An ISFET automated output calibration system implementation on reconfigurable FPGA device with MATLAB artificial intelligence interfacing

摘要

ISFET area is a promising technology developed recently, with widespread application in ion based sensing applications such as PH measurement, TPS & water quality measurement & other ION sensitive chemical and biological measurements. To utilize ISFETs to form an integrated ph sensor is a promising avenue. To implement ISFET based ph sensors the need of calibration of V_thvarious / id variation of with per instance measurement of actual ph value is required. This waste introduces a unique concept of dynamic auto calibration of ISFET pH sensor, using reconfigurable FPGA hardware architecture in conjunction with artificial intelligence. The proposed work employs real time on the fly calibration system. Where in the output voltage of ISFET is sampled by ADC at various ph level & the same are digitized and sent to calibration pc/laptop, whereas in an artificial neural network learns the voltage output ph curve, & predicts the voltage values at various ph levels vs. Voltage output values & programs LUT (look up table) in FPGA flash. After calibration, the device captures ISFET Vout values from ADC and searches the lookup table, computes compensation value & feed DAC to compensate the voltage output of ph sensor as per tradition standards in real time.