Disk drive employing power source modulation for reducing power consumption

• US 6,285,521 B1
• Filed: 03/25/1999
• Issued: 09/04/2001
• Est. Priority Date: 03/25/1999
• Status: Expired due to Term

• Current Assignee: Western Digital Corporation
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Hussein, Hakam D.
• Primary Examiner(s): Sniezek, Andrew L.
• Application Number:
  US09/276,255
• Time in Patent Office: 894 Days
• Field of Search: 360/73.03, 360/73.01, 360/69, 360/77.02, 360/77.08, 360/61
• US Class Current: 360/73.03
• CPC Class Codes: G11B 15/46 Controlling, regulating, or indicating speed dependent on position of tape in reserve, loop G11B15/56, G11B15/58
• CPC Class Codes: G11B 5/59655 Sector, sample or burst servo format

Abstract

A disk drive includes a disk having data tracks including servo sectors and data regions disposed between the servo sectors. A transducer head writes data to and reads data from the data regions and reads servo information from the servo sectors. A spindle motor rotates the disk. A spindle motor driver provides current to the spindle motor. A track-following controller is responsive to the servo information for causing the transducer head to remain on track. A microprocessor performs a power-saving idle operation of causing the spindle motor driver to sequentially (1) provide no current to the spindle motor for at least one disk revolution and (2) provide current to the spindle motor for at least one disk revolution. The power-saving idle operation is performed while the track-following controller causes the transducer head to remain on track for multiple disk revolutions. The power-saving idle operation is typically performed during an idle state of the disk drive to reduce power consumed by the disk drive while permitting fast recovery from the idle state to read and write operations.

Claims

1. A disk drive comprising:

a disk including a recording surface having a plurality of data tracks, each data track having servo sectors and data regions disposed between the servo sectors, the servo sectors including servo information;

transducer means for writing and reading from the data regions and reading servo information from the servo sectors;

a spindle motor coupled to the disk to rotate the disk;

a spindle motor driver for selectively providing current to the spindle motor;

track-following control means being responsive to the servo information for causing the transducer means to remain on track; and

programmable means for performing a power-saving idle operation of causing the spindle motor driver to sequentially (1) provide no current to the spindle motor for at least one disk revolution and (2) provide current to the spindle motor for at least one disk revolution, the power-saving idle operation being performed while the track-following control means causes the transducer means to remain on track for multiple disk revolutions.

2. The disk drive of claim 1 wherein the spindle motor rotates the disk at a variable spin-rate and the disk drive further comprises:

means for producing a speed-indicating signal representing the variable spin-rate of the disk; and

wherein the programmable means reads the speed-indicating signal to determine the variable spin-rate of the disk and performs the operation of causing the spindle motor driver to sequentially (1) provide no current to the spindle motor until the variable spin-rate is approximately equal to a selected minimum spin-rate and (2) provide current to the spindle motor until the variable spin-rate is approximately equal to a selected maximum spin-rate.

3. The disk drive of claim 2 wherein the variable spin-rate of the disk is substantially at a selected target spin-rate when the transducer means writes data to the data regions and the selected maximum spin-rate is approximately equal to the selected target spin-rate.

4. The disk drive of claim 1 wherein the programmable means performs the operation of causing the spindle motor driver to sequentially (1) provide no current to the spindle motor for a first selected interval of time and (2) provide current to the spindle motor for a second selected interval of time.

5. The disk drive of claim 1 wherein the wherein the programmable means performs the operation of causing the spindle motor driver to sequentially (1) provide no current to the spindle motor to cause the spindle motor to coast for at least one disk revolution and (2) provide current to the spindle motor to increase the spin-rate of the disk for at least one disk revolution.

6. The disk drive of claim 1 wherein the spindle motor rotates the disk at a variable spin-rate and the disk drive further comprises:

means for indicating a busy state while the transducer means is writing data to or reading data from the data regions and for indicating an idle state while the transducer means is not writing data to or reading data from the data regions;

wherein the programmable means is responsive to the busy state to control the spindle motor driver to provide current to the spindle motor to maintain the variable spin-rate of the disk substantially at a busy target spin-rate; and

wherein the programmable means is responsive to the idle state to control the spindle motor driver to sequentially (1) provide no current to the spindle motor for at least one disk revolution and (2) provide current to the spindle motor for at least one disk revolution to reduce power consumed by the disk drive during the idle state while maintaining the variable spin-rate of the disk above a selected minimum spin-rate.

7. The disk drive of claim 6 wherein the transducer means reads data from the data regions immediately after the idle state while the programmable means controls the spindle motor driver to increase the variable spin-rate to the busy target spin-rate.

8. The disk drive of claim 6 wherein the transducer means does not write data to the data regions after the idle state until the programmable means controls the spindle motor driver to increase the variable spin-rate to the busy target spin-rate.

9. The disk drive of claim 1 wherein the servo information includes a servo sync mark field and wherein the track following control means includes timing means for enabling a timing window for the transducer means to read and detect the servo sync mark field, wherein the timing means responds to the detection of a first servo sync mark field from a first servo sector of a target data track to enable a timing window for the transducer means to read and detect a second servo sync mark field from a second servo sector in the target data track.

10. The disk drive of claim 9 wherein the programmable means causes the timing means to increase the timing window to permit the transducer means to remain on track for multiple disk revolutions while causing the spindle motor driver to cyclically (1) provide no current to the spindle motor for at least one disk revolution and (2) provide current to the spindle motor for at least one disk revolution.

11. The disk drive of claim 9 wherein the servo information further includes phase lock oscillator information and the timing means enables the timing window based on the phase lock oscillator information.

12. The disk drive of claim 9 wherein the servo information further includes servo burst information and wherein the transducer means provides a sampled position error signal indicating off-track position and wherein the track following control means demodulates the sampled position error signal for causing the transducer means to remain on track.

13. A method of operating a disk drive comprising a disk including a recording surface having a plurality of data tracks, each data track having servo sectors and data regions disposed between the servo sectors, the servo sectors including servo information, the disk drive including transducer means for writing and reading from the data regions and reading servo information from the servo sectors, a spindle motor coupled to the disk to rotate the disk, and a spindle motor driver for selectively providing current to the spindle motor, the method comprising the steps of:

(a) maintaining the transducer means on track for multiple disk revolutions; and

(b) while performing step a, sequentially (1) providing no current to the spindle motor for at least one disk revolution and (2) providing current to the spindle motor for at least one disk revolution.

14. The method of claim 13 wherein the spindle motor rotates the disk at a variable spin-rate and the method further comprises the steps of:

producing a speed-indicating signal representing the variable spin-rate of the disk; and

cyclically reading the speed-indicating signal to determine the variable spin-rate of the disk; and

in step b, sequentially (1) providing no current to the spindle motor until the variable spin-rate is approximately equal to a selected minimum spin-rate and (2) providing current to the spindle motor until the variable spin-rate is approximately equal to a selected maximum spin-rate.

15. The method of claim 14 wherein the variable spin-rate of the disk is substantially at a selected target spin-rate when the transducer means writes data to the data regions and the selected maximum spin-rate is approximately equal to the selected target spin-rate.

16. The method of claim 13 wherein step b comprises sequentially (1) supplying no current to the spindle motor for a first selected interval of time and (2) supplying current to the spindle motor for a second selected interval of time.

17. The method of claim 13 wherein step b comprises sequentially (1) providing no current to the spindle motor to cause the spindle motor to coast for at least one disk revolution and (2) providing current to the spindle motor to increase the spin-rate of the disk for at least one disk revolution.

18. The method of claim 13 wherein the spindle motor rotates the disk at a variable spin-rate and the method further comprises the steps of:

indicating a busy state while the transducer means is writing data to or reading data from the data regions;

indicating an idle state while the transducer means is not writing data to or reading data from the data regions;

responding to the busy state to control the spindle motor driver to provide current to the spindle motor to maintain the variable spin-rate of the disk substantially at a busy target spin-rate; and

responding to the idle state to control the spindle motor driver to sequentially (1) provide no current to the spindle motor for at least one disk revolution and (2) provide current to the spindle motor for at least one disk revolution to reduce power consumed by the disk drive during the idle state while maintaining the variable spin-rate of the disk above a selected minimum spin-rate.

19. The method of claim 18 further comprising the step of:

increasing the variable spin-rate to the busy target spin-rate while the transducer means reads data from the data regions immediately after the idle state.

20. The method of claim 18 further comprising the step of:

increasing the variable spin-rate to the busy target spin-rate after the idle state prior to the transducer means writing data to the data regions.

21. The method of claim 13 wherein the servo information includes a servo sync mark field and wherein step a comprises enabling a timing window for the transducer means to read and detect the servo sync mark field, wherein the enabling step includes responding to the detection of a first servo sync mark field from a first servo sector of a target data track to enable a timing window for the transducer means to read and detect a second servo sync mark field from a second servo sector in the target data track.

22. The method of claim 21 wherein step a further comprises increasing the timing window to permit the transducer means to remain on track for multiple disk revolutions while performing step b.

23. The method of claim 21 wherein the servo information further includes phase lock oscillator information and wherein the enabling step includes enabling the timing window based on the phase lock oscillator information.

24. The method of claim 21 wherein the servo information further includes servo burst information and the transducer means provides a sampled position error sig indicating off-track position, and wherein step a further comprises demodulating the sampled position error signal for maintaining the transducer means on track.

25. A disk drive comprising:

a disk including a recording surface having a plurality of data tracks, each data track having servo sectors and data regions disposed between the servo sectors, the servo sectors including servo information;

transducer means for writing and reading from the data regions and reading servo information from the servo sectors;

a spindle motor having a plurality of windings, the spindle motor coupled to the disk to rotate the disk;

a spindle motor driver having switching elements coupled to the plurality of windings for selectively providing current to the spindle motor;

track-following control means being responsive to the servo information for causing the transducer means to remain on track; and

programmable means for performing a power-saving idle operation of causing the spindle motor driver to sequentially (1) turn off all of the switching elements so that no current is provided to the spindle motor and (2) turn on selected ones of the switching elements to provide current to the spindle motor, the power-saving idle operation being performed while the track-following control means causes the transducer means to remain on track for multiple disk revolutions.