Data storage device employing balanced current drive to unload multiple voice coil motors

Patent metadata

Field	Value
Publication number	US-9997182-B1
Application number	US-201715808719-A
Country	US
Kind code	B1
Filing date	Nov 9, 2017
Priority date	Nov 9, 2017
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

A data storage device is disclosed comprising a first voice coil motor (VCM) comprising a first voice coil configured to actuate a first head over a first disk, a second VCM comprising a second voice coil configured to actuate a second head over a second disk, and a spindle motor configured to rotate the first and second disk, wherein during a power failure the first and second disks rotating causes the spindle motor to generate a back electromotive force (BEMF) voltage. During the power failure the first and second VCMs are unloaded, wherein during a first interval the first voice coil is connected to the BEMF voltage and the second voice coil is disconnected from the BEMF voltage, and during a second interval the second voice coil is connected to the BEMF voltage and the first voice coil is disconnected from the BEMF voltage.

First claim

What is claimed is:

1. A data storage device comprising:
a first voice coil motor (VCM) comprising a first voice coil configured to actuate a first head over a first disk;
a second VCM comprising a second voice coil configured to actuate a second head over a second disk;
a spindle motor configured to rotate the first and second disk, wherein during a power failure the first and second disks rotating causes the spindle motor to generate a back electromotive force (BEMF) voltage; and
control circuitry configured to unload the first VCM and the second VCM during the power failure by at least:
(a) during a first interval, connecting the first voice coil to the BEMF voltage and disconnecting the second voice coil from the BEMF voltage;
(b) during a second interval different from the first interval, connecting the second voice coil to the BEMF voltage and disconnecting the first voice coil from the BEMF voltage; and
(c) repeating elements (a) and (b) at least once.

2. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to unload the first VCM and the second VCM during the power failure by:
during the first interval, shorting the second voice coil; and
during the second interval, shorting the first voice coil.

3. The data storage device as recited in claim 1 , wherein during a third interval different from the first and second intervals, the control circuitry is further configured to unload the first VCM and the second VCM during the power failure by:
connecting the first voice coil to the BEMF voltage; and
connecting the second voice coil to the BEMF voltage.

4. The data storage device as recited in claim 1 , wherein during a third interval different from the first and second intervals, the control circuitry is further configured to unload the first VCM and the second VCM during the power failure by:
disconnecting the first voice coil from the BEMF voltage; and
disconnecting the second voice coil from the BEMF voltage.

5. The data storage device as recited in claim 4 , wherein during at least part of the third interval, the control circuitry is further configured to unload the first VCM and the second VCM during the power failure by:
shorting the first voice coil; and
shorting the second voice coil.

6. A method of operating a data storage device, the method comprising unloading a first (voice coil motor) VCM and a second VCM during a power failure, the unloading comprising:
(a) during a first interval, connecting a first voice coil of the first VCM to a back electromotive force (BEMF) voltage generated by a spindle motor, and disconnecting a second voice coil of the second VCM from the BEMF voltage;
(b) during a second interval different from the first interval, connecting a second voice coil of the second VCM to the BEMF voltage and disconnecting the first voice coil from the BEMF voltage; and
(c) repeating elements (a) and (b) at least once.

7. The method as recited in claim 6 , wherein the unloading the first VCM and the second VCM during the power failure further comprises:
during the first interval, shorting the second voice coil; and
during the second interval, shorting the first voice coil.

8. The method as recited in claim 6 , wherein during a third interval different from the first and second intervals, the unloading the first VCM and the second VCM during the power failure further comprises:
connecting the first voice coil to the BEMF voltage; and
connecting the second voice coil to the BEMF voltage.

9. The method as recited in claim 6 , wherein during a third interval different from the first and second intervals, the unloading the first VCM and the second VCM during the power failure further comprises:
disconnecting the first voice coil from the BEMF voltage; and
disconnecting the second voice coil from the BEMF voltage.

10. The method as recited in claim 9 , wherein during at least part of the third interval, the unloading the first VCM and the second VCM during the power failure further comprises:
shorting the first voice coil; and
shorting the second voice coil.

Assignees

• Western Digital Tech Inc

Inventors

• Tanner Brian K
• Ng James J

Classifications

• G11B5/54 Primary

  with provision for moving the head into or out of its operative position or across tracks · CPC title

• G11B5/5547

  "Seek" control and circuits therefor (G11B5/5556 takes precedence) · 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

• G11B21/083

  on discs · CPC title

• G11B5/553

  Details · CPC title