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: 7332956
    Abstract: A system for protecting a weak device operating in micro-electronic circuit that includes a high voltage power supply from high voltage over stressing 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 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: October 27, 2005
    Date of Patent: February 19, 2008
    Assignee: International Business Machines Corporation
    Inventors: Hibourahima Camara, Louis C. Hsu, James D. Rockrohr, Karl D. Selander, Huihao Xu, Steven J. Zier
  • Patent number: 7295618
    Abstract: A data communication system includes a transmitter unit and a receiver unit. The transmission unit has a transmission characteristic that is adjustable in accordance with equalization information. The transmission unit is operable to transmit a predetermined signal and the receiver unit is operable to receive the predetermined signal. The receiver unit is further operable to generate the equalization information by examining the eye opening of the received signal, and to transmit the equalization information to the transmitter unit.
    Type: Grant
    Filed: June 16, 2004
    Date of Patent: November 13, 2007
    Assignee: International Business Machines Corporation
    Inventors: Louis L. Hsu, Karl D. Selander, Michael A. Sorna, Jeremy K. Stephens, Huihao Xu
  • Publication number: 20070096797
    Abstract: A system for protecting a weak device operating in micro-electronic circuit that 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 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: October 27, 2005
    Publication date: May 3, 2007
    Applicant: INTERNATIONAL BUSINESS MACHINES COPORATION
    Inventors: Hibourahima Camara, Louis Hsu, James Rockrohr, Karl Selander, Huihao Xu, Steven Zier
  • Publication number: 20060159200
    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: Application
    Filed: January 18, 2005
    Publication date: July 20, 2006
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Louis Hsu, Matt Cordrey-Gale, James Mason, Phillip Murfet, Karl Selander, Michael Sorna, Huihao Xu
  • Publication number: 20050281343
    Abstract: A data communication system includes a transmitter unit and a receiver unit. The transmission unit has a transmission characteristic that is adjustable in accordance with equalization information. The transmission unit is operable to transmit a predetermined signal and the receiver unit is operable to receive the predetermined signal. The receiver unit is further operable to generate the equalization information by examining the eye opening of the received signal, and to transmit the equalization information to the transmitter unit.
    Type: Application
    Filed: June 16, 2004
    Publication date: December 22, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Louis Hsu, Karl Selander, Michael Sorna, Jeremy Stephens, Huihao Xu
  • Publication number: 20050246125
    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: March 25, 2004
    Publication date: November 3, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Joseph Marsh, Jeremy Stephens, Charlie Hwang, James Mason, Huihao Xu, Matthew Baecher, Thomas Bardsley, Mark Taylor
  • Publication number: 20050190828
    Abstract: A system and method of detecting a fault in a transmission link are provided which includes providing a selectable reference level according to one of a direct current (DC) mode threshold and an alternating current (AC) mode threshold, wherein the DC mode threshold is a fixed potential and the AC mode threshold varies with time. An input signal arriving from the transmission link is compared to one of the DC mode threshold and the AC mode threshold to determine whether a fault is present in the transmission link.
    Type: Application
    Filed: February 27, 2004
    Publication date: September 1, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Louis Hsu, Harry Linzer, James Rockrohr, Huihao Xu