The market size for high brightness (HB) LEDs is expected to reach
$12 billion in 2012 and grow to $20.2 billion by 2015 with a 30.6%
CAGR ramp (source: Strategies Unlimited). One of the key application
areas driving this significant growth in LEDs is their use in
automobile designs. Applications range from headlights, daytime
running lights, brake lights and turn signals, to instrument cluster
display backlighting, as well as all kinds of in-cabin vanity
Almost all new model cars offer LED daytime running lights (DRLs)
due to customer demands for stylistic preferences and safety
benefits. Hondaís 2013 Accord uses LED DRLs in most models and
offers LED headlights in both their touring and hybrid models (see
Figure 1). In order to maintain this impressive growth rate, LEDs
must not only offer enhanced reliability, reduced power consumption
and more compact form factors, they must also enable innovative
designs such as steerable headlights and antiglare dimming.
Furthermore, in an automotive environment, all of these improvements
must be optimized while also withstanding the rigors of the
relatively caustic automotive electrical and physical environment.
It goes without saying that these solutions must offer very low
profile, compact footprints while simultaneously enhancing overall
Although LEDs have been used in daytime running lights, brake
lights, turn signals and interior lighting for several years,
headlamp specific applications are relatively new. Currently, only a
handful of production vehicles are offered with LED headlamps,
including the Honda Accord, Audi A8 and R8, Lexusís LS600h and
RX450h, the Toyota Prius, Cadillacís Escalade and Porsche's Cayenne.
Some industry estimates indicate that the current LED headlamp
market is approximately $1B for 2012 and is expected to surpass $2B
by 2014 and continue to grow exponentially.
One of the biggest challenges for automotive lighting systems
designers is how to optimize all the benefits of the latest
generation of HB LEDs. HB LEDs require an accurate and efficient DC
current source with a means for dimming and must offer a variety of
protection features. Additionally, these LED driver ICs must be
designed to address these requirements under a wide variety of
As a result, power solutions must be highly efficient, robust in
features and reliability while being very compact and cost
effective. Arguably, the most demanding applications for driving HB
LEDs are found in automotive forward lighting applications, in
both DRLs and headlamps as they are subjected to the rigors of the
automotive electrical environment, must deliver high power,
typically between 15W to 75W, and must fit into very space
constrained enclosures, all while maintaining an attractive cost
Figure 1. 2013 Honda Accord
Touring/Hybrid LED DRL & Headlamp
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