Allow Kaoyi to introduce the basic knowledge for LED drivers for lighting power supply. Then you will easily understand what a LED driver is. Altering mains electricity to suitable specification for LED lamp use with no harm is the role LED driver is playing in the lighting system.
What is no flicker / flicker free? How does flicker affect human? Human eyes do not realize the change due to the high frequency but this constant switching actions do harm human eyes as if turning on and off lights continuously.