| 摘要 |
A semiconductor switching network is disclosed in which complementary bipolar transistors are employed as "floating" crosspoints. Each crosspoint consists of a pair of complementary bipolar transistors with each transistor being connected in series with one of the leads of the communication pair. Each one of the complementary bipolar transistors is, in turn, surrounded by a "protective control shell" of diodes and transistors which provides the crosspoint with overvoltage and reverse voltage protection and secures crosspoint turn-off. Additionally, the protective control shell contains a self-bias arrangement to eliminate the need for external power supplies to operate the crosspoint as well as an optoisolator control circuit to eliminate direct connections to external control circuits. Thus, the disclosed "protective control shell" converts the complementary bipolar transistors into a "floating" crosspoint - powered solely from the communication leads with no direct connection to any external power supply or control circuit, which crosspoint is insensitive to both the polarity and the magnitude of the applied voltage and current. |
