Circuit Simulation Patents (Class 703/14)
  • Patent number: 7003745
    Abstract: Each circuit simulation performed on unique layout of circuit devices generates a design point (DP) that includes device variable values and performance goal values. Circuit models for at least one performance goal are determined as a function of a first subset of the DPs. A performance goal value is determined for each circuit model based on the device variable values obtained from a second subset of the DPs. Errors are determined between the thus determined value of each performance goal and values of the corresponding performance goals obtained from the second subset of the DPs. Input values of device variables are processed with at least one of the circuit models having the smallest error associated therewith to determine therefor a performance goal value. A layout of the circuit devices is generated based on the input device variable values associated with at least one of the thus determined performance goals.
    Type: Grant
    Filed: August 11, 2003
    Date of Patent: February 21, 2006
    Assignee: Cadence Design Systems, Inc.
    Inventors: Pero Subasic, Rodney Phelps
  • Patent number: 6999910
    Abstract: The present invention is directed to a comprehensive design flow system. A system and method are provided that provide a comprehensive system to introduce a metamethodology that integrates EDA design tools into a manageable and predictable design flow. A method of designing an integrated circuit may include accessing a design utility operating on an information handling system, displaying a dynamic template on a display device of an information handling system, wherein the dynamic template implements at least two symbols displayable on a display device, in which the at least two symbols each correspond to a respective EDA tool, and arranging the at least two symbols displayed on the display device. The at least two symbols are arranged to indicate an interrelationship of the EDA tools in a design process of an integrated circuit.
    Type: Grant
    Filed: November 20, 2001
    Date of Patent: February 14, 2006
    Assignee: LSI Logic Corporation
    Inventors: James S. Koford, Christopher L. Hamlin
  • Patent number: 6999911
    Abstract: In a method and apparatus for carrying out circuit simulation which performs circuit simulation on a circuit to be simulated, a plurality of partial circuits to be inspected for equivalence in order to check if they exhibit equivalent operational characteristics are extracted from the circuit to be simulated, and the intensity of the influence of an external terminal of the circuit to be simulated is assessed by tracing paths linking the external terminal and given terminals of the partial circuits. Moreover, based on the configurations of the partial circuits, the connectional relationships of corresponding input terminals of the partial circuits, the operational characteristics of corresponding component elements of the partial circuits, and the intensity of the influence of the external terminal, the plurality of partial circuits are inspected for equivalence in order to detect partial circuits exhibiting equivalence.
    Type: Grant
    Filed: March 20, 1998
    Date of Patent: February 14, 2006
    Assignee: Fujitsu Limited
    Inventor: Hisanori Fujisawa
  • Patent number: 7000203
    Abstract: Disclosed is an improved method of determining mutual inductance of wires in an electronic design. First, the invention selects a pair of wires. Then, the invention adds concentric ring lines to the design. The invention then adds straight line segments representing each wire between points where each corresponding wire crosses the adjacent ring lines. Each of the straight lines run from a point where a corresponding wire crosses an outer concentric ring line to a point where the corresponding wire crosses an inner concentric ring line. The invention can then very simply calculate the mutual inductance between the straight line segments (not the actual potentially non-linear wires themselves). The mutual inductance of the straight line segments only comprises an approximate mutual inductance of the wires because the actual mutual inductance of the wires may be slightly different if the wires are non-linear.
    Type: Grant
    Filed: November 12, 2003
    Date of Patent: February 14, 2006
    Assignee: International Business Machines Corporation
    Inventors: Patrick H. Buffet, Charles S. Chiu, Gustina B. Collins, Craig P. Lussier
  • Patent number: 6996799
    Abstract: An integrated circuit is designed by interconnecting pre-designed data-driven cores (intellectual property, functional blocks). Hardware description language (e.g. Verilog or VHDL) and software language (e.g. C or C++) code for interconnecting the cores is automatically generated by software tools from a central circuit specification. The central specification recites pre-designed hardware cores (intellectual property) and the interconnections between the cores. HDL and software language test benches, and timing constraints are also automatically generated from the central specification. The automatic generation of code simplifies the interconnection of pre-existing cores for the design of complex integrated circuits.
    Type: Grant
    Filed: August 8, 2000
    Date of Patent: February 7, 2006
    Assignee: Mobilygen Corporation
    Inventors: Sorin C. Cismas, Kristan J. Monsen, Henry K. So
  • Patent number: 6996512
    Abstract: A method, system, and computer program product for allocating buffer and wire placement in an integrated circuit design is provided. In one embodiment, the surface of a integrated circuit design is represented as a tile graph. Allocation of buffer locations for selected tiles in the tile graph is then received and nets are routed between associated sources and sinks. Buffer locations within selected tiles are then selectively assigned based upon buffer needs of the nets, wherein the nets are routed through selected tiles and assigned buffer locations using a cost minimization algorithm.
    Type: Grant
    Filed: April 19, 2001
    Date of Patent: February 7, 2006
    Assignee: International Business Machines Corporation
    Inventors: Charles Jay Alpert, Jiang Hu, Paul Gerard Villarrubia
  • Patent number: 6996513
    Abstract: A method and system for identifying an inaccurate model of a hardware circuit includes the steps of simulating a digital model and an analogue model of the circuit to provide first and second sets of simulation results respectively. For each result in the first and second sets of simulation an integer value is determined which represents that result. The integer values are stored in first and second sets of comparison results respectively and the sets of comparison results are compared. An output signal indicating that at least one of the models is inaccurate is produced if the comparison results contradict.
    Type: Grant
    Filed: June 7, 2001
    Date of Patent: February 7, 2006
    Assignee: STMicroelectronics Limited
    Inventor: Peter Bellam
  • Patent number: 6993468
    Abstract: A transaction rule is used to recognize a set of simulation signals obtained from a design simulation as a transaction. An action associated with the transaction rule is executed to produce an output identifying the transaction.
    Type: Grant
    Filed: December 27, 2000
    Date of Patent: January 31, 2006
    Assignee: Intel Corporation
    Inventors: David J. Harriman, Arthur D. Hunter, Arvind B. Iyer
  • Patent number: 6993470
    Abstract: The invention presents a method for selecting test cases in a test simulation of logic designs to improve speed and effectiveness of such testing. The method for selecting such test cases after such test cases are generated includes generating a test-coverage file and a harvest-goals file for the test case. The harvest-goals file contains a list of events and initial goal for each event. Harvest criteria is used to determined whether the number of hits for each event meets the initial goal. By applying the harvest criteria to the test case, it is determined whether to harvest the test case. The test case is saved and identified for harvest, if the test case is determined to be harvested. Also, the harvest-goals file is adjusted, if the test case is determined to be harvested.
    Type: Grant
    Filed: June 26, 2001
    Date of Patent: January 31, 2006
    Assignee: International Business Machines Corporation
    Inventors: Yoanna Baumgartner, Maureen T. Davis, Joseph D. Gerwels, Kirk E. Morrow
  • Patent number: 6993467
    Abstract: An offline trim circuit includes one or more irreversible trim elements, such as fuses, for example, used for setting electrical parameters to desired values. Associated circuitry is employed to verify the effect of trimming, prior to permanently setting trim bit values, permitting the optimal definition of the trim bit sequence and completely eliminating guesswork from the trimming procedure.
    Type: Grant
    Filed: December 5, 2000
    Date of Patent: January 31, 2006
    Assignee: Toko, Inc.
    Inventors: Gabe C. Gavrila, Troy J. Littlefield, Fernando Ramon Martin-Lopez
  • Patent number: 6993469
    Abstract: A significant improvement over current methods for co-simulation of the hardware and software components of embedded digital system designs is provided. The present invention integrates the hardware and software components of a system design into a single unified simulation environment. The unified simulation environment and the various component models of the system design are created in a high level general purpose programming language. This allows inter-component communications and communications with the unified simulation environment to be carried out through the use of function calls, which significantly increases the overall simulation speed. Additionally, the unified simulation environment runs as a single process, which significantly improves debugging capabilities.
    Type: Grant
    Filed: June 2, 2000
    Date of Patent: January 31, 2006
    Assignee: ARM Limited
    Inventor: Ulrich Bortfeld
  • Patent number: 6990438
    Abstract: A technique for observability based coverage of a design under test (DUT) is presented. A conventional simulation signal is augmented to include a “tag value.” In the course of a simulation, assignment statements (for which observability-based coverage is desired) “inject” tag values on their output signals. A tag value contains an identifier uniquely identifying the assignment statement that produced it. A tag value also contains a “tag history.” The tag history contains copies of the tag values for assignment statements earlier in the flow of control or in the flow of data. If a tag propagated through the DUT appears at an observable output, the circuit designer knows that the assignment statements it identifies have satisfied observability based coverage.
    Type: Grant
    Filed: September 12, 2000
    Date of Patent: January 24, 2006
    Assignee: Synopsys, Inc.
    Inventors: Debashis Roy Chowdhury, Pallab Kumar Dasgupta, Surrendra Amul Dudani, Ghassan Khoory
  • Patent number: 6985843
    Abstract: The invention relates to a method for modeling an input/output cell located on the perimeter of an integrated circuit. A method is taught to model an the integrated circuit when sufficient area is not available on the perimeter of the integrated circuit. The input/output cell can be modeled in two locations; one location on the perimeter of the cell and a second location in the interior area, or core, of the integrated circuit. The model uses a cover to prevent the area of the core of the integrated circuit from being used for other purposes. When the input/output cell is divided into a main cell and more than one pre-cell, the model uses a cover for each pre-cell. The model adjusts the timing of the signals to compensate for the input/output cell being divided into two areas. In an embodiment a software tool performs the functions of the model.
    Type: Grant
    Filed: June 11, 2001
    Date of Patent: January 10, 2006
    Assignee: NEC Electronics America, Inc.
    Inventor: Attila Kovacs-Birkas
  • Patent number: 6985842
    Abstract: A system and method is provided to accurately model bidirectional wire I/O using hardware description language (HDL). The preferred model and method uses an HDL model that provides two parallel paths between ports of the bidirectional wire I/O. During simulation, the ports are monitored for activity. When an event is detected on either port, the model checks both ports to see if they are different values. If the ports are different values, one of the two parallel paths is enabled and the other disabled. For example, the model enables the path in which the new signal has appeared and thus passes the signal to the other port. The preferred model allows for the use of HDL elements that support full timing annotation. The preferred embodiment also removes the possibility of high impedance transition error that can result from false transitions to a high impedance state.
    Type: Grant
    Filed: May 11, 2001
    Date of Patent: January 10, 2006
    Assignee: International Business Machines Corporation
    Inventors: Richard J. Grupp, Yelena M. Tsyrkina
  • Patent number: 6985840
    Abstract: Described herein is a system for verifying that a circuit described by a hardware description language file has a property of responding to an antecedent event represented by a particular pattern in its input signals by exhibiting a consequent behavior of producing a particular pattern in its output signals during a finite time following the antecedent event. The system includes a conventional circuit simulator for simulating the behavior of the circuit under conditions defined by a user-provided test bench. The simulator produces output waveform data representing the behavior of the circuit input, output and internal signals, including signals representing the circuit's state. When the output waveform data indicates the antecedent event has occurred, the system determines the current state of the circuit from the waveform data.
    Type: Grant
    Filed: July 31, 2000
    Date of Patent: January 10, 2006
    Assignee: Novas Software, Inc.
    Inventors: Yu-Chin Hsu, Furshing Tsai, Tayung Liu
  • Patent number: 6985847
    Abstract: A computer-implemented method for matching parameters of outputs generated by a first and second process. The first process generates a first output having a characteristic measurable by a first parameter, and the second process generates a second output having the characteristic measurable by a second parameter. A computer having a processing unit and memory is provided. The computer generates a first model of the first parameter for the first process and a second model of the second parameter for the second process. The computer generates a first simulated output of the first process using the first model. A correction, which is a function of the second model and which compensates for the effect of the second process on the second parameter, is applied to the first simulated output to obtain a corrected output. The second process is applied to the corrected output to generate with the computer thereby a third output matching the first parameter of the first output.
    Type: Grant
    Filed: August 29, 2002
    Date of Patent: January 10, 2006
    Assignee: Micron Technology, Inc.
    Inventors: James Burdorf, Christophe Pierrat
  • Patent number: 6983234
    Abstract: A method and system for accurately validating performance and functionality of a processor in a timely manner is provided. First, a program is executed on a high level simulator of the processor. Next, a plurality of checkpoints are established. Then, state data at each of the checkpoints is saved. Finally, the program is run on a plurality of low level simulators of the processor in parallel, where each of the low level simulators is started at a corresponding checkpoint with corresponding state data associated with the corresponding checkpoint.
    Type: Grant
    Filed: March 20, 2000
    Date of Patent: January 3, 2006
    Assignee: Sun Microsystems, Inc.
    Inventors: Sudheendra Hangal, James M. O'Connor
  • Patent number: 6983432
    Abstract: A behavioral modeling technique that captures driver delay. The output characteristics of a typical driver are represented by two basic element types: switching and non-switching. Switching elements are functions of both time-varying and non-time-varying parameters, and non-switching elements are functions of non-time-varying parameters only. The outputs of these elements are characterized and tabulated by applying a DC voltage on the output of the driver and measuring the current through each element. The time-varying switching element are represent by time-controlled resistors. The invention provides a methodology to account for variations in input transition rate, supply voltage(s) or temperature.
    Type: Grant
    Filed: January 16, 2002
    Date of Patent: January 3, 2006
    Assignee: International Business Machines Corporation
    Inventor: Jerry D. Hayes
  • Patent number: 6983427
    Abstract: A technique to generate a logic design for use in designing an integrated circuit (IC). The technique includes embedding a combinatorial one-dimensional logic block within a two-dimensional schematic presentation to form a unified database. The technique also includes following a set of design capture rules, importing the combinatorial one-dimensional logic block, and notifying a designer when importing the combinatorial data block violates the set of design capture rules.
    Type: Grant
    Filed: August 29, 2001
    Date of Patent: January 3, 2006
    Assignee: Intel Corporation
    Inventors: William R. Wheeler, Matthew J. Adiletta
  • Patent number: 6981230
    Abstract: An efficient inductance modeling approach for on-chip power-ground wires using their effective self-loop-inductances is disclosed. Instead of extracting the inductive coupling between every two parallel wires and putting this huge number inductance elements into circuit simulation, this technique determines the effective self-loop-inductance for each power or ground wire segment and only generates a circuit with these effective self-inductors for simulation. This approach greatly reduces the circuit size and makes the full-chip power-ground simulation with the consideration of inductance feasible.
    Type: Grant
    Filed: July 30, 2002
    Date of Patent: December 27, 2005
    Assignee: Apache Design Solutions, Inc.
    Inventors: Shen Lin, Norman Chang, Weize Xie, Richard Chou
  • Patent number: 6980942
    Abstract: Plural boundary points are generated on a string on the surface of a material and a first length of a line segment between the boundary points is obtained. Then, the displacement of the boundary point according to a process model and the boundary point is moved by the displacement. A second length of the line segment between the boundary points after the boundary point is moved is found. When the second length is greater than a value obtained by multiplying the first length by a first factor exceeding 1, a new boundary point is added to the line segment whereas when the second length is smaller than a value obtained by multiplying the first length by a second factor less than 1, one of the boundary points of the line segment is eliminated.
    Type: Grant
    Filed: March 20, 2001
    Date of Patent: December 27, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Naoki Kusunoki, Nobutoshi Aoki, Hirotaka Amakawa
  • Patent number: 6980941
    Abstract: A system design support system is disclosed, which handles specifications at system level, e.g., a specification of software executed by a computer, specification of hardware implemented by combining semiconductor devices and the like, a specification of an incorporated system implemented by combining software and hardware, and a specification of a business process such as a workflow. This apparatus searches for an advertisement in accordance with an query specification. The apparatus also creates a communication procedure between the query specification and a specification of an advertisement part obtained by a search.
    Type: Grant
    Filed: January 31, 2002
    Date of Patent: December 27, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Mikito Iwamasa
  • Patent number: 6981238
    Abstract: In one embodiment, a schematic for a net includes a load and a load schematic. The load schematic may include a parasitic on the net, and an equivalent of the load. A buffer may be employed to couple the load schematic to the schematic. Among other advantages, this simplifies comparison of parasitics between the schematic and a corresponding layout.
    Type: Grant
    Filed: October 22, 2002
    Date of Patent: December 27, 2005
    Assignee: Cypress Semiconductor Corporation
    Inventor: Jonathan F. Churchill
  • Patent number: 6980943
    Abstract: A method and system for generating a synchronous sequence of vectors from information originating within an asynchronous environment is disclosed. A simulated asynchronous sequence is synchronized by extracting a state at each clock period to generate a simulation synchronous sequence. This sequence is manipulated first to include short delays for generating an asynchronous short-delay sequence and second to include long delays for generating an asynchronous long-delay sequence. An overlay is separately performed among the clock periods of the asynchronous short-delay sequence and the asynchronous long-delay sequence to respectively identify a first interval and a second interval. The first interval and the second interval are independently duplicated in successive clock periods to respectively generate a synchronous short-delay sequence and a synchronous long-delay sequence.
    Type: Grant
    Filed: December 13, 2001
    Date of Patent: December 27, 2005
    Assignee: Agilent Technologies, Inc.
    Inventors: Robert C. Aitken, Stuart L. Whannel, Jian-Jin Tuan
  • Patent number: 6981236
    Abstract: A method for modeling a device and a network to be analyzed in a complex simulation. The modeling method includes a device extraction step for extracting the structure of each of a plurality of devices included in the network to create device models showing the individual extracted structures, a device connection step for connecting the respective device models through the intermediary of an insulating portion for cutting off the electrical connection between the respective device models, and a circuit connection step for connecting a network model showing the network portion, from which the plurality of devices extracted in the device extraction step have been excluded, to a predetermined device model among the connected device models.
    Type: Grant
    Filed: September 24, 2003
    Date of Patent: December 27, 2005
    Assignee: Oki Electric Industry Co., Ltd.
    Inventor: Hirokazu Hayashi
  • Patent number: 6978231
    Abstract: A method and program product for instrumenting a hardware description language (HDL) design entity. The design entity is created utilizing a HDL source code file within the syntax convention of a platform HDL. In accordance with the method of the present invention an instrumentation entity is described within the HDL source code file utilizing a non-conventional syntax comment such that the instrumentation entity is embedded within the design entity without being incorporated into an overall design in which the design entity is incorporated. In accordance with a second embodiment, the HDL source code file includes a description of at least one operating event within the conventional syntax of the platform HDL, and the method of the present invention further includes associating the instrumentation entity with the operating event utilizing a non-conventional syntax comment within the HDL source code file.
    Type: Grant
    Filed: December 5, 2000
    Date of Patent: December 20, 2005
    Inventors: Derek Edward Williams, Bryan Ronald Hunt, Wolfgang Roesner
  • Patent number: 6978216
    Abstract: One or more methods and systems of validating the operation of one or more register designs are presented. In one embodiment, the system utilizes a processor, an integrated circuit design simulator software, a storage media, a storage device, user interface, and a display. In one embodiment, the method includes executing a set of instructions operating on a register design parameter file to produce an output that is easily incorporated into the integrated circuit design simulator software. The output specifies one or more tests to be performed using the integrated circuit design simulator software. The one or more tests are subsequently performed to validate the register design. The method automates the incorporation of register design parameters into the integrated circuit design simulator software by way of executing a set of instructions that operates on the register design parameter file.
    Type: Grant
    Filed: November 7, 2003
    Date of Patent: December 20, 2005
    Assignee: Broadcom Corporation
    Inventor: James D. Sweet
  • Patent number: 6975972
    Abstract: In simulating a physical circuit or system including analog and mixed signal digital-analog components, a computer models the physical circuit or system as a system of simultaneous equations. Conditional equations with associated conditions that can be true or false at different analog solution iterations result in a system of simultaneous equations that can change during the simulation. Rather than reformulating the system of simultaneous equations at each analog solution iteration, the system of simultaneous equations includes slots that are associated with conditional equations as the conditional equations become active. At a given point during the simulation, the conditions associated with the conditional equations are evaluated to determine which conditional equations are active. The values of the active conditional equations are placed in the slots in the system of simultaneous equations. System variables are associated with active conditional equations.
    Type: Grant
    Filed: June 8, 2000
    Date of Patent: December 13, 2005
    Assignee: Synopsys, Inc.
    Inventors: Gordon J. Vreugdenhil, Ernst Christen, Martin Vlach
  • Patent number: 6975977
    Abstract: A low-complexity, high accuracy model of a CPU anti-resonance system has been developed. The model includes a simulated load model, a simulated transistor that simulates the performance of a high frequency capacitor, and a simulated capacitor that simulates the performance of an intrinsic capacitance of a section of the microprocessor. All of the elements of the model are connected in parallel.
    Type: Grant
    Filed: March 28, 2001
    Date of Patent: December 13, 2005
    Assignee: Sun Microsystems, Inc.
    Inventors: Claude R. Gauthier, Brian W. Amick
  • Patent number: 6975976
    Abstract: Simulation continues to be the primary technique for functional validation of designs. It is important that simulation vectors be effective in targeting the types of bugs designers expect to find rather than some generic coverage metrics. The focus of this work is to generate property-specific testbenches that are targeted either at proving the correctness of a property or at finding a bug. It is based on performing property-specific analysis on iteratively less abstract models of the design in order to obtain interesting paths in the form of a Witness Graph, which is then targeted during simulation of the entire design. This testbench generation framework will form an integral part of a comprehensive verification system currently being developed.
    Type: Grant
    Filed: October 23, 2000
    Date of Patent: December 13, 2005
    Assignee: NEC Corporation
    Inventors: Albert E. Casavant, Aarti Gupta, Pranav Ashar
  • Patent number: 6973420
    Abstract: A self-resetting circuit is simulated in a switch-level simulator using simulation models that can conditionally treat an unknown value on an input node as a known value. An attribute is included with the simulation model. The attribute specifies to the simulator whether to treat an unknown value as a logical zero or a logical one. A single attribute can be associated with the simulation model, or one attribute can be associated with each input node. Self-resetting circuits can be simulated from an initial state that includes unknown states. The proper logical initialization behavior can be simulated while still allowing the self-resetting circuit to propagate unknown states during normal operation and simulation.
    Type: Grant
    Filed: June 30, 2000
    Date of Patent: December 6, 2005
    Assignee: Intel Corporation
    Inventor: Thomas A. Tetzlaff
  • Patent number: 6973417
    Abstract: A method and system for simulating the execution of a software program on a simulated hardware system. An instrumented software program is divided into program segments delineated by tags and is then analyzed for data describing the program segments. The data is tabulated and indexed in a function data table according to the program segments. Hardware parameters that at least define a portion of the simulated hardware system are tabulated in a hardware configuration file. The software program is executed on a host system, and when a tag is executed, data indexed in the function data table under the program segment corresponding to the executed tag and hardware parameters tabulated in the hardware configuration file are used to calculate an estimated execution time for the program segment corresponding to the executed tag. The estimated execution time for the program segment is added to a running total for the overall execution time of the software program.
    Type: Grant
    Filed: November 5, 1999
    Date of Patent: December 6, 2005
    Assignee: Metrowerks Corporation
    Inventors: Sidney Richards Maxwell, III, Michael Louis Steinberger
  • Patent number: 6973635
    Abstract: A printed wiring board design aiding system comprises a first unit which acquires design layout information regarding a printed wiring board targeted for design, a second unit which acquires setting parameter information for the printed wiring board, which is targeted for design, and a third unit which estimates a value of the thickness of each of insulation layers of the printed wiring board in a post-manufacture state in accordance with the information acquired by the first unit and the information acquired by the second unit, and for outputting an estimated value.
    Type: Grant
    Filed: July 23, 2003
    Date of Patent: December 6, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Akihiko Happoya
  • Patent number: 6973422
    Abstract: A netlist model of a physical circuit is provided. The netlist model includes a virtual delay element, wherein the virtual delay element is coupled to an asynchronous circuit element.
    Type: Grant
    Filed: March 20, 2000
    Date of Patent: December 6, 2005
    Assignee: Intel Corporation
    Inventors: Sitaram Yadavalli, Sandip Kundu
  • Patent number: 6973421
    Abstract: A design and verification aide that can be used to produce BZ codes under static or dynamic process, voltage, temperature and external reference resistor (PVT and R) conditions for impedance controlled buffers or any other application using BZ codes. The simulation technique follows that of a flash ADC, and effectively replaces an awkward state-machine BZ controller with a subcircuit consisting of 5 BZREFN's, 5 BZREFP's, 10 HSPICE behavioral comparators, and the BZVREF. The resulting N- and P-codes may be adjusted by a parameterized dither count with minimum and maximum code values enforced by the model, and the comparators can be modified to model offset voltage.
    Type: Grant
    Filed: August 21, 2001
    Date of Patent: December 6, 2005
    Assignee: LSI Logic Corporation
    Inventor: Kevin J. Bruno
  • Patent number: 6970811
    Abstract: Via simple electronic circuitry, an analog voltage that tracks the LED light output is produced. This analog voltage is read by an A/D converter to ascertain an approximate relative light output of the LED so that light output compensation can be quickly calculated. A resistor-capacitor circuit is used to approximate the behavior of the LED light output. The output voltage from this circuit is sampled and used along with a sensed ambient temperature to adjust the exposure time of an image capture system.
    Type: Grant
    Filed: March 22, 2000
    Date of Patent: November 29, 2005
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Paul A. Boerger, Keith Forrest
  • Patent number: 6970814
    Abstract: A method and structure for simulating a circuit comprising inputting, from a customer site, initial memory states, and initial input signals to core logic within a host site, simulating the circuit utilizing the host site and the customer site connected though a wide area network (wherein the host site contains the core logic and the customer site contains customer logic, the core logic and the customer logic forming the circuit), comparing test output signals with the desired output signals, and altering the customer logic until the test output signals are consistent with the desired output signals.
    Type: Grant
    Filed: March 30, 2000
    Date of Patent: November 29, 2005
    Assignee: International Business Machines Corporation
    Inventors: Carl L. Ashley, Charles N. Choukalos, Scott A. Tetreault
  • Patent number: 6968523
    Abstract: An algorithm of a logic circuit is converted from an operation description having operators into a data flow graph having operation nodes executing the operators arranged in order of the executing. Execution steps are allocated in the data flow graph, and registers storing output data from the operation nodes are inserted after execution of the execution steps. A data path of the logic circuit having operation units which served as the operation nodes and storage elements which served as the registers, and control information on the data path are produced. An operator/operation unit database configured to retrieve the operation units executing the operators from the operators and configured to retrieve the operators outputting data stored in the registers which served as the storage elements from the execution steps and the storage elements are produced.
    Type: Grant
    Filed: August 19, 2003
    Date of Patent: November 22, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Atsushi Masuda
  • Patent number: 6968305
    Abstract: A method and apparatus for creating a memory model for use in modeling a physical memory of an electronic circuit design. Memory write operations to the physical memory and memory read operations are modeled in a lookup table. The number of entries in the lookup table is limited by an upper bound representing a total number of memory operations that can occur over a given number of clock cycles.
    Type: Grant
    Filed: June 2, 2000
    Date of Patent: November 22, 2005
    Assignee: Averant, Inc.
    Inventor: Adrian J. Isles
  • Patent number: 6968303
    Abstract: A method is provided for configuring a final data set to use for modeling a manufacturing process, the method including requesting a real-time data set from a real-time database, requesting an historical data set from an historical database, and defining a required format for the final data set. The method also includes combining the real-time data set from the real-time database with the historical data set from the historical database using the required format for the final data set.
    Type: Grant
    Filed: April 13, 2000
    Date of Patent: November 22, 2005
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Qingsu Wang, Elfido Coss, Jr.
  • Patent number: 6965853
    Abstract: A back annotation apparatus, which effectively carries out a back annotation, includes: a pre-layout simulation implementing part for detecting nodes of which the potential changes when a predetermined signal is applied to a logic circuit; a layout pattern verification implementing part for implementing a predetermined layout pattern verification for layout patterns of the logical circuit; a parasitic element extraction part connected to the pre-layout simulation implementing part which extracts parasitic elements from the nodes of which the potential changes; a net list generation part connected to the parasitic element extraction part for generating a net list which includes all the devices included in the layout pattern data and parasitic elements extracted in the parasitic element extraction part; and a post layout simulation implementing part connected to the net list generation part for implementing a post layout simulation by using the net list.
    Type: Grant
    Filed: February 2, 2001
    Date of Patent: November 15, 2005
    Assignee: Renesas Technology Corp.
    Inventors: Hiroyuki Kuzuma, Terutoshi Yamasaki
  • Patent number: 6966040
    Abstract: One embodiment of the present invention relates to a method for constructing a circuit for controlling an electromagnetic actuator. Another embodiment of the present invention relates to a method for designing a circuit for controlling an electromagnetic actuator.
    Type: Grant
    Filed: August 5, 2003
    Date of Patent: November 15, 2005
    Assignee: Combustion Dynamics Corp.
    Inventor: Murad Ismailov
  • Patent number: 6965852
    Abstract: A driver module is provided that generates test patterns with desired tendencies. The driver module provides these test patterns to controlling code for simulation of a hardware model. The test patterns are generated by creating and connecting subgraphs in a Markov chain. The Markov model describes a plurality of states, each having a probability of going to at least one other state. Markov models may be created to determine whether to drive an interface in the hardware model and to determine the command to drive through the interface. Once the driver module creates and connects the subgraphs of the Markov models, the driver module initiates a random walk through the Markov chains and provides the commands to the controlling code.
    Type: Grant
    Filed: December 15, 2000
    Date of Patent: November 15, 2005
    Assignee: International Business Machines Corporation
    Inventor: Jeffrey Adam Stuecheli
  • Patent number: 6961689
    Abstract: In the simulation of an analog and mixed-signal analog-digital physical circuit, events are assigned scheduled times. The events are stored in buckets in a hash table, with the scheduled times of the events in each bucket associated with the bucket. The scheduled times are organized into a heap, with the earliest scheduled time at the root of the heap. The earliest scheduled time is removed from the heap, and the events in the associated bucket are performed. Performing the scheduled events can cause new events to be scheduled, and existing events to be de-scheduled. When all the events in the bucket associated with the earliest scheduled time are simulated, the remaining scheduled times are re-organized into a new heap, and the steps of removing the earliest scheduled time, performing the scheduled events, and re-organizing the remaining scheduled times are repeated.
    Type: Grant
    Filed: March 21, 2000
    Date of Patent: November 1, 2005
    Assignee: Synopsys, Inc.
    Inventor: Steven S. Greenberg
  • Patent number: 6959271
    Abstract: A method is described for identifying an inaccurate model of a hardware circuit. The method includes the steps of simulating the model of the circuit by applying a plurality of signals, said plurality of signals having at least one abstract data type level to provide a set of expected results, replacing the at least one abstract data type level with two or more levels having different values to thereby provide and expanded set of signals to apply to said model, resimulating the model with said expanded set and comparing the two sets of results and providing an output signal indicating if the model is inaccurate if the results contradict.
    Type: Grant
    Filed: October 19, 2000
    Date of Patent: October 25, 2005
    Assignee: STMicroelectronics Limited
    Inventor: Peter Ballam
  • Patent number: 6957176
    Abstract: The invention relates to a reduction processing method including a step for eliminating an “inside-out side”, contained in the sides of an offset figure generated by sizing a source figure. The inside-out side detected by the presence of a first intersection point at which adjacent offset locus line segments intersect. The step includes i) deleting the offset vertices each of which is located at one end of one of the offset locus line segments intersecting at the first intersection point, and ii) revising the offset figure by finding a second intersection point at which offset figure line segments, which form the offset figure by joining the offset vertices, intersect each other, and by setting the second intersection point at the position of the detected offset vertices as an offset vertex.
    Type: Grant
    Filed: June 21, 2001
    Date of Patent: October 18, 2005
    Assignee: Shinko Electric Industries Co., Ltd.
    Inventor: Keiji Yoshizawa
  • Patent number: 6957404
    Abstract: A method for verifying a property of a complete model of a system under study includes abstracting at least some of the variables from the model so as to produce an abstract model of the system. Beginning with an initial state in a state space of the abstract model, an abstract path is found through the state space of the abstract model in accordance with the transition relation to a target state defined by the property. A subset of the abstracted variables is restored to the abstract model so as to produce an intermediate model of the system, and the property on the complete model is verified based on the intermediate model.
    Type: Grant
    Filed: December 20, 2002
    Date of Patent: October 18, 2005
    Assignee: International Business Machines Corporation
    Inventors: Danny Geist, Anna Gringauze, Sharon Keidar
  • Patent number: 6954723
    Abstract: There is disclosed a method comprising: calculating a band gap narrowing of a semiconductor and an ionization rate of an impurity in an equilibrium state; calculating a movable electric charge density contributing to transportation of an electric charge inside the semiconductor by solving a Poisson equation and a movable electric charge continuous equation based on the calculated ionization rate in the equilibrium state; calculating said band gap narrowing and said ionization rate in a non-equilibrium state, taking presence of a potential into consideration, based on the calculated movable electric charge density; and repeating the calculation of the movable electric charge density by solving the Poisson equation and the movable electric charge continuous equation based on the ionization rate and the band gap narrowing in said non-equilibrium state, and the calculation of said band gap narrowing and said ionization rate based on the calculation result, until the ionization rate and the band gap narrowing in s
    Type: Grant
    Filed: September 20, 2001
    Date of Patent: October 11, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Watanabe, Kazuya Matsuzawa
  • Patent number: 6952664
    Abstract: A system and methods for simulating the performance (e.g., miss rate) of one or more caches. A cache simulator comprises a segmented list of buffers, with each buffer configured to store a data identifier and an identifier of the buffer's segment. Data references, which may be copied from an operational cache, are applied to the list to conduct the simulation. Initial estimates of each cache's miss rate include the number of references that missed all segments of the list plus the hits in all segments not part of the cache. A correction factor is generated from the ratio of actual misses incurred by the operational cache to the estimated misses for a simulated cache of the same size as the operational cache. Final predictions are generated by multiplying the initial estimates by the correction factor. The size of the operational cache may be dynamically adjusted based on the final predictions.
    Type: Grant
    Filed: April 13, 2001
    Date of Patent: October 4, 2005
    Assignee: Oracle International Corp.
    Inventors: Tirthankar Lahiri, Juan R. Loaiza, Arvind Nithrakashyap, William H. Bridge
  • Patent number: 6950996
    Abstract: A method of determining a circuit response (such as delay or slew) from a ramp input of an RC circuit calculates two circuit response parameters using a given circuit response metric based on a step input for the RC circuit, and extends the circuit response metric to a ramp input of the RC circuit by combining the first and second circuit response parameters to yield an estimated ramp response. The novel technique is based on the use of probability distribution functions and cumulative distribution functions to characterize the impulse response of the RC circuit, and the calculating steps derive the first and second circuit response parameters from such statistical distribution functions. In particular, the calculating steps may use a standard deviation or a mean of a probability distribution function corresponding to the circuit response parameter. In one application, the invention is used to estimate delay response for the ramp input of the RC circuit.
    Type: Grant
    Filed: May 29, 2003
    Date of Patent: September 27, 2005
    Assignee: International Business Machines Corporation
    Inventors: Charles Jay Alpert, Anirudh Devgan, Chandramouli V. Kashyap, Ying Liu