Setting an operating bias current for a magnetoresistive head using ratio of target voltage and measured voltage
AssigneeWestern Digital Technologies, Inc.
InventorsDennis W. Hogg, Jonas A. Goode, Tuyen V. Trinh
Life of this patent
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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.
Claims28
A method of setting an operating bias current for a magnetoresistive (MR) element, the method comprising:
- (a) applying a bias current to the MR element;
- (b) measuring a voltage across the MR element corresponding to the bias current;
- (c) adjusting the bias current in response to the bias current multiplied by a ratio of a target voltage and the measured voltage;
- and
- (d) applying the adjusted bias current to the MR element.
A disk drive comprising:
- a disk;
- a head actuated over the disk, the head comprising a magnetoresistive (MR) element;
- and
- control circuitry operable to set an operating bias current for the MR element by:
- (a) applying a bias current to the MR element;
- (b) measuring a voltage across the MR element corresponding to the bias current;
- (c) adjusting the bias current in response to the bias current multiplied by a ratio of a target voltage and the measured voltage;
- and
- (d) applying the adjusted bias current to the MR element.
A disk drive comprising:
- a disk;
- a head actuated over the disk, the head comprising a magnetoresistive (MR) element;
- and
- a means for setting an operating bias current for the MR element comprising:
- a means for applying a bias current to the MR element;
- a means for measuring a voltage across the MR element corresponding to the bias current;
- a means for adjusting the bias current in response to the bias current multiplied by a ratio of a target voltage and the measured voltage;
- and
- a means for determining when the measured voltage due to the adjusted bias current is substantially equal to the target voltage.
Dependencies are inferred from the claim text.