Patents by Inventor John Contreras

John Contreras 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).

  • Patent number: 9280993
    Abstract: A method, apparatus, and system for implementing enhanced asymmetric degauss control for a write head for hard disk drives. A degauss period is provided at the end of a write. The write head is driven asymmetrically with respect to the positive and negative driving currents during the degauss period. The average value of the write current during the degauss period is non-zero.
    Type: Grant
    Filed: December 12, 2013
    Date of Patent: March 8, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Zhen Jin, Yuanpeng Li, Xiaoyu Sui
  • Patent number: 9275656
    Abstract: Disk drives with a Channel System and Write Driver Preamp architecture that dynamically adjusts the write driver's signal wave-shape depending on the write data signal pattern are described. The wave-shape control signal is generated in the Channel and transmitted to the Write Driver Preamp. Embodiments of the invention provide discrete n-level overshoot amplitude control using amplitude-level modulated (AML) signal. One embodiment implements a look-ahead strategy overshoot amplitude control where the overshoot amplitude for each transition depends only on the subsequent (following) bits in the data stream and not on any previously recorded data.
    Type: Grant
    Filed: July 20, 2015
    Date of Patent: March 1, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Samir Y. Garzon, Weldon Mark Hanson, Alexander Taratorin
  • Patent number: 9275664
    Abstract: A flex cable with a shielding layer for use in a disk drive is described. The flex cable connects the actuator to the system electronics. The flex cable has a shielding layer that provides RF shielding for the embedded signal traces. In embodiments the shielding layer is connected to the baseplate or device enclosure ground at one or more selected points on the bracket end of the flex cable that are separated from the signal paths. Embodiments of the shielding layer include rows of apertures or windows that are aligned with selected signal traces such as the read and write signal traces and serve to maintain the desired impedance in the read and write signal traces. In one embodiment the shielding layer extends over a selected portion of the flex cable that includes the bracket end and the area under the first stiffener.
    Type: Grant
    Filed: December 13, 2013
    Date of Patent: March 1, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Nobumasa Nishiyama, Albert Wallash
  • Patent number: 9218822
    Abstract: Interconnect and preamplifier designs are described for use in a disk drive with a common signal return lead system that interconnects a plurality of read transducers (readers) in a slider through the suspension to the preamplifier mounted on the actuator. Preamplifier embodiments have an isolated differential amplifier for each of the plurality of readers in the slider. The set of signal traces in the suspension include a common signal return lead for the plurality of readers in the slider. A preamplifier circuit design according to an embodiment of the invention includes isolated amplifiers for each reader with a separate bias source and power supply isolation elements for both power supply polarities for reduced crosstalk signal and noise between amplifiers.
    Type: Grant
    Filed: May 13, 2015
    Date of Patent: December 22, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Samir Y. Garzon, Rehan Ahmed Zakai
  • Patent number: 9196266
    Abstract: An interconnect between the read/write circuitry and the read/write head in a magnetic recording hard disk drive (HDD) for two-dimensional magnetic recording (TDMR) has the read sensor signal lines located on a lower level of a bi-level structure of conductive lines. Common return lines are located on an upper level above the signal lines and on the lower level between the signal lines. All of the return lines on the upper level are connected to one another by cross-connect lines, and vias are located along the interconnect and connect the upper return lines with the lower return lines and with the ground plane of the interconnect's electrically conductive substrate. The interconnect is a coaxial-like interconnect because the return lines are located around each signal line and thus shield each signal line from the other signal lines, much like the outer conductive shield of a coaxial cable.
    Type: Grant
    Filed: July 25, 2014
    Date of Patent: November 24, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Albert John Wallash, Rehan Ahmed Zakai
  • Patent number: 9165596
    Abstract: A disk drive has multiple preamplifiers (preamps) connected to the system-on-a-chip (SOC) by a common transmission line with resistors between the preamps and the SOC. Each preamp includes a read resistor at the output of each read amplifier, and a write resistor at the input of each write driver. The resistors may be programmable resistors located in the preamps. The read resistors are at the source of the signal to the transmission line and the write resistors are at the termination of the signal from the transmission line. The read and write resistors provide impendence matching with the transmission line and the SOC when one of the preamps is selected as active, which enables the SOC to operate seamlessly with a common transmission line connected to all preamps.
    Type: Grant
    Filed: March 13, 2015
    Date of Patent: October 20, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Nobumasa Nishiyama, Joey Martin Poss, Tuyen Van Trinh, Craig K. Yanagisawa, Yasunori Kubo
  • Patent number: 9153248
    Abstract: A disk drive preamplifier (preamp) includes a write driver that has two pairs of programmable bypass current sources not connected to the write current source to compensate for the inherent magnetic asymmetry of the write head. One pair of the programmable bypass current sources provides a fixed bypass current in one direction. The other pair provides a fixed bypass current in the opposite direction. Prior to writing, only one of the pairs of bypass current sources is selected and programmed with the correct value of bypass current. When the write driver generates the positive and negative write current pulses during writing the selected bypass current sources provide a fixed offset to the amplitude of the write current pulses.
    Type: Grant
    Filed: February 25, 2015
    Date of Patent: October 6, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Zhihao Li, Joey Martin Poss
  • Patent number: 9117469
    Abstract: A “split-substrate” design is described for the metal ground layer in the suspension for a slider for use in a disk drive that reduces crosstalk from signals being transmitted on the conductive traces and allows externally induced interference to be shunted away from sensitive traces along selected portions of the suspension. In embodiments of the invention a slit formed in the metal ground layer to provide two parallel ground paths respectively on the left and right sides of the selected portion of the suspension. By positioning interference signal generating traces like writer traces on one side of the slit, that side becomes the noisy ground path leaving the other side as a “quiet” ground path. The shape, positioning and grounding of the split substrate structure can shunt return/ground currents created by external RFI into the noisy leg and thereby shield the quiet leg.
    Type: Grant
    Filed: December 1, 2014
    Date of Patent: August 25, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Albert John Wallash, Rehan Ahmed Zakai
  • Patent number: 9117474
    Abstract: A method, apparatus, and system are provided for implementing a write head device for writer-to-disk contact detection and spacing sensing of recording heads in hard disk drives (HDDs). A write head device, such as a spin-torque oscillator (STO), is provided between a main pole tip and a surrounding magnetic shield of the writer in the recording head. A pair of connections is provided to the magnetic shield and the main pole of the writer, and resistance of the write head device is measured to detect writer to disk spacing and contact.
    Type: Grant
    Filed: October 2, 2014
    Date of Patent: August 25, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Samir Y. Garzon, Timothy Scott Hughbanks, Albert John Wallash
  • Patent number: 9111561
    Abstract: A disk drive dynamic wave shaper (DWS) write driver includes a write current generator that produces a baseline output current for the write current pulses and an overshoot current generator that produces an overshoot current with different values. The overshoot current is added to the baseline current, with the value of the overshoot current amplitude (OSA) being selected in response to the frequency of transitions in the write data signal. The write driver includes logic circuitry that detects the pattern of transitions. Transitions that are immediately followed by a transition will receive a larger-than-nominal OSA1, transitions that are not immediately followed by a transition and that are not preceded by a long sequence of non-transitions will receive a nominal OSA2, and transitions after longer sequences of non-transitions will receive a smaller-than-nominal OSA3.
    Type: Grant
    Filed: October 28, 2014
    Date of Patent: August 18, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Samir Y. Garzon, Weldon Mark Hanson, Rehan Ahmed Zakai
  • Patent number: 9099128
    Abstract: A method, apparatus, and system are provided for implementing noise based detection of spin-torque oscillator (STO) power on for microwave assisted magnetic recording (MAMR) hard disk drives (HDDs). A low frequency noise generated by a spin-torque oscillator, such as noise in a frequency range between 10 kHz and 100 MHz, is detected. The detected STO noise is compared to a predefined threshold to identify STO power on operation.
    Type: Grant
    Filed: October 28, 2014
    Date of Patent: August 4, 2015
    Assignee: HGST Netherlands BV
    Inventors: John Contreras, Samir Y. Garzon, Rehan Ahmed Zakai
  • Publication number: 20150170690
    Abstract: A flex cable with a shielding layer for use in a disk drive is described. The flex cable connects the actuator to the system electronics. The flex cable has a shielding layer that provides RF shielding for the embedded signal traces. In embodiments the shielding layer is connected to the baseplate or device enclosure ground at one or more selected points on the bracket end of the flex cable that are separated from the signal paths. Embodiments of the shielding layer include rows of apertures or windows that are aligned with selected signal traces such as the read and write signal traces and serve to maintain the desired impedance in the read and write signal traces. In one embodiment the shielding layer extends over a selected portion of the flex cable that includes the bracket end and the area under the first stiffener.
    Type: Application
    Filed: December 13, 2013
    Publication date: June 18, 2015
    Inventors: John Contreras, Nobumasa Nishiyama, Albert Wallash
  • Publication number: 20150170687
    Abstract: A method, apparatus, and system for implementing enhanced asymmetric degauss control for a write head for hard disk drives. A degauss period is provided at the end of a write. The write head is driven asymmetrically with respect to the positive and negative driving currents during the degauss period. The average value of the write current during the degauss period is non-zero.
    Type: Application
    Filed: December 12, 2013
    Publication date: June 18, 2015
    Applicant: HGST Netherlands B.V.
    Inventors: John Contreras, Zhen Jin, Yuanpeng Li, Xiaoyu Sui
  • Patent number: 9036306
    Abstract: A flexible cable assembly (FCA) has a stiffener layer positioned in electrical contact with an electrical ground feature of the FCA, and a head stack assembly (HSA) may include a suspension tail electrically connected to the stiffener layer of the FCA, thus providing a robust ground path between the read/write head and the arm or E-block of the HSA. Additional efficient grounding techniques may include directly electrically connecting the suspension tail to the arm via a conductive adhesive, directly electrically connecting the FCA stiffener layer to the arm via a conductive screw, and/or directly electrically connecting the ground feature and the stiffener layer of the FCA to the arm using a ground post or screw.
    Type: Grant
    Filed: December 19, 2013
    Date of Patent: May 19, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Nobumasa Nishiyama, Yuji Soga, Kazuhiro Nagaoka, John Contreras, Albert Wallash
  • Patent number: 9001444
    Abstract: A method, apparatus, and system are provided for implementing a power-on spin-torque oscillator (STO) oscillation checker to monitor STO resistance to identify STO oscillation with microwave assisted magnetic recording (MAMR) hard disk drives (HDDs). An amplitude modulated write coil drive current is applied to the write coil in the presence of a DC bias current applied to the STO. The amplitude modulated write coil drive current modulates the STO resistance monitored using an amplifier circuit to identify STO oscillation, used to ensure stable MAMR HDD write operation.
    Type: Grant
    Filed: June 26, 2014
    Date of Patent: April 7, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Samir Y. Garzon, Rehan Ahmed Zakai
  • Patent number: 8988829
    Abstract: Disk drive embodiments with common lead connections in the slider, suspension, and preamplifier are described. The arm electronics IC includes a preamplifier with single-ended input from the set of signal traces that include a common signal return lead for the plurality of read transducers (readers) in the slider. Two embodiments of the preamps are described that include a single-ended design and a pseudo-single-ended design. Each embodiment supplies the required bias to each read transducer using an operational transconductance amplifier (OTA) that drives a variable current source connected to the transducer. The positive input to the OTA is a DC voltage with the AC signal from the transducer imposed on it. The negative input is a DC reference voltage. Various embodiments of the signal trace configuration on the suspension are described including a single and double layer embodiments.
    Type: Grant
    Filed: September 18, 2014
    Date of Patent: March 24, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Joey Martin Poss, Rehan Ahmed Zakai
  • Publication number: 20150077879
    Abstract: Disk drive embodiments with common lead connections in the slider, suspension, and preamplifier are described. The arm electronics IC includes a preamplifier with single-ended input from the set of signal traces that include a common signal return lead for the plurality of read transducers (readers) in the slider. Two embodiments of the preamps are described that include a single-ended design and a pseudo-single-ended design. Each embodiment supplies the required bias to each read transducer using an operational transconductance amplifier (OTA) that drives a variable current source connected to the transducer. The positive input to the OTA is a DC voltage with the AC signal from the transducer imposed on it. The negative input is a DC reference voltage. Various embodiments of the signal trace configuration on the suspension are described including a single and double layer embodiments.
    Type: Application
    Filed: September 18, 2014
    Publication date: March 19, 2015
    Inventors: John Contreras, Joey Martin Poss, Rehan Ahmed Zakai
  • Patent number: 8982504
    Abstract: A method, apparatus, and system for implementing calibration of cooling sensitivity of embedded contact sensor (ECS) using thermal fly-height control (TFC) actuations, by subtracting the linear part (TFC heat) from the total measured ECS signal, a profile is provided that is sensitive only to the clearance of the head-disk interface due to cooling effect for hard disk drives.
    Type: Grant
    Filed: December 10, 2013
    Date of Patent: March 17, 2015
    Assignee: HGST Netherlands BV
    Inventors: John Contreras, Saurabh Deoras, Samir Garzon, Remmelt Pit, Craig K. Yanagisawa
  • Patent number: 8917465
    Abstract: A method, apparatus, and system are provided for implementing a power-on spin-torque oscillator (STO) oscillation checker to monitor STO resistance to identify STO oscillation with microwave assisted magnetic recording (MAMR) hard disk drives (HDDs). A changing bias current is applied to the STO in the presence of constant write drive current. The STO bias current is changed to observe sudden changes in STO resistance monitored using a differentiator circuit to identify STO oscillation, used to ensure stable MAMR HDD write operation.
    Type: Grant
    Filed: June 26, 2014
    Date of Patent: December 23, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Samir Y. Garzon, Ikuya Tagawa, Rehan Ahmed Zakai
  • Patent number: 8891189
    Abstract: Disk drives with sliders including with an impedance compensation network in the signal path for the read sensor are described. The read signal bandwidth at the preamplifier is improved by the impedance compensation network to allow signals in the multi-GHz range from spin torque oscillators as well as tunnel magnetoresistance (TMR) sensors to be used. An embodiment of the invention achieves a signal layout balance by constructing two inductor-capacitor pair structures on the trailing edge of the slider that are integrated into the differential read signal traces. The differential balanced structure helps to suppress external signal interference pick-up from transferring from common-mode pick-up to differential mode.
    Type: Grant
    Filed: March 18, 2014
    Date of Patent: November 18, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: John Contreras, Samir Y. Garzon, Bruce Alvin Gurney, David John Seagle