A 1-V Wide Swing Image Sensor With Simultaneous Energy Harvesting and Imaging Modes for IoT Applications

Abstract

Image sensors with energy-harvesting capabilities aid in the development of self-powered Internet of Things (IoT) nodes. By achieving simultaneous energy harvesting and imaging, these image sensors make it possible to eliminate batteries and directly achieve self-powered operation. The article proposes a 1-V wide swing image sensor with simultaneous energy harvesting and imaging modes. The proposed pixel utilizes a vertical n+/p-well/DNW/P-sub structures as the photodiode based on a standard 180-nm CMOS mixed-signal process. The n+/p-well is used for imaging, while the p-well/DNW and DNW/P-sub are used for energy harvesting with p-well and P-sub shorted together. Moreover, a traditional 4T pixel has been improved by using CMOS pairs as the switches and zero-threshold NMOS as the source follower. The rail-to-rail pixel output swing can be achieved. An image sensor with simultaneous energy harvesting and imaging modes, which consists of a 32×32 pixel array, a controller, and a dual-channel PWM quantizer, has been designed and fabricated. Measurement results show that the average power consumption of the image sensor is approximately 899.6 nW with 25 fps at 3 klx. The proposed image sensor has a DR of 47.3 dB under a 1-V supply. The measured power generated by energy harvesting while maintaining imaging functionality is 194 pW/lx/mm2.

Zhipeng Li

PhD Student

My research interests include circuit design of image sensors and energy harvesting circuits.

Jingjing Liu

Associate Professor

My research interests include low-power smart micro-sensor integrated circuit design, image sensors, biomedical sensors, and energy harvesting circuits.

Yuchen Wang

Master’s Student

My research interests include the design of high dynamic range and multi-mode image sensors.

Wenji Mo

Master’s Student

My research interests include circuit design of low-power RISC-V processors and self-powered SoCs.

Feng Yan

PhD Student

My research interests include circuit design of analog front end for biomedical applications and sensor interfaces.

Jian Guan

PhD Student

My research interests include the design of solar cells and energy harvesting circuits.

Kangkang Sun

PhD Student

My research interests include circuit design of analog to digital converter for biomedical applications and SAR ADC.