Solid state relay using photo-coupled isolators

Claim 2

A solid state relay having first and second output terminals, said relay comprising: a. means for receiving a control signal; b. first means including first light emitting means and photo transistor means optically coupled with said first light emitting means; c. second means including second light emitting means and photo silicon controlled rectifier means optically coupled with said second light emitting means; d. transistor means having base, collector and emitter electrodes, said collector and emitter electrodes coupled to said first and second output terminals; e. means for coupling said first and second means in circuit; f. means responsive to said control signal for turning on both said photo silicon controlled rectifier means and said photo transistor means; g. means for coupling said transistor means base to said circuit of said first and sEcond means; and h. means responsive to the turn on of said photo transistor means and said photo silicon controlled rectifier means for turning on said transistor means, whereby a current path is provided between said first and said second output terminals.

Claim 3

A solid state relay comprising: a. means for receiving a control signal; b. first means including a first light emitting diode and a photo transistor optically coupled with said first diode; c. second means including a second light emitting diode and a photo silicon controlled rectifier optically coupled with said second diode; d. said first and second diodes connected in circuit and to said means for receiving; e. transistor means having base, collector and emitter electrodes, said collector and emitter electrodes coupled to positive and negative output terminals of said relay; f. said photo silicon controlled rectifier and said photo transistor being coupled in series circuit, said series circuit connected between said positive terminal and said base electrode of said transistor means.

Claim 4

A solid state relay comprising: a. means for receiving a control signal; b. first means including a first light emitting diode and a photo transistor optically coupled with said first diode; c. second means including a second light emitting diode and a photo silicon controlled rectifier optically coupled with said second diode; d. said first and second diodes connected in circuit and to said means for receiving; e. transistor means having base, collector and emitter electrodes, said collector and emitter electrodes coupled to positive and negative output terminals of said relay; f. said photo silicon controlled rectifier and said photo transistor being coupled in series circuit, said series circuit connected between said positive terminal and said base electrode of said transistor means.

Claim 5

Zener diode means connected in paRallel with said resistive means.

Claim 6

Zener diode means connected in paRallel with said resistive means.

Claim 7

A relay as defined in claim 2 further comprising an output circuit connected between said output terminals, said output circuit including a current source and a load, said means for receiving coupled so that the presence of a control signal produces a current path from said current source through said transistor means and to said load.

Claim 8

A relay as defined in claim 2 wherein said photo transistor includes base, emitter and collector electrodes and wherein said relay further comprises Zener diode means connected between said photo transistor emitter and said photo silicon controlled rectifier for limiting the voltage excursion developed between said photo transistor collector and emitter electrodes.

Claim 9

A relay as defined in claim 4 wherein said first and second diodes are coupled in series circuit between said means for receiving and a first potential.

Claim 10

A relay as defined in claim 4 further comprising logic gate means having inputs coupled to receive input signals and having an output connected to said means for receiving.

Claim 11

A relay as defined in claim 6 further comprising capacitive means coupled between said photo transistor base electrode and said negative terminal.

Claim 12

A solid state relay comprising: a. means for receiving a control signal; b. photo transistor coupled pair means including a first light emitting diode and a photo transistor optically coupled for control by said first diode; c. photo silicon controlled rectifier coupled pair means including a second light emitting diode and a photo silicon controlled rectifier (photo SCR) optically coupled for control by said second diode; d. said first and second diodes connected in circuit and to said means for receiving; e. positive and negative output terminals; f. said photo SCR including gate, anode and cathode electrodes and said photo transistor including base, collector and emitter electrodes, said cathode coupled to said collector and said anode coupled to said positive output terminal; and g. transistor means having base, collector and emitter electrodes, said transistor means base and said photo transistor emitter coupled together at a first point, said first point coupled to said photo SCR gate electrode, said transistor means collector coupled to said positive output terminal, and said transistor means emitter coupled to said negative output terminal.

Claim 13

A solid state relay comprising: a. means for receiving a control signal; b. photo transistor coupled pair means including a first light emitting diode and a photo transistor optically coupled for control by said first diode; c. photo silicon controlled rectifier coupled pair means including a second light emitting diode and a photo silicon controlled rectifier (photo SCR) optically coupled for control by said second diode; d. said first and second diodes connected in circuit and to said means for receiving; e. positive and negative output terminals; f. said photo SCR including gate, anode and cathode electrodes and said photo transistor including base, collector and emitter electrodes, said cathode coupled to said collector and said anode coupled to said positive output terminal; and g. transistor means having base, collector and emitter electrodes, said transistor means base and said photo transistor emitter coupled together at a first point, said first point coupled to said photo SCR gate electrode, said transistor means collector coupled to said positive output terminal, and said transistor means emitter coupled to said negative output terminal.

Claim 14

A relay as defined in claim 8 wherein said first and second diodes are connected in series circuit between said means for receiving and a first potential and further comprising: a. first impedance means connected between said first point and said negative output terminal; b. second impedance means connected in said coupling between said photo SCR gate electrode and said first point, said second impedance means including:

Claim 15

A relay as defined in claim 8 further comprising a logic gate having inputs for receiving a plurality of input signals and having an output for producing said control signal, said output coupled to said means for receiving so that the presence of all of said plurality of input signals turns off said first and second diodes making said transistor means non-conductive.

Claim 16

A relay as defined in claim 8 further comprising a logic gate having inputs for receiving a plurality of input signals and having an output for producing said control signal, said output coupled to said means for receiving so that the presence of all of said plurality of input signals turns on said first and second diodes making said transistor means conductive.

Claim 17

A solid state relay comprising: a. means for receiving a control signal; b. first means including a first light emitting diode and a photo transistor optically coupled with said first diode; c. second means including a second light emitting diode and a photo silicon controlled rectifier optically coupled with said second diode; d. said first and second diodes connected in circuit and to said means for receiving; e. transistor means; and wherein f. said photo silicon controlled rectifier and said photo transistor are coupled in circuit and to said transistor means for control of said transistor means.

Claim 18

A solid state relay comprising: a. means for receiving a control signal; b. first means including a first light emitting diode and a photo transistor optically coupled with said first diode; c. second means including a second light emitting diode and a photo silicon controlled rectifier optically coupled with said second diode; d. said first and second diodes connected in circuit and to said means for receiving; e. transistor means; and wherein f. said photo silicon controlled rectifier and said photo transistor are coupled in circuit and to said transistor means for control of said transistor means.