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US 4,491,742 AGranted
Semiconductor switch device
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorMasahiko Akamatsu
Life of this patent
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Abstract
A self-turn-off type semiconductor switch comprising a gate-reverse biasing thyristor and a transistor connected in parallel to each other wherein the load current is shunted to the transistor, thus causing the thyristor to be turned off.
Claims4
A semiconductor switch device comprising:
- a transistor having a base and main electrodes, the main electrodes of the transistor including a collector and an emitter;
- a thyristor having a gate and main electrodes, the electrodes of the thyristor including and an anode and a cathode;
- a power path for carrying current from a source to said anode;
- said main electrodes of said transistor and said main electrodes of said thyristor being connected in parallel in the same direction;
- resistor means connecting the base of the transistor to the gate of the thyristor;
- forward biased voltage means including a first diode means connected to said resistor means for applying to said resistor means a forward biased voltage to turn-on said transistor and said thyristor;
- and
- reversed biased voltage means including a second diode means connected to said resistor mean for applying a reversed biased voltage to turn off said thyristor and said transistor;
- whereby said transistor reduces and absorbs the turn-off switching power of said thyristor.
6 more elements
Dependencies are inferred from the claim text.