| Summary: | 碩士 === 中原大學 === 電子工程研究所 === 95 === Bergveld invented ISFET in 1970. A solid device of ISFET which combines chemical membrane and metal-oxide-semicondictor sences selected ion-chroma in solution. Various manufactures, readout circuits and calibrations were presented in backward-looking thirty years, but ISFET’s undesirable effect which is including light, noise, temperature, drift, hysteresis, flow rate, body effect and life cycle is limited justness in measure machine.
All in one chip is the currect trend in VLSI circuit design. But this concept isn’t suitable for all systems. This thesis presented the dual chip design. One combines improving floating-gate readout circuit and Bandgap reference circuit which is maked in a replaceable stick, and the other combines 16-bit SAR-ADC, 16-bit digital calibration circuit and display driver which is converted ISFET information to display panel and accomplish the portable pH-meter system.
This thesis presents the portable pH-meter system which is designed by signal 3V CR-2032 battery and using TSMC 0.35um Mixed Signal 2P4M Polycide 3.3 technical manufacture to accomplish all designs and layouts. The new circuit architecture by the thesis presented can be reduced ISFET’s undesirable effect and drop error. The entire system’s battery life is over 1000 hours by continuing using, and two chip’s power consumption is approximative 2.85uW. This portable pH-meter system is accureted 0.001 pH, and can be measured pH value from 2 to 12. The functions of calibration circuit are incluing signal point, dual points and three points by calibration.
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