The LED drive power supply is a voltage converter that converts the power supply into a specific voltage and current to drive the LED to emit light. Generally, the input of the LED drive power includes high-voltage power frequency AC, low-voltage DC, high-voltage DC, low-voltage high-frequency AC (such as electronic transformer output) and so on. 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.