ISFET感測器之補償機制與可攜式酸鹼度儀設計

The Design of Compensation Method and Portable pH Meter for ISFET Sensor

王敏嘉(Ming-Chia Wang)

指導教授 ： 鍾文耀

中原大學/工學院/電子工程研究所/碩士(2006年)

https://doi.org/10.6840/cycu200600164

摘要

摘 要
在本論文主要之目的為開發可攜式酸鹼度計系統之低功率前端感測訊號模組晶片，可搭配離子感測場效電晶體來量測溶液之氫離子濃度，並利用LabView程式驗證此前端感測訊號模組晶片與溫度補償機制，本論文中詳述了系統設計流程，驗證方式，電路工作原理，電路模擬結果與晶片量測數據。
本論文所設計之前端感測訊號模組晶片，可分為橋式讀出電路與溫度感測讀出電路，其中橋式讀出電路包含能帶隙參考電壓電路、類比減法器與軌對軌運算放大器，而溫度讀出電路部份由臨界電壓萃取器當作溫度感測器結合類比減法器與反相放大器組成，此晶片已使用TSMC 0.35μm Mixed Signal 2P4M Polycide 3.3V製程技術完成製作與量測，總功率消耗為1.8mW，酸鹼值適用範圍為pH2~pH12，最大誤差為0.423pH。

關鍵字

低功率前端感測訊號模組晶片 ； 溫度感測讀出電路 ； 橋式讀出電路 ； 臨界電壓萃取器 ； 可攜式酸鹼度計系統 ； 反相放大器 ； 能帶隙參考電壓電路 ； 軌對軌運算放大器

並列摘要

The ion sensitive field effect transistors (ISFETs) have been used increasingly in physiological data acquisition and environmental monitoring in recent years. The pH monitoring of river, waste water or urine becomes more important in daily life. In addition, a single chip implementation is a trend for battery-operated devices such as glucose monitors, heart beat detectors and pH-meters. The objective of this thesis is to present the design and implementation of a low-power dissipation analog front-end signal processing chip including bridge-type readout circuit and VT extractor circuit couple with a compensation electronics.
For battery power consideration, the proposed low power bridge-type readout circuit consists of a self-biased bandgap reference, an analoge subtractor and rail-to-rail operational amplifier; In addition, an PMOS-type VT extractor circuit couple with a temperature compensation electronics have been successfully fabricated in a 0.35慆 CMOS technology.
The proposed chip applied to Si3N4-gate ISFETs demonstrate a 1.8mW power comsumption for the buffer solutions with the pH value changed from 2 to 12. In addition, the LABVIEW software are used to compensate the ISFET thermal characteristics. Experimental results show that the temperature dependence of the Si3N4-gate ISFET sensor improved from 8mV/°C to less than 0.8mV/°C.

並列關鍵字

temperature compensation electronics ； ISFET ； bridge-type readout circuit ； PMOS-type VT extractor circuit ； low power

參考文獻

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