IEEE Power Electronics Magazine - June 2020 - 71

Li, Mobashar Yazdani, and Chee Chung. It begins by providing an overview of a 48-V dc-dc power architecture and
hybrid converter basics, including the evolution of hybrid
converters in data centers. This is followed by a discussion
on TLVR operating principles and transient response, and
physical implementation. In summary, this paper shows
that a two-stage 48-V dc-dc power solution ecosystem is
being established and hybrid converters are emerging as
attractive solutions for the 48-V one-stage fixed-ratio or
regulated intermediate bus conversion. An advantage of
TLVR technology is that it clears the long-standing theoretical bandwidth barrier. More innovation is needed for this
application, as noted by the Google engineers.
Another paper on 48-V server platform architecture is
written by engineers from Intel Corp. In this paper, "48-V
Server Platform Architecture and Design Challenges,"
Intel designers Horthense Tamdem, Meng Wang, Behzad
Vafakhah, Yinghua Ye, and Fan Zhengguo show that it
requires multiple sources for a cost-efficient ecosystem and
an industry standard for 48-V layout guidelines, as well as
efficiency above 98% for regulated 48-V to 12-V converter
solutions. Another paper of interest is on digital power in
the data center by Renesas. It emphasizes the fact that digital VR technology is playing a key role in the move to 48-V
data centers.
Other industry sessions of interest are on vehicle electrification (IS16), silicon and WBG switch performance
(IS04), energy harvesting enabling the IoT and 5G (IS11),
GaN applications and integration (IS19), and addressing
EMI challenges with WBG devices (IS24). In the session on
production use cases of WBG semiconductors (IS08), there
are three papers.
1) "Cost Effective ToF Lidar Using GaN Devices," by
John Glaser and Alex Lidow of EPC, indicates that
time of flight (ToF) lidar are finding use in autonomous vehicles because of their precise measurement
capabilities and that GaN can deliver performance to
meet the requirements for this ToF lidar application.
Citing examples of Waymo's self-driving cars and
Audi's Advanced Driver Assistance Systems, the EPC
authors suggest that lidar is the best choice for all
autonomous vehicles.
2) "High-Density 65 W USB-PD GaN Chargers: Market
Demand, Technical Solutions and Pricing," by Steve
Oliver of Navitas Semiconductor identifies numerous
65-W and above ac-dc adapters and chargers in the
smartphones and laptops that are powered by its GaN
power ICs. This presentation highlights the progress
GaN technology has made in the consumer power
supply market.
3) "Leading the GaN Revolution," by Philip Zuk of Transphorm and Sean Luangrath of Inergy demonstrates portable power using examples of a 3-kW electric generator
and a 6-kW residential solar system, both based on GaN
devices. Inergy is calling its off-grid whole-home solar
system-in-a-box Home Base.

Overall, the program offered four workshops on topics
ranging from magnetics to transportation electrification,
12 professional education seminars, six plenary talks, 30
industry sessions, 19 technical dialog sessions, and 40 technical sessions.
In the technical sessions program, there were many sessions devoted to renewable energy, WBG devices, components and magnetics, and cutting-edge power converters.
The growing popularity of EVs has stimulated many sessions addressing the challenges of building power trains,
driving motors, and fast charging batteries.
In the renewable arena, session T03 offered several
papers on renewable energy applications and highlighted
the move to 200-mm wafers for GaN-on-silicon HEMTs,
and papers T12.4 and session T08 addressed the challenges
of building PV inverters and microinverters. Advances in
battery integration, management, and protection were presented in session T27 with a focus on energy storage systems. Revealing a number of trends, the WBG space was
covered in numerous sessions: T12 on "GaN/Si Devices
and Components," T20 on "SiC Devices and Components,"
and T40 on "Wide Bandgap DC-DC Converter and Circuit
Modeling." For instance, paper T12.1 highlighted the move
to 200-mm wafers for the manufacturing of GaN-on-silicon
HEMTs. Papers T12.4 and T12.5 identified emerging applications benefiting from GaN devices.
Furthermore, the design, modeling, and applications
of wireless power transfer were the focus of session T15,
and sessions T16 and T32 divulged advances in transportation power electronics. Other technical sessions of interest included sessions on novel ac-dc and dc-dc conversion
architectures, covered in T23, T24, and T33.
Despite the current adversities, APEC organizers and
vendors did a great job in bringing a virtual version of APEC
2020 to its power electronics audience. Alas, nothing can
replace in-person meetings. We hope that coronavirus will
be defeated and that a live in-person APEC 2021 will happen next March in Phoenix, Arizona. See you, and stay safe
and well.

About the Author
Ashok Bindra (bindra1@verizon.net) received his M.S.
degree from the Department of Electrical and Computer
Engineering, Clarkson College of Technology (now Clarkson University), Potsdam, New York, and his M.Sc. degree
in physics from the University of Bombay, India. He is the
editor-in-chief of IEEE Power Electronics Magazine and a
Member of the IEEE. He is a veteran freelance writer and
editor with more than 35 years of editorial experience covering power electronics, analog/radio-frequency technologies, and semiconductors. He has worked for leading electronics trade publications in the United States, including
Electronics, EE Times, Electronic Design, Power Electronics Technology, and RF Design.

June 2020

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IEEE Power Electronics Magazine - June 2020

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