(19)
(11)EP 0 262 958 A3

(12)EUROPEAN PATENT APPLICATION

(88)Date of publication A3:
06.12.1989 Bulletin 1989/49

(43)Date of publication A2:
06.04.1988 Bulletin 1988/14

(21)Application number: 87308676.3

(22)Date of filing:  30.09.1987
(51)International Patent Classification (IPC)4H03K 17/73, H01L 29/74
(84)Designated Contracting States:
CH DE LI SE

(30)Priority: 30.09.1986 JP 231769/86
13.01.1987 JP 3941/87
26.02.1987 JP 41315/87
26.02.1987 JP 41359/87

(71)Applicant: KABUSHIKI KAISHA TOSHIBA
Kawasaki-shi, Kanagawa-ken 210 (JP)

(72)Inventors:
  • Ogura, Tsuneo c/o Patent Division
    Minato-ku Tokyo 105 (JP)
  • Takigami, Katsuhiko c/o Patent Division
    Minato-ku Tokyo 105 (JP)
  • Nakagawa, Akio c/o Patent Division
    Minato-ku Tokyo 105 (JP)
  • Domon, Tomokazu c/o Patent Division
    Minato-ku Tokyo 105 (JP)

(74)Representative: Freed, Arthur Woolf et al
MARKS & CLERK, 57-60 Lincoln's Inn Fields
London WC2A 3LS
London WC2A 3LS (GB)


(56)References cited: : 
  
      


    (54)Thyristor drive system


    (57) A gate turn-off thyristor drive system with low power loss when it is in the turn-off mode, is dis­closed. A first turn-off pulse of a predetermined amplitude is applied to a first gate electrode (16). A second turn-off pulse is applied to a second gate electrode (18). An amplitude of the second turn-off pulse is smaller in absolute value than that of the first turn-off pulse. The fall time of the anode current at the time of turn-off is reduced, and the initial value of the tail current of the anode current is reduced. The power loss as the product of the anode voltage and the anode current is reduced.







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