Bandyopadhyay Saurav, Mercier Patrick P, Lysaght Andrew C, Stankovic Konstantina M, Chandrakasan Anantha P
Massachusetts Institute of Technology, Cambridge MA, USA.
University of California, San Diego, La Jolla, CA, USA.
IEEE J Solid-State Circuits. 2014 Dec;49(12):2812-2824. doi: 10.1109/JSSC.2014.2350260.
This paper presents a nW power management unit (PMU) for an autonomous wireless sensor that sustains itself by harvesting energy from the endocochlear potential (EP), the 70-100 mV electrochemical bio-potential inside the mammalian ear. Due to the anatomical constraints inside the inner ear, the total extractable power from the EP is limited to 1.1-6.25 nW. A nW boost converter is used to increase the input voltage (30-55 mV) to a higher voltage (0.8 to 1.1 V) usable by CMOS circuits in the sensor. A pW Charge Pump circuit is used to minimize the leakage in the boost converter. Further, ultra-low-power control circuits consisting of digital implementations of input impedance adjustment circuits and Zero Current Switching circuits along with Timer and Reference circuits keep the quiescent power of the PMU down to 544 pW. The designed boost converter achieves a peak power conversion efficiency of 56%. The PMU can sustain itself and a duty-cyled ultra-low power load while extracting power from the EP of a live guinea pig. The PMU circuits have been implemented on a 0.18µm CMOS process.
本文介绍了一种用于自主无线传感器的纳瓦级电源管理单元（PMU），该传感器通过从内耳蜗电位（EP）（哺乳动物耳内70 - 100 mV的电化学生物电位）获取能量来实现自我供电。由于内耳的解剖学限制，从EP中可提取的总功率限制在1.1 - 6.25纳瓦。一个纳瓦级升压转换器用于将输入电压（30 - 55 mV）提升至传感器中CMOS电路可用的更高电压（0.8至1.1 V）。一个皮瓦级电荷泵电路用于使升压转换器中的泄漏最小化。此外，由输入阻抗调整电路和零电流开关电路的数字实现以及定时器和参考电路组成的超低功耗控制电路，可将PMU的静态功耗降至544皮瓦。所设计的升压转换器实现了56%的峰值功率转换效率。该PMU在从活豚鼠的EP提取功率时，能够维持自身运行并为一个占空比工作的超低功耗负载供电。PMU电路已采用0.18μm CMOS工艺实现。
