Dual-Mode Pressure Sensor with Adaptive Bridge Circuits
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Solution Overview
Problem
Conventional pressure sensors have limited measuring ranges and sensitivity, making them inadequate for applications involving higher pressure variations, such as in-ear headphones and diving computers, where they often require multiple sensors to cover different pressure ranges.
Innovation Solution
A pressure sensor with a micromechanical sensor element featuring a pressure-sensitive diaphragm and electrodes that operate in two modes: a first mode for ambient pressures and a second mode for higher pressures, utilizing different electrical interconnections to form measuring capacitors, allowing for expanded measuring ranges without modifying the sensor element, and switching between modes based on detected pressures or predefinable intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is optimized for high sensitivity in a specific pressure range, then smaller pressure changes can be detected, but the sensor cannot accurately measure pressures outside its optimized range
Solution Approach 1:
The patent implements dynamic switching between two operating modes with different electrical interconnections. The first operating mode uses a first bridge circuit configuration optimized for ambient pressure range with high sensitivity, while the second operating mode uses a second bridge circuit configuration optimized for higher pressure range. A switching mechanism dynamically selects the appropriate operating mode based on the current pressure conditions, allowing the sensor to maintain optimal sensitivity across a wide overall pressure range.
2Adaptability or versatility
If multiple pressure sensors are used to cover different pressure ranges, then all pressure ranges can be measured, but the device complexity and cost increase
Solution Approach 1:
The patent makes a single pressure sensor element multi-functional by implementing two different bridge circuit interconnections within the same device. The first bridge circuit connects the pressure-sensitive capacitor in a configuration optimized for ambient pressure measurement, while the second bridge circuit reconfigures the same capacitor for higher pressure measurement. This allows one sensor to perform the function of multiple sensors would otherwise be needed, reducing device complexity and cost while maintaining the ability to measure across different pressure ranges.
3Adaptability or versatility
If the electrical interconnection of sensor components is changed to expand measuring range, then different pressure ranges can be measured, but manufacturing complexity increases
Solution Approach 1:
The patent segments the electrical interconnection into two distinct bridge circuit configurations that can be independently implemented. The first bridge circuit and second bridge circuit are designed as separate interconnection schemes that can be manufactured using different fabrication processes or layers. This segmentation allows each bridge circuit to be optimized for its specific pressure range without compromising the other, and enables flexible manufacturing choices such as implementing one bridge circuit in the base material and the other in an ASIC layer.
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
Enables efficient operation in various pressure ranges with enhanced accuracy and reduced susceptibility to noise and temperature changes, maintaining sensitivity and cost-effectiveness by using the same micromechanical sensor element with adaptive operating modes.
Implementation Method 1
the diaphragm electrode, together with the at least one first reference electrode, forms a second measuring capacitor for detecting a second measuring pressure
Data Source
AI summary
A pressure sensor includes a micromechanical sensor element including a pressure-sensitive diaphragm, which spans a cavity in a base material and includes a diaphragm electrode. A fixed counter electrode is situated inside the cavity and, with the diaphragm electrode, forms a first measuring capacitor for detecting a first measuring pressure. A reference capacitor is situated inside the cavity and includes a first and a second fixed reference electrode. The pressure sensor is operable in a first operating mode, in which the first measuring capacitor and the first reference capacitor are interconnected in a first bridge circuit. The pressure sensor is operable in a second operating mode, in which the diaphragm electrode, the counter electrode and the reference electrodes are interconnected in such a way that the diaphragm electrode, together with the at least one first reference electrode, forms a second measuring capacitor for detecting a second measuring pressure.