Ultra-low Power Circuit Design for Miniaturized IoT Platform

Abstract:

This dissertation examines the ultra-low power circuit techniques for cubic millimeter-scale Internet of Things (IoT) platforms. The cubic millimeter-scale IoT devices are known for their small form factors and limited battery capacity and lifespan. Therefore, ultra-low power consumption of always-on blocks is required for the cubic millimeter-scale IoT devices that adopt aggressive duty-cycling for high power efficiency and long lifespan. Several problems need to be addressed regarding IoT device designs, such as ultra-low power circuit design techniques for sleep mode and energy-efficient and fast data rate transmission for active mode communication. This dissertation highlights the ultra-low power always-on systems, focusing on energy efficient optical transmission in order to miniaturize the IoT systems. First, a battery-less sub-nW micro-controller for an always-operating system implemented with a newly proposed logic family is presented. Second, this dissertation proposes an always-operating sub-nW light-to-digital converter to measure instant light intensity and cumulative light exposure, which employs the characteristics of this proposed logic family. Third, an ultra-low standby power optical wake-up receiver with ambient light canceling using dual-mode operation is presented. Finally, an energy-efficient low power optical transmitter for an implantable IoT device is suggested.