PoE Realizes LED Lighting Applications

Power over Ethernet (PoE) can transmit data and power on one cable. The convenience of this technology has been widely adopted by many smart devices, such as LED lighting applications in smart buildings, which is one of the best use cases of PoE technology. This article will show you the development of PoE technology and the product features of the PoE interface LED driver introduced by onsemi.

The New Generation PoE Technology Can Provide 90W Power

PoE is a technology that can transmit power and data to equipment through a twisted pair cable in Ethernet, so there is no need to build separate cables for data and power supply, and the complexity of system construction, installation time and material cost are greatly reduced.

PoE plays a key role in achieving the connectivity, bandwidth and power required by the connected devices behind the implementation of smart buildings, because in the installation of Internet of things devices, it is usually necessary to place the devices in locations where there may be no available power supply. PoE provides another way to power the devices in these locations and provides flexibility for adding, changing or removing connected devices.

The original IEEE 802.3af-2003 standard provides a guarantee of 15.4W DC power for PoE applications, but the stable power is only 12.95W, which is due to power loss in the twisted pair cable. The improved IEEE 802.3at-2009 PoE standard (i.e. PoE+) can provide equipment with power up to 25.5W. This 2009 standard does not allow equipment to use all four pairs of cables for power supply.

The IEEE 802.3bt PoE standard approved by the IEEE Standards Association mainly proposes some important improvements for the application of LED lighting systems. The main driving factor is that through the use of four pairs of network cables, up to 90W power can be transmitted on 100m long cables, which can connect multiple lamps with a daisy chain, to simplify the installation process, which makes LED lighting using PoE technology an achievable application.

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An PoE Interface LED Driver Supporting Visible Light Communication

The PoE interface LED driver, NCL31010, launched by onsemi, is a member of onsemi's Power over Ethernet - Powered Devices (PoE-PD) product family. It contains all elements required for the lighting system connected and managed through PoE design, including visible light communication and indoor positioning functions. It integrates an IEEE 802.3bt PoE-PD interface controller, dual step−down converter, and buck converter LED driver. NCL31010 has passed the certification of the IEEE802.3bt/at/af standard, which can provide more than 90W system power, support high-power applications (up to 90W PoE) and proprietary 100W+ applications.

The NCL31010 also integrates a current mode step−down DC/DC controller designed to operate as an LED driver. The efficient buck LED driver can support high bandwidth analog and PWM dimming down to zero current. In addition, it also includes two auxiliary DC-DC converters to power the system microcontrollers and sensors. It also includes high-precision metrology and diagnostic functions for measuring input and output current and voltage, LED or system temperature, and DC-DC voltage and current.

The NCL31010 integrates all functions required for operation in a PoE system, such as inrush phase detection, automatic classification, and current limitation. It has a built-in high-efficiency buck LED driver (97%), supports visible light communication capability (50KHz bandwidth), integrates high-precision metrology (±1%), and a synchronous buck DC/DC converter for main 3.3V system power supply and auxiliary power supply, and has an adjustable 2.5 to 24V buck converter. The adjustable switching frequency is 44.4 kHz to 1 MHz.

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Provide Complete Control and Diagnosis Functions

In addition, the NCL31010 also has an I2C or SPI serial interface (NCL31010I/NCL31010S), which can connect the communication, system power supply, measurement, and diagnosis functions in series. It can use the internal precision 2.4 V reference for deep dimming to zero with an accuracy of 0.1%, and has best in -class linearity. When the modulation bandwidth is high (~50 kHz), it can enable indoor positioning through visual light communication capability and support compliant with YellowDot™.

The internal DIM DAC of the NCL31010 can be used for independent LED control (warm boot) during the re-flashing of a microcontroller. It adopts low EMI reference design to prevent led short circuits, open circuit and over temperature, LED overvoltage/undervoltage and overcurrent protection, chip overcurrent protection, chip and LED over temperature protection, and diagnostic function for measuring voltage and current.

The NCL31010 can operate in the junction temperature range from -40 to +125. It provides a 48-pin QFN 7x7 package. The devices are Pb−Free and are ROHS compliant. It can be applied to connected LED lighting, visible light communication and indoor positioning. Common end products include intelligent LED luminaries, managed LED

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Highly Integrated PoE Interface Intelligent LED Driver Evaluation Kit

To speed up product development, onsemi launched the NCL31010GEVK, a PoE interface intelligent LED driver evaluation kit, which supports the IEEE 802.3bt standard and with active bridges. NCL310xx series intelligent LED drivers can be used for high-efficiency, single-channel or multi-channel and connected lighting applications. The NCL31010 is very suitable for visible light communication and managed lighting systems. It can handle 100W+ power. It adopts an IEEE802.3bt certified PoE-PD interface and efficient buck LED driver. It supports high linearity, high bandwidth analog, PWM and digital dimming, and can be as low as zero current.

The NCL31010 is highly integrated and provides two auxiliary DC-DC converters to power microcontrollers, sensors, and other peripheral devices, including accurate metrology for measuring and reporting input and output current and voltage, LED temperature and DC-DC voltage. A full range of fault protection and diagnosis can cover device, application and user safety.

The NCL31010GEVK evaluation kit includes the reference design of intelligent LED driver of the NCL31010REFGEVB PoE interface (1-inch), which is a reference design of the PoE connected lighting controller and has passed PoE certification of the Ethernet Alliance and is YellowDot™ ready. In addition, there is NCL31010AASGEVB, a PoE LED driver Arduino adapter expansion board, and an Ethernet cable (RJ45), which has efficient active bridges and Class 6/60W LED drive capability, supports RJ45 data pass through connector, communication and control interface, and EMI/EMC optimization functions.

Conclusion

The new generation PoE technology can support the application of 90W power, greatly improving its practicability, and making the application of connected LED lighting lamps with PoE technology possible. onsemi’s PoE interface LED driver introduced in this article will be one of the best choices for developing relevant applications, which is worth your further understanding and selection.

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