US3870904A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for controlling a thyristor by direct current logic
Assignee: Mayfran International Inc
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Filing: 1973-05-21
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Granted: 1975-03-11
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Expires: 1993-05-21
Abstract
Abstract There is provided a circuit for gating a thyristor semiconductor device used in switching alternating current. The thyristor has a conductive state when a signal of at least a first voltage is applied to its gate and a non-conductive state when a signal of a voltage below a second voltage is applied to the gate. The circuit includes an integrated circuit logic gate with an output having a low logic state and a high logic state. When in the low state, the thyristor is gated to the non-conductive condition by provision of a voltage drop device between the integrated circuit logic gate and the gate of the thyristor. Also, in the high logic state, there is provided an auxiliary current source to provide the necessary current to gate the thyristor into conduction even though the integrated circuit logic gates does not have sufficient current capacity.
Inventors
- 👤 Delmas A Schock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:30
CPC Classifications
H; H03; H03K; H03K19/00; H03K19/0175; H03K19/017545; H03K17/00; H03K17/51; H03K17/56; H03K17/72; H03K17/725
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
323 words
A direct current circuit for gating a triac used to switch alternating current applied across said triac, said triac having a gate and being in a conductive state when a signal of at least a first voltage and at least a given current is applied to said gate of said triac and a non-conductive condition when a signal of a voltage below a second voltage is applied to said gate, said direct current circuit comprising: a. a logic gate with an output having a low logic state having a first output voltage above said second voltage and insufficient to positively render said triac non-conductive when said logic Gate is shifted to its low logic state and said first output voltage created during the low logic state of said logic gate being less than a third voltage, said logic gate having a high logic state with a second output voltage above said first voltage by at least substantially more than said third voltage to provide a sufficient voltage to render said triac conductive and the output current of said logic gate during said high logic state being less than said given current to provide insufficient current to render said triac conductive; b. circuit means for connecting said logic gate output to said gate of said triac, said circuit means including a voltage drop element connected between said logic gate output and said triac gate and having a maximum voltage drop of approximately said third voltage; and, c. a current source connected to said logic gate output and between said logic gate output and said voltage drop element for providing additional current to said circuit means, said provided current being added to said output current of said logic gate when in said high state to provide a current summation having a value at least as great as said given current to render said triac conductive when said logic gate is in said high logic state.
Claim 2
Dependent Claim
323 words
A direct current circuit for gating a triac used to switch alternating current applied across said triac, said triac having a gate and being in a conductive state when a signal of at least a first voltage and at least a given current is applied to said gate of said triac and a non-conductive condition when a signal of a voltage below a second voltage is applied to said gate, said direct current circuit comprising: a. a logic gate with an output having a low logic state having a first output voltage above said second voltage and insufficient to positively render said triac non-conductive when said logic Gate is shifted to its low logic state and said first output voltage created during the low logic state of said logic gate being less than a third voltage, said logic gate having a high logic state with a second output voltage above said first voltage by at least substantially more than said third voltage to provide a sufficient voltage to render said triac conductive and the output current of said logic gate during said high logic state being less than said given current to provide insufficient current to render said triac conductive; b. circuit means for connecting said logic gate output to said gate of said triac, said circuit means including a voltage drop element connected between said logic gate output and said triac gate and having a maximum voltage drop of approximately said third voltage; and, c. a current source connected to said logic gate output and between said logic gate output and said voltage drop element for providing additional current to said circuit means, said provided current being added to said output current of said logic gate when in said high state to provide a current summation having a value at least as great as said given current to render said triac conductive when said logic gate is in said high logic state.
Claim 3
Dependent Claim
323 words
A direct current circuit for gating a triac used to switch alternating current applied across said triac, said triac having a gate and being in a conductive state when a signal of at least a first voltage and at least a given current is applied to said gate of said triac and a non-conductive condition when a signal of a voltage below a second voltage is applied to said gate, said direct current circuit comprising: a. a logic gate with an output having a low logic state having a first output voltage above said second voltage and insufficient to positively render said triac non-conductive when said logic Gate is shifted to its low logic state and said first output voltage created during the low logic state of said logic gate being less than a third voltage, said logic gate having a high logic state with a second output voltage above said first voltage by at least substantially more than said third voltage to provide a sufficient voltage to render said triac conductive and the output current of said logic gate during said high logic state being less than said given current to provide insufficient current to render said triac conductive; b. circuit means for connecting said logic gate output to said gate of said triac, said circuit means including a voltage drop element connected between said logic gate output and said triac gate and having a maximum voltage drop of approximately said third voltage; and, c. a current source connected to said logic gate output and between said logic gate output and said voltage drop element for providing additional current to said circuit means, said provided current being added to said output current of said logic gate when in said high state to provide a current summation having a value at least as great as said given current to render said triac conductive when said logic gate is in said high logic state.
Claim 4
Dependent Claim
323 words
A direct current circuit for gating a triac used to switch alternating current applied across said triac, said triac having a gate and being in a conductive state when a signal of at least a first voltage and at least a given current is applied to said gate of said triac and a non-conductive condition when a signal of a voltage below a second voltage is applied to said gate, said direct current circuit comprising: a. a logic gate with an output having a low logic state having a first output voltage above said second voltage and insufficient to positively render said triac non-conductive when said logic Gate is shifted to its low logic state and said first output voltage created during the low logic state of said logic gate being less than a third voltage, said logic gate having a high logic state with a second output voltage above said first voltage by at least substantially more than said third voltage to provide a sufficient voltage to render said triac conductive and the output current of said logic gate during said high logic state being less than said given current to provide insufficient current to render said triac conductive; b. circuit means for connecting said logic gate output to said gate of said triac, said circuit means including a voltage drop element connected between said logic gate output and said triac gate and having a maximum voltage drop of approximately said third voltage; and, c. a current source connected to said logic gate output and between said logic gate output and said voltage drop element for providing additional current to said circuit means, said provided current being added to said output current of said logic gate when in said high state to provide a current summation having a value at least as great as said given current to render said triac conductive when said logic gate is in said high logic state.
Claim 5
Dependent Claim
19 words
A direct current circuit as defined in claim 1 wherein said voltage drop element is at least one diode.
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) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |