| 摘要 |
A switching device includes a commanding device (813, Q51) which commands a driving of a load, a driving device (111) which outputs a drive signal in response to a drive command signal from the commanding device (813, Q51) and a first switching device (QA) inserted in a power supply circuit connecting a power supply (101) and the load (102). The first switching device (QA) is adapted to conduct in response to the drive signal and close the power supply circuit. A reference resistor (Rr1, Rr2) generates a reference voltage by receiving a current from the power supply, and a second switching device (QB, QC) is inserted in a shunt circuit connecting the power supply and the reference resistor. The second switching device (QB, QC) is adapted to conduct in response to the drive signal and close the shunt circuit. An abnormality determining device (CMP1, CMP2) determines an abnormality by comparing an output voltage from the first switching device (QA) and the reference voltage. A cutoff latch device 306, Q53) changes the drive command signal outputted to the driving device (111) into a stop command signal in response to an abnormality determination signal of the abnormality determining device (CMP1, CMP2). A monitoring device (811) monitors a state of the load (102) on the basis of a state of the command signal inputted to the driving device (111).
|
