| 摘要 |
PURPOSE:To prevent a device against rush current flowing to a load, by providing a means to limit the current when instantaneous breakage is restored. CONSTITUTION:A power voltage 1 is supplied to an instantaneous breakage detection circuit 10a. The voltage VG supplied to a base of a transistor 12 in the instantaneous breakage detection circuit 10a has a time constant determined by a resistance R3 and a capacitor C2 when the power voltage 1 is at the leading edge, and has a time constant determined by a resistance R4 and a capacitor C2 at the trailing edge. The output of the transistor 12 is supplied to the gate of an FET 21 of a rush current regulation circuit 20a. The resistance between the source and drain of the FET 21 is small when the voltage VG is large, while when the voltage VG becomes small, the above resistance becomes large. Immediately after the restoration of instantaneous breakage, the voltage VG is therefore so small that the resistance of FET 21 is large and the rush current can be limited to the minimum. |
