Semiconductor Pressure Sensor Circuit Reducing ADC Resolution Requirements
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Solution Overview
Problem
Existing pressure instrumentation devices face increased circuit scale and power consumption due to the need for high-resolution voltage measuring circuits when measuring large changes in resistance values, making them inefficient for precise pressure measurements.
Innovation Solution
A semiconductor device with a variable current generating unit, potential difference determining unit, and control unit that controls direct current flow to eliminate potential differences between measurement nodes in a bridge circuit, allowing for accurate resistance value calculations using general-purpose DA converters and comparators, thereby reducing circuit complexity and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-resolution voltage measuring circuit (16-bit or 24-bit AD converter) is used to measure large potential differences, then measurement precision is improved, but device complexity and circuit scale increase
Solution Approach 1:
The patent changes the measurement parameter from voltage to current. Instead of measuring voltage directly with high-resolution ADCs, the invention uses a transimpedance amplifier to convert the current signal (from the bridge circuit) into a voltage signal that can be measured with lower-resolution ADCs, thereby reducing circuit complexity while maintaining measurement precision
Solution Approach 2:
The patent introduces a transimpedance amplifier as an intermediary device between the bridge circuit and the ADC. This amplifier converts the current output from the bridge circuit into a voltage signal, allowing the use of standard-resolution ADCs instead of requiring high-resolution voltage measuring circuits, thus reducing circuit scale while preserving measurement accuracy
2Device complexity
If the amplification factor of the amplifier circuit is reduced to suppress output voltage, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent replaces the voltage amplification mechanism with a current-to-voltage conversion mechanism using a transimpedance amplifier. This substitution eliminates the need for high-gloss voltage amplifiers while maintaining signal integrity, thereby reducing device complexity without sacrificing measurement precision
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 enables precise pressure measurements without the need for high-resolution voltage measuring circuits, suppressing circuit scale and power consumption while maintaining measurement accuracy, and can be applied to various pressure measurement systems.
Implementation Method 1
a pressure-sensitive resistance element whose resistance value changes according to pressure change
Data Source
AI summary
A semiconductor device includes a variable current generating unit that sends a direct current of a value according to a control signal from one measurement node of a bridge circuit in which a change amount of a resistance value of a pressure-sensitive resistance element appears as a potential difference between measurement nodes, a potential difference determining unit that determines whether or not the potential difference has been generated, and a control unit that outputs the control signal to the variable current generating unit so that the variable current generating unit sends the direct current of a value that does not generate the potential difference based on a determination result of the potential difference determining unit.