Patent US4491742A successfully refreshed from Google Patents.
US4491742A
Expired / Lapsed
US
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Semiconductor switch device
Assignee: Mitsubishi Electric Corp
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Filing: 1982-10-25
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Granted: 1985-01-01
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Expires: 2002-10-25
Abstract
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.
Inventors
- 👤 Masahiko Akamatsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:58
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/101; H10D84/131; H02; H02M; H02M3/00; H02M3/02; H02M3/04; H02M3/10; H03; H03K; H03K17/00; H03K17/12; H03K17/125; H03K17/51; H03K17/56; H03K17/72; H03K17/73; H10D18/00; H10D18/60; H10D88/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
165 words
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.
Claim 2
Dependent Claim
165 words
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.
Claim 3
Dependent Claim
21 words
A semiconductor switch as in claim 1, including: a capacitive impedance connected between the collector and the base of the transistor.
Claim 4
Dependent Claim
25 words
A semiconductor switch device as in claim 1, including: an external re-applying voltage suppressing means connected between the collector and the emitter of the transistor.
Claim 5
Dependent Claim
39 words
A semiconductor switch device as in claim 3, wherein: the external re-applying voltage suppressing means comprises a diode and a resistor connected in parallel to form a parallel circuit and a capacitor connected in series to the parallel circuit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-01-01 | 1988-07-02 | 1989-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-01 | 1992-07-02 | 1993-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-01 | 1996-07-02 | 1997-01-01 | $7700.00 | Window Closed / Lapsed |