Remote sensing voltage clamping circuit

Claim 2

In a system having a power source, a load circuit at a remote location from the power source, a power lead interconnEcting said power source and said load circuit, improved means for preventing an overvoltage level at said load circuit, said improved means comprising: a voltage sensing lead; means for coupling one end of said sensing lead to said load circuit for sensing the load voltage level at said load circuit supplied from said power source; an overvoltage detecting circuit adjacent said power source, including means for detecting a sensed voltage level greater than a reference voltage level; means for coupling said reference voltage level to said overvoltage detecting circuit; means for coupling the other end of said sensing lead to said overvoltage detecting circuit to provide said sensed voltage level proportionate to said load voltage level; a voltage clamping circuit intermediate said overvoltage detector circuit and said power source, said voltage clamping circuit including means responsive to the detection of a sensed voltage level greater than said reference voltage level for clamping the output of said power source so as not to exceed said overvoltage level at the load circuit.

Claim 3

The improvement of claim 1, wherein said overvoltage detecting circuit includes positive and negative detecting means for detecting positive and negative overvoltage levels at said load circuit.

Claim 4

The improvement of claim 2, wherein said negative detecting means includes an operational amplifier having an inverting input and a non-inverting input; means for applying said sensed voltage level to said non-inverting input; and means for applying said reference voltage level to said inverting input.

Claim 5

The improvement of claim 3, wherein said positive detecting means includes an operational amplifier having an inverting input and a non-inverting input; means for inverting said sensed voltage level and applying the inverted level to said non-inverting input; and means for applying said reference voltage level to said inverting input.

Claim 6

The improvement of claim 4, wherein said voltage clamping circuit includes a diode; means for coupling said diode to the output of said operational amplifier associated with said negative detecting means; and means for forward biasing said diode in response to the detection of a sensed voltage level greater than said reference voltage level.

Claim 7

The improvement of claim 5, wherein said voltage clamping circuit further includes a second diode; means for coupling said second diode to the output of said operational amplifier associated with said positive detecting means; and means for forward biasing said second diode in response to the detection of a sensed voltage level greater than said reference voltage level.

Claim 8

Apparatus for sensing the load voltage level at a load circuit remotely located from an associated power source and preventing undesired overvoltage levels at said load, said apparatus comprising: a high impedance sensing lead having one end coupled to said load circuit at said remote location and the other end extending from said load circuit to the location of said power source, and including means for providing a sensing signal proportionate to said load voltage level; an overvoltage detecting and clamping circuit for detecting approaching positive and negative overvoltage levels at said load circuit and clamping said load voltage level so as not to exceed said overvoltage level; said overvoltage detecting and clamping circuit including; a first amplifier circuit having respective inverting and non-inverting inputs and an output; a second amplifier circuit having respective inverting and non-inverting inputs and an output; means for applying said sensing signal to the inverting input of said first amplifier circuit; inverting means for inverting said sensing signal; means for coupling said inverted sensing signal to the non-inverting input of said second amplifier circuit; reference voltage means including means for coupling a reference voltage level respectively to The non-inverting input of said first amplifier circuit and to the inverting input of said second amplifier circuit; and respective clamping means responsive to said sensing signal and said reference voltage level at said respective first and second amplifier circuits for providing a respective clamping signal to clamp said load voltage level substantially at said overvoltage level when said sensing signal approaches respective positive or negative overvoltage levels.

Claim 9

Apparatus for sensing the load voltage level at a load circuit remotely located from an associated power source and preventing undesired overvoltage levels at said load, said apparatus comprising: a high impedance sensing lead having one end coupled to said load circuit at said remote location and the other end extending from said load circuit to the location of said power source, and including means for providing a sensing signal proportionate to said load voltage level; an overvoltage detecting and clamping circuit for detecting approaching positive and negative overvoltage levels at said load circuit and clamping said load voltage level so as not to exceed said overvoltage level; said overvoltage detecting and clamping circuit including; a first amplifier circuit having respective inverting and non-inverting inputs and an output; a second amplifier circuit having respective inverting and non-inverting inputs and an output; means for applying said sensing signal to the inverting input of said first amplifier circuit; inverting means for inverting said sensing signal; means for coupling said inverted sensing signal to the non-inverting input of said second amplifier circuit; reference voltage means including means for coupling a reference voltage level respectively to The non-inverting input of said first amplifier circuit and to the inverting input of said second amplifier circuit; and respective clamping means responsive to said sensing signal and said reference voltage level at said respective first and second amplifier circuits for providing a respective clamping signal to clamp said load voltage level substantially at said overvoltage level when said sensing signal approaches respective positive or negative overvoltage levels.

Claim 10

Apparatus according to claim 7, wherein said inverting means includes an inverting amplifier and means coupling said sensing signal to the input of said inverting amplifier.