Patents by Inventor Ji Zhao

Ji Zhao 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: 6650188
    Abstract: A two-stage coupling loop system that provides in-phase and quadrature signals in the two stages. Each stage includes a signal coupler, an LC-based voltage controlled oscillator (VCO) and an in-loop signal buffer that provides an additional controllable phase shift. Inclusion of the buffers in the loop decreases the capacitance load of each VCO.
    Type: Grant
    Filed: December 2, 2002
    Date of Patent: November 18, 2003
    Assignee: Lattice Semiconductor Corporation
    Inventors: Edwin Chan, Ming Qu, Ji Zhao
  • Patent number: 6614291
    Abstract: A signal multiplexer system and a signal latch system for low voltage (Vdd≈1.2 volts) and high speed transitions between states. A dc signal isolation circuit, inserted between a clock signal circuit and a signal input/output circuit, allows use of a two-transistor-layer vertical structure that provides adequate headroom voltage (about 0.3-0.4 volts, or larger) for high speed transistor response.
    Type: Grant
    Filed: June 15, 2001
    Date of Patent: September 2, 2003
    Assignee: Lattice Semiconductor Corp.
    Inventors: Ji Zhao, Kochung Lee, Edwin Chan
  • Patent number: 6525617
    Abstract: A two-stage ring oscillator system that provides a phase shift of 90° in each of the two stages. Each stage includes an LC-based stage including a voltage controlled oscillator (VCO) and an in-line signal buffer that provides an additional controllable phase shift in the forward path and reduces loading capacitance of each LC-based stage by an estimated 10-50 percent. In-phase and quadrature output signals are provided by the system.
    Type: Grant
    Filed: August 9, 2001
    Date of Patent: February 25, 2003
    Assignee: Lattice Semiconductor Corporation
    Inventors: Edwin Chan, Ming Qu, Ji Zhao
  • Patent number: 6498538
    Abstract: System and method for providing low noise signal having a broad tuning range (1 GHz to 10 GHz, or larger), with associated jitter no more than about 10 percent of the selected period of a target output signal. In a first stage, a ring-based VCO phase locked loop system provides a broad tuning range with some associated noise, and a second stage in a first state is relatively transparent, with no substantial differential attenuation based on frequency. After phase lock is achieved, the second stage is switched to a second state with low associated noise and high differential attenuation based on input signal frequency.
    Type: Grant
    Filed: May 30, 2001
    Date of Patent: December 24, 2002
    Assignee: Lattice Semiconductor Corporation
    Inventors: Ming Qu, Ji Zhao
  • Patent number: 6492877
    Abstract: A two-stage coupling loop system that provides in-phase and quadrature signals in two stages. Each stage includes a signal coupler, an LC-based voltage controlled oscillator (VCO) and in-loop signal buffer that provides an additional controllable phase shift. Inclusion of the buffers in the loop decreases the capacitance load of each VCO.
    Type: Grant
    Filed: August 9, 2001
    Date of Patent: December 10, 2002
    Assignee: Lattice Semiconductor Corporation
    Inventors: Edwin Chan, Ming Qu, Ji Zhao
  • Patent number: 6429692
    Abstract: A data sampling system, including a data tracking circuit and a data latching circuit, that reduces the likelihood of metastability that arises through competition of the two circuits, where data sampling occurs in a transition time interval. A combined latching and weakened tracking circuit is provided in which the tracking operation cannot change an output signal from the latching operation after the latch resolves a valid logical state.
    Type: Grant
    Filed: June 19, 2001
    Date of Patent: August 6, 2002
    Assignee: Octillion Communications, Inc.
    Inventors: Edwin Chan, Kochung Lee, Ji Zhao
  • Patent number: 6146958
    Abstract: Disclosed are methods of making inductors and capacitors, comprising filling a via in a dielectric disposed between two metal layers with a metal plug. The plug comprises tungsten, aluminum or copper and extends the length of the metal layers. The plug connects the two metal layers to form the inductor. Two plugs can be formed so as to connect the two metal layers so as to form a parallel plate capacitor.
    Type: Grant
    Filed: September 22, 1998
    Date of Patent: November 14, 2000
    Assignee: National Semiconductor Corporation
    Inventors: Ji Zhao, Chih Sieh Teng
  • Patent number: 5861647
    Abstract: Disclosed are methods of making inductors and capacitors, comprising filling a via in a dielectric disposed between two metal layers with a metal plug. The plug comprises tungsten, aluminum or copper and extends the length of the metal layers. The plug connects the two metal layers to form the inductor. Two plugs can be formed so as to connect the two metal layers so as to form a parallel plate capacitor.
    Type: Grant
    Filed: October 2, 1996
    Date of Patent: January 19, 1999
    Assignee: National Semiconductor Corporation
    Inventors: Ji Zhao, Chih Sieh Teng