Song Yihang, Li Songfan, Zhang Chong, Li Shengyu, Lu Li
School of Computer Science and Engineering, University of Electronic Science and Technology of China, Qingshuihe Campus, Chengdu 611731, China.
Sensors (Basel). 2022 Apr 16;22(8):3074. doi: 10.3390/s22083074.
The last decade has seen significant advances in power optimization for IoT sensors. The conventional wisdom considers that if we reduce the power consumption of each component (e.g., processor, radio) into μW-level of power, the IoT sensors could achieve overall ultra-low power consumption. However, we show that this conventional wisdom is overturned, as bus communication can take significant power for exchanging data between each component. In this paper, we analyze the power efficiency of bus communication and ask whether it is possible to reduce the power consumption for bus communication. We observe that existing bus architectures in mainstream IoT devices can be classified into either push-pull or open-drain architecture. push-pull only adapts to unidirectional communication, whereas open-drain inherently fits for bidirectional communication which benefits simplifying bus topology and reducing hardware costs. However, open-drain consumes more power than push-pull due to the high leakage current consumption while communicating on the bus. We present , a novel approach introducing low power to the open-drain based buses by reducing the leakage current created on the bus. We instantiate on I2C bus and evaluate it with commercial off-the-shelf (COTS) sensors. The results show a 76.9% improvement in power efficiency in I2C communication.
在过去十年中，物联网传感器的功耗优化取得了重大进展。传统观念认为，如果我们将每个组件（例如处理器、无线电）的功耗降低到微瓦级别，物联网传感器就能实现整体超低功耗。然而，我们发现这种传统观念被颠覆了，因为总线通信在各组件之间交换数据时会消耗大量电能。在本文中，我们分析了总线通信的功率效率，并探讨是否有可能降低总线通信的功耗。我们观察到，主流物联网设备中的现有总线架构可分为推拉式或开漏式架构。推拉式仅适用于单向通信，而开漏式天生适合双向通信，这有利于简化总线拓扑并降低硬件成本。然而，由于在总线上通信时漏电流消耗较高，开漏式比推拉式消耗更多功率。我们提出了一种新颖的方法，通过减少总线上产生的漏电流，为基于开漏式的总线引入低功耗。我们在I2C总线上实现了该方法，并使用商用现货（COTS）传感器对其进行评估。结果表明，I2C通信的功率效率提高了76.9%。
