Differential Sensor Stress Compensation Using Self-Service Circuitry
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Solution Overview
Problem
Differential sensors face inaccuracies due to mechanical stresses from components with different coefficients of thermal expansion, leading to inefficiencies and high costs in conventional stress compensation methods.
Innovation Solution
A differential sensor system with compensation circuitry that determines a compensation factor based on the stress difference between sensor elements, adjusting their output signals to account for stress-related mismatches, eliminating the need for additional stress-sensing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional stress compensation methods are used (special low-stress packages, low-stress die attach, mold compound, ceramic packaging), then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The sensor elements themselves are used to sense the mechanical stress affecting them, eliminating the need for separate stress-sensing components. The same sensor elements that measure the primary physical quantity also detect stress-induced changes, allowing the system to self-diagnose and self-correct for stress effects through the compensation circuitry.
Solution Approach 2:
The sensor elements perform dual functions: measuring the primary physical quantity (magnetic field, pressure, temperature, etc.) and simultaneously detecting mechanical stress. This multi-functionality eliminates the need for dedicated stress-sensing elements, simplifying the overall device structure while maintaining compensation capability.
2Measurement precision
If conventional stress compensation methods are used (special low-stress packages, low-stress die attach, mold compound, ceramic packaging), then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The sensor elements themselves are used to sense the mechanical stress affecting them, eliminating the need for separate stress-sensing components. The same sensor elements that measure the primary physical quantity also detect stress-induced changes, allowing the system to self-diagnose and self-correct for stress effects through the compensation circuitry.
Solution Approach 2:
The patent uses standard, inexpensive packaging materials and assembly methods rather than expensive specialized components. By using the sensor elements themselves for stress detection and applying electronic compensation, the system avoids the need for costly ceramic packaging, special low-stress die attach materials, and complex mold compounds, thereby reducing manufacturing costs.
3Measurement precision
If individual stress compensation for each sensor element is attempted, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines the stress sensing function with the primary sensing function by using the same sensor elements for both purposes. The compensation circuitry processes the differential output signals to extract stress information and applies correction factors, merging multiple compensation functions into a unified electronic system rather than requiring separate mechanical compensation mechanisms for each element.
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 approach simplifies and reduces the cost of stress compensation in differential sensors by using the sensor elements themselves to detect and correct for mechanical stress, providing accurate output signals without additional stress-sensing components.
Implementation Method 1
The change in the output signal versus a small change of input physical quantity is referred to as the sensor sensitivity (e.g., magnetic sensitivity, pressure sensitivity, etc.). This sensitivity also depends on mechanical stresses that act on the sensor elements.
Data Source
AI summary
Embodiments relate to stress compensation in differential sensors. In an embodiment, instead of compensating for stress on each sensor element independently, stress compensation circuitry aims to remove stress-related mismatch between two sensor elements using the sensor elements themselves to detect the mismatch. A circuit can be implemented in embodiments to detect mechanical stress-related mismatch between sensor elements using the sensor elements, and tune the output signal by a compensation factor to eliminate the mismatch. Embodiments are therefore less complicated and less expensive than conventional approaches. While embodiments have applicability to virtually any differential sensor, including magnetic field, pressure, temperature, current and speed, an example embodiment discussed herein relates to magnetic field.