Liu Xinjian, Truesdell Daniel S, Faruqe Omar, Parameswaran Lalitha, Rickley Michael, Kopanski Andrew, Cantley Lauren, Coon Austin, Bernasconi Matthew, Wang Tairan, Calhoun Benton H
IEEE Trans Biomed Circuits Syst. 2023 Dec;17(6):1185-1201. doi: 10.1109/TBCAS.2023.3309779. Epub 2024 Jan 10.
This article presents a fully autonomous system-on-chip (SoC) that can be distributed along a fiber strand, capable of simultaneously harvesting energy, cooperatively scaling performance, sharing power, and booting-up with other in-fiber SoCs for ultra-low-power (ULP) sensing applications. Utilizing a custom switched capacitor energy harvesting and power management unit (EHPMU), the SoC can efficiently redistribute and reuse harvested energy along the fiber. Integrated on-chip, the ULP RISC-V digital core and temperature sensor enable energy-efficient sensing and computation at nanowatt power levels. A dedicated ripple boot-up and cooperative dynamic voltage and frequency scaling (DVFS) further optimize the operation and physical size of the system. Fabricated in 65 nm, measurement results show that the proposed SoC achieves 33 nW power consumption for the whole chip under 92 Lux lighting condition and can reduce control power down to 2.7 nW for the EHPMU. With the proposed power sharing and cooperative DVFS techniques, the SoC reduces the illuminance needed to stay alive by >7× down to 12 Lux. Integrated into a mm-scale polymer fiber, our SoC demonstrates the feasibility of fully autonomous and ULP on-body sensing systems in resource-constrained fiber environments.
本文介绍了一种可沿光纤链分布的全自主片上系统（SoC），它能够同时收集能量、协同扩展性能、共享功率，并与其他光纤内SoC一起启动，用于超低功耗（ULP）传感应用。利用定制的开关电容能量收集和电源管理单元（EHPMU），该SoC可以沿光纤高效地重新分配和再利用收集到的能量。集成在芯片上的超低功耗RISC-V数字内核和温度传感器能够在纳瓦功率水平下实现高效传感和计算。专用的纹波启动以及协同动态电压和频率缩放（DVFS）进一步优化了系统的运行和物理尺寸。该芯片采用65纳米工艺制造，测量结果表明，所提出的SoC在92勒克斯光照条件下整个芯片的功耗为33纳瓦，并且可以将EHPMU的控制功耗降低至2.7纳瓦。通过所提出的功率共享和协同DVFS技术，该SoC将维持工作所需的照度降低了7倍以上，降至12勒克斯。集成到毫米级聚合物光纤中后，我们的SoC证明了在资源受限的光纤环境中实现全自主和超低功耗人体传感系统的可行性。
