A power supply includes: a first switch arranged between an input power supplier and a load; a driving power supplier to receive input power through the first switch and to supply the input power to the load when a current mode of the load is a normal mode; and a power-saving power supplier connected to a power line branched from between the input power supplier and the first switch, the power-saving power supplier generating standby power when the current mode is a standby mode, and including a second switch connected to the power line, a charger to charge power transmitted through the second switch and to output the charged power as the standby power, a voltage detector to detect the voltage of the charged power, and a first controller to receive driving power from the charger and to control operation of the second switch according to the detected voltage.