• Title/Summary/Keyword: LFSR counter

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A Design of Single Pixel Photon Counter for Digital X-ray Image Sensor (X-ray 이미지 센서용 싱글 픽셀 포톤 카운터 설계)

  • Baek, Seung-Myun;Kim, Tae-Ho;Kang, Hyung-Geun;Jeon, Sung-Chae;Jin, Seung-Oh;Huh, Young;Ha, Pan-Bong;Park, Mu-Hun;Kim, Young-Hee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.2
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    • pp.322-329
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    • 2007
  • A single pixel photon counting type image sensor which is applicable for medical diagnosis with digitally obtained image and industrial purpose has been designed with $0.18{\mu}m$ triple-well CMOS process. The designed single pixel for readout chip is able to be operated by single supply voltage to simplify digital X-ray image sensor module and a preamplifier which is consist of folded cascode CMOS operational amplifier has been designed to enlarge signal voltage(${\Delta}Vs$), the output voltage of preamplifier. And an externally tunable threshold voltage generator circuit which generates threshold voltage in the readout chip has been newly proposed against the conventional external threshold voltage supply. In addition, A dark current compensation circuit for reducing dark current noise from photo diode is proposed and 15bit LFSR(Linear Feedback Shift Resister) Counter which is able to have high counting frequency and small layout area is designed.

Analysis of Leakage Current of a Laser Diode by Equivalent Circuit Model (등가회로 모델에 의한 레이저다이오드의 누설전류 해석)

  • Choi, Young-Kyu;Kim, Ki-Rae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.2
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    • pp.330-336
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    • 2007
  • A single pixel photon counting type image sensor which is applicable for medical diagnosis with digitally obtained image and industrial purpose has tern designed with $0.18{\mu}m$ triple-well CMOS process. The designed single pixel for readout chip is able to be operated by single supply voltage to simplify digital X-ray image sensor module and a preamplifier which is consist of folded cascode CMOS operational amplifier has been designed to enlarge signal voltage(${\Delta}Vs$), the output voltage of preamplifier. And an externally tunable threshold voltage generator circuit which generates threshold voltage in the readout chip has been newly proposed against the conventional external threshold voltage supply. In addition, A dark current compensation circuit for reducing dark current noise from photo diode is proposed and 15bit LFSR(Linear Feedback Shift Resister) Counter which is able to have high counting frequency and small layout area is designed.

A Design of Digital CMOS X-ray Image Sensor with $32{\times}32$ Pixel Array Using Photon Counting Type (포톤 계수 방식의 $32{\times}32$ 픽셀 어레이를 갖는 디지털 CMOS X-ray 이미지 센서 설계)

  • Sung, Kwan-Young;Kim, Tae-Ho;Hwang, Yoon-Geum;Jeon, Sung-Chae;Jin, Seung-Oh;Huh, Young;Ha, Pan-Bong;Park, Mu-Hun;Kim, Young-Hee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.7
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    • pp.1235-1242
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    • 2008
  • In this paper, x-ray image sensor of photon counting type having a $32{\times}32$ pixel array is designed with $0.18{\mu}m$ triple-well CMOS process. Each pixel of the designed image sensor has an area of loot $100{\times}100\;{\mu}m2$ and is composed of about 400 transistors. It has an open pad of an area of $50{\times}50{\mu}m2$ of CSA(charge Sensitive Amplifier) with x-ray detector through a bump bonding. To reduce layout size, self-biased folded cascode CMOS OP amp is used instead of folded cascode OP amp with voltage bias circuit at each single-pixel CSA, and 15-bit LFSR(Linear Feedback Shift Register) counter clock generator is proposed to remove short pulse which occurs from the clock before and after it enters the counting mode. And it is designed that sensor data can be read out of the sensor column by column using a column address decoder to reduce the maximum current of the CMOS x-ray image sensor in the readout mode.