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Browse Prior Art Database

Enhanced Motor Brake and Auto Landing Zone Circuit

IP.com Disclosure Number: IPCOM000122156D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Arai, K: AUTHOR [+2]

Abstract

Disclosed is a circuit for spindle motor braking and auto head parking of a hard disk drive. This circuit makes it possible to stop a spindle motor faster and to move an actuator arm to an inner or outer side of a disk when a power supply is turned off. The spindle motor is also stopped by MOTOR STOP command in this circuit. To move the actuator arm to the inner or outer side of the disk, this circuit uses kinetic energy of the spindle motor. This circuit provides an electric current of the spindle motor coil to the ground and VCM (Voice Coil Motor) when a power supply is turned off. The figure is a diagram of the brake and auto landing zone circuit. This circuit consists of the following four portions. (1) A portion which stores up electrical charge (Resistor R2, Diode D1 and Capacitor C).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 71% of the total text.

Enhanced Motor Brake and Auto Landing Zone Circuit

      Disclosed is a circuit for spindle motor braking and auto
head parking of a hard disk drive.  This circuit makes it possible to
stop a spindle motor faster and to move an actuator arm to an inner
or outer side of a disk when a power supply is turned off.  The
spindle motor is also stopped by MOTOR STOP command in this circuit.
To move the actuator arm to the inner or outer side of the disk, this
circuit uses kinetic energy of the spindle motor.  This circuit
provides an electric current of the spindle motor coil to the ground
and VCM (Voice Coil Motor) when a power supply is turned off.  The
figure is a diagram of the brake and auto landing zone circuit.  This
circuit consists of the following four portions.
      (1)  A portion which stores up electrical charge (Resistor R2,
Diode D1 and Capacitor C).  This charge is used for transistor and
FET (field-effect transistor) switching.
      (2)  A motor brake portion which consists of three FETs
(1,2,3).  These FETs act when the power supply is turned off or MOTOR
STOP signal becomes high level, then motor coil is connected each
other.  By using the character of FET whose input impedance is very
high, it becomes possible to extend the period of FET switching time.
      (3)  A transistor (a) which acts as a current limiter. The
maximum electric current which flows the VCM coil at power supply off
is described as
           I = 0.6...