Keeper Patents (Class 365/57)
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Patent number: 7613033Abstract: A magnetic storage device is provided which has significantly reduced power consumption. In the magnetic storage device, a yoke is arranged so as to circumferentially surround part of a line extending in an arbitrary direction, and a magneto-resistive element to which information can be written by utilizing a magnetic field generated by the line is arranged in the vicinity of the line. In this case, the length of the magnetic path of the yoke is set to 6 ?m or less.Type: GrantFiled: July 26, 2007Date of Patent: November 3, 2009Assignee: TDK CorporationInventors: Keiji Koga, Katsumichi Tagami, Tohru Oiakawa
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Patent number: 7336556Abstract: A non-volatile magnetic memory device is proposed, which provides sufficient magnetic shielding performance for external magnetic fields. A first magnetic shield layer 60a and a second magnetic shield layer 60b, both made of a soft magnetic metal, are formed respectively on the bottom surface of the transistor section 20, which is the mounting side of the MRAM device 10, and on the top surface of the bit line 50, which is opposite to the bottom surface of the mounting side of the MRAM device 10. On the second magnetic shield layer 60a, a passivation film 70 is formed. The magnetic flux penetrated from the external magnetic field, is suppressed below the inversion strength of the MRAM device 10, thereby improving reliability.Type: GrantFiled: July 2, 2003Date of Patent: February 26, 2008Assignee: Sony CorporationInventors: Katsumi Okayama, Kaoru Kobayashi, Makoto Motoyoshi
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Patent number: 6914805Abstract: An MRAM device comprising an array of MRAM elements, with each element having an MRAM bit influenced by a magnetic field from a current flowing through a conductor, also includes a magnetic keeper formed adjacent the conductor to advantageously alter the magnetic field. The magnetic keeper alters the magnetic field by concentrating the field within the keeper thereby reducing the extent in which fringe field exists, thus allowing the MRAM elements to be formed closer to increase the areal density of the MRAM device. Increase in magnetic field flux due to the magnetic keeper allows operation of the MRAM device with lowered power. Soft magnetic materials such as nickel iron, nickel iron cobalt, or cobalt iron may be used to form the magnetic keeper.Type: GrantFiled: August 21, 2002Date of Patent: July 5, 2005Assignee: Micron Technology, Inc.Inventors: William F. Witcraft, Lonny Berg, Alan Hurst, William Vavra, Mark Jenson
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Patent number: 5949723Abstract: For high-speed single-ended sensing of the signal from a (multi-port) SRAM cell, a configurable half-latch with 2 PFET feedback pathes is proposed, which can be set up either as a bleeder device in the system mode or as keeper devices in the test modes, controlled by a DC signal (TEST). The bleeder and keepers are attached to the bit line and gated by a small ratioed inverter serving as sense amplifier. In case of system mode, a low control signal is applied to the source of the bleeder to limit the bit line up-level to a threshold below the supply voltage Vdd. Thus, discharging the bit line when reading a `0` is fast. Reading a `1` is also fast by skewing the inverter to a PFET/NFET ratio below 1. For chip testing, the control signal is set high to enable the keepers which restore the bit line close to the supply voltage, even when large subthreshold currents try to discharge it via the unselected cells. This turns off the PFET of the inverter, thereby minimizing the DC current.Type: GrantFiled: July 30, 1998Date of Patent: September 7, 1999Assignee: International Business Machines CorporationInventors: Rainer Clemen, Herald Mielich, Jurgen Pille
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Patent number: 4547866Abstract: A non-volatile flat film memory with a symmetrical cell design having four magnetic films and full turn word line construction. The design provides flux closure during both store and read as well as providing memory storage in all films. The structure is fabricated on silicon using processes compatible with integrated circuit technology.Type: GrantFiled: May 14, 1984Date of Patent: October 15, 1985Assignee: Honeywell Inc.Inventors: Olin S. Lutes, Wayne L. Walters
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Patent number: 4455626Abstract: A radiation-hard, non-volatile, thin film planar RAM structure fabricated by silicon integrated circuit processing. This memory cell construction provides a magnetoresistive readout. A magnetoresistive film sensor is positioned in the gap of a thicker flux concentrator film. A memory film and the flux concentrator film comprise a magnetic path to the MR film.Type: GrantFiled: March 21, 1983Date of Patent: June 19, 1984Assignee: Honeywell Inc.Inventor: Olin S. Lutes
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Patent number: 4387443Abstract: A dual-conductor type current-access magnetic bubble device comprises apertured conductors on which apertured magnetic sheets having the same configuration as the corresponding conductors are disposed, whereby magnetic poles are induced on each aperture of the magnetic sheets by the in-plane magnetic field generated by the current applied to the corresponding conductors to reduce the driving current required for bubble propagation, while stable regions are formed in the substrate by the magnetic poles induced by the bubbles at the boundaries of the apertures of the magnetic sheets at the time of service interruption. The device is further provided with a magnetic rail having side walls on which magnetic poles are induced by the stray flux of the bubbles in the substrate, thereby to have stable bubble-rest regions formed in the substrate at the time of service interruption by the magnetic poles induced on the walls.Type: GrantFiled: March 23, 1981Date of Patent: June 7, 1983Assignees: Agency of Industrial Science and Technology, Ministry of International Trade and IndustryInventor: Koji Sakamoto