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Spindle Motor Brake Circuit

IP.com Disclosure Number: IPCOM000102318D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Enami, K: AUTHOR

Abstract

Disclosed is a circuit which makes a spindle motor stop quickly. Many hard disk files have brake means to reduce the damage of a disk surface by a contact start/stop. This circuit includes no mechanical parts, such as a relay, which work when a power supply is cut off. And also it can be used with a brushless spindle motor driver IC that can supply a large current to the spindle motor coils directly.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 90% of the total text.

Spindle Motor Brake Circuit

       Disclosed is a circuit which makes a spindle motor stop
quickly.  Many hard disk files have brake means to reduce the damage
of a disk surface by a contact start/stop.  This circuit includes no
mechanical parts, such as a relay, which work when a power supply is
cut off.  And also it can be used with a brushless spindle motor
driver IC that can supply a large current to the spindle motor coils
directly.

      The drawing shows this circuit. In the circuit, the spindle
motor driver consists of one IC module.  It has a port for a
start/stop mode change.  When this port is set at stop mode, the IC
keeps the ports for the motor coils U, V, and W at high impedance.

      When the power supply is cut off or the start/stop port is set
at the stop mode, a transistor Q3 turns off.  Then, the voltage of a
capacitor C1 makes FETs Q1 and Q2 turn on. Therefore, a current which
is generated by an electromotive force of the spindle motor coils V
and W causes a brake torque.  The motor coil U is used for a power
source of a voice coil motor control.  It makes a magnetic head go to
the home position when the power supply is cut off.

      In this operation, the voltage at the ports for the motor coil
U, V, W is not forced to be lower than ground level.  It can prevent
the spindle motor driver IC from being damaged by an unexpected large
current caused by a parasitic effect in the IC.

      In this circuit, the FET Q1 and Q...