| 摘要 |
PURPOSE:To prevent blowout of a fuse for overcurrent prevention and breakdown of circuit components when a subscriber circuit is in contact with a commercial power line by connecting a diode in parallel with a series circuit comprising an inductor and the fuse in the polarity opposite to the flowing direction of an overcurrent. CONSTITUTION:The anode of a diode Di is connected to a connecting point between the cathode of a DC power supply VBB and a fuse FUSE, and the cathode of the diode Di is connected to a connecting point between a capacitor C and an inductor L being components of an LC filter. That is, the diode Di is connected in parallel with the series circuit comprising the fuse FUSE and the inductor L in the polarity opposite to overcurrent flowing direction. Thus, blowout of the fuse for overcurrent prevention is prevented when the subscriber circuit is in contact with the commercial power line and the breakdown of a circuit component LSi provided to a line card IC is evaded. |
