Patent US3873905A successfully refreshed from Google Patents.
US3873905A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control circuit to provide shunt path for leakage current
Assignee: LTV Aerospace Corp
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Filing: 1974-03-18
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Granted: 1975-03-25
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Expires: 1994-03-18
Abstract
Abstract A control circuit for a switch circuit having a solid state device such as a transistor, an SCR, or triac used as the switching means connected in series with the load, such switching device having a low impedance in its ON state or condition and a high impedance in its OFF state or condition so that it permits flow of leakage current in its OFF condition, the control circuit providing a shunt path for such leakage current to prevent flow of such leakage current through the load when the switch means is in its OFF condition.
Inventors
- 👤 Albert J Marek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:22
CPC Classifications
F; F42; F42C; F42C15/00; F42C15/40; H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/60; H03K17/72; H03K17/73
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
186 words
A control circuit including: switch means providing a switch circuit having a low impedance in a first condition of said switch means and a high impedance in a second condition of said switch means; a load; a control device connected in series between said switch circuit and said load, said control device being rendered conductive when the voltage thereacross exceeds a predetermined value; means for connecting said switch circuit, said control device and said load in series across an electric current input circuit; shunt means connected between said control device and said switch circuit for shunting from the load currents flowing through said switch circuit when said switch means is in said second condition to prevent the voltage across said control device from exceeding said predetermined value; control means operatively associated with said switch means for selectively placing said switch means in said first and second conditions; and, means operatively associated with said control means for rendering said shunt means operative when said switch means is in said first condition and for rendering said shunt means inoperable when said switch means is in said second condition.
Claim 2
Dependent Claim
186 words
A control circuit including: switch means providing a switch circuit having a low impedance in a first condition of said switch means and a high impedance in a second condition of said switch means; a load; a control device connected in series between said switch circuit and said load, said control device being rendered conductive when the voltage thereacross exceeds a predetermined value; means for connecting said switch circuit, said control device and said load in series across an electric current input circuit; shunt means connected between said control device and said switch circuit for shunting from the load currents flowing through said switch circuit when said switch means is in said second condition to prevent the voltage across said control device from exceeding said predetermined value; control means operatively associated with said switch means for selectively placing said switch means in said first and second conditions; and, means operatively associated with said control means for rendering said shunt means operative when said switch means is in said first condition and for rendering said shunt means inoperable when said switch means is in said second condition.
Claim 3
Dependent Claim
23 words
The control circuit of claim 1 wherein said control device is a diode and said switch means comprises a solid state switch device.
Claim 4
Dependent Claim
67 words
The control circuit of claim 2, wherein said shunt means comprises a transistor having its emitter-collector circuit connected to the common connection of said diode and said switch circuit for conducting current therefrom and wherein said control means comprises means for Rendering said shunt transistor non-conductive when said switch transistor is rendered conductive and for rendering said shunt transistor conductive when said switch transistor is rendered non-conductive.
Claim 5
Dependent Claim
23 words
The control circuit of claim 3 and means for electrically isolating said control means from the said other elements of said control 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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |