公开(公告)号：JPH11224402A

公开(公告)日：1999-08-17

申请号：JP31120698

申请日：1998-10-30

Applicant: ST MICROELECTRONICS INC

Inventor： AXEL ALLEGRET DE LA SJORLES

IPC: G11B5/09 ,  G11B5/00 ,  G11B5/012 ,  G11B5/48 ,  G11B19/02 ,  G11B21/00 ,  G11B33/12

Abstract: PROBLEM TO BE SOLVED: To make a preamplifier have a small-sized constitution wihtout impairing its performance by constituting it with daughter chips and a mother chip, allowing the daughter chips to amplify signals read by heads while mounting them on suspensions of an actuator and allowing the mother chip to more amplify the signals read by the heads while controlling the daughter chips. SOLUTION: A preamplifier 110 has a mother chip 112 and plural daughter chips 114a...114f. The daughter chips 114a...114f are mounted on suspensions 30a...30f and amplify signals which are read by related heads from disks 18a...18c. The mother chip 112 selects which daughter chips 114a...114f send signals to heads 40a...40f to write data on disks 18a...18c or read data from the disks 18a...18c and, moreover, controls operations of the daughter chips 114a...114f and, furthermore, amplifies signals read by the heads 40a...40f.

公开(公告)号：JP2000149206A

公开(公告)日：2000-05-30

申请号：JP31331899

申请日：1999-11-04

Applicant: ST MICROELECTRONICS INC

Inventor： PATTI GUISEPPE ,  AXEL ALLEGRET DE LA SJORLES

IPC: G11B5/39 ,  G11B5/00 ,  G11B5/012 ,  G11B5/02 ,  G11B5/03 ,  G11B5/09 ,  G11B5/40 ,  G11B5/455 ,  G11B19/02

Abstract: PROBLEM TO BE SOLVED: To make selectable a magnetioresistance head between two mode biases for biasing by enabling either of bias voltage and bias current to be supplied to the MR head by a simple pre-amplifier. SOLUTION: When a voltage bias is selected, an input signal 301 to a mode selector 302 is supplied as an output on a voltage bias line VBias, a signal indicating a desired value of bias to be used on a reading head 206 is supplied as an input to voltage DAC 308. Therefore, the level of the VBias supplied onto an output end is directly decided by a bias value input signal 301, also fed back through a loop 320, and precise desired voltage is obtained crossing the head 206. When current bias is selected, a bias input signal 301 is supplied as an output IBias on a current bias line. A reference current is used as a current source for current DAC 310, and a selected value is supplied as an output about IBias.

公开(公告)号：JP2002123903A

公开(公告)日：2002-04-26

申请号：JP2001261663

申请日：2001-08-30

Applicant: ST MICROELECTRONICS INC

Inventor： ALINI ROBERTO ,  LAM QUOCDZUNG T ,  CHEW XIAOKUN LIU ,  MACCORNACK MARK ,  BEZINQUE DAVID JOSEPH ,  LEE TEHRI ,  LE SU DANG ,  AXEL ALLEGRET DE LA SJORLES ,  DENOYER GILLES

IPC: G11B5/00 ,  G11B5/012 ,  G11B5/02 ,  G11B5/09 ,  G11B5/40

Abstract: PROBLEM TO BE SOLVED: To provide an improved method for controlling a writing head of a magnetic disk recorder. SOLUTION: In this method, the current is sunk from a 1st terminal of the writing head and also the current is substantially and simultaneously supplied to a 2nd terminal of the writing head, and consequently the voltage level of 1st normal state is presented on the 1st terminal of the writing head and the voltage level of 2nd normal state is presented on the 2nd terminal of the writing head, and these levels show the nearly middle points between the high reference voltage level and low reference voltage level. The common mode voltage of the writing head is substantially constant as to the time, accordingly.