It’s reverse: you get a board that has a floppy interface on one side and a USB socket on the other. You plug in a USB drive and the board uses a file on the drive as the floppy disk, pretending to be a floppy Drive connected to the interface. It’s a little less convenient because you have to deal with disk images but it works without moving parts.
It’s probably not a good idea for actual use, but if you’d like to experiment: looks like the 3-pin devices U4 and U5 on the upper right provide feedback through the optocouplers next to the class Y cap north of the transformer. I bet those are LM431 voltage references (or similar). The passives around them provide filtering, but two of the resistors should form a resistor divider for the Ref pin (lower right pin if the single pin is on top). That divider sets the voltage.