Hall Effect Sensor with Three Contacts for Zero-Point Error Reduction
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Solution Overview
Problem
Vertical Hall devices suffer from significant zero-point errors due to asymmetry, which existing methods, such as the spinning current scheme, fail to adequately address, resulting in residual errors of about 1 mT, and mechanical stress sensors face similar challenges in symmetry and contact resistance issues.
Innovation Solution
An electronic device with a Hall effect region and three contacts, where the first and third contacts are arranged symmetrically with respect to the second contact, allowing for improved electrical current distribution influenced by physical quantities, enabling more accurate sensing of magnetic fields and mechanical stress through a modified spinning current scheme.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a vertical Hall device uses the spinning current scheme to cancel zero-point error, then the offset behavior is improved, but residual zero point errors of about 1 mT remain due to asymmetry and contact resistances
Solution Approach 1:
The patent applies asymmetry principle by intentionally introducing a compensating asymmetry through the third contact to counterbalance the inherent asymmetry in the Hall device structure. The third contact is positioned at a specific location to create an asymmetric current distribution that compensates for the asymmetric contact resistances, thereby improving zero-point error cancellation beyond conventional symmetric four-contact designs
Solution Approach 2:
The patent changes the electrical parameters by introducing a third contact that allows for additional current path configuration. By adjusting the current distribution through the third contact and using it as a sense contact, the device achieves better offset behavior through modified electrical parameter relationships rather than relying solely on geometric symmetry
2Stability of the object's composition
If four vertical Hall devices are connected to improve symmetry, then the symmetry is enhanced, but contact resistances still cause residual asymmetries
Solution Approach 1:
The patent applies local quality principle by making the third contact serve dual functions: as a sense contact for measuring Hall voltage and as a means to locally adjust current distribution. This localized functional enhancement at the third contact position allows compensation for contact resistance asymmetries without requiring complete symmetry throughout the entire device structure
3Area of stationary object
If the third contact is positioned closer to the first and second contacts, then the device area is reduced, but the symmetry and sensing accuracy may be compromised
Solution Approach 1:
The patent applies dimensionality change by transitioning from a conventional linear arrangement of contacts to a two-dimensional configuration where the third contact is positioned at an optimized location in the plane. This spatial reconfiguration in another dimension allows the third contact to be closer to the first and second contacts while maintaining proper symmetry and sensing accuracy through geometric optimization
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 configuration significantly reduces zero-point errors and enhances the symmetry of the spinning current scheme, allowing for more precise measurement of magnetic fields and mechanical stress, improving the signal-to-noise ratio and reducing common mode signals.
Implementation Method 1
an electrical current distribution within the Hall effect region is influenced by a physical quantity to be measured and wherein a sense signal tapped at the third contact is a function of the current distribution
Data Source
AI summary
An electronic device is disclosed as a part of a magnetic field sensor or a mechanical stress sensor. The electronic device includes a Hall effect region, a first contact (temporarily functioning as a first supply contact), a second contact (second supply contact), and a third contact (temporarily functioning as a first sense contact) that are arranged in or on a surface of the Hall effect region. The first contact and the third contact are arranged in a substantially symmetrical manner to each other with respect to the second contact. An electrical current distribution within the Hall effect region is influenced by a physical quantity (e.g. magnetic field strength or mechanical stress) to be measured. A sense signal tapped at the third contact is a function of the current distribution, the sense signal thus being indicative of the physical quantity. A corresponding sensing method using the electronic device is also disclosed.