Keeping pace with emerging solid-state lighting (SSL) applications can be difficult for design engineers, not only from an end-product standpoint, but at the component level as well. Design engineers are challenged to combine their optical expertise with thermal management, power, electronic, and mechanical packaging properties.
These properties are necessary to develop high-quality LED light fixtures that can meet consumer expectations - including long operating life, sufficient light output, warm-color light, and low power consumption.
A critical challenge from a SSL connector standpoint comes from the orientation of the PC boards in strip or linear lighting. In this application, the PCB’s are stacked end-to-end to create a specific length of LEDs to match the desired light output or specific fixture length. What makes this complex? The connectors need to both be horizontal, creating a coplanar interface. They also need to be small, carry higher current levels to drive the LEDs, and be single sided surface mountable so they can be used on any FR4 or metal core boards. And this is just the beginning.
The design engineering community has magnified the need for this type of unique connector system across a number of applications. While engineers concentrated their efforts on the optical and thermal management of their fixtures, the connectors system remained as a problem that was yet to be solved. Engineers were forced to select an existing connector system already on the market even though it did not meet all of their requirements. While these available connectors were functional in the applications they were plugged into, they were typically not the right size, configuration, or preferred performance level.
To meet required performance characteristics of the SSL market, connector manufacturers such as AVX have designed custom LED lighting connector systems for off-the-shelf availability. The foundation for the new family of SSL interconnects became the AVX 9159 Series 2-Piece, board-to-board, SMT connectors. Packaged around a new 5 amp, gold plated, beryllium copper spring contact, the connector system exceeds the demanding robustness and reliability requirements of the new lighting market. This includes an operating temperature range of -40°C to +125°C.
Historically, industrial grade connectors come in a variety of colors. Based on customer response, the preferred color for LED lighting applications is white so that the connector blends into the fixture. Thus AVX added this color option to the base standard features of the 9159 Series.
The LED plug and socket connectors, available in a 2p to 6p size range, enable boards to easily be plugged together with minimal LED pitch, which maximizes light output. Customer requests have led to the development of a wire-to-board version that brings the power and control signals onto the PCB without having to change the board level connector. In other words, engineers can design their LED boards with a single connector and footprint and not have to change the connector when it was used as a wired or PCB connection. This concept also allows the designer to build a single PCB with a socket on one end and a plug on the other for all applications. Regardless of where the board is used in the system, a single PCB can be built at significant savings to satisfy all configurations.
LED wired connectors provide the mechanical strength to support the wires connecting it to the outside world and an optional latching mechanism is available to ensure proper insertion of the wired plug to the mating PCB socket for harsh environment LED applications.
The next-generation of SSL connectors feature a unique design that allows a single LED board to be replaced in the field without the technician having to disassemble the entire string of PCB’s. From this customer request, a LED connector featuring a slide-top option was created. Compatible to the standard socket PCB board, the SSL connector’s moveable top slides open to allow the mating plug to be unmated. Once the board is replaced, the top would be latched closed in what is typically referred to as a Zero Insertion Force (ZIF) action. This feature offers a significant cost savings in the field, as a defective board is now easily replaceable, lowering maintenance and components costs.
Additional features have recently been added to the LED connector family designed specifically for the SSL market. For high shock and vibration applications a small locking clip was tooled to mechanically hold the plug and socket SMT connectors together. This stainless steel clip slides right into the back of the plug connector prior to mating the PCB’s. Once mated, the clip will latch over the socket insulator providing a secure and positive lock. AVX also developed a two-position shorting socket that plugs onto the final PCB to jumper or close the electrical loop in a string of boards. This connector has an integral latch to make sure it is mated securely onto the SMT plug. This continues the overriding theme to build a single PCB in volume and then provide the necessary options so that it can be positioned anywhere within the fixture.
In addition to the normal data sheets, sales drawings and product specifications, a specific application notes document has been created to explain how each of these individual products are used in a step-by-step format.
The energy cost savings of SSL is a driving force behind the increased development of LED lighting, especially in commercial and industrial applications such as outdoor lighting and signage where lights are on constantly. With components specifically designed for LED applications, performance, ease of implementation, energy savings, and overall costs will continue to get better. The evolution of LED connectors have been based upon customer and market demands. All of the connectors have been developed to meet application requirements with simplicity, modularity and reliability as the key driving factors. AVX is committed to the SSL market, and its technology roadmap contains leading edge passive electronic components and connectors to meet the demanding market requirements for the future lighting systems being designed today.
For more information, visit www.avx.com.