Power supply device capable of supplying large amount of power necessary for entire system operation

A power supply device, comprising:

• a first power-supply unit configured to receive an input external power and to output a first power supplying a predetermined constant voltage to a load;
• a second power-supply unit including a storage device to accumulate charge and configured to output a second power from the storage device to the load in parallel with the first power being supplied from the first power-supply unit;
• and
• a controller configured to output a control signal to prevent the second power-supply unit from supplying power in case of a current increase due to a dynamic load change, and to cause the first power-supply unit to supply power for the dynamic current increase,
• wherein the first power-supply unit supplies power having a current value smaller than a predetermined maximum current of the first power-supply unit,
• wherein the second power-supply unit supplies power for a shortfall current exceeding the predetermined maximum current of the first power-supply unit, and
• wherein the second power-supply unit includes a direct-to-direct-current regulator to output a static load current in response to the control signal.

A method for controlling a power supply device, the method comprising:

• inputting an external power to a first power-supply unit;
• outputting a first power supplying a predetermined constant voltage to a load;
• inputting the external power to a storage device provided in a second power-supply unit to accumulate charge;
• outputting a second power from the storage device to the load in parallel with the first power being supplied from the first power-supply unit;
• outputting a control signal to prevent the second power-supply unit from supplying power in case of a current increase due to a dynamic load change;
• and
• causing the first power to supply power for the dynamic current increase,
• wherein power having a current value smaller than a predetermined maximum current of the first power-supply unit is supplied by the first power-supply unit,
• wherein power for shortfall current exceeding the predetermined maximum current of the first power-supply unit is supplied by the second power-supply unit, and
• wherein a static load current is output to the load from a direct-to-direct-current regulator provided in the second power-supply unit in response to the control signal.