Patents by Inventor Mohammad Mortazavi

Mohammad Mortazavi 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: 7647220
    Abstract: A high accuracy method for transistor-level static timing analysis is disclosed. Accurate static timing verification requires that individual gate and interconnect delays be accurately calculated. At the sub-micron level, calculating gate and interconnect delays using delay models can result in reduced accuracy. Instead, the proposed method calculates delays through numerical integration using an embedded circuit simulator. It takes into account short circuit current and carefully chooses the set of conditions that results in a tight upper bound of the worst case delay for each gate. Similar repeating transistor configurations of gates in the circuit are automatically identified and a novel interpolation based caching scheme quickly computes gate delays from the delays of similar gates. A tight object code level integration with a commercial high speed transistor-level circuit simulator allows efficient invocation of the simulation.
    Type: Grant
    Filed: October 18, 2001
    Date of Patent: January 12, 2010
    Assignee: Cadence Design Systems, Inc.
    Inventors: Pawan Kulshreshtha, Robert J. Palermo, Mohammad Mortazavi, Cyrus Bamji, Hakan Yalcin
  • Patent number: 6877143
    Abstract: A computer-implemented method abstracts the timing constraints for latches internal to a digital logic circuit, resulting in a clock characterization model. Timing information (such as propagation delays, set-up and hold requirements) for latches and combinational logic circuits contained in a digital logic circuit are received, as is a description of a class of clock scheme for clocking the circuit. Clock parameters are selected for the clock scheme class. The internal timing constraints for the digital logic circuit are expressed as timing constraint expressions which are a function of the clock parameters. The expressions are combined to define a region of feasible clock operation expressed in terms of the clock parameters.
    Type: Grant
    Filed: August 23, 2002
    Date of Patent: April 5, 2005
    Assignee: Cadence Design Systems, Inc.
    Inventors: Robert J Palermo, Karem A. Sakallah, Shekaripuram V. Venkatesh, Mohammad Mortazavi
  • Publication number: 20030115035
    Abstract: A high accuracy method for transistor-level static timing analysis is disclosed. Accurate static timing verification requires that individual gate and interconnect delays be accurately calculated. At the sub-micron level, calculating gate and interconnect delays using delay models can result in reduced accuracy. Instead, the proposed method calculates delays through numerical integration using an embedded circuit simulator. It takes into account short circuit current and carefully chooses the set of conditions that results in a tight upper bound of the worst case delay for each gate. Similar repeating transistor configurations of gates in the circuit are automatically identified and a novel interpolation based caching scheme quickly computes gate delays from the delays of similar gates. A tight object code level integration with a commercial high speed transistor-level circuit simulator allows efficient invocation of the simulation.
    Type: Application
    Filed: October 18, 2001
    Publication date: June 19, 2003
    Inventors: Pawan Kulshreshtha, Robert J. Palermo, Mohammad Mortazavi, Cyrus Bamji, Hakan Yalcin
  • Patent number: 6442739
    Abstract: A computer-implemented method abstracts the timing constraints for latches internal to a digital logic circuit, resulting in a clock characterization model. Timing information (such as propagation delays, set-up and hold requirements) for latches and combinational logic circuits contained in a digital logic circuit are received, as is a description of a class of clock scheme for clocking the circuit. Clock parameters are selected for the clock scheme class. The internal timing constraints for the digital logic circuit are expressed as timing constraint expressions which are a function of the clock parameters. The expressions are combined to define a region of feasible clock operation expressed in terms of the clock parameters.
    Type: Grant
    Filed: December 17, 1998
    Date of Patent: August 27, 2002
    Assignee: Cadence Design Systems, Inc.
    Inventors: Robert J. Palermo, Karem A. Sakallah, Shekaripuram V. Venkatesh, Mohammad Mortazavi
  • Patent number: 5753145
    Abstract: This invention provides novel liquid crystalline polymers which, when blended with a suitable dye at a suitable high temperature and extruded, yields polarizer films with superior thermal and hygroscopic stability and polarizing efficiency. The invention further provides a process to prepare such polarizer films.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: May 19, 1998
    Assignee: Hoecst Celanese Corp.
    Inventors: Chia-Chi Teng, Hyun Nam Yoon, Mohammad Mortazavi
  • Patent number: 5672296
    Abstract: This invention provides novel liquid crystalline polymers which, when mixed with a suitable dye and extruded, yields polarizer films with superior polarizing efficiency, transmittance, dichroic ratio, and thermal and humidity stability. The invention further provides a process to prepare such polymers and polarizer films therefrom.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: September 30, 1997
    Assignee: Hoechst Celanese Corp.
    Inventors: Sunny S. Shen, Hyun Nam Yoon, Mohammad Mortazavi
  • Patent number: 5667719
    Abstract: This invention provides all organic high extinction polarizers based on blends of novel liquid crystalline polymers and suitable dichroic dyes. The invention further provides a process to prepare such polarizer films.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: September 16, 1997
    Assignee: Hoechst Celanese Corp.
    Inventors: Mohammad Mortazavi, Hyun Nam Yoon, Chia-Chi Teng
  • Patent number: 5400172
    Abstract: There is disclosed and claim a multi-layer polymeric optical element including at least two poled film members exhibiting nonlinear optical susceptibility. The films may be poled in an ordinary atmosphere under relatively mild conditions, or corona poled at high voltage. The elements are particularly useful for periodic or quasi-random optical applications such as parametric amplification of light or frequency doubling.
    Type: Grant
    Filed: March 18, 1993
    Date of Patent: March 21, 1995
    Assignee: Hoechst Celanese Corp.
    Inventors: Garo Khanarian, Mohammad A. Mortazavi