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:
Oct. 07, 2003
Filed:
Oct. 29, 1999
Giorgio Pedrazzini, Laguna Niguel, CA (US);
STMicroelectronics, Inc., Carrollton, TX (US);
Abstract
A method and apparatus to control application of a drive current to a voice coil in a hard disk drive system modulates a periodic waveform between either a reference level and a signal associated with a stored back electromotive force (BEMF) in the voice coil. The drive current is applied to the voice coil during periods of time when the periodic waveform is modulated by the signal associated with the stored BEMF. The amplitude and duration of the drive current correspondingly decreases as the BEMF in the voice coil decreases. Thus, the voice coil is controlled based on its BEMF and is provided with decreasing power to move a head mechanism to or from a ramp assembly.