Switching circuits

Claim 2

A switching circuit comprising: a. a controlled bidirectional gate device having a first terminal electrode, a second terminal electrode, and a control electrode, said device becoming conductive in a first direction between said terminal electrodes when a signal of sufficient value and of a given polarity is applied to said control electrode and when a voltage above a first threshold value of insignificant magnitude and of one polarity is applied across said first and second terminal electrodes, said device becoming conductive in the opposite direction between said terminal electrodes when a signal of sufficient value and of a given polarity is applied to said control electrode and when a voltage above a second threshold value of insignificant magnitude and of a polarity opposite to said one polarity is applied across said terminal electrodes; b. means for connecting a load in circuit with said first and second terminal electrodes of said gate device and the first and second terminals of an alternating current source of the type having a first terminal, a second terminal, and a third intermediate terminal adapted for connection to a point of reference potential; c. a time constant circuit connected in circuit with a given one of said first and second terminals of said current source and said third terminal of said current source, said time constant circuit having a charge path of a first time constant including an energy storage device and having a discharge path of a second time constant including said energy storage device; d. means for charging said storage device over said time constant charging path whenever said alternating current source is of a given polarity, said storage device charging only when said alternating current source is of said given polairty; and e. means connected to the control electrode of said bidirectional gate device for discharging said storage device over said time constant circuit discharge path and through said control electrode, the discharge duration of said discharge path being sufficiently long to cause said gate device to become conductive in said first direction during the half cycle of alternating current of said given polarity and in said opposite direction during the opposite half cycle of said alternating current.

Claim 3

The invention as set forth in claim 1 further comprising means connected to said time constant circuit charge path for controlling the level to which said energy storage device will charge.

Claim 4

The invention as set forth in claim 2 wherein means are provided selectively permitting and preventing charging of said time constant circuit, to turn said charging means on and off.

Claim 5

The invention as set forth in claim 2 wherein said charging means includes a device which has controlled conducting and nonconducting states connected in circuit with said time constant circuit between said intermediate terminal and said given terminal of said source.

Claim 6

The invention as set forth in claim 2 wherein said charging means is further defined as comprising a semiconductor diode poled to conduct only when said alternating current is of said given polarity.

Claim 7

The invention as set forth in claim 2 wherein said means connected to the control electrode of said bidirectional gate device is further defined as comprising a semiconductor diode.

Claim 8

A switching circuit which substantially avoids the generation thereby of switching transients and the accompanying interference associated therewith comprising: a. first and second input terminals adapted for connection to a source of alternating current and a third input terminal adapted for connection to a point of reference potential; b. a load; c. a controlled bidirectional gate device having a first terminal electrode, a second terminal electrode, and a control electrode, said device becoming conductive in a first direction between said terminal electrodes when a signal of sufficient value and of a given polarity is applied to said control electrode and when a voltage above a first threshold value of insignificant magnitude and of one polarity is applied across said first and second terminal electrodes, said device becoming conductive in the opposite direction between said terminal electrodes when a signal of sufficient value and of a given polarity is applied to said control electrode and when a voltage above a second threshold value of insignificant magnitude and of a polarity opposite to said one polarity is applied across said terminal electrodes; d. a connection from said first input terminal through said load to a given one of said terminal electrodes of said gate device; e. a connection from said second input terminal to the remaining one of said terminal electrodes of said gate device; f. a time constant circuit connected in circuit with said second and third input terminals, said time constant circuit having a charge path of a first time constant including an energy storage device and having a discharge path of a second time constant including said energy storage device; g. means for charging said storage device over said time constant charging path whenever said alternating current source is of a given polarity, said storage device charging only when said alternating current source is of said given polarity; and h. means connected to the control electrode of said bidirectional gate device for discharging said storage device over said time constant circuit discharge path and through said control electrode, the discharge duration of said discharge path being sufficiently long to cause said gate device to become conductive in said first direction during the half cycle of alternating current of said given polarity and in said opposite direction during the opposite half cycle of said alternating current.

Claim 9

A switching circuit which substantially avoids the generation thereby of switching transients and the accompanying interference associated therewith comprising: a. first and second input terminals adapted for connection to a source of alternating current and a third input terminal adapted for connection to a point of reference potential; b. a load; c. a controlled bidirectional gate device having a first terminal electrode, a second terminal electrode, and a control electrode, said device becoming conductive in a first direction between said terminal electrodes when a signal of sufficient value and of a given polarity is applied to said control electrode and when a voltage above a first threshold value of insignificant magnitude and of one polarity is applied across said first and second terminal electrodes, said device becoming conductive in the opposite direction between said terminal electrodes when a signal of sufficient value and of a given polarity is applied to said control electrode and when a voltage above a second threshold value of insignificant magnitude and of a polarity opposite to said one polarity is applied across said terminal electrodes; d. a connection from said first input terminal through said load to a given one of said terminal electrodes of said gate device; e. a connection from said second input terminal to the remaining one of said terminal electrodes of said gate device; f. a time constant circuit connected in circuit with said second and third input terminals, said time constant circuit having a charge path of a first time constant including an energy storage device and having a discharge path of a second time constant including said energy storage device; g. means for charging said storage device over said time constant charging path whenever said alternating current source is of a given polarity, said storage device charging only when said alternating current source is of said given polarity; and h. means connected to the control electrode of said bidirectional gate device for discharging said storage device over said time constant circuit discharge path and through said control electrode, the discharge duration of said discharge path being sufficiently long to cause said gate device to become conductive in said first direction during the half cycle of alternating current of said given polarity and in said opposite direction during the opposite half cycle of said alternating current.

Claim 10

A switching circuit as defined in claim 7 further comprising means connected to said time constant circuit charging path for controlling the level to which said energy storage device will charge.

Claim 11

A switching circuit as defined in claim 8 wherein means are provided selectively permitting and prevEnting charging of said time constant circuit, to turn said charging means on and off.

Claim 12

The invention as set forth in claim 8 wherein said charging means is further defined as comprising a semiconductor diode poled to conduct only when said alternating current is of said given polarity.

Claim 13

The invention as set forth in claim 8 wherein said means connected to the control electrode of said bidirectional gate device is further defined as comprising a semiconductor diode.

Claim 14

The invention as set forth in claim 8 wherein said charging means includes a device which has controlled conducting and nonconducting states connected in circuit with said time constant between said second and third input terminals.

Claim 15

A power control circuit comprising: a. a triac having first and second main terminal electrodes and a control electrode; b. means for connecting a load in circuit with said main terminal electrodes and with the first and second terminals of an AC source of the type having a first terminal, a second terminal, and a third terminal adapted for connection to a point of reference potential; c. a time constant circuit connected in circuit with said third terminal and a given one of said first and second terminals of said AC source, said time constant circuit having a charge path of a first time constant including an energy storage device and having a discharge path of a second time constant including said energy storage device; d. means for charging said storage device over said time constant circuit charge path whenever said AC source is of a given polarity, said storage device charging only when said AC source is of said given polarity; and e. means for discharging said storage device over said time constant circuit discharge path and through said control electrode, the discharge duration of said discharging means being sufficiently long to trigger said triac into conduction in a first direction during the AC half cycle of said given polarity and in the opposite direction during the opposite half cycle of said AC source.

Claim 16

A power control circuit comprising: a. a triac having first and second main terminal electrodes and a control electrode; b. means for connecting a load in circuit with said main terminal electrodes and with the first and second terminals of an AC source of the type having a first terminal, a second terminal, and a third terminal adapted for connection to a point of reference potential; c. a time constant circuit connected in circuit with said third terminal and a given one of said first and second terminals of said AC source, said time constant circuit having a charge path of a first time constant including an energy storage device and having a discharge path of a second time constant including said energy storage device; d. means for charging said storage device over said time constant circuit charge path whenever said AC source is of a given polarity, said storage device charging only when said AC source is of said given polarity; and e. means for discharging said storage device over said time constant circuit discharge path and through said control electrode, the discharge duration of said discharging means being sufficiently long to trigger said triac into conduction in a first direction during the AC half cycle of said given polarity and in the opposite direction during the opposite half cycle of said AC source.

Claim 17

The invention as set forth in claim 13 further comprising means connected to said time constant circuit charge path for controlling the level to which said energy storage device will charge.