They not only included the switching controller,
they also had a power transistor on a
monolithic device. A high-efficiency power
supply could now be built with very few external
components (only an inductor, a capacitor,
and a Schottky diode). Engineers could finally
improve on their power supplies with far better
efficiency than the older linear regulators. They
could also do magical things like invert voltages
to make the negative values required by
line drivers or other analog sections.
The energy crisis of the early 21st century
had not yet arrived, so power was mostly taken
for granted. Yes, hard-disk drives were improving
on their densities and processors were making
great strides, but the power requirements
still weren’t a major concern. If your product
had an electrical cord, you assumed you had
at least 2000 W of available power to run your
system. Those were the days!
Today’s Design Considerations
It’s no longer a luxury to provide efficiency.
It’s expected. Systems not only need to provide
their function, they also must do it with the
fewest joules possible. Yes, we have components
like high-density FPGAs complete
with soft processor cores, supercomputer-like
microprocessors, high-density RAM, ultrahigh-
speed data converters, and amplifiers. But
it all takes power to run them. Soon, every electronic
product will have a sticker on its side that
spells out how much energy it will consume in
a year’s period. Energy is no longer a low-cost
commodity that’s taken for granted.
Design engineers today have a daunting
task—create systems that outperform their predecessors
while using less power. Okay, when
I was designing systems in the 1980s, my only
concern was to get my design to fit into the
box given to me by the mechanical engineers.
I might even have convinced them to make it
bigger if I needed more space. But not today.
Server farms using thousands of blade servers
are running 24/7 to provide uninterrupted
service to millions of customers worldwide.
Power is everything. In July of 2007, Ellacoya
Networks released data that showed YouTube
accounting for 10% of Internet bandwidth—
a staggering amount of power dedicated to
watching video over the Internet. The growth
of information in all forms is highly nonlinear
and increasing with every second, and so is the
power consumption associated with the storage
and delivery of that information.
Today, it would not be uncommon in an
engineering peer review to question the power
consumption before the functional implementation.
Power that goes into a system comes out
as heat and impacts both the cost of ownership
and the long-term reliability. Fans can fail,
components can overheat, and systems can go
down. By lowering the energy consumption of
a system, engineers gain both improved reliability
as well as lower energy costs.
But does saving 30 W in a server really matter?
Saving 30 W (possibly a 10% improvement
in the power supply or through improved
system architecture) in each of 10,000 servers
is a tremendous amount of power. If you
account for the energy requirements of the air
conditioning as well, the power can double.
The 30-W savings across 10,000 servers is
equivalent to the power required to run roughly
500 average U.S. homes for a year!
The Next Generation
Like today, the future of designing electronic
systems will rely heavily on computers.
Advances in software will give engineers many
alternative architectural approaches, all optimized
for their target specifications. Leading
those specifications will be power consumption,
and the semiconductor suppliers will be
pressured to provide tools that understand the
system requirements and suggest solutions— much like my old coworkers did in my
peer design reviews.
As systems continue to become
more complex, software will be key
in improving performance as well as
reducing power consumption. Expert
systems have long been the dream of
engineers—those automated systems
that effectively “bottle” the expertise
of hundreds of specialists. These systems
will analyze designs or possibly
suggest new designs based on the
requirements provided. I can envision
a day when engineers become so overwhelmed
by the details, they will come
to rely on a collective computer that
works the fine aspects while allowing
the designer to handle the big picture.
In the near term, there’s no doubt
that we rely more on the manufacturers
to supply either tools or complete
integrated solutions, making the creation
of systems much easier. Imagine
having to build a CPU from scratch.
Today, you can simply load it as a soft
core into an FPGA or buy it as a completely
self-contained device. FPGA
tools already allow you to budget your
power requirements. The simulations
calculate the estimated amount of
power a design needs running at a
particular clock frequency.
Additional online tools help digital
engineers become analog designers.
Once the digital sub-systems are complete,
these tools can help designers
build highly efficient power supplies
or a complete analog signal path. In
the future, such tools will be “aware”
of the entire system requirements and
provide online advice as engineers turn
to the manufacturers for assistance,
even if that assistance is from artificial
intelligence. Now that will be the day.