- 學位論文
應用於離子感測系統之 增量型三角積分類比至數位轉換器
Incremental Delta-Sigma Analog to Digital Converter Applying in Ion Sensitive System
摘要
本研究之目的在於提供應用於離子感測系統中感測器讀出電路 與後端微控器之間的介面電路，此系統應用於水質監控，以提供工作效率及生活品質，如氫離子、鈉離子、氯離子等，皆適用於此感測系統。 整體系統包含前端類比區塊與後端數位區塊，前端類比區塊包括 切換電容式積分器、比較器、一位元數位至類比轉換器所構成一階三角積分調變器；而後端數位區塊使用計數器，前後結合為一增量型三角積分類比至數位轉換器，相較於其他常見之三角積分轉換器，架構較為簡單。與其他不同在於此為應用於電子舌系統（多離子感測系統）之資料轉換器，適用輸入訊號為低頻（直流）之情形。 本研究適用於輸入訊號擺幅為1.15V～2.15V(全擺幅＝1V)，訊號頻率低於6Hz（直流訊號）之離子感測系統，此轉換器為13 位元之解析度，在應用於氫離子感測器，可將精確度至小數點後兩位，其線性特性DNL 達-0.0015LSB 與INL 約在-0.37LSB～0.15LSB 之間皆達應用之範圍，適合於離子感測系統。 全系統採用提供之國家晶片中心 TSMC 0.35 μm Mixed-Signal 2P4M Polycide 3.3V/5V 與馬來西亞微電子所MIMOS 0.35μm 2P3M 3.3V 製程下線製作，此系統採用兩種製程下線，係可驗証電路之驅動之能力。
並列摘要
The purpose of this research is to design an analog-to-digital (A/D) converter that would interface the sensor readout circuit and microcontroller unit of the ion-sensitive meter system. This system is used to measure different kinds of ions such as hydrogen ions, sodium ions, chloride ion, etc. Moreover, this system can be extended to electronic tongue system (multi-ion sensing system) that can be applied to water quality monitoring system to improve our quality of life. The A/D converter used the first-order incremental delta-sigma structure for simplicity. This consists of two parts: the front-end analog blocks and back-end digital blocks. The analog block consists of switch capacitor integrator, comparator, and one bit digital to analog converters. While, the digital block consists of a simple counter. The design A/D converter has a resolution of 13 bits having an input range of 1.15V - 2.15V, which corresponds to a full scale ratio of 1V, and an input frequency bandwidth of 6Hz, which is acceptable since the input is limited only to DC signals. The linearity performance of the converter is -0.0015LSB for Differential Non-Linearity Error (DNL) and -0.37LSB ~ - 0.15LSB for Integral Non-Linearity Error (INL). The converter’s performance is enough to provide at least two decimal point accuracy for hydrogen ion sensing system. In order to completely verify the ability of the circuit to convert data, the designed A/D converter is implemented using two kinds of process on two different foundries: Taiwan’s TSMC 0.35um Mixed-Signal 2P4M Polycide 3.3V/5V process submitted through Taiwan National Chip Implementation Center (CIC) and Malaysian Institute of Microelectronics Systems (MIMOS) 0.35um 2P3M 3.3V process.