Valentin Kulikov, Futuro Lighting
A smart DC LED module connects most recent LED technology together with smart DC drivers, offering a ready-made solution for fixture producers, researchers, and hobbyists. Such a module is usually populated on a metal-core PCB, implementing LEDs and a high-efficiency driver with thermal foldback and dimming. Advantages of a smart module include this on-board thermal foldback, with active control of the maximum temperature of the module.
The implemented driver has small dimensions, and operates at an efficiency above 94%, and accepts input voltages up to 60 VDC, as shown in Figure 1. Even in the situation of failed (shorted) LEDs, its efficiency is still high enough to keep remaining LEDs operating correctly (Red and blue characteristic). For increasing module reliability, a smart module can be assembled with LED shunts, which solve open LEDs failures.
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Fig.1. Smart LED module efficiency characteristics
Three marked solder terminals enable connection of the module to the power supply and control. Several modules can be parallelized and connected to a central or individual constant voltage power supply (48VDC) and thus forming a lighting fixture or system according any specific needs. This module can be easily used together with control accessories. The implemented thermal fold back module itself will not overheat and therefore its lifetime is not affected by inappropriate installation and inappropriate environment (thermally safe even without heat sink). Once module temperature is higher than set temperature (Tset) driver decreases current flowing to LEDs, thus reducing power consumption and keeping the temperature constant, as shown in Figure 2. This current change is continual and not disturbing visual perception.
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Fig.2. Smart LED module thermal foldback
￼The flux amount as well as the module consumption can be controlled by a dimming signal, that can be fast PWM (0-5 V, from MCU) or Analog (regular dimmers 1-10 V, isolated). On request there are several other control options, including protected PWM input and different analogue signal leveling.
From price point of view such smart LED module assembled e.g. with Cree XT-E with output flux > 2300 lm (LED hot efficiency >110 lm/W) @ Tsp = 70°C, CCT = 4000K, CRI >70, ranges at 14,9E @ 1k quantity. Based on customer needs one can populate modules with different LED brands including white, color, IR and UV LEDs.
Module has dimensions of 145x43 mm and total height only 4,1 mm with goal to fit into thin street optics 2x6 (shown in Figure 3.). Distance between LEDs is 25,4 mm and MCPCB thickness is 1,5 mm. Module is compatible with optics from Ledil, Carclo, and other producers, and it can be accommodated, according to your needs, on request including dimensions and LEDs positioning.
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Fig.3. Smart LED module fitted into 2x6 street optics
Fields of application
￼The module will find application in Low bay, High Bay, Street Lighting, wall washers, plant growing, UV curing, IR security vision and in other special purposes. LED module is customizable and customer can select LED brand, light color (R, G, B, IR, UV, and their combination for e.g. research and other scientific purposes), CCT, CRI, flux bin, and drawing current as well. Just need to add central or individual 48 VDC power supply and connect as many modules as you need to create lighting system. Required power source should be calculated as modules count x 22W, for example 4 Smart LED modules will need min 90W power supply.
Ready-made solution for everyone, designing lighting fixtures and systems was shown in this article. 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. You just need connect appropriate amount of modules together and power them from constant voltage power supply.
Additionally, these modules control maximum temperature extending LED module lifetime and minimizes temperature degradation and failures. Even missing heat sink will not lead to module overheat and destroy. Smart LED modules have dimming input that can be or PWM or analog controlled. Additionally, proximity sensor can be connected to DIMM input for presence detection and light switching. The easiest way how to control module brightness is to use potentiometer and few low cost components to make it dimmable.