DISK DRIVE CHARGING CAPACITOR USING MOTOR SUPPLY VOLTAGE DURING POWER FAILURE

• US 20130148240A1
• Filed: 12/09/2011
• Published: 06/13/2013
• Est. Priority Date: 12/09/2011
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: RYAN, ROBERT P., FERRIS, TIMOTHY A.
• Granted Patent: US 9,093,105 B2
• Time in Patent Office: Days
• US Class Current: 360/99.08
• 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 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;

an interface operable to receive a host supply voltage;

a capacitor; and

control circuitry operable to;

use the host supply voltage to charge the capacitor to a capacitor voltage higher than the host supply voltage; and

during a power failure;

stop charging the capacitor using the host supply voltage;

generate a motor supply voltage from the spindle motor;

use the capacitor voltage to operate the control circuitry; and

when the capacitor voltage decays below the motor supply voltage, charge the capacitor using the motor supply 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 decays below the motor supply voltage.

3. The disk drive as recited in claim 1, wherein the control circuitry is operable to:

boost the host supply voltage to a boosted voltage higher than the host supply voltage; and

charge the capacitor with the boosted voltage.

4. The disk drive as recited in claim 3, further comprising a microactuator operable to actuate the head radially over the disk, wherein the control circuitry is operable to control the microactuator using the boosted voltage.

5. A method of operating a disk drive 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 method comprising:

using the host supply voltage to charge the capacitor to a capacitor voltage higher than the host supply voltage; 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;

using the capacitor voltage to operate control circuitry; and

when the capacitor voltage decays below the motor supply voltage, charging the capacitor using the motor supply voltage.

6. The method as recited in claim 5, further comprising connecting the motor supply voltage to the capacitor through a diode when the capacitor voltage decays below the motor supply voltage.

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

boosting the host supply voltage to a boosted voltage higher than the host supply voltage; and

charging the capacitor with the boosted voltage.

8. The method as recited in claim 7, wherein the disk drive further comprises a microactuator operable to actuate the head radially over the disk, the method further comprising controlling the microactuator using the boosted voltage.