Vertical Hall Element Offset Voltage Removal via Asymmetric Heat Source Placement
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Solution Overview
Problem
Vertical Hall elements face challenges in accurately removing offset voltage due to non-uniform temperature distributions caused by heat sources, which affect the spinning current method's effectiveness.
Innovation Solution
The semiconductor device is designed with a heat source circuit positioned such that the center of the highest temperature region lies on a straight line intersecting the current paths of the vertical Hall element, ensuring symmetric heat transfer and consistent current flow directions, thereby enabling high-accuracy offset voltage removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a heat source circuit is provided around the vertical Hall element, then the vertical Hall element can be driven with sufficient power, but a temperature distribution occurs causing thermoelectric current that reduces offset voltage removal accuracy
Solution Approach 1:
The patent applies asymmetry by intentionally positioning the heat source circuit asymmetrically relative to the vertical Hall element. Specifically, the heat source is placed such that its center aligns with the center line of the Hall element along the current flow direction, creating a symmetric temperature distribution only in the direction perpendicular to current flow. This controlled asymmetric placement ensures that thermoelectric currents generated in opposite directions during spinning current method are equal, enabling accurate offset voltage removal while maintaining necessary drive power.
2Measurement precision
If the spinning current method is used to remove offset voltage, then offset voltage can be reduced, but temperature distribution from heat sources causes unequal current flow in different directions reducing effectiveness
Solution Approach 1:
The patent applies local quality by creating a specific thermal environment around the vertical Hall element. The heat source circuit is positioned to generate a temperature distribution that is symmetric with respect to the Hall element's current path. This localized thermal symmetry ensures that while temperature varies across the device, the thermoelectric effects are balanced in opposite directions, maintaining reliable and consistent current flow characteristics necessary for accurate spinning current method operation.
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 configuration ensures that the offset voltage can be removed with high accuracy despite temperature distributions, improving the reliability of the spinning current method in vertical Hall elements.
Implementation Method 1
there have been proposed various magnetic sensors that use a vertical Hall element configured to detect magnetic field component parallel to the substrate surface
Implementation Method 2
a temperature distribution occurs in the vertical Hall element, then a thermoelectric current constantly flows from a high-temperature portion to a low-temperature portion
Data Source
AI summary
A semiconductor device includes a vertical Hall element provided in a first region of a semiconductor substrate, and having the first to the third electrodes arranged side by side in order along a first straight line; a circuit provided in a second region of the semiconductor substrate different from the first region, and having a heat source; and a second straight line intersecting orthogonally a current path for a Hall element drive current which flows between the first electrode and the third electrode. The second line passes a center of the vertical Hall element, and a center point of a region which reaches the highest temperature in the circuit during an operation of the vertical Hall element lies on the second straight line.