Current pulse stabilizer for variable loads

Claim 2

Apparatus for stabilizing a pulse of current form a source of DC power through a variable load comprising: a transformer with a square-loop hysteresis core having a predetermined coercivity level of current required for switching it from saturation at a given polarity, said transformer having first and second windings; means including inductance in series with said second winding for driving regulated DC bias current through said second winding to saturate said core at said given polarity; switching means for coupling said source of DC power in a series circuit with said load and said first winding to drive current through said load in a given direction, the polarity of said first winding relative to said second winding being such that current through said first winding will drive said core from saturation at said given polarity toward saturation at said opposite polarity, said switching means being active to drive said current through said load for a period of time sufficient to reach said coercivity level of current and less than necessary to drive said core to saturation at said opposite polarity; and a pair of diodes connected to opposite ends of said first winding, one of said diodes being connected to said power supply and poled for forward conduction in response to induced current in said first winding when current through said load is terminated by said switching means, and the other of said diode being connected and poled to provide a return circuit for induced current in said first winding, whereby energy stored in said bias means is returned to said source of power.

Claim 3

Apparatus as defined in claim 1 wherein one end of said load remote from said first winding is coupled to circuit ground, said switching means comprises a series switch coupling said source of power to said first winding at an end thereof remote from said load said source of power is connected between said series switch and circuit ground, said one of said diodes is connected between circuit ground and said first winding at an end thereof remote from said load, and the other of said diodes is connected between said power source and said first winding at an end thereof remote from said power source.

Claim 4

A current pulse stabilizer for a variable load comprising: means DC coupling one end of said load to circuit ground; a first transformer with a square-loop hysteresis core having first and second windings; a choke coil connected in series with said second winding; a source of regulated DC bias current connected in series with said choke coil and said second winding for driving current through said second winding in a direction for biasing said core beyond a saturation point of a given polarity; a source of DC power having one terminal at a given polarity and another terminal connected to circuit ground; switching means for DC coupling said one terminal of said power supply to said load through said first winding to drive current in a given direction through said load to circuit ground, the polarity of said first winding relative to said second winding being such that current through said first winding will cancel flux in said core produced by bias current in said second winding, said switching means being active to produce said current pulse for a period of time less than necessary to drive said core through said saturation point of said given polarity to a saturation point of opposite polarity; and a pair of diodes connected to opposite ends of said first winding, one of said diodes being connected between circuit ground and one terminal of said first winding adjacent said source of power, and the other of said diodes being connected between said one terminal of said source of power and the other terminal of said first winding adjacent said load, said pair of diodes being poled for forward conduction in response to induced current from said second winding when current through said load is terminated by said switching means, whereby energy stored in said coil while current is driven through said load is returned to said source of power.

Claim 5

A current pulse stabilizer for a variable load comprising: means DC coupling one end of said load to circuit ground; a first transformer with a square-loop hysteresis core having first and second windings; a choke coil connected in series with said second winding; a source of regulated DC bias current connected in series with said choke coil and said second winding for driving current through said second winding in a direction for biasing said core beyond a saturation point of a given polarity; a source of DC power having one terminal at a given polarity and another terminal connected to circuit ground; switching means for DC coupling said one terminal of said power supply to said load through said first winding to drive current in a given direction through said load to circuit ground, the polarity of said first winding relative to said second winding being such that current through said first winding will cancel flux in said core produced by bias current in said second winding, said switching means being active to produce said current pulse for a period of time less than necessary to drive said core through said saturation point of said given polarity to a saturation point of opposite polarity; and a pair of diodes connected to opposite ends of said first winding, one of said diodes being connected between circuit ground and one terminal of said first winding adjacent said source of power, and the other of said diodes being connected between said one terminal of said source of power and the other terminal of said first winding adjacent said load, said pair of diodes being poled for forward conduction in response to induced current from said second winding when current through said load is terminated by said switching means, whereby energy stored in said coil while current is driven through said load is returned to said source of power.

Claim 6

A current pulse stabilizer as defined in claim 3 wherein said means DC coupling one end of said load to circuit ground includes a source of power having one terminal connected to circuit ground and a second terminal at a polarity opposite said given polarity, and said switching means comprises two series switches, one at each end of said first winding, whereby one switch remote from said load may be activated with the other switch during the current pulse rise time to provide a drive voltage equal to the sum of potentials of said sources of power at opposite ends of said load, and then deactivated to provide a drive voltage for sustaining current through said load equal to the potential of said source of power at said one end of said load.

Claim 7

A current pulse stabilizer as defined in claim 4 wherein said load is a core drive line of a magnetic core through which current must be driven in either direction, further including: a second transformer with a square-loop hysteresis core having first and second windings, said second winding being connected in series with said choke coil to receive said bias current; a separately controlled switch at each end of said first winding of said second transformer coupling said first winding in series with said load at the end thereof opposite said one end, and in series with said source of power of opposite polarity for operation in substantially the same manner as corresponding switches connected to said first winding of said first transformer, the polarity of said first winding of said second transformer being such that current therethrough will cancel flux in said core of said second transformer produced by bias current in said second winding of said second transformer for current through said load in a direction opposite said given direction; a second pair of diodes, one of said second pair of diodes connected between circuit ground and said first winding of said second transformer at the end thereof remote from said load, and the other of said second pair of diodes connected between said source of power of opposite polarity and said first winding of said second transformer at the end thereof next to said load, said second pair of diodes being poled for forward conduction in response to induced current from said second winding of said second transformer when current through said load and said first winding of said second transformer is terminated, whereby energy stored in said coil, while current is driven through said load in a direction opposite said given direction, is returned to said power supply of opposite polarity; a second source of power having one terminal of a polarity opposite said given polarity and another terminal connected to circuit ground; and means for selectively coupling said load at the end thereof remote from said first and second transformers to one power source terminal of said given polarity when said switches connected to said first transformer are activated and, to said one power source terminal of opposite polarity when said switches connected to said second transformer are activated.

Claim 8

In combination: a load through which a fast-rise current pulse is to be driven with a stable amplitude for different values of load impedance, said load being DC coupled at one end to circuit ground; means DC coupling one end of said load to circuit ground; a first transformer with a square-loop hysteresis core having first and second windings; means including a choke coil for driving regulated DC bias current through said second winding in a direction for biasing said core beyond a saturation point of a given polarity; a source of DC power having one terminal at a given polarity and another terminal connected to circuit ground; first switching means at one end of said first winding for DC coupling said first winding in series with said load; second switching means connected to said one terminal of said source of power for DC coupling said source of power to said first winding to drive current in a given direction through said load to circuit ground, the polarity of said first winding relative to said second winding being such that current through said first winding will cancel flux in said core produced by bias current in said second winding, said first and second switching means being active for a period of time less than necessary to drive said core through said saturation point of said given polarity to a saturation point of opposite polarity; and a first diode connected between circuit ground and said one end of said first winding, and a second diode connected between said one terminal of said source of power and said first winding at an end thereof opposite said one end, said first and second diodes being poled for forward conduction in response to induced current from said second winding when current through said load is terminated by said first and second switching means, whereby energy stored in said coil while current is driven through said load is returned to said source of power.

Claim 9

In combination: a load through which a fast-rise current pulse is to be driven with a stable amplitude for different values of load impedance, said load being DC coupled at one end to circuit ground; means DC coupling one end of said load to circuit ground; a first transformer with a square-loop hysteresis core having first and second windings; means including a choke coil for driving regulated DC bias current through said second winding in a direction for biasing said core beyond a saturation point of a given polarity; a source of DC power having one terminal at a given polarity and another terminal connected to circuit ground; first switching means at one end of said first winding for DC coupling said first winding in series with said load; second switching means connected to said one terminal of said source of power for DC coupling said source of power to said first winding to drive current in a given direction through said load to circuit ground, the polarity of said first winding relative to said second winding being such that current through said first winding will cancel flux in said core produced by bias current in said second winding, said first and second switching means being active for a period of time less than necessary to drive said core through said saturation point of said given polarity to a saturation point of opposite polarity; and a first diode connected between circuit ground and said one end of said first winding, and a second diode connected between said one terminal of said source of power and said first winding at an end thereof opposite said one end, said first and second diodes being poled for forward conduction in response to induced current from said second winding when current through said load is terminated by said first and second switching means, whereby energy stored in said coil while current is driven through said load is returned to said source of power.

Claim 10

A combination as defined in claim 6 wherein said means coupling said one end of said load to said circuit ground includes a second source of power having one terminal of a polarity opposite said given polarity DC coupled to said load and another terminal connected to circuit ground, and wherein said first and second switching means are separately controlled, whereby both switching means may be activated initially to provide a drive voltage for current through said load equal to the sum of output voltages from said sources of power coupled to opposite ends of said load, and said first switching means at said one end of said first transformer winding may be deactivated at the end of the rise time of current through said load to reduce the drive voltage to that coupled to the end of said first transformer winding through said load until the end of the current pulse, at which time said second switching means may be deactivated.

Claim 11

A combination as defined in claim 7 wherein said load is a core drive line of a magnetic core through which current must be driven in either direction, further including: a second transformer with a square-loop hysteresis core having a first winding and a second winding, said second winding being connected in series with said choke coil and said second winding of said first transfoRmer to receive bias current; separately controlled switching means at each end of said first winding of said second transformer coupling said first winding in series with said load at the end thereof opposite said one end, and in series with said source of power of opposite polarity for operation in substantially the same manner as corresponding switching means connected to said first winding of said first transformer, the polarity of said first winding of said first transformer being such that current therethrough will cancel flux in said core of said second transformer produced by bias current in said second winding of said second transformer for current through said load in a direction opposite said given direction; a third diode connected between circuit ground and said first winding of said second transformer at the end thereof remote from said load, and a fourth diode connected between said source of power of opposite polarity and said first winding of said second transformer at the end thereof next to said load, said third and fourth diodes being poled for forward conduction in response to induced current from said second winding of said second transformer when current through said load and said first winding of said second transformer is terminated, whereby energy stored in said coil, while current is driven through said load in a direction opposite said given direction, is returned to said power supply of opposite polarity; and a means for coupling said load at the end thereof remote from said first and second transformers to said one terminal of said source of power of said given polarity when said separately controlled switching means connected to said second transformer are activated, and to said one terminal of said second source of power when said first and second switching means connected to said first transformer are actuated.

Claim 12

In a bipolar current drive system for bit drive lines of a magnetic core memory wherein said drive lines are divided into two groups with current in lines of one group opposite current in lines of the other group, and wherein a given line in one group is paired with a given line in the other, a pair of current pulse stabilizers comprising: first and second transformers, each with a square-loop hysteresis core having a predetermined coercivity level of current required for switching it from saturation at a given polarity to saturation at an opposite polarity; bias means including inductance in series with said second winding for driving regulated DC bias current through the second winding of each transformer in series to saturate each transformer at said given polarity; negative and positive sources of DC power, said negative source having one terminal connected to circuit ground said positive source having one terminal connected to circuit ground, whereby negative and positive current drive potentials are provided with respect to circuit ground; first and second switching means for coupling said first and second sources of power in series circuits with respective ones of said paired lines and said first winding of said first and second transformers, respectively, to drive current through said paired lines in opposite directions, the polarity of said first winding relative to said second winding in each of said first and second transformers being such that current through said first winding will drive said core from saturation at said given polarity toward saturation at said opposite polarity, said first and second switching means being active to drive said currents through said given lines for a period of time sufficient to reach said coercivity level of current and less than necessary to drive said core to saturation at said opposite polarity; and two pairs of diodes, one pair for each transformer, one diode of a given pair being connected between said first winding of a given transformer at the end remote from the source of power to which said first winding is connected, and the other diode of said given pair being connected between said first winding of said given transformer at the end adjacent to said source of power to which said first winding is connected and circuit ground, each pair of diodes being poled for forward conduction in response to induced current in said first winding to which connected when said first and second switching means terminate currents through said lines, whereby energy stored in said bias means is returned to said sources of power in a substantially balanced manner from said inductance in said bias means.

Claim 13

In a bipolar current drive system for bit drive lines of a magnetic core memory wherein said drive lines are divided into two groups with current in lines of one group opposite current in lines of the other group, and wherein a given line in one group is paired with a given line in the other, a pair of current pulse stabilizers comprising: first and second transformers, each with a square-loop hysteresis core having a predetermined coercivity level of current required for switching it from saturation at a given polarity to saturation at an opposite polarity; bias means including inductance in series with said second winding for driving regulated DC bias current through the second winding of each transformer in series to saturate each transformer at said given polarity; negative and positive sources of DC power, said negative source having one terminal connected to circuit ground said positive source having one terminal connected to circuit ground, whereby negative and positive current drive potentials are provided with respect to circuit ground; first and second switching means for coupling said first and second sources of power in series circuits with respective ones of said paired lines and said first winding of said first and second transformers, respectively, to drive current through said paired lines in opposite directions, the polarity of said first winding relative to said second winding in each of said first and second transformers being such that current through said first winding will drive said core from saturation at said given polarity toward saturation at said opposite polarity, said first and second switching means being active to drive said currents through said given lines for a period of time sufficient to reach said coercivity level of current and less than necessary to drive said core to saturation at said opposite polarity; and two pairs of diodes, one pair for each transformer, one diode of a given pair being connected between said first winding of a given transformer at the end remote from the source of power to which said first winding is connected, and the other diode of said given pair being connected between said first winding of said given transformer at the end adjacent to said source of power to which said first winding is connected and circuit ground, each pair of diodes being poled for forward conduction in response to induced current in said first winding to which connected when said first and second switching means terminate currents through said lines, whereby energy stored in said bias means is returned to said sources of power in a substantially balanced manner from said inductance in said bias means.

Claim 14

The combination as defined in claim 9 wherein one end of each line of said pair remote from said transformers is coupled to circuit ground by respective first and second switching means and said positive and negative sources of power, and a given one of said first and second switching means comprises a first series switch at one end of said first winding of a transformer coupled to a source of power and a second series switch at the other end of said first winding of a transformer coupled to a line, whereby said first and second switches of a given switching means may be activated simultaneously to initiate current with a drive voltage equal to twice the potential of a given power source, and said first switch may be deactivated before said second switch to maintain drive current with a drive voltage equal to the potential of a given power source, said drive current being maintained through one of said paired diodes connected to circuit ground, whereby a tight-controlled pulsed current loop is maintained from one to the other of said paired lines through said diodes connected to circuit ground.

Claim 15

The combination as defined in claim 10 further comprising a second pair of current pulse stabilizers for said paired lines identical to said first pair but oppositely connected to said paired lines such that simultaneous currents in opposite directions are reversed from directions of currents produced by said first pair of current stabilizers when said second pair of current stabilizers are activated by first and second switching means of said second pair.

Claim 16

The combination as defined in claim 11 wherein all second windings of all transformers are connected in a single-series circuit of said bias means.