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:
Jul. 14, 2009
Filed:
Apr. 20, 2007
Nobuhiko Wasa, Kanagawa, JP;
Sayaka Nojiri, Kanagawa, JP;
Nobuhiko Wasa, Kanagawa, JP;
Sayaka Nojiri, Kanagawa, JP;
Hitachi Global Storage Technologies Netherlands B.V., Amsterdam, NL;
Abstract
In an embodiment of the present invention, a Hard Disk Controller Microprocessing Unit (HDC/MPU) supplies, prior to the unloading process, different currents to a VCM, with an actuator positioned in place and kept at a standstill. The HDC/MPU determines a correction factor from VCM speeds vmeas, each of which is detected at each of VCM currents Ivcm. If the determined correction factor falls outside a reference limit, the HDC/MPU determines a new circuit parameter for a VCM speed detection circuit. Further, the HDC/MPU calculates a new correction factor appropriate to the circuit parameter. The HDC/MPU and the VCM speed detection circuit control the speed of the VCM in the unloading process using the new circuit parameter and the new correction factor.