Publication date: 15 June 2010
LED lighting is today’s big thing, and deservedly so. High Brightness LED manufacturers have successfully increased the luminous flux from successive generations of devices to levels now sufficient to allow a wide range of applications and markets to benefit from the many practical advantages of solid-state lighting.
The high efficiency of today’s power LEDs, in terms of lumens per Watt, is a major attraction, particularly for home owners and businesses looking to control their carbon emissions as well as spiralling utility bills. There are, however, many further exciting aspects to this lighting revolution; advantages such as smaller dimensions, lower operating voltages, longer lifetimes, opportunities for processor-controlled lighting effects, and surface-mount package technology of power LEDs promise to change the way lamps and lighting are designed and used.
For the technology to deliver its full potential, however, producers of supporting components such as interconnects, passives, power supplies and thermal management products must follow the example set by LED and control IC manufacturers; in typical semiconductor marketing style, they have been diligent in preparing complete, turnkey solutions for their customers.
Lighting design using Power LEDs is fundamentally different to building conventional incandescent lamps. An LED light comprises multiple individual emitters connected in series, and a suitable ballast or controller must maintain a constant current to achieve the desired level of illumination. This has implications regarding the capacitive and resistive components used in conjunction with the semiconductor devices managing the current and voltage supplied to the LED string. Whereas components for conventional ballasts are typically chosen on price, solid-state technology requires higher-quality components to withstand high thermal loads and support the significantly longer operating lifetimes. Some designers are specifying higher-performing capacitors featured for demanding applications such as laptop computers to ensure the thermal stability and reliability required in the solid-state lighting application space. Temperature-related effects also compromise the performance of conventional resistors when controlling LED driving current, demanding careful consideration of the temperature coefficient (TCR) when selecting suitable components.
In applications requiring an off-board power supply, customers need access to a box-level solution. These are often deployed at the installation stage; hence low volumes of units capable of satisfying individual power demands are required. Power supply vendors and distributors offer constant-current or constant-voltage AC/DC modules, at voltage and power levels suitable for LED-lighting applications, to provide “plug-and-play” power solutions for their customers including lighting designers and installer communities.
Heatsinking to maintain lifetime performance and reliability is another key aspect of any solid-state lighting solution, which may be satisfied using an off-the-shelf unit, but often demands a custom solution. A good technical distributor can help designers and installers realise unique solutions meeting the exact mechanical dimensions and thermal performance required for a given application.
When it comes to fitting solid-state lighting solutions in the field, installers need access to a variety of suitable interconnection solutions. Ease of assembly, robustness, and solutions for connecting large numbers of PCBs or standalone modules are extremely important to enable applications such as architectural lighting, signage, emergency lighting and mood lighting to derive the maximum benefit from the versatility and efficiency of power-LED technology.
Interconnect solutions conceived for the LED era are entering the market, including specific module-to-module, board-to-board, wire-to-board and wire-to-wire interconnects in current and voltage ratings for LED applications. This helps installers achieve quick space-efficient assembly and installation, as well as high reliability. Among these, miniature wiring systems optimised for rapid assembly in confined spaces such as inside cabinets or appliances can be procured in custom lengths and as kits of components or as complete cable/connector assemblies ready to install in the field.
Clearly, although power LED technology has proved its credentials, there is still some way to go as far as system-level components are concerned. Installer communities, in particular, need a greater choice of products and services matching special requirements of solid-state lighting applications. Here is an opportunity for component OEMs and their technical channel partners to build an even stronger case for solid-state lighting.
