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:
Jan. 02, 2007
Filed:
Nov. 08, 2004
Xiaoping HU, San Jose, CA (US);
Yu Sun, Fremont, CA (US);
Lin Guo, Milpitas, CA (US);
Don Brunnett, Pleasanton, CA (US);
Xiaoping Hu, San Jose, CA (US);
Yu Sun, Fremont, CA (US);
Lin Guo, Milpitas, CA (US);
Don Brunnett, Pleasanton, CA (US);
Maxtor Corporation, Scotts Valley, CA (US);
Abstract
A disk drive detects head touchdown based on a magnitude of a position error signal at a discrete frequency. The discrete frequency is one-half the disk rotation frequency or an integral multiple of the disk rotation frequency. The head is heated by turning on a heater at the discrete frequency, thereby injecting bias into a servo system that increases the PES magnitude. In addition, the servo system has a first transfer function for tracking the head during read and write operations and a second transfer function for tracking the head during head touchdown detection. The second transfer function has smaller vibration rejection than the first transfer function so that the disk drive is less sensitive to vibration during read and write operations than during head touchdown detection.