Patents by Inventor WeiSung Lee
WeiSung Lee has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20120044593Abstract: One way to minimize full DC head-skew re-calibrations rendered necessary by changes in storage media drive operating temperature is to compensate for temperature-induced DC head-skew using a known relationship between temperature-induced DC head-skew and storage media operating temperature. More specifically, a first DC head-skew is measured at a first arbitrary temperature of the storage media drive. A second DC head-skew is measured at a second arbitrary temperature of the storage media drive. A DC head-skew correction factor is calculated using the first and second DC head-skews at the first and second arbitrary temperatures. When a multi-head storage media drive is powered-up for operation, a temperature sensor located in the storage media drive assembly measures the current storage media drive temperature. The head-skew correction factor is applied based on the measured temperature to correct the DC head-skew.Type: ApplicationFiled: August 20, 2010Publication date: February 23, 2012Applicant: Seagate Technology LLCInventors: Yong Xiao, Qiang Bi, Weisung Lee, Mingzhong Ding, Kiankeong Ooi
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Patent number: 7872827Abstract: Various embodiments of the present invention are generally directed to protecting a device from damage due to an impact event at the conclusion of a free fall condition through the use of a biasing signal that maintains a retention force until the impact event is completed.Type: GrantFiled: July 27, 2007Date of Patent: January 18, 2011Assignee: Seagate Technology LLCInventors: JiaHong Shu, TzeMing Jimmy Pang, WeiSung Lee, KianKeong Ooi, KianSoon Yeo, Xiong Liu
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Publication number: 20090027798Abstract: Various embodiments of the present invention are generally directed to protecting a device from damage due to an impact event at the conclusion of a free fall condition through the use of a biasing signal that maintains a retention force until the impact event is completed.Type: ApplicationFiled: July 27, 2007Publication date: January 29, 2009Applicant: Seagate Technology LLCInventors: JiaHong Shu, TzeMing Jimmy Pang, WeiSung Lee, KianKeong Ooi, KianSoon Yeo, Xiong Liu
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Patent number: 7242546Abstract: A location within a cycle is determined by reading a portion of a cyclic bit sequence, the bit sequence containing several interspersed bit-group sets that each contain a plurality of series that each consist of several consecutively-placed identical bit-groups. On a data surface in a disc drive, each bit group can be stored and accessed in unused bits of each servo sector's digital portion.Type: GrantFiled: October 13, 2003Date of Patent: July 10, 2007Assignee: Seagate Technology LLCInventors: KianKeong Ooi, WingKong Chiang, MingZhong Ding, WeiSung Lee, EikFun Khor, BengWee Quak
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Patent number: 6882497Abstract: Track closure errors written into servo sectors of an information track of a disc of a disc drive are resolved from a position control signal generated by a servo control circuit of a data storage device by steps comprising: determining a value for the track closure error from a position error signal, establishing a track closure profile based on the value of the track closure error, and injecting the track profile into the servo control circuit as a feed forward compensation input for the position error signal to resolve the track closure error from the position control signal.Type: GrantFiled: March 4, 2002Date of Patent: April 19, 2005Assignee: Seagate Technology LLCInventors: ShuangQuan Min, KianKeong Ooi, WeiSung Lee, WingKong Chiang
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Publication number: 20050078396Abstract: A location within a cycle is determined by reading a portion of a cyclic bit sequence, the bit sequence containing several interspersed bit-group sets that each contain a plurality of series that each consist of several consecutively-placed identical bit-groups. On a data surface in a disc drive, each bit group can be stored and accessed in unused bits of each servo sector's digital portion.Type: ApplicationFiled: October 13, 2003Publication date: April 14, 2005Inventors: KianKeong Ooi, WingKong Chiang, MingZhong Ding, WeiSung Lee, EikFun Khor, BengWee Quak
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Patent number: 6785073Abstract: Written-in runout due to vibration of the cage of a spindle motor of a disc drive is detected by identifying an initial cage frequency value of the motor. A written-in magnitude of successive servo burst closures, D(nc), is read over a plurality of tracks, and a maximum servo burst closure D(ncp) is identified from the plurality of read servo bursts. A magnitude of the cage frequency at a servo sector n0 is calculated based on a difference between the read magnitudes of the servo burst closures at servo sectors nc and nc+1, and a phase of the cage frequency is calculated based on the magnitude of the written-in cage frequency at servo sector n0. The profile, in the form of cage frequency, maximum servo burst closure magnitude, and initial phase, is stored in a memory or table for each of a plurality of radial zones of tracks. The profile is combined with a position error signal and applied to the controller in a feed forward scheme to adjust the position of the head based on the written-in runout.Type: GrantFiled: April 27, 2001Date of Patent: August 31, 2004Assignee: Seagate Technology LLCInventors: ShuangQuan Min, KianKeon Ooi, YangQuan Chen, Ricky Wei Watt Yeo, WeiSung Lee, BengWee Quak
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Publication number: 20030218814Abstract: Written-in runout due to vibration of the cage of a spindle motor of a disc drive is detected by identifying an initial cage frequency value of the motor. A written-in magnitude of successive servo burst closures, D(nc), is read over a plurality of tracks, and a maximum servo burst closure D(ncp) is identified from the plurality of read servo bursts. A magnitude of the cage frequency at a servo sector n0 is calculated based on a difference between the read magnitudes of the servo burst closures at servo sectors nc and nc+1, and a phase of the cage frequency is calculated based on the magnitude of the written-in cage frequency at servo sector n0. The profile, in the form of cage frequency, maximum servo burst closure magnitude, and initial phase, is stored in a memory or table for each of a plurality of radial zones of tracks. The profile is combined with a position error signal and applied to the controller in a feed forward scheme to adjust the position of the head based on the written-in runout.Type: ApplicationFiled: April 27, 2001Publication date: November 27, 2003Inventors: ShuangQuan Min, KianKeong Ooi, YangQuan Chen, Ricky Wei Watt Yeo, WeiSung Lee, BengWee Quak
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Patent number: 6654198Abstract: Steps for isolating and correcting total written-in repeatable run-out error written into servo sectors of a disc drive include, determining a total repeatable run-out error value for each servo sector, isolating a repeatable error value component of the total written-in repeatable run-out error value for each servo sector, removing the repeatable error value component from total written-in repeatable run-out error value to provide a non-repeatable error value component of the total written-in repeatable run-out error value for each servo sector, providing both the repeatable and non-repeatable error value components to a processor for generation of compensation signals, and applying the compensation signals into a servo control circuit of control loop of the disc drive using compensation circuits to compensate for each component of the total written-in repeatable run-out error.Type: GrantFiled: June 19, 2001Date of Patent: November 25, 2003Assignee: Seagate Technology LLCInventors: Xiong Liu, Kian Keong Ooi, ChoonKiat Lim, Yangquan Chen, Qiang Bi, Mingzhong Ding, ShuangQuan Min, WeiSung Lee
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Publication number: 20030058570Abstract: Track closure errors written into servo sectors of an information track of a disc of a disc drive are resolved from a position control signal generated by a servo control circuit of a data storage device by steps comprising: determining a value for the track closure error from a position error signal, establishing a track closure profile based on the value of the track closure error, and injecting the track profile into the servo control circuit as a feed forward compensation input for the position error signal to resolve the track closure error from the position control signal.Type: ApplicationFiled: March 4, 2002Publication date: March 27, 2003Applicant: Seagate Technology LLCInventors: ShuangQuan Min, KianKeong Ooi, WeiSung Lee, WingKong Chiang
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Publication number: 20020044370Abstract: Written-in runout due to vibration of the cage of a spindle motor of a disc drive is detected by identifying an initial cage frequency value of the motor. A written-in magnitude of successive servo burst closures, D(nc), is read over a plurality of tracks, and a maximum servo burst closure D(ncp) is identified from the plurality of read servo bursts. A magnitude of the cage frequency at a servo sector n0 is calculated based on a difference between the read magnitudes of the servo burst closures at servo sectors nc and nc+1, and a phase of the cage frequency is calculated based on the magnitude of the written-in cage frequency at servo sector n0. The profile, in the form of cage frequency, maximum servo burst closure magnitude, and initial phase, is stored in a memory or table for each of a plurality of radial zones of tracks. The profile is combined with a position error signal and applied to the controller in a feed forward scheme to adjust the position of the head based on the written-in runout.Type: ApplicationFiled: April 27, 2001Publication date: April 18, 2002Inventors: ShuangQuan Min, KianKeon Ooi, YangQuan Chen, Ricky Wei Watt Yeo, WeiSung Lee, BengWee Quak
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Publication number: 20020039248Abstract: Steps for isolating and correcting total written-in repeatable run-out error written into servo sectors of a disc drive include, determining a total repeatable run-out error value for each servo sector, isolating a repeatable error value component of the total written-in repeatable run-out error value for each servo sector, removing the repeatable error value component from total written-in repeatable run-out error value to provide a non-repeatable error value component of the total written-in repeatable run-out error value for each servo sector, providing both the repeatable and non-repeatable error value components to a processor for generation of compensation signals, and applying the compensation signals into a servo control circuit of control loop of the disc drive using compensation circuits to compensate for each component of the total written-in repeatable run-out error.Type: ApplicationFiled: June 19, 2001Publication date: April 4, 2002Applicant: SEAGATE TECHNOLOGY LLCInventors: Xiong Liu, Kian Keong Ooi, ChoonKiat Lim, Yangquan Chen, Qiang Bi, Mingzhong Ding, ShuangQuan Min, WeiSung Lee