A Low Power ROIC with Extended Counting ADC Based on Circuit Noise Analysis for Sensor Arrays in IoT System. (3rd October 2022)

• Record Type: Journal Article
• Authors: Zhou, Ye; Lu, Wengao; Yu, Shanzhe; Yu, Dunshan; Zhang, Yacong; Chen, Zhongjian
• Other Names: Bhattacharya Sweta Academic Editor.
• Is Part Of: Journal of sensors. Volume 2022(2022)
• Publication Date: 2022-10-03
• Subjects: Detectors -- Periodicals; 681.205
• DOI: 10.1155/2022/5304613
• Languages: English
• ISSNs: 1687-725X

Abstract

Abstract : As the Internet of Things (IoT) is rapidly integrated into our daily life, the demand for high performance readout integrated circuit (ROIC) design for sensor arrays is boosting. This paper presents a low power, low noise ROIC with 14-bit column-parallel extended counting (EC) ADCs for sensor arrays targeting the IoT applications. The proposed EC-ADC adopts a pseudodifferential architecture to cancel even-order nonlinearity. The analog front-end is a G m stage, which employs a current-reuse topology to boost the transconductance and reduce noise without increasing current consumption. The upper 9-bit conversion is implemented during integration, and the residual voltage is converted by a 5-bit single-slope (SS) ADC, where the comparator is reused. A ping-pong integrator is proposed to reduce the reset time and improve linearity, eliminating the power-hungry CTIA structure. The ROIC is designed in 0.18 μ m 1P5M CMOS process for a 640 × 480 sensor array. Power consumption of the ROIC is 33 mW, and each column ADC consumes 40.1 μ W. Simulation results show an input-referred noise of 0.89 LSB (1.74 μ Vrms ), an integral nonlinearity of +0.92/-0.70 LSB, an ENOB of 12.87 bits, and a FoM of 131.1 fJ/step.