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Title:
MOTOR DRIVE CIRCUIT AND MOTOR DRIVE CONTROL CIRCUIT
Document Type and Number:
Japanese Patent JP2005269808
Kind Code:
A
Abstract:

To perform retract operation control at high precision by preventing characteristic degradation or ASO breakage caused by the thermal loss of a power switch element at cutting off a power supply.

A first operation in which an upper side power switch element is turned on to be shorted to a power supply side and a second operation in which a lower side power switch element is turned on to be shorted to the ground potential side of a circuit are alternately performed by a brake control circuit that operates at a voltage of a counter-electromotive force that is generated by a motor coil at cutting off a power supply. A drive output stage of 3-phase DC motor rotates a magnetic disc, a VCM driver drives a voice coil motor for controlling a magnetic head, and a control circuit is provided for an output pre-driver and VCM driver. The reverse braking operation for unloading the magnetic head from the VCM driver is performed, and when the operation voltage generated at the 3-phase DC motor coil reaches a prescribed voltage, such operation as switching to GND brake for applying ground potential to both ends of the voice coil is performed a plurality of times in retract operation.


Inventors:
KAWACHI KUNIHIRO
KONOUE YASUHIKO
Application Number:
JP2004000080330
Publication Date:
September 29, 2005
Filing Date:
March 19, 2004
Export Citation:
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Assignee:
RENESAS TECH CORP
International Classes:
G11B21/12; G11B19/22; H02P3/12; H02P6/24; (IPC1-7): H02P3/12; G11B19/22; G11B21/12; H02P6/24
Attorney, Agent or Firm:
徳若 光政



 
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