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).
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Patent number: 8219040Abstract: 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: GrantFiled: June 27, 2007Date of Patent: July 10, 2012Assignee: International Business Machines CorporationInventors: Louis L. Hsu, Hayden C. Cranford, Jr., Joseph Natonio, James D. Rockrohr, Huihao Xu, Steven J. Zier
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Patent number: 8219041Abstract: 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: GrantFiled: November 19, 2007Date of Patent: July 10, 2012Assignee: International Business Machines CorporationInventors: Louis L. Hsu, Hayden C. Cranford, Jr., Joseph Natonio, James D. Rockrohr, Huihao Xu, Steven J. Zier
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Patent number: 8144726Abstract: 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: GrantFiled: May 27, 2008Date of Patent: March 27, 2012Assignee: International Business Machines CorporationInventors: Huihao Xu, Joseph Natonio, James D. Rockrohr, Michael A. Sorna
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Patent number: 7974304Abstract: 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: GrantFiled: June 7, 2007Date of Patent: July 5, 2011Assignee: International Business Machines CorporationInventors: Huihao Xu, Joseph Natonio, James D. Rockrohr, Michael A. Sorna
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Patent number: 7873922Abstract: 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: GrantFiled: November 19, 2007Date of Patent: January 18, 2011Assignee: International Business Machines CorporationInventors: Huihao Xu, Louis L. Hsu, Kevin G. Kramer, James D. Rockrohr, Michael A. Sorna
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Patent number: 7855563Abstract: 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: GrantFiled: June 21, 2007Date of Patent: December 21, 2010Assignee: International Business Machines CorporationInventors: Huihao Xu, Louis L. Hsu, Kevin G. Kramer, James D. Rockrohr, Michael A. Sorna
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Patent number: 7733964Abstract: 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: GrantFiled: October 17, 2007Date of Patent: June 8, 2010Assignee: International Business Machines CorporationInventors: Louis L. Hsu, Karl D. Selander, Michael A. Sorna, Jeremy K. Stephens, Huihao Xu
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Patent number: 7694243Abstract: 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: GrantFiled: December 27, 2007Date of Patent: April 6, 2010Assignee: International Business Machines CorporationInventors: Hibourahima Camara, Louis C. Hsu, James D. Rockrohr, Karl D. Selander, Huihao Xu, Steven J. Zier
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Patent number: 7659740Abstract: 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: GrantFiled: August 11, 2008Date of Patent: February 9, 2010Assignee: International Business Machines CorporationInventors: Joseph O. Marsh, Jeremy Stephens, Charlie C. Hwang, James S. Mason, Huihao Xu, Matthew B. Baecher, Thomas J. Bardsley, Mark R. Taylor
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Publication number: 20090300562Abstract: 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: ApplicationFiled: May 27, 2008Publication date: December 3, 2009Inventors: Huihao Xu, Joseph Natonio, James D. Rockrohr, Michael A. Sorna
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Publication number: 20090172614Abstract: 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: ApplicationFiled: December 27, 2007Publication date: July 2, 2009Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Hibourahima Camara, Louis C. Hsu, James D. Rockrohr, Karl D. Selander, Huihao Xu, Steven J. Zier
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Publication number: 20090129485Abstract: 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: ApplicationFiled: November 19, 2007Publication date: May 21, 2009Inventors: Louis L. Hsu, Hayden C. Cranford, JR., Joseph Natonio, James D. Rockrohr, Huihao Xu, Steven J. Zier
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Publication number: 20090128161Abstract: 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: ApplicationFiled: November 19, 2007Publication date: May 21, 2009Inventors: Huihao Xu, Louis L. Hsu, Kevin G. Kramer, James D. Rockrohr, Michael A. Sorna
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Patent number: 7519130Abstract: 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: GrantFiled: January 18, 2005Date of Patent: April 14, 2009Assignee: International Business Machines CorporationInventors: Louis L. Hsu, Matt R. Cordrey-Gale, James S. Mason, Philip J. Murfet, Karl D. Selander, Michael A. Sorna, Huihao Xu
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Publication number: 20090027075Abstract: 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: ApplicationFiled: August 11, 2008Publication date: January 29, 2009Applicant: International Business Machines CorporationInventors: Joseph O. Marsh, Jeremy Stephens, Charlie C. Hwang, James S. Mason, Huihao Xu, Matthew B. Baecher, Thomas J. Bardsley, Mark R. Taylor
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Publication number: 20090004978Abstract: 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: ApplicationFiled: June 27, 2007Publication date: January 1, 2009Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Louis L. Hsu, Hayden C. Cranford, Jr., Joseph Natonio, James D. Rockrohr, Huihao Xu, Steven J. Zier
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Publication number: 20080316930Abstract: 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: ApplicationFiled: June 21, 2007Publication date: December 25, 2008Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Huihao Xu, Louis L. Hsu, Kevin G. Kramer, James D. Rockrohr, Michael A. Sorna
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Patent number: 7466156Abstract: 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: GrantFiled: March 25, 2004Date of Patent: December 16, 2008Assignee: International Business Machines CorporationInventors: Joseph O. Marsh, Jeremy Stephens, Charlie C. Hwang, James S. Mason, Huihao Xu, Matthew B. Baecher, Thomas J. Bardsley, Mark R. Taylor
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Publication number: 20080304509Abstract: 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: ApplicationFiled: June 7, 2007Publication date: December 11, 2008Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Huihao Xu, Joseph Natonio, James D. Rockrohr, Michael A. Sorna
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Publication number: 20080137721Abstract: 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: ApplicationFiled: October 17, 2007Publication date: June 12, 2008Inventors: Louis L. Hsu, Karl D. Selander, Michael A. Sorna, Jeremy K. Stephens, Huihao Xu