US3766409A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ac power control apparatus with improved switch driver means
Assignee: Westinghouse Electric Corp
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Filing: 1971-08-04
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Granted: 1973-10-16
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Expires: 1991-08-04
Abstract
Abstract AC power control apparatus with reduced power dissipation is provided wherein a three terminal semiconductor switch, such as thyristor, has a gate driver circuit that includes a resistive impedance and a semiconductor device having a P-N junction connected in parallel with the resistive impedance. The semiconductor switch requires less gate current to initiate switching with higher temperature. The P-N junction exhibits a voltage drop thereacross that is inversely proportional to temperature so that a current through said resistive impedance is decreased with increased temperature.
Inventors
- 👤 K Shuey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:36
CPC Classifications
G; G05; G05F; G05F1/00; G05F1/10; G05F1/12; G05F1/40; G05F1/44; G05F1/45; G05F1/452; G05F1/455; H; H02; H02M; H02M1/00; H02M1/08; H02M1/088; H02M1/092; H02M5/00; H02M5/02; H02M5/04; H02M5/22; H02M5/25; H02M5/257; H02M5/2573
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
239 words
Electronic apparatus comprising in combination: a three terminal semiconductor switch having a pair of main terminals for connection in a circuit to be controlled and a third terminal to which signals are applied to initiate switching of said switch, said switch characterized by requiring, for given load circuit conditions, a minimum current at said third terminal to initiate switching that is inversely proportional to the temperature of said switch; a resistive impedance connected to said third terminal; a second semiconductor device having a P-N junction connected in parallel with said resistive impedance and in series with said third terminal, said P-N junction being characterized by a voltage drop thereacross that is inversely proportional to the temperature of said device; said switch and said device being disposed in thermal proximity to be at approximately the same temperature during operation; said resistive impedance being characterized by a voltage drop thereacross that is less thermally sensitive than the voltage drop across said P-N junction of said device to provide a current to said third terminal that is decreased with increased temperature to result in minimized power dissipation; and means, including an amplifier, for applying electrical current continuously to said parallel combination even when said switch is in a state of conduction that could be self-sustained, said amplifier being coupled with said second semiconductor device and responsive thereto to limit said current to a greater extent as temperature of said second device increases.
Claim 2
Dependent Claim
239 words
Electronic apparatus comprising in combination: a three terminal semiconductor switch having a pair of main terminals for connection in a circuit to be controlled and a third terminal to which signals are applied to initiate switching of said switch, said switch characterized by requiring, for given load circuit conditions, a minimum current at said third terminal to initiate switching that is inversely proportional to the temperature of said switch; a resistive impedance connected to said third terminal; a second semiconductor device having a P-N junction connected in parallel with said resistive impedance and in series with said third terminal, said P-N junction being characterized by a voltage drop thereacross that is inversely proportional to the temperature of said device; said switch and said device being disposed in thermal proximity to be at approximately the same temperature during operation; said resistive impedance being characterized by a voltage drop thereacross that is less thermally sensitive than the voltage drop across said P-N junction of said device to provide a current to said third terminal that is decreased with increased temperature to result in minimized power dissipation; and means, including an amplifier, for applying electrical current continuously to said parallel combination even when said switch is in a state of conduction that could be self-sustained, said amplifier being coupled with said second semiconductor device and responsive thereto to limit said current to a greater extent as temperature of said second device increases.
Claim 3
Dependent Claim
30 words
The subject matter of claim 1 wherein: said three terminal semiconductor switch is a thyristor; said second semiconductor device is a transistor; and said amplifier comprises at least one transistor.
Claim 4
Dependent Claim
29 words
The subject matter of claim 2, wherein: said means for applying electrical current comprises an alternating voltage supply and means for converting said alternating voltage to a direct voltage.
Claim 5
Dependent Claim
181 words
Electronic apparatus comprising in combination: an alternating voltage source connected across a load and switch means to control the application of said alternating voltage to said load; said switch means comprising a three terminal semiconductor device having a pair of load terminals connected in a circuit path between said source and said load and a third terminal connected to drive circuit means; said driver circuit means comprising a resistive impedance connected to said third terminal and means exhibiting a voltage drop that is inversely proportional to temperature and more temperature sensitive than said resistive impedance, said latter means connected in parallel with said resistive impedance; and means, including an amplifier, to supply continuous electrical current to said driver circuit means regardless of the conductive condition of said switch means while current to said third terminal is reduced as the voltage drop of said means exhibiting a voltage drop decreases with higher temperature, said amplifier being coupled to said means exhibiting a voltage drop and responsive thereto to limit said current to a greater extent as the temperature of said means increases.
Claim 6
Dependent Claim
181 words
Electronic apparatus comprising in combination: an alternating voltage source connected across a load and switch means to control the application of said alternating voltage to said load; said switch means comprising a three terminal semiconductor device having a pair of load terminals connected in a circuit path between said source and said load and a third terminal connected to drive circuit means; said driver circuit means comprising a resistive impedance connected to said third terminal and means exhibiting a voltage drop that is inversely proportional to temperature and more temperature sensitive than said resistive impedance, said latter means connected in parallel with said resistive impedance; and means, including an amplifier, to supply continuous electrical current to said driver circuit means regardless of the conductive condition of said switch means while current to said third terminal is reduced as the voltage drop of said means exhibiting a voltage drop decreases with higher temperature, said amplifier being coupled to said means exhibiting a voltage drop and responsive thereto to limit said current to a greater extent as the temperature of said means increases.
Claim 7
Dependent Claim
60 words
The subject matter of claim 10, wherein: said switch means further comprises a second thyristor having terminals like those of said first thyristor and connected with said first thyristor in an inverse parallel configuration by said pair of load terminals of said thyristors, and a driver circuit as described is connected to said third terminal of each of said thyristors.
Claim 8
Dependent Claim
117 words
The subject matter of claim 5 wherein said means to supply continuous electrical current comprises: an AC to DC converter means having an AC input from said alternating voltage source and an isolated DC output connected to each of said driver Circuits and a third isolated DC output and a DC to DC converter means powered by said third isolated output of said AC to DC converter and having an isolated DC output connected to each of said driver circuits and supplying a continuous current thereto regardless of the conductive condition of said thyristors; said DC to DC converter means having a control signal input means to initiate the placing of said thyristors in the conductive state.
Claim 9
Dependent Claim
44 words
The subject matter of claim 6, wherein: said AC to DC converter means comprises a transformer with a primary winding connected to said alternating voltage source and three isolated secondary windings, each with full wave rectifier means for each of said isolated DC outputs.
Claim 10
Dependent Claim
34 words
The subject matter of claim 6, wherein: said DC to DC converter means comprises an additional transformer connected as a free running oscillator with two isolated secondary windings for said two driver circuit means.
Claim 11
Dependent Claim
39 words
The subject matter of claim 6, wherein: said DC to DC converter means comprises a pair of light emitting diodes each in optical coupled relation with a photosensitive semiconductor device connected in circuit with one of said drive circuits.
Claim 12
Dependent Claim
16 words
The subject matter of claim 4 wherein: said three terminal semiconductor device is a first thyristor.
References Cited (Backward Citations)
US3278823A
Cited
US3334244A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-15 | 1977-04-16 | 1977-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-15 | 1981-04-16 | 1981-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-15 | 1985-04-16 | 1985-10-16 | $7700.00 | Window Closed / Lapsed |