Configuration for reducing the turn-off time of a thyristor

Abstract

Abstract The present invention is directed to a thyristor having a configuration foreducing turn-off time, said thyristor comprises a main thyristor portion having a main emitter electrode and a control electrode and an auxiliary thyristor portion having an auxiliary emitter electrode and adapted for amplifying the control current, the arrangement includes a voltage source connected to the auxiliary thyristor, and supplying the auxiliary emitter electrode with a current the direction of which is opposite to the direction of the control current. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is in the field of discrete semiconductor devices and is particularly directed to discrete thyristors. 2. Description of the Prior Art The "turn-off time" of a thyristor is the time between the zero passage of a load current and the moment when the thyristor has regained its blocking capability. It is known that the turn-off time of a thyristor can be decreased considerably by provision of recombination centers. However, excessive doping to provide the recombination centers results in considerable increase in power dissipation in the forward direction. It is also known that the turn-off time of a thyristor can be reduced by supplying the control electrode with a current opposite in direction to the control current, thereby upon recovery of the positive potential, causing part of the charge carriers stored in the semiconductor body to be drawn off and thus made unavailable for effecting an undesirable firing. However, the known techniques for reducing turn-off time of a thyristor require a considerable number of electronic components because both control impluses of one polarity and impulses of the opposite polarity must be produced by means of one and the same impulse source. SUMMARY OF THE INVENTION The present invention comprises a thyristor having a reduced turn-off time comprising a main thyristor having a main emitter electrode and a control electrode and an auxiliary thyristor, said auxiliary thyristor being adapted to amplify a control current, said auxiliary thyristor having an auxiliary emitter electrode, a voltage source electrically connected to the auxiliary thyristor to supply through said auxiliary emitter of said auxiliary thyristor a current opposite in direction to the control current.

Inventors

• 👤 Peter Voss

Bibliographic Details