Patents by Inventor Peivand Fallah-Tehrani

Peivand Fallah-Tehrani 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: 9424380
    Abstract: A system and a method are disclosed for performing static timing analysis. Information describing a distorted input waveform is received by a static timing analyzer. A transition time of the distorted input waveform is determined. Based on the determined input transition time a nominal input waveform and a corresponding nominal output waveform are received. An input waveform distortion is computed based on the nominal input waveform and the distorted input waveform. An output waveform distortion is computed based on an augmented circuit and the input waveform distortion. A distorted output waveform is computed based on the nominal output waveform and the output waveform distortion. The waveforms are represented using the distortion values which are smaller than the actual waveform values, thereby allowing for compact representation. A time-shifted version of an uncoupled input waveform is used to perform conservative timing analysis of circuits that accounts for crosstalk in the circuit.
    Type: Grant
    Filed: September 5, 2014
    Date of Patent: August 23, 2016
    Assignee: Synopsys, Inc.
    Inventors: Jiayong Le, Peivand Fallah Tehrani, Li Ding, Xin Wang, Ahmed Shebaita
  • Publication number: 20160070834
    Abstract: A system and a method are disclosed for performing static timing analysis. Information describing a distorted input waveform is received by a static timing analyzer. A transition time of the distorted input waveform is determined. Based on the determined input transition time a nominal input waveform and a corresponding nominal output waveform are received. An input waveform distortion is computed based on the nominal input waveform and the distorted input waveform. An output waveform distortion is computed based on an augmented circuit and the input waveform distortion. A distorted output waveform is computed based on the nominal output waveform and the output waveform distortion. The waveforms are represented using the distortion values which are smaller than the actual waveform values, thereby allowing for compact representation. A time-shifted version of an uncoupled input waveform is used to perform conservative timing analysis of circuits that accounts for crosstalk in the circuit.
    Type: Application
    Filed: September 5, 2014
    Publication date: March 10, 2016
    Inventors: Jiayong Le, Peivand Fallah Tehrani, Li Ding, Xin Wang, Ahmed Shebaita
  • Patent number: 8924906
    Abstract: A computer-implemented method of determining an attribute of a circuit includes using a computationally expensive technique to simulate the attribute (such as timing delay or slew) of a portion of the circuit, at predetermined values of various parameters (e.g. nominal values of channel length or metal width), to obtain at least a first value of the attribute. The method also uses a computationally inexpensive technique to estimate the same attribute, thereby to obtain at least a second value which is less accurate than the first value. Then the computationally inexpensive technique is repeatedly used on other values of the parameter(s), to obtain a number of additional second values of the attribute. Applying to the additional second values, a function obtained by calibrating the at least one second value to the at least one first value, can yield calibrated estimates very quickly, which represent the attribute's variation relatively accurately.
    Type: Grant
    Filed: September 3, 2013
    Date of Patent: December 30, 2014
    Assignee: Synopsys, Inc.
    Inventors: Nahmsuk Oh, Peivand Fallah-Tehrani, Alireza Kasnavi, Subramanyam Sripada
  • Publication number: 20140059508
    Abstract: A computer-implemented method of determining an attribute of a circuit includes using a computationally expensive technique to simulate the attribute (such as timing delay or slew) of a portion of the circuit, at predetermined values of various parameters (e.g. nominal values of channel length or metal width), to obtain at least a first value of the attribute. The method also uses a computationally inexpensive technique to estimate the same attribute, thereby to obtain at least a second value which is less accurate than the first value. Then the computationally inexpensive technique is repeatedly used on other values of the parameter(s), to obtain a number of additional second values of the attribute. Applying to the additional second values, a function obtained by calibrating the at least one second value to the at least one first value, can yield calibrated estimates very quickly, which represent the attribute's variation relatively accurately.
    Type: Application
    Filed: September 3, 2013
    Publication date: February 27, 2014
    Applicant: Synopsys, Inc.
    Inventors: Nahmsuk Oh, Peivand Fallah-Tehrani, Alireza Kasnavi, Subramanyam Sripada
  • Patent number: 8555235
    Abstract: A computer-implemented method of determining an attribute of a circuit includes using a computationally expensive technique to simulate the attribute (such as timing delay or slew) of a portion of the circuit, at predetermined values of various parameters (e.g. nominal values of channel length or metal width), to obtain at least a first value of the attribute. The method also uses a computationally inexpensive technique to estimate the same attribute, thereby to obtain at least a second value which is less accurate than the first value. Then the computationally inexpensive technique is repeatedly used on other values of the parameter(s), to obtain a number of additional second values of the attribute. Applying to the additional second values, a function obtained by calibrating the at least one second value to the at least one first value, can yield calibrated estimates very quickly, which represent the attribute's variation relatively accurately.
    Type: Grant
    Filed: January 17, 2011
    Date of Patent: October 8, 2013
    Assignee: Synopsys, Inc.
    Inventors: Nahmsuk Oh, Peivand Fallah-Tehrani, Alireza Kasnavl, Subramanyam Sripada
  • Patent number: 8478573
    Abstract: A model for a circuit cell used in timing and signal integrity analysis in an integrated circuit design is automatically generated. A behavioral model, such as a gate current model is used in which the current in the circuit cell is determined as a function of the input voltage and the output voltage of the circuit cell as well as the history of at least one of the current, voltage, and charge values of the circuit cell. For example, the current in the circuit cell may be a function of the history of the current, which may be calculated incrementally using recursive convolution at each time step when using the model.
    Type: Grant
    Filed: June 23, 2005
    Date of Patent: July 2, 2013
    Assignee: Synopsys, Inc.
    Inventors: Li Ding, Peivand Fallah-Tehrani, Alireza Kasnavi
  • Patent number: 7962876
    Abstract: Static timing and/or noise analysis are performed on a netlist of an integrated circuit, to estimate behavior of the netlist and to identify at least one violation by said behavior of a corresponding requirement thereon, such as setup time, hold time or bump height in a quiescent net. Thereafter, effect of engineering change order (ECO) to correct the violation are automatically analyzed, based on the layout, the parasitics, the timing and/or noise behavior, and the violation, followed by generation of a constraint on the behavior (called “ECO” constraint), such as a timing constraint and/or a noise constraint. Next, the ECO constraint is automatically used, e.g. in a place and route tool, to select an ECO repair technique, from several ECO repair techniques that can overcome the violation. The selected ECO repair technique is automatically applied to the layout, to generate a modified layout which does not have the violation.
    Type: Grant
    Filed: October 31, 2008
    Date of Patent: June 14, 2011
    Assignee: Synopsys, Inc.
    Inventors: Nahmsuk Oh, Peivand Fallah-Tehrani, Alireza Kasnavi
  • Publication number: 20110113396
    Abstract: A computer-implemented method of determining an attribute of a circuit includes using a computationally expensive technique to simulate the attribute (such as timing delay or slew) of a portion of the circuit, at predetermined values of various parameters (e.g. nominal values of channel length or metal width), to obtain at least a first value of the attribute. The method also uses a computationally inexpensive technique to estimate the same attribute, thereby to obtain at least a second value which is less accurate than the first value. Then the computationally inexpensive technique is repeatedly used on other values of the parameter(s), to obtain a number of additional second values of the attribute. Applying to the additional second values, a function obtained by calibrating the at least one second value to the at least one first value, can yield calibrated estimates very quickly, which represent the attribute's variation relatively accurately.
    Type: Application
    Filed: January 17, 2011
    Publication date: May 12, 2011
    Inventors: Nahmsuk Oh, Peivand Fallah-Tehrani, Alireza Kasnavi, Subramanyam Sripada
  • Patent number: 7900165
    Abstract: A computer-implemented method of determining an attribute of a circuit includes using a computationally expensive technique to simulate the attribute (such as timing delay or slew) of a portion of the circuit, at predetermined values of various parameters (e.g. nominal values of channel length or metal width), to obtain at least a first value of the attribute. The method also uses a computationally inexpensive technique to estimate the same attribute, thereby to obtain at least a second value which is less accurate than the first value. Then the computationally inexpensive technique is repeatedly used on other values of the parameter(s), to obtain a number of additional second values of the attribute. Applying to the additional second values, a function obtained by calibrating the at least one second value to the at least one first value, can yield calibrated estimates very quickly, which represent the attribute's variation relatively accurately.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: March 1, 2011
    Assignee: Synopsys, Inc.
    Inventors: Nahmsuk Oh, Peivand Fallah-Tehrani, Alireza Kasnavi, Subramanyam Sripada
  • Publication number: 20090055787
    Abstract: Static timing and/or noise analysis are performed on a netlist of an integrated circuit, to estimate behavior of the netlist and to identify at least one violation by said behavior of a corresponding requirement thereon, such as setup time, hold time or bump height in a quiescent net. Thereafter, effect of engineering change order (ECO) to correct the violation are automatically analyzed, based on the layout, the parasitics, the timing and/or noise behavior, and the violation, followed by generation of a constraint on the behavior (called “ECO” constraint), such as a timing constraint and/or a noise constraint. Next, the ECO constraint is automatically used, e.g. in a place and route tool, to select an ECO repair technique, from several ECO repair techniques that can overcome the violation. The selected ECO repair technique is automatically applied to the layout, to generate a modified layout which does not have the violation.
    Type: Application
    Filed: October 31, 2008
    Publication date: February 26, 2009
    Inventors: Nahmsuk Oh, Peivand Fallah-Tehrani, Alireza Kasnavi
  • Patent number: 7454731
    Abstract: Static timing and/or noise analysis are performed on a netlist of an integrated circuit, to estimate behavior of the netlist and to identify at least one violation by said behavior of a corresponding requirement thereon, such as setup time, hold time or bump height in a quiescent net. Thereafter, effect of engineering change order (ECO) to correct the violation are automatically analyzed, based on the layout, the parasitics, the timing and/or noise behavior, and the violation, followed by generation of a constraint on the behavior (called “ECO” constraint), such as a timing constraint and/or a noise constraint. Next, the ECO constraint is automatically used, e.g. in a place and route tool, to select an ECO repair technique, from several ECO repair techniques that can overcome the violation. The selected ECO repair technique is automatically applied to the layout, to generate a modified layout which does not have the violation.
    Type: Grant
    Filed: September 22, 2006
    Date of Patent: November 18, 2008
    Assignee: Synopsys, Inc.
    Inventors: Nahmsuk Oh, Peivand Fallah-Tehrani, Alireza Kasnavi
  • Publication number: 20080243414
    Abstract: A computer-implemented method of determining an attribute of a circuit includes using a computationally expensive technique to simulate the attribute (such as timing delay or slew) of a portion of the circuit, at predetermined values of various parameters (e.g. nominal values of channel length or metal width), to obtain at least a first value of the attribute. The method also uses a computationally inexpensive technique to estimate the same attribute, thereby to obtain at least a second value which is less accurate than the first value. Then the computationally inexpensive technique is repeatedly used on other values of the parameter(s), to obtain a number of additional second values of the attribute. Applying to the additional second values, a function obtained by calibrating the at least one second value to the at least one first value, can yield calibrated estimates very quickly, which represent the attribute's variation relatively accurately.
    Type: Application
    Filed: March 30, 2007
    Publication date: October 2, 2008
    Applicant: Synopsys, Inc.
    Inventors: Nahmsuk Oh, Peivand Fallah-Tehrani, Alireza Kasnavi, Subramanyam Sripada
  • Patent number: 7272807
    Abstract: An equivalent waveform for a distorted waveform used in timing and signal integrity analysis in the design of an integrated circuit is automatically generated. The equivalent waveform is produced by calculating the transition quantity of a first non-distorted waveform. The transition quantity is the amount of transition of the first non-distorted waveform that is required for the cell to produce an output waveform with a predetermined end voltage. The end point of the transition period for the distorted waveform is then determined based on when the distorted waveform has accumulated the same transition quantity. The equivalent waveform can then be formed by computing a second non-distorted waveform such that the end point of the transition period for the second non-distorted waveform coincides with the end point of the transition period for the distorted waveform.
    Type: Grant
    Filed: March 2, 2005
    Date of Patent: September 18, 2007
    Assignee: Synopsys, Inc.
    Inventors: Li Ding, Peivand Fallah Tehrani, Alireza Kasnavi
  • Patent number: 7263676
    Abstract: One embodiment of the invention provides a system that analyzes the propagation of noise through an integrated circuit. During operation, the system obtains an input noise signal to be applied to a cell within the integrated circuit. The system then looks up parameters specifying how noise affects the cell, and then uses the parameters to determine how the input noise signal affects the cell. This can involve determining if the input noise signal will cause the cell to fail and/or determining a propagated noise signal that emanates from the cell.
    Type: Grant
    Filed: April 9, 2003
    Date of Patent: August 28, 2007
    Assignee: Synopsys, Inc.
    Inventors: Alexander Gyure, Jindrich Zejda, Peivand Fallah-Tehrani, Wenyuan Wang, Chi-Chong Lo, Seyed Alireza Kasnavi, Mahmoud Shahram, Yansheng Luo, William Chiu-Ting Shu
  • Publication number: 20070010981
    Abstract: A model for a circuit cell used in timing and signal integrity analysis in an integrated circuit design is automatically generated. A behavioral model, such as a gate current model is used in which the current in the circuit cell is determined as a function of the input voltage and the output voltage of the circuit cell as well as the history of at least one of the current, voltage, and charge values of the circuit cell. For example, the current in the circuit cell may be a function of the history of the current, which may be calculated incrementally using recursive convolution at each time step when using the model.
    Type: Application
    Filed: June 23, 2005
    Publication date: January 11, 2007
    Applicant: Synopsys, Inc.
    Inventors: Li Ding, Peivand Fallah-Tehrani, Alireza Kasnavi
  • Publication number: 20060200784
    Abstract: An equivalent waveform for a distorted waveform used in timing and signal integrity analysis in the design of an integrated circuit is automatically generated. The equivalent waveform is produced by calculating the transition quantity of a first non-distorted waveform. The transition quantity is the amount of transition of the first non-distorted waveform that is required for the cell to produce an output waveform with a predetermined end voltage. The end point of the transition period for the distorted waveform is then determined based on when the distorted waveform has accumulated the same transition quantity. The equivalent waveform can then be formed by computing a second non-distorted waveform such that the end point of the transition period for the second non-distorted waveform coincides with the end point of the transition period for the distorted waveform.
    Type: Application
    Filed: March 2, 2005
    Publication date: September 7, 2006
    Applicant: Synopsys, Inc.
    Inventors: Li Ding, Peivand Fallah-Tehrani, Alireza Kasnavi
  • Patent number: 7007252
    Abstract: One embodiment of the invention provides a system that characterizes cells within an integrated circuit. During operation, the system obtains a number of input noise signals to be applied to the cell. The system then simulates responses of the cell to each of the input noise signals, and stores a representation of the responses. This allows a subsequent analysis operation to access the stored representation to determine a response of the cell instead of having to perform a time-consuming simulation operation.
    Type: Grant
    Filed: April 9, 2003
    Date of Patent: February 28, 2006
    Assignee: Synopsys, Inc.
    Inventors: Alexander Gyure, Jindrich Zejda, Peivand Fallah-Tehrani, Wenyuan Wang, Chi-Chong Lo, Mahmoud Shahram, Yansheng Luo, William Chiu-Ting Shu, Seyed Alireza Kasnavi
  • Publication number: 20040205682
    Abstract: One embodiment of the invention provides a system that analyzes the propagation of noise through an integrated circuit. During operation, the system obtains an input noise signal to be applied to a cell within the integrated circuit. The system then looks up parameters specifying how noise affects the cell, and then uses the parameters to determine how the input noise signal affects the cell. This can involve determining if the input noise signal will cause the cell to fail and/or determining a propagated noise signal that emanates from the cell.
    Type: Application
    Filed: April 9, 2003
    Publication date: October 14, 2004
    Inventors: Alexander Gyure, Jindrich Zejda, Peivand Fallah-Tehrani, Wenyuan Wang, Chi-Chong Lo, Seyed Alireza Kasnavi, Mahmoud Shahram, Yansheng Luo, William Chiu-Ting Shu
  • Publication number: 20040205680
    Abstract: One embodiment of the invention provides a system that characterizes cells within an integrated circuit. During operation, the system obtains a number of input noise signals to be applied to the cell. The system then simulates responses of the cell to each of the input noise signals, and stores a representation of the responses. This allows a subsequent analysis operation to access the stored representation to determine a response of the cell instead of having to perform a time-consuming simulation operation.
    Type: Application
    Filed: April 9, 2003
    Publication date: October 14, 2004
    Applicant: Entire Interest
    Inventors: Alexander Gyure, Jindrich Zejda, Peivand Fallah-Tehrani, Wenyuan Wang, Chi-Chong Lo, Mahmoud Shahram, Yansheng Luo, William Chiu-Ting Shu, SEYED ALIREZA KASNAVI
  • Patent number: 6405348
    Abstract: A method for static timing analysis of deep sub-micron devices in presence of crosstalk. The present invention provides an efficient platform for fast and accurate static timing verification of large scale transistor and cell level netlists, with coupled interconnects and high switching speeds. The present invention also provides a novel approach to solve the coupled noise problem in static timing verification. The present invention also provides for a method of determining worst case aggressor switching time for a cross-coupled interconnect stage. After the worst case aggressor switching time is determined, the netlist is then resimulated using the worst case aggressor switching time to determine more accuate stage delay and slew of the interconnect stage. The output waveform is recorded and utilized as the input of subsequent stages.
    Type: Grant
    Filed: January 11, 2000
    Date of Patent: June 11, 2002
    Assignee: Synopsys, Inc.
    Inventors: Peivand Fallah-Tehrani, Shang-Woo Chyou