LED driver
Due to the diode characteristic of LEDs, even a small change in the supply voltage results in a large change in the diode current. In addition, the diode characteristic curve depends on the temperature of the LEDs. Therefore, an LED that is operated at too high a voltage without current limitation can quickly self-destruct(thermal runaway).
For this reason, LED lighting is operated almost exclusively with a constant current. This can be implemented with losses and to a certain extent voltage-dependent using series resistors or with more technical effort, but more efficiently and voltage-stable using appropriate controllers.
The simplest variant for this are special LED drivers or constant current sources. These usually supply a fixed standard current value and often also offer the option of dimming the LED lighting using a control voltage or PWM signal.
LED drivers with low power are often designed as controllable resistors. These work in a similar way to the series resistors mentioned above, but without the constant current being dependent on the supply voltage.
LED drivers with a higher output are often designed as switching regulators. These are significantly more complex than the methods mentioned so far and usually require a much larger installation space. However, they can achieve an efficiency of well over 90%.
The high-end version is the fully integrated lighting controller. Here, an adjustable constant current controller is linked to a user controller so that the lighting properties can be configured via digital communication protocols or web interfaces.
