應用於血糖感測系統之電流至頻率轉換器

Linear Current to Frequency Converter Applied for Glucose Sensing System

阮新日光(NGUYEN-TAN-NHUT QUANG)

指導教授 ： 鍾文耀

中原大學/工學院/電子工程研究所/碩士(2011年)

https://doi.org/10.6840/cycu201100660

摘要

本論文主要的目標是設計一個線性電流至頻率轉換器，應用在安培電位式血糖量測系統之上。本系統分為兩個部分，分別是前端類比部分和後端數位部分。
在整個線性電流至頻率轉換器中，前端主要是用傳統電荷平衡的震盪器為主要架構，將輸入電阻替換成電流控制電阻，這樣一個線性化的技術，可以做一個線性化處理，使得輸出頻率線性化。另外，設計了一個三種增益切換電路，可以調整輸入範圍和輸入動態範圍，讓系統可以適用於目標應用。使用nanosim進行佈局後模擬，分別顯示三個增益的輸入動態範圍在一般情況下為400nA到3.5uA、2uA到16uA和4uA到32uA；線性度為99%，功率消耗為926.48uW。最後使用TSMC0.35um製程將整個系統進行下線。
整個血糖量測系統後端數位部分，使用微控制器MPC82G516A程式化一個計數器，完成類比轉數位轉換器。最後，將轉換完的數據顯示在兩行的液晶顯示器上。

關鍵字

電流至頻率轉換器

並列摘要

This research mainly aims to design a linear Current to Frequency converter (CFC) which is applied for glucose sensing system where amperometric electrochemical sensors are used. To complete the whole system, two parts, analog front-end and digital back-end, were designed.
Analog front-end is linear CFC where the conventional charge balance oscillator was adopted to build main structure. One modify was done is that the input resistor was replaced by the current controlled resistor (CCR) where a linearize technique was used to linearize the output frequency. Furthermore, conditioning circuit was also designed to acquire three sets of input range and extend the origin of input dynamic range of the linear CFC to make it appropriate for target application. Post-simulation results by using nanosim show three sets of input dynamic range 400 nA to 3.5 µA, 2 µA to 16 µA, and 4 µA to 32 µA with linearity of 99.0% and power consumption of 926.48 µW for typical case. The linear CFC was taped out by using TSMC 0.35 µm technology.
Digital back-end is MCU, MPC82G516A which was programmed to work as a counter to complete the A/D converter for the glucose sensing system. Finally, the conversion data was displayed on a two-line LCD.

並列關鍵字

A/D Converter ； Linear Current to Frequency Converter ； Current Controlled Converter

參考文獻

[2.] Diamond, D., Principles of chemical and biological sensors. 1998: Wiley-Interscience.

[3.] Eggins, B.R., Chemical sensors and biosensors. 2002: Wiley.

[4.] Chung, W.Y., et al. A Wide Current Range Readout Circuit with Potentiostat for Amperometric Chemical Sensors. 2009: Springer.

[9.] Tadic, N. and D. Gobovic, A voltage-controlled resistor in CMOS technology using bisection of the voltage range. Instrumentation and Measurement, IEEE Transactions on, 2002. 50(6): p. 1704-1710.

[10.] Wang, C.C., et al., Voltage-to-frequency converter with high sensitivity using all-MOS voltage window comparator. Microelectronics Journal, 2007. 38(2): p. 197-202.