Disk drive charging capacitor using motor supply voltage during power failure

• US 9,093,105 B2
• Filed: 12/09/2011
• Issued: 07/28/2015
• 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.
• Primary Examiner(s): ALUNKAL, THOMAS D
• Application Number:
  US13/316,128
• Publication Number:
  US 20130148240A1
• Time in Patent Office: 1,327 Days
• Field of Search: 360/73.01, 360/75, 360/272, 360/55, 360/99.08, 365/226, 365/227, 365/228, 365/10, 363/10
• 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;

a head actuated over the disk;

a microactuator configured to actuate the head;

an interface operable to receive a host supply voltage;

a capacitor, having a capacitor voltage;

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

a voltage regulator configured to receive the capacitor voltage at an input and generate a backup voltage at an output of the voltage regulator; and

control circuitry operable to;

use the boosted voltage to charge the capacitor; and

during a power failure;

stop charging the capacitor using the boosted voltage;

generate a motor supply voltage from the spindle motor;

compare the capacitor voltage to the motor supply voltage;

determine that the capacitor voltage has dropped below the motor supply voltage based on said comparison;

re-charge the capacitor using the motor supply voltage in response to said determination;

write host data associated with a pending write operation to the disk using the re-charged capacitor;

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.

2. The disk drive as recited in claim 1, wherein the control circuitry comprises a diode operable to connect the motor supply voltage to the capacitor when the capacitor voltage drops below the motor supply voltage.

3. A method of operating a disk drive comprising a disk, a spindle motor operable to rotate the disk, a head actuated over the disk, a microactuator configured to actuate the head, an interface operable to receive a host supply voltage, a capacitor having a capacitor voltage, a voltage booster configured to receive the host supply voltage and generate a boosted voltage and a voltage regulator configured to receive the capacitor voltage and generate a backup voltage, the method comprising:

using the host supply voltage to charge the capacitor; and

during a power failure;

stopping the charging of the capacitor using the host supply voltage;

generating a motor supply voltage from the spindle motor;

comparing the capacitor voltage to the motor supply voltage;

determining that the capacitor voltage has dropped below the motor supply voltage based on said comparison

re-charging the capacitor using the motor supply voltage in response to said determining;

writing host data associated with a pending write operation to the disk using the re-charged capacitor;

disconnecting the voltage booster from the host supply voltage and connecting the voltage booster to the backup voltage;

generating a boosted backup voltage using the voltage booster; and

powering the microactuator using the boosted backup voltage.

4. The method as recited in claim 3, further comprising connecting the motor supply voltage to the capacitor through a diode when the capacitor voltage drops below the motor supply voltage.

5. The method as recited in claim 3, further comprising:

charging the capacitor with the boosted voltage.