is designed with non-uniform conductivity distribution through strategically placed cutouts. Regions beneath the coil and magnetic field sensor have cutouts to eliminate eddy currents, while other regions maintain conductivity for electrical connections. This local differentiation allows the sensor components to be positioned for maximum measurement coverage without generating harmful eddy currents in critical areas.
3Measurement precision
If a larger area of the magnetic field sensor is placed within the coil area, then measurement sensitivity is improved, but the impact of eddy currents from the leadframe increases
Solution Approach 1:
Cutouts in the leadframe segment the conductive material to prevent eddy current formation directly beneath the magnetic field sensor's sensitive area. This allows the sensor to be positioned with maximum overlap with the coil area for enhanced sensitivity, while the segmented leadframe structure eliminates the eddy current interference that would otherwise degrade measurement precision.
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 arrangement effectively suppresses eddy currents, improving the accuracy and bandwidth of magnetic field measurements across a wide frequency range, including static and high-frequency fields, while maintaining low noise and high linearity.
Implementation Method 1
a coil, wherein the coil and the magnetic field sensor are arranged in such a way that in the case of an orthogonal projection of the magnetic field sensor onto a plane defined by the turns of the coil
Implementation Method 2
a chip, wherein the chip comprises a magnetic field sensor and a coil
Implementation Method 3
In a leadframe of this type, eddy currents can arise, however, which impair the magnetic field measurements by means of the Hall sensor and/or the coil
Data Source
AI summary
Magnetic field sensor apparatuses are discussed. A magnetic field sensor apparatus in accordance with one example implementation in this case comprises a coil and a magnetic field sensor. A chip carrying the coil and the magnetic field sensor is arranged on a leadframe. The leadframe comprises a cutout.