Power supply device for supplying power to a load by combining a secondary battery and a capacitor

A power supply device configured to supply power to a load by combining a secondary battery and a capacitor connected in parallel to the secondary battery, the power supply device comprising:

• an insulation type DC-DC converter including a primary coil and a secondary coil, the primary coil being connected in parallel to the secondary battery, the primary coil being configured to accumulate energy by a current supplied from the secondary battery, the secondary coil being connected in series to the capacitor, the secondary coil being configured such that an induction current flows therein by the accumulated energy from the primary coil;
• wherein a current from the secondary battery is directly supplied to the primary coil and the insulation type DC-DC converter is configured to adjust an output voltage to be output from the secondary coil so that a sum of the output voltage and a voltage of the capacitor becomes equal to a voltage of the secondary battery.