The LED driving power supply is a voltage converter that converts the power supply into a specific voltage and current to drive the LED to emit light. The output of the LED driving power supply is mostly a constant current source that can change the voltage with the change of the forward voltage drop of the LED.

LED is very flexible to voltage changes. When the LED is working under a stable current, the voltage at both ends is usually between 3.0-3.6V. When the voltage applied to both ends is slightly unstable, the current at both ends will change drastically. At this time, the output power of the power supply is also drastically changed. If there is a sudden increase in the grid voltage, and a small output voltage change at this time, a large output current will be produced. At this time, the power will increase sharply and accidents will occur.

And the 18w LED driver selection method is because the load characteristics of the LED itself greatly affect the reliability of driving it with a switching power supply. The output of the switching power supply is not very clean and smooth DC voltage energy, but a very complex energy signal, which can be roughly regarded as stable.