MISIMO: A Multi-Input Single-Inductor Multi-Output Energy Harvesting Platform in 28-nm FDSOI for Powering Net-Zero-Energy Systems

Abstract

This paper presents a power management unit that meets the need of small-form-factor net-zero energy systems by aggregating the maximum available power from three different energy sources while simultaneously regulating three output power rails over a wide dynamic load range, while also managing the charging and discharging of a battery, all in a single-stage single-inductor converter. The proposed architecture uses hysteresis control to regulate the voltage of each harvester at their respective maximum power points (MPPs) using pulse-frequency modulation (PFM) and adaptive inductor ON-time, all via a low-power event-driven controller. The converter, fabricated in 28-nm fully-depleted silicon-on-insulator (FDSOI), achieves a peak efficiency of 89% and supports an output power range from $1~\mu \text{W}$ to 60 mW with efficiency >75% at $V_{\text {out}}=1$ V and >69% at $V_{\text {out}}=0.6-0.9$ V, all with a quiescent power of only 262 nW.