Patent ID: 7974059
Filing Date: 2011-07-05
Classification: H02H

Abstract:
1. A power supply apparatus comprising: a power supply circuit that supplies DC voltage to a load; a current limiting unit that is connected in series between a power source and the power supply circuit, and limits output current flowing from the power source to the power supply circuit; a first switch circuit that is connected in series between the power source and the current limiting unit; a second switch circuit that is connected in parallel with the current limiting unit; a resistor that is connected in series between the power source and the first switch circuit; an abnormal current detection unit that is connected in parallel with the resistor, detects the output current using the resistor, and determines whether or not the output current is abnormal; and a control unit that turns on the first switch circuit so as to cause the abnormal current detection unit to determine whether or not the output current is abnormal if the first switch circuit and the second switch circuit are off, wherein the control unit turns on the second switch circuit if the abnormal current detection unit determines that the output current is not abnormal after the first switch circuit is turned on, the control unit turns off the first switch circuit without turning on the second switch circuit if the abnormal current detection unit determines that the output current is abnormal after the first switch circuit is turned on, and the control unit turns off the first switch circuit if the first switch circuit and the second switch circuit are on and the abnormal current detection unit determines that the output current is abnormal.