Granted Patent B1

US 9,099,147 · App. 14/492,357 · Granted Aug 4, 2015

Abstract

Claims (38)

1. A data storage device comprising:

a disk;

a spindle motor configured to rotate the disk, wherein the spindle motor comprises a plurality of windings;

a head actuated over the disk; and

control circuitry comprising an oscillator configured to drive a commutation controller configured to commutate the windings based on a commutation sequence, the control circuitry configured to:

measure a rotation phase of the spindle motor;

generate a phase error based on the measured rotation phase of the spindle motor and a phase of the commutation sequence; and

adjust a frequency of the oscillator based on the phase error.

2. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to measure the rotation phase of the spindle motor based on a back electromotive force (BEMF) voltage zero crossing of the spindle motor.

3. The data storage device as recited in claim 1 , wherein:

the disk comprises timing data; and

the control circuitry is further configured to measure the rotation phase of the spindle motor based on the timing data.

4. The data storage device as recited in claim 3 , wherein the timing data comprises servo sectors on the disk.

5. The data storage device as recited in claim 3 , wherein control circuitry is further configured to generate the phase error N times over a single revolution of the disk, where N is an integer greater than zero.

6. The data storage device as recited in claim 1 , wherein control circuitry is further configured to:

filter the phase error to generate a filtered phase error; and

adjust a frequency of the oscillator based on the filtered phase error.

7. The data storage device as recited in claim 6 , wherein control circuitry is further configured to adapt the filtering to reduce the average phase error.

8. The data storage device as recited in claim 6 , wherein control circuitry is further configured to adapt the filtering to attenuate acoustic noise.

9. The data storage device as recited in claim 6 , wherein control circuitry further comprises an acoustic sensor, and the control circuitry is further configured to adapt the filtering based on the acoustic sensor.

10. A method of operating a data storage device, the method comprising:

actuating a head over a disk;

driving a commutation sequence based on an oscillator;

measuring a rotation phase of a spindle motor configured to rotate the disk based on the commutation sequence;

generating a phase error based on the measured rotation phase of the spindle motor and a phase of the commutation sequence; and

adjusting a frequency of the oscillator based on the phase error.

11. The method as recited in claim 10 , further comprising measuring the rotation phase of the spindle motor based on a back electromotive force (BEMF) voltage zero crossing of the spindle motor.

12. The method as recited in claim 10 , wherein:

the disk comprises timing data; and

the method further comprises measuring the rotation phase of the spindle motor based on the timing data.

13. The method as recited in claim 12 , wherein the timing data comprises servo sectors on the disk.

14. The method as recited in claim 12 , further comprising generating the phase error N times over a single revolution of the disk, where N is an integer greater than zero.

15. The method as recited in claim 10 , further comprising:

filtering the phase error to generate a filtered phase error; and

adjusting a frequency of the oscillator based on the filtered phase error.

16. The method as recited in claim 15 , further comprising adapting the filtering to reduce the average phase error.

17. The method as recited in claim 15 , further comprising adapting the filtering to attenuate acoustic noise.

18. The data storage device as recited in claim 15 , further comprising adapting the filtering based on an acoustic sensor.

Assignments (8)