Min Ling Chen

US Patent:

7440225, Oct 21, 2008

Filed:

Aug 21, 2006

Appl. No.:

11/507234

Inventors:

Min Chen - San Rafael CA, US
Zhi Wang - Irvine CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 5/596

US Classification:

360 7804, 360 7809

Abstract:

A disk drive is disclosed including a disk having a plurality of servo tracks, wherein each servo track comprises a plurality of servo sectors forming N servo wedges, and a wedge time period (WTP) occurs between each servo wedge. A VCM control signal is generated by generating an estimated WTP by detecting the servo sectors, estimating a pivot velocity in response to the estimated WTP, the pivot velocity representing a velocity of an actuator arm about a pivot, generating a pivot friction compensation in response to the estimated pivot velocity, and generating the VCM control signal in response to the pivot friction compensation.

US Patent:

7589593, Sep 15, 2009

Filed:

Jan 30, 2008

Appl. No.:

12/022159

Inventors:

Jie-Wei Lai - Taipei, TW
Min Chen - Fremont CA, US

Assignee:

Mediatek Inc. - Hsin-Chu

International Classification:

H03F 3/04
H03F 1/22

US Classification:

330295, 330311

Abstract:

An amplifier circuit for amplifying an input signal to generate an output signal is provided. The amplifier circuit has a stacked main amplifier, a parallel sub-amplifier, and a signal combiner. The stacked main amplifier includes a first amplifier unit for outputting a first amplified signal generated from processing the input signal; and a second amplifier unit for outputting a second amplified signal generated from processing the first amplified signal. The first amplifier unit and the second amplifier unit share bias current. The parallel sub-amplifier is coupled to the stacked main amplifier according to a parallel connection fashion, and outputs a third amplified signal generated from processing the input signal. The signal combiner combines the second amplified signal and the third amplified signal to generate the output signal.

US Patent:

7616399, Nov 10, 2009

Filed:

Dec 7, 2006

Appl. No.:

11/635904

Inventors:

Min Chen - San Rafael CA, US
Zhi Wang - Irvine CA, US
Duc T. Phan - Saratoga CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 5/596

US Classification:

360 7708

Abstract:

A disk drive comprising a moveable head, a disk, and a servo controller that implements servo control techniques to preserve PES continuity during track following operations is disclosed. The disk includes a plurality of tracks in which a substantial majority of the tracks include a plurality of servo sectors having a plurality of servo bursts that are utilized in track following operations. The servo controller controls track following operations with the moveable head and implements operations to preserve PES continuity during track following. These operations include: dividing tracks of the disk into a plurality of zones wherein each zone includes zone boundaries; and utilizing a PES equation for each zone to generate a PES value based upon read servo bursts wherein each zone PES equation includes a normalizing factor to account for boundary conditions associated with zone boundaries to preserve PES value continuity between zones.

US Patent:

7675707, Mar 9, 2010

Filed:

Nov 21, 2008

Appl. No.:

12/275989

Inventors:

Min Chen - San Leandro CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 21/02

US Classification:

360 75

Abstract:

A disk drive is disclosed comprising a disk, a head actuated over the disk, and control circuitry operable to generate a fly height control signal. A fly height of the head is measured, and the measured fly height is combined with a target fly height and a feedforward signal, wherein the feedforward signal is generated according to:acos(2πnk/N)+bsin(2πnk/N)where aand bare coefficients and 2πnk/N represents a frequency of a repeatable disturbance in the fly height of the head.

US Patent:

7688538, Mar 30, 2010

Filed:

Nov 16, 2007

Appl. No.:

11/941467

Inventors:

Min Chen - San Leandro CA, US
Duc T. Phan - Saratoga CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 21/02

US Classification:

360 75

Abstract:

A disk drive is disclosed comprising a disk surface having a plurality of servo sectors for defining a plurality of servo tracks, and a head actuated radially over the disk surface. A first servo sector defines a first servo track comprising a first track address having a first width, and a second servo sector defines a second servo track comprising a second track address having a second width substantially less than the first width. In one embodiment the servo sectors are written using an external servo writer or media writer, and in another embodiment the servo sectors are self-servo written by the disk drive.

US Patent:

7961422, Jun 14, 2011

Filed:

Feb 19, 2009

Appl. No.:

12/388644

Inventors:

Min Chen - San Leandro CA, US
Li Yi - Mountain View CA, US
Duc T. Phan - Saratoga CA, US

Assignee:

Western Digital Technologies, Inc. - Irvine CA

International Classification:

G11B 5/596

US Classification:

360 7704, 360 7708

Abstract:

A disk drive is disclosed comprising a disk having a plurality of servo tracks that define a plurality of data tracks, and a head actuated over the disk by a voice coil motor (VCM), wherein the head comprises a read element offset radially from a write element. The read element is positioned over a first servo track and the write element is positioned over a second servo track, and a first repeatable runout (RRO) of the first servo track is measured. The read element is positioned over the second servo track, and a second RRO of the second servo track is measured. A data center off-track is computed in response to the first RRO and the second RRO.

US Patent:

8001733, Aug 23, 2011

Filed:

Dec 4, 2009

Appl. No.:

12/592844

Inventors:

Min Chen - Fremont CA, US

International Classification:

B66F 3/08
E21D 15/00

US Classification:

521264, 254 98, 254 92, 254 93 A, 254100, 521266, 52632, 2483543, 405290

Abstract:

A post adjustable in length as required. The post can be adjusted at any time during and after construction. The post can be used as an extension of a column which requires adjustment in length. The post can be used as a jack. The post is capable of withstanding compression, tension, and dynamic loading. The post can be used to provide support to beams and girders in a house frame.

US Patent:

8077428, Dec 13, 2011

Filed:

Jun 23, 2010

Appl. No.:

12/821360

Inventors:

Min Chen - San Leandro CA, US
Qixing Zheng - Albany CA, US
James V. Wiseman - Palo Alto CA, US

Assignee:

Western Digital Technologies, Inc. - Irvine CA

International Classification:

G11B 21/02

US Classification:

360 75

Abstract:

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors that define a plurality of servo tracks. A position error signal (PES) is generated in response to the servo sectors, and a head velocity is estimated relative to the servo tracks. A correction value is generated as a function of the head velocity and the PES, and the PES is adjusted using the correction value to generate an adjusted PES. The head is positioned over the disk in response to the adjusted PES.