Power supply device and power supply method thereof

A power supply device, comprising:

• an adjustment circuit, receiving an alternating current (AC) voltage source in an AC mode and receiving a direct current (DC) voltage source in a DC mode, wherein the adjustment circuit comprises a plurality of voltage conversion circuits, and the plurality of voltage conversion circuits provide an output voltage with a plurality of phases according to an input voltage provided by the AC voltage source or the DC voltage source;
• a voltage adjustment control circuit, coupled to the adjustment circuit and providing a plurality of pulse width modulation signals to a plurality of pulse width modulation signal input terminals of the plurality of voltage conversion circuits to control voltage conversion of the plurality of voltage conversion circuits;
• a control circuit, controlling a phase number of the output voltage;
• and
• a driver circuit, coupled to the control circuit and a plurality of enable control terminals of at least part of the plurality of voltage conversion circuits, wherein the control circuit controls the power supply device to enter a throttling mode before the power supply device switches from the AC mode to the DC mode, and the control circuit reduces a system wattage of the power supply device to a preset wattage in the throttling mode, and controls the driver circuit to disable part of the plurality of voltage conversion circuits to reduce the phase number of the output voltage, wherein the preset wattage is lower than the system wattage of the power supply device in the AC mode and in the DC mode.