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:
Mar. 23, 2004
Filed:
Dec. 21, 2001
Jeffrey A. Heydt, Oklahoma City, OK (US);
Christopher L. Hill, Apple Valley, MN (US);
Seagate Technology LLC, Scotts Valley, CA (US);
Abstract
Method and apparatus for accelerating a disc drive spindle motor to an operational velocity at which data are transferred between a host device and a disc rotated by the spindle motor. The spindle motor is initially accelerated from rest to an intermediate velocity at which sufficient back electromotive force (bemf) is generated by the rotation of the spindle motor to enable commutation circuitry of the disc drive to time the application of drive pulses to the spindle motor. The spindle motor is subsequently accelerated from the intermediate velocity to the operational velocity by applying a velocity dependent reference profile which establishes a sequence of reference levels to control the flow of current through the spindle motor during acceleration. The sequence of reference levels have different magnitudes at different velocities of the spindle motor between the intermediate velocity and the operational velocity.