Surge protection circuit

Claim 2

A regulated power supply of the type in which a reference potential source is used as a standard against which the output voltage or current is compared, wherein the improvement comprises a surge protection circuit for turning off the supply when the potential input to the supply exceeds a predetermined potential level including a device that is normally nonconductive and that becomes conductive when subjected to a potential approximately equal in magnitude to said predetermined level, series circuit means connecting said device across the potential input to the supply, and shutdown means connected to the reference potential source for greatly reducing the magnitude of the reference potential upon sensing a flow of current through said device.

Claim 3

A surge protection circuit for turning off a regulated power supply when the potential input to the supply exceeds a predetermined potential level, said circuit comprising: a device that is normally nonconductive, and that becomes conductive when subjected to a potential approximately equal in level to said predetermined potential level; series circuit means connecting said device across the potential input to the supply; signal amplification means included in said series circuit means for producing a shutdown current in response to current flow through said device; and shutdown means within said supply for turning off said supply in response to said shutdown current.

Claim 4

A surge protection circuit for turning off a regulated power supply when the potential input to the supply exceeds a predetermined potential level, said circuit comprising: a device that is normally nonconductive, and that becomes conductive when subjected to a potential approximately equal in level to said predetermined potential level; series circuit means connecting said device across the potential input to the supply; signal amplification means included in said series circuit means for producing a shutdown current in response to current flow through said device; and shutdown means within said supply for turning off said supply in response to said shutdown current.

Claim 5

A surge protection circuit in accordance with claim 2 wherein the device is a reverse-biased Zener diode having a Zener potential level approximately equal to said predetermined potential level.

Claim 6

A surge protection circuit in accordance with claim 2 wherein the series circuit means comprises the amplification means and at least one resistive element connected in series with said device to form a series circuit, and wherein said series circuit is connected across the potential input to the supply.

Claim 7

A surge protection circuit in accordance with claim 2 wherein the regulated power supply includes a potential reference device that is supplied with a current, and wherein the shutdown means comprises means for terminating this current whenever the shutdown current is flowing.

Claim 8

A surge protection circuit in accordance with claim 2 wherein the regulated power supply includes a refeRence potential, and wherein the shutdown means comprises means for greatly reducing the magnitude of this reference potential.

Claim 9

A surge protection circuit in accordance with claim 2 wherein the regulated power supply includes a series regulating element, and wherein the shutdown means comprises means for halting the flow of current through this series regulating element.

Claim 10

A surge protection circuit for turning off a regulated power supply when the potential input to the supply exceeds a predetermined potential level, said power supply including a constant current source having a shutdown node, said circuit comprising: a device that is normally nonconductive, and that becomes conductive when subjected to a potential approximately equal in level to said predetermined potential level; series circuit means connecting said device across the potential input to said supply; and amplification means for amplifying current flow through said device into a shutdown current which is fed into the shutdown node within the constant current source.

Claim 11

A surge protection circuit for turning off a regulated power supply when the potential input to the supply exceeds a predetermined potential level, said power supply including a constant current source having a shutdown node, said circuit comprising: a device that is normally nonconductive, and that becomes conductive when subjected to a potential approximately equal in level to said predetermined potential level; series circuit means connecting said device across the potential input to said supply; and amplification means for amplifying current flow through said device into a shutdown current which is fed into the shutdown node within the constant current source.

Claim 12

A surge protection circuit in accordance with claim 8 wherein the constant current source within the supply feeds current to a Zener diode reference potential circuit within the supply.

Claim 13

A surge protection circuit for generating a shutdown current in response to the potential level of a potential source exceeding a predetermined maximum, said circuit comprising: a device that is normally nonconductive, and that becomes conductive when subjected to a potential approximately equal in level to said predetermined level; and a series circuit connected across said potential source, and including: said device, a first current-limiting resistor connected directly to said device to form a series subcircuit, a transistor having emitter, base, and collector electrodes, and having its base electrode connected to said series subcircuit, and a second current limiting resistor connected to the emitter electrode of said transistor; whereby a shutdown current flows from the collector electrode of said transistor when the potential level of the potential source exceeds the predetermined maximum.

Claim 14

A surge protection circuit for generating a shutdown current in response to the potential level of a potential source exceeding a predetermined maximum, said circuit comprising: a device that is normally nonconductive, and that becomes conductive when subjected to a potential approximately equal in level to said predetermined level; and a series circuit connected across said potential source, and including: said device, a first current-limiting resistor connected directly to said device to form a series subcircuit, a transistor having emitter, base, and collector electrodes, and having its base electrode connected to said series subcircuit, and a second current limiting resistor connected to the emitter electrode of said transistor; whereby a shutdown current flows from the collector electrode of said transistor when the potential level of the potential source exceeds the predetermined maximum.

Claim 15

A surge protection circuit in accordance with claim 10 and further including a second Zener diode connecting the emitter electrode of said transistor to the end of said second current-limiting resistor that does not connect to the emitter of said transistor.

Claim 16

A regulated power supply for regulating the flow of power from a power source to a load, said supply comprising: a series regulating element; a first series circuit connected across said power source, and including said series regulating element and the load; a reference potential source; feedback circuit means for comparing the potential across said load with the potential across said reference potential source, and for adjusting the conduction of said series regulating element to maintain the ratio of these two potentials substantially constant; a device that is normally nonconductive and that becomes conductive when subjected to a potential which exceeds a predetermined potential level; a second series circuit connected across said power source and including said device; and shutdown means responsive to current flow through said device for greatly reducing the potential generated by the reference potential source, whereby the power supply ceases to pass current to the load when the potential of the power source exceeds a predetermined potential level.

Claim 17

A regulated power supply for regulating the flow of power from a power source to a load, said supply comprising: a series regulating element; a first series circuit connected across said power source, and including said series regulating element and the load; a reference potential source; feedback circuit means for comparing the potential across said load with the potential across said reference potential source, and for adjusting the conduction of said series regulating element to maintain the ratio of these two potentials substantially constant; a device that is normally nonconductive and that becomes conductive when subjected to a potential which exceeds a predetermined potential level; a second series circuit connected across said power source and including said device; and shutdown means responsive to current flow through said device for greatly reducing the potential generated by the reference potential source, whereby the power supply ceases to pass current to the load when the potential of the power source exceeds a predetermined potential level.

Claim 18

A regulated power supply in accordance with claim 12 which also includes a constant source supplying a constant current to the regulating element, and wherein the shutdown means stops the flow of current from the constant current source.

Claim 19

A surge protection circuit for turning off a regulated power supply when the potential input to the supply exceeds a predetermined potential level, said circuit comprising: a deviCe that is normally nonconductive and that becomes conductive when subjected to a potential approximately equal in level to said predetermined potential level; series circuit means connecting said device across the potential input to the supply; signal amplification means comprising a transistor having emitter and base leads included in said series circuit means and having a collector lead out of which a shutdown current flows in response to current flow through said device; and shutdown means within said supply for turning off said supply in response to said shutdown current.

Claim 20

A surge protection circuit for turning off a regulated power supply when the potential input to the supply exceeds a predetermined potential level, said circuit comprising: a deviCe that is normally nonconductive and that becomes conductive when subjected to a potential approximately equal in level to said predetermined potential level; series circuit means connecting said device across the potential input to the supply; signal amplification means comprising a transistor having emitter and base leads included in said series circuit means and having a collector lead out of which a shutdown current flows in response to current flow through said device; and shutdown means within said supply for turning off said supply in response to said shutdown current.

Claim 21

A surge protection circuit for turning off a regulated power supply when the potential input to the supply exceeds a predetermined potential level, said circuit comprising: a device that is normally nonconductive, and that becomes conductive when subjected to a potential approximately equal in level to said predetermined level; series circuit means connecting said device across the potential input to said supply; amplification means for amplifying current flow through said device into a shutdown current; and a constant current source comprising a reference potential source having two terminals; a transistor having emitter, base, and collector electrodes, and having its base electrodes connected to one terminal of said reference source, and having the constant current flowing from its collector electrode; and a resistor connecting the emitter electrode of said transistor to the remaining terminal of said reference potential source, said shutdown current being fed into the node formed by the junction of said resistor with said emitter electrode.

Claim 22

A surge protection circuit for turning off a regulated power supply when the potential input to the supply exceeds a predetermined potential level, said circuit comprising: a device that is normally nonconductive, and that becomes conductive when subjected to a potential approximately equal in level to said predetermined level; series circuit means connecting said device across the potential input to said supply; amplification means for amplifying current flow through said device into a shutdown current; and a constant current source comprising a reference potential source having two terminals; a transistor having emitter, base, and collector electrodes, and having its base electrodes connected to one terminal of said reference source, and having the constant current flowing from its collector electrode; and a resistor connecting the emitter electrode of said transistor to the remaining terminal of said reference potential source, said shutdown current being fed into the node formed by the junction of said resistor with said emitter electrode.

Claim 23

A regulated power supply for regulating the flow of power from a power source to a load, said supply comprising: a series regulating element; a first series circuit connected across said power source and including said series regulating element and the load; a reference potential source; feedback circuit means for comparing the potential across said load with the potential across said reference potential source and for adjusting the conduction of said series regulating element to maintain the ratio of these two potentials substantially constant; a device that is normally nonconductive and that becomes conductive when subjected to a potential which exceeds a predetermined potential level; a second series circuit connected across said power source and including said device; shutdown means responsive to current flow through said device for producing a current; and a transistor connected to said reference potential source and to the current generated by the shutdown means in such a manner that current flow from the shutdown means causes the transistor to reduce the magnitude of the reference potential, whereby the power supply ceases to pass current to the load when the potential input to the power source exceeds a predetermined potential level.

Claim 24

A regulated power supply for regulating the flow of power from a power source to a load, said supply comprising: a series regulating element; a first series circuit connected across said power source and including said series regulating element and the load; a reference potential source; feedback circuit means for comparing the potential across said load with the potential across said reference potential source and for adjusting the conduction of said series regulating element to maintain the ratio of these two potentials substantially constant; a device that is normally nonconductive and that becomes conductive when subjected to a potential which exceeds a predetermined potential level; a second series circuit connected across said power source and including said device; shutdown means responsive to current flow through said device for producing a current; and a transistor connected to said reference potential source and to the current generated by the shutdown means in such a manner that current flow from the shutdown means causes the transistor to reduce the magnitude of the reference potential, whereby the power supply ceases to pass current to the load when the potential input to the power source exceeds a predetermined potential level.