Abstract
Many applications use the electronic nose (Enose) system, such as environmental monitoring, food processing, pollution measurement and medical diagnosis. The ability to monitor and identify various chemical gases is also valuable. Although the sensing capabilities of our noses are well beyond that achievable by any existing instrument, many applications require non-human odor detecting ability. Compared with a traditional gas chromatograph-mass spectrometer (GC-MS), electronic nose systems have the advantage of being smaller, more portable, and cost economic. The research focuses on an integrated conducting polymer gas sensor array and its adaptive interface circuit compatible with standard CMOS processes for an electronic nose chip. The sensors use polymer-carbon black composites, which swell reversibly and create resistance change upon exposure to chemical vapors. The initial resistances of sensors are influenced by temperature or humidity. Therefore, an adaptive interface circuit is proposed to cancel the baseline signal drift. With the progress of MEMS process, there are many researches about miniature conducting polymer gas sensors. But most of the researches could not compatible with standard CMOS processes. We proposed the conducting polymer gas sensor array that compatible with standard CMOS processes. It is very important for the portable electronic nose system. Using standard CMOS process to integrate sensors and circuits can achieve small size, low-power, low noise and low cost.