Pressure Sensor On-Board Compensation for Thermal Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pressure sensors face errors and offsets due to mechanical stresses and temperature variations, particularly from mismatches in thermal expansion coefficients between the substrate and pressure sensing die, which affect the accuracy of their electrical output signals.
Innovation Solution
Incorporating an on-board heating element and a zener diode trim network on the pressure sensing die, which allows for temperature-induced errors to be identified and compensated by adjusting the resistive network, thereby improving the accuracy and precision of the pressure sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pressure sensor uses a substrate and pressure sensing die with mismatched thermal expansion coefficients, then the device can be manufactured with standard materials, but temperature-dependent mechanical stresses induce errors and offsets in the electrical output signal
Solution Approach 1:
The patent applies thermal stress compensation techniques that convert the harmful temperature-dependent mechanical stresses into a compensatable parameter. By characterizing the stress behavior and implementing compensation algorithms, the system transforms the inherent material mismatch problem into a manageable correction factor, maintaining both manufacturability and measurement precision.
Solution Approach 2:
The patent implements temperature compensation by monitoring temperature parameters and applying correction factors to the electrical output signal. This involves changing the operational parameters of the sensor system to account for thermal expansion mismatches, thereby maintaining signal accuracy across varying temperature conditions while using standard materials.
2Measurement precision
If on-board compensation components are added to the pressure sensing die, then temperature and stress induced errors can be compensated, but the device complexity increases
Solution Approach 1:
The patent integrates the compensation functionality directly into the pressure sensing die by forming compensation structures from the same piezoresistive material layer. This merging approach combines the sensing and compensation functions into a single integrated structure, reducing device complexity while maintaining signal accuracy through on-board temperature and stress compensation.
3Productivity
If compensation methods are implemented, then manufacturing yield can be improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent implements compensation structures during the initial fabrication process by forming compensation piezoresistive elements from the same material layer as the sensing elements. This preliminary action incorporates compensation functionality into the base manufacturing process, improving manufacturing yield without significantly complicating the manufacturing process.
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 stress and temperature-induced errors, enhancing the accuracy, yield, and performance of pressure sensors by allowing for real-time trimming and calibration of electrical parameters.
Implementation Method 1
The on-board heating element may be configured to heat the pressure sensor assembly to various temperatures so that temperature related offsets and/or errors may be identified
Implementation Method 2
pressure sensors may detect a pressure via a sensing element, often formed on a pressure sensing die, which converts mechanical stress caused by an incoming pressure into an electrical output signal
Implementation Method 3
The zener diode trim network may include one or more zener diodes and one or more resistive elements, where the zener diodes can be selectively activated to 'trim' the resistive network to compensate for one or more offsets and/or errors of the pressure sensor
Data Source
AI summary
The present disclosure relates generally to pressure sensors, and more particularly, to methods and apparatus for compensating pressure sensors for stress, temperature and/or other induced offsets and/or errors. In one illustrative embodiment, a pressure sensor may include a pressure sensing die mounted to a substrate of a pressure sensor package. The pressure sensor die may include on-board compensation. In some instances, the on-board compensation may include an on-board heating element and an on-board zener diode trim network, both situated on or in the pressure sensing die. The zener diode trim network may include one or more zener diodes and one or more resistive elements, where the zener diodes can be selectively activated to “trim” the resistive network to compensate for one or more offsets and/or errors of the pressure sensor. The on-board heating element may be configured to heat the pressure sensor assembly to various temperatures so that temperature related offsets and/or errors may be identified, and then compensated for with the zener diode trim network.