Common-Mode Amplifier Circuit for Drift-Stable Pressure Sensing
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Solution Overview
Problem
Traditional electronic pressure sensors face challenges in accurately measuring pressure over time due to ionic drift, especially at high temperatures, which affects the reliability of the signals generated.
Innovation Solution
The proposed electronic circuit uses a Wheatstone bridge configuration with boron-doped silicon piezo resistors and alternating power supplies to prevent ionic drift, coupled with differential and common mode amplifiers to amplify and filter signals, allowing for precise pressure and temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electronic pressure sensors are used, then pressure measurement is achieved, but ionic drift occurs especially at high temperatures reducing measurement reliability
Solution Approach 1:
The patent changes the material parameter from traditional semiconductor materials to boron-doped silicon piezo resistors, which have different electrical properties that resist ionic drift. This material substitution fundamentally alters the electrical characteristics to eliminate the harmful ionic drift effect while maintaining pressure sensing capability
Solution Approach 2:
The patent uses composite material structure by combining boron-doped silicon with piezo resistor technology, creating a material with enhanced properties that simultaneously provide pressure sensitivity and resistance to ionic drift, especially at high temperatures
2Reliability
If Wheatstone bridge configuration with boron-doped silicon piezo resistors is used, then ionic drift is reduced, but device complexity increases
Solution Approach 1:
The patent divides the measurement function into separate components: a Wheatstone bridge for differential measurement, a common mode amplifier for drift detection, and a differential amplifier for signal processing. This segmentation allows each component to be optimized independently while maintaining overall system reliability
Solution Approach 2:
The patent introduces a common mode amplifier as an intermediary component that specifically detects and handles the common mode signal containing ionic drift information, separating it from the differential pressure signal. This intermediary structure manages complexity by dedicating specific circuits to specific functions
3Measurement precision
If differential and common mode amplifiers are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent designs the amplifier circuit to perform multiple functions: the common mode amplifier handles both drift detection and temperature compensation, while the differential amplifier processes the pressure signal. This multi-functionality reduces the need for separate dedicated circuits for each function
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 solution effectively reduces ionic drift and enhances the sensitivity and dynamic range of pressure measurements, enabling accurate and reliable pressure sensing with minimal temperature interference.
Implementation Method 1
a Wheatstone bridge configuration with boron-doped silicon piezo resistors
Implementation Method 2
alternating power supplies to prevent ionic drift
Implementation Method 3
differential and common mode amplifiers to amplify and filter signals
Implementation Method 4
differential and common mode amplifiers to amplify and filter signals
Data Source
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AI summary
An analog discrete current mode negative feedback amplifier circuit for use with a micro-fused strain gauge is disclosed. The amplifier circuit includes a Wheatstone bridge coupled to a first power supply and a second power supply. The first power supply and the second power supply can be configured such that the periodically alternate between two voltage levels. The Wheatstone bridge can be coupled to a negative feedback amplifier circuit with common mode detection. The amplifier circuit can comprise a differential amplifier with a negative feedback configuration coupled to a common mode amplifier. In addition, the output of each of the amplifiers can be coupled to a common-mode amplifier. In a pressure sensing application, the output of the common mode amplifier serves to output the temperature while the differential amplifiers serve to output the pressure.