A key aspect to the use of LEDs for lighting is that power requirements are significantly different than for compact fluorescent and incandescent bulbs. Whereas the latter use alternating current and are voltage sensitive, the former use direct current and are current sensitive. Several manufacturers are offering new types of connectors specifically designed to work with SSL applications. This article reviews some of the latest products and highlights the key features they bring to the designer. JAE ES5 series
For simple wired interconnection, the ES5 series from Japan Aviation Electronics Industry (JAE) is a compact, low-profile connector system for a single interconnection using 2- to 24-AWG stranded wire. The system consists of a receptacle for board mounting and a plug that crimps onto the stranded wire cable. In addition to LED lighting, the connectors are suited for LCD-backlighting and tablet-PC applications.
Figure 1: The ES5 series from Japan Aviation Electronics Industry (JAE) is a compact, low-profile connector system for a single, stranded-wire-to-board interconnection.
The low-profile system has a 1.6 mm mounting height and does not have insulation. The connectors can be mated and unmated at least 20 times, thanks to a detachable locking structure that is designed to prevent mismating. The connector system is rated for 4 A, has maximum contact resistance of 45 mΩ, and works over a temperature range from –40°C to 105°C. JST LEA and LEB series
JST Sales America provides a variety of connector systems for use with LEDs. Two examples are the LEA and LEB series. The LEA series for board-to-wire interconnection consists of a side-entry header SMT receptacle and a plug that accepts 22- to 30-AWG wire to create two separate circuits. Mounted on a pc-board, the system has a height of just 3 mm. The plug has a 1.8 mm pitch while the receptacle has a 4.2 mm pitch. The system is rated for up to 300 V, and supports 3 A with 22-AWG wire. The receptacle has insertion / withdrawal guides for easy and secure insertion innovative locking device construction to prevent incomplete mating and accidental disconnection.
Figure 2: The LEA system from JST is a wire-to-board connector that can be used to route driver component wires to an LED board or interconnect boards with wires.
The LEB series for board-to-board and board-to-wire interconnection systems supports dual and single circuit connection. The system has a 4.0 mm pitch and supports 22- to 26-AWG wires; voltage rating is 300 V and with 22-AWG wire the current rating is 3 A. The system has a profile height of 2.7 mm and is capable of absorbing the pc-board misalignment due to heat expansion in the connector pitch direction. The pc-board layout for the plug and the receptacle is the same.
Figure 3: JST’s LEB system offers single- and dual-circuit board-to-board and board-to-wire interconnection options. AVX 9159 series
Specifically designed for SSL applications requiring coplanar (horizontal-to-horizontal) pc-board mating, such as in tube lighting systems, the 9159 series of board-to-board interconnect system allows two printed-circuit boards to be mated end to end to creating strips of LED lighting. Single-sided SMT connectors, they suit both FR4 and metal boards that must be butted together to minimize separation, providing a 5 A current rating in a small, 3-mm-high package. The system also accepts wire connections.
Figure 4: Specifically designed for SSL, the 9159 series interconnect system allows two printed-circuit boards to be mated end to end to create strips of LED lighting.
The connectors are available with white or black insulation, in versions with two to six pins with gold-plated beryllium copper receptacle contacts for harsh environments. Components in the 9159 series include a cable plug for wire-to-board applications, a two-piece horizontal socket, a ZIF-style top-load socket, a two-position shorting socket, and a retaining clip that latches board-to-board connectors together. Hirose Electric DF59
While it can be used in other traditional board-to-wire applications, the DF59 connector system from Hirose Electric is extremely effective in LED lighting applications. The system provides for both board-to-wire and board-to-board interconnection, and has components to support two-, three-, and four-circuit systems.
Figure 5: The DF59 connector system from Hirose Electric consists of four types of components: the board-mount receptacle (upper left), the wire plug (upper right), the receptacle-to receptacle, or board-to-board, connector (lower left), and the short plug (lower left). Various components support two-, three-, and four-circuit systems.
A receptacle that mounts on a pc board can mate with both board-to-wire and board to wire connectors, as well as a short-circuit pin connector that lets users terminate an open circuit, typically at the end of a series of connected circuit boards. The swing-lock mechanism on all the connectors employs both a positive and friction lock to help prevent the cable assembly from unmating in demanding applications (such as high vibration), and gold-plated dual points of contact ensure reliable connection.
The board-to-board connector can be used to connect multiple boards together in a co-planar arrangement. It provides a “stress-free” contact, in that it floats ± 0.5-mm in the x, y, and z dimensions to allow for thermal expansion. Connectors have a 3 A current rating, 2 mm pitch, mated height of just 2.48 mm, and temperature rating to 105°C. Nector S Line
Unlike the previous connector systems, the Nector S Line from TE Connectivity is aimed at a higher level of subsystem interconnection. The line provides a system of connectors, as well as cables, for power-to-luminaire connection, especially where a power connection and coupling between lamps is needed. Targeted applications include lighting wiring in offices, kitchens, bathrooms, display cabinets, mountable lightings, and shop and household furniture.
Figure 6: The Nector S Line from TE Connectivity provides a system of connectors, as well as cables, for power-to-luminaire connection, especially where a power connection and coupling between lamps is needed.
Whether it is 250 V, 125 V, or a low voltage application, these plug-and-play connectors can expand a lighting system beyond the wall outlet. Designed to meet the lighting industry’s need for a compact, easy-to-install, plug-and-play interconnect solution, the system is built around a basic 7.5 mm connector that easily fits in an 8 mm opening, much smaller than the opening required for other connectors.