近年來隨著生活飲食習慣不同，因惡性腫瘤而死亡之人數上升，其中女性好發癌症第一名為乳癌，為了可以有效提早發現乳癌並提早治療，乳癌篩檢是重要的工具，經臨床實驗證明，乳房X光攝影能夠提早發現乳癌，降低死亡機率，因此乳房X光攝影相對甚於重要。本論文研究目的為設計並實現X光感測器之讀出電路，設計之讀出電路前端使用之像素架構為國立清華大學范森雄博士所提出的新穎像素，像素的好處是很小的漏電流，此像素可應用於大面積之醫學影像且圖框更新率為2-frame/s。
本文讀出電路設計採用了數位相關二次取樣，用於減少FPN雜訊，低功耗，且可避免電容匹配與時脈饋入問題，且實現類比數位轉換。數位相關二次取樣電路包含放大器，比較器，數位類比轉換器，上下計數器和電壓位準移位器。讀出電路解析度需求為11bit。讀出電路使用TSMC 0.35μm 2P4M製程實現，晶片面積為3.385mm×1.412mm = 4.78 mm2。

Recently, owing to significantly change in eating habits, the number of deaths due to malignant tumors has increased. Among them, female are prone to breast cancer. In order to effectively detect breast cancer and treat it early, mammography is an important tool. It has been proven that mammography can detect breast cancer effectively and reduce the chance of death, therefore mammography is relatively important. The purpose of this thesis is to design and implement the readout circuit of X-ray sensor. This readout circuit is designed base on a novel pixel that was proposed by Dr. Fan Sen-Shyong in National Tsing Hua University. The advantage of the pixel is the small leakage current, and it can be applied to a large area of medical image. The frame rate is 2-frame per second in this read out circuit.
In this paper, the readout circuit design adopts digital correlated double sampling technique to reduce FPN noise, decrease power consumption, and avoid capacitive mismatching and clock skew problems. The digital correlated double sampling circuit includes an amplifier, a comparator, a digital to analog converter, an up/down counter, and a voltage level shifter. The resolution of the proposed readout circuit is 11 bits, and it was implemented using the TSMC 0.35μm 2P4M process. Its die area is 3.385mm × 1.412mm.

[1]衛生福利部國民健康署,民國104年女性乳房年齡別發生率及死亡率女性,2015. Available: https://www.hpa.gov.tw/Home/Index.aspx
[2] Sen-Shyong Fann, Yeu-Long Jiang and Huey-Liang Hwang, "Operating principles and performance of a novel a-Si:H p-i-n-based X-ray detector for medical image applications," in IEEE Transactions on Electron Devices, vol. 50, no. 2, pp. 341-346, Feb. 2003.
[3] S. Yoshihara et al., "A 1/1.8-inch 6.4 MPixel 60 frames/s CMOS Image Sensor With Seamless Mode Change," in IEEE Journal of Solid-State Circuits, vol. 41, no. 12, pp. 2998-3006, Dec. 2006.
[4] Hologic,Inc. ʺSelenia Dimensions With Acquisition Workstation8000ʺ Available: https://www.hologic.com/hologic-products/breast-skeletal/selenia-dimensions- mammography-system
[5]Siemens,Inc. ʺDigital Fullfield Mammography Diagnosisʺ Available: https://www.fda.gov.tw/MLMS/ShowFile.aspx?LicId=06022077&Seq=001&Type=9
[6]GE,Inc. ʺSenographe 2000Dʺ Available:http://www.cura.in/pdf/FFDM.pdf
[7] Y. Chen, Y. Xu, A. J. Mierop and A. J. P. Theuwissen, "Column-Parallel Digital Correlated Multiple Sampling for Low-Noise CMOS Image Sensors," in IEEE Sensors Journal, vol. 12, no. 4, pp. 793-799, April 2012.
[8] P. Ju, K. Suyama, P. Ferguson and W. Lee, "A highly linear switched-capacitor DAC for multi-bit sigma-delta D/A applications," Proceedings of ISCAS'95 - International Symposium on Circuits and Systems, Seattle, WA, USA, 1995, pp. 9-12 vol.1.
[9] Kim, Daehyeok et al. “A high speed CMOS image sensor with a novel digital correlated double sampling and a differential difference amplifier” Sensors (Basel, Switzerland) vol. 15,3 5081-95. 2 Mar. 2015.
[10] D. Lee and G. Han, "High-speed, low-power correlated double sampling counter for column-parallel CMOS imagers," in Electronics Letters, vol. 43, no. 24, pp. 1362-1364, 22 Nov. 2007.
[11] W. Singh and R. Sharma, "High resolution, high speed and low power comparator for high speed ADCs," 2015 International Conference on Soft Computing Techniques and Implementations (ICSCTI), Faridabad, 2015, pp. 113-116.
[12] M. F. Snoeij, A. J. P. Theuwissen, K. A. A. Makinwa and J. H. Huijsing, "A CMOS Imager With Column-Level ADC Using Dynamic Column Fixed-Pattern Noise Reduction," in IEEE Journal of Solid-State Circuits, vol. 41, no. 12, pp. 3007-3015, Dec. 2006.
[13] T. Sugiki et al., "A 60 mW 10 b CMOS image sensor with column-to-column FPN reduction," 2000 IEEE International Solid-State Circuits Conference. Digest of Technical Papers (Cat. No.00CH37056), San Francisco, CA, USA, 2000, pp. 108-109.
[14] T. Yamada, S. Kasuga, T. Murata and Y. Kato, "A 140dB-Dynamic-Range MOS Image Sensor with In-Pixel Multiple-Exposure Synthesis," 2008 IEEE International Solid-State Circuits Conference - Digest of Technical Papers, San Francisco, CA, 2008, pp. 50-594.
[15] 董皓裕, ʺ醫療用數位X光影像系統之讀出電路與區動電路設計, ʺ清華大學電子功成研究所學位論文,2012 : p 1-86.
[16] 蘇聖員, ʺX光感測讀出電路設計與數位相關二次取樣之實現, ʺ清華大學電子功成研究所學位論文,2016 : p 1-72.
[17] M.Korner,C.H. Weber,S.Wirth,K-J. Pfeifer, Advances in Digital Radiography: Physical Principles and System Overview.2007.p675-686.
[18] Behzad Razavi,”Design of analog Cmos integrated circuit”,McGraw-Hill,Boston,2001.
[19] B. C. Kim, J. Jeon and H. Shin, "Temporal Noise Analysis and Reduction Method in CMOS Image Sensor Readout Circuit," in IEEE Transactions on Electron Devices, vol. 56, no. 11, pp. 2489-2495, Nov. 2009.
[20] Y. Nitta et al., "High-Speed Digital Double Sampling with Analog CDS on Column Parallel ADC Architecture for Low-Noise Active Pixel Sensor," 2006 IEEE International Solid State Circuits Conference - Digest of Technical Papers, San Francisco, CA, 2006, pp. 2024-2031.
[21] S. Yewale and R. Gamad, "Design of Low Power and High Speed CMOS Comparator for A/D Converter Application," Wireless Engineering and Technology, Vol. 3 No. 2, 2012, p. 90-95.
[22] A. Van den Bosch et al., "A 12 bit 200 MHz low glitch CMOS D/A converter," Proceedings of the IEEE 1998 Custom Integrated Circuits Conference (Cat. No.98CH36143), Santa Clara, CA, USA, 1998, pp. 249-252.
[23] C. Liu, S. Chang, G. Huang and Y. Lin, "A 10-bit 50-MS/s SAR ADC With a Monotonic Capacitor Switching Procedure," in IEEE Journal of Solid-State Circuits, vol. 45, no. 4, pp. 731-740, April 2010.
[24] M. Bigas, E. Cabruja, J. Forest, J. Salvi ," Review of CMOS image sensors," Microelectronics Journal, Vol: 37,2006, Page: 433-451
[25] Koga, Fuminori, Yayori Kasagi, Shuichi Watanabe and Tetsuo Nomoto. “A Low Power Dual CDS for a Column-Parallel CMOS Image Sensor.” (2012).