A back-illuminated global-shutter CMOS image sensor with pixel-parallel 14b subthreshold ADC

• Main Authors: Sakakibara, Masaki, Ogawa, Koji, Sakai, Shin, Tochigi, Yasuhisa, Honda, Katsumi, Kikuchi, Hidekazu, Wada, Takuya, Kamikubo, Yasunobu, Miura, Tsukasa, Nakamizo, Masahiko, Jyo, Naoki, Hayashibara, Ryo, Furukawa, Yohei, Miyata, Shinya, Yamamoto, Satoshi, Ota, Yoshiyuki, Takahashi, Hirotsugu, Taura, Tadayuki, Oike, Yusuke, Tatani, Keiji, Nagano, Takashi, Ezaki, Takayuki, Hirayama, Teruo
• Format: Conference Proceeding
• Language: English
• Subjects: CMOS image sensors; Latches; Random access memory; Repeaters; Sensors; Timing; Writing
• ISSN: 2376-8606
• DOI: 10.1109/ISSCC.2018.8310193

Rolling-shutter CMOS image sensors (CISs) are widely used [1,2]. However, the distortion of moving subjects remains an unresolved problem, regardless of the speed at which these sensors are operated. It has been reported that by adopting in-pixel analog memory (MEM) in pixels, a global shutter (GS) can be achieved by saving all pixels simultaneously as stored charges [3,4]. However, as signals from a storage unit are read in a column-wise sequence, a light-shielding structure is required for the MEM to suppress the influence of parasitic light during the reading period. Pixel-parallel ADCs have been reported as methods of implementing GS on a circuit [5,6]. However, these techniques have not been successful in operations on megapixels because they do not address issues such as the timing constraint for reading and writing a digital signal to and from an ADC in a pixel owing to increase in the number of pixels and the increase in the total power consumption of massively parallel comparators (CMs).