Patents by Inventor Xudong Shi

Xudong Shi 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).

  • Publication number: 20070200603
    Abstract: A PLL/DLL circuit is current self-biased responsive to a current Ild provided from a voltage regulator to a VCO or VCDL. Bias current Ibias, which is proportional to Ild, is provided to components of the PLL/DLL, such as a charge pump or loop resistor, from an interconnect coupled to the voltage regulator. In an embodiment of the present invention, a component of the PLL/DLL includes a bias-generating device, such as a MOSFET p-type transistor having a drain coupled to the interconnect. In an embodiment of the present invention, a voltage regulator includes an AMP having a bias-generating device, such as a p-type transistor, acting as a current source, having a source coupled to Vdd and a drain coupled to the interconnect. The gate of the bias-generating device is coupled to the gate of four other p-type devices. Each of the four p-type devices has a source coupled to Vdd. The drains of the first and second p-type transistors are coupled to an output providing Ild.
    Type: Application
    Filed: May 2, 2007
    Publication date: August 30, 2007
    Applicant: RAMBUS INC.
    Inventors: Xudong Shi, Kun-Yung Chang
  • Patent number: 7026848
    Abstract: A pre-driver circuit for use in high speed signaling systems is disclosed. In one particular exemplary embodiment, the pre-driver circuit may comprise an input transistor, an active load, a passive load, and a current source. The input transistor has a gate terminal, a current sinking terminal, and a current sourcing terminal. The active load has a control input coupled to the gate terminal of the input transistor, a current sourcing terminal coupled to the current sinking terminal of the input transistor, and a current sinking terminal. The passive load has a first terminal coupled to the current sinking terminal of the active load and a second terminal coupled to the current sourcing terminal of the active load. The current source is coupled to the current sourcing terminal of the input transistor.
    Type: Grant
    Filed: May 18, 2004
    Date of Patent: April 11, 2006
    Assignee: Rambus Inc.
    Inventors: Yueyong Wang, Xudong Shi
  • Publication number: 20050258875
    Abstract: A pre-driver circuit for use in high speed signaling systems is disclosed. In one particular exemplary embodiment, the pre-driver circuit may comprise an input transistor, an active load, a passive load, and a current source. The input transistor has a gate terminal, a current sinking terminal, and a current sourcing terminal. The active load has a control input coupled to the gate terminal of the input transistor, a current sourcing terminal coupled to the current sinking terminal of the input transistor, and a current sinking terminal. The passive load has a first terminal coupled to the current sinking terminal of the active load and a second terminal coupled to the current sourcing terminal of the active load. The current source is coupled to the current sourcing terminal of the input transistor.
    Type: Application
    Filed: May 18, 2004
    Publication date: November 24, 2005
    Inventors: Yueyong Wang, Xudong Shi
  • Publication number: 20050068073
    Abstract: A PLL/DLL circuit is current self-biased responsive to a current Ild provided from a voltage regulator to a VCO or VCDL. Bias current Ibias, which is proportional to Ild, is provided to components of the PLL/DLL, such as a charge pump or loop resistor, from an interconnect coupled to the voltage regulator. In an embodiment of the present invention, a component of the PLL/DLL includes a bias-generating device, such as a MOSFET p-type transistor having a drain coupled to the interconnect. In an embodiment of the present invention, a voltage regulator includes an AMP having a bias-generating device, such as a p-type transistor, acting as a current source, having a source coupled to Vdd and a drain coupled to the interconnect. The gate of the bias-generating device is coupled to the gate of four other p-type devices. Each of the four p-type devices has a source coupled to Vdd. The drains of the first and second p-type transistors are coupled to an output providing Ild.
    Type: Application
    Filed: February 3, 2004
    Publication date: March 31, 2005
    Inventors: Xudong Shi, Kun-Yung Chang
  • Patent number: 5926049
    Abstract: A low power line driver uses a dynamic biasing scheme together with single ended architecture to achieve low power, fast speed and high return loss. The line driver includes a first and second operation amplifier each having an output port for generating an output pulse signal having a rising and falling edge. The load is coupled to the first and second output port by a transformer. A first and second digital control circuit is coupled to the first and second operational amplifiers to control the operational amplifiers. The first and second operational amplifiers further include a pulse circuit for generating the output pulse signal and a selectable current source having a first mode for injecting a high current to the pulse circuit to provide a high slew rate for the rising edge of the output pulse signal and a second mode for injecting a second current to the pulse circuit during the generation of the remaining portion of the output pulse signal.
    Type: Grant
    Filed: April 11, 1997
    Date of Patent: July 20, 1999
    Assignee: Level One Communications, Inc.
    Inventor: Xudong Shi