Pressure Sensor TCO Adjustment via Leadout Resistor Modification
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Solution Overview
Problem
Silicon-based pressure sensors often exhibit a temperature coefficient of offset voltage (TCO) that is not centered at zero due to mismatched resistors and variations in the assembly process, leading to inconsistent performance.
Innovation Solution
Adjusting the resistance of leadout and stress-induced resistors in a Wheatstone bridge circuit by changing their cross-sectional area or dimensions to shift the TCO distribution within a range of 0±4 microvolts per volt per degree Celsius, while maintaining the same offset voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard assembly process is used for pressure sensor, then manufacturing simplicity is maintained, but TCO distribution is not centered at zero leading to inconsistent performance
Solution Approach 1:
The patent applies preliminary action by adjusting the resistance of leadout resistors before final assembly to pre-position the TCO distribution centered at zero. This advance adjustment ensures consistent sensor performance without requiring complex post-assembly calibration processes, thereby improving reliability while controlling complexity.
Solution Approach 2:
The patent utilizes parameter changes by modifying the resistance values of leadout resistors within the Wheatstone bridge circuit. By changing this electrical parameter, the TCO distribution is shifted to be centered at zero, improving performance consistency without fundamentally altering the assembly process structure.
2Measurement precision
If resistor values are adjusted to center TCO distribution, then measurement accuracy is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by adjusting the resistance of leadout resistors to achieve TCO distribution centered at zero. This approach improves measurement precision by eliminating offset voltage drift while managing manufacturing precision through controlled resistance adjustments rather than requiring perfect resistor matching.
Solution Approach 2:
The leadout resistors serve as an intermediary element that mediates between the stress-induced resistors and the measurement circuit. By adjusting these intermediary resistors, the TCO distribution is centered without requiring the stress-induced resistors themselves to be perfectly matched, thereby improving measurement precision while relaxing manufacturing precision requirements.
3Measurement precision
If leadout resistor resistance is changed to adjust TCO, then TCO control precision is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the resistance values of leadout resistors to precisely control the TCO distribution. This achieves improved TCO control accuracy through electrical parameter adjustment rather than mechanical or structural modifications, thereby managing device complexity.
Solution Approach 2:
The patent applies self-service by using the existing leadout resistors within the Wheatstone bridge circuit to perform the TCO adjustment function. These resistors serve dual purposes: their standard function in the bridge circuit and their function as adjustment elements for centering TCO distribution, thereby improving control precision without adding separate adjustment mechanisms or increasing device complexity.
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 allows for precise control of TCO, improving the accuracy and reliability of pressure sensors by centering the TCO distribution, thereby enhancing their sensitivity and stability.
Implementation Method 1
Silicon-based pressure sensors typically comprise an arrangement of stress induced resistors in a Wheatstone bridge electrical circuit
Implementation Method 2
TCO will result. Additionally, the TCO may also be influenced by the assembly process
Data Source
AI summary
Embodiments relate generally to systems and methods for adjusting a temperature coefficient of the offset voltage (TCO) for a pressure sensor, the method comprising assembling the pressure sensor, wherein the sensor comprises a plurality of resistive elements; determining the TCO distribution for the sensor; increasing the resistance of one of a stress induced resistor or a leadout resistor of a first resistor; and decreasing the resistance of one of the stress induced resistor or the leadout resistor of the first resistor to adjust the TCO of the sensor.