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Browse Prior Art Database

Spindle Motor Drive Method for Hard Disk Drive Using MR Heads

IP.com Disclosure Number: IPCOM000114163D
Original Publication Date: 1994-Nov-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Aoyagi, A: AUTHOR [+3]

Abstract

This article discloses a method for driving the spindle motor of HDDs. Commutation timing is written on the disk at the shipping zone. Because the MR head can read back data regardless of the disk rotation speed, this commutation timing can be read back at power-on.

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This is the abbreviated version, containing approximately 100% of the total text.

Spindle Motor Drive Method for Hard Disk Drive Using MR Heads

      This article discloses a method for driving the spindle motor
of HDDs.  Commutation timing is written on the disk at the shipping
zone.  Because the MR head can read back data regardless of the disk
rotation speed, this commutation timing can be read back at power-on.

      In sensorless spindle motors, commutation was timed according
to back EMF.  This back EMF cannot be received during power-on.
Therefore reverse rotation happens.  Also, back EMF sencing circuit
is required for this.  Using this invention, cost can be reduced by
removing this circuit and start up quality is improved.

      This invention can be used for HDDs using MR heads.
Commutation timing at start up is difficult to get.  But reading the
timing pattern on the disk will improve this.  After the motor has
accelerated to the nominal speed, the motor can be driven by
conventional servo patterns or index.