Dual-Range Current Sensor Using Vertical Hall Element
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current sensors with horizontal Hall elements saturate at high currents, leading to measurement inaccuracies beyond their nominal range, and existing solutions for high-current applications are either expensive or prone to hysteresis errors due to ferromagnetic material saturation.
Innovation Solution
A current sensor design incorporating both horizontal and vertical Hall elements, where the magnetic field is deflected by 90° using a magnetic field concentrator, allowing the vertical Hall element to provide a monotonic Hall voltage even when the concentrators are saturated, enabling a dual-range measurement with high sensitivity in the nominal range and lower sensitivity in an overload range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If horizontal Hall elements are used in the air gap between magnetic field concentrators, then high measurement accuracy is achieved in the nominal range (0-50A), but the sensor saturates at high currents (above 100A) leading to loss of measurement capability
Solution Approach 1:
The sensor is divided into two functional parts: horizontal Hall elements for high-precision measurement in the nominal range and a vertical Hall element for detecting overload conditions. This segmentation allows each element to specialize in different current ranges, resolving the contradiction between precision and range.
Solution Approach 2:
The vertical Hall element acts as an intermediary indicator that activates when the horizontal Hall elements saturate. It provides a monotonic response that continues to increase with current beyond the nominal range, enabling the sensor to detect overload conditions without the horizontal elements being saturated.
2Adaptability or versatility
If ferromagnetic yoke with C-shape geometry is used to enclose the current conductor, then high-current measurement capability is achieved, but hysteresis effects occur at excessive magnetic saturation resulting in unacceptable measurement errors
Solution Approach 1:
The patent replaces the ferromagnetic yoke structure with a non-magnetic air gap structure. The magnetic field concentrators are made of non-magnetic material, eliminating the ferromagnetic saturation and hysteresis effects that plague traditional C-shape designs, while still enabling high-current measurement through the vertical Hall element.
3Adaptability or versatility
If two separate current sensors are combined to cover both measuring range and overload range, then complete measurement coverage is achieved, but the solution becomes expensive and requires matching sensitivities of individual sensors
Solution Approach 1:
The patent merges the functions of two separate sensors into a single integrated sensor chip. The horizontal Hall elements provide the first sensor function for nominal range measurement, while the vertical Hall element provides the second sensor function for overload detection. This integration eliminates the need for multiple separate sensors and their sensitivity matching.
4Measurement precision
If magnetic field concentrators are saturated at current limit, then the measurement signal remains constant above the predefined current limit, but this prevents detection of higher currents (1000A-2000A)
Solution Approach 1:
The patent introduces a dynamic response mechanism where the measurement characteristic changes based on the current magnitude. Below the nominal range, the horizontal Hall elements provide high-sensitivity linear response. Above the nominal range, the vertical Hall element activates, providing a different monotonic response that continues to increase with current, enabling dynamic adaptation to different measurement ranges.
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 dual-range current sensor provides accurate measurements with high resolution in the nominal range (0-50A) and lower accuracy but usable measurements in the overload range (200A-1000A), reducing costs and eliminating the need for multiple sensors, while minimizing technology-related offset voltages through the spinning current method and time-division multiplexing.
Implementation Method 1
The at least one magnetic field concentrator deflects the magnetic field locally by 90°
Implementation Method 2
at least one Hall element located near the edge of the at least one magnetic field concentrator
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
The sensor has magnetic field concentrators (2, 3) arranged on an upper side of a semiconductor chip (1), where the concentrators are separated by an air gap (4). Horizontal Hall elements (5, 6) are integrated in the chip, and the chip has a vertical hall element (8) arranged below the gap between the horizontal elements. The vertical element always provides monotonous Hall voltage that increases with an external magnetic field independent of whether the concentrators are magnetically saturated or not. An electronic circuit operates the elements and evaluates voltage signals of the elements.