| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor switching apparatus to respond at high speed to an unusual current when occurring an incomplete short-circuit with detecting an over current in spite of an occurrence of inrush current. SOLUTION: In the apparatus, varying levels of source voltages between a main field effect transistor(FET) of a multi-source FET and a reference FET are compared. When a source voltage of the main FET is exceeding that of the reference FET, a driving voltage is applied to a gate of the multi-source FET, when not exceeding, the driving voltage is cut off to the gate. Furthermore, a circuit to control a current of the reference FET to prevent the source voltage of the reference FET from exceeding that of the main FET is equipped between the source of the reference FET and a ground. Thus, the unusual current fed to the main FET is detected, when occurring the unusual current, the main FET is on/off-controlled to generate a current vibration that drives the main FET into cutoff.
|
