Abstract
Based on an analysis of the signal characteristics of gas sensors, this work presents a chemoresistive sensor readout circuit design for detecting gases with slow response time characteristics. The proposed readout circuit directly generates a reference voltage corresponding to the initial value of the gas sensor and extracts only the amount of gas concentration change in the sensor. Because the proposed readout circuit can adaptively regenerate the suitable reference voltage under various changing ambient conditions, it can alleviate the variation in output values at the same gas concentration caused by non-uniformities among gas sensors. Furthermore, this readout circuit effectively eliminates the initial value shifts due to the poor reproducibility of the gas sensor itself without requiring complex digital signal calibrations. This work focuses on a commercially viable readout circuit structure that can effectively obtain slow response gas information without requiring a large capacitor. The proposed readout circuit operation was verified by simulations using spectre in cadence simulation software. It was then implemented on a printed circuit board with discrete components to confirm the effectiveness with existing gas sensor systems and its commercial viability.
Highlights
With the development of electronic devices, the demand for microsensor applications has been increased for improving the quality of human life
Because there is a limitation for improving gas sensor performance only through the physical structure and material modifications, the studies on gas sensing readout integrated circuits (ROICs) should be performed together with the sensor characteristics to effectively overcome the limits of gas sensor performances in this field
To verify compatibility and operation in terms of commercialization, in this work, the proposed readout structure was implemented on a printed circuit board (PCB) board using general-purpose discrete elements of differential amplifier, analog-to-digital converter (ADC), and digital-to-analog converter (DAC), to verify its effectiveness in various commercial gas-sensing systems
Summary
With the development of electronic devices, the demand for microsensor applications has been increased for improving the quality of human life. Metal-oxide-semiconductor (MOS)-based gas sensors are attracting attention with the development of semiconductor manufacturing technology owing to their compatibility with Internet of Things (IoT) applications These sensors have chemoresistive characteristics and provide a simple interface circuitry for the signal conversion. The chemoresistive characteristics of gas sensors change in accordance with the surrounding conditions in the environment, such as temperature, humidity, and pressure [10] This leads to different initial values of the gas sensor (i.e., offset variations) for each set of sensing measurements, causing non-uniformity of signal conversion results even with the same gas concentration.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
