變頻式阻抗感測陣列讀取電路設計與實現

本論文提出變頻式阻抗感測陣列讀取電路架構，使用韋恩橋式振盪器(Wien-Bridge oscillator)作為可調式振盪電路的基礎架構，產生不同頻率之正弦波，來量測人體的不同部位，而在讀取電路部份，則採用共源極電路來作為像素電路，可偵測的阻抗範圍為20kΩ~100kΩ。至於顯像系統的部份，係利用以類比數位轉換器(Analog to Digital Converter，ADC)為主體架構的訊號介面板(proxy board)，來作為晶片與現場可程式化閘陣列(Field Programmable Gate Array，FPGA)開發板之間的傳遞橋樑，最後透過FPGA開發板將阻抗大小以灰階(Gray Level)影像的方式成像於顯示器上。該讀取電路透過國家晶片研究中心，採用TSMC 0.35μm 2P4M 5V製程進行設計、模擬與實做，單一像素布局面積為40μm×30μm，整體為4×4陣列讀出電路，功率消耗為16.372mW，輸出擺幅為2.7V。在顯像系統部份，訊號介面板的解析度為12-bit，最高操作速度為1.47MHz，將類比轉換為數位的時間為681ns，但由於FPGA開發板的視訊圖形陣列(Video Graphics Array，VGA)輸出只有10-bit，所以整體解析度被限制在10-bit。本論文設計可調頻率之優點，以配合所要量測之生物組織電性，並利用顯像系統來協助判斷與分析來自非侵入式阻抗感測器所接收到的資料。

關鍵字

變頻；陣列讀取電路；阻抗讀取；顯像系統；晶片

並列摘要

This paper presents impedance-sensing array readout circuit architecture with variable frequency technology, by using Wien-Bridge oscillator as the infrastructure of adjustable oscillator circuit which resulted in forming sine waves with different frequency to measure different parts of the body impedance. In readout circuit, the pixel structure is a common source circuit which detected impedance range from 20kΩ to 100kΩ. As for the design of the imaging system, the Analog to Digital Converter (ADC) is the main architecture of proxy board, which was used as the connection between the chip and Field Programmable Gate Array (FPGA) development board, and finally demonstrate measured impedance level in the Gray scale video image on the display through the FPGA development board. This readout circuit is designed, simulated, and implemented by using TSMC 0.35μm 2P4M 5V process from National Chip Implementation Center (CIC), the layout area of a single pixel is 40μm×30μm, overall for the 4×4 array readout circuit, the power consumption is 16.372mW, and output swing is 2.7V. In the imaging system, proxy board resolution is 12-bit, the maximum operating speed of 1.47MHz, ADC conversion rate is 681ns. However, with the DAC inside FPGA development board is limited to 10-bit, the full system resolution is restricted to 10-bit. In this thesis, the advantage of adjustable frequency to match the electrical properties of biological tissues measurement in analyzing and determining data received from non-invasive impedance sensor.

並列關鍵字

Variable Frequency ； Readout Circuit Array ； Impedance Reading ； Visualization System ； Chip

參考文獻

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Google Scholar

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