A low-noise readout circuit design for multi-bit quanta image sensor. (July 2022)

• Record Type: Journal Article
• Authors: Wang, Xiuyu; Li, Changchun; Zha, Wanbin; Nie, Kaiming; Xu, Jiangtao
• Is Part Of: Microelectronics journal. Volume 125(2022)
• Publication Date: 2022-07
• Subjects: Photon counting -- Quanta image sensor -- Low-noise charge transfer amplifier -- Digital correlated double sampling -- Signal-to-noise ratio; Microelectronics -- Periodicals; Microélectronique -- Périodiques; Microelectronics; Electronic journals; Journals - contents and abstracts; Periodicals; 621.3805
• DOI: 10.1016/j.mejo.2022.105463
• Languages: English
• ISSNs: 0959-8324

Abstract

Abstract: This paper presents a novel readout circuit based on low-noise charge transfer amplifier (LCTA) to suppress the readout noise in multi-bit quanta image sensor. A switched capacitor circuit is used in LCTA to reduce the kT/C noise introduced by its load capacitor, and make the noise from ADC further suppressed due to the increase of its output swing. The digital correlated double sampling of single-slope ADC is used to eliminate the fixed noise in LCTA. The low noise readout circuit is implemented by a 110 nm CMOS process. The simulation results show that the random noise of LCTA is reduced by 19% at a gain of 2 V/V compared to the conventional differential charge transfer amplifier. The increased output swing reduces the random noise power of ADC by 61%. In addition, the LCTA equivalent input fixed noise with 29.8 μVrms is eliminated. The proposed low-noise readout circuit improves the signal-to-noise ratio by 4.37 dB at small-signal conditions.