Patent ID: 8178996

Claim:
A power supply unit supplying an object device with a regulated voltage, comprising: a first regulator that generates a first voltage that is stepped-down voltage from a power source; one or more second regulators each generates a second voltage that is stepped-down voltage from the first voltage, and supply the object device with the second voltage as the regulated voltage; a first path through which the first voltage is inputted from the first regulator; a second path that is different from the first path and allows input of an external source; and a first abnormality detecting section that detects abnormal operation of the first regulator, wherein at least one of the second regulators is configured to allow selective connection to either of the first path and the second path, and the second voltage is generated based on the source from the selectively connected path, and the first regulator is configured to stop generating the first voltage when the first abnormality detecting section detects abnormal operation.