Efficient Energy Delivery for Low Power IoT Devices

Khondker Zakir Ahmed, Georgia Institute of Technology

11:00-12:00 Friday, 4 March 2016, ITE325b

Low power IoT Devices are growing in numbers and by 2020 there will be more than 25 Billion of those in areas such as wearables, smart homes, remote surveillance, transportation and industrial systems, including many others. Many IoT electronics either will operate from stand-alone energy supply (e.g., battery) or be self-powered by harvesting from ambient energy sources or have both options. Harvesting sustainable energy from ambient environment plays significant role in extending the operation lifetime of these devices and hence, lower the maintenance cost of the system, which in turn help make them integral to simpler systems. Both for battery-powered and harvesting capable systems, efficient power delivery unit remains an essential component for maximizing energy efficiency.

In this talk, I will discuss some of the most pressing challenges of energy delivery for low power electronics considering both energy harvesting as well as battery-powered conditions. Design techniques for very high conversion ratio, bias current reduction with autonomous bias gating, battery-less cold start, component and power stage multiplexing for reconfigurable and multi-domain regulators will be discussed. I will also present a highly integrated autonomous imaging system featuring a dual-purpose CMOS image sensor that is capable of both imaging and harvesting. This talk will focus only on the energy harvesting and power delivery aspect of this imaging system; presenting ‘a single inductor, single input, four output’power delivery unit with maximum power point tracking and prioritized output voltages. I will also present some silicon results from prototype chips developed in 130nm CMOS.

I will conclude the talk by discussing my vision of research on how low power analog electronics will play significant roles in realizing tomorrow’s ultra-low power, yet highly complex and smart electronic systems.

Khondker Zakir Ahmed is a PhD candidate in the School of Electrical and Computer Engineering at Georgia Institute of Technology, Atlanta, GA, where he works with the supervision of Professor Saibal Mukhopadhyay. He has received his MS in ECE from Georgia Tech in 2015 and BSc in EEE from Bangladesh University of Engineering and Technology in 2004. His primary research focus is power delivery circuit and systems design, specifically focused on low power electronics. His research accomplishments include innovative bias current reduction mechanism (Best in Session award, SRC TECHCON 2014), On-chip controller design for TEG/TEC for joint energy harvesting and hot-spot cooling (Best paper award, ISLPED 2014) and high conversion ratio hybrid down-converting regulator (Best in Session award, SRC TECHCON 2015). Khondker enjoys teaching; he has been a guest lecturer in several courses at Georgia Tech, and was a lecturer in the Department of Electrical and Electronic Engineering at East West University in Dhaka, Bangladesh for over a year before coming to Georgia Tech. Earlier, Khondker has worked as Analog IC Designer from 2005 to 2010 developing commercial power management ICs. He was a graduate intern at Intel Labs in the summers of 2013 and 2014, where he worked on adaptive voltage regulation for guardband reduction and cross-coupled voltage regulators with dynamic load sharing for microprocessors.