Hall Effect Circuit Stress Compensation via Epitaxial Resistor Bridge
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Solution Overview
Problem
Hall effect elements experience sensitivity drift due to substrate stress, which is not effectively compensated by existing technologies, leading to instability in magnetic field sensing applications.
Innovation Solution
An electronic circuit incorporating a resistor bridge with vertical and lateral epitaxial resistors, configured to sense substrate stress and generate a differential signal, which is used to compensate for the sensitivity changes in the Hall effect element through a compensation circuit and amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stable current source is used to maintain constant sensitivity, then the drive current stability is improved, but sensitivity drift due to substrate stress cannot be compensated
Solution Approach 1:
A resistor bridge circuit is introduced as an intermediary element that senses substrate stress and generates a compensation signal. This mediator detects the stress condition affecting the Hall effect element and produces a corresponding output that can be used to compensate for sensitivity drift, thereby resolving the contradiction between maintaining stable drive current and preserving measurement accuracy under stress conditions.
2Measurement precision
If temperature compensation is implemented, then temperature-induced sensitivity changes are corrected, but stress-induced sensitivity changes remain uncorrected
Solution Approach 1:
The resistor bridge circuit is designed to respond to substrate stress conditions that affect the Hall effect element's sensitivity. By configuring the bridge with appropriate resistive elements, it generates an output signal that compensates for stress-induced sensitivity drift, extending the compensation capability beyond temperature effects to include mechanical stress effects as well.
3Measurement precision
If a resistor bridge with epitaxial resistors is added to sense substrate stress, then stress-induced sensitivity drift is compensated, but device complexity increases
Solution Approach 1:
The resistor bridge circuit is integrated onto the same semiconductor substrate as the Hall effect element, merging the sensing function with the existing device structure. This integration approach allows stress sensing and compensation to be achieved without requiring separate discrete components, thereby minimizing the increase in device complexity while still providing effective sensitivity drift compensation.
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 solution effectively compensates for sensitivity drift caused by substrate stress, maintaining stable magnetic field sensing performance across varying temperature and stress conditions.
Implementation Method 1
Hall effect elements are known. A typical planar or horizontal Hall effect element is a four terminal device for which a drive current (a DC current) is passed between two opposing ones of the four terminals and a differential voltage (AC or DC), responsive to a magnetic field (AC or DC), is generated between the other two opposing ones of the four terminals.
Implementation Method 2
The resistor bridge can be operable to generate a differential signal responsive to a stress of the semiconductor substrate.
Data Source
Figure 1
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AI summary
The present disclosure is directed to an electronic circuit having a Hall effect element and a resistor bridge, all disposed over a common semiconductor substrate. The resistor bridge includes a first set of resistive elements having a first vertical epitaxial resistor and a first lateral epitaxial resistor coupled in series, and a second set of resistive elements having a second vertical epitaxial resistor and a second lateral epitaxial resistor coupled in series. The first set of resistive elements and the second set of resistive elements can be coupled in parallel. The resistor bridge can be configured to sense a stress value of the Hall effect element.