Patents by Inventor Kenneth J. Eldredge

Kenneth J. Eldredge has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6385111
    Abstract: A Magnetic Random Access Memory (“MRAM”) device includes an array of memory cells. The device generates reference signals that can be used to determine the resistance states of each memory cell in the array, despite variations in resistance due to manufacturing tolerances and other factors such as temperature gradients across the array, electromagnetic interference and aging.
    Type: Grant
    Filed: March 14, 2001
    Date of Patent: May 7, 2002
    Assignee: Hewlett-Packard Company
    Inventors: Lung T. Tran, Kenneth J. Eldredge
  • Patent number: 6363000
    Abstract: A write circuit for a large array of memory cells of a Magnetic Random Access Memory (“MRAM”) device. The write circuit can provide a controllable, bi-directional write current to selected word and bit lines without exceeding breakdown limits of the memory cells. Additionally, the write circuit can spread out the write currents over time to reduce peak currents.
    Type: Grant
    Filed: April 5, 2001
    Date of Patent: March 26, 2002
    Assignee: Hewlett-Packard Company
    Inventors: Frederick A Perner, Kenneth J Eldredge, Lung T Tran
  • Publication number: 20010053104
    Abstract: A Magnetic Random Access Memory (“MRAM”) device includes an array of memory cells. The device generates reference signals that can be used to determine the resistance states of each memory cell in the array, despite variations in resistance due to manufacturing tolerances and other factors such as temperature gradients across the array, electromagnetic interference and aging.
    Type: Application
    Filed: March 14, 2001
    Publication date: December 20, 2001
    Inventors: Lung T. Tran, Kenneth J. Eldredge
  • Patent number: 6317376
    Abstract: A Magnetic Random Access Memory (“MRAM”) device includes an array of memory cells. The device generates reference signals that can be used to determine the resistance states of each memory cell in the array, despite variations in resistance due to manufacturing tolerances and other factors such as temperature gradients across the array, electromagnetic interference and aging.
    Type: Grant
    Filed: June 20, 2000
    Date of Patent: November 13, 2001
    Assignee: Hewlett-Packard Company
    Inventors: Lung T. Tran, Kenneth J. Eldredge
  • Publication number: 20010038548
    Abstract: A write circuit for a large array of memory cells of a Magnetic Random Access Memory (“MRAM”) device. The write circuit can provide a controllable, bi-directional write current to selected word and bit lines without exceeding breakdown limits of the memory cells. Additionally, the write circuit can spread out the write currents over time to reduce peak currents.
    Type: Application
    Filed: April 5, 2001
    Publication date: November 8, 2001
    Inventors: Frederick A. Perner, Kenneth J. Eldredge, Lung T. Tran
  • Patent number: 6262625
    Abstract: An operational amplifier includes transistors for providing a controlled current path. At least one of the transistors is in an isolated well in a substrate. Offset of the operational amplifier is corrected by applying a back gate bias voltage to at least one isolated well and changing impedance of the transistors. The proper back gate bias voltage and transistor impedance are determined by incrementally adjusting the back gate bias voltage and then incrementally adjusting the transistor impedance. Calibration values are stored in register memory. Such calibration may be performed by an auto offset calibration process.
    Type: Grant
    Filed: October 29, 1999
    Date of Patent: July 17, 2001
    Assignee: Hewlett-Packard Co
    Inventors: Frederick A. Perner, Kenneth J. Eldredge, Lung T. Tran
  • Patent number: 6256224
    Abstract: A write circuit for a large array of memory cells of a Magnetic Random Access Memory (“MRAM”) device. The write circuit can provide a controllable, bi-directional write current to selected word and bit lines without exceeding breakdown limits of the memory cells. Additionally, the write circuit can spread out the write currents over time to reduce peak currents.
    Type: Grant
    Filed: May 3, 2000
    Date of Patent: July 3, 2001
    Assignee: Hewlett-Packard Co
    Inventors: Frederick A Perner, Kenneth J Eldredge, Lung T Tran
  • Patent number: 6188615
    Abstract: Resistance of a selected memory cell in a Magnetic Random Access Memory (“MRAM”) device is sensed by a read circuit including a direct injection charge amplifier, an integrator capacitor and a digital sense amplifier. The direct injection charge amplifier supplies current to the integrator capacitor while maintaining an equipotential voltage on non-selected memory cells in the MRAM device. As the direct injection charge amplifier applies a fixed voltage to the selected memory cell, the sense amplifier measures integration time of a signal on the integrator. The signal integration time indicates whether the memory cell MRAM resistance is at a first state (R) or a second state (R+&Dgr;R).
    Type: Grant
    Filed: October 29, 1999
    Date of Patent: February 13, 2001
    Assignee: Hewlett-Packard Company
    Inventors: Frederick A. Perner, Kenneth J. Eldredge, Lung T. Tran