Large area X-ray CMOS digital pixel sensor based on pulse width modulation for high frame rate applications

Author

Kang, Dong-Hyung ; Lee, Daewoo ; Kim, Myung Su ; Kim, Chong-Kwon ; Cho, Moonju ; Yoo, Hyoungsuk ; Kim, Youngjae ; Kim, Heonhwan ; Kim, Jung-Ho ; Park, Ki-Hong ; Lee, E.J. ; Lim, K.T. ; Cho, Guangsup

Author_Institution

Korea Adv. Inst. of Sci. & Technol., Daejeon, South Korea

fYear

2013

fDate

Oct. 27 2013-Nov. 2 2013

Firstpage

1

Lastpage

4

Abstract

In wafer-scale CMOS image sensors, the 3-transistor structure suffers from its low speed. To overcome this limitation, we propose a digital pixel sensor which has a digital-pixel output instead of analog-pixel output as in a conventional 3-transistor pixel. The digital pixel sensor can provide a high frame because it eliminates analog-to-digital conversion time. In addition, it removes the noise from long analog-signal paths. As a prototype, we designed a 4.5mm × 4.0mm chip having 24 × 16 pixels of 100μm × 100μm using standard 0.18μm CMOS technology. With 2MHz clock, the readout time for each pixel was 6micro seconds. When 3000pixels are in each column of a full-wafer-size CMOS image sensor, 50fps can be achieved with the digital pixels based on pulse width modulation.

Keywords

CMOS image sensors; X-ray imaging; analogue-digital conversion; wafer-scale integration; 3-transistor structure; X-ray CMOS digital pixel sensor; analog-signal paths; analog-to-digital conversion time; high frame rate applications; pulse width modulation; size 0.18 mum; size 100 mum; size 4.0 mm; size 4.5 mm; wafer scale CMOS image sensor; CMOS image sensors; CMOS integrated circuits; CMOS technology; Clocks; Photoconductivity; Photodiodes; Pulse width modulation;

fLanguage

English

Publisher

ieee

Conference_Titel

Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2013 IEEE

Conference_Location

Seoul

Print_ISBN

978-1-4799-0533-1

Type

conf

DOI

10.1109/NSSMIC.2013.6829608

Filename

6829608