Patents by Inventor Songtao Xu

Songtao 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: 9401711
    Abstract: A circuit of an output stage of a push-pull driver having dynamic biasing may include a stacked configuration of field effect transistors (PFETs) having a first PFET, a second PFET, and a third PFET, whereby the first PFET is connected to a first supply voltage, the third PFET is connected to an output of a switchable voltage bias generator circuit, and the second PFET is electrically connected between the first PFET and the third PFET. A transmission gate may be connected to a second supply voltage, whereby the transmission gate electrically connects the second supply voltage to an electrical connection between the first PFET and the second PFET based on a first operating state for preventing a voltage breakdown condition associated with the stacked configuration of PFETs. The third PFET is bias controlled via the switching of the output of the switchable voltage bias generator circuit.
    Type: Grant
    Filed: November 14, 2014
    Date of Patent: July 26, 2016
    Assignee: International Business Machines Corporation
    Inventors: Francis Chan, Bo Qu, Si Shi, Songtao Xu
  • Publication number: 20160142051
    Abstract: A circuit of an output stage of a push-pull driver having dynamic biasing may include a stacked configuration of field effect transistors (PFETs) having a first PFET, a second PFET, and a third PFET, whereby the first PFET is connected to a first supply voltage, the third PFET is connected to an output of a switchable voltage bias generator circuit, and the second PFET is electrically connected between the first PFET and the third PFET. A transmission gate may be connected to a second supply voltage, whereby the transmission gate electrically connects the second supply voltage to an electrical connection between the first PFET and the second PFET based on a first operating state for preventing a voltage breakdown condition associated with the stacked configuration of PFETs. The third PFET is bias controlled via the switching of the output of the switchable voltage bias generator circuit.
    Type: Application
    Filed: November 14, 2014
    Publication date: May 19, 2016
    Inventors: Francis Chan, Bo Qu, Si Shi, Songtao Xu
  • Publication number: 20090027124
    Abstract: An analog level-shifting buffer for providing signal amplitude and/or common mode adjustment is disclosed. In one example, a receiver system may include a first amplification stage that is powered, for example, via an I/O power supply (e.g., VDDIO) and a second amplification stage that is powered, for example, via a core logic power supply (e.g., VDD). Arranged between the first and second amplification stages may be the analog level-shifting buffer. The analog level-shifting buffer may include a set of variable impedance elements for controlling the output common mode and output signal swing of the level-shifting buffer.
    Type: Application
    Filed: September 30, 2008
    Publication date: January 29, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventor: Songtao Xu
  • Patent number: 7463078
    Abstract: An analog level-shifting differential amplifier for providing signal amplitude and/or common mode adjustment is disclosed. In one example, a receiver system may include a first amplification stage that is powered, for example, via an I/O power supply (e.g., VDDIO) and a second amplification stage that is powered, for example, via a core logic power supply (e.g., VDD). Arranged between the first and second amplification stages may be the analog level-shifting differential amplifier. The analog level-shifting differential amplifier may include a set of variable impedance elements for controlling the output common mode and output signal swing of the level-shifting differential amplifier.
    Type: Grant
    Filed: January 15, 2007
    Date of Patent: December 9, 2008
    Assignee: International Business Machines Corporation
    Inventor: Songtao Xu
  • Publication number: 20080169875
    Abstract: An analog level-shifting buffer for providing signal amplitude and/or common mode adjustment is disclosed. In one example, a receiver system may include a first amplification stage that is powered, for example, via an I/O power supply (e.g., VDDIO) and a second amplification stage that is powered, for example, via a core logic power supply (e.g., VDD). Arranged between the first and second amplification stages may be the analog level-shifting buffer. The analog level-shifting buffer may include a set of variable impedance elements for controlling the output common mode and output signal swing of the level-shifting buffer.
    Type: Application
    Filed: January 15, 2007
    Publication date: July 17, 2008
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventor: Songtao Xu
  • Patent number: 6784703
    Abstract: In order to reduce slew rate and minimize delay skew, the invention adds a pull-down booster circuit connected to the gate of the driving transistor and/or a pull-up booster circuit connected the gate of the driving transistor. The pull-down booster circuit is adapted to dynamically pull-down the voltage at the gate of the driving transistor when the voltage level at the input to the logical enable device changes from a first voltage (e.g., a logical “0”) to a second voltage (e.g., a logical “1”). The pull-up booster circuit is adapted to dynamically pull-up the voltage at the gate of the driving transistor when the voltage level at the input to the logical enable device changes from the second voltage to the first voltage.
    Type: Grant
    Filed: June 30, 2003
    Date of Patent: August 31, 2004
    Assignee: International Business Machines Corporation
    Inventors: Jason Chung, Hongfei Wu, Songtao Xu