Fly height compensation using temperature and non-repeatable runouts

• US 7,511,914 B2
• Filed: 03/29/2007
• Issued: 03/31/2009
• Est. Priority Date: 03/29/2006
• Status: Expired due to Fees

• Current Assignee: Maxtor Corporation (Seagate Technology Holdings Plc)
• Original Assignee: Maxtor Corporation (Seagate Technology Holdings Plc)
• Inventors: Hiller, Bernhard, Crimi, Francis, LeFebvre, Andrew
• Primary Examiner(s): Tzeng; Fred
• Application Number:
  US11/693,415
• Publication Number:
  US 20070230017A1
• Time in Patent Office: 733 Days
• Field of Search: 360/75, 360/25, 360/99.08, 360/97.02, 384/100, 384/112, 310/90, 298/981
• US Class Current: 360/75
• CPC Class Codes: G11B 5/5565 system adaptation for compensation of variations of physical parameters, e.g. temperature
• CPC Class Codes: G11B 5/59627 Aligning for runout, eccentricity or offset compensation G11B5/5534, G11B5/59677, G11B5/59688 take precedence
• CPC Class Codes: G11B 5/6005 Specially adapted for spacing from a rotating disc using a fluid cushion
• CPC Class Codes: G11B 5/6064 using air pressure

Abstract

A controller is provided having a circuit that uses non-repeatable run-out data and temperature data to provide a compensation for a fly height of a head. A disk drive may also be provided having a head for reading data from a disk, a thermistor, and a controller for controlling a fly height of the head based on temperature data obtained from the thermistor to refine a pressure determination. A method can include estimating a first pressure by the use of non-repeatable run-out data and temperature data corresponding to a disk drive.

Claims

1. A controller, comprising:

an output terminal for operable connection to a fly height adjustment device;

a circuit that uses non-repeatable run-out and temperature data to provide a compensation signal on the output terminal, to operatively control a fly height adjustment device for controlling a fly height of a head.

2. The controller of claim 1, further comprising a thermistor, wherein the temperature data is obtained from the thermistor.

3. The controller of claim 1, wherein the circuit estimates the first pressure and provides a compensation for a fly height of a head at each startup of the controller.

4. The controller of claim 1, further comprising an inner head, the inner head located at an outer diameter of a disk when the first pressure is estimated and the non-repeatable run-out data corresponding to the inner head.

5. The controller of claim 1, wherein the circuit estimates a first pressure in providing the compensation for a fly height of a head.

6. A disk drive, comprising a controller, as recited in claim 1, wherein the first pressure is within the disk drive.

7. The disk drive of claim 6, wherein P₀ is a second pressure corresponding to the non-repeatable run-out data NRR₀ and the temperature data T₀ of a second condition of the disk drive, a proportionality constant C and slope corresponding to the disk drive, the first pressure P₁ is determined by the equation:

8. The disk drive of claim 6, wherein, P₀ is a second pressure corresponding to the non-repeatable run-out data NRR₀ corresponding to the temperature data T₀ of a second condition of the disk drive, the first pressure P₁ is determined by the equation:

9. The controller of claim 1, wherein the circuit uses an ideal gas law to determine the first pressure.

10. The controller of claim 1, wherein the circuit estimates the first pressure having the non-repeatable run-out data corresponding to only a lateral arm mode.

11. The controller of claim 1, wherein the circuit estimates the first pressure having the non-repeatable run-out data corresponding to only a suspension mode.

12. The controller of claim 1, wherein the circuit estimates the first pressure having the non-repeatable run-out data corresponding to only frequencies above 10 kHz.

13. The controller of claim 1, wherein the circuit estimates the first pressure having the non-repeatable run-out data corresponding to seeks of more than 5 tracks.

14. The controller of claim 1, wherein the circuit estimates the first pressure and calculates an altitude based on the first pressure.

15. A disk drive, comprising:

a disk having a surface provided with a plurality of tracks for storing data;

a head for reading data from the disk;

an actuator for positioning the head relative to the disk; and

a controller comprising a circuit that uses non-repeatable run-out and temperature data to provide a compensation for a fly height of the head.

16. The disk drive of claim 15, wherein the head is an outer head located at an inner diameter of a disk when the first pressure is estimated, the non-repeatable run-out data corresponding to the outer head.

17. A method, comprising:

estimating a first pressure P₁ by the use of non-repeatable run-out data NRR₁ and temperature data T₁ corresponding to a disk drive;

the method further comprising, before the act of estimating,

determining P₀, a second pressure corresponding to non-repeatable run-out data NRR₀ and temperature data T₀ of a calibration condition of the disk drive;

wherein the first pressure P₁ is determined by the equation;

18. A disk drive, comprising:

a head for reading data from a disk;

a thermistor; and

a controller for controlling a fly height of the head based on temperature data obtained from the thermistor to refine a pressure determination;

wherein the controller obtains the pressure determination based on non-repeatable run out data.

19. A method, comprising:

providing a compensation signal based on non-repeatable run-out data and temperature data; and

adjusting a fly height of a head in accordance with the compensation signal.