SemiSouth Laboratories Announces Efficiency Improvement in Solar Inverter With SiC...

SemiSouth Laboratories Announces Efficiency Improvement in Solar Inverter With SiC JFET

Enhancement-Mode JFET Eliminates 50% of Energy Losses in Power
Semiconductors
AUSTIN, Texas--(Business Wire)--
SemiSouth Laboratories, Inc. and the Center for Advanced Vehicle
Systems (CAVS) at Mississippi State University announced today that
SemiSouth's enhancement-mode silicon carbide (SiC) Junction Field
Effect Transistor (JFET) significantly improved the efficiency of an
off-the-shelf inverter commonly used in residential and commercial
solar power energy systems. CAVS provided guidance and precision test
equipment required to measure and validate the efficiency improvement.

CAVS validated that by replacing the existing silicon transistors
with SemiSouth's enhancement-mode SiC JFETs -- the inverter realized
reduced losses in the power semiconductors by as much as 50%. Most
significantly, CAVS used the JFETs as "drop-in" replacements for the
silicon devices, making no design changes to the inverter before
inserting the SemiSouth components. The grid connected, low-frequency
isolated inverter, purchased from commercial inventory of a leading
solar inverter provider, was designed with conventional silicon
Insulated Gate Bipolar Transistors (IGBTs). Dr. Rand German, Director
of CAVS and Professor of Mechanical Engineering at MSU, said of this
collaboration "CAVS is putting a major emphasis on positioning itself
for a lead in automotive power electronics R&D. This result validates
our belief that developing and testing applications for silicon
carbide power electronics through our partnership with SemiSouth is
leading to breakthroughs in energy efficiency."

Beyond the dramatic reduction in both conduction and switching
losses, the use of SiC JFETs as "drop-in" replacements to achieve the
efficiency gains is unprecedented. Robin Kelley, an applications
engineer for SemiSouth, said, "All that was necessary to drop-in the
enhancement-mode JFETs was the addition of a few passive components in
the control circuit to take into consideration the change in threshold
voltage between the original IGBTs and these JFETs. We started the
inverter and it ran without any problems." With this simple change,
immediate improvement with respect to performance and efficiency were
realized. This serves to open the door for additional modification to
fully take advantage of the SemiSouth device that will yield
additional improvements not only in performance and efficiency, but
also in overall system reliability.

Dr. Jeff Casady, SemiSouth's Chief Technical Officer, described
the enhancement-mode SiC JFET as "cheaper to produce, smaller than any
comparable silicon or silicon-carbide transistor, and free of
reliability concerns with gate-oxides that have plagued more
conventional approaches to develop an enhancement-mode field effect
transistor using silicon carbide."

This new enhancement-mode JFET can be used as a direct replacement
for silicon MOSFET's and IGBT's in virtually any off-the-shelf
converter or inverter design. Vess Johnson, SemiSouth's President and
CEO, said, "The fact that the JFET's can be used as a drop-in
replacement means that the barrier to entry has been greatly reduced
and that designers working with these devices will be able to see
immediate performance and efficiency improvements and will be able to
drive new and better products to market much faster."

About SemiSouth Laboratories, Inc.

Founded in 2000, with headquarters in Austin, Texas and
manufacturing in Starkville, Mississippi, SemiSouth is a privately
held silicon carbide (SiC) based semiconductor company. As an industry
leader in the development and manufacture of SiC electrical components
and materials for high-power, high-efficiency, harsh-environment power
management applications, SemiSouth provides discrete power devices and
SiC epiwafers. SiC-based semiconductor devices offer significant
advantages over competing products based on silicon and other
semiconductor materials for power management applications.

SemiSouth and the SemiSouth logo are trademarks of SemiSouth,
Laboratories, Inc. All other company or product names are the
registered trademarks or trademarks of their respective owners. For
more information, visit us on the website at http://www.semisouth.com

SemiSouth Laboratories, Inc.
Michele Grissett, 1-662-324-7607
michele.grissett@semisouth.com

Copyright Business Wire 2008