Modulated energy conservative current supply

Claim 2

An energy conservative current system comprising: a current load and an amplifier driving said current load with negative feedback from said current load in response to input signals indicative of the current desired in said load; a source of substantially constant current of a magnitude of current to be delivered to said current load; and means responsive to input signals applied to said amplifier of either polarity in excess of given magnitude for connecting said current source in a corresponding polarity to said current load, the current in said current load being the summation of the current from said constant current source and the current from said negative feedback amplifier, said negative feedback amplifier being responsive to the current through said current load to provide a current equal to the difference between the current supplied by said constant current source and the current desired in said load as indicated by the amplifier input signals, said means also being responsive to the absence of input signals to said amplifier in excess of said given magnitude for disconnecting said current source from said amplifier.

Claim 3

A current source comprising: a DC power supply, a large inductance, and a switch connected between said power supply and said inductance; a unilaterally conducting decay current path connected in parallel with said switch and said power supply and poled to conduct current to said inductance in the same direction as said power supply; means for sensing the level of current in said unilateral path and providing a turn-on signal when said level of current is below a given level; and switch control means responsive to said current sensing means for shutting off said switch on a periodic basis, and for turning said switch back on in response to said turn-on signal, whereby the average current through said large inductance is determined by the duty cycle of said switch as a function of said given level of current.

Claim 4

A current source comprising: a DC power supply, a large inductance, and a switch connected between said power supply and said inductance; a unilaterally conducting decay current path connected in parallel with said switch and said power supply and poled to conduct current to said inductance in the same direction as said power supply; means for sensing the level of current in said unilateral path and providing a turn-on signal when said level of current is below a given level; and switch control means responsive to said current sensing means for shutting off said switch on a periodic basis, and for turning said switch back on in response to said turn-on signal, whereby the average current through said large inductance is determined by the duty cycle of said switch as a function of said given level of current.

Claim 5

A current source according to claim 2 wherein; said unilateral path includes a resistor; and said means providing a turn-on signal includes a reference voltage and a comparator which provides said turn-on signal in response to the voltage across said resistor being closer to zero than said reference voltage.

Claim 6

A current source according to claim 3 wherein said switch control means comprises clock means for providing a repetitive signal on a periodic basis, said signal designating a logical one over substantially all of each cycle, and designating a logical zero over a small portion of each cycle, and an AND circuit responsive to said clock means and to said comparator.

Claim 7

An energy conservative current source module adapted to supply regulated average currents to a current load, comprising: a positive DC power supply and a negative DC power supply, each of said power supplies referenced to ground; an inductor; electronic switch means connected between said positive DC power supply and one end of said inductor;

Claim 8

An energy conservative current source module adapted to supply regulated average currents to a current load, comprising: a positive DC power supply and a negative DC power supply, each of said power supplies referenced to ground; an inductor; electronic switch means connected between said positive DC power supply and one end of said inductor;

Claim 9

second electronic switch means connected from said negative DC power supply to the other end of said inductor; means for selectively conducting current from ground to said first end of said inductor and for providing a signal indication of the magnitude of current conducted thereby; means for selectively conducting current from said second end of said inductor to ground and for providing a signal indication of the magnitude of current conducted thereby; a current output adapted for connection to a current load; selectively operable means for connecting said current output to said first end of said inductor or to said other end of said inductor or for leaving said current output unconnected; a pair of selectively operable switch control means, one for each of said electronic switches, each responsive to the corresponding current magnitude indicating signal and, when operable, for commutating the operation of the related one of said electronic switches by periodically disabling said switch on a cyclic basis and again turning on said switch in response to a signal indicating a current of less than a given magnitude in the related one of said selectively conductive means; and means for selectively operating all of said selectively operable means such that current is provided through said inductor in the same direction at all times from either power supply through its related switch through one of said output connections and said load, or from either power supply through its related switch through the selectively conductive means relating to the other power supply.

Claim 10

second electronic switch means connected from said negative DC power supply to the other end of said inductor; means for selectively conducting current from ground to said first end of said inductor and for providing a signal indication of the magnitude of current conducted thereby; means for selectively conducting current from said second end of said inductor to ground and for providing a signal indication of the magnitude of current conducted thereby; a current output adapted for connection to a current load; selectively operable means for connecting said current output to said first end of said inductor or to said other end of said inductor or for leaving said current output unconnected; a pair of selectively operable switch control means, one for each of said electronic switches, each responsive to the corresponding current magnitude indicating signal and, when operable, for commutating the operation of the related one of said electronic switches by periodically disabling said switch on a cyclic basis and again turning on said switch in response to a signal indicating a current of less than a given magnitude in the related one of said selectively conductive means; and means for selectively operating all of said selectively operable means such that current is provided through said inductor in the same direction at all times from either power supply through its related switch through one of said output connections and said load, or from either power supply through its related switch through the selectively conductive means relating to the other power supply.