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:
May. 28, 2002
Filed:
Aug. 11, 1999
Hidetoshi Kawachi, Nishitama-gun, JP;
Koji Osafune, Ome, JP;
Kabushiki Kaisha Toshiba, , JP;
Abstract
Disclosed is a head loading/unloading type disk drive of retracting a head to a ramp by a reserve power supply upon power down of a main power supply. An unloading control system drives a VCM using a low-level voltage from the reserve power supply until the head reaches the ramp immediately upon power down of the main power supply. After the head reaches the ramp, the system applies a high-level voltage from the reserve power supply. The reserve power supply is made up of a rectifier for converting the back EMF of an SPM into a DC voltage. When a retract circuit detects power down of the main power supply, the DC voltage from the rectifier is limited to a low-level constant voltage by a constant voltage circuit, and applied to the VCM. When a ramp collision determining circuit determines collision of the head against the ramp, it controls the voltage applied to the VCM from the low-level voltage to a high-level voltage.