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Smart LED lighting systems in various
fields - from home to commercial
to public applications – are taking
off at great speed. The U.S. market
researcher IHS projects over 160
Million smart lighting systems to be
sold in commercial applications this
year, with a CAGR of over 40 percent
through 2018. This is due to their
inherent advantages, such as low
power consumption, dimmability
and choice of color, flexibility in size
and easiness of combining to form
LED strips. These capabilities are
key for creating attractive lighting
solutions according to the customers'
architectural
guidelines
and
preferences. One frequent problem
that industrial lighting designers have
when they are developing smart LED
solutions is not having the necessary
power supply expertise, which was
not a key competency before LED
lighting took off.
Another difficulty for inexperienced
LED lighting designers arises when
systems have to be designed for
various wattage levels. The complaint
heardmost often is that it takes lighting
product designers too long to respond
to different wattage specifications
because each single solution tends to
be customized. This implies devising
different semiconductor controller
circuits, along with different magnetic
components. The result is that LED
solutions for industrial and commercial
lighting systems tend to be expensive.
The commonly used driver solution
in LED lighting products is based on
switched mode power supply (SMPS)
technology. Although well proven and
reliable, SMPS-based drivers do not
offer the advantages of LED lighting
engines with newer Direct AC Drive
(DACD) technology.
The Flicker Problem
The DACD advantages, such as lower
cost, smaller form factor, much higher
performance and a longer system
lifetime are compelling. Yet DACD has
been slow to take off, particularly in
the commercial and industrial market
segments. A key reason is the issue
of flicker. Flick-er occurs when the
AC line to supply the LED system
goes through the zero crossing points
of its sinusoidal trajectory at twice
the powerline frequency of 100/120
Hz. This means the supply voltage
momentarily drops to zero and the
LEDs switch off, which sometimes
causes the effect of a perceptible
flicker.
Flicker is not always an issue, but
it can be problematic for offices,
schools, stores and other brightly lit
commercial and industrial spaces, as
well as for live video recordings and
smartphones.
DACD Solution Simplifies
Smart LED Lighting Design
John Wiggenhorn, Fairchild
30 l New-Tech Magazine Europe