However, at midday, the temperature is higher, and the color temperature is cooler and whiter.
Figure 1 shows the color temperature relationship from 1000K to 10000K. The lower the color temperature value, the redder the color; the higher the color temperature value, the bluer the color.
Figure 1. Color Temperature.
Lamps with a single color temperature are not well-suited to the different living and working circumstances of people, because these needs vary depending on the situation.
As we see in Figure 2, for hotel room lighting, cool or neutral white light is preferable for reading and communicating during the day, while warm light can alleviate physical and mental fatigue, improving sleep quality at night.
Undoubtedly, LED luminaires with adjustable color temperature are becoming increasingly popular in residential, hospitality, office, and commercial lighting environments because they offer more personalized lighting that meets all these needs at different times.
Figure 2 Hotel room lighting.
As we see in figure 3, LED luminaires with adjustable color temperature and brightness use two light output sources: cool color temperature (6500K) and warm (2700K), each of which is relatively independent.
Figure 3. Method of driving adjustable color temperature in LED accessories
As shown in Figure 4, the color temperature can be adjusted by modifying the trigger current of each light source. When a specific color temperature is desired, the brightness can be adjusted by setting the conduction current of the two light sources in the same ratio.
Figure 4. Color temperature and current value curve
With the development and advancement of the lighting industry, digitally dimmable LED drivers ensure that color temperature and brightness settings do not interfere with each other. This design has gradually replaced the "constant voltage source + dual DC/DC output module" as a new driving method focused on creating a smart, comfortable, and human-centered lighting environment.
OLFER Electronics and MEAN WELL have launched a smart power supply, the LCM-40TW, compatible with DALI2 and featuring adjustable color temperature and brightness.
Figure 5 DALI-2 Intelligent Lighting
The LCM-40TW, distributed in Spain and Portugal by Electrónica OLFER, is an LED driver with two outputs for dimming brightness and color temperature (Dynamic White - Tunable White). It operates in dual-channel 40W constant current mode, with a DIP switch that can be configured for either DALI DT6 (LED lighting control device) or DT8 (color temperature control device). It also offers selectable current output via a micro-switch (500 to 1050mA). This device allows users to adjust the color temperature and brightness with a simple switch.
A smart lighting control solution.
Author: Cunhui Wei / MEAN WELL Technical Service Center
Marketing Department OLFER Electronics
