Tuyen H Trinh

US Patent:

7804657, Sep 28, 2010

Filed:

Jun 11, 2007

Appl. No.:

11/761224

Inventors:

Dennis W. Hogg - Laguna Hills CA, US
Jonas A. Goode - Lake Forest CA, US
Tuyen V. Trinh - Lake Forest CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 5/03

US Classification:

360 66

Abstract:

A method is disclosed for setting an operating bias current for a magnetoresistive (MR) element. A bias current is applied to the MR element, and a voltage across the MR element is measured corresponding to the bias current. The bias current is then adjusted in response to the bias current multiplied by a ratio of a target voltage and the measured voltage. The adjusted bias current is then applied to the MR element. In one embodiment, the bias current is adjusted until the measured voltage substantially equals the target voltage.

US Patent:

7760458, Jul 20, 2010

Filed:

Aug 12, 2008

Appl. No.:

12/190512

Inventors:

Tuyen V. Trinh - Lake Forest CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 5/03

US Classification:

360 66, 360 67, 360 46

Abstract:

A disk drive is disclosed comprising a disk including a plurality of servo sectors, a head actuated over the disk, the head for generating a read signal, and a gain control circuit for adjusting a gain of the read signal in response to a gain setting. A bias setting is initialized for the head, and the gain setting for the read signal is initialized. The read signal is processed to detect at least one of the servo sectors, and when at least one of the servo sectors is not detected, the gain setting is adjusted. The read signal is processed with the adjusted gain setting to detect at least one of the servo sectors, and when at least one of the servo sectors is not detected with the adjusted gain setting, the bias setting is adjusted in response to the adjusted gain setting.