The proliferation of Internet-of-Things (IoT) systems and human body sensors is rapidly transforming the way we interact with our surroundings. As these devices increase in number and longevity, there grows a critical need to find sustainable and convenient power sources. Shrinking consumer electronics have generated a demand for battery-less power sources forsome applications. Significant interest in studying energy harvesting techniques exists as a solution to power these devices. In particular for interactive electronics meant to exist on and around the human body, kinetic energy of human movement is a popular energy scavenging source.
This dissertation presents an electrostatic, charge-pumping energy harvesting system capable of scavenging energy from capacitive changes induced by the human body. As is well known for touchscreen devices, the proximity of a finger alters the effective value of small capacitances. These capacitance changes drive a current which is rectified to charge an energy storage component. This technology is fabricated in a standard CMOS process, and is also compatible with other mediums such as printed circuit boards, conductive fabrics, and paper. These systems transduce the kinetic energy of a human finger tap to electrical energy in the range of pico- to nano- joules, depending on the size, material, and design of the capacitive touch-sensing electrodes. We highlight the harvester’s ability to power low-power applications such as light-emitting diodes and ring oscillators. This system illustrates one solution for powering the growing number of electronic devices with on-demand, user-generated interactive human movement.