A Single-Chip Image Sensor Node With Energy Harvesting From a CMOS Pixel Array

Jong Hwan Ko, Mohammad Faisal Amir, Khondker Zakir Ahmed, Taesik Na, Saibal Mukhopadhyay

Abstract: This paper presents a single-chip image sensor node with energy harvesting from the pixel array. The design includes a 128 × 96 pixel array that can be reconfigured to form an on-chip photovoltaic cell to harvest energy. An onchip power management unit harvests energy from the pixel array, and delivers multiple regulated output voltage domains to power the sensor, image processor, and memory. The image processor is a low-overhead moving object detection unit to reduce the volume of transmitted data. The proposed sensor node is implemented on a single die in 130-nm technology. The pixel array demonstrates the peak harvested power of 2.1μW. The power dissipation of sensor is reduced by utilizing low-power circuit techniques, including block-level pipelining, power gating, and low-voltage memory. The system can be self-powered to process a frame at every 7 s. We discuss design approaches for improving the self-power performance. The noise characteristic of the reconfigurable sensor is analyzed, and the need for noise-robust moving object detection is evaluated for better image quality and improved self-power performance.