US3902079A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switching circuit having multiple operating modes
Assignee: RCA Corp
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Filing: 1974-01-21
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Granted: 1975-08-26
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Expires: 1994-01-21
Abstract
Abstract Complementary transistors, each connected at its base to an input terminal and the collector of the other and one connected at its emitter to an operating voltage source. The other emitter is connected to ground through a controllable impedance and its value controls the circuit operation. It determines whether a path between one of the input terminals and ground will be open and permit the circuit to latch or will close, and if closed, whether the additional path will cause the circuit to remain latched and limit to a given maximum value the load current or will cause the circuit to unlatch.
Inventors
- 👤 Adel Abdel Aziz Ahmed
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:10
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/60; H03K17/602; H03K17/72
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
197 words
A switching circuit having multiple operating modes comprising: first and second circuit points for receiving a signal thereacross to be switched; a third circuit point; switch means connected between said first and third circuit points, said switch means having a trigger electrode responsive to a trigger signal for placing said switch means in a conductive state and having also a regenerative feedback path for maintaining said switch means in said conductive state; first variable impedance means having a controllable current path connected between a point in said regenerative feedback path and said second circuit point, said first variable impedance means having a control electrode connected to said third circuit point for controlling the impedance of said current path: second variable impedance means having a conduction path connected between said second and third circuit points and a control electrode for controlling the conduction thereof; a first circuit control terminal connected to said control electrode of said second variable impedance means for receiving a circuit operating mode control signal; and a second circuit control terminal connected to said trigger electrode of said switch means for initially receiving said trigger signal and applying said trigger signal to said trigger electrode.
Claim 2
Dependent Claim
197 words
A switching circuit having multiple operating modes comprising: first and second circuit points for receiving a signal thereacross to be switched; a third circuit point; switch means connected between said first and third circuit points, said switch means having a trigger electrode responsive to a trigger signal for placing said switch means in a conductive state and having also a regenerative feedback path for maintaining said switch means in said conductive state; first variable impedance means having a controllable current path connected between a point in said regenerative feedback path and said second circuit point, said first variable impedance means having a control electrode connected to said third circuit point for controlling the impedance of said current path: second variable impedance means having a conduction path connected between said second and third circuit points and a control electrode for controlling the conduction thereof; a first circuit control terminal connected to said control electrode of said second variable impedance means for receiving a circuit operating mode control signal; and a second circuit control terminal connected to said trigger electrode of said switch means for initially receiving said trigger signal and applying said trigger signal to said trigger electrode.
Claim 3
Dependent Claim
115 words
The switching circuit recited in claim 1 wherein said switch means comprises: first and second complementary transistors, each having base, emitter and collector electrodes, the collector electrode of each being connected to the base electrode of the other, the emitter electrode of the second transistor being connected to said first circuit point, the emitter electrode of the first transistor being connected to said third circuit point, said controllable current path of said first variable impedance means being connected between said second circuit point and said base electrode of said first transistor; and wherein said second circuit control terminal is connected to a selected one of the base electrodes of said first and second complementary transistors.
Claim 4
Dependent Claim
71 words
The switching circuit recited in claim 2 wherein said first variable impedance means comprises: a third transistor having base, emitter and collector electrodes connected, respectively, to said third circuit point, said second circuit point and said base electrode of said first transistor, said third transistor being of the same conductivity type as said first transistor and having an effective current gain of a value greater than that of said second transistor.
Claim 5
Dependent Claim
40 words
The switching circuit recited in claim 3 wherein said second variable impedance means comprises a fourth transistor having base, emitter and collector electrodes connected, respectively, to said first circuit control terminal, said second circuit point and said third circuit point.
Claim 6
Dependent Claim
40 words
The switching circuit recited in claim 3 wherein said second variable impedance means comprises: a fourth transistor having base, emitter and collector electrodes connected, respectively, to said second circuit point, said first circuit control terminal and said third circuit point.
Claim 7
Dependent Claim
48 words
The switching circuit recited in claim 3 wherein said second variable impedance circuit means comprises: a current mirror having an input terminal connected to said first circuit control terminal, an output terminal connected to said third circuit point and a reference terminal connected to said second circuit point.
Claim 8
Dependent Claim
84 words
The switching circuit recited in claim 6 wherein said current mirror comprises: a fourth transistor having base, emitter and collector electrodes, the collector and emitter electrodes being connected, respectively, to said third circuit point and to said second circuit point, said base electrode thereof being connected to said first circuit control terminal; and a diode connected between said base and said emitter electrodes of said fourth transistor, said diode being poled in a sense to effectively reduce the current gain of said fourth transistor.
Claim 9
Dependent Claim
46 words
The combination recited in claim 3 further comprising at least one diode connected across the base-to-emitter electrodes of a selected one of said second and third transistors for causing the effective current gain of the third transistor to be greater than that of the second transistor.
Claim 10
Dependent Claim
41 words
The combination recited in claim 3 further comprising a separate diode connected across the base and emitter electrodes of each of said second and third transistors for controlling the ratio of the effective current gains of said second and third transistors.
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) | 1978-08-25 | 1979-02-24 | 1979-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-25 | 1983-02-24 | 1983-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-25 | 1987-02-24 | 1987-08-26 | $7700.00 | Window Closed / Lapsed |