Switching circuit

Claim 2

In a switching circuit, a. a first control means having a power circuit and a control circuit, b. means for connecting a signal source to the control circuit of said first control means, c. a first charging circuit, d. a second control means having a power circuit and a control circuit, e. a second charging circuit functioning to charge when said second control means is conducting, f. said first charging circuit being coupled to the control circuit of said second control means and also being coupled to the power circuit of said first control means so as to charge when said first control means is conducting, said first charging circuit serving to activate said second control means upon reaching a predetermined level, g. said second charging circuit being coupled to the power circuit of said first control means and when having a charge lowering the signal level required to keep said first control circuit turned on.

Claim 3

In a switching circuit having a controlled hysteresis between the turn on and turnoff points, a. an AC power source, b. a first control means having a power circuit and a control circuit, said AC power source being coupled to said power circuit of said first control means, c. means for connecting a signal source to the control circuit of said first control means, d. a first charging circuit coupled to the power circuit of said first control means and serving to charge when said signal source reaches a predetermined level and causes said first control means to conduct, e. a second circuit means having a control and a power circuit with the power circuit thereof being coupled to said AC power source, f. said first charging circuit being coupled to the control circuit of said second control means and serving to cause said second control means to conduct when the first charging circuit reaches a predetermined level, g. a second charging circuit functioning to charge when said second control means is conducting, and h. means coupling said second charging circuit to the power circuit of said first control means when the latter is conducting to thereby require a different signal level to turn said first control means off than is required to turn it on.

Claim 4

In a switching circuit having a controlled hysteresis between the turn on and turnoff points, a. an AC power source, b. a first control means having a power circuit and a control circuit, said AC power source being coupled to said power circuit of said first control means, c. means for connecting a signal source to the control circuit of said first control means, d. a first charging circuit coupled to the power circuit of said first control means and serving to charge when said signal source reaches a predetermined level and causes said first control means to conduct, e. a second circuit means having a control and a power circuit with the power circuit thereof being coupled to said AC power source, f. said first charging circuit being coupled to the control circuit of said second control means and serving to cause said second control means to conduct when the first charging circuit reaches a predetermined level, g. a second charging circuit functioning to charge when said second control means is conducting, and h. means coupling said second charging circuit to the power circuit of said first control means when the latter is conducting to thereby require a different signal level to turn said first control means off than is required to turn it on.

Claim 5

A switching circuit as claimed in claim 2 wherein said second control means is an SCR and the gate thereof is coupled to said first charging circuit.

Claim 6

A switching circuit as claimed in claim 2 wherein said first control means is a transistor having an emitter and a collector in the power circuit thereof and wherein said second charging circuit is coupled to the power circuit of said transistor.

Claim 7

A switching circuit as claimed in claim 2 wherein a load is connected to the power circuit of said second control means and said second charging means includes a capacitor coupled across said load.

Claim 8

A switching circuit as claimed in claim 2 wherein a third control means having control and power circuits is connected in back-to-back relationship with said second control means, and wherein a third charging circuit is provided which is charged when said second control means is conducting, and wherein said third charging circuit is coupled to the control circuit of said third control means.

Claim 9

A switching circuit as claimed in claim 6, wherein said second and third switching means are semiconductor devices.

Claim 10

A switching circuit as claimed in claim 2, wherein means are provided for varying the on to off time of the switching circuit by canceling at least a portion of the signal supplied to said control circuit of said first control means.

Claim 11

A switching circuit as claimed in claim 8, wherein said means for canceling a portion of said signal includes a charging circuit which is charged from the power circuit of said second control means and in turn applies a canceling voltage to said signal applied to the control circuit of said first control means.

Claim 12

A switching circuit as claimed in claim 9 wherein means are provided for applying a reset signal to said first control means.

Claim 13

In a switching circuit having a controlled differential between its turn on and turnoff points, a. a power source, b. a first control means having a power circuit and a control circuit, said first control means having its power circuit coupled to said power source, c. means for connecting an error signal to said control circuit of said first control means, d. a second control means, e. said first control means and said second control means being operably connected to conduct approximately 180* out of phase with respect tO one another, f. means coupled to the power circuit of said first control means and to said second control means for activating said second control means when said first control means has conducted at a predetermined level, and g. means activated when said second control means is conducting and coupled between said second control means and the power circuit of said first control means to increase the power conducted through the power circuit of said first control means when the latter is conducting to thereby require a predetermined drop in error signal applied to said control circuit of said first control means before said switching circuit will turn off.

Claim 14

In a switching circuit having a controlled differential between its turn on and turnoff points, a. a power source, b. a first control means having a power circuit and a control circuit, said first control means having its power circuit coupled to said power source, c. means for connecting an error signal to said control circuit of said first control means, d. a second control means, e. said first control means and said second control means being operably connected to conduct approximately 180* out of phase with respect tO one another, f. means coupled to the power circuit of said first control means and to said second control means for activating said second control means when said first control means has conducted at a predetermined level, and g. means activated when said second control means is conducting and coupled between said second control means and the power circuit of said first control means to increase the power conducted through the power circuit of said first control means when the latter is conducting to thereby require a predetermined drop in error signal applied to said control circuit of said first control means before said switching circuit will turn off.

Claim 15

A switching circuit as claimed in claim 11 wherein said means to increase the power in said first control means is applied as a positive feedback voltage to the power circuit of said first control means.

Claim 16

A switching circuit as claimed in claim 11 wherein said power source is AC and means are provided for switching said circuit on and off at the zero voltage crossing of the said AC source.