UC San Diego

Today, internet of things (IoT) connect the world in way more than we ever thought possible, changing the way we live, work, and interact with each other. Power management has an important role in a successful IoT deployment. Building an efficient, low-cost, and compact power management unit (PMU) becomes a key for enabling remote, long-lived, and small wearable and IoT devices. Thus, this thesis presents miniaturized, efficient, and low cost power management solutions using innovation on both the architecture and circuit level.

The wireless sensor network (WSN) modules of next generation IoT and wearable devices will be implemented on a single system on a chip (SoC) platform that can ultimately combine digital, analog/mixed signal, and RF to provide the highest level of integration and conservation of area. Most of IoT SoC designs will be implemented in FDSOI technology which is available in small geometry processes to merge the benefits of ultra-low power as well as high performance. Accordingly, the proposed power management solutions for IoT and wearable devices in this thesis, fabricated in 28nm FDSOI to be integrated on the same die as the WSN modules.

Energy harvesting is an essential concept for the future of power management in IoT to enable autonomous operation that doesn’t require battery charging or replacement. Thus, the first part of the thesis 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. IoT and wearable devices are powered by efficient and durable Li-ion batteries with voltage range 2.8-4.2V. Thus, the second part presents a fully integrated Li-ion compatible hybrid DC-DC converter that meets the needs of small-form-factor IoT while offering superior performance compared to prior-art fully-integrated converters. The challenges of implementing a high-voltage tolerant DC-DC converter with high conversion ratio, using low voltage transistors and poor quality on-chip passives on 28nm FDSOI addressed. The third part presents a miniaturized Li-ion compatible hybrid single-inductor multi-output (H-SIMO) that independently regulates three different output power rails while combining the hybrid topology benefits for compact and efficient implementation. The last part focuses on finding the maximum number of levels and possible multilevel

configurations for a given number of capacitors.