The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 24, 2006
Filed:
Sep. 30, 2003
Yosuke Hamada, Fujisawa, JP;
Kazuyuki Date, Fujisawa, JP;
Yosuke Hamada, Fujisawa, JP;
Kazuyuki Date, Fujisawa, JP;
Hitachi Global Storage Technologies Japan, Ltd., Odawara, JP;
Abstract
A disk drive comprises a controller () that calculates a drive signal for positioning a head at a desired track on the basis of a desired track-position signal and a measured head-position signal, and a drive circuit for driving a voice-coil motor. The drive circuit includes a current feedback amplifier () and a voltage feedback amplifier (), which can be selectively used. The controller () is provided with a speed limiter for determining a maximum speed limiting the speed of a head. The voltage feedback amplifier of the drive circuit is used when the head-position signal is unstable or otherwise malfunctioning, and the current feedback amplifier of the drive circuit is used when the head-position signal is normal.