A 0.5V 4.95µW 11.8fps PWM CMOS Imager with 82dB Dynamic Range and 0.055% Fixed-Pattern Noise

📋 论文概要

提出一种0.5V供电的PWM CMOS图像传感器，采用时间域转换克服低电压下信号摆幅限制，并补偿阈值变化效应。实现了4.95µW超低功耗、82dB动态范围和0.055%固定模式噪声，适用于植入式生物医学设备。

💡 主要创新点

• 利用脉冲宽度调制(PWM)将光信号转换为时间域，在0.5V超低电压下实现高信号摆幅。
• 通过电路技术补偿像素间阈值电压变化，将固定模式噪声降低至0.055%。
• 在极低功耗(4.95µW)下实现82dB动态范围，平衡了低电压与高动态范围之间的矛盾。

🏷 关键词

📄 原文摘要

Lately, developing a low-voltage, power-efficient image sensor for disposable or implantable biomedical devices has become an important topic [1,2]. Instead of using a conventional CMOS active pixel sensor (APS), converting a photo-generated signal into the time domain using pulse width modulation (PWM) has become a popular way to overcome the limited signal swing under low-voltage operation [2,3,4,5]. Our design offers solutions to the following problems: 1) threshold-variation effects in PWM-based sensors, and 2) the low dynamic range of circuits with low supply voltage. In this paper, a 0.5V 64×40-pixel PWM imager is prototyped in standard 0.18µm CMOS. A threshold-variation-cancelling (TVC) scheme is developed to solve the non-uniformity issue of in-pixel comparators, which results in 0.055% fixed-pattern noise (FPN). To deal with the limited signal swing at 0.5V operation, a programmable current-controlled threshold (PCCT) scheme is implemented to

👥 作者与机构

Meng-Ting Chung, Chih-Cheng Hsieh

National Tsing Hua University, Hsinchu, Taiwan