Until recently, low-power FPGAs were
about as oxymoronic as bipartisan cooperation
and bug-free code. But the FPGA
landscape is changing for the better as
more vendors can say with a straight face
that they offer low-power FPGAs without
having their marketing guy laughed out of
the room.
Not only that, but FPGAs also have
been getting more and more design wins
in battery-based portable applications in
which low power consumption is paramount,
such as cell phones and portable
navigation devices. Combined with their
inherent rapid prototyping capabilities,
this makes FPGAs an attractive alternative
over ASICs and ASSPs.
Rapid prototyping enables portable
device vendors to keep up with the frenzied
pace of innovation, where design
cycles may last only a few months. FPGAs
are additionally attractive because standards
evolve rapidly and vendors want to
offer the latest technology, such as touchdriven
GUIs.
The FPGA’s leap into new territories has
been made possible because many vendors
have added new process technologies
to attack leakage current issues. They also
have lowered the core operating voltage
to reduce static power consumption. And,
vendors are upgrading their tools to provide
feedback about power consumption
and can better assist with providing lower power consumption for a given design (see
the figure).
Actel has taken these steps and more
to reduce power consumption with its
Igloo family of FPGAs. These true (versus
hybrid) flash-based devices feature
considerably less power consumption
than their SRAM-based counterparts.
According to Actel, flash-based solutions
can reduce power consumption caused
by leakage current by two to four orders
of magnitude. Case in point, Actel offers
a device that consumes a mere 5 µW of
static power, compared to the several milliamps
used by SRAM-based FPGAs.
“Flash-based FPGAs also feature significantly
lower (total system) dynamic power
than their SRAM-based counterparts,”
said Fares Mubarak, senior vice president
of Actel. “Dynamic power is a function
of device architecture, design tools, and
operational voltage.” The Igloo family is
also available in a 4- by 4-mm ball-grid
array (BGA) package with a 0.4-mm ball
pitch. And since the family is flash-based,
no external configuration memory is
required, saving additional board space.
“Smaller than a kernel of corn, the new
Igloo FPGAs are an ideal solution for
power-sensitive, space-constrained handheld
devices such as smart phones, portable media players, secure mobile communications
devices, remote sensors,
security cameras, and portable medical
devices,” said Mubarak.
The Igloo family offers many other
power-saving innovations, such as
instant on. Its Flash*Freeze mode switches
between dynamic and static operating
modes. Tool-based features include a
power-driven (rather than timing-driven)
layout. The end result: “Total power
for Actel’s 1.2-V FPGAs is typically 60%
lower than competing FPGA suppliers,”
concluded Mubarak.
Actel has put together a list of 10 powersaving
techniques (see “10 FPGA Tricks
Provide Power-Saving Treats,” right). Sampling
now, the Actel Igloo 15,000-gate device
will be available in the second quarter for
$0.99 in volume.
