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Multi-input Single-Inductor Multi-output EHPMU

Energy harvesting and power management units (EHPMUs) are gaining popularity for self-powered Internet-of-Things (IoT) 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 IoT 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, 1.2×105 dynamic range, 3.2× energy-extraction gain for piezoelectric energy harvesting, and 80% efficiency when delivering 1μA output current.