A 32nA Fully Autonomous Multi-Input Single-Inductor Multi-Output Energy-Harvesting and Power-Management Platform with 1.2×10<sup>5</sup> Dynamic Range, Integrated MPPT, and Multi-Modal Cold Start-Up
Shuo Li, Xinjian Liu, Benton H. Calhoun
Abstract
Energy harvesting and power management units (EHPMUs) are gaining popularity for self-powered Internet-of-Things (loT) applications due to their ability of extracting ambient energy and powering load circuits through a single block. Among all EHPMU architectures, the multi-input single-inductor multi-output (MISIMO) [1]–[6] has the benefits of small form factor, high efficiency, extracting energy from multi-modal energy sources, and powering different types of loads. Self-powered loT applications also require the EHPMUs to have ultra-low quiescent power, wide dynamic range, and autonomous features to support their deployment without any battery. However, previous EHPMUs either consume too much power [1]–[3] or only provide a small dynamic range [4], [5]. They also suffer from two-stage power delivery causing cascaded power loss [1], [5] and lack of essential components such as voltage references [6] for a fully deployable solution. To overcome all these challenges, in this work, we propose a fully autonomous MISIMO EHPMU platform that can extract energy from three energy harvesters with both AC and DC modalities and provide four custom voltage rails together with on-chip maximum power-point tracking (MPPT) and multi-modal cold start-up circuits. This EHPMU achieves 32nA quiescent current, 1.2x1 0 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> dynamic range, 3.2x energy-extraction gain for piezoelectric energy harvesting, and 80% efficiency when delivering <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1\mu \mathrm{A}$</tex> output current.