| 摘要 |
PURPOSE: To provide the rush current preventing circuit which temporarily makes the power supply line high impedance when the power is tuned on so as to limits the rush current to a capacitor when the input power of the DC power supply circuit is turned on, and returns it to low impedance at the constant time and protects the fuse so that no influence is affected on the operation of the DC power supply circuit. CONSTITUTION: A resistance R1 and the parallel circuit of a P-channel FET 4 are inserted into the power supply circuit between a fuse 2 and a DC power supply circuit 3. A resistance R2 is connected between the gate and the source of the P-channel FET 4. A resistance 3 is grounded from the gate of the P- channel FET 4. Further, a diode D2 and the serial circuit of a transistor Q4 are inserted into between the gate and the source of the P-channel FET 4. A resistance R9 is connected between the base and the emitter of the transistor Q4. A resistance R8 is connected between the base of the transistor Q4 and the drain of the P-channel FET 4. |
