Pressure Sensor Self-Calibration Using Integrated Heating
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Solution Overview
Problem
Pressure sensors face challenges with inaccurate and time-consuming calibration, especially after reflow soldering, and are prone to drift in harsh environments, requiring additional components for diagnostics.
Innovation Solution
A pressure sensor with integrated temperature coefficients and a built-in heating element that recalibrates in-system by heating the piezo resistive element, allowing for real-time compensation of temperature dependencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods are used, then calibration accuracy can be achieved, but calibration time and costs increase significantly
Solution Approach 1:
The pressure sensor performs self-calibration by automatically heating its own piezo resistive element using an integrated heating element, eliminating the need for external calibration equipment and reducing calibration time while maintaining accuracy through automated temperature coefficient updates
2Measurement precision
If traditional calibration methods are used, then calibration accuracy can be achieved, but additional components and equipment are required
Solution Approach 1:
The heating element is integrated directly into the sensor die along with the piezo resistive element, combining the calibration actuator and sensor into a single unit. This eliminates external calibration equipment and reduces the number of separate components needed for the calibration process
Solution Approach 2:
The integrated heating element serves dual purposes: it functions as both a temperature control element for the sensor and a calibration actuator for updating temperature coefficients, eliminating the need for separate calibration-specific components
3Stability of the object's composition
If temperature compensation is not updated, then device stability is maintained, but measurement accuracy deteriorates due to drift
Solution Approach 1:
The system implements a feedback mechanism where the processor continuously monitors the piezo resistive element's response and automatically updates temperature coefficients when drift is detected, maintaining both stability and accuracy through adaptive recalibration
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 reduces calibration time and costs while improving accuracy and reliability by enabling in-system updates of temperature coefficients, minimizing drift, and detecting malfunctions early.
Implementation Method 1
transmitting, to the built-in heating element, after receiving the first output signal, a heating signal for heating the pressure circuitry to a second temperature
Implementation Method 2
A pressure sensor can use a piezo resistive element, also called a piezo resistive gauge. The pressure creates stress in the material, and thus, when pressure is applied to the pressure sensitive element, its resistance changes due to the stress
Data Source
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AI summary
Herein is discussed a method carried out by a processor (300) for compensating temperature dependencies of a piezo resistive element (122) integrated in a pressure sensor (10), the method comprising the steps of: receiving, from the temperature circuitry (140), a first temperature signal for determining a first temperature (T1) of the pressure circuitry (120); receiving, from the sensor die (100), a first output signal for determining a first resistive value (R1T=T1) of the piezo resistive element at the first temperature (T1); transmitting, to the built-in heating element (160), after receiving the first output signal, a heating signal for heating the pressure circuitry (120) to a second temperature (T2); receiving, from the sensor die (100) after termination of the heating, a second output signal for determining a second resistive value (R1T=T2 of the piezo resistive element (120) at the second temperature (T2); and storing, in the memory (200), an updated TC for the piezo resistive element (122) calculated based on the first temperature (T1), the first resistive value (R1T=T1), the second temperature (T2), and the second resistive value (R1T=T2).