Acoustical noise reduction for a data storage device

• US 7,190,542 B2
• Filed: 02/20/2004
• Issued: 03/13/2007
• Est. Priority Date: 08/13/2003
• Status: Expired due to Fees

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Ooi, KianKeong, Yeo, KianSoon, Shu, JiaHong, Teng, JackMing
• Primary Examiner(s): Korzuch; William
• Assistant Examiner(s): NEGRON, DANIELL L
• Application Number:
  US10/783,818
• Publication Number:
  US 20050046992A1
• Time in Patent Office: 1,117 Days
• Field of Search: None
• US Class Current: 360/69
• CPC Class Codes: G11B 21/22 while the head is out of operative position
• CPC Class Codes: G11B 33/1406 Reducing the influence of the temperature
• CPC Class Codes: G11B 5/54 with provision for moving the head into or out of its operative position or across tracks

Abstract

A method, apparatus, and combination for reducing acoustical noise at start-up of a device is disclosed. The method includes the steps of determining an internal temperature of the device, and unlatching an actuator of the device based on the determined internal temperature of the device, by steps for unlatching the actuator of the device. The apparatus includes a thermistor providing a resistance value to a controller that selects an unlatch process based on the resistance value of the thermistor, and an unlatch procedure programmed into the controller executing the selected unlatch process. The device combination includes a base deck supporting an actuator confined by a magnetic latch for periods of inactivity, and unlatched from the magnetic latch for periods of activity by steps for unlatching the actuator.

Claims

1. A method comprising steps of:

(a) determining an internal temperature of a device having an actuator and a latch configured to latch the actuator;

(b) comparing the internal temperature to a predetermined threshold value;

(c) initiating a DC current unlatch process for unlatching the actuator if the internal temperature is greater than the predetermined temperature threshold value; and

in the alternative

(d) initiating an AC current unlatch process for unlatching the actuator if the internal temperature is less than the predetermined temperature threshold value.

2. The method of claim 1, which the device is a head-disc assembly, and in which determining step (a) comprises:

reading a thermistor to determine a value of the thermistor, wherein the value of the thermistor corresponds to the internal temperature of the head-disc assembly.

3. The method of claim 1, in which the latch is a magnetic latch, and in which the DC current unlatch process of step (c) further comprises steps of;

(c)(1) selecting an initial DC current;

(c)(2) applying the initial DC current across a coil of the actuator for an initial time interval;

(c)(3) measuring a response of the coil to the initially applied DC current;

(c)(4) determining whether the actuator has been successfully unlatched from the magnetic latch based on the response of the coil to the applied DC current;

(c)(5) increasing incrementally the initial DC current to a predetermined maximum DC current level;

(c)(6) measuring the response of the coil to each incremental increase in the initial DC current up to the predetermined maximum DC current level to determine whether the actuator has been successfully unlatched from the magnetic latch;

(c)(7) expanding incrementally the initial time interval to a predetermined maximum time interval when the predetermined maximum DC current level applied across the coil for the initial time interval has been unsuccessful in unlatching of the actuator from the magnetic latch;

(c)(8) evaluating the response of the coil to each incremental increase in the initial time interval up to the predetermined maximum time interval to determine whether the actuator has been successfully unlatched from the magnetic latch.

4. The method of claim 3, in which the AC current unlatch process of step (d) further comprises the steps of:

(d)(1) selecting an initial AC current;

(d)(2) applying the initial AC current across a coil of the actuator for a predetermined time interval;

(d)(3) measuring a response of the coil to the initially applied AC current;

(d)(4) determining whether the actuator has been successfully unlatched from the magnetic latch based on the response of the coil to the applied current;

(d)(5) increasing incrementally the initial AC current to a predetermined maximum AC current level;

(d)(6) measuring the response of the coil to each incremental increase in the initial AC current up to the predetermined maximum AC current level to determine whether the actuator has been successfully unlatched from the magnetic latch; and

(d)(7) reporting an unlatch failure upon an unsuccessfully unlatching of the actuator from the magnetic latch.

5. The method of claim 3, further comprising a step of:

(c)(9) switching to the AC current unlatch process when the predetermined maximum DC current level applied across the coil for the predetermined maximum, time interval has been unsuccessful in unlatching the actuator from the magnetic latch.

6. The method of claim 1, in which the latch is a magnetic latch, and in which the AC unlatch process of step (d) further comprises the steps of:

(d)(1) selecting an initial AC current;

(d)(2) applying the initial AC current across a coil of the actuator for a predetermined time interval;

(d)(3) measuring a response of the coil to the initially applied AC current;

(d)(4) determining whether the actuator has been successfully unlatched from the magnetic latch based on the response of the coil to the applied current;

(d)(5) increasing incrementally the initial AC current to a predetermined maximum AC current level;

(d)(6) measuring the response of the coil to each incremental increase in the initial AC current up to the predetermined maximum AC current level to determine whether the actuator has been successfully unlatched from the magnetic latch; and

(d)(7) reporting an unlatch failure upon an unsuccessfully unlatching of the actuator from the magnetic latch.

7. The method of claim 1, in which the DC current unlatch process of step (c) further comprises steps of

(c)(1) determining whether the DC current unlatch process has successfully unlatched the actuator;

and

(c)(2) initiating the AC current unlatch process of step (d) if the actuator has not been successfully unlatched.

8. A device comprising:

an actuator confined by a latch during period of inactivity;

a thermistor providing a value;

a controller responsive to the value of the thermistor selecting an unlatch process that unlatches an actuator of the device; and

an unlatch procedure programmed into the controller executing a DC current unlatch process if the thermistor value falls within a first range of predetermined values and art AC current unlatch process if the thermistor value falls within a second range of predetermined values.

9. The device of claim 8 in which the latch further comprises a magnetic latch configured to latch the actuator.

10. The device of claim 9, in which the unlatch procedure executes the selected unlatch process that unlatches the actuator from the magnetic latch.

11. The device of claim 8 further comprising a flex circuit supporting the thermistor, and in which the value of the thermistor is a resistance level of the thermistor, wherein the resistance level of the thermistor is indicative of a temperature adjacent the thermistor.

12. The device of claim 11, in which the temperature adjacent the thermistor is an internal temperature of a head-disc assembly of the data storage device.

13. A storage device combination comprising;

a base deck; and

an actuator supported by the base deck confined by a latch during periods of inactivity, and unlatched from the latch for periods of activity by steps for unlatching the actuator, the steps comprising;

(a) reading a thermistor to determine a value of the thermistor, wherein the value of the thermistor corresponds to the internal temperature of the data storage device;

(b) comparing the value of the thermistor to a predetermined temperature threshold value;

(c) initiating a DC current unlatch process when the value of the thermistor is greater than the predetermined temperature threshold value;

(d) validating success of the DC current unlatch process unlatching the actuator from the latch of the data storage device;

(e) activating an AC current unlatch process when the DC current unlatch process is unsuccessful in unlatching the actuator from the latch of the data storage device; and

in the alternative

(f) commencing the AC current unlatch process when the value of the thermistor is less than the predetermined temperature threshold value.

14. The combination of claim 13, in which the latch is a magnetic latch, and in which the DC unlatch process comprises the steps of:

selecting an initial DC current;

applying the initial DC current across a coil of the actuator for an initial time interval;

measuring a response of the coil to the initially applied DC current;

determining whether the actuator has been successfully unlatched from the magnetic latch based on the response of the coil to the applied current

increasing incrementally the initial DC current to a predetermined maximum DC current level;

measuring the response of the coil to each incremental increase in the initial DC current up to the predetermined maximum DC current level to determine whether the actuator has been successfully unlatched from the magnetic latch;

expanding incrementally the initial time interval to a predetermined maximum time interval when the predetermined maximum DC current level applied across the coil for the initial time interval has been unsuccessful in unlatching of the actuator from the magnetic latch;

evaluating the response of the coil to each incremental increase in the initial time interval up to the predetermined maximum time interval to determine whether the actuator has been successfully unlatched from the magnetic latch; and

switching to the AC current unlatch process when the predetermined maximum DC current level applied across the coil for the predetermined maximum time interval has been unsuccessful in unlatching the actuator from the magnetic latch.

15. The combination of claim 14, in which the AC unlatch process comprises the steps of:

selecting an initial AC current;

applying the initial AC current across a coil of the actuator for a predetermined time interval;

measuring a response of the coil to the initially applied AC current;

determining whether the actuator has been successfully unlatched from the magnetic latch based on the response of the coil to the applied current;

increasing incrementally the initial AC current to a predetermined maximum AC current level;

measuring the response of the coil to each incremental increase in the initial AC current up to the predetermined maximum AC current level to determine whether the actuator has been successfully unlatched from the magnetic latch; and

reporting an unlatch failure upon an unsuccessfully unlatching of the actuator from the magnetic latch.

16. The combination of claim 13, in which the latch is a magnetic latch, and in which the AC unlatch process comprises the steps of:

selecting an initial AC current;

applying the initial AC current across a coil of the actuator for a predetermined time interval;

measuring a response of the coil to the initially applied AC current;

determining whether the actuator has been successfully unlatched from the magnetic latch based on the response of the coil to the applied current;

increasing incrementally the initial AC current to a predetermined maximum AC current level;

measuring the response of the coil to each incremental increase in the initial AC current up to the predetermined maximum AC current level to determine whether the actuator has been successfully unlatched from the magnetic latch; and

reporting an unlatch failure upon an unsuccessfully unlatching of the actuator from the magnetic latch.