Magnetic Sensor Eddy Current Cancellation for Transient Response
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional magnetic sensors suffer from deteriorated transient response characteristics due to eddy currents generated in lead frames, which cancel or interfere with the measurement target magnetic field, leading to overshooting and inaccurate detection.
Innovation Solution
A magnetic sensor design featuring a conductive substrate with a first region near the magnetic detection element generating a first magnetic field and a second region away from it, generating a second magnetic field that cancels the first, thereby improving transient response characteristics by preventing eddy currents from flowing between regions and ensuring accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a lead frame is used to support the semiconductor device, then the device structure is simple and easy to manufacture, but eddy currents are generated in the lead frame that cancel the measurement target magnetic field and deteriorate transient response characteristics
Solution Approach 1:
The conductive substrate is divided into multiple regions: a first region (die pad) that generates a first magnetic field from eddy currents, and a second region that generates a second magnetic field to cancel the first magnetic field. This segmentation allows the lead frame to maintain its structural support function while introducing a canceling mechanism through regional division of the conductive substrate.
Solution Approach 2:
Instead of eliminating eddy currents entirely, the invention utilizes the eddy current phenomenon itself by creating a second region that generates a canceling magnetic field. The harmful eddy current effect in the first region is converted into a beneficial cancellation mechanism through the second region, transforming the problem into a solution.
2Volume of moving object
If the semiconductor chip is thinned to achieve a low profile, then the device size is reduced, but the reliability may be compromised due to the proximity of the magnetic detection element to the conductive substrate
Solution Approach 1:
The conductive substrate is designed with different local properties: the first region (die pad) is positioned close to the magnetic detection element to generate the canceling magnetic field, while the second region is positioned away from it. This local differentiation allows the thinned chip structure to maintain reliability by ensuring the magnetic field cancellation occurs precisely where needed, despite the reduced distance between components.
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 proposed design enhances transient response characteristics by effectively canceling the first magnetic field with the second, reducing overshooting and improving the accuracy of magnetic field detection, while maintaining the reliability of the sensor even when the semiconductor chip is thinned for a low profile.
Implementation Method 1
a first region that is disposed in the vicinity of the magnetic detection element and generates a first magnetic field from a first eddy current generated by an application of a measurement target magnetic field
Implementation Method 2
a second region that is disposed away from the first region and generates a second magnetic field having an intensity that cancels the first magnetic field from a second eddy current
Data Source
AI summary
A magnetic sensor has a Hall IC that has a Hall element formed on a surface of the Hall IC, and a lead frame that supports the Hall IC. The lead frame includes a first region that is disposed in the vicinity of the Hall element and generates a first magnetic field due to a first eddy current generated when a measurement target magnetic field is applied, and second regions that are disposed away from the first region and generate a second magnetic field having an intensity that cancels the first magnetic field by means of second eddy currents generated when the measurement target magnetic field is applied.