| 摘要 |
PURPOSE:To obtain the photodriven type thyristor having a simple-structured sheath by a method wherein the thyristor is formed in such manner that it has a selfprotecting function in itself by means of applying and conducting a current to a gate through the intermediary of an overvoltage protective element when forward direction overvoltage is applied. CONSTITUTION:The photodriven thyristor consists of a photoauxiliary thyristor ATHY and a main thyristor MTHY. A p-emitter layer nE, an anode electrode 15 and a cathode electrode 14 are formed on a semiconductor substrate 10. Then, an optical fiber 3 for the turn-on of light and a cathode electrode 140 are provided on the ATHY and the circuit, consisting of a diode 200, a Zener diode 201 and an overvoltage protective element 202, is connected to a gate electrode 141. When forward direction overvoltage is applied, the overvoltage protective element works, a current is applied to the pB layer through the electrode 141 and the thyristor is turned to be conductive, thereby enabling to prevent the breakdown due to an excess current. |
