12 Volt switching power supplies
24 Volt switching power supplies
5 Volt LED switching power supplies
LED constant current power supplies
Top hat rail power supplies
It is not advisable to operate an LED power supply continuously at 100% load. On the one hand, there is a risk that the inrush current of the lamps will blow the fuse in the transformer. Furthermore, the power supply unit could become hot, which in turn reduces the service life and could become a hazard. If you are unsure, please call us.
A power reserve of approx. 15% – 20% is recommended. If more lamps are to be connected later, the power reserve should be chosen accordingly higher. Always round up the power and always use the next larger power supply unit for safety’s sake.
The LED needs a DC voltage for its operation because it is a semiconductor that has a reverse and forward direction. So the polarity must not change, which is the case with AC voltage.
Every LED lamp or luminaire is internally connected in a combination of series/parallel connection of individual LEDs. This results in an addition of the voltage or current.
Power supply units are needed for this. On the one hand, these rectify the alternating voltage (AC) from our mains supply (direct voltage DC) and on the other hand, they provide the correspondingly required voltage (constant voltage) or current (constant current) to the LED. Common constant voltage power supplies provide voltages in the range of 12V or 24V (volts). Consumers are always connected in parallel (current adds up (A)). These are available from us in different wattages and designs from 12Watt, e.g. as a plug-in power supply unit, to 300W, which are integrated into the installation.
With constant current power supplies, a fixed current (A) of the power supply (also called driver) is provided on the output side. Here, the voltage adjusts itself within a predefined range.
Now why are there these two different types of power supplies, the answer to this can be found in the working range of the LED itself. The LED has a very small voltage range in which it can be operated, but a larger current range.
An LED can tolerate a maximum of 500mA at a permissible power of 16.5W (33V). If the power supply had a tolerance of only 10% (+/- 3V), this would already lead to premature failure, because in the worst case the voltage would then be 36.3V, as the input current would increase disproportionately (>800mA). This requires very precise power supplies with very small tolerances that generate exactly the required voltage in the working range. The manufacturing costs with such small tolerances drive the price up.
If we use a constant current power supply (driver) instead of a constant voltage, which sets the current and adjusts the voltage (33.6363V), we have a great advantage because despite the large tolerance, the working range of the LED is only shifted very slightly. Drivers with tolerances in the range of e.g. 10% (+/- 55mA) output current would only shift the power or the operating range very slightly.
The advantage of a constant current driver is lower manufacturing costs compared to constant voltage power supplies. The manufacturing costs are much lower because the tolerance window can be larger.
The power supply units are used in all areas where LEDs are used. Power supplies or drivers are always built into lamps.
However, constant voltage power supplies cannot be completely replaced by constant current drivers, as there are many applications that only work in conjunction with constant voltage. Many controllers on the market, for example, which are used between the power supply unit and the LED luminaire, run with constant voltage and are therefore indispensable.