Full cycle synchronous-switching control circuit

Claim 2

A synchronous-switching control circuit adapted to enable a load to be selectively energized and de-energized from a source of alternating current at a point of substantially zero circuit current in response to a random actuation and deactuation of a power switch, said control circuit comrpising: means responsive to a predetermined range in the positive portion of the AC waveform of said alternating current for generating a first signal and responsive to a predetermined range in the negative portion of the AC waveform of said alternating current for generating a second signal, gate-controlled, bidirectional current-carrying switching means connected between said source and said load for energizing said load in response to the presence of a gate-biasing potential and for de-energizing said load in response to the absence of said gate-biasing potential, and means responsive to the random actuation of said power switch in conjunction with said first signal for appling said gatebiasing potential to said switching means and responsive to the random deactuation of said power switch in conjunction with said second signal for removing said gate-biasing potential, said responsive means for applying and removing said gate biasing potential includes: a latch flip-flop having first and second stable states, first logical gating means responsive to the random actuation of said power switch in conjunction with said first signal for switching said latch flip-flop to said first stable state, second logical gating means responsive to the random deactuation of said power switch in conjunction with said second signal for switching said latch flip-flop to said second stable state, and circuit means responsive to the first stable state of said latch flip-flop for applying said gate-biasing potential to said switching means and responsive to the second stable state of said latch flip-flop for removing said gate-biasing potential.

Claim 3

The synchronous-switching control circuit of claim 1 wherein said circuit means includes: relay means including a relay coil, said relay means responsive to the first stable state of said latch flip-flop for energizing said relay coil and responsive to the second stable state of said latch flip-flop for de-energizing said relay coil, and means for generating said gate-biasing potential, said generating means including a relay-operating switching means responsive to the energization of said relay coil for applying said gate-biasing potential to said gate-controlled bidirectional switching means and responsive to the de-energization of said relay coil for removing said gate-biasing potentIal from said gate-controlled bidirectional switching means.

Claim 4

The control circuit of claim 2 wherein said gate-controlled bidirectional current-carrying switching means includes a triac having a first load electrode connected to said source of alternating current, a second load electrode connected to said load, and a gate electrode coupled to said means for generating said gate-biasing potential.

Claim 5

A synchronous-switching control circuit adapted to enable a load to be selectively energized and de-energized from a source of alternating current at a point of substantially zero circuit current in response to a random actuation and deactuation of a power switch, said control circuit comprising: means responsive to a predetermined range in the positive portion of the AC waveform of said alternating current for generating a first signal and responsive to a predetermined range in the negative portion of the AC wave form of said alternating current for generating a second signal, gate-controlled, bidirectional current-carrying switching means connected between said source and said load for energizing said load in response to the application of a gate-biasing potential to said switching means and responsive to the random deactuation of said power switch in conjunction with said second signal for removing said gate-biasing potential, and wherein said responsive means for generating said first and second signals includes: first circuit means including a first transistor for generating said first signal upon the attainment of some value within said predetermined range in the positive portion of said AC waveform, and second circuit means including a second sensing transistor for generating said second signal upon the attainment of some value within said predetermined range in the negative portion of said AC waveform.

Claim 6

A synchronous-switching control circuit adapted to enable a load to be selectively energized and de-energized from a source of alternating current at a point of substantially zero circuit current in response to a random actuation and deactuation of a power switch, said control circuit comprising: means responsive to a predetermined range in the positive portion of the AC waveform of said alternating current for generating a first signal and responsive to a predetermined range in the negative portion of the AC wave form of said alternating current for generating a second signal, gate-controlled, bidirectional current-carrying switching means connected between said source and said load for energizing said load in response to the application of a gate-biasing potential to said switching means and responsive to the random deactuation of said power switch in conjunction with said second signal for removing said gate-biasing potential, and wherein said responsive means for generating said first and second signals includes: first circuit means including a first transistor for generating said first signal upon the attainment of some value within said predetermined range in the positive portion of said AC waveform, and second circuit means including a second sensing transistor for generating said second signal upon the attainment of some value within said predetermined range in the negative portion of said AC waveform.

Claim 7

The control circuit of claim 4 wherein said first circuit means includes a first charging capacitor, and a first diode means responsive to the positive portion of said AC waveform for controlling the charging and discharging of said first capacitor, switching said first transistor to a conductive state and generating said first signal, and wherein said second circuit means includes a second charging capacitor, and a second diode means responsive to the negative portion of said AC waveform for controlling the charging and discharging of said second capacitor, triggering said second sensing transistor to a conductive state and producing said second signal.

Claim 8

In a synchronous-switching system wherein a gate-controlled bidirectional switching element is used to control the application of power from an AC source to a load in response to the random actuation and deactuation of a power switch such that a gating potential is applied to the gate of said switching element at that point in the AC cycle at which the source current is approximately zero for driving said switching element into a conductive state, said switching element continuing to energize the load until, in response to the deactuation of said power switch, the gating potential is removed and said switching element is switched to a nonconductive state at that point in the AC cycle at which the load current is approximately zero and said switching element is no longer able to sustain conduction, a control circuit for controlling the application and removal of said gating potential comprising: means for sensing the actuation and deactuation of said power switch; means for detecting a predetermined positive zone in the AC cycle and for detecting a predetermined negative zone in the AC cycle, first logic means responsive to the sensing of said actuation of said power switch and to said means for detecting a positive zone for generating a set signal, second logic means responsive to the sensing of said deactuation of said power switch and to said means for detecting a negative zone for generating a reset signal, and latching means responsive to saId set signal for enabling the application of said gating potential to the gate of said switching element and responsive to said reset signal for enabling the removal of said gating potential from the gate of said switching element.

Claim 9

In a synchronous-switching system wherein a gate-controlled bidirectional switching element is used to control the application of power from an AC source to a load in response to the random actuation and deactuation of a power switch such that a gating potential is applied to the gate of said switching element at that point in the AC cycle at which the source current is approximately zero for driving said switching element into a conductive state, said switching element continuing to energize the load until, in response to the deactuation of said power switch, the gating potential is removed and said switching element is switched to a nonconductive state at that point in the AC cycle at which the load current is approximately zero and said switching element is no longer able to sustain conduction, a control circuit for controlling the application and removal of said gating potential comprising: means for sensing the actuation and deactuation of said power switch; means for detecting a predetermined positive zone in the AC cycle and for detecting a predetermined negative zone in the AC cycle, first logic means responsive to the sensing of said actuation of said power switch and to said means for detecting a positive zone for generating a set signal, second logic means responsive to the sensing of said deactuation of said power switch and to said means for detecting a negative zone for generating a reset signal, and latching means responsive to saId set signal for enabling the application of said gating potential to the gate of said switching element and responsive to said reset signal for enabling the removal of said gating potential from the gate of said switching element.

Claim 10

The control circuit of claim 6 wherein said latching means includes: circuit means including a relay-operated switch, said circuit means including means responsive to the closure of said relay-operated switch for applying said gating potential to the gate of said bidirectional switching element and responsive to the opening of said relay-operated switch for removing said gating potential from the gate of said bidirectional switching element, relay means for controlling said relay-operated switch, and bistable flip-flop means responsive to said set signal for energizing said relay means and closing said relay-operated switch and responsive to said reset signal for de-energizing said relay means and opening said relay-operated switch.

Claim 11

The control circuit of claim 7 wherein said sensing means includes means responsive to the actuation of said power switch for generating a signal indicative thereof and responsive to the deactuation of said power switch for inhibiting the generation of said signal indicative of the actuation of said power switch.

Claim 12

The control circuit of claim 8 wherein said means for detecting a positive zone includes: a first current-conducting means having a first and second current-carrying electrode and a control electrode, first capacitive means coupled to said control electrode for switching said first current-carrying means to a conductive state upon the attainment of a predetermined approximate charge on said capacitive means, and means for charging said first capacitive means only during the positive portion of said AC waveform.

Claim 13

The control circuit of claim 9 wherein said means for detecting a negative zone includes: a second current-carrying element having first and second current-carrying electrodes and a control electrode, second capacitive means coupled to the control electrode of said current-carrying element for switching said current-carying element to a conductive state upon the attainment of a predetermined approximate charge on said capacitive means, and means for charging said second capacitive means only during the negative portion of said AC cycle.

Claim 14

The control circuit of claim 10 wherein said first logic means includes a plurality of logical NAND gates responsive to the generation of said signal indicative of a power switch actuation and to a conductive state of said first current-carrying means for generating said set signal and wherein said second logic means includes a plurality of logical NAND gates responsive to the absence of said signal indicative of a power switch actuation and to a conductive state of second current-carrying means for generating said reset signal.

Claim 15

The synchronous switching system of claim 11 wherein said bidirectional switching element includes a triac, wherein said first current-carrying element and said second current-carrying element are first and second transistors respectively, wherein said first capacitive charging means includes at least one diode, and wherein said second capacitive charging means includes at least one diode.

Claim 16

A control circuit for responding to the actuation of a power switch to couple a source of alternating current to a load at that point in the alternating current cycle at which the magnitude of the source current is approximately zero and for responding to the deactuation of the power switch to de-couple the source from the load at that point in the alternating current cycle at which the load current is approximately zero, said control circuit comprising: gate-controlled switching means, having a first load electrode coupled to said generating of alternating current, a second load electrode coupled to said load, and a gate electrode, said switching meaNs being responsive to the presence of a triggering potential at said gate electrode for switching said switching means into a conductive state and being responsive to the absence of a triggering potential at said gate electrode and to the magnitude of the current passing through said first and second load electrodes falling below a predetermined value required to maintain said switching element in said conductive state for rendering said switching element non-conductive, first sensing means responsive to the actuation of said power switch for generating a first signal and responsive to the deactuation of said power switch for inhibiting the generation of said first signal, second sensing means responsive to a predetermined zone in the positive portion of the waveform of said alternating current, third sensing means responsive to a predetermined zone in the negative portion of the waveform of said alternating current, first logical gating means responsive to said first signal and to said second sensing means for generating a set signal, second logical gating means responsive to the inhibition of said first signal and to said third sensing means for generating a reset signal, bistable latching means including a reed relay, said bistable latching means responsive to said set signal for energizing said reed relay and to said reset signal for de-energizing said reed relay, and means for generating said triggering potential, said triggering potential-generating means including a relay-operated switching means responsive to the energization of said reed relay for applying said triggering potential to said gate electrode and responsive to the de-energization of said reed relay for removing said triggering potential from said gate electrode.

Claim 17

A control circuit for responding to the actuation of a power switch to couple a source of alternating current to a load at that point in the alternating current cycle at which the magnitude of the source current is approximately zero and for responding to the deactuation of the power switch to de-couple the source from the load at that point in the alternating current cycle at which the load current is approximately zero, said control circuit comprising: gate-controlled switching means, having a first load electrode coupled to said generating of alternating current, a second load electrode coupled to said load, and a gate electrode, said switching meaNs being responsive to the presence of a triggering potential at said gate electrode for switching said switching means into a conductive state and being responsive to the absence of a triggering potential at said gate electrode and to the magnitude of the current passing through said first and second load electrodes falling below a predetermined value required to maintain said switching element in said conductive state for rendering said switching element non-conductive, first sensing means responsive to the actuation of said power switch for generating a first signal and responsive to the deactuation of said power switch for inhibiting the generation of said first signal, second sensing means responsive to a predetermined zone in the positive portion of the waveform of said alternating current, third sensing means responsive to a predetermined zone in the negative portion of the waveform of said alternating current, first logical gating means responsive to said first signal and to said second sensing means for generating a set signal, second logical gating means responsive to the inhibition of said first signal and to said third sensing means for generating a reset signal, bistable latching means including a reed relay, said bistable latching means responsive to said set signal for energizing said reed relay and to said reset signal for de-energizing said reed relay, and means for generating said triggering potential, said triggering potential-generating means including a relay-operated switching means responsive to the energization of said reed relay for applying said triggering potential to said gate electrode and responsive to the de-energization of said reed relay for removing said triggering potential from said gate electrode.

Claim 18

The control circuit of claim 13 wherein said gate-controlled switching means includes a triac.

Claim 19

The control circuit of claim 14 wherein said first sensing means includes a first transistor and RC circuit means responsive to the actuation of said power switch for switching said first transistor to a conductive state and generating said first signal at the collector thereof and responsive to the deactuation of said power switch for switching said first transistor to a non-conductive state and inhibiting the generation of said first signal at the collector of said first transistor.

Claim 20

The control circuit of claim 15 wherein said second sensing means includes a second transistor and second circuit means for establishing a predetermined turn-on zone within the positive portion of the waveform of said alternating current and for switching said second transistor to a conductive state at some point within said turn-on zone.

Claim 21

The control circuit of claim 16 wherein said means for establishing a turn-on zone and for switching said second transistor to a conductive state at some pont within said turn-on zone includes a first charging capacitor coupled to the base of said second transistor and first diode means responsive to the positive portion of said AC waveform for charging said first capacitor.

Claim 22

The control circuit of claim 17 wherein said third sensing means includes a third transistor and third circuit means for establishing a predetermined turn-off zone within the negative portion of the waveform of said alternating current and for switching said third transistor to a conductive state at some point within said turn-off zone.

Claim 23

The control circuit of claim 18 wherein said means for establishing a turn-off zone and for switching said third transistor to a conductive state at some point within said turn-off zone includes a second charging capacitor coupled to the base of said third transistor and second diode means responsive to the negative portion of the AC cycle for enabling the charging and discharging of said second charging capacitor.