A power supplying apparatus having a power saving function and a method of
supplying power with a power saving function. An auxiliary power
generator generates auxiliary power in response to a cutoff signal. A
main power generator senses the generation of the auxiliary power and
generates main power in response to the sensed result and a first state
of a control signal supplied by a set which performs an intrinsic
function. Absent the power cutoff signal, the set performs the intrinsic
function in response to the main power and stands by to perform the
intrinsic function in response to the auxiliary power. A second state of
the control signal places the power supplying apparatus in a power saving
mode during which the set may communicate with another circuit. If the
cutoff signal is supplied during performance of the intrinsic function,
main power is sustained until the intrinsic function is completed.