FAULT DIAGNOSIS CIRCUIT AND FAULT DIAGNOSIS METHOD

摘要

Provided is a fault diagnosis circuit for diagnosing an open-circuit fault in a reverse connection protection transistor, the fault diagnosis circuit being provided with: a power feed part including a switching transistor placed in an on state or an off state in response to a control signal applied to a control terminal, the switching transistor being electrically connected to each of a power source and a reverse connection protection transistor, and electrical power being fed from the power source to the reverse connection protection transistor when the switching transistor is in the on state; a power feed control part for outputting a control signal to the switching transistor and thereby controlling power feeding and stopping of power feeding to the reverse connection protection transistor; and a diagnosis part for diagnosing an open-circuit fault in the reverse connection protection transistor on the basis of the output state of the control signal and the result of detecting a voltage between the switching transistor and the reverse connection protection transistor.