Precise Measurement of Gas Volumes by Means of Low-Offset MEMS Flow Sensors with μL/min Resolution

Abstract

Experiments devoted to evaluate the performance of a MEMS thermal flow sensor in measuring gas volumes are described. The sensor is a single-chip platform, including several sensing structures and a low-offset, low-noise readout interface. A recently proposed offset compensation approach is implemented obtaining low temperature drift and excellent long time stability. The sensor is fabricated by applying a simple micromachining procedure to a chip produced using the BCD6s process of STMicroelectronics. Application of a gas conveyor allowed inclusion of the sensing structure into a channel of sub-millimeter cross-section. The results of measurements performed by making controlled air volumes pass through the sensor channel in both directions at rates from 0.1 to 5 mL/min are described.

Design of Signal Generators Using Active Elements Developed in I3T25 CMOS Technology Single IC Package for Illuminance to Frequency Conversion

“…The area of simple electronics sensing read-outs focuses on the sensing of physical quantities [34], such as temperature [35], mechanical pressure [36], acoustic pressure [37], electromagnetic field [38], humidity [39], gas [40], bio-signal [41], or capacity [42,43], etc. However, the detection and measurement of light and illuminance [44] received quite limited attention in recent works.…”

CMOS Current Feedback Operational Amplifier-Based Relaxation Generator for Capacity to Voltage Sensor Interface

“…They are required for transformation of various physical quantities to measurable information in the form of an electrical signal (voltage, current). Such physical quantities, for instance, can be temperature [2], mechanical pressure [3], acoustic pressure [4,5], electromagnetic field [6,7], humidity [8], gas [9,10] and biosignals [11,12]. Due to different operating conditions in the low-voltage (LV) design (e.g., supply voltage and requirement for the power consumption), specific methods and principles of the readout systems must be used.…”