Data storage device adjusting spindle motor current based on continuous function of voice coil current during seek
A data storage device is disclosed comprising a spindle motor configured to rotate a disk, and a first voice coil motor (VCM) configured to actuate a head over the disk. During at least fifty percent of a seek of the head over the disk, a spindle control signal is generated based on a continuous function of a current flowing through the first VCM, and the spindle control signal is applied to the spindle motor.
1. A data storage device comprising:
a disk;
a spindle motor configured to rotate the disk;
a first head;
a first voice coil motor (VCM) configured to actuate the first head over the disk; and
control circuitry configured to:
first seek the first head over the disk;
during at least fifty percent of the first seek, generate a spindle control signal based on a continuous function of a current flowing through the first VCM; and
apply the spindle control signal to the spindle motor during the at least fifty percent of the first seek.
2. The data storage device as recited in claim 1 , wherein the continuous function maintains a combined current of a current flowing through the spindle motor and the current flowing through the first VCM substantially constant during the at least fifty percent of the first seek.
3. The data storage device as recited in claim 1 , wherein the continuous function comprises a linear function.
4. The data storage device as recited in claim 3 , wherein when the spindle control signal applied to the spindle motor causes current to flow into the spindle motor, the linear function comprises:
Max_Spin− K 1 *Ivcm
where max_spin represents a maximum for the spindle control signal, Ivcm represents the current flowing through the first VCM, and K1 represents a predetermined gain.
5. The data storage device as recited in claim 4 , wherein when the spindle control signal applied to the spindle motor causes the spindle motor to source current to the first VCM, the linear function comprises:
COD− K 2*( Ivcm −(Max_Spin−COD)/ K 1)
where COD (change of direction) represents a threshold for the spindle control signal wherein the spindle motor begins sourcing current to the first VCM and K2 represents a predetermined gain.
6. The data storage device as recited in claim 5 , wherein K1 is greater than K2.
7. The data storage device as recited in claim 1 , wherein:
during an acceleration phase of the first seek, the continuous function comprises a first function; and
during a deceleration phase of the first seek, the continuous function comprises a second function different from the first function.
8. The data storage device as recited in claim 1 , further comprising:
a second head; and
a second VCM configured to actuate the second head over the disk,
wherein during the at least fifty percent of the first seek the control circuitry is further configured to:
second seek the second head over the disk; and
generate the spindle control signal based on a continuous function of a combined current flowing through the first VCM and the second VCM.
9. A method of operating a data storage device, the method comprising:
rotating a disk using a spindle motor;
actuating a first head over the disk using a first voice coil motor (VCM);
first seeking the first head over the disk; and
during at least fifty percent of the first seek, generating a spindle control signal based on a function of a current flowing through the first VCM; and
applying the spindle control signal to the spindle motor during the at least fifty percent of the first seek,
wherein the function maintains a combined current of a current flowing through the spindle motor and the current flowing through the first VCM substantially constant.
10. The method as recited in claim 9 , wherein the function is a continuous function.
11. The method as recited in claim 10 , wherein the continuous function comprises a linear function.
12. The method as recited in claim 11 , wherein when the spindle control signal applied to the spindle motor causes current to flow into the spindle motor, the linear function comprises:
Max_Spin− K 1 *Ivcm
where max_spin represents a maximum for the spindle control signal, Ivcm represents the current flowing through the first VCM, and K1 represents a predetermined gain.
13. The method as recited in claim 12 , wherein when the spindle control signal applied to the spindle motor causes the spindle motor to source current to the first VCM, the linear function comprises:
COD− K 2*( Ivcm −(Max_Spin−COD)/ K 1)
where COD (change of direction) represents a threshold for the spindle control signal wherein the spindle motor begins sourcing current to the first VCM and K2 represents a predetermined gain.
14. The method as recited in claim 13 , wherein K1 is greater than K2.
15. The method as recited in claim 9 , wherein:
during an acceleration phase of the first seek, the function comprises a first function; and
during a deceleration phase of the first seek, the function comprises a second function different from the first function.
16. The method as recited in claim 9 , wherein during the at least fifty percent of the first seek the method further comprises:
actuating a second head over the disk using a second VCM;
second seeking the second head over the disk; and
generating the spindle control signal based on a function of a combined current flowing through the first VCM and the second VCM.
17. Control circuitry configured to:
during at least fifty percent of a first seek, generate a spindle control signal based on a continuous function of a current flowing through a first voice coil motor (VCM) configured to actuate a first head over a disk; and
apply the spindle control signal to a spindle motor during the at least fifty percent of the first seek, wherein the spindle motor is configured to rotate the disk.
18. The control circuitry as recited in claim 17 , wherein the continuous function maintains a combined current of a current flowing through the spindle motor and the current flowing through the first VCM substantially constant during the at least fifty percent of the first seek.
19. The control circuitry as recited in claim 17 , wherein the continuous function comprises a linear function.
20. The control circuitry as recited in claim 19 , wherein when the spindle control signal applied to the spindle motor causes current to flow into the spindle motor, the linear function comprises:
Max_Spin− K 1 *Ivcm
where max_spin represents a maximum for the spindle control signal, Ivcm represents the current flowing through the first VCM, and K1 represents a predetermined gain.
21. The control circuitry as recited in claim 20 , wherein when the spindle control signal applied to the spindle motor causes the spindle motor to source current to the first VCM, the linear function comprises:
COD− K 2*( Ivcm −(Max_Spin−COD)/ K 1)
where COD (change of direction) represents a threshold for the spindle control signal wherein the spindle motor begins sourcing current to the first VCM and K2 represents a predetermined gain.
22. The control circuitry as recited in claim 21 , wherein K1 is greater than K2.
23. The control circuitry as recited in claim 17 , wherein:
during an acceleration phase of the first seek, the continuous function comprises a first function; and
during a deceleration phase of the first seek, the continuous function comprises a second function different from the first function.
24. The control circuitry as recited in claim 17 , wherein during the at least fifty percent of the first seek the control circuitry is further configured to generate the spindle control signal based on a continuous function of a combined current flowing through the first VCM and a second VCM while concurrently seeking the first VCM and the second VCM.