Pressure Sensor Self-Heating Calibration for Temperature Drift
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Solution Overview
Problem
Pressure sensors face challenges with inaccurate calibration due to temperature dependencies, which are time-consuming and costly, and require additional components for self-compensation, especially in harsh environments.
Innovation Solution
Integrate a built-in heating element with the pressure sensor to recalibrate temperature coefficients in-system by heating the piezo resistive element, using the same resistors for both heating and temperature measurement, and store updated coefficients for compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods are used for pressure sensors, then measurement accuracy can be achieved, but calibration time and costs increase significantly
Solution Approach 1:
The pressure sensor performs self-calibration by automatically measuring its own temperature-dependent resistance characteristics using integrated temperature sensors and piezo resistive elements, eliminating the need for external calibration equipment and manual procedures while maintaining measurement accuracy
Solution Approach 2:
The system measures resistance values at different temperatures and calculates temperature coefficients to compensate for temperature effects, dynamically adjusting calibration parameters based on measured temperature conditions rather than using fixed calibration values
2Measurement precision
If traditional calibration methods are used for pressure sensors, then measurement accuracy can be achieved, but calibration costs increase due to additional components and equipment
Solution Approach 1:
The piezo resistive elements serve dual functions: measuring pressure changes and measuring temperature-dependent resistance for calibration, while integrated temperature sensors provide temperature data for both compensation and calibration processes, eliminating the need for separate calibration components
Solution Approach 2:
The pressure sensor uses its own internal components (temperature sensors, piezo resistive elements, and processing circuitry) to perform self-calibration, eliminating dependency on external calibration equipment and reducing overall system complexity
3Adaptability or versatility
If pressure sensors are exposed to harsh environments, then they can operate in diverse conditions, but temperature dependencies cause calibration drift and measurement inaccuracies
Solution Approach 1:
The system measures resistance values at multiple temperature points and calculates temperature coefficients to dynamically compensate for temperature effects on pressure measurements, maintaining accuracy across varying environmental conditions
Solution Approach 2:
The system continuously monitors temperature using integrated temperature sensors and uses this feedback to adjust calibration parameters and compensate for temperature-dependent drift in real-time, ensuring accurate measurements in harsh environments
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 method reduces calibration time and costs while improving accuracy by directly measuring temperature effects on resistance, allowing for precise pressure measurements.
Implementation Method 1
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
Implementation Method 2
a built-in heating element integrated with the pressure circuitry adapted to heat the piezo resistive element based on a received heating signal
Implementation Method 3
the temperature circuitry is adapted to measure a temperature of the piezo resistive element and to output a temperature signal indicative of the temperature of the piezo resistive element
Data Source
AI summary
A method carried out by a processor for compensating temperature dependencies of a piezo resistive element integrated in a pressure sensor includes the steps of: receiving, from the temperature circuitry, a first temperature signal for determining a first temperature of the pressure circuitry; receiving, from the sensor die, a first output signal for determining a first resistive value of the piezo resistive element at the first temperature; 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; receiving, from the sensor die after termination of the heating, a second output signal for determining a second resistive value of the piezo resistive element at the second temperature; and storing, in the memory, an updated TC for the piezo resistive element calculated based on the first temperature, the first resistive value, the second temperature, and the second resistive value.