Patents by Inventor Hongliang Chang

Hongliang Chang 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: 8762908
    Abstract: In one embodiment of the invention, a method of analysis of a circuit design with respect to within-die process variation is disclosed to generate a design-specific on chip variation (DS-OCV) de-rating factor. The method includes executing a static timing analysis (STA) in an on-chip variation mode using a process corner library. Collecting timing information of the top N critical timing paths. Executing a statistical static timing analysis (SSTA) on the N critical timing paths using timing models characterized for SSTA with sensitivities of delays to process variables. Compare the two timing results and deriving DS-OCV de-rating factors for the clock/data paths to be used in a STA OCV timing analysis to correctly account for the effects of process variations. A user may select to specify DS-OCV de-rating factors for paths or groups of paths and achieve an accurate timing analysis report in a reduced amount of run-time.
    Type: Grant
    Filed: June 27, 2010
    Date of Patent: June 24, 2014
    Assignee: Cadence Design Systems, Inc.
    Inventors: Hongliang Chang, Vassilios Gerousis, Sireesha Molakalapalli, Sachin Shrivastava
  • Patent number: 8336010
    Abstract: In one embodiment of the invention, a method of analysis of a circuit design with respect to within-die process variation is disclosed to generate a design-specific on chip variation (DS-OCV) de-rating factor. The method includes executing a static timing analysis (STA) in an on-chip variation mode using a process corner library. Collecting timing information of the top N critical timing paths. Executing a statistical static timing analysis (SSTA) on the N critical timing paths using timing models characterized for SSTA with sensitivities of delays to process variables. Compare the two timing results and deriving DS-OCV de-rating factors for the clock/data paths to be used in a STA OCV timing analysis to correctly account for the effects of process variations. A user may select to specify DS-OCV de-rating factors for paths or groups of paths and achieve an accurate timing analysis report in a reduced amount of run-time.
    Type: Grant
    Filed: June 27, 2010
    Date of Patent: December 18, 2012
    Assignee: Cadence Design Systems, Inc.
    Inventors: Hongliang Chang, Vassilios Gerousis, Sireesha Molakalapalli, Sachin Shrivastava
  • Patent number: 8151229
    Abstract: A system and method for determining the criticality of each timing pin in a circuit design are disclosed. The criticality of a timing pin is the probability that the timing pin is on the path with the worst slack in the circuit design. According to the methodology, the slack for each timing pin is calculated, wherein each slack is a function of a process random variable. Then, the criticality of each timing pin is determined as the probability of the timing pin having the minimum slack among the slacks in an independent critical set of timing pins. The criticality of each timing pin may then be normalized. By determining the criticalities of the timing pins in a circuit design, a circuit design system may be able to more easily identify portions of the circuit design that need modification for timing and other purposes.
    Type: Grant
    Filed: April 10, 2007
    Date of Patent: April 3, 2012
    Assignee: Cadence Design Systems, Inc.
    Inventors: Hongliang Chang, Oleg Levitsky, Nikolay Rubanov, Vassilios Gerousis
  • Patent number: 8086978
    Abstract: A method, system, and computer program product are disclosed for performing statistical leakage power characterization to estimate yield of a circuit in terms of leakage power. According to some approaches, this is performed with consideration of state correlation.
    Type: Grant
    Filed: June 20, 2008
    Date of Patent: December 27, 2011
    Assignee: Cadence Design Systems, Inc.
    Inventors: Lizheng Zhang, Parveen Khurana, Vassilios Gerousis, Hongliang Chang, Sachin Shrivastava
  • Patent number: 8069432
    Abstract: A method, system, and computer program product are disclosed for performing statistical leakage power characterization to estimate yield of a circuit in terms of leakage power. According to some approaches, this is performed with consideration of bi-exponential modeling.
    Type: Grant
    Filed: September 30, 2008
    Date of Patent: November 29, 2011
    Assignee: Cadence Design Systems, Inc.
    Inventors: Lizheng Zhang, Hongliang Chang, Kai-Ti Huang, Vassilios Gerousis
  • Patent number: 8015525
    Abstract: There is provided a system and method for statistical timing analysis and optimization of an electrical circuit having two or more digital elements. The system includes at least one parameter input and a statistical static timing analyzer and electrical circuit optimizer. The at least one parameter input is for receiving parameters of the electrical circuit. At least one of the parameters has at least one of a non-Gaussian probability distribution and a non-linear delay effect. The statistical static timing analyzer and electrical circuit optimizer is for calculating at least one of a signal arrival time and a signal required time for the electrical circuit using the at least one parameter and for modifying a component size of the electrical circuit to alter gate timing characteristics of the electrical circuit based upon the at least one of the signal arrival time and the signal required time.
    Type: Grant
    Filed: May 2, 2008
    Date of Patent: September 6, 2011
    Assignee: International Business Machines Corporation
    Inventors: Hongliang Chang, Sambasivan Narayan, Chandramouli Visweswariah, Vladimir Zolotov
  • Publication number: 20100083198
    Abstract: A method, system, and computer program product are disclosed for performing statistical leakage power characterization to estimate yield of a circuit in terms of leakage power. According to some approaches, this is performed with consideration of bi-exponential modeling.
    Type: Application
    Filed: September 30, 2008
    Publication date: April 1, 2010
    Inventors: Lizheng Zhang, Hongliang Chang, Kai-Ti Huang, Vassilios Gerousis
  • Publication number: 20090319969
    Abstract: A method, system, and computer program product are disclosed for performing statistical leakage power characterization to estimate yield of a circuit in terms of leakage power. According to some approaches, this is performed with consideration of state correlation.
    Type: Application
    Filed: June 20, 2008
    Publication date: December 24, 2009
    Inventors: Lizheng Zhang, Parveen Khurana, Vassilios Gerousis, Hongliang Chang, Sachin Shrivastava
  • Publication number: 20080201676
    Abstract: There is provided a system and method for statistical timing analysis and optimization of an electrical circuit having two or more digital elements. The system includes at least one parameter input and a statistical static timing analyzer and electrical circuit optimizer. The at least one parameter input is for receiving parameters of the electrical circuit. At least one of the parameters has at least one of a non-Gaussian probability distribution and a non-linear delay effect. The statistical static timing analyzer and electrical circuit optimizer is for calculating at least one of a signal arrival time and a signal required time for the electrical circuit using the at least one parameter and for modifying a component size of the electrical circuit to alter gate timing characteristics of the electrical circuit based upon the at least one of the signal arrival time and the signal required time.
    Type: Application
    Filed: May 2, 2008
    Publication date: August 21, 2008
    Inventors: Hongliang Chang, Sambasivan Narayan, Chandramouli Visweswariah, Vladimir Zolotov
  • Patent number: 7293248
    Abstract: There is provided a system and method for statistical timing analysis of an electrical circuit. The system includes at least one parameter input, a statistical static timing analyzer, and at least one output. The at least one parameter input is for receiving parameters of the electrical circuit. At least one of the parameters has at least one of a non-Gaussian probability distribution and a non-linear delay effect. The statistical static timing analyzer is for calculating at least one of a signal arrival time and a signal required time for the electrical circuit using the at least one parameter. The at least one output is for outputting the at least one of the signal arrival time and the signal required time.
    Type: Grant
    Filed: February 11, 2005
    Date of Patent: November 6, 2007
    Assignee: International Business Machines Corporation
    Inventors: Hongliang Chang, Sambasivan Narayan, Chandramouli Visweswariah, Vladimir Zolotov
  • Publication number: 20070234256
    Abstract: There is provided a system and method for statistical timing analysis and optimization of an electrical circuit having two or more digital elements. The system includes at least one parameter input and a statistical static timing analyzer and electrical circuit optimizer. The at least one parameter input is for receiving parameters of the electrical circuit. At least one of the parameters has at least one of a non-Gaussian probability distribution and a non-linear delay effect. The statistical static timing analyzer and electrical circuit optimizer is for calculating at least one of a signal arrival time and a signal required time for the electrical circuit using the at least one parameter and for modifying a component size of the electrical circuit to alter gate timing characteristics of the electrical circuit based upon the at least one of the signal arrival time and the signal required time.
    Type: Application
    Filed: June 13, 2007
    Publication date: October 4, 2007
    Inventors: HONGLIANG CHANG, Sambasivan Narayan, Chandramouli Visweswariah, Vladimir Zolotov
  • Publication number: 20060085775
    Abstract: There is provided a system and method for statistical timing analysis of an electrical circuit. The system includes at least one parameter input, a statistical static timing analyzer, and at least one output. The at least one parameter input is for receiving parameters of the electrical circuit. At least one of the parameters has at least one of a non-Gaussian probability distribution and a non-linear delay effect. The statistical static timing analyzer is for calculating at least one of a signal arrival time and a signal required time for the electrical circuit using the at least one parameter. The at least one output is for outputting the at least one of the signal arrival time and the signal required time.
    Type: Application
    Filed: February 11, 2005
    Publication date: April 20, 2006
    Inventors: Hongliang Chang, Sambasivan Narayan, Chandramouli Visweswariah, Vladimir Zolotov