Research On Readout Circuit System Based On Nano Materials Field Effect Transistor Sensors

Advanced sensing technology has penetrated into all fields of human life,and the circuit system of realizing transistor sensor to detect and read display data is of great significance to human life and major sensing fields.In recent years,commercial detectors that combine sensors and readout circuits are mostly electronic noses,p H meters,and biological protein meters.Their main features include: small design area(convenient handheld),high-precision sensitivity,low power consumption and cost etc.Unfortunately,first,the ideal experimental test environment does not realize the response of the sensor in the real environment.Second,due to the high cost and large size of laboratory instruments,the real-time performance of the real detection environment is limited.Third,the characteristics of sensors prepared by multiple processes/materials are different,resulting in complicated monitoring methods.In order to detect transistor sensors in real time in practical applications,the circuit readout system must solve the above problems.In this study,we propose a transistor sensing array circuit,which includes digital-toanalog/analog-to-digital conversion,signal acquisition,data processing,and interface display functions.The monitoring system uses the DAC to perform bias voltage/gate voltage regulation on the sensor,so that it works in different working regions to control the sensitivity of the sensor.The system is suitable for a variety of material transistor sensors,allowing the sensor resistance to vary from 10KΩ to 100MΩ,enabling 5 orders of magnitude wide dynamic range sensor testing.The system realizes the performance of automatic switch in the test,and can transform the gain coefficient to amplify the weak sensor signal and output the sensor output resistance by the fitting algorithm.We successfully tested a handheld monitoring system with a gas sensor at room temperature.Under the condition of 0.1V bias voltage and 0V gate voltage,the system realizes hydrogen detection of 200PPM-10000 PPM,calculates the change trend of the resistance of the sensing element in real time,and realizes carbon-based sensing from 480KΩ-9.8MΩ.realtime measurement changes.In addition,this study proposes a readout circuit system for transistor sensing arrays to realize infrared grayscale image reading of 64*64 pixels.The system includes 64-channel analog front end,analog-to-digital conversion,array switch,FPGA timing control,and MATLAB interface APP design.The system collects data from the sensor array in a "select in row & output in list" method,and decodes the photoelectric analog signal into a digital signal through a 14-bit precision ADC.The system uses serial port to USB to communicate with the PC,and the PC-interface APP reads the sensor array signal to displays it in picture format(JPG).This paper completes the design of the readout system from a single sensor to an array sensor,which implements both a fitting algorithm for specific sensing and a uniform fitting algorithm for large-scale sensing devices.The sensing circuit expands the potential application fields of the sensor,and will promote the development of handheld detectors with high sensitivity and low power consumption,which is of great significance to the practical development of transistor-type sensors.