Integrated slider bias control

• US 8,049,984 B2
• Filed: 12/04/2008
• Issued: 11/01/2011
• Est. Priority Date: 12/04/2008
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: Hitachi Global Storage Technologies Netherlands BV (Western Digital Corporation)
• Inventors: Knigge, Bernhard, Franca-Neto, Luiz, Contreras, John
• Primary Examiner(s): Negron; Daniell L
• Application Number:
  US12/328,483
• Publication Number:
  US 20100142096A1
• Time in Patent Office: 1,062 Days
• Field of Search: None
• US Class Current: 360/66
• CPC Class Codes: G11B 5/6011 Control of flying height
• CPC Class Codes: G11B 5/6017 using capacitive measurement

Abstract

In a method of biasing a slider, a bias voltage is generated for biasing a slider. The bias voltage is integratedly coupled to a conductive body of the slider via an existing signal path of the slider such that the slider is biased with the bias voltage. The existing signal path is primarily used for conveying another signal to or from the slider but at least sometimes conveys the bias voltage to the conductive body in an integral fashion along with another signal.

Claims

1. A method of biasing a slider comprising:

generating a bias voltage for biasing a slider; and

integratedly coupling said bias voltage to a conductive body via a heater element signal path of said slider such that said slider is biased with said bias voltage, wherein said heater element signal path is primarily used for conveying another signal to or from said slider but at least sometimes conveys said bias voltage to said conductive body in an integral fashion along with said another signal.

2. The method as recited in claim 1, further comprising:

providing a low frequency high impedance path to ground from said conductive body; and

providing a high frequency low impedance path to ground from said conductive body such that a selected range of alternating current (AC) Radio Frequency Interference (RFI) signals from said conductive body are coupled to ground to provide RFI immunity.

3. The method as recited in claim 1, further comprising:

utilizing feedback to control a voltage level of said bias voltage on said slider.

4. The method as recited in claim 1, further comprising:

generating said bias voltage in accordance with a predetermined programmable bias voltage value.

5. An integrated slider bias control system comprising:

a slider bias voltage generator for generating a bias voltage; and

an integrated slider bias voltage output configured to integratedly couple said bias voltage to a conductive body of a slider via a heater element signal path of said slider such that said slider is biased with said bias voltage, wherein said heater element signal path is primarily used for conveying another signal to or from said slider but at least sometimes conveys said bias voltage from said slider bias voltage generator to said conductive body in an integral fashion along with said another signal.

6. The integrated slider bias control system of claim 5, wherein said slider bias voltage generator comprises:

a slider bias voltage feedback for controlling a voltage level of said bias voltage.

7. The integrated slider bias control system of claim 5, wherein said slider bias voltage generator comprises:

a transconductance amplifier.

8. The integrated slider bias control system of claim 5, wherein said integrated slider bias voltage output comprises:

a heater element output of a read-write integrated circuit (IC).

9. A hard disk drive comprising:

a disk comprising a surface for magnetic storage of data;

a slider having a head and a signal path to said head, said slider configured for moving across said surface for writing and reading of said data; and

an example integrated slider bias control system comprising;

a slider bias voltage generator for generating a bias voltage; and

an integrated slider bias voltage output configured to integratedly couple said bias voltage to a conductive body as a common mode voltage coupled to said conductive body via a signal path of said slider such that said slider is biased with said common mode voltage, wherein said signal path is primarily used for conveying another signal to or from said slider but at least sometimes conveys said common mode voltage from said slider bias voltage generator to said conductive body in an integrated fashion along with said another signal.

10. The hard disk drive of claim 9, wherein said slider bias voltage generator comprises:

a transconductance amplifier; and

a slider bias voltage feedback for controlling a voltage level of said common mode voltage.

11. The hard disk drive of claim 9, wherein said integrated slider bias voltage output comprises:

a common mode output via read+ and read−

pads of a read-write integrated circuit (IC).

12. The hard disk drive of claim 9, wherein said integrated slider bias voltage output comprises:

a common mode output via write+ and write−

pads of a read-write integrated circuit (IC).

13. The hard disk drive of claim 9, wherein said slider comprises:

a low frequency high impedance path to ground from said conductive body.

14. The hard disk drive of claim 9, wherein said slider comprises:

a high frequency low impedance path to ground from said conductive body such that that a selected range of alternating current (AC) Radio Frequency Interference (RFI) signals from said conductive body are coupled to ground to provide RFI immunity.

15. The hard disk drive of claim 9, wherein said signal path comprises two branches and said slider comprises:

matched resistive elements coupled between a slider body connection and each branch of said signal path.