US4663547A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite circuit for power semiconductor switching
Assignee: Fairchild Semiconductor Corp
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Filing: 1981-04-24
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Granted: 1987-05-05
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Expires: 2001-04-24
Abstract
Abstract A solid state composite control circuit includes a normally-off gating device connected in series with a normally-on high voltage semiconductor device so that the combination operates as a normally-off high power semiconductor device. The control device is a low voltage semiconductor device, which can switch rapidly with very low gate turn-off current during turn-off of the composite circuit. In a particular example, a low voltage, normally-off, MOSFET is connected in series with the cathode of a high voltage, normally-on FCT. In another example, a low voltage, normally-off, MOSFET is connected in series with the source of a high voltage, normally-on JFET. The composite circuit has a very high turn-off gain as well as high dv/dt and di/dt capability.
Inventors
- 👤 Bantval J. Baliga
- 👤 Michael S. Adler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:47
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/687; H03K17/6871; H03K17/567
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
151 words
A composite control circuit comprising: a high voltage normally-on field controlled thyristor having an anode, a cathode and a gate, a potential barrier between said anode and said cathode precluding conduction by said field controlled thyristor when said anode is biased positive with respect to said gate; and a low voltage normally-off field effect transistor having a source terminal, a drain terminal and a gate terminal, said cathode of said field controlled thyristor being connected to said drain terminal of said field effect transistor, said gate of said field controlled thyristor being connected to said source terminal of said field effect transistor; said field effect transistor short-circuiting said gate to said cathode so as to remove said potential barrier and permit anode-to-cathode current flow in said thyristor in response to application of a voltage signal to said gate terminal of sufficient amplitude to render conductive said low voltage field effect transistor.
Claim 2
Dependent Claim
151 words
A composite control circuit comprising: a high voltage normally-on field controlled thyristor having an anode, a cathode and a gate, a potential barrier between said anode and said cathode precluding conduction by said field controlled thyristor when said anode is biased positive with respect to said gate; and a low voltage normally-off field effect transistor having a source terminal, a drain terminal and a gate terminal, said cathode of said field controlled thyristor being connected to said drain terminal of said field effect transistor, said gate of said field controlled thyristor being connected to said source terminal of said field effect transistor; said field effect transistor short-circuiting said gate to said cathode so as to remove said potential barrier and permit anode-to-cathode current flow in said thyristor in response to application of a voltage signal to said gate terminal of sufficient amplitude to render conductive said low voltage field effect transistor.
Claim 3
Dependent Claim
143 words
A composite control circuit comprising: a high voltage normally-on field controlled thyristor having an anode, a cathode and a gate, a potential barrier between said anode and said cathode precluding conduction by said field controlled thyristor when said anode is biased positive with respect to said gate; and a low voltage normally-off bipolar transistor having an emitter terminal, a collector terminal and a base terminal; said cathode of said field controlled thyristor being connected to said collector terminal of said bipolar transistor, said gate of said field controlled thyristor being connected to said emitter terminal of said bipolar transistor; said bipolar transistor short-circuiting said gate to said cathode so as to remove said potential barrier and permit anode-to-cathode current flow in said thyristor in response to a current signal applied to said base terminal of sufficient amplitude to render conductive said bipolar transistor.
Claim 4
Dependent Claim
143 words
A composite control circuit comprising: a high voltage normally-on field controlled thyristor having an anode, a cathode and a gate, a potential barrier between said anode and said cathode precluding conduction by said field controlled thyristor when said anode is biased positive with respect to said gate; and a low voltage normally-off bipolar transistor having an emitter terminal, a collector terminal and a base terminal; said cathode of said field controlled thyristor being connected to said collector terminal of said bipolar transistor, said gate of said field controlled thyristor being connected to said emitter terminal of said bipolar transistor; said bipolar transistor short-circuiting said gate to said cathode so as to remove said potential barrier and permit anode-to-cathode current flow in said thyristor in response to a current signal applied to said base terminal of sufficient amplitude to render conductive said bipolar transistor.
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) | 1990-05-04 | 1990-11-03 | 1991-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-04 | 1994-11-03 | 1995-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-04 | 1998-11-03 | 1999-05-05 | $7700.00 | Window Closed / Lapsed |