Vehicle power supply device and door latch device

A vehicle power supply device comprising:

• a backup power supply to which power is supplied from a battery mounted in a vehicle;
• a boost unit that boosts a voltage of the backup power supply to a predetermined boost voltage;
• a motor drive unit that is connected to the battery and the boost unit and is capable of driving an electric motor by being supplied with power from one of the battery and the boost unit;
• a first switching unit that conducts or interrupts power supply between the battery and the motor drive unit;
• a control unit that controls the first switching unit;
• and
• a second switching unit that is provided between the boost unit and the first switching unit, turns off the first switching unit when the backup power supply is sufficiently charged so that a voltage output from the boost unit becomes equal to or higher than the predetermined boost voltage, and turns on the first switching unit when a charge amount of the backup power supply is not enough such that a voltage output from the boost unit is not boosted to the predetermined boost voltage.