LED Drivers

1. Temperature behavior
   in order to guarantee a uniform operation of the driver, the maximum temperature specifications of the manufacturers must be observed. Temperatures sometimes determine the lifetime of the LED drivers. Air circulation can positively influence the temperature behavior of a driver and thus increase the service life.
2. Withstand voltage and EMC
   IEC 61547 specifies the requirements for light bulbs in residential, commercial and small businesses. The standard specifies which immunity requirements must be met. In addition, the test voltage of the drivers is specified.
   EMC describes the electromagnetic compatibility for external interference signals and the immunity to line current and line voltage irregularities. The EN 55015 standard, which lists limit values and measuring methods, serves as the basis for compatibility between electronic devices.
3. The service life and failure rate
   before a driver is installed must be clarified, which components are connected with each other and how high the voltages of the LED modules used are. In practice, the components are ideally matched to each other so that the system does not suffer any damage from inferior components. Depending on the quality of the drivers, an operating time of ≥ 50,000 hours can be guaranteed. On average, the failure rate for such a high-quality driver is about 0.2 percent per 1,000 hours. Lower-value drivers have an increased failure rate with a lower total runtime.

4. Protection classes and test marks
for LED drivers are subject to various standards. A distinction is made between safety tests (EN 61347), EMC tests (EN 50015, EN 61547, EN 61000-3-2), performance tests (ED 62384) and energy consumption tests (EN 62442-3). The IP numbers indicate the degree of protection of the driver. Drivers verified with IP20 are suitable for installation of standard interior lights. Devices with IP65 are mostly used for outdoor lighting.

5. Protection class I and II
for devices of protection class I, all electrically conductive parts of the housing must be connected to the protective conductor system.

Devices of protection class II have a reinforced or double insulation between the mains circuit and the metal housing. When using cables with a protective earth conductor, it must not be connected to the housing.

Installation of LED drivers
basically exists two types of mounting. On the one hand, there is a fixed mounting in the lights or in the housing of the light module, on the other hand, the drivers can be installed independantly in an intermediate ceiling. For independant electrical equipment, stricter EMC testing guidelines apply.

Are there also drivers or transformers that can be used to dim LED modules?

In contrast to conventional incandescent or halogen lamps, the brightness of an LED lamp cannot be reduced so easily. For conventional light sources, a lower voltage is simply sufficient. LEDs, on the other hand, flicker or switch off completely when the voltage falls below a certain level.

Today, pulse width modulation (PWM) is usually used to dim LEDs. Corresponding electronic modules switch the supply voltage on and off at a high frequency that is imperceptible to the eye - depending on the desired brightness. The circuits can be found both within dimmable LED lamps or integrated into dimmable LED drivers. In the latter case, attention must be paid to the designation "dimmable".