POWER SUPPLY PROTECTION DEVICE, POWER SUPPLY DEVICE, AND SWITCH FAULT DIAGNOSIS METHOD

摘要

A power supply protective device, (1) when obtaining an open voltage in a case where a second switch is brought into a closed state and a first switch is brought into an open state during discharging of a power supply, and obtaining a close voltage in a case where the second switch is brought into the closed state and the first switch is brought into the closed state during discharging of the power supply, diagnoses the first switch as having a failure or not on the basis of the open voltage and the close voltage, and (2) when executing first instruction processing of giving a close instruction to the first switch and the second switch, if a voltage difference between a first voltage and a second voltage detected by a voltage detection unit during execution of the first instruction processing is less than a first threshold voltage, determines that the first switch has no open failure, and/or when a third voltage detected by the voltage detection unit during execution of the first instruction processing is not less than a second threshold voltage, determines that the second switch has no open failure.