數位類比轉換器應用於雙波段聚焦平面紅外線偵測器之讀取電路研究與實現

Study and Implementation of Digital-to-Analog Converter for Readout Circuit of Dual-Band Infrared Focal Plane Array Detectors

呂藝全(Yi-Chuan Lu)

指導教授 ： 孫台平

國立暨南國際大學/科技學院/電機工程學系/碩士(2009年)

摘要

本論文將探討雙波段聚焦平面紅外線偵測器之讀出電路，利用數位類比轉換器控制雙波段感測器偏壓，完成陣列感測訊號之讀取。紅外線感測器以砷化鎵卅砷化鋁鎵所製作之量子井感測器。像素讀出電路採用直接注入為輸入級，以電流鏡方式達到閘極調變輸入的電路模式，且具有暗電流消除電路。將兩組輸入數位訊號至數位類比轉換器，完成感測器偏壓切換。
雙波段感測器之像素電路在50umx50um佈局面積，以SPICE模擬預設中波長之光電流範圍0-2nA每次增加0.25nA及長波長之光電流範圍0-10nA每次增加1nA，暗電流皆為100nA，預設長波長積分時間長度40us、中波長積分時間長度60us，訊號輸出範圍為中波長0.4V、長波長0.7V。完成雙波段感測陣列電路模擬。
數位類比轉換器電路是8位元電阻式加權型結構，電路模擬之動態結果97KHz輸入弦波得到SNDR為51dB，穩定時間為0.6us；靜態結果整體非線性誤差為0.43LSB、差異非線性誤差為0.32LSB，整體功率3.3mW。完成數位類比轉換器電路佈局與實作。

關鍵字

數位類比轉換器 ； 雙波段紅外線感測器 ； 讀出電路 ； 感測器偏壓 ； 光電流 ； 像素電路

並列摘要

This thesis will discuss readout circuit of dual-band infrared focal plane array detectors with a digital-to-analog converter to control readout signal and detector bias. The quantum well infrared sensor would be made of GaAs and GaAsAl. The structure of pixel readout circuit uses direct injection as input stage. The current mirror has been added to pixel circuit that formed gate-modulation-input circuit with in-pixel dark current cancellation. Two digital signals has inputted to digital-to-analog converter. Its functions are to select mid-wave or long-wave output signal and to change detector bias on focal plane array.
The dual-band has mid-wave and long-wave detector In-pixel on 50umx50um layout area. The output voltage range is 0.7v and 0.4v at the current interval 1nA and 0.25nA for long-wave and mid-wave at integration time 40us and 60us, respectively. Both the dark current is 100nA. The readout circuit of dual-band detector array has been simulated with digital-to-analog converter.
The 8-bit digital-to-analog converter accomplish uses R-2R ladder structure. The dynamic simulation of circuit has acquired SNDR 51dB when input sine-wave frequency 97kHz, settling time 0.6us, differential non-linearity error of 0.43LSB, integral non-linearity error of 0.32LSB, power dissipation of 3.3mW. Finally, the circuit has been layouted and implemented.

並列關鍵字

Digital-to-Analog Converter ； Dual-band infrared detector ； Readout Circuit ； Detector Bias ； Photocurrent ； Pixel-circuit

參考文獻

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