POWER FAILURE MANAGEMENT IN DISK DRIVES

• US 20150310886A1
• Filed: 07/07/2015
• Published: 10/29/2015
• Est. Priority Date: 12/09/2011
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: FERRIS, TIMOTHY A., RYAN, ROBERT P.
• Granted Patent: US 9,390,749 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G11B 19/047 Recovery from power failure
• CPC Class Codes: G11B 19/20 Driving; Starting; Stopping; Control thereof
• CPC Class Codes: G11B 5/54 with provision for moving the head into or out of its operative position or across tracks
• CPC Class Codes: H02P 25/028 with four quadrant control
• CPC Class Codes: H02P 25/034 Voice coil motors voice coil motors driven by DC power H02P7/025
• CPC Class Codes: H02P 3/14 by regenerative braking

Abstract

A disk drive is disclosed comprising a disk, a spindle motor operable to rotate the disk, a head actuated over the disk, an interface operable to receive a host supply voltage, and a capacitor. The host supply voltage is used to charge the capacitor to a capacitor voltage higher than the host supply voltage. During a power failure, the host supply voltage stops charging the capacitor, and a motor supply voltage is generated from the spindle motor. The capacitor voltage is used to operate control circuitry, and when the capacitor voltage decays below the motor supply voltage, the motor supply voltage charges the capacitor.

Claims

1. A disk drive comprising:

a disk;

a spindle motor operable to rotate the disk;

an interface configured to receive a host supply voltage;

a power storage device; and

control circuitry configured to;

use the host supply voltage to charge the power storage device; and

during a power failure;

stop charging the power storage device using the host supply voltage;

generate a motor supply voltage from the spindle motor;

use power from the power storage device to write a first portion of host data associated with a pending write operation to the disk;

compare a voltage level of the power storage device to the motor supply voltage to determine when the voltage level of the power storage device becomes less than the motor supply voltage;

re-charge the power storage device using the motor supply voltage when it is determined that the voltage level of the power storage device has become less than the motor supply voltage; and

write a second portion of the host data to the disk using the re-charged power storage device.

2. The disk drive of claim 1, wherein the control circuitry is further configured to use the host supply voltage to charge the power storage device to a voltage level higher than the host supply voltage.

3. The disk drive of claim 1, further comprising voltage boosting circuitry configured to receive the host supply voltage and generate a boosted voltage.

4. The disk drive of claim 3, wherein the control circuitry is further configured to use the boosted voltage to charge the power storage device.

5. The disk drive of claim 1, wherein the control circuitry is further configured to stop charging the power storage device using the host supply voltage at least in part by operating a first switch to disconnect the host supply voltage from the power storage device.

6. The disk drive of claim 5, wherein the control circuitry is further configured to stop charging the power storage device using the host supply voltage at least in part by operating a second switch to disconnect the control circuitry from the host supply voltage and connect the control circuitry to the power storage device.

7. The disk drive of claim 1, further comprising a diode connected between the motor supply voltage and the power storage device, the diode being configured to compare the motor supply voltage to the voltage level of the power storage device and allow the motor supply voltage to power the power storage device when the motor supply voltage is greater than the voltage level of the power storage device.

8. The disk drive of claim 7, wherein the diode is forward biased from the motor supply voltage to the power storage device.

9. The disk drive of claim 1, further comprising a voltage regulator configured to receive backup power from the power storage device and provide the backup power to the control circuitry.

10. The disk drive of claim 1, wherein the control circuitry is further configured to use the motor supply voltage to power a voice coil motor (VCM) when the voltage level of the power storage device is greater than the motor supply voltage.

11. A disk drive comprising:

a disk;

a head configured to write data to the disk;

a microactuator configured to actuate the head;

an interface operable to receive a host supply voltage;

a power storage device configured to store a backup voltage;

a voltage booster configured to receive the host supply voltage at an input and generate a boosted host supply voltage; and

control circuitry configured to, in response to a power failure event;

disconnect the voltage booster input from the host supply voltage and connect the voltage booster input to the backup voltage;

generate a boosted backup voltage using the voltage booster; and

power the microactuator using the boosted backup voltage.

12. The disk drive of claim 11, wherein the control circuitry is further configured to power the microactuator using the boosted host supply voltage during normal operation.

13. The disk drive of claim 11, wherein the microactuator is a piezoelectric microactuator.

14. The disk drive of claim 11, wherein the control circuitry is further configured to charge the power storage device using the boosted host supply voltage during normal operation.

15. The disk drive of claim 14, wherein the control circuitry is further configured to charge the power storage device to a voltage level greater than the host supply voltage.

16. The disk drive of claim 11, further comprising a first switch configured to selectively connect the voltage booster input to the host supply voltage or the backup voltage, wherein the control circuitry is further configured to disconnect the voltage booster input from the host supply voltage and connect the voltage booster input to the backup voltage at least in part by operating the first switch.

17. The disk drive of claim 16, further comprising a second switch configured to selectively connect the control circuitry to the host supply voltage or the backup voltage, wherein the control circuitry is further configured to, in response to the power failure event, disconnect the control circuitry from the host supply voltage and connect the control circuitry to the backup voltage by operating the second switch.

18. The disk drive of claim 11, further comprising a diode connected between a motor supply voltage and the power storage device.

19. The disk drive of claim 18, wherein the diode is configured to allow the motor supply voltage to charge the power storage device when the motor supply voltage is greater than a voltage level of the power storage device.

20. A device comprising:

control circuitry configured to;

use a host supply voltage received via an interface to charge a power storage device; and

during a power failure;

stop charging the power storage device using the host supply voltage;

generate a motor supply voltage from a spindle motor operable to rotate a disk;

use power from the power storage device to write a first portion of host data associated with a pending write operation to the disk;

compare a voltage level of the power storage device to the motor supply voltage to determine when the voltage level of the power storage device becomes less than the motor supply voltage;

re-charge the power storage device using the motor supply voltage when it is determined that the voltage level of the power storage device has become less than the motor supply voltage; and

write a second portion of the host data to the disk using the re-charged power storage device.

21. The device of claim 20, wherein the control circuitry is further configured to use the host supply voltage to charge the power storage device to a voltage level higher than the host supply voltage.

22. The device of claim 20, further comprising voltage boosting circuitry configured to receive the host supply voltage and generate a boosted voltage.

23. The device of claim 22, wherein the control circuitry is further configured to use the boosted voltage to charge the power storage device.

24. The device of claim 20, wherein the control circuitry is further configured to stop charging the power storage device using the host supply voltage at least in part by operating a first switch to disconnect the host supply voltage from the power storage device.

25. The device of claim 24, wherein the control circuitry is further configured to stop charging the power storage device using the host supply voltage at least in part by operating a second switch to disconnect the control circuitry from the host supply voltage and connect the control circuitry to the power storage device.

26. The device of claim 20, further comprising a diode connected between the motor supply voltage and the power storage device, the diode being configured to compare the motor supply voltage to the voltage level of the power storage device and allow the motor supply voltage to power the power storage device when the motor supply voltage is greater than the voltage level of the power storage device.

27. The device of claim 26, wherein the diode is forward biased from the motor supply voltage to the power storage device.

28. The device of claim 20, further comprising a voltage regulator configured to receive backup power from the power storage device and provide the backup power to the control circuitry.

29. The device of claim 20, wherein the control circuitry is further configured to use the motor supply voltage to power a voice coil motor (VCM) when the voltage level of the power storage device is greater than the motor supply voltage.