Patents Assigned to Cadence Design Systems
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Publication number: 20040133369Abstract: A method for inspecting lithography masks includes generating integrated circuit design data and using context information from the integrated circuit design data to inspect a mask.Type: ApplicationFiled: July 14, 2003Publication date: July 8, 2004Applicant: Cadence Design Systems, Inc.Inventors: Robert C. Pack, Louis K. Scheffer
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Patent number: 6760894Abstract: A method and mechanism for performing a timing analysis on virtual component blocks, which is an abstraction of a circuit block is provided. A set of modes for a circuit block are identified, where a mode is a set of meaningful control input values. Each functionally meaningful or useful control input combination is applied to the circuit block. For each control input combination applied, a delay for each data input/output path and each control input/output path not passing through a blocked circuit node for the applied combination of control inputs is calculated. The delay information for the data paths and control paths is stored within a timing model. The delay information may include a maximum or minimum delay for the circuit block. The timing of sequential circuit blocks may also characterized using the methods and mechanisms herein.Type: GrantFiled: June 14, 2002Date of Patent: July 6, 2004Assignee: Cadence Design Systems, Inc.Inventors: Hakan Yalcin, Cyrus S. Bamji, Mohammad S. Mortazavi, Robert J. Palermo
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Publication number: 20040128406Abstract: A method for improving the efficiency of test sequences for circuits with embedded multiple-port arrays, such as random access memory (RAM), is described, With existing test generation methods, it is a common occurrence that a resulting test sequence only utilizes a minimum number of read ports for detecting a target fault. When this type of test sequences is applied, one or more outputs of embedded RAMs may not attain known values, consequently reducing the effectiveness of the test sequences. The present invention enhances test sequences to that when they are applied, all outputs of embedded RAMs attain known values.Type: ApplicationFiled: September 3, 2003Publication date: July 1, 2004Applicant: Cadence Design Systems, Inc.Inventors: Xinghao Chen, Joseph C. Watkins
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Patent number: 6751786Abstract: A method is disclosed for synthesizing a clock tree for a partitioned integrated circuit (IC) layout comprising a plurality of base level partitions and a top level partition each occupying a separate area of a semiconductor substrate. The base level partitions include syncs to be clocked by edges of a clock signal applied to an entry node within the area occupied by the top level partition. In accordance with the method, a plurality of independently balanced subtrees are separately synthesized. Each subtree resides within the area occupied by a separate base level partition and includes a start point at a perimeter of the area occupied by that base level partition and a network of buffers and signal paths for conveying a clock signal edge from the start point to each sync included within that area. Thereafter a top level portion of the clock tree is synthesized.Type: GrantFiled: January 9, 2002Date of Patent: June 15, 2004Assignee: Cadence Design Systems, Inc.Inventors: Chin-Chi Teng, Wei-Jin Dai
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Publication number: 20040107412Abstract: A method for generating lithography marks includes generating integrated circuit design data and using context information from the integrated circuit design data to write a mask.Type: ApplicationFiled: July 14, 2003Publication date: June 3, 2004Applicant: Cadence Design Systems, Inc.Inventors: Robert C. Pack, Louis K. Scheffer
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Patent number: 6745379Abstract: Some embodiments provide a hierarchical method of routing nets within a particular region of a circuit layout. Each net has a set of pins. The method initially partitions the particular region into a first set of sub-regions. For each net, the method identifies a first route that connects a group of first-set sub-regions containing the first net's pins; where some of the routes have at least one route-edge that is at least partially diagonal. The method then partitions the sub-regions into a second set of smaller sub-regions. For a first net, the method identifies a propagation of the first-net's first route into the second-set sub-regions based on congestion between the second-set sub-regions. It then adjusts the congestion between the second set sub-regions based on the identified propagation. For a second net, the method then identifies a propagation of the second-net's first route into the second-set sub-regions based on congestion between the second-set sub-regions.Type: GrantFiled: January 13, 2002Date of Patent: June 1, 2004Assignee: Cadence Design Systems, Inc.Inventors: Steven Teig, Oscar Buset
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Patent number: 6742174Abstract: A method for modeling a circuit design includes synthesizing the circuit design to create a first gate-level representation of the circuit design. The method also includes analyzing a second gate-level representation of the circuit design to learn architecture information, and resynthesizing the first gate-level representation of the circuit design to incorporate the learned architecture information from the second gate-level representation of the circuit design. A computer-readable storage medium has stored thereon computer instructions that, when executed by a computer, cause the computer to synthesize a circuit design to create a first gate-level representation of the circuit design.Type: GrantFiled: October 19, 2001Date of Patent: May 25, 2004Assignee: Cadence Design Systems, Inc.Inventors: Kuang-Chien Chen, Chih-Chang Lin, Cheng-Ta Hsieh, Yifeng Wang
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Publication number: 20040098688Abstract: Disclosed is a method, system, and article of manufacture for a one-pass approach for implementing metal-fill for an integrated circuit. Also disclosed is a method, system, and article of manufacture for implementing metal-fill that is coupled to a tie-off connection. An approach that is disclosed comprises a method, system, and article of manufacture for implementing metal-fill having an elongated shape that corresponds to the length of whitespace. Also disclosed is the aspect of implementing metal-fill that matches the routing direction. Yet another disclosure is an implementation of a place & route tool incorporating an integrated metal-fill mechanism.Type: ApplicationFiled: November 19, 2002Publication date: May 20, 2004Applicant: Cadence Design Systems, Inc.Inventors: Thanh Vuong, William H. Kao, David C. Noice
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Publication number: 20040098674Abstract: Disclosed is a method, system, and article of manufacture for a one-pass approach for implementing metal-fill for an integrated circuit. Also disclosed is a method, system, and article of manufacture for implementing metal-fill that is coupled to a tie-off connection. An approach that is disclosed comprises a method, system, and article of manufacture for implementing metal-fill having an elongated shape that corresponds to the length of whitespace. Also disclosed is the aspect of implementing metal-fill that matches the routing direction. Yet another disclosure is an implementation of a place & route tool incorporating an integrated metal-fill mechanism.Type: ApplicationFiled: November 19, 2002Publication date: May 20, 2004Applicant: Cadence Design Systems, Inc.Inventors: Thanh Vuong, William H. Kao, David C. Noice
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Publication number: 20040098393Abstract: Disclosed is a method, system, and article of manufacture for a one-pass approach for implementing metal-fill for an integrated circuit. Also disclosed is a method, system, and article of manufacture for implementing metal-fill that is coupled to a tie-off connection. An approach that is disclosed comprises a method, system, and article of manufacture for implementing metal-fill having an elongated shape that corresponds to the length of whitespace. Also disclosed is the aspect of implementing metal-fill that matches the routing direction. Yet another disclosure is an implementation of a place & route tool incorporating an integrated metal-fill mechanism.Type: ApplicationFiled: November 19, 2002Publication date: May 20, 2004Applicant: Cadence Design Systems, Inc.Inventors: Thanh Vuong, William H. Kao, David C. Noice
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Patent number: 6738960Abstract: Some embodiments provide a method of producing sub-optimal routes for a net having a set of pins in a region of an integrated-circuit (“IC”) layout. In some embodiments, such a method is used for a router that partitions the region into a plurality of sub-regions. This method initially identifies a first set of sub-regions that contain the net's pins. It then obtains a second set of sub-regions by adding a third set of sub-regions to the first set of sub-regions. Each sub-region in the third set does not contain any pins of the net. For the second set of sub-regions, the method then identifies a first set of routes, where each route traverses the sub-regions in the second set.Type: GrantFiled: January 5, 2002Date of Patent: May 18, 2004Assignee: Cadence Design Systems, Inc.Inventors: Steven Teig, Oscar Buset, Yang-Trung Lin
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Patent number: 6735748Abstract: A machine-learning model may be created to perform integrated circuit layout extraction. Using such a machine-learning system has two main phases: model creation and model application. The model creation phase comprises creating one or more extraction models using machine-learning techniques. The machine learning is performed by first creating training data sets composed of the identified parameters from typical examples of the smaller extraction problem and the answers to those example extraction problems as solved using a highly accurate physics-based field solver. Next, the system performs machine learning using Bayesian inference in order to train the neural network models. The Bayesian inference may be implemented with normal Monte Carlo techniques, Hybrid Monte Carlo techniques, or other Bayesian learning techniques. After the creation of a set of models for each of the smaller simpler extraction problems, the machine-learning based models may be used for extraction.Type: GrantFiled: January 31, 2002Date of Patent: May 11, 2004Assignee: Cadence Design Systems, Inc.Inventors: Steven Teig, Arindam Chatterjee
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Patent number: 6731141Abstract: A line driver provides an output signal onto an output. The line driver includes a first current driver coupled to a first terminal of the output. The first current driver is capable of providing a first current to the first terminal that is sufficient to cause an output voltage having a magnitude Y to appear across the output. The first current driver includes a first plurality of elements to provide the first current to the first terminal of the output, each of the plurality of elements having a maximum voltage tolerance that is less than the magnitude Y.Type: GrantFiled: August 7, 2001Date of Patent: May 4, 2004Assignee: Cadence Design Systems, Inc.Inventors: Mark Summers, John Mullen
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Patent number: 6728945Abstract: A method and system are provided for computing behavioral level observabilities of a digital system. In one example, a logic network is provided for performing an observability analysis at the behavioral level of a digital system. The logic network includes logic objects configured to emulate behavioral observabilities computed from a control data flow graph (CDFG), wherein the logic objects include at least one of: first logic objects configured to compute a token observable condition (TOC) of an edge of the CDFG; and second logic objects configured to compute a node observable condition (NOC) of a node of the CDFG. A logic optimization is used to optimize the logic network to obtain an optimized logic network of the behavioral observabilities.Type: GrantFiled: February 26, 2001Date of Patent: April 27, 2004Assignee: Cadence Design Systems, Inc.Inventor: Qi Wang
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Patent number: 6728914Abstract: For each logic gate in a logic circuit, all paths containing the gate are determined and the paths are classified by their length between each of the input or launch SRLs and each output or capture SRL. The paths are assigned a single threshold value and then divided into two groups in accordance with their path length classification relative to the threshold value with all paths in each group treated as a single path. Pseudo random LBIST patterns are then simulated using standard LBIST tool. When a fault associated with a logic gate is detected by a capture SRL of a path with a length above the threshold, the fault is viewed as tested and marked off from the fault list. When a fault is detected in any path that is below the threshold, it is not marked off and testing of the fault continues until testing patterns for all the paths of the group falling below the threshold value are simulated.Type: GrantFiled: December 22, 2000Date of Patent: April 27, 2004Assignee: Cadence Design Systems, IncInventors: Kevin William McCauley, William Vincent Huott, Mary Prilotski Kusko, Peilin Song, Richard Frank Rizzolo, Ulrich Baur, Franco Motika
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Patent number: 6725432Abstract: A method and apparatus for designing a circuit system, including selecting a plurality of pre-designed circuit blocks to be used to design the circuit system, collecting data reflecting the experience of the designer regarding the pre-designed circuit blocks, the designer's experience being adaptable to a processing method, accepting or rejecting a design of the circuit system in a manner based on the designer's experience data and acceptable degree of risk, upon acceptance, forming block specifications containing criteria and modified constraints for each of the circuit blocks, upon acceptance, forming block specifications for deploying the circuit blocks on a floor plan of a chip, as a system on a chip, in compliance with the criteria and modified constraints, and substantially without changing the selected circuit block and the processing method.Type: GrantFiled: March 23, 2001Date of Patent: April 20, 2004Assignee: Cadence Design Systems, Inc.Inventors: Henry Chang, Larry Cooke, Merrill Hunt, Wuudiann Ke, Christopher K. Lennard, Grant Martin, Peter Paterson, Khoan Truong, Kumar Venkatramani
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Patent number: 6725187Abstract: A system and method are provided for selectively inferring latch elements in a circuit design from an event-driven hardware description language (HDL) file to an event-independent format. The method includes modeling the file as a plurality of data flow equations, analyzing the plurality of equations for uninitialized variables, and placing a latch at any utilized, uninitialized variable. Control signal information for an inferred latch is also derived during the data flow analysis.Type: GrantFiled: June 12, 2000Date of Patent: April 20, 2004Assignee: Cadence Design Systems, Inc.Inventors: Szu-Tsung Cheng, Alexander Saldanha, Patrick C. McGeer, Patrick Scaglia
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Patent number: 6725185Abstract: Methods and apparatus for modeling noise present in an integrated circuit substrate are disclosed. A position on a surface of the integrated circuit substrate is obtained. A combination of layers associated with the position and defining a vertical column beneath the position is ascertained. A doping profile associated with the combination of layers is obtained. The doping profile includes a plurality of portions, each of which is associated with a different range of substrate depth. Noise in the integrated circuit substrate is then modeled using the obtained doping profile.Type: GrantFiled: July 11, 2001Date of Patent: April 20, 2004Assignee: Cadence Design Systems, Inc.Inventor: Francois J. R. Clèment
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Patent number: 6721922Abstract: A system is herein disclosed which allows for the interactive design and analysis of analog and mixed-signal circuits. Circuits may additionally be characterized and verified without leaving the environment provided by the system. The system may be used to analyze multiple circuit designs at the same time. In this manner a designer can create a test that sweeps over several circuit designs. Embodiments of the invention may be integrated with other circuit design tools and development systems.Type: GrantFiled: September 27, 2001Date of Patent: April 13, 2004Assignee: Cadence Design Systems, Inc.Inventors: Don Walters, Paul Foster, Tina Najibi
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Patent number: 6721929Abstract: A variable current source model accurately determines timing delays for designs of circuits implemented in integrated circuits. A design for an integrated circuit specifies a resistive-capacitive (“RC”) network. The RC network couples a driving point and a receiving point, and a circuit specified in the design, drives the RC network at the driving point. The variable current source model determines driving currents for the circuit at the driving point based on the RC network and a characterization model of the circuit. A timing delay between the driving point and the receiving point is determined by simulating the drive of the RC network with the driving current at the driving point.Type: GrantFiled: May 11, 2001Date of Patent: April 13, 2004Assignee: Cadence Design Systems, Inc.Inventors: Jun Li, Hong Zhao, Hsien-Yen Chiu