摘要 |
In an electric supply device of the present invention, since a semiconductor element T1 is interrupted before a drain voltage V1 of the semiconductor element T1 is lower than an in-phase input minimum voltage, a load circuit can be assuredly protected. Further, assuming that a first decided voltage is L-V1 and a second decided voltage V3, when the voltage V1 becomes "V1 < L-V1", a retry operation is carried out. When the number of times of "V1 < L-V1" reaches N1 times, or when the number of times of "L-V < V1 < V3" reaches N2 times, an interrupted state of the semiconductor element T1 is held to protect the load circuit. Further, when the voltage V1 suddenly drops due to an imperfect contact of a connector 11, a minimum value of the voltage V1 is not a stable value and the interrupted state of the semiconductor T1 is not held. |