Smart LED DC Module 20W, an Efficient Compact LED Solution


Valentin Kulikov at fulit

A DC fed LED module combines the most recent LED technology with a smart DC driver, offering a ready-made solution for fixture producers, researchers, and hobbyists. The module is populated on a metal core PCB, implementing both the LEDs and high efficiency driver, incorporating both thermal fold-back and dimming. Thermal fold-back and active control of the maximum temperature of the module pro-vides a great advantage. While the driver is small, it operates at high efficiency, above 94%, and accepts input voltages up to 60 VDC (as shown in Figure 1). In the event of a failed (shorted) LED, its efficiency is still high enough to keep the remaining LEDs operating correctly. If even more lighting reliability is desired, the module (upon request) can be provided with LED shunts, thus solving open LED failures.


Figure 1: Smart LED module efficiency characteristics

Several modules can be paralleled and connected to central or individual constant voltage 48 VDC power supplies, thus forming lighting fixtures or a system according to specific needs. The module is used conveniently with control accessories from FuturoLighting [1]. Because of the integral thermal fold back, the module itself will never get overheated, therefore its lifetime is not affected by inappropriate installation and inappropriate environments, i.e., it is thermally safe even without a heat sink. If the module temperature should become higher than a set temperature, the driver decreases current flowing to the LED’s, reducing power consumption and keeping the temperature constant. This is shown in Figure 2. This current change is continual and does not disturb visual perception.
Lamp intensity, flux, as well as module consumption can be controlled by dimming signals, either a fast PWM (0-5 V, from an MCU) or an Analog signal (regular dimmers 1-10 V, isolated). On request, there are several other control options available, including protected PWM input and different analogue signal levelling.

The smart LED module is assembled with Cree XT-E, with output flux > 2300 lm (LED hot efficiency >110 lm/W) @ Tsp = 70°C, CCT = 4000K, CRI >70. Based on customer needs we are able to populate modules with different LED brands including white, colour, IR and UV LEDs. 

The Module dimensions are 145x43 mm, with a total height only 4.1 mm, so as to fit into thin street optics 2x6 (shown in Figure 3.). 

The module is compatible with optics from Ledil, Carclo, and other manufacturers, and it can be customized on request, according to your needs, including dimensions and LED positioning. 


Figure 2: Smart LED module thermal foldback (used inappropriate sized heatsink

Fields of application

The module will find applications in Low Bay, High Bay, Street Lighting, wall washers, plant growing, UV curing, IR security vision and in other special purposes. The LED module is customizable and customers can select a specific LED brand, light colour (R, G, B, IR, UV, and their combination, for instance, for research and other scientific purposes), CCT, CRI, flux bin, and also drawing current (example, see Figure 5). Simply add a central or individual 48 VDC power supply and connect as many modules as needed to create a lighting system. The required power source should be sized to provide 22W to each, for example 4 Smart LED modules will need a minimum 90 W power supply.



Figure 3: Smart LED module fitted into 2x6 street optics (top), high bay optics (bottom)

Low voltage smart grid

These LED modules are suitable to form low voltage (48 VDC) grids involving dimming control, occupancy detection and other smart functionality. For example, a central SMPS of 480W can supply around 20 LED modules, providing above 46k lumen flux (from modules at Tsp = 70°C). Figure 4, shows a connection example using PWM signal across modules.


Figure 4: Low voltage grid with PWM dimming

Conclusion

These modules are a ready-made solution for everyone designing lighting fixtures and systems. The Smart DC LED module can be easily used to form low power up to high power fixtures for general lighting, plant growing, Sea life aquariums and many others. It is only required to connect an appropriate number of modules together and power them from a constant voltage power supply. Additionally, these modules control the maximum temperature, extending module life and minimizing temperature degradation and failures. Even a missing heat sink will not lead to a module overheating. Smart LED modules have dimming input that can be either PWM or Analog controlled. Additionally, proximity sensors can be connected to the DIMM input for presence detection and light switching. But the easiest way method of brightness control is to use a potentiometer and few low cost components to make provide dimming. More information can be found in the product Leaf letter [2ddsxxxxxx].


Figure 5: Customized LED module for sea life aquariums

 

[1]
Available controls: http://www.fulit.eu/controls.html
[2]
Smart DC LED module Leaf letter: http://www.fulit.eu/docs/smartdc20_lft.pdf

More information: fulit    Source: Bodo's Power Systems, August 2015