Tutorial 6


Single- and Multi-Cell Battery Charging and Management Systems for IoT and Automotive Applications

Ayman Fayed, Ohio State University


This tutorial will introduce the basic operation and characteristics of battery cells commonly used in IoT devices and automotive applications, including their charging/discharging profiles, self-discharging, internal impedance, charging cycles, and the effect of ambient and operating conditions on all these aspects. This will be followed by presenting the most common charging schemes used to charge single- and multi-cell battery stacks, including the constant current constant-voltage charging scheme and the pulse charging scheme and the specific safety hazards and consideration for Li-Ion batteries. The tutorial will then present the circuit implementation of linear and switching battery charger topologies, fuel gauging circuits, and cell-monitoring and cell-balancing techniques. The tutorial will be concluded by presenting various implementation and performance examples of commercial battery charging systems and a discussion of practical considerations.


Ayman Fayed received his M.Sc. and Ph.D. degrees in Electrical & Computer Engineering from The Ohio State University in 2000 and 2004 respectively. From 2000 to 2009, he held several technical positions in the area of analog and mixed-signal and power management IC design at Texas Instruments Inc., where he contributed to many product lines for wire-line, wireless, and multi-media devices. From 2000 to 2005, he was with the Connectivity Solutions Dept. at TI, where he worked on the analog frontend design of various high-speed wire-line transceivers, and on fully integrated switching/linear regulators and battery chargers for portable media players. From 2005 to 2009, he was a member of the technical staff with the wireless analog technology center at TI, where he worked on delta-sigma data converters for various wireless standards, and on the development of fully-integrated power management solutions for mixed-signal SoCs with multi-RF cores in nanometer CMOS. Dr. Fayed joined the Dept. of Electrical & Computer Engineering at Iowa State University in 2009, where he held the Northrop Grumman Assistant Professorship. He then joined the Dept. of Electrical & Computer Engineering at The Ohio State University in 2015 as an associate professor. He is the founder and director of the Power Management Research Lab (PMRL) and his current research interests include on-chip power grids for dynamic energy distribution in highly-integrated systems, high-frequency switching regulators with on-chip and on-package passives for SoCs, low-noise power supplies and power supply modulators for analog and RF circuits, energy-harvesting and battery charging platforms for power-restricted & remotely-deployed systems, and power conversion in emerging technologies. Dr. Fayed is a senior member of IEEE, an associate editor for IEEE TCAS-I and previously for TCAS-II, and serves in the technical program committee of RFIC, ISCAS, and the steering committee of MWSCAS. He is the author/co-author of many publications in the field and holds 8 US patents. Dr. Fayed is a recipient of NSF CAREER Award in 2013, and a co-recipient of the 2015 Darlington Best Transactions Paper Award from the IEEE Circuits and System Society.