Single-wire controlling device and method for holding current maintenance

A single-wire controlling device and a single-wire controlling method for holding current maintenance are provided. The single-wire controlling method includes: chopping a power voltage on a first power line and outputting a chopping signal according to a user's control; performing a power factor correction to the chopping signal by a PFC circuit such that the load current flowing through a load is substantially equivalent to the chopping signal; and controlling the duty cycle of the PFC circuit to a maximum value such that the load current is greater than a holding current when the absolute value of the voltage difference between the voltage of the first power line and the voltage of the second power line is smaller than a threshold voltage.