IEEE Power Electronics Magazine - June 2014 - 21

eturning to Fort Worth, Texas, with a larger program and attendance, including exhibitors, this
year's Applied Power Electronics Conference
(APEC), held 16-20 March, focused on the practical and applied aspects of the power electronics
business as promised. In addressing the issues relevant to
practicing engineers, APEC shed some new light on key
emerging trends via plenary talks, technical and industry sessions, rap discussions, and demonstrations in the exhibit hall.

Digital Object Identifier 10.1109/MPEL.2014.2312278
Date of publication: 20 June 2014

Speaking of emerging trends, Texas Instruments' power
management Chief Technology Officer Dave Freeman highlighted the evolution of power management from discretes
to system-level solutions to meet the stringent needs of cloud
technologies and automotive electronics. Following Freeman's plenary talk, Northrop Grumman's adiabatic pointof-load (APOL) Program Manager Don Tan, who is also the
president of the IEEE Power Electronics Society, provided a
system-level glimpse of power electronics. During his talk,
Tan stressed an interesting concept for point-of-load (POL)
regulators-the APOL. Offering efficiency greater than 98%,
Tan said that with a small improvement in efficiency, APOLs
can increase power throughput capability without increasing capacity. For instance, he added, throughput power can
be doubled with a small efficiency improvement of 1.9%.
Unlike traditional POL, APOL produces virtually no heat,
hence the name Adiabatic POL, noted Tan.
Tan's group, however, has built an APOL prototype using
commercially available pulsewidth-modulated (PWM) software and components. The results obtained for this 3.3Vdc, 10-W prototype are shown in Figure 1. It is observed
that an efficiency greater than 97.5% was reported for wide
variations in lines, loads, and temperatures. Peak efficiency
offered by the APOL is 99% at 3.3 Vdc . Tan said that his company's APOL was in production.

Higher Goals
In another plenary talk, the U.S. Department of Energy's
Advanced Research Projects Agency-Energy (ARPA-E) Program Director Tim Heidel underscored the agency's initiatives
to concurrently achieve high efficiency, high power density,
and high reliability at low cost in a single power supply
design, a common objective across all applications. Toward
this goal, ARPA-E has funded several projects under initiatives such as agile delivery of electric power technologies
(ADEPT) and strategies for wide-bandgap inexpensive transistors for controlling high-efficiency systems (SWITCHES).
One such ADEPT target was a high-density POL converter with ten times improvement in power density and
more than 88% efficiency using three-dimensional (3-D)
integrated technology. It was developed by Virginia Tech's
Center for Power Electronic Systems using International
Rectifier's low-voltage gallium nitride-on-silicon high-electron-mobility transistors (GaN-on-Si HEMTs). To tap the
high-frequency benefits of GaN transistors, passive components are also being driven simultaneously, including the
development of microfabricated magnetics and new circuit
topologies. As a result, the ADEPT project, which has been
under way for the last four years, has achieved new systemlevel goals for power supplies, as shown in Figure 2.
Similar results were also presented for high-voltage silicon
carbide (SiC) technology. The talk suggested that partners
have dramatically pushed the power density of SiC-based
power modules, which was evident in one of the slides that
demonstrated a galvanically isolated vehicle battery charger using a 1,200-V SiC-based high-frequency (more than
June 2014

z IEEE PowEr ElEctronIcs MagazInE

Table of Contents for the Digital Edition of IEEE Power Electronics Magazine - June 2014