Data storage device having dual actuators and method for data egress throttling during emergency power off retract (EPOR)

Patent metadata

Field	Value
Publication number	US-11837264-B2
Application number	US-202217716296-A
Country	US
Kind code	B2
Filing date	Apr 8, 2022
Priority date	Apr 8, 2022
Publication date	Dec 5, 2023
Grant date	Dec 5, 2023

Abstract

A data storage device comprises a lead actuator that actuates a first read-write head over a first disk and a support actuator that actuates a second read-write head over a second disk. A spindle motor rotates the first and second disks. In response to an emergency power off (EPO) event, a processing device retracts and parks the actuators using an internal supply voltage generated from a back electromotive force (BEMF) voltage of the spindle motor, and egresses data from a volatile to a non-volatile semiconductor memory. Egress is throttled before the actuators are retracted and parked when the internal supply voltage falls to or below a first egress throttling threshold voltage. Egress is throttled after the actuators are retracted and parked when the internal supply voltage falls to or below a second egress throttling threshold voltage.

First claim

What is claimed is:

1. A data storage device comprising:
a lead actuator configured to actuate a first read-write head over a first disk;
a support actuator configured to actuate a second read-write head over a second disk;
a spindle motor configured to rotate the first disk and the second disk; and
one or more processing devices configured, in response to an emergency power off (EPO) event, to:
retract and park the lead actuator and the support actuator using an internal supply voltage generated from a back electromotive force (BEMF) voltage of the spindle motor; and
egress data from a volatile semiconductor memory to a non-volatile semiconductor memory,

wherein:
egress of data is throttled before the lead actuator and the support actuator are retracted and parked when the internal supply voltage falls to or below a first egress throttling threshold voltage, and
egress of data is throttled after the lead actuator and the support actuator are retracted and parked when the internal supply voltage falls to or below a second egress throttling threshold voltage.

2. The data storage device of claim 1 , wherein the first egress throttling threshold voltage is greater than the second egress throttling threshold voltage.

3. The data storage device of claim 2 , wherein:
the first egress throttling threshold voltage is above an actuator throttling threshold voltage at which retraction and parking of the lead actuator and support actuator is throttled; and
the second egress throttling threshold voltage is below the actuator throttling threshold voltage.

4. The data storage device of claim 3 , wherein the one or more processing devices are configured to resume egress of data when the internal supply voltage has recovered to be above the first or second egress throttling threshold voltage at which the internal supply voltage was throttled.

5. The data storage device of claim 4 , wherein the one or more processing devices are configured to allow egress of data to start at a stage selected from multiple stages of an EPO retract procedure.

6. The data storage device of claim 5 , wherein the multiple stages of the EPO retract procedure comprise a T BRAKE stage, a T PARK1 stage, a T PARK2 stage, a Hold stage and an Egress stage.

7. The data storage device of claim 5 , wherein the one or more processing devices are further configured to monitor the internal supply voltage on a 12V supply line before the lead actuator and the support actuator are retracted and parked, and to monitor the internal supply voltage on a 5V supply line after the lead actuator and the support actuator are retracted and parked.

8. The data storage device of claim 1 , wherein the one or more processing devices comprise a single power large scale integrated circuit (PLSI) for driving both the lead actuator and the support actuator to retract and park.

9. The data storage device of claim 8 , wherein the one or more processing devices further comprise a system on a chip (SoC) for egressing data, and wherein the PLSI is coupled to the SoC and controls the SoC to egress data or throttle egress of data.

10. The data storage device of claim 9 , wherein the PLSI comprises an nINT pin that is coupled to the SoC, and wherein a high signal on the nINT pin causes the SoC to egress data, and a low signal on the nINT pin causes the SoC to throttle egress of data.

11. A method for throttling data egress in a disk drive during an emergency power off (EPO) event, the method comprising:
setting a first egress throttling threshold voltage;
setting a second egress throttling threshold voltage;
when retraction and parking of an actuator configured to actuate a read-write head over a disk of the disk drive is not complete, throttling data egress when an internal supply voltage generated from a back electromotive force (BEMF) voltage of a spindle motor of the disk drive falls below the first egress throttling threshold voltage; and
when retraction and parking of the actuator is complete, throttling data egress when the internal supply voltage falls below the second egress throttling threshold voltage.

12. The method of claim 11 , wherein the first egress throttling threshold voltage is greater than the second egress throttling threshold voltage.

13. The method of claim 12 , wherein:
the first egress throttling threshold voltage is above an actuator throttling threshold voltage at which retraction and parking of the actuator is throttled; and
the second egress throttling threshold voltage is below the actuator throttling threshold voltage.

14. The method of claim 13 , further comprising:
resuming egress of data when the internal supply voltage has recovered to be above the first or second egress throttling threshold voltage at which the internal supply voltage was throttled.

15. The method of claim 14 , further comprising:
setting an egress start stage at which egress of data is started, wherein the egress start stage is selected from multiple stages of an EPO retract procedure.

16. The method of claim 15 , wherein the multiple stages of the EPO retract procedure comprise a T BRAKE stage, a T PARK1 stage, a T PARK2 stage, a Hold stage and an Egress stage.

17. The method of claim 15 , further comprising:
monitoring the internal supply voltage on a 12V supply line before the actuator is retracted and parked; and
monitoring the internal supply voltage on a 5V supply line after the actuator is retracted and parked.

18. A data storage device comprising:
a first voice control motor (VCM) configured to actuate a first read-write head over a first disk;
a second VCM configured to actuate a second read-write head over a second disk;
a spindle motor configured to rotate the first disk and the second disk;
means for retracting and parking the first VCM and the second VCM in response to an emergency power off (EPO) event; and
means for egressing data and throttling egress of data from a volatile semiconductor memory to a non-volatile semiconductor memory during the EPO event,
wherein egress of data is throttled before the first VCM and the second VCM are retracted and parked, based on a comparison of an internal supply voltage generated from a back electromotive force (BEMF) voltage of the spindle motor with a first egress throttling threshold voltage, and
wherein the first egress throttling threshold voltage is greater than an actuator throttling threshold voltage for throttling retraction and parking of the first VCM and the second VCM.

19. The data storage device of claim 18 , wherein egress of data is throttled after the first VCM and the second VCM are retracted and parked, based on comparison of the internal supply voltage with a second egress throttling threshold voltage that is less than the actuator throttling threshold voltage.

20. The data storage device of claim 19 , wherein the means for egressing data and throttling egress of data comprises a single power large scale integrated circuit (PLSI).

Assignees

• Western Digital Tech Inc

Inventors

• Johnson Brian
• Byoun Jaesoo
• Ikedo Gaku
• Ito Hideaki
• Kagami Naoyuki
• Watanabe Hiroki

Classifications

• G11B5/5569 Primary

  details of specially adapted mobile parts, e.g. electromechanical control devices (motors in general H02K) · CPC title

• G11B5/4813 Primary

  Mounting or aligning of arm assemblies, e.g. actuator arm supported by bearings, multiple arm assemblies, arm stacks or multiple heads on single arm (G11B5/484 takes precedence) · CPC title