Data storage device optimizing spindle motor power when transitioning into a power failure mode

Patent metadata

Field	Value
Publication number	US-9230593-B1
Application number	US-201414582068-A
Country	US
Kind code	B1
Filing date	Dec 23, 2014
Priority date	Dec 23, 2014
Publication date	Jan 5, 2016
Grant date	Jan 5, 2016

Abstract

A data storage device is disclosed comprising a spindle motor configured to rotate a disk, wherein the spindle motor comprises a plurality of windings. The windings are commutated based on a commutation sequence while applying a driving voltage to each winding, wherein the driving voltage comprises an operating amplitude during normal operation. When a supply voltage falls below a threshold, the spindle motor is configured into a power generator by at least reducing the amplitude of the driving voltage to substantially zero and then incrementally increasing the amplitude of the driving voltage by at least two steps toward the operating amplitude.

First claim

What is claimed is:

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 powered by a supply voltage, the control circuitry configured to:
commutate the windings based on a commutation sequence while applying a driving voltage to each winding, wherein the driving voltage comprises an operating amplitude during normal operation; and
when the supply voltage falls below a threshold, configure the spindle motor into a power generator by at least reducing the amplitude of the driving voltage to substantially zero and then incrementally increasing the amplitude of the driving voltage by at least two steps toward the operating amplitude.

2. The data storage device as recited in claim 1 , wherein increasing the amplitude of the driving voltage by at least two steps comprises increasing the amplitude until the amplitude substantially equals a back electromotive force (BEMF) voltage across each winding.

3. The data storage device as recited in claim 1 , wherein increasing the amplitude of the driving voltage by at least two steps comprises increasing the amplitude until the amplitude exceeds a back electromotive force (BEMF) voltage across each winding.

4. The data storage device as recited in claim 1 , wherein:
the driving voltage applied to each winding comprises a sinusoidal voltage; and
the driving voltage applied to each winding comprises a phase corresponding to phase of a back electromotive force (BEMF) voltage across each winding.

5. The data storage device as recited in claim 4 , wherein the driving voltage applied to each winding comprises a pulse width modulated (PWM) voltage.

6. The data storage device as recited in claim 1 , wherein the disk comprises a plurality of servo tracks defined by servo sectors, and the control circuitry is further configured to increase the amplitude of the driving voltage when the head reaches a first servo sector by a first step increment and then step increase the amplitude of the driving voltage when the head reaches a second servo sector following the first servo sector by a second step increment.

7. The data storage device as recited in claim 6 , wherein the first step increment and the second step increment are selected to increase a power generated by the spindle motor when the head is near the first servo sector.

8. A method of operating a data storage device, the method comprising:
commutating windings of a spindle motor configured to rotate a disk based on a commutation sequence while applying a driving voltage to each winding, wherein the driving voltage comprises an operating amplitude during normal operation; and
when a supply voltage falls below a threshold, configuring the spindle motor into a power generator by at least reducing the amplitude of the driving voltage to substantially zero and then incrementally increasing the amplitude of the driving voltage by at least two steps toward the operating amplitude.

9. The method as recited in claim 8 , wherein increasing the amplitude of the driving voltage by at least two steps comprises increasing the amplitude until the amplitude substantially equals a back electromotive force (BEMF) voltage across each winding.

10. The method as recited in claim 8 , wherein increasing the amplitude of the driving voltage by at least two steps comprises increasing the amplitude until the amplitude exceeds a back electromotive force (BEMF) voltage across each winding.

11. The method as recited in claim 8 , wherein:
the driving voltage applied to each winding comprises a sinusoidal voltage; and
the driving voltage applied to each winding comprises a phase corresponding to phase of a back electromotive force (BEMF) voltage across each winding.

12. The method as recited in claim 11 , wherein the driving voltage applied to each winding comprises a pulse width modulated (PWM) voltage.

13. The method as recited in claim 8 , wherein the disk comprises a plurality of servo tracks defined by servo sectors, and the method further comprises increasing the amplitude of the driving voltage when a head reaches a first servo sector by a first step increment and then step increasing the amplitude of the driving voltage when the head reaches a second servo sector following the first servo sector by a second step increment.

14. The method as recited in claim 13 , wherein the first step increment and the second step increment are selected to increase a power generated by the spindle motor when the head is near the first servo sector.

Assignees

• Western Digital Tech Inc

Inventors

• Nicholls Michael T

Classifications

• G11B19/2081

  emergency power-down · CPC title

• G11B21/12 Primary

  Raising and lowering; Back-spacing or forward-spacing along track; Returning to starting position {otherwise than during transducing operation} · CPC title

• G11B19/20 Primary

  Driving; Starting; Stopping; Control thereof · CPC title

• G11B19/28 Primary

  Speed controlling, regulating, or indicating (G11B19/24 takes precedence) · CPC title