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. 26, 2002
Filed:
Nov. 09, 1998
International Business Machines Corporation, Armonk, NY (US);
Abstract
The present invention provides a retract circuit for a disk drive storage device that increases the reliability of a disk drive, and reduces the manufacturing cost. If the power supply of the disk drive is turned off, the retract circuit receives the current due to a back electromotive force from a spindle motor and clips it to a predetermined value or below, and supplies the current equal to or smaller than the predetermined value to the voice coil of a VCM. Then, the VCM drives a carriage, which swings to retract a head slider to the landing area of the disk. If the power is turned off, an FET transistor is turned on, and the current due to the back electromotive force is supplied to the voice coil via the FET transistor, a resistor, and a second FET. If the current due to the back electromotive force exceeds a predetermined value depending on the value of the resistor, two transistors are turned on. Since this turns off the second FET transistor to shut off the current supply path, the supplied current is clipped to the above predetermined value, and thus the rotational speed of the carriage is also limited.