Servo writer with retract capacitor for generating a VCM driving current during a power failure

1. A servo writer for writing servo data onto a disk of a disk drive, the servo writer comprising:

a push-pin operable to contact an actuator arm of the disk drive, wherein the actuator arm comprises a voice coil coupled to a base of the actuator arm and a head coupled to a distal end of the actuator arm;

an actuator for actuating the push-pin;

a retract capacitor; and

control circuitry operable to apply a current from the retract capacitor to the voice coil in order to retract the actuator arm if a power failure occurs while actuating the push-pin;

wherein:

the control circuitry comprises a voltage regulator for generating a regulated voltage in response to the retract capacitor, where the regulated voltage is applied across the voice coil to generate the current applied to the voice coil;

the voltage regulator is configurable to apply a maximum current to the voice coil selected from a plurality of possible maximum currents; and

the maximum current is selected based on a type of disk drive being servo written.

2. The servo writer as recited in claim 1 , wherein the voltage regulator comprises a resistor in series with the voice coil.

3. The servo writer as recited in claim 2 , wherein the resistor is adjustable.

4. The servo writer as recited in claim 1 , further comprising a manually configured switch for configuring the voltage regulator.

5. The servo writer as recited in claim 1 , further comprising a plurality of switches for configuring a direction of the current applied to the voice coil, thereby configuring a retract direction of the actuator arm.

6. The servo writer as recited in claim 5 , wherein the direction of the current is configured based on a type of disk drive being servo written.

7. The servo writer as recited in claim 5 , wherein the switches are configured manually.

8. A method for writing servo data onto a disk of a disk drive, wherein the disk drive comprises an actuator arm including a voice coil coupled to a base of the actuator arm and a head coupled to a distal end of the actuator arm, the method comprising:

actuating a push-pin to move the actuator arm;

applying a current from a retract capacitor to the voice coil in order to retract the actuator arm if a power failure occurs while actuating the push-pin; and

generating a regulated voltage in response to the retract capacitor, where the regulated voltage is applied across the voice coil to generate the current applied to the voice coil;

wherein:

the regulated voltage is generated to apply a maximum current to the voice coil selected from a plurality of possible maximum currents; and

the maximum current is selected based on a type of disk drive being servo written.

9. The method as recited in claim 8 , further comprising adjusting a resistor to generate the regulated voltage.

10. The method as recited in claim 8 , further comprising manually configuring a switch to generate the regulated voltage.

11. The method as recited in claim 8 , further comprising selecting a direction of the current applied to the voice coil, thereby configuring a retract direction of the actuator arm.

12. The method as recited in claim 11 , wherein the direction of the current is selected based on a type of disk drive being servo written.

13. The method as recited in claim 11 , further comprising configuring switches to select the direction of the current applied to the voice coil.

14. The method as recited in claim 13 , wherein the switches are manually configured.

15. A servo writer for writing servo data onto a disk of a disk drive, the servo writer comprising:

a push-pin operable to contact an actuator arm of the disk drive, wherein the actuator arm comprises a voice coil coupled to a base of the actuator arm and a head coupled to a distal end of the actuator arm;

an actuator for actuating the push-pin;

a retract capacitor;

control circuitry operable to apply a current from the retract capacitor to the voice coil in order to retract the actuator arm if a power failure occurs while actuating the push-pin; and

a plurality of switches for configuring a direction of the current applied to the voice coil, thereby configuring a retract direction of the actuator arm.

16. The servo writer as recited in claim 15 , wherein the direction of the current is configured based on a type of disk drive being servo written.

17. The servo writer as recited in claim 15 , wherein the switches are configured manually.

18. A method for writing servo data onto a disk of a disk drive, wherein the disk drive comprises an actuator arm including a voice coil coupled to a base of the actuator arm and a head coupled to a distal end of the actuator arm, the method comprising:

actuating a push-pin to move the actuator arm;

applying a current from a retract capacitor to the voice coil in order to retract the actuator arm if a power failure occurs while actuating the push-pin; and

selecting a direction of the current applied to the voice coil, thereby configuring a retract direction of the actuator arm.

19. The method as recited in claim 18 , wherein the direction of the current is selected based on a type of disk drive being servo written.

20. The method as recited in claim 18 , further comprising configuring switches to select the direction of the current applied to the voice coil.