Abstract: The embodiments described herein provide compensation for mutual inductance in a multi-path device. In one embodiment, a device includes a multi-path integrated device. The multi-path integrated device includes a first output and a second output. The first output is configured to be coupled to a first output lead through a first bonding wire, and the second output is configured to be coupled to a second output lead through a second bonding wire. Due to their proximity, the second bonding wire has a first mutual inductance with the first bonding wire. A first compensation network is coupled to the first output, and a second compensation network is coupled to the second output. The second compensation network is configured to have a second mutual inductance with the first compensation network. The second mutual inductance at least partially cancels the effects of the first mutual inductance.

Abstract: A four-conductor MRAM device comprising an array of memory cells, each of the memory cells including a first magnetic layer, a dielectric, and a second magnetic layer; a plurality of local column sense lines wherein one is electrically connected to the first magnetic layer of the array of memory cells; a plurality of local row sense lines wherein one of the local row sense lines is electrically connected to the second magnetic layer of the array of memory cells; a plurality of global column write lines parallel to the plurality of local column sense lines; a plurality of global row write lines parallel to the plurality of local row sense lines; and wherein the plurality of local column sense lines and the plurality of local row sense lines are connected to read data from the array of memory cells and the plurality of global column write lines and the plurality of global row write lines are connected to write data to the array of memory cells.

Abstract: A method and apparatus for operating an integrated circuit in an electronic device by controlling the supply voltage to the integrated circuit (IC). A parameter of the IC is measured and used to adjust the supply voltage of the IC. The measured parameter is indicative of the effective channel mobility of the IC. One purpose of adjusting the voltage is to modify the effective channel mobility such that the individual channel currents are substantially constant over a predetermined operating temperature range of the IC. The modification of channel mobility is chosen to set the individual channel currents at levels that either maximizes operating speed, minimizes power consumption, extends the range of operating temperature, or increases the operational reliability of the IC.

Abstract: A transient ionizing radiation tolerant peripheral system for a magnetic bubble memory includes a transient ionizing radiation tolerant rotating field coil driver and a transient ionizing radiation tolerant function gate controller. Both the transient ionizing radiation tolerant rotating field coil driver and the transient ionizing radiation tolerant function gate controller have predrivers each having a bipolar switching transistor having a base, a collector and an emitter. An anti-saturation diode is connected to the collector of the bipolar switching transistor to prevent its switching speed from being reduced by being driven into saturation by excess charge carriers generated by transient ionizing radiation. A photocurrent compensator is connected to the switching transistor and draws current away from its base during exposure to transient ionizing radiation.

Abstract: An economical circuit arrangement permits disruption, during a nuclear event or single event upset, of operation in portions of a bubble memory system and in a computer connected thereto while maintaining integrity of data stored in the bubble memory. Only critical portions of the bubble support circuits are radiation hardened, and a nonstop logic circuit is provided to continue operation during a nuclear event and to conclude any memory access cycles already in progress at the beginning of the event. Spurious (ionization induced) drive pulses are distinguished from actual pulses. A nuclear event detector generates an output pulse during the event and a delay is provided in a path of the pulses in the critical circuit portions. The delay is greater than the duration of the output pulse of the detector so that pulses arriving after the detector pulse are ignored.

Abstract: In a Bloch line pair driving device comprising an inductor circuit which has first and second ends and which generates a magnetic field in a predetermined direction to drive each Bloch line pair transversely of the predetermined direction, a first switch is connected to the second end and is put in an on state to gradually increase an electric current flowing from a first voltage source through the inductor circuit in a preselected sense. Gradual growth of the magnetic field results from the gradual increase of the electric current and keeps each Bloch line pair stable at each position. A current path circuit is connected to the second end along with a second voltage source providing a second voltage different from the first voltage, and is put in an active state during an off state of the first switch. The active state of the current path circuit brings about a quick decrease of the magnetic field to propagate each Bloch line pair from each position.

Abstract: In a magnetic bubble memory device in which magnetic bubbles are propagated under influence of a rotating magnetic field, a method of controlling a stop operation of a rotating magnetic field in which magnetic field is caused to further rotate beyond the stop direction for a predetermined over-rotation angle and is then caused to return to the stop direction which is followed by the removal of the magnetic field, is presented. The over-rotation angle is in a range of 10 to 40 degrees. The invention is applicable whether bubble drive is performed using a drive current of triangular, square or trapezoidal waveform.

Abstract: A method of operating a magnetic bubble memory (of the type that has a plurality of magnetic bubbles which move in a plane in response to a magnetic drive field that rotates in said plane) includes the steps of sending respective currents through a pair of field coils to produce the rotating magnetic field; generating at least one of the currents to consist of a series of positive and negative going waveforms separated by a dwell period so that the rotation of the field temporarily stops during the dwell period; and timing the dwell period to occur when the bubbles are at predetermined locations in the memory.

Abstract: A method of controlling a magnetic bubble memory device comprising a rotating field generation coil for applying the rotating field to a magnetic pattern formed on a magnetic bubble memory chip and transferring the magnetic bubble along the magnetic pattern. A bubble memory device controlled by the method of the present invention, is capable of operating in a wider ambient temperature range by heating the chip through heat generation realized by applying a heating current to the rotating field generation coil while the magnetic bubble transfer control is not carried out.

Abstract: A series resonant drive circuit for a magnetic bubble memory includes X- and Y-coils arranged orthogonally to each other for generating a rotating magnetic field applied to a magnetic bubble memory chip, resonance capacitors each connected to a corresponding one of the X- and Y-coils for forming a series resonance circuit with the corresponding coil at a frequency of the rotating magnetic field, power supplies each connected to a corresponding one of the resonance circuits, and an inductance device connected in series with both of the resonance circuits and a capacitance device connected between the resonance circuits to compensate a mutual inductance due to the inductive coupling between the X- and Y-coils and a capacitance due to the capacitive coupling between the X- and Y-coils. Further, the temperature coefficient of the capacitance device is selected so that the temperature coefficients of the mutual inductance and capacitance between the coils can be compensated.

Abstract: The present invention provides thin film magneto-resistive readout apparatus for providing readout from magnetic memory devices such as magnetic tapes, the apparatus comprising a thin film magneto-resistive readout head element, a narrow pulse generator for applying sensing current to the readout head element in the form of trains of narrow pulses, and a signal averaging circuit connected to receive output signals from the readout head element for deriving an average output signal for the pulses in each train.

Abstract: A series resonance drive circuit for a magnetic bubble memory comprises a magnetic bubble memory chip or chips, X and Y coils arranged orthogonally to each other to form a rotating magnetic field in a plane of the chip or chips, resonance capacitors connected in series with the X and Y coils to form series resonance circuits with the X and Y coils at a frequency of the rotating magnetic field, A.C. power supplies connected to the resonance circuit, and a reactance device connected to the resonance circuits to compensate a mutual inductance due to a mutual inductive coupling between the X and Y coils and a capacitance due to a capacitive coupling between the X and Y coils. The reactance device includes a mutual inductance device, or an inductance device and a capacitance device.

Abstract: In magnetic bubble memories both linear and switched drive circuits are presently in use. The linear circuit can employ a capacitor to achieve resonance and may operate at a relatively high efficiency. However, when a linear coil drive circuit, which had been designed to operate at resonance, is operated just off resonance a substantial loss of power efficiency is observed. A switched coil drive circuit is described herein which achieves high operating power efficiency by using a capacitor in parallel with the bubble coil.

Abstract: The driving circuit for supplying current to coils for generating a rotating magnetic field is divided into a switch side circuit and a driver side circuit so as to pass current through only one of the coils. Each of the switch side circuit and the driver side circuit is constituted by a number of component circuits. The driving circuit comprises (N+M) component circuits for driving (N.times.M) coil circuits, where N represents the number of the component circuits of the switch side circuit and M that of the component circuits of the driver side circuit whereby additional coils may be driven without multiplying the number of driving circuits.

Abstract: In a field-access magnetic bubble memory X and Y coils encircle the chip for providing the rotating XY magnetic drive field when conventional drive signals are applied thereto. At least one of the coils is non-uniformly wound to provide a first predetermined magnitude of the drive field in first predetermined chip areas and a second lesser predetermined magnitude of the drive field in a second chip area. In the embodiment disclosed the chip has a dual-block replicate architecture with gates and bubble detectors requiring a relatively high drive field located in peripheral edge areas at the bottom and top of the chip. A plurality of data storage loops requiring a relatively low drive field are located in the medial portion of the chip. The outer layer of the Y coil is non-uniformly wound to provide a gap in registration with the medial area of the chip.

Abstract: A magnetic bubble driving device produces a rotating magnetic field for a magnetic bubble memory unit by using two coils wound orthogonally to each other and cylindrically around the memory unit and by using driving circuitry for driving the coils with trapezoidally-shaped currents which are 1/4 period out of phase with each other. A novel switch control mechanism is provided to produce efficient periodic coil currents by non-resonant circuit means. Each drive coil is connected to terinals T.sub.1 and T.sub.2 of a four terminal electrical bridge network (T.sub.1, T.sub.2, T.sub.3, T.sub.4) wherein each leg comprises a parallel coupling of a switch and a clamping diode and wherein an external source of potential is applied across terminals T.sub.3 and T.sub.4. Each switch opens and closes independently under the influence of a separate control signal.

Abstract: The present invention provides an improved method and apparatus for driving a magnetic bubble device, in which a d-c voltage supply and drive coils are connected to a bridge circuit consisting of four bi-directional switches, and alternating currents with steps (such as currents consisting of triangular waves or trapezoidal waves) are produced in the drive coils by suitably controlling the turn on or off of the bi-directional switches. As a result, the d-c level in the alternating current is not shifted by the variation in width of pulses which control the opening and closing of the bi-directional switches, and the magnetic bubble device is provided with a greatly improved operation margin.

Abstract: Circuitry for use in bubble memory propagation wherein field drive coils receive energy from an energy storage device (capacitor) through a plurality of selectively located and timed switches. A basic digitally controlled switching arrangement is illustrated in matrix form and, in one embodiment, one capacitor with two voltage sources and, in another embodiment, two capacitors and a single voltage source are utilized. Selective timing of the opening and closing of the switches provides a digitally controlled series of 1/2 sine wave current pulses to meet operating requirements for bubble propagation. Additional variations of the selective timing of switch opening and closings are used to elongate the start and stop pulses to provide better operating margins for these events. Field rotation in either clockwise, or counter-clockwise, or a mix of rotational senses is readily achieved under digital control.

Abstract: In a magnetic bubble memory device, an improvement to the means for providing an in-plane rotational magnetic field to advance bubbles through some appropriate, staged structural form of permalloy elements is a conductor overlay positioned so that the permalloy elements are generally oriented normally to current flow in the conductors. The conductor overlay may consist of two orthogonal groups of parallel wires or a single grid or mesh of wires with four electrical connections, one on each of four edges. The conductor overlay may be driven to produce an in-plane rotating magnetic field and the magnetic bubbles travel to or follow the induced poles in the permalloy elements just as if conventionally driven.

Abstract: A method and apparatus for producing a high frequency rotating magnetic field, in particular for domain transport stores, utilizes a rectangular pulse sequence which is fed into two parallel connected flip-flops, one of the flip-flops having an inverter connected serially in front, effecting flip-flop output signals which are phase shifted by 90.degree. which are fed via a terminal stage into respective coils of a Helmholtz coil pair, each of which coils are supplemented with capacitors to form resonant circuits.

Abstract: A field access magnetic bubble memory device including a memory chip applied with an in-plane magnetic field at need is disclosed. At a transient stop operation of the device before its interrupted state, an in-plane field is removed after it has been held for a predetermined period following the cessation of rotation thereof. The in-plane field may be increased upon the cessation of rotation thereof. At a transient start operation of the device after the interrupted state, an in-plane field having no rotation and the same direction as at the transient stop operation is applied for a predetermined period before the initiation of rotation thereof. The applied in-plane field may be increased upon the initiation of rotation thereof.

Abstract: A current drive circuit for deriving a triangular current waveform for driving an inductive load, such as the field coils of a bubble memory, comprises a series of at least four diodes connected between the positive and negative input voltage lines. A pair of switching devices, such as switching transistors, are connected in series such that each switching device is in parallel with two of the diodes. The junction between the switching devices is also connected to one output for the inductive load. The intermediate diodes are connected together and to one side of a time delay circuit, the opposite side of which is connected to the second output for the opposite side of the inductive load. A modification of the invention comprises a second diode and switching circuit connected between the time delay circuit and the second output.

Abstract: The invention relates to an arrangement for generating a magnetic supporting field for a magnetic cylindrical domain store, having a soft-magnetic plate matrix comprising at least two plane plates arranged parallel to each other at an interval, and having two bar-shaped permanent magnets situated between said plates and arranged at an interval, wherein said permanent magnets have their respective longitudinal middle axes parallel to each other and are magnetized perpendicularly thereto, and wherein at least one of which is rotatable about its longitudinal middle axis.

Abstract: Field access system for use in propagation of bubbles is disclosed. The field access system combines discrete drive elements with a continuous drive film. An example is a Permalloy overlay consisting of a continuous drive film with protruding T & I bars which function as drive elements. This overlay structure is spaced over a suitable bubble material. The drive film is in direct contact with the T & I drive elements so that exchange coupling exists between the drive film and the drive elements. Use of a continuous drive film allows for control of the drive elements by a closed flux magnetic circuit having low power consumption.