Semiconductor switch circuit

A semiconductor switch circuit comprising:

• a bilateral switch includig a couple of 4-terminal PNPN switches connected in inverse parallel, each having a cathode gate and an anode gate;
• a current supplying circuit for supplying a current to the cathode gates of said bilateral switch;
• a current sinking circuit of constant current type;
• and
• a current change-over circuit including current path change-over means for selectively switching a current flowing out from the anode gates of said bilateral switch and a current driving said current supplying circuit, respectively, to said current sinking circuit depending on a potential of said PNPN switches constituting said bilateral switch,
• wherein said change-over circuit includes a PNP transistor having two collectors which are respectively connected to the anode gates of said PNPN switches constituting said bilateral switch.

A semiconductor switch circuit comprising:

• a bilateral switch including a pair of 4-terminal PNPN switches, each having a cathode, a cathode gate, an anode and an anode gate, said 4-terminal PNPN switches being connected together in such an inverse parallel relation that the anode and cathode of one PNPN switch are connected to the cathode and anode of the other PNPN switch, respectively, so as to pass through the bilateral switch a continuous A.C. signal applied across the cathode and anode of each of the PNPN switches;
• a PNP transistor having two collectors connected respectively to the cathode gates of the bilateral switch for feeding a cathode gate driving current to the respective cathode gates;
• a current sinking circuit for taking in a constant current when rendered operative;
• and
• current path change-over means for connecting said current sinking circuit to a selected one of the anode gates of said PNPN switches and to a base of said PNP transistor in response to a potential of one of the cathode and the anode of said one of said PNPN switches.