Patents by Inventor Huihao Xu

Huihao Xu 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: 8219041
    Abstract: A design structure embodied in a machine-readable medium used in a design process provides a transmitter having a frequency response controllable in accordance with an operational parameter, and may include a storage operable to store operational parameters for controlling a frequency response of the transmitter under each of a plurality of corresponding operating conditions. A sensor can be used to detect an operating condition. In response to a change in the detected operating condition, a stored operational parameter corresponding to the detected operating condition can be used to control the frequency response of the transmitter.
    Type: Grant
    Filed: November 19, 2007
    Date of Patent: July 10, 2012
    Assignee: International Business Machines Corporation
    Inventors: Louis L. Hsu, Hayden C. Cranford, Jr., Joseph Natonio, James D. Rockrohr, Huihao Xu, Steven J. Zier
  • Patent number: 8219040
    Abstract: A method is provided for operating a transmitter integrated in a microelectronic element. In a calibration phase, a plurality of operational parameters are stored for controlling a frequency response of the transmitter under each of a plurality of corresponding operating conditions. Upon detecting an operating condition such as a temperature or power supply voltage level, the corresponding stored operational parameter is applied to the transmitter to control the frequency response.
    Type: Grant
    Filed: June 27, 2007
    Date of Patent: July 10, 2012
    Assignee: International Business Machines Corporation
    Inventors: Louis L. Hsu, Hayden C. Cranford, Jr., Joseph Natonio, James D. Rockrohr, Huihao Xu, Steven J. Zier
  • Patent number: 8144726
    Abstract: A design structure is provided for a microelectronic serial driver. The serial driver is operable to transmit a differential pattern signal during a burst interval and a predetermined common mode voltage level during a second interval between adjacent burst intervals, the serial driver including at least one pre-driver and a driver coupled to an output of the pre-driver for transmitting the differential communication signal. A switching circuit is operable to switch the serial driver between a first power supply voltage level for the burst interval and the predetermined common mode voltage level, wherein the predetermined common mode voltage level is independent of variations in power supply voltage conditions and temperature conditions.
    Type: Grant
    Filed: May 27, 2008
    Date of Patent: March 27, 2012
    Assignee: International Business Machines Corporation
    Inventors: Huihao Xu, Joseph Natonio, James D. Rockrohr, Michael A. Sorna
  • Patent number: 7974304
    Abstract: An integrated microelectronic serial driver is provided which is operable to transmit a differential pattern signal during a burst interval and a predetermined common mode voltage level during a second interval between adjacent burst intervals, the serial driver including at least one pre-driver and a driver coupled to an output of the pre-driver for transmitting the differential communication signal. A switching circuit is operable to switch the serial driver between a first power supply voltage level for the burst interval and the predetermined common mode voltage level, wherein the predetermined common mode voltage level is independent of variations in power supply voltage conditions and temperature conditions.
    Type: Grant
    Filed: June 7, 2007
    Date of Patent: July 5, 2011
    Assignee: International Business Machines Corporation
    Inventors: Huihao Xu, Joseph Natonio, James D. Rockrohr, Michael A. Sorna
  • Patent number: 7873922
    Abstract: A design structure embodied in a machine-readable medium used in a design process may include a system for detecting a fault in a signal transmission path. Such system may include, for example, a hysteresis comparator including a latch having n-type field effect transistor (“NFET”) storage elements. The hysteresis comparator may be operable to detect a crossing of a reference voltage level by an input signal arriving from the signal transmission path such that when the comparator does not detect an expected crossing of the reference voltage level by the input signal, the fault is determined to be detected in the signal transmission path.
    Type: Grant
    Filed: November 19, 2007
    Date of Patent: January 18, 2011
    Assignee: International Business Machines Corporation
    Inventors: Huihao Xu, Louis L. Hsu, Kevin G. Kramer, James D. Rockrohr, Michael A. Sorna
  • Patent number: 7855563
    Abstract: A system is provided for detecting a fault in a signal transmission path. In one embodiment, the system can include a variable amplitude signal attenuator which is operable to modify an input signal by variably attenuating a signal voltage swing of the input signal. Desirably, the input signal is attenuated only when transitioning from a high signal voltage level towards a low signal voltage level d variably, such that a larger high-to-low signal voltage swing is attenuated more than a smaller high-to-low signal voltage swing. Desirably, a comparator, which may apply hysteresis to the output signals, may detect a crossing of a reference voltage level by the modified input signal. In this way, when the comparator does not detect an expected crossing of the reference voltage level by the modified input signal, a determination can be made that a fault exists in the signal transmission path.
    Type: Grant
    Filed: June 21, 2007
    Date of Patent: December 21, 2010
    Assignee: International Business Machines Corporation
    Inventors: Huihao Xu, Louis L. Hsu, Kevin G. Kramer, James D. Rockrohr, Michael A. Sorna
  • Patent number: 7733964
    Abstract: In a method for performing equalization of a communication system, a predetermined signal can be transmitted from a transmitter unit to a receiver unit in a downchannel direction on a transmission line, for example as a pair of differential signals which simultaneously transition in opposite directions on respective signal conductors of the transmission line. At the receiver unit, an eye opening of the signal received from the transmission line can be analyzed to determine equalization information. Equalization information can be transmitted from the receiver unit to the transmitter unit in an upchannel direction on the transmission line and be received at the transmitter unit. Using received equalization information, a transmission characteristic of the transmitter unit can be adjusted.
    Type: Grant
    Filed: October 17, 2007
    Date of Patent: June 8, 2010
    Assignee: International Business Machines Corporation
    Inventors: Louis L. Hsu, Karl D. Selander, Michael A. Sorna, Jeremy K. Stephens, Huihao Xu
  • Patent number: 7694243
    Abstract: A system for protecting a weak device operating in micro-electronic circuit and a design structure including the system embodied in a machine readable medium are disclosed. The system includes a high voltage power supply from high voltage overstressing prevents the weak device from failing during power-up, power-down, and when a low voltage power supply in a multiple power supply system is absent. The system further includes a low voltage power supply detection circuit configured to detect circuit power-up, circuit power-down, and when the low voltage power supply is absent, and generate a control signal upon detection. The system further includes a controlled current mirror device configured to provide a trickle current to maintain a conduction channel in the weak device in response to the control signal received from the low voltage power supply detection circuit during circuit power-up, circuit power-down, and when the low voltage power supply is absent.
    Type: Grant
    Filed: December 27, 2007
    Date of Patent: April 6, 2010
    Assignee: International Business Machines Corporation
    Inventors: Hibourahima Camara, Louis C. Hsu, James D. Rockrohr, Karl D. Selander, Huihao Xu, Steven J. Zier
  • Patent number: 7659740
    Abstract: Digital testing of an analog driver circuit is enabled using a circuit including a control circuit for generating signals, a differential driver circuit for receiving a differential input signal, amplifying the differential input signal and transmitting a differential output signal, a programmable termination impedance circuit for generating a differential termination impedance at the output node of the differential driver circuit, and a differential receiver circuit for converting the differential output signal to a single ended signal and transmitting the single ended signal.
    Type: Grant
    Filed: August 11, 2008
    Date of Patent: February 9, 2010
    Assignee: International Business Machines Corporation
    Inventors: Joseph O. Marsh, Jeremy Stephens, Charlie C. Hwang, James S. Mason, Huihao Xu, Matthew B. Baecher, Thomas J. Bardsley, Mark R. Taylor
  • Publication number: 20090300562
    Abstract: A design structure is provided for a microelectronic serial driver. The serial driver is operable to transmit a differential pattern signal during a burst interval and a predetermined common mode voltage level during a second interval between adjacent burst intervals, the serial driver including at least one pre-driver and a driver coupled to an output of the pre-driver for transmitting the differential communication signal. A switching circuit is operable to switch the serial driver between a first power supply voltage level for the burst interval and the predetermined common mode voltage level, wherein the predetermined common mode voltage level is independent of variations in power supply voltage conditions and temperature conditions.
    Type: Application
    Filed: May 27, 2008
    Publication date: December 3, 2009
    Inventors: Huihao Xu, Joseph Natonio, James D. Rockrohr, Michael A. Sorna
  • Publication number: 20090172614
    Abstract: A system for protecting a weak device operating in micro-electronic circuit and a design structure including the system embodied in a machine readable medium are disclosed. The system includes a high voltage power supply from high voltage overstressing prevents the weak device from failing during power-up, power-down, and when a low voltage power supply in a multiple power supply system is absent. The system further includes a low voltage power supply detection circuit configured to detect circuit power-up, circuit power-down, and when the low voltage power supply is absent, and generate a control signal upon detection. The system further includes a controlled current mirror device configured to provide a trickle current to maintain a conduction channel in the weak device in response to the control signal received from the low voltage power supply detection circuit during circuit power-up, circuit power-down, and when the low voltage power supply is absent.
    Type: Application
    Filed: December 27, 2007
    Publication date: July 2, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Hibourahima Camara, Louis C. Hsu, James D. Rockrohr, Karl D. Selander, Huihao Xu, Steven J. Zier
  • Publication number: 20090129485
    Abstract: A design structure embodied in a machine-readable medium used in a design process provides a transmitter having a frequency response controllable in accordance with an operational parameter, and may include a storage operable to store operational parameters for controlling a frequency response of the transmitter under each of a plurality of corresponding operating conditions. A sensor can be used to detect an operating condition. In response to a change in the detected operating condition, a stored operational parameter corresponding to the detected operating condition can be used to control the frequency response of the transmitter.
    Type: Application
    Filed: November 19, 2007
    Publication date: May 21, 2009
    Inventors: Louis L. Hsu, Hayden C. Cranford, JR., Joseph Natonio, James D. Rockrohr, Huihao Xu, Steven J. Zier
  • Publication number: 20090128161
    Abstract: A design structure embodied in a machine-readable medium used in a design process may include a system for detecting a fault in a signal transmission path. Such system may include, for example, a hysteresis comparator including a latch having n-type field effect transistor (“NFET”) storage elements. The hysteresis comparator may be operable to detect a crossing of a reference voltage level by an input signal arriving from the signal transmission path such that when the comparator does not detect an expected crossing of the reference voltage level by the input signal, the fault is determined to be detected in the signal transmission path.
    Type: Application
    Filed: November 19, 2007
    Publication date: May 21, 2009
    Inventors: Huihao Xu, Louis L. Hsu, Kevin G. Kramer, James D. Rockrohr, Michael A. Sorna
  • Patent number: 7519130
    Abstract: A data receiver is provided which includes a front end interface circuit having an alternating current (AC) transmission receiving mode and a direct current (DC) transmission receiving mode. The front end interface circuit includes an offset compensation circuit operable to compensate a DC voltage offset between a pair of differential signals input to the data receiver. The front end interface circuit further includes an AC/DC selection unit operable to switch between (a) the DC transmission receiving mode, and (b) the AC transmission receiving mode, such that the data receiver is operable in (i) the DC transmission mode in which the offset compensation circuit is disabled, (ii) the DC transmission mode in which the offset compensation circuit is enabled, (iii) the AC transmission mode in which the offset compensation circuit is disabled, and (iv) the AC transmission receiving mode in which the offset compensation circuit is enabled.
    Type: Grant
    Filed: January 18, 2005
    Date of Patent: April 14, 2009
    Assignee: International Business Machines Corporation
    Inventors: Louis L. Hsu, Matt R. Cordrey-Gale, James S. Mason, Philip J. Murfet, Karl D. Selander, Michael A. Sorna, Huihao Xu
  • Publication number: 20090027075
    Abstract: A circuit and method of testing an analog driver circuit using digital scan-based test methodologies. The circuit of the present invention comprises a control circuit for generating signals in response to a test enable signal, a differential driver circuit for receiving a differential input signal, amplifying the differential input signal and transmitting a differential output signal in response to the differential input signal and the signals generated by the control circuit, a programmable termination impedance circuit for generating a differential termination impedance at the output node of the differential driver circuit in response the signals generated by the control circuit, and a differential receiver circuit for receiving the differential output from the differential driver circuit, convert the differential output signal to a single ended signal and transmitting the single ended signal, all in response to the test enable signal.
    Type: Application
    Filed: August 11, 2008
    Publication date: January 29, 2009
    Applicant: International Business Machines Corporation
    Inventors: Joseph O. Marsh, Jeremy Stephens, Charlie C. Hwang, James S. Mason, Huihao Xu, Matthew B. Baecher, Thomas J. Bardsley, Mark R. Taylor
  • Publication number: 20090004978
    Abstract: A method is provided for operating a transmitter integrated in a microelectronic element. In a calibration phase, a plurality of operational parameters are stored for controlling a frequency response of the transmitter under each of a plurality of corresponding operating conditions. Upon detecting an operating condition such as a temperature or power supply voltage level, the corresponding stored operational parameter is applied to the transmitter to control the frequency response.
    Type: Application
    Filed: June 27, 2007
    Publication date: January 1, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Louis L. Hsu, Hayden C. Cranford, Jr., Joseph Natonio, James D. Rockrohr, Huihao Xu, Steven J. Zier
  • Publication number: 20080316930
    Abstract: A system is provided for detecting a fault in a signal transmission path. In one embodiment, the system can include a variable amplitude signal attenuator which is operable to modify an input signal by variably attenuating a signal voltage swing of the input signal. Desirably, the input signal is attenuated only when transitioning from a high signal voltage level towards a low signal voltage level d variably, such that a larger high-to-low signal voltage swing is attenuated more than a smaller high-to-low signal voltage swing. Desirably, a comparator, which may apply hysteresis to the output signals, may detect a crossing of a reference voltage level by the modified input signal. In this way, when the comparator does not detect an expected crossing of the reference voltage level by the modified input signal, a determination can be made that a fault exists in the signal transmission path.
    Type: Application
    Filed: June 21, 2007
    Publication date: December 25, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Huihao Xu, Louis L. Hsu, Kevin G. Kramer, James D. Rockrohr, Michael A. Sorna
  • Patent number: 7466156
    Abstract: A circuit of testing an analog driver circuit using digital scan-based test methodologies. The circuit of the present invention includes a control circuit for generating signals in response to a test enable signal, a differential driver circuit for receiving a differential input signal, amplifying the differential input signal and transmitting a differential output signal in response to the differential input signal and the signals generated by the control circuit, a programmable termination impedance circuit for generating a differential termination impedance at the output node of the differential driver circuit in response the signals generated by the control circuit, and a differential receiver circuit for receiving the differential output from the differential driver circuit, convert the differential output signal to a single ended signal and transmitting the single ended signal, all in response to the test enable signal.
    Type: Grant
    Filed: March 25, 2004
    Date of Patent: December 16, 2008
    Assignee: International Business Machines Corporation
    Inventors: Joseph O. Marsh, Jeremy Stephens, Charlie C. Hwang, James S. Mason, Huihao Xu, Matthew B. Baecher, Thomas J. Bardsley, Mark R. Taylor
  • Publication number: 20080304509
    Abstract: An integrated microelectronic serial driver is provided which is operable to transmit a differential pattern signal during a burst interval and a predetermined common mode voltage level during a second interval between adjacent burst intervals, the serial driver including at least one pre-driver and a driver coupled to an output of the pre-driver for transmitting the differential communication signal. A switching circuit is operable to switch the serial driver between a first power supply voltage level for the burst interval and the predetermined common mode voltage level, wherein the predetermined common mode voltage level is independent of variations in power supply voltage conditions and temperature conditions.
    Type: Application
    Filed: June 7, 2007
    Publication date: December 11, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Huihao Xu, Joseph Natonio, James D. Rockrohr, Michael A. Sorna
  • Publication number: 20080137721
    Abstract: In a method for performing equalization of a communication system, a predetermined signal can be transmitted from a transmitter unit to a receiver unit in a downchannel direction on a transmission line, for example as a pair of differential signals which simultaneously transition in opposite directions on respective signal conductors of the transmission line. At the receiver unit, an eye opening of the signal received from the transmission line can be analyzed to determine equalization information. Equalization information can be transmitted from the receiver unit to the transmitter unit in an upchannel direction on the transmission line and be received at the transmitter unit. Using received equalization information, a transmission characteristic of the transmitter unit can be adjusted.
    Type: Application
    Filed: October 17, 2007
    Publication date: June 12, 2008
    Inventors: Louis L. Hsu, Karl D. Selander, Michael A. Sorna, Jeremy K. Stephens, Huihao Xu