US4037117A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Peak shut-off electronic switch
Assignee: AT&T Inc
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Filing: 1976-03-15
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Granted: 1977-07-19
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Expires: 1996-03-15
Abstract
Abstract A control transistor and a pnpn device are arranged in serial combination with each other, as well as with a source of alternating current and a load. The transistor and pnpn device in combination behave as a two-state semiconductor switch for switching cyclically varying currents and voltages of amplitude greater than the punch-through voltage limit of the transistor. The switch conducts an unrectified, cyclically varying waveform by operation of a diode biasing scheme. Circuitry responsive to voltage peaks of the source causes the transistor to periodically open the circuit for a short duration, thereby discontinuing the transmission of energy to the load within a fraction of a cycle after a discontinuation command signal is received.
Inventors
- 👤 Robert Lawrence Carbrey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:50
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/72; H03K17/725; H04; H04M; H04M19/00; H04M19/02; H04M19/04; H04Q; H04Q11/00; H04Q11/04
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
160 words
A switching circuit for interrupting cyclically varying signals comprising at least one first switching device connected in series with a second switching device each first and second switching device having at least first, second and third terminals, the first terminal of each first switching device connected to the second terminal of the second switching device, each first switching device conducting an electric current in one direction along an internal electrical path between its first and second terminals which electrical conduction is initiated by application of enabling signals to the third terminal and discontinued by application of disabling signals to the third terminal when the electric current flowing through the internal electrical path is below a predetermined level, and a circuit for periodically opening the second switching device during a fraction of a cycle of preselected polarity of the cylically varying signals to ensure discontinuation of the electric current flowing through the first switching device in response to the disabling signals.
Claim 2
Dependent Claim
160 words
A switching circuit for interrupting cyclically varying signals comprising at least one first switching device connected in series with a second switching device each first and second switching device having at least first, second and third terminals, the first terminal of each first switching device connected to the second terminal of the second switching device, each first switching device conducting an electric current in one direction along an internal electrical path between its first and second terminals which electrical conduction is initiated by application of enabling signals to the third terminal and discontinued by application of disabling signals to the third terminal when the electric current flowing through the internal electrical path is below a predetermined level, and a circuit for periodically opening the second switching device during a fraction of a cycle of preselected polarity of the cylically varying signals to ensure discontinuation of the electric current flowing through the first switching device in response to the disabling signals.
Claim 3
Dependent Claim
33 words
A circuit in accordance with claim 1 in which each first switching device comprises a pnpn device having cathode, anode and gate terminals, which terminals respectively comprise the first, second and third terminals.
Claim 4
Dependent Claim
75 words
A switching circuit in accordance with claim 1 in which the cyclically varying signals have such an average voltage level as to be bipolar, the switching circuit further comprising means for shifting the average voltage level of an electrical path comprising the series first and second switching devices so as to convert the cyclically varying bipolar signals into cyclically varying direct current voltages on the electrical path comprising the series first and second switching devices.
Claim 5
Dependent Claim
92 words
A switching circuit in accordance with claim 3 in which the means for shifting the operating voltage level of the electrical path comprising the series first and second switching devices comprises a first diode connected to the second terminal of the first switching device for clipping the voltage on the second terminal thereby preventing the voltage from exceeding a predetermined level, and a second diode connected to the first terminal of the second switching device for clipping the voltage on the first terminal thereby preventing the voltage from exceeding a predetermined level.
Claim 6
Dependent Claim
71 words
A switching circuit in accordance with claim 1 in which the second switching device comprises a first transistor having an internal electrical path between collector and emitter terminals in series with the first switching device and a base terminal for receiving signals from the circuit for periodically opening the second switching device, which emitter, collector and base terminals respectively comprise the first, second and third terminals of the second switching device.
Claim 7
Dependent Claim
103 words
A switching circuit in accordance with claim 1 wherein the circuit for periodically opening the second switching device comprises a third switching device having an internal electrical path between first and second terminals for conducting a direct current, which conduction is controlled by enabling and disabling signals received at a third terminal, which enabling and disabling signals are responsive to periodic peaks of preselected polarity of the cyclically varying signals, and means for delivering signals generated by the controlled conduction through the third switching device to the third terminal of the second switching device thereby periodically opening and closing the second switching device.
Claim 8
Dependent Claim
127 words
A circuit in accordance with claim 6 wherein the third switching device comprises a second transistor having collector, base and emitter terminals, which terminals comprise the first, second and third terminals respectively of the third switching device, and the means for delivering a signal to the third terminal of the second switching device comprising a capacitor, one terminal of which is connected to the collector of the second transistor and the other terminal to the third terminal of the second switching device for delivering a signal on the collector of the second transistor, which signal is responsive to the enabling and disabling signals at the base of the second transistor, to the third terminal of the second switching device for opening and closing the second switching device.
Claim 9
Dependent Claim
130 words
A switching circuit for interrupting cyclically varying signals having such an average voltage level as to be bipolar comprising a first switching device having at least first, second and third terminals for conducting an electrical signal in one direction along an internal electrical path between the first and second terminals, which electrical conduction is initiated by application of enabling signals to the third terminal and discontinued by application of disabling signals when the electric current flowing through the internal electrical path is below a predetermined level, and means for shifting the average voltage level of the electrical path between the first and second terminals so as to convert the cyclically varying bipolar signal into cyclically varying direct current voltage having a waveshape substantially similar to that of the bipolar signal.
Claim 10
Dependent Claim
130 words
A switching circuit for interrupting cyclically varying signals having such an average voltage level as to be bipolar comprising a first switching device having at least first, second and third terminals for conducting an electrical signal in one direction along an internal electrical path between the first and second terminals, which electrical conduction is initiated by application of enabling signals to the third terminal and discontinued by application of disabling signals when the electric current flowing through the internal electrical path is below a predetermined level, and means for shifting the average voltage level of the electrical path between the first and second terminals so as to convert the cyclically varying bipolar signal into cyclically varying direct current voltage having a waveshape substantially similar to that of the bipolar signal.
Claim 11
Dependent Claim
33 words
A circuit in accordance with claim 8 in which the first switching device comprises a pnpn device having cathode, anode and gate terminals, which terminals respectively comprise the first, second and third terminals.
Claim 12
Dependent Claim
120 words
A switching circuit in accordance with claim 8 further comprising a second switching device having an internal electrical path between first and second terminals, which electrical path is connected in series with the internal electrical path of the first switching device and operated at the shifted voltage level, the second switching device further having at least a third terminal for receiving signals, and a circuit connected to the third terminal of the second switching device for periodically opening the second switching device in response to a periodic peak of preselected polarity of the cyclically varying bipolar signals to ensure discontinuation of the current flowing through the internal electrical path of the first switching device in response to the disabling signals.
Claim 13
Dependent Claim
52 words
A switching circuit in accordance with claim 10 in which the second switching device comprises a first transistor having an internal electrical path between collector and emitter terminals in series with the first switching device and a base terminal for receiving signals from the circuit for periodically opening the second switching device.
Claim 14
Dependent Claim
61 words
A circuit in accordance with claim 8 in which the means for shifting the average voltage level of the electrical path between the first and second terminals of the first switching device comprises first and second diodes respectively connected to the first and second terminals for clipping the voltage on the terminals thereby preventing the voltage from exceeding a predetermined level.
Claim 15
Dependent Claim
106 words
A switching circuit in accordance with claim 10 wherein the circuit for periodically opening the second switching device comprises a third switching device having an internal electrical path between first and second terminals for conducting a direct current, which conduction is controlled by enabling and disabling signals received at a third terminal, means responsive to periodic peaks of preselected polarity of the cyclically varying signals for enabling and disabling the third switching device, and means for delivering signals generated by the controlled conduction through the third switching device to the third terminal of the second switching device thereby periodically opening and closing the second switching device.
Claim 16
Dependent Claim
124 words
A circuit in accordance with claim 13 wherein the third switching device comprises a second transistor having collector, emitter and base terminals, which terminals are analogous to the first, second and third terminals, respectively, and the means for delivering a signal to the third terminal of the second switching device comprising a capacitor, one terminal of which is connected to the collector of the second transistor and the other terminal to the third terminal of the second switching device, for delivering a signal on the collector of the second transistor, which signal is responsive to the enabling and disabling signals at the base of the second transistor, to the third terminal of the second switching device for opening and closing the second switching device.
Claim 17
Dependent Claim
146 words
A circuit for applying enabling and disabling signals to a switching device having at least first, second and third terminals for conducting an electric current along an internal electrical path between the first and second terminals comprising means for receiving first and second control signals at plural input terminals, means for producing logic state voltages responsive to the first and second control signals, means for storing the logic state voltages, means for cooperating with the means for storing to provide a direct current voltage across the first and third terminals of the switching device and thereby enabling the switching device in response to a predetermined logic state voltage, and means for cooperating with the means for storing to close an electrical path between the first and third terminals of the switching device and thereby disabling the switching device in response to a predetermined logic state voltage.
Claim 18
Dependent Claim
146 words
A circuit for applying enabling and disabling signals to a switching device having at least first, second and third terminals for conducting an electric current along an internal electrical path between the first and second terminals comprising means for receiving first and second control signals at plural input terminals, means for producing logic state voltages responsive to the first and second control signals, means for storing the logic state voltages, means for cooperating with the means for storing to provide a direct current voltage across the first and third terminals of the switching device and thereby enabling the switching device in response to a predetermined logic state voltage, and means for cooperating with the means for storing to close an electrical path between the first and third terminals of the switching device and thereby disabling the switching device in response to a predetermined logic state voltage.
Claim 19
Dependent Claim
136 words
A circuit in accordance with claim 15 in which the means for producing logic state voltages comprises a first IGFET device having at least first, second and control terminals, means for connecting the control terminal to a terminal for receiving the first control signal, which signal defines a periodic time slot during which time slot the second control signal is received for determining whether an enabling or disabling signal is provided to the switching device, and means for applying the second control signal to the first terminal of the first IGFET device, which second control signal is conducted through the first IGFET device during the time slot defined by the first control signal to a capacitor connected to the second terminal of the first IGFET, which capacitor comprises the means for storing the logic state voltages.
Claim 20
Dependent Claim
155 words
A circuit in accordance with claim 15 in which the means for providing a direct current voltage across the first and third terminals of the switching device comprises a second IGFET device having at least first, second and control terminals, means for connecting the control terminal to the second terminal of the first IGFET device, which control terminal receives logic state signals responsive to the first and second control signals, a direct current voltage supply connected across the first terminal of the switching device and the second terminal of the second IGFET device for providing an enabling bias voltage to the switching device, and means for connecting the first terminal of the second IGFET device to the third terminal of the switching device so as to provide the enabling bias voltage to the third terminal of the switching device in response to the logic state signal at the control terminal of the second IGFET device.
Claim 21
Dependent Claim
132 words
A circuit in accordance with claim 15 in which the means for closing an electrical path between the first and third terminals of the switching device comprises a third IGFET device having at least first, second and control terminals, means for connecting the control terminal to the second terminal of the first IGFET device, which control terminal receives logic state signals responsive to the first and second control signals, and means for connecting the first and second terminals of the third IGFET device to the first and third terminals, respectively, of the switching device for providing an electrical path between the first and third terminals of the switching device responsive to the logic state signals at the control terminal of the third IGFET device, which responsive electrical path disables the switching device.
References Cited (Backward Citations)
US3217176A
Cited
US3240916A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-18 | 1981-01-17 | 1981-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-18 | 1985-01-17 | 1985-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-18 | 1989-01-17 | 1989-07-19 | $7700.00 | Window Closed / Lapsed |