With the growing popularity and use of devices under the great umbrella that is the Internet of Things (IoT), the need for devices that are smaller, faster, cheaper and require less power is at an all time high with no intentions of slowing down. This is why many current research efforts are very focused on energy harvesting. Energy harvesting is the process of storing energy from external and ambient sources and delivering a small amount of power to low power IoT devices such as wireless sensors or wearable electronics. A charge pumps is a circuit used to convert a power supply to a higher or lower voltage depending on the specific application. Charge pumps are generally seen in memory design as a verity of power supplies are required for the newer memory technologies. Charge pumps can be also be designed for low voltage operation and can convert a smaller energy harvesting voltage level output to one that may be needed for the IoT device to operate. In this work, an integrated FinFET (Field Effect Transistor) charge pump for low power energy harvesting applications is proposed. The design and analysis of this system was conducted using Cadence Virtuoso Schematic L-Editing, Analog Design Environment and Spectre Circuit Simulator tools using the 7nm FinFETs from the ASAP7 7nm PDK. The research conducted here takes advantage of some inherent characteristics that are present in FinFET technologies, including low body effects, and faster switching speeds, lower threshold voltage and lower power consumption. The lower threshold voltage of the FinFET is key to get great performance at lower supply voltages. The charge pump in this work is designed to pump a 150mV power supply, generated from an energy harvester, to a regulated 650mV, while supplying 1uA of load current, with a 20mV voltage ripple in steady state (SS) operation. At these conditions, the systems power consumption is 4.85uW and is 31.76% efficient. Under no loading conditions, the charge pump reaches SS operation in 50us, giving it the fastest rise time of the compared state of the art efforts mentioned in this work. The minimum power supply voltage for the system to function is 93mV where it gives a regulated output voltage of $25mV. FinFET technology continues to be a very popular design choice and even though it has been in production since Intel's Ivy-Bridge processor in 2012, it seems that very few efforts have been made to use the advantages of FinFETs for charge pump design. This work shows though simulation that FinFET charge pumps can match the performance of charge pumps implemented in other technologies and should be considered for low power designs such as energy harvesting.

This book enables readers to gain a deep understanding of the challenges related to the design of a charge pump (CP). Analysis, modeling, design strategies and topologies are treated in detail. Novel and high-performance CP topologies and related design are organized in a coherent manner, with particular care devoted to ultra-low power and energy harvesting applications. The authors provide basic theoretical foundations as needed, in order to set the stage for readers’ comprehension of analyses and results. Exhaustive methodologies are presented and analytical derivations are included, enabling readers to gain insight on the main dependencies among the relevant circuit parameters. Although the material is presented in a formal and theoretical manner, emphasis is on the design perspective, using many practical examples and measured results.

Charge pumps are widely used in thermoelectric scavenging systems to increase the thermoelectric generator output voltage to a suitable voltage that can supply the standard integrated circuit. Threshold voltage cancellation (Vt cancellation) scheme is applied to cancel the threshold drop associated with each diode-connected device and improve charge pump performance. Applying this scheme by using the next stage higher voltage is presented. Improving the output stage using this scheme is also presented. Simulations are performed using TSMC 0.25 m CMOS technology in Spectre(r)

High-efficiency power delivery, as well as low-power circuit design continues to be an important concern in energy harvesting circuits and application that are limited by the battery capacity. This thesis presents a high-efficiency switched-capacitance charge pump in 20 nm III-V heterojunction tunnel field-effect transistor (HTFET) technology for low-input-voltage applications. It provides for higher efficiency than the conventional CMOS solution. The proposed circuit doubles the ratio of input voltage to output voltage, which is strongly related to its high efficiency. The state of art CMOS-based conventional switched-capacitance charge pump achieve power efficiency as 82% and output as 1.8V with 1.0V input voltage with 130nm technology. The steep-slope and low-threshold HTFET device characteristics are utilized to extend the input voltage range to below 0.20 V. Meanwhile, the uni-directional current conduction is utilized to reduce the reverse energy loss and to simplify the non-overlapping phase controlling. Furthermore, with uni-directional current conduction, an improved cross-coupled charge pump topology is proposed for higher voltage output and power-conversion-efficiency (PCE). Simulation results show that the proposed HTFET charge pump achieves 90.4% and 91.4% power conversion efficiency with a 1.0 k[omega] resistive load. The DC results obtained are 0.37 V and 0.57 V, when the input voltage is 0.20 V and 0.30 V, respectively.

The book discusses the materials, devices, and methodologies that can be used for energy harvesting including advanced materials, devices, and systems. It describes synthesis and fabrication details of energy storage materials. It explains use of high-energy density thin films for future power systems, flexible and biodegradable energy storage devices, fuel cells and supercapacitors, nanogenerators for self-powered systems, and innovative energy harvesting methodologies. Features: Covers all relevant topics in energy harvesting research and focuses on the current state-of-the-art techniques and materials for this application. Showcases the true potential of the nature in energy harvesting industry by discussing various harvesting mechanisms based on renewable and sustainable energy sources. Explains the recent trends in flexible and wearable energy storage devices that are currently being used in IoT-based smart devices. Overviews of the state-of-the-art research performed on design and development of energy harvesting devices. Highlights the interdisciplinary research efforts needed in energy harvesting and storage devices to transform conceptual ideas to working prototypes. This book is aimed at graduate students and researchers in emerging materials, energy engineering, including harvesting and storage.

The increasing demand in electronic portability imposes low power consumption as a key metric to analog and digital circuit design. Tunnel FET (TFET) devices have been explored mostly in digital circuits, showing promising results for ultra-low power and energy efficient circuit applications. The TFET presents a low inverse sub-threshold slope (SS) that allows a low leakage energy consumption, desirable in many digital circuits, especially memories.In this book, the TFET is explored as an alternative technology also for ultra-low power and voltage conversion and management circuits, suitable for weak energy harvesting (EH) sources. The TFET distinct electrical characteristics under reverse bias conditions require changes in conventional circuit topologies. In this book, ultra-low input power conversion circuits based on TFETs are designed and analyzed, evaluating their performance as rectifiers, charge pumps and power management circuits (PMC) for RF and DC EH sources.