Light-coupled, voltage-controlled constant-power source

Claim 2

Means for supplying a constant power to a varying resistive element comprising: means responsive to the voltage drop across said element for generating a control current which is directly proportional to said voltage drop; means responsive to said control current for generating radiant energy; a source of a first control voltage; means responsive to said first control voltage and said radiant energy for generating a second control voltage; and, means responsive to said second control voltage for controlling current through said element.

Claim 3

Means as recited in claim 1 wherein said radiant energy generating means comprises a light-emitting diode.

Claim 4

Means as recited in claim 2 wherein said means for generating a second control voltage comprises: means responsive to said first control voltage for generating a second current; and, photosensitive resistive means responsive to said radiant energy and disposed to sample said second current, the voltage drop across said photosensitive resistive means being related to said second control voltage.

Claim 5

Means as recited in claim 3 with additionally means for mounting said light-emitting diode in a fixed, predetermined position with respect to said photosensitive resistive means.

Claim 6

Means as recited in claim 3 with additionally mounting means for maintaining the radiant energy coupling factor between said light-emittIng diode and said photosensitive resistive means constant over the operating range of said constant-power means.

Claim 7

A constant-power source for a resistive element comprising: means responsive to the voltage across said element for generating radiant energy; a source of a first control voltage external to said constant-power source; means responsive to said first control voltage and said radiant energy for generating a second control voltage; and, means responsive to said second control voltage for controlling current through said element.

Claim 8

A constant-power source for a resistive element comprising: means responsive to the voltage across said element for generating radiant energy; a source of a first control voltage external to said constant-power source; means responsive to said first control voltage and said radiant energy for generating a second control voltage; and, means responsive to said second control voltage for controlling current through said element.

Claim 9

A constant-power source as recited in claim 6 wherein said second control voltage generating means comprises: means responsive to said first control voltage for generating a first control current; variable resistance means responsive to said radiant energy and said first control current for generating said second control voltage.

Claim 10

A constant-power source as recited in claim 7 wherein said radiant energy generating means comprises means responsive to said voltage across said element for generating a second control current and means responsive to said second control current for generating said radiant energy.

Claim 11

A constant-power source as recited in claim 8 wherein said radiant energy generating means comprises a light-emitting diode and said variable resistance means comprises a photosensitive resistor.

Claim 12

A constant-power source for a resistive load comprising: a load current generator responsive to a first control signal for regulating current through said load, the resultant voltage drop across said load comprising a load voltage; means responsive to said load voltage for generating a second current; means responsive to said second current for generating a feedback signal; a second control signal source external to said constant-power source; and, means responsive to said second control signal and said feedback signal for generating said first control signal.

Claim 13

A constant-power source for a resistive load comprising: a load current generator responsive to a first control signal for regulating current through said load, the resultant voltage drop across said load comprising a load voltage; means responsive to said load voltage for generating a second current; means responsive to said second current for generating a feedback signal; a second control signal source external to said constant-power source; and, means responsive to said second control signal and said feedback signal for generating said first control signal.

Claim 14

A constant-power source as recited in claim 10 wherein said first control signal generating means comprises: means responsive to said second control signal for generating a third current; and, means responsive to said feedback signal and said third current for generating said first control signal.

Claim 15

A constant-power source as recited in claim 11 wherein said means for generating a feedback signal comprises a light-emitting diode, said feedback signal comprising radiant energy generated thereby and arranged to sample said second current; and, wherein said means for generating said first control signal comprises a photosensitive resistor responsive to said radiant energy and arranged to sample said third current, a resultant voltage drop across said photosensitive resistor comprising said first control signal.

Claim 16

A constant-power source as recited in claim 12 wherein said light-emitting diode and said photosensitive resistor are physically fixed with respect to one another.

Claim 17

A constant-power source for a resistive load comprising: a direct current source having first and second terminals, said resistive load having one end connected to said second terminal, and a second end; a first resistor having one end connected to said first terminal, and a second end a first transistor having a base electrode and a collector-emitter circuit for connecting said first resistor and said resistive load second ends; a light-emitting diode having one end connected to said first terminal, and a second end; a second resistor having one end connected to said second terminal, and a second end; a second transistor having a base terminal connected to said resistive load second end, and a collector-emitter circuit for connecting said light-emitting diode second end with said second resistor second end; a photosensitive resistor having one end connected to said first terminal, and a second end; a third resistor having one end connected to said second terminal, and a second end; a control voltage source; a third transistor having a base electrode connected to said control voltage source, and a collector-emitter circuit for connecting said photosensitive resistor second end with said third resistor second end; and, means connecting said photosensitive resistor second end to said first transistor base electrode.

Claim 18

A constant-power source for a resistive load comprising: a direct current source having first and second terminals, said resistive load having one end connected to said second terminal, and a second end; a first resistor having one end connected to said first terminal, and a second end a first transistor having a base electrode and a collector-emitter circuit for connecting said first resistor and said resistive load second ends; a light-emitting diode having one end connected to said first terminal, and a second end; a second resistor having one end connected to said second terminal, and a second end; a second transistor having a base terminal connected to said resistive load second end, and a collector-emitter circuit for connecting said light-emitting diode second end with said second resistor second end; a photosensitive resistor having one end connected to said first terminal, and a second end; a third resistor having one end connected to said second terminal, and a second end; a control voltage source; a third transistor having a base electrode connected to said control voltage source, and a collector-emitter circuit for connecting said photosensitive resistor second end with said third resistor second end; and, means connecting said photosensitive resistor second end to said first transistor base electrode.