Fly-height management in a hard disk drive (HDD)

• US 8,098,450 B2
• Filed: 12/31/2009
• Issued: 01/17/2012
• Est. Priority Date: 12/31/2009
• Status: Expired due to Fees

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Hitachi Global Storage Technologies Netherlands BV (Western Digital Corporation)
• Inventors: Chen, Martin Yu-Wen, Contreras, John T., Kirpekar, Sujit, Knigge, Bernhard E., Baumgart, Peter
• Primary Examiner(s): Negron, Daniell L
• Assistant Examiner(s): HOLDER, REGINA NEAL
• Application Number:
  US12/651,161
• Publication Number:
  US 20110157740A1
• Time in Patent Office: 747 Days
• Field of Search: None
• US Class Current: 360/75
• 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
• CPC Class Codes: G11B 5/607 using thermal means
• CPC Class Codes: G11B 5/6076 Detecting head-disk contact

Abstract

A hard disk drive (HDD) including a first resistive temperature detector (RTD) configured to detect a temperature generated by proximity of a slider and a media. The first RTD is proximate an air bearing surface (ABS) of the slider. The HDD also includes a second RTD configured to detect at least one temperature correlated to a fly-height of the slider. The second RTD is not required to be proximate the ABS of the slider. HDD also includes a read/write integrated circuit (IC) configured to determine the fly-height of the slider based on detection of temperatures by the first RTD and the second RTD.

Claims

1. A hard disk drive (HDD) comprising:

a first resistive temperature detector (RTD) configured to detect a temperature generated by proximity of a slider and a media, wherein said first RTD is proximate an air bearing surface (ABS) of said slider;

a second RTD configured to detect at least one temperature correlated to a heating of said slider, wherein said second RTD is not required to be proximate said ABS of said slider, and

a read/write integrated circuit (IC) configured to determine an origin of an external heat source and cancel said external heat source to measure temperature changes with an origin proximate to said ABS and further configured to determine said fly-height of said slider based on detection of temperatures by said first RTD and said second RTD.

2. The HDD of claim 1, wherein said first RTD is further configured to detect a temperature generated by a real-time contact of said first RTD with said media.

3. The HDD of claim 1, wherein said read/write IC is further configured to determine said slider contact with media based on detection of temperatures by said first RTD and said second RTD.

4. The HDD of claim 1, wherein a second RTD configured to detect at least one temperature correlated to a heating of said slider comprises:

a second RTD configured to detect at least one temperature correlated to a heating of said slider, wherein said at least one temperature is selected from a group consisting of;

ambient temperature, write transducer temperature, thermal fly-height control (TFC) temperature, or self heating.

5. The HDD of claim 1, comprising:

a first current source for said first RTD; and

a second current source for said second RTD, wherein said first current source and said second current source are matched.

6. The HDD of claim 5, wherein said matching of said first current source and said second current source is calibrated to set an auto-zeroing state.

7. The HDD of claim 1, wherein said second RTD is at least 6 microns from said ABS.

8. A slider in a hard disk drive (HDD), comprising:

a first resistive temperature detector (RTD) configured to detect a temperature generated by slider contact with a media, wherein said first RTD is proximate an air bearing surface (ABS) of a slider; and

a second RTD configured to detect at least one temperature correlated to a fly-height of said slider, wherein said second RTD is not required to be proximate said ABS of said slider and wherein said first RTD and said second RTD are configured to determine an origin of an external heat source and cancel said external heat source to measure temperature changes with an origin proximate to said ABS.

9. The slider of claim 8, wherein said slider contact comprises:

real-time write-element contact.

10. The slider of claim 8, wherein a second RTD configured to detect at least one temperature correlated to a fly-height of said slider comprises:

a second RTD configured to detect at least one temperature correlated to a fly-height of said slider, wherein said at least one temperature is selected from a group consisting of;

ambient temperature, write transducer temperature or thermal fly-height control (TFC) temperature.

11. The slider of claim 8, wherein said second RTD is not required to be proximate said ABS and not required to comprise significant temperature effects of said ABS.

12. A method for fly-height management in a hard disk drive (HDD), said method comprising:

detecting a change in resistance of a first resistive temperature detector (RTD) in response to a change of temperature of said first RTD generated by slider fly-height changes over a media, wherein said first RTD is proximate an air bearing surface (ABS) of a slider;

detecting a change in resistance of a second RTD in response to a change in temperature of said second RTD, wherein said second RTD is not required to be proximate said ABS;

determining an origin of an external heat source and canceling said external heat source to measure temperature changes with an origin proximate to said ABS; and

determining a fly-height of said slider based on said change of resistance of said first RTD and said change of resistance of said second RTD.

13. The method of claim 12, wherein said determining a fly-height comprises:

determining a fly-height at a read/write integrated circuit.

14. The method of claim 12, wherein detecting a change in resistance of a first resistive temperature detector (RTD) in response to a change of temperature of said first RTD generated by slider fly-height changes over a media, comprises:

detecting a real-time first RTD contact with a media.

15. The method of claim 12, wherein detecting a change in resistance of a second RTD in response to a change in temperature of said second RTD, comprises:

detecting a change in resistance of a second RTD in response to a change in temperature of said RTD, wherein said change in temperature is in response to a group consisting of;

ambient temperature, write transducer temperature, thermal fly-height control (TFC) temperature, or self heating.

16. The method of claim 12, wherein said determining a fly-height of said slider comprises:

determining a real-time write-element fly-height.

17. The method of claim 12, comprising

connecting said first RTD and said second RTD at ground.

18. The method of claim 12, comprising:

connecting said first RTD to a first current source; and

connecting said second RTD to a second current source.

19. The method of claim 18, comprising:

matching said first current source and said second current source.

20. The method of claim 19, wherein said matching comprises:

auto zeroing calibration.