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    BIAS IMPARTING CIRCUIT FOR MAGNETORESISTIVE SENSOR
    1.
    发明专利
    BIAS IMPARTING CIRCUIT FOR MAGNETORESISTIVE SENSOR 失效

    公开(公告)号：JPH10124807A

    公开(公告)日：1998-05-15

    申请号：JP24133497

    申请日：1997-09-05

    Applicant: IBM

    Inventor： KLAASSEN KLAAS BEREND ,  VAN PEPPEN JACOBUS

    IPC: G01R33/035 ,  G01R33/09 ,  G11B5/00 ,  G11B5/012 ,  G11B5/02 ,  G11B5/03 ,  G11B5/39 ,  G11B5/40 ,  G11B5/48 ,  G11B5/596 ,  G11B33/12

    Abstract: PROBLEM TO BE SOLVED: To compensate change in the physical characteristic of a magnetoresistive(MR) sensor and the physical tolerance during the manufacture by providing a bias circuit for generating a bias current and voltage for an MR converter. SOLUTION: A bias circuit 900 for imparting a specific bias power to an MR head is provided with a current sink formed by an amplifier 901, transistor 902 and a resistor 903. The output current of the sink is proportional to a head voltage VH, with the voltage VH value at both ends of the MR head (RH) connected between both ends of the sink, controlling the value of the collector current of the transistor 902. In the method of specific MR sensor/bias voltage, only the resistance RS of the entire MR head resistance RH is given a bias using a specific voltage. A specific current density JS is attained in the sensor other than the specific temperature rise of the sensor in the ambient temperature or above. It is also implemented by compensating non-sensor resistance, lead resistance and front-lead resistance in the head resistance.

    DEVICE AND METHOD FOR CORRECTING MAGNETO-RESISTANCE ASYMMETRY
    2.
    发明专利
    DEVICE AND METHOD FOR CORRECTING MAGNETO-RESISTANCE ASYMMETRY 审中-公开

    公开(公告)号：JP2002197602A

    公开(公告)日：2002-07-12

    申请号：JP2001332187

    申请日：2001-10-30

    Applicant: IBM

    Inventor： BHAUMIK JAYDIP ,  KERTIS ROBERT ANDREW ,  KLAASSEN KLAAS BEREND ,  RAYMOND ALLAN RICHIETTA ,  VAN PEPPEN JACOBUS CORNELIS LE

    IPC: G11B5/09 ,  G11B5/00 ,  G11B5/02 ,  G11B5/39

    Abstract: PROBLEM TO BE SOLVED: To provide a correction device for the magneto-resistance asymmetry and its method so that an asymmetric pulse from a magneto-resistance head is easily and efficiently corrected. SOLUTION: The device is provided with a shift circuit, 1st gain circuit, 2nd gain circuit and 3rd gain circuit. In the shift circuit, a shifted recording signal is produced by adding or dividing the shifted value with respect to a reading signal in accordance with the polarity of asymmetry. The reading signal, the shifted reading signal and the shifted value are produced by the shift circuit. The reading signal, the shifted reading signal and the shifted value are respectively received by the 1st, 2nd and 3rd gain circuits, and outputs amplified in accordance with each control signal are respectively produced. The reading signal is received by a control means to detect the polarity of the optional asymmetry of the reading signal, then a polarity signal is given to the shift circuit in accordance with the required correction amount, and also the respective control signals are given to the 1st, 2nd and 3rd gain circuits.

    WIDE BAND READ OF MAGNETORESISTIVE HEAD FOR DATA STORAGE APPARATUS
    3.
    发明专利
    WIDE BAND READ OF MAGNETORESISTIVE HEAD FOR DATA STORAGE APPARATUS 失效

    公开(公告)号：JP2000285403A

    公开(公告)日：2000-10-13

    申请号：JP2000068582

    申请日：2000-03-13

    Applicant: IBM

    Inventor： KLAASSEN KLAAS BEREND ,  JACOBUS CORNELIS L

    IPC: G11B5/00 ,  G11B5/012 ,  G11B5/02 ,  G11B5/39 ,  H03F1/42 ,  H03F3/45 ,  H03H11/28

    Abstract: PROBLEM TO BE SOLVED: To enlarge a channel bandwidth without deteriorating a signal-to-noise ratio performance by forming an input impedance of a read back amplifier of a combination of impedances related to a gain stage and an active terminal, and making the impedance almost equal to a characteristic impedance of a mutual connection part. SOLUTION: In a current detection read back amplifier constitution 300, an MR element Rmr present at a head 301 is connected to a current detection read back amplifier 302 via a mutual connection part 303. A characteristic impedance of the mutual connection part 303 satisfies Z0=R0, and an input impedance Zin is raised to a level of 2O-RO by positive feedback. When an input impedance of the read back amplifier is electronically raised to agree with the characteristic impedance of the mutual connection part 303, a signal-to-noise ratio performance of the channel does not change. A total bandwidth of a channel front end is determined only by an electronics bandwidth.

    6.
    发明专利
    未知

    公开(公告)号：DE69317084D1

    公开(公告)日：1998-04-02

    申请号：DE69317084

    申请日：1993-07-14

    Applicant: IBM

    Inventor： JOVE STEPHEN ALAN ,  KLAASSEN KLAAS BEREND ,  VAN PEPPEN JACOBUS CORNELIS LE

    IPC: G11B5/00 ,  G11B5/012 ,  G11B5/02 ,  G11B5/11 ,  G11B5/39 ,  G11B5/40 ,  G11B5/55 ,  G11B19/02 ,  G11B19/04 ,  G11B23/50 ,  G11B33/00 ,  G11B33/14 ,  H03F3/04 ,  H03F3/195 ,  G11B20/24 ,  G01R33/06

    Abstract: Low noise, low power, low voltage amplifier circuits with a single ended input having no common mode rejection for concurrently biasing and amplifying signals generated by magnetoresistive (MR) elements in a disk file. The amplifier circuits comprise a single (grounded) supply voltage source. One terminal of each MR element and the conductive substrate of each MR element and the conductive substrate of each disk in the disk file are grounded to minimize transient conductive asperity currents. The head/disk assembly of the disk file is completely enclosed by a highly conductive electrostatically shielded metallic enclosure that.. operates as a Faraday cage and isolates leads connecting the MR elements with the amplifier circuit from large, fast rise/fall time voltage transients.

    7.
    发明专利
    未知

    公开(公告)号：DE69120600T2

    公开(公告)日：1997-01-23

    申请号：DE69120600

    申请日：1991-04-26

    Applicant: IBM

    Inventor： KLAASSEN KLAAS BEREND ,  VAN PEPPEN JACOBUS CORNELIS LE

    IPC: G11B5/09 ,  G11B5/465 ,  G11B5/55 ,  G11B19/04 ,  G11B5/03

    Abstract: A magnetic recording system includes a current- tapering circuit which gradually reduces the WRITE current in a magnetic recording head to zero over a time interval on the same order of magnitude as the characteristic relaxation time of the domain patterns in the magnetic recording head, rather than abruptly. Specific embodiments of the current-tapering circuit create a down-sloping ramp, a decaying exponential curve, and a high-frequency burst. The resultant magnetic recording system has reduced Barkhausen noise and reproducible READ performance as well as improved READ sensitivity following a WRITE operation.

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