Electronic system with current conservation mechanism and method of operation thereof

• US 9,025,270 B1
• Filed: 02/24/2014
• Issued: 05/05/2015
• Est. Priority Date: 09/17/2013
• 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: Nowell, Shane G., Vinson, Wayne H., Kastler, Danny J.
• Primary Examiner(s): Sniezek, Andrew L
• Application Number:
  US14/188,381
• Time in Patent Office: 435 Days
• Field of Search: None
• US Class Current: 360/70
• CPC Class Codes: G11B 19/28 Speed controlling, regulating, or indicating G11B19/24 takes precedence
• CPC Class Codes: G11B 5/5547 "Seek" control and circuits therefor G11B5/5556 takes precedence

Abstract

An apparatus includes: a media motor; a media mounted on the media motor; a head, over the media, the motion of the head controlled by a head actuation motor; a motor driver, coupled to the media motor, configured to adjust a media speed; and control circuitry configured to: coast the media motor in preparation for accelerating the head, and activate the head actuation motor including accelerating the head in a first direction for repositioning the head over the media.

Claims

1. An apparatus comprising:

a media motor;

a media mounted on the media motor;

a head, over the media, the motion of the head being controlled by a head actuation motor;

a motor driver, coupled to the media motor, configured to adjust a media speed; and

control circuitry configured to;

coast the media motor in preparation for accelerating the head,

activate the head actuation motor including accelerating the head in a first direction for repositioning the head over the media,

increase a speed of the media motor by a fixed percentage in a motor pitch region after accelerating the head, and

coast the media motor in preparation for decelerating the head.

2. The apparatus as claimed in claim 1 wherein the motor driver configured to reduce a motor driver current for coasting the media motor.

3. The apparatus as claimed in claim 1 wherein the head actuation motor receives an acceleration current for accelerating the head in the first direction.

4. The apparatus as claimed in claim 1 wherein the control circuitry is further configured to cause the motor driver to monitor the media speed of the media motor with the motor current reduced.

5. The apparatus as claimed in claim 1 wherein the control circuitry is further configured to cause the motor driver to activate a commutation of the media motor when the head has a constant velocity.

6. The apparatus as claimed in claim 1 wherein the control circuitry is further configured to cause the motor driver to increase the media speed prior to the decelerating of the head in the first direction.

7. The apparatus as claimed in claim 1 wherein the control circuitry is further configured to cause the head to accelerate in a direction opposite the first direction.

8. The apparatus as claimed in claim 1 wherein the control circuitry is further configured to coast the media motor in preparation for accelerating the head in a direction opposite the first direction.

9. The apparatus as claimed in claim 1 wherein the control circuitry is further configured to coordinate the media motor and the head actuation motor for reducing a peak current.

10. The apparatus as claimed in claim 1 wherein the control circuitry is further configured to detect a deceleration window of the head actuation motor and activate the motor driver for recovering a media speed within a seek settle window.

11. A method of operating an apparatus, the method comprising:

controlling a media motor having a media attached;

positioning a head over a media;

adjusting a media speed for the media;

disengaging a motor driver for coasting the media;

activating a head actuation motor, with the media coasting, for accelerating the head in a first direction including repositioning the head over the media;

reengaging the motor driver for increasing the media speed of the media by a fixed percentage in a motor pitch region after accelerating the head; and

coasting the media motor again in preparation for decelerating the head.

12. The method as claimed in claim 11 wherein adjusting the media speed includes maintaining a constant speed.

13. The method as claimed in claim 11 wherein increasing the media speed includes ramping to a pitch speed.

14. The method as claimed in claim 11 wherein activating the head actuation motor with the media coasting includes dropping a motor driver current of the motor driver to zero while increasing an acceleration current of the head actuation motor.

15. The method as claimed in claim 11 further comprising activating the motor driver for commutating the media motor when the head has a constant velocity.

16. The method as claimed in claim 11 wherein activating the head actuation motor includes increasing an acceleration current, for accelerating the head in the first direction, with a motor drive current reduced.

17. The method as claimed in claim 11 wherein activating the head actuation motor includes increasing an acceleration current, for accelerating the head in a direction opposite the first direction, with a motor drive current removed.

18. The method as claimed in claim 11 wherein disengaging the motor driver for coasting the media includes decreasing the media speed to within a range that corresponds to the head'"'"'s capability to read servo data.

19. The method as claimed in claim 11 wherein disengaging the motor driver for coasting the media includes coordinating the media motor and the head actuation motor for reducing a peak current.

20. The method as claimed in claim 11 further comprising detecting a deceleration window of the head actuation motor including recovering the media speed within a seek settle window.

21. A method of operating an apparatus, the method comprising:

controlling a media coupled to a media motor;

positioning a head over the media;

adjusting a media speed for the media;

disengaging a motor driver for coasting the media;

harvesting a free-wheel current from inertia of the media motor;

activating a head actuation motor, using the free-wheel current, for accelerating the head in a direction including repositioning the head over the media;

reengaging the motor driver for increasing the media speed of the media motor by a fixed percentage in a motor pitch region after acceleration the head; and

coasting the media motor again in preparation for decelerating head.

22. The method as claimed in claim 21 wherein adjusting the media speed includes increasing the media speed in the motor pitch region, decelerating the media motor during the harvesting of the free-wheel current, and returning the media speed to a nominal value after decelerating the head.