The use of external power supplies (EPS) has been growing significantly over the past three decades. California was the first to have its government organization put minimum legal requirements on the energy efficiency of the EPSs, which istorically had poor efficiency.
The U.S. Federal Government and other international
governments followed California’s decision by initially
introducing voluntary requirements, which turned into
mandatory requirements a few years later.
These government entities have been gradually raising the
bar since nearly 15 years ago, and the latest energy efficiency
standards are not the last. We will briefly overview the history
of power supply efficiency requirements and their impacts.
We will outline the major aspects of the latest Department of
Energy (DOE) efficiency standard, which is DOE level VI,
and compare it with the latest European efficiency standards
COC Tier-1 and Tier- 2. We conclude with possible upcoming
requirement updates and changes in the next version of the
DOE standard, which is due as early as 2 years.
In the 1990s, the use of electronic devices started growing
exponentially. These electronic devices mostly used different
voltage magnitudes and types than the AC grid voltage, and
therefore, required power supplies to convert the grid voltage to
a suitable conditioned voltage for their use.
To step back, there are two types of power supplies, internal
power supplies (IPS), which are used inside kitchen appliances,
TVs, and desktop computers, and external power supplies
(EPS), also known as power adapters, which are used to deliver
power from the grid to laptop computers, mobile phones, game
consoles, and other electronic devices.
At that time, due to the proliferation of electronic devices,
National Resources Defense Council (NRDC) estimated
that there were more than 1 billion EPSs operating in
the United States alone, and of those, most were using an
inefficient design called linear regulator technology with the
average efficiency around 50 percent. Moreover, the power
consumption of the EPSs was substantial when the end device
was turned off or detached from the EPS (which is referred
to as “no-load” condition). This poor efficiency of EPSs was
not principally due to the lack of technology, since IPS could
gain considerably higher efficiencies by employing switched-mode circuits, but because of lower cost and lack of market
incentives. Studies showed that if the efficiency and no-load
power consumption of the EPS remained at the same level,
EPSs would be accountable for around 30 percent of the total
energy consumption over the next two decades.
Becomes Critical for
External Power Supplies
A NEW DEPARTMENT OF ENERGY
STANDARD TOUGHENS REGULATIONS
FOR PORTABLE POWER ADAPTERS.
BY NAVID RIAZMONTAZER, PH.D.,
SR. ELECTRICAL PROJECT ENGINEER,
Figure 1: External power supply (EPS) manufactured by Inventus Power.