Connected Intelligent LED Lighting Networks: Intelligent Lighting Integrated Within Smart Buildings

(Source: zu difeng/Shutterstock.com)

By Paul Golata, Mouser Electronics

Today’s LED lighting does much more than illuminate otherwise dark spaces. When combined with low voltage IP-based infrastructure in a connected intelligent network, LED lighting becomes part of a powerful network of systems that work cooperatively to collect, analyze, manage, control, and respond to set objectives and real-time sensor feedback. The resulting “smart building” is more holistic in its operational performance because it can dynamically respond to operating issues, thereby increasing efficiency and saving both power and costs.

How does integrated intelligent lighting work with other systems? And what technologies are needed to integrate systems and maximize benefits? This article explores connected intelligent lighting and discusses infrastructure technologies.

Intelligent LED Lighting Networks

The basic premise behind connected intelligent LED networks is to have lighting control go from a centralized and relatively universal approach across a large area of the building space and to change it over to a solution that’s tailored to the specific needs of smaller segments within the building. What’s more, because the lighting is part of an intelligent network, the lighting integrates with—and can respond to—other components on the network. This is especially valuable in commercial office buildings, healthcare facilities, warehouses, manufacturing and industrial facilities, and similar large or multipurpose spaces where a one-size-fits-all approach is ineffective or inefficient.

Imagine a building that’s controlled through automated heating, ventilation, and air conditioning (HVAC). The HVAC monitors and adjusts the temperature to make the surroundings suitable for human comfort and machine performance, as well as optimal efficiencies and cost. A connected intelligent LED lighting network would allow lighting to be synchronized into these same set of objectives. This actively couples lighting response with environmental climate control. As a result, connected intelligent lighting networks increase the ability for the network users to adjust light to increase human productivity, positive mood, concentration, and well-being. It can respond to potential advantages achieved by adjusting light in synchronization with the natural human circadian cycle and additionally by reducing or increasing the required light depending on the amount of sunlight coming through external windows.

LED Lighting and PoE

The key technology behind intelligent LED lighting networks is Power over Internet (PoE), which brings the low-voltage cabling and equipment that connect Internet of Things (IoT) assets to LED fixtures. PoE is simple and available because of the success of IP-based infrastructure platforms. By using PoE as the artery of the LED lighting power and control system, lighting is incorporated into the building as an IoT asset. Besides the tremendous advantage of providing power and data over a single-layer infrastructure, PoE is also less costly than copper cable. As Figure 1 shows, PoE system architecture includes the following devices, discussed in the next sections:

• PoE gateways
• LED light fixtures
• LED lights
• LED smart drivers
• LED cable harnesses
• Sensors
• Wireless switches and dimmers

Figure 1: PoE system architecture includes gateways, fixtures, lights, drivers, cable harnesses, sensors, and wireless switches and dimmers. (Source: Molex Transcend® Network Connected Lighting)

PoE Gateways

While computers and network interfaces control the management layer of the PoE network, the start of any integrated LED lighting system relies greatly on the device layer and the level of system components used to make the network. A PoE gateway is the device at the heart of the system. These gateways connect to, control, and power the light fixture luminaries that operate the LEDs. They are able to control LED lighting functions, including dimming, color tuning, and sensor reporting. These gateways are capable of delivering up to 60W. In cases where more wattage is needed, such as in high bay lighting, AC line voltage (120VAC–277VAC) is still required, wherein the devices can be controlled by a wireless line voltage relay.

In the IP industry, the standards derived from the Advanced Telecommunications Computing Architecture (ATCA or AdvancedTCA) call out for 48VDC. Because of this standard, it is natural to provide POE gateways that are configured to one of the following configurations:

• Unregulated 48VDC
• Constant voltage 24VDC/48VDC
• Constant current

Wireless PoE gateways that conform to IEEE 802 standards may also be used. They run at standard frequencies (902MHz, North America; 868MHz, Europe). Commonly, they have an effective range of about 15m. They enable secure two-way communication for control status of multiple wireless devices without designers needing to have cause for concern with interference happening with other devices.

LED Light Fixtures

The LED light fixture itself is a critical and enabling component of the system. At its core, the fixture relies on the selection of the specific illuminating LED itself. In LED lighting systems that are not intelligently connected and networked, the LEDs used are substituted for traditional lights. The inherent superior technological efficiencies of LEDs relative to incandescent or fluorescent lights provide the efficiency benefits. However, connected intelligent lighting systems ratchet the whole system up a level. They take and add PoE gateways, lighting control sensors, and advanced network-managed software systems to provide a total environment that adds significant feedback and control into the system. This enhancement makes the light themselves human centric and capable of being controlled based upon data, analysis, and decision criteria of the network user.

LED Lights

LED manufactures are constantly improving LEDs by increasing their efficacy (lm/W) and reducing the cost per lumen ($/lm). Examples of LED manufactures that provide excellent products for light fixture manufactures abound:

• Cree, a leader in illumination LEDs created the XLAMP XHP70.2 Extreme High Power LED, which deliver low system cost through high lumen density, reliability, and color consistency. Improvements in lumen density, voltage characteristics, reliability, and optical performance in a 7.0mm x 7.0mm package.
• Lumileds has developed the LUXEON MX LED Module which is a high-power, multi-die emitter, enabling cost-effective, high-reliability fixtures for High Bay and Outdoor applications. It boasts up to 150lm/W efficacy in a 12VDC configuration to produce up to 1,200 lumens at 85°C.
• OSRAM Opto Semiconductors makes the DURIS E 2835 LED, which combines good efficacy and a wide viewing angle into a compact 2.8mm x 3.5mm Plastic Leaded Chip Carrier (PLCC) package. These surface-mount LEDs are available with a Correlated Color Temperature (CCT) of 2700K to 6500K.

Additional useful products include these:

• Surge protectors: Littelfuse manufactures the PLED6N Open LED Protector, which provides a switching electronic shunt path when an LED in an LED string fails as an open circuit. Its low height profile (1.1mm) makes it compatible with 1W rated LEDs with a nominal 350mA current at 3VDC (1W).
• Connectors: Molex brings connector innovation forward with the Molex Lite-TrapTM and Mini Lite-TrapTM SMT Wire-to-Board Connector System, Push-Button Type. These offer profile heights down to 2.65mm, easy wire removal, low wire insertion, and high wire retention forces for thin LED lighting-module applications. Its ultra-thin profile prevents shadowing in LED lighting applications.
• LED drivers: Texas Instruments makes the TPS92515/TPS92515-Q1 2A LED drivers, which provide compact monolithic switching regulators integrating a low resistance N-Channel MOSFET. Intended for high-brightness LED lighting applications where efficiency, high bandwidth, PWM and/or analog dimming are important. Infineon is a global leader in MOSFETs. Additionally, Infineon provides the CoolMOS® CE whereby its excellent efficiency, ease-of-use, and EMI performance at an attractive cost make the series the product of choice for LED drivers or LED tubes. They can be applied in buck, flyback, PFC, and LLC topology.

Smart LED Drivers

Intelligent LED drivers supply the appropriate power and conditioning signals for the LED engine. After receiving control data and power from the PoE gateway, the LED driver can respond to information and drive tasks based upon a coordinated design, control, and management system emanating from the connected network. At present, they are available in single-channel or dual-channel configurations capable of driving LED lighting fixtures with constant currents at output voltages of 12VDC-42VDC and a maximum output power of 45W. They can be daisy-chained together so that that up to eight devices can be driven from a single PoE gateway.

LED Cable Harnesses

LED cable harnesses are not yet standard as a means of connecting smart LED drivers in order to provide the low voltage power distribution and data communication necessary to control LED lighting fixtures, sensors, and actuators. An excellent way to design and do so until these LED cable harnesses become industry standard is using Molex’s excellent solution for this application: Their new Micro-Fit 3.0 Interconnect System (Figure 2). This system is designed to meet the need for a high contact density signal or power connector. They are built with a miniature 3.00mm (0.118”) pitch, yet they retain many of the features found on larger power connectors and can carry up to 5.0A of current. These connectors are proven in their reliability, durability, and ease of use.

Figure 2: The Molex Micro-Fit™ 3.0 Interconnect System is reliable, durable, and easy to use. (Source: Mouser Electronics)

Sensors

Sensors are a necessary part of the control loop in order to enable the digital building. Sensors can be either wireless or wired, and they can be deployed and powered though the PoE gateway or integrated into the LED lighting fixture.

Wireless ambient light sensors are a commonly deployed device in this arrangement. They are self-powered through collecting light and performing energy harvesting, which makes them economical and reliable. They are capable of measuring and reporting to a central host the level of available natural light allowing the network to make real-time adjustments and decisions.

Other common types of sensors used in LED lighting networks include: Air quality, color temperature, humidity, passive infrared (PIR) motion/presence, on/off, proximity, power, and temperature.

Wireless Switches & Dimmers

Self-powered wireless wall switches and dimmers employ energy harvesting technology to communicate wirelessly with the PoE gateway, providing convenient control of lighting, temperature, and miscellaneous electric loads. The local switch/dimmer pads are self-powered and never require batteries because the simple act of pressing the rocker generates enough energy to send a wireless signal to gateway devices.

Conclusion

Intelligent and networked LED lighting systems are forming new ways to apply LED lighting in the world of smart buildings and information technology. These lighting systems require a variety of technologies, including gateways, fixtures, lights, smart drivers, cable harnesses, sensors, and wireless switches and dimmers. The future is bright as system-level intelligence converges with our working environments, enabling the smart building of tomorrow today.