US3812382A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Synchronous switching circuit
Assignee: Grigsby Barton Inc
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Filing: 1972-08-25
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Granted: 1974-05-21
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Expires: 1992-08-25
Abstract
Abstract A switching circuit for controlling the application of an a.c. source to a load employs a detector for selectively triggering a control thyristor at a zero-voltage crossing of the source and means for latching the control thyristor during succeeding cycles of the a.c. source. The control thyristor is employed to latch a switching thyristor which, in turn, applies the power from the a.c. source to the load.
Inventors
- 👤 J Pascente
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:21
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/13; H03K17/136
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
231 words
A switching circuit for controlling the application of an a.c. source to a load, comprising switching thyristor means having a pair of load terminals and a control terminal and having a bidirectional switching characteristic, means coupled to said load terminals for connecting the a.c. source to the load, control thyristor means having a pair of load terminals and a control terminal, detector means for providing a signal indicative of a zero-voltage crossing of said a.c. course, means for supplying current to the load terminals of said control thyristor means, circuit means coupled to the control terminal of said control thyristor means and responsive to said signal for triggering said control thyristor means for supplying latching current thereto during succeeding cycles of said a.c. source once said control thyristor means becomes conductive, and switching means responsive to said control thyristor means for selectively coupling, and uncoupling, the control terminal of said switching thyristor means to, and from, one of said load terminals thereof in accordance with the state of said control thyristor means, said switching means having a pair of control terminals and a pair of controlled terminals, said pair of control terminals being connected in series circuit relation to the load terminals of said control thyristor means and said pair of controlled terminals being serially connected between the control terminal of said switching thyristor means and said one load terminal thereof.
Claim 2
Dependent Claim
231 words
A switching circuit for controlling the application of an a.c. source to a load, comprising switching thyristor means having a pair of load terminals and a control terminal and having a bidirectional switching characteristic, means coupled to said load terminals for connecting the a.c. source to the load, control thyristor means having a pair of load terminals and a control terminal, detector means for providing a signal indicative of a zero-voltage crossing of said a.c. course, means for supplying current to the load terminals of said control thyristor means, circuit means coupled to the control terminal of said control thyristor means and responsive to said signal for triggering said control thyristor means for supplying latching current thereto during succeeding cycles of said a.c. source once said control thyristor means becomes conductive, and switching means responsive to said control thyristor means for selectively coupling, and uncoupling, the control terminal of said switching thyristor means to, and from, one of said load terminals thereof in accordance with the state of said control thyristor means, said switching means having a pair of control terminals and a pair of controlled terminals, said pair of control terminals being connected in series circuit relation to the load terminals of said control thyristor means and said pair of controlled terminals being serially connected between the control terminal of said switching thyristor means and said one load terminal thereof.
Claim 3
Dependent Claim
123 words
The circuit of claim 1 comprising an additional switching thyristor means, control thyristor means, and means for connecting an a.c. source to a load through the load terminals of said additional switching thyristor means, said circuit means being coupled to the control terminal of said additional control thyristor means and responsive to said signal for triggering the same and supplying latching current thereto during succeeding cycles of the a.c. source once said additional control thyristor means becomes conductive and additional switching means responsive to said additional control thyristor means for selectively coupling, and uncoupling, the control terminal of said additional switching thyristor means to, and from, one of said load terminals thereof in accordance with the state of said additional control thyristor means.
Claim 4
Dependent Claim
38 words
The circuit of claim 2 comprising respective control means in series with the load terminals of each of said control thyristor means for selectively enabling each of the same to become conductive in response to said triggering signal.
Claim 5
Dependent Claim
44 words
The circuit of claim 1 wherein said switching means comprises a relay being actuable by the current through the load terminals of said control thyristor means and having contacts connected between the control terminal and said one load terminal of said switching thyristor means.
Claim 6
Dependent Claim
32 words
The circuit of claim 1 comprising control means in series with the load terminals of said control thyristor means for enabling the same to become conductive in response to said triggering signal.
Claim 7
Dependent Claim
37 words
The circuit of claim 1 comprising circuit isolating means connected between said detector means and said circuit means to permit operation of the latter at a low d.c. voltage relative to the voltage of said a.c. source.
Claim 8
Dependent Claim
14 words
The circuit of claim 6 wherein said circuit isolating means comprises an opto-electronic relay.
Claim 9
Dependent Claim
235 words
A circuit for controlling the application of an a.c. source to a load, comprising: a. a power switching circuit including a switching thyristor having a pair of load terminals and a control terminal and having a bidirectional switching characteristic, means coupled to said load terminals for connecting the a.c. source to the load, a control thyristor circuit comprising a control thyristor having a pair of load terminals and a control terminal and circuit means for coupling the pair of load terminals of said control thyristor to a source of d.c. voltage, said circuit means including a relay having the electromagnetic coil thereof connected in series circuit relation to said control thyristor load terminals and said d.c. source, and the controlled contacts of said relay connected between the control terminal and one of the load terminals of said switching thyristor, b. a detector circuit comprising a rectifier circuit for providing a d.c. voltage from said a.c. source, and a transistor circuit coupled to said rectifier circuit and including biasing resistances for biasing the transistor to provide an output signal indicative of a zero-voltage crossing of said a.c. source, and c. means responsive to said detector output signal for applying a trigger voltage to the control terminal of said control thyristor at said zero-voltage crossing of the a.c. source, while electrically isolating the d.c. voltage levels of said control thyristor circuit from those of said detector circuit.
Claim 10
Dependent Claim
235 words
A circuit for controlling the application of an a.c. source to a load, comprising: a. a power switching circuit including a switching thyristor having a pair of load terminals and a control terminal and having a bidirectional switching characteristic, means coupled to said load terminals for connecting the a.c. source to the load, a control thyristor circuit comprising a control thyristor having a pair of load terminals and a control terminal and circuit means for coupling the pair of load terminals of said control thyristor to a source of d.c. voltage, said circuit means including a relay having the electromagnetic coil thereof connected in series circuit relation to said control thyristor load terminals and said d.c. source, and the controlled contacts of said relay connected between the control terminal and one of the load terminals of said switching thyristor, b. a detector circuit comprising a rectifier circuit for providing a d.c. voltage from said a.c. source, and a transistor circuit coupled to said rectifier circuit and including biasing resistances for biasing the transistor to provide an output signal indicative of a zero-voltage crossing of said a.c. source, and c. means responsive to said detector output signal for applying a trigger voltage to the control terminal of said control thyristor at said zero-voltage crossing of the a.c. source, while electrically isolating the d.c. voltage levels of said control thyristor circuit from those of said detector circuit.
Claim 11
Dependent Claim
35 words
The circuit of claim 8 wherein said means responsive to said detector output signal includes an amplifier circuit energized by a source of d.c. voltage during operation of said circuit for providing said trigger voltage.
Claim 12
Dependent Claim
58 words
The circuit of claim 9 for controlling the application of one or more a.c. sources to a plurality of loads, wherein said circuit comprises a plurality of said power switching circuits and wherein said amplifier circuit is coupled to the control terminal of each control thyristor of the respective power switching circuits to provide said trigger voltage thereto.
Claim 13
Dependent Claim
39 words
The circuit of claim 10 comprising control means in series with the load terminals of each control thyristor of the respective power switching circuits for separately enabling the control thyristors to become conductive in response to said trigger voltage.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |