PURPOSE: To obtain a preferably dv/dt characteristics in a semiconductor bidirectional switch by employing an improved circuit for special critical off voltage rise ratio characteristics integrated by a P-N junction isolating process.
CONSTITUTION: PNPN type elements 5, 6, emitter vs. collector symmetrical PNP transistor 9, NPN type transistors 10, 11, diodes 12, 13 are formed on an N type semiconductor substrate 19. Then, bypass gate and cathode resistors 7 and 8 are formed in a P type gate regions of the elements 5, 6. When positive and negative polarity dv/dt displacement voltages are applied to terminals 1 and 2 respectively, a displacement current will flow two paths of the anode and substrates 19 of the PNPN element 5 through a capacity between the emitter and the base as well as between the base and the collector of the diode 13 and the transistor 9 to the base 17 of the transistor 10, and the dv/dt displacement current is flowed through the transistor 10 by improving the dv/dt characteristics.
HAGIMURA KAZUO
KATOU KOUTAROU
NIPPON TELEGRAPH & TELEPHONE