24 AEROSPACEMANUFACTURING | NOvEMbER 2009
electronics i lighting
voltages and forward voltages, which “Increasing integration reduces the
can further cause variations in LED overall component count, which is
colour and brightness too. National’s significant as each additional component
voltage regulators are said to provide the potentially reduces the lifetime/liability
benefit of constant current source to of an application,” he confirms. “Faster
single or arrays of LEDs, enabling colour time to market is becoming essential in
and brightness matching over a wide practically all applications.”
temperature range. To speed market entry, Richardson
National sees a customer demand for has received positive feedback from
reduced system size and weight, as well LED designers after the introduction of
as the ability to enhance controllability National’s WEBENCH LED Designer.
Harmonised cabin solutions: “The increasing value
and increase power efficiency. Its This free online design tool is said to
of in-flight comfort has become more noticeable,”
says Diehl’s van Geenen
systems application engineer for lighting, significantly accelerate design work,
Christopher Richardson, says that the helping engineers select from, and design
barriers customers must overcome in with, hundreds of high brightness LEDs
“LED technology will evolve order to get their product to market, in minutes. The tool offers instant access
into an international market entry “Are in finding an effective way of to the latest SPICE models, parametric
strategy as it progressively reaches communicating with all the LED lamps data and package information, enabling
wider endorsement,” he avows. “The to achieve the control of colour changing designers to simultaneously compare
economies of scale will lead to a market and fine dimming without adding more the performance of various devices in
concentration of suppliers and strongly wiring, which would mean added weight multiple circuit requirements.
influence the development of the and cost. Thermal management is always “Another way to shorten the design
manufacturer’s brand. However, it’s an important factor for SSL too as it cycle is through reference designs,” he
important to understand that in order to requires effective cooling and, in case concludes. “A number of manufacturers,
achieve an aesthetically beautiful cabin over-temperature occurs, a control loop including National, offer reference
atmosphere, it’s essential to master the to reduce power consumption and LED designs for many applications to give the
art of optics, electronics, hardware and current. Any overheating can significantly engineer a quick start. National’s LED
software first.” reduce the lifetime of the SSL.” Driver reference design library currently
Richardson reckons customers holds over 40 proven designs for various
Power behind the light want solutions that no longer require lighting applications.” y
More and more general lighting aluminium electrolytic capacitors www.diehl-aerospace.de
manufacturers are recognising the because they dry out and fail, making www.national.com
important role that the suppliers of them the limiting factor for longer
optics, power ICs and passives play due lifetime applications. “They also want the
mainly to increases in light output per die ability to change the colour temperature
achieved by power LED manufacturers of white light, or even change the
and the subsequent cost, performance, colour,” he adds. “This requires multiple
control and efficiency improvements. LEDs of different colours and demands a
Able to mix RGB light to create balance in the cost and complexity of the
ambient mood lighting in cabins, the electronic drive solution.”
growth of power LEDs into aerospace Whilst the demands for smaller
applications will require technical footprint, higher reliability/efficiency,
improvements at the avionics system and lower cost are ever present in SSL
level as well as at the power LEDs development, Richardson adds two more:
themselves, if SSL is to realise its increasing integration and faster time to
potential. market.
According to National Semiconductor,
all LEDs work best when driven with
a constant current source. This is
“Faster time to market is becoming essential in
because its colour can change when
practically all applications.”
small variations in driving current occur.
LEDs often support varying system
Christopher Richardson, National Semiconductor
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