| 摘要 |
1,195,998. Thyristor circuits. ALLM€NNA SVENSKA ELEKTRISKA A.B. 30 Oct., 1967 [31 Oct., 1966], No. 49159/67. Heading H3T. [Also in Division H1] Controlled rectifiers (exemplified by fourlayer structures) are designed to handle very high power in the period immediately following ignition by ensuring that the distribution of gate current is widespread and uniform. To do this, both emitter and gate electrodes are provided on the emitter region but are separated by a high-resistance zone of uniform properties. (In the structure shown, high conductivity surface material is removed from the emitter region to leave a high-resistance zone at the bottom of a groove 8.) In variants several highresistance zones may be formed to separate parts of the emitter region which are each provided with a gate or emitter electrode. The gates and emitter are respectively strapped together, either directly or through current dividing impedances. To obtain the desired characteristics a high firing current is needed. This is provided by auxiliary thyristor 21 which may be formed in the same semi-conductor body as the main rectifier. When the auxiliary thyristor is fired by the closure of switch 22, the voltage drop across impedance 20 produces the necessary firing current in the main rectifier. (For structural detail, see Division H1.) |
