3V可攜式離子感測場效電晶體感測器訊號處理之特殊應用積體電路系統研究

3V ISFET Based Hand-held pH-meter Signal Processor Design Using ASIC Design Methodology

王耀鋒(Yaw-Feng Wang)

指導教授 ： 鍾文耀

中原大學/工學院/電子工程研究所/碩士(2002年)

https://doi.org/10.6840/cycu200200143

摘要

本篇論文於整個酸鹼感測器系統實現方面，為了達到可攜式、低電壓和製作成本較低廉的理念，本論文主要採用並驗證三伏特電壓架構之低電壓酸鹼度感測計積體電路系統，並實現了基本時脈模組、具微處理機介面之12位元雙斜率類比/數位轉換器、酸鹼感測計系統單晶片的整合與測試和具嵌入式微處理器晶片的實現，以利未來各個類比與數位電路單元整合之系統單晶片(System On a Chip, SOC)的實現和其它量測系統的開發。

本論文利用離子敏感型場效電晶體(Ion-Sensitive Field Effect Transistor，ISFET)進行酸鹼度感測，我們採用恆壓恆流法進行此類感測器的訊號讀出；主要原理為定電流及定電壓之工作條件下，感測器操作將呈線性的變化。而由前端之類比檢測電路取出訊號，經由雙斜率類比/數位轉換器電路予以轉為數位訊號，再經由數位訊號處理模組進行二點校正並將資料計算編碼後傳送至LED或3 1/2數字型LCD顯示器上顯示pH值。

本篇論文所有積體電路晶片實現均委託國家晶片系統設計中心(CIC)以UMC 0.5μm DPDM的製程技術製作完成。

關鍵字

酸鹼檢測器 ； 離子敏感型場效電晶體 ； 石英振盪電路 ； 微處理器 ； 類比/數位轉換器 ； 混模積體電路

並列摘要

In past two decades, micro-sensors based on CMOS IC technology have caught more attention on the electronic industries, universities and research organizations. The major concerns on the application needs, operation region, reliable and flexible circuit configurations are most important issues in order to collect the accurate, stable and reliable data from ISFET sensor. To develop an efficient signal processor is the most important task for hand-held pH meter design and realization.

The objective of this research is to present a design and implementation of a mixed-mode ASIC for ISFET-based biosensor signal processing applications including H+ sensing and hand-held pH meter. For battery power consideration, the proposed signal processing ASIC consists of low voltage (3V) analog front-end readout circuits and digital processing modules have been developed and fabricated in a 0.5mm double-poly double-metal CMOS technology. Both of custom layout and automatic placement and routing methodology are adopted in the design. The core die size is around 3400 x 3300 mm2 and is packaged in 68 pins CLCC socket. The corresponding sensitivities of Al2O3 type commercial ISFET(SENTRON 2001) is 54.4mv/pH. The measurement accuracy of the chip is about 0.2pH between pH2 to pH12.

Furthermore, the digital processing modules of the proposed ASIC are designed using pure logic and state machine. In order to replace the digital modules of the proposed chip and to catch up with the trend of System-On-a-Chip design methodology, an embedded 8-bits micro- processor called Forth P8 is also taken in this thesis. The developed Forth P8 chip has been fabricated in a 0.5mm double-poly double-metal CMOS technology by using self-developed cell library and automatic placement and routing methodology. The core die size is around 4000 x 4200 mm2. It has been proved to function work by using IMS test station. Finally, to pack all analog modules and P8 microprocessor into a SOC will be our next technical challenge.

並列關鍵字

pH meter ； System-On-a-Chip ； Forth ； Application Specific Integrated Circuit (ASIC) ； CMOS ； Ion-Sensitive Field Effect Transistor (ISFET)

參考文獻

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