Patent attributes
A power supply device includes: a main power supply configured to feed power to a load with constant-voltage output using an external power supply; an auxiliary power supply configured to feed power to the load using an internal power storage unit; a constant-current/constant-voltage switching power supply configured to feed a part of current flowing through the load by which part the current exceeds an upper limit value of output current of the main power supply instructed by a current upper-limit instruction unit, with the constant-current output from the auxiliary power supply; and an output switching unit switching the constant-current/constant-voltage switching power supply from the constant-current output to the constant-voltage output when a power cut monitoring unit determines stop of power supply from the external power supply.
