Circuit Simulation Patents (Class 703/14)
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Patent number: 6950996Abstract: 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: GrantFiled: May 29, 2003Date of Patent: September 27, 2005Assignee: International Business Machines CorporationInventors: Charles Jay Alpert, Anirudh Devgan, Chandramouli V. Kashyap, Ying Liu
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Patent number: 6944582Abstract: A method of designing a memory device that has substantially reduced bitline voltage offsets is provided. The method includes providing a memory core having a depth that defines a plurality of words, and a word width that is defined by multiple pairs of a global bitline and a global complementary bitline. The method also includes designing a core cell having a bitline and a complementary bitline, and designing a flipped core cell that has a flipped bitline and a flipped complementary bitline. Further, the method includes arranging a core cell followed by a flipped core cell along each of the multiple pairs of the global bitline and the global complementary bitline. Preferably, the bitline of the core cell is coupled with the flipped complementary bitline of the flipped core cell, and the complementary bitline of the core cell is coupled to the flipped bitline of the flipped core cell.Type: GrantFiled: December 17, 2001Date of Patent: September 13, 2005Assignee: Artisan Components, Inc.Inventor: Scott T. Becker
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Patent number: 6944837Abstract: A system and method for evaluating a device under test (DUT) that utilizes a model of the DUT interfaced to DUT interface logic, which is designed to interface the DUT to automated testing equipment (ATE). By ensuring that the model includes a description of the DUT and of the DUT testing interface, conditions such as connections between ports of the IC (i.e., buddying) that may or may not be interfaced to the ATE may be included in the model to enable precise test pattern sets to be generated using the model. The test pattern sets may be used by a simulator to test the design of an IC or by ATE to test a fabricated IC having the design.Type: GrantFiled: December 20, 2002Date of Patent: September 13, 2005Assignee: Agilent Technologies, Inc.Inventors: John G Rohrbaugh, Jeff Rearick, Christopher M Juenemann
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Patent number: 6944552Abstract: One embodiment of the invention is a method for analyzing power in a component comprising determining a plurality of current densities, wherein each current density is associated with one portion of a plurality of portions of the component, determining a plurality of wire densities, wherein each wire density is associated with one region of a plurality of regions of the component, and comparing the plurality of current densities and the plurality of wire densities.Type: GrantFiled: June 25, 2003Date of Patent: September 13, 2005Assignee: Hewlett-Packard Development Company, L.P.Inventors: Erin Francom, Gregory D. Rogers
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Patent number: 6944844Abstract: A critical dimension, or width, of a feature, or a semiconductor device, can be measured to provide direct and meaningful information regarding the impact of line end shortening, or length, on the function of the device. Specifically, a location on the feature where the width will have an impact on device performance can be selected. Using a simulation, the width at that location can be computed. Given the difficulties of direct measurement of line end shortening and the relationship between the width measurement and the impact on device performance, better layout checking is facilitated than by standard measurements of line end shortening.Type: GrantFiled: April 3, 2002Date of Patent: September 13, 2005Assignee: Synopsys, Inc.Inventor: Hua-Yu Liu
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Patent number: 6944838Abstract: A design verifier includes a bounded model checker, a proof partitioner and a fixed-point detector. The bounded model checker verifies a property to a depth K and either finds a counterexample, or generates a proof in the form of a directed acyclic graph. If a counterexample is found, the bounded model checker selectively increases K and verifies the property to the new larger depth using the original constraints. If no counterexample is found, the proof partitioner provides an over-approximation of the states reachable in one or more steps using a proof generated by the bounded model checker. The fixed-point detector detects whether the over-approximation is at a fixed point. If the over-approximation is at a fixed-point, the design is verified. If the over-approximation is not at a fixed point, the bounded model checker can iteratively use over-approximations as a constraint and verify the property to a depth K.Type: GrantFiled: February 3, 2003Date of Patent: September 13, 2005Assignee: Cadence Design Systems, Inc.Inventor: Kenneth L. McMillan
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Patent number: 6941256Abstract: With respect to each application, libraries, corresponding to operation models, for describing operations respectively attained by employing a Neumann CPU (bus structure), a Harvard CPU (bus structure) and a direction separate type CPU (bus structure) are registered. In a performance table of each library, the performance index of the library is expressed as a function of parameters of throughput, a bus width, instruction quantity and memory size. Also, a portion of the operation realized by using software and a portion realized by using hardware are registered. Through operation simulation conducted with each application successively replaced with each of the libraries, the performance of a semiconductor integrated circuit can be evaluated, so as to synthesize an optimal interface.Type: GrantFiled: July 20, 2000Date of Patent: September 6, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventor: Makoto Fujiwara
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Patent number: 6941258Abstract: A simulation system is described for computing the overall signal generated in a substrate by a digital system comprising a plurality of gates associated with the substrate, wherein each gate is configured to perform a switching event. Output of a transistor-level model is compared with output of a lumped circuit model for each gate and the substrate, and signal contributions from each gate and switching event are determined based on the comparison. The system determines switching event signals for each of the plurality of gates. The signal contributions and the switching event signals are combined, and a combined lumped circuit model is derived based on a combination of lumped circuit models of the plurality of gates. The overall signal is computed based on the combined gate signal contributions and switching event signals, which are configured as an input to the combined lumped circuit model.Type: GrantFiled: March 16, 2001Date of Patent: September 6, 2005Assignee: Interuniversitair Microelektronica CentrumInventors: Marc Van Heijningen, Mustafa Badaroglu
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Patent number: 6941257Abstract: A method, system, and data structure for instrumenting a cross-hierarchical simulation event are disclosed herein. The cross-hierarchical simulation event is a function of a first simulation event residing at a first level of simulation model hierarchy and a second simulation event residing at a second level of simulation model hierarchy. In accordance with the present invention, a cross-hierarchical instrumentation entity is defined within the first level of simulation model hierarchy utilizing an instrumentation declaration comment containing data representing a cross-hierarchical instrumentation entity. A first input of said instrumentation entity is connected to the first simulation event and a second input of the instrumentation entity is connected to the second simulation event utilizing an input port mapping comment that declares the cross-hierarchical instrumentation entity to generate a cross-hierarchical simulation event.Type: GrantFiled: December 30, 2000Date of Patent: September 6, 2005Assignee: International Business Machines CorporationInventors: Wolfgang Roesner, Derek Edward Williams
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Patent number: 6937973Abstract: A method of operating a computer system to design an application specific processor (ASP) comprises defining a set of peripherals for the ASP which are responsive to stimuli and which communicate with a processor, generating for each peripheral an input file which defines the functional attributes of that peripheral in a high level language with an input data structure, entering the input file into the computer system and operating a modelling tool loaded on the computer system to generate from the input file a register definition file by allocating specific elements of the input data structure to predefined sectors of a register definition table, and using the register definition file to create in silicon the registers of the ASP.Type: GrantFiled: June 28, 1999Date of Patent: August 30, 2005Assignee: STMicroelectronics LimitedInventor: Gajinder Singh Panesar
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Patent number: 6937965Abstract: A method for creating a guardband that incorporates statistical models for test environment, system environment, tester-to-system offset and reliability into a model and then processes a final guardband by factoring manufacturing process variation and quality against yield loss.Type: GrantFiled: March 7, 2000Date of Patent: August 30, 2005Assignee: International Business Machines CorporationInventors: Mark R. Bilak, Joseph M. Forbes, Curt Guenther, Michael J. Maloney, Michael D. Maurice, Timothy J. O'Gorman, Regis D. Parent, Jeffrey S. Zimmerman
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Patent number: 6938224Abstract: A method of predicting the electromagnetic noise emitted by a digital circuit on an integrated circuit is disclosed. In accordance with the illustrative embodiment, the output of each digital circuit element in the digital circuit is considered as a bit stream. All of these bits streams are, in aggregate, considered as a noise source that is characterized by a power spectral density, S(?). The effect of the noise source on an analog circuit can be modeled as a lumped circuit, wherein the lumped circuit contains a noise source that represents the digital circuit; a multi-port network, also referred to as a lumped element, that represents that portion of the substrate between the digital circuit and the analog circuit; and a multi-port network that represents the analog circuit.Type: GrantFiled: February 20, 2002Date of Patent: August 30, 2005Assignee: Lucent Technologies Inc.Inventors: Thaddeus John Gabara, Samuel Suresh Martin
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Patent number: 6937969Abstract: Simulation methods and simulators are presented which operate on a computer under software control. Said computer simulation methods and simulators are specially suited for simulating digital circuits and mixed analog digital circuits. The methods enable efficient simulation, meaning resulting in a fast simulation while still obtaining accurate results. With fast simulation is meant that the simulation can be completed in a short simulation time. Accurate means that the signals obtained or determined by simulation are good approximations of the signals that would be measured when the circuit, which representation is under simulation, is actually running in real world. Indeed the simulation methods and the related simulation apparatus or simulator exploits a representation of a circuit.Type: GrantFiled: June 9, 2000Date of Patent: August 30, 2005Assignees: Interuniversitair Microelektronica Centrum (IMEC), Vrije Unirversiteit BrusselInventors: Gerd Vandersteen, Pierre Wambacq, Yves Rolain, Petr Dobrovolny
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Patent number: 6938228Abstract: A method and apparatus for simulating multiple stimuli using symbolic encoding. In one embodiment, the method comprises encoding a plurality of sets of stimulus to create a symbolic stimulus, symbolically simulating a device under test, including applying the symbolic stimulus to the device under test, and outputting a symbolic result from the device under test in response to the symbolic stimulus.Type: GrantFiled: July 19, 2002Date of Patent: August 30, 2005Assignee: Synopsys, Inc.Inventor: John Xiaoxiong Zhong
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Patent number: 6937970Abstract: A method is provided of transferring data from a sender process to a plurality of receiver processes in a hardware description language, which uses a language construct which effects synchronised communication between the sender process and the receiver processes.Type: GrantFiled: May 26, 2000Date of Patent: August 30, 2005Assignee: Sharp Kabushiki KaishaInventors: Andrew Kay, Paul Philip Boca, Ryoji Sakurai
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Patent number: 6933731Abstract: According to one embodiment, a method for isolating degradation mechanisms in transistors includes providing a ring oscillator having a plurality of delay elements. Each delay element operates as a delay element through the use of one or more transistors of only a first type and no transistors of the opposite type. The method further includes operating the ring oscillator and measuring the frequency resulting from the ring oscillator over time. The magnitude of an isolated degradation mechanism is determined based on a comparison of the measured frequency and an expected frequency for the ring oscillator absent degradation.Type: GrantFiled: October 17, 2003Date of Patent: August 23, 2005Assignee: Texas Instruments IncorporatedInventors: Vijay Kumar Reddy, Robert L. Pitts
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Patent number: 6934671Abstract: A method of performing model to hardware correlation that simulates models based upon design criteria and manufactures devices based upon the design criteria. The method evaluates features of the devices during the manufacturing to produce in-line test parametric data, compares the models to the in-line test parametric data to obtain correlation data, and modifies the simulating according to the correlation data.Type: GrantFiled: May 29, 2001Date of Patent: August 23, 2005Assignee: International Business Machines CorporationInventors: John E. Bertsch, Daniel S. Coops, David M. Fried
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Patent number: 6934670Abstract: A method of and an apparatus for designing a test environment and of evaluating performance of the test environment and an electronic device during testing of the electronic device. A virtual test environment is created emulating an actual test environment. A virtual device emulating the actual electronic device is implanted into the virtual test environment, and that virtual device is stimulated with an input test signal emulating the actual input signal applied to the actual electronic device in the actual test environment. The integrity of the input test signal and the resulting output signal is evaluated. An adjustment might be made to the virtual calibration of the virtual test environment and/or to the virtual device, or both, and the design of the actual device might be improved. The invention can be implemented on a properly programmed general purpose processing system or on a special purpose system.Type: GrantFiled: March 30, 2001Date of Patent: August 23, 2005Assignee: Intel CorporationInventors: Sunil K. Jain, Gregory P. Chema
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Patent number: 6934672Abstract: A system provides primary and alternate control circuits to a controlled system through an output port. A monitoring circuit that monitors a parameter of the controlled system selects the control methodology. The primary control circuit, consisting of a primary active part and a regulator, and an alternate control circuit receive feedback from the controlled system. A switching mechanism, controlled by an output of the monitoring circuit, connects the appropriate control circuit to the controlled system and switches internal connections as needed. During alternate mode, a simulator of the controlled system as driven by the primary active control circuit provides an output representative of the output of the regulator that would cause the current output of the controlled system if the system were in primary mode. This simulator output is used when transitioning back to primary mode to minimize transients in the output of the controlled system.Type: GrantFiled: December 27, 2001Date of Patent: August 23, 2005Assignee: Texas Instruments IncorporatedInventor: Kurt F. Hesse
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Patent number: 6934669Abstract: A method and apparatus for determining capacitance of wires in an integrated circuit is described. The capacitance information derived according to the invention can be used, for example, to calibrate a parasitic extraction engine or to calibrate an integrated circuit fabrication process. The capacitance information can also be used for timing and noise circuit simulations, particularly for deep sub-Micron circuit design simulations. Briefly, the invention allows measurement of both total capacitance of a line and cross coupling capacitance between two lines by applying predetermined voltage signals to specific circuit elements. The resulting current allows simple computation of total capacitance and cross coupling capacitance. Multiple cross coupling capacitance can be measured with a single device, thus improving the art of library generation, and the overall method is free of uncertainties related to transistor capacitance couplings.Type: GrantFiled: August 26, 1999Date of Patent: August 23, 2005Inventors: Roberto Suaya, Sophie H. M. Gabillet
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Patent number: 6931369Abstract: A method and apparatus for thermally simulating a circuit over a network is provided. Techniques are provided for designing a circuit that satisfies user-specified functional requirements received over a network. Based on the specified requirements, components and a topology for constructing the circuit are automatically determined. The components determined during this operation have operational values such that, when the components are arranged according to the topology to form the circuit, the circuit satisfies the user-specified functional requirements. One or more web pages that identify the components are then delivered to the browser over the network. The component and topology information may be used to generate a schematic diagram that is delivered in a web page to the user over the network. The user may thermally simulate the designed circuit. Many characteristics of the board may be adjusted to provide an accurate thermal simulation.Type: GrantFiled: May 1, 2001Date of Patent: August 16, 2005Assignee: National Semiconductor CorporationInventors: Jeffrey Robert Perry, Martin Garrison, Rex L. Allison, III, Richard Levin, Phil Gibson, Vandana A. Sojrani, Khang Nguyen, Wanda Carol Garrett, John D. Perzow
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Patent number: 6928636Abstract: A rule-based OPC evaluating method and a simulation-based OPC model evaluating method for accurately evaluating line width controllability are disclosed. Mask pattern design data about an evaluation-use mask are input to rule-based OPC to obtain correction data about the mask pattern on the evaluation-use mask. An evaluation-use wafer is fabricated based on the correction data thus acquired. Gate patterns on the evaluation-use wafer are measured for size. Based on a simulation-based OPC model having undergone process calibration, simulation data are output corresponding to all gate patterns on the evaluation-use wafer. The measured data about the evaluation-use gate patterns are compared with the simulation data, whereby the rule-based OPC is evaluated.Type: GrantFiled: May 10, 2002Date of Patent: August 9, 2005Assignee: Sony CorporationInventor: Hidetoshi Ohnuma
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Patent number: 6928401Abstract: An interactive repeater insertion simulator (IRIS) system and method quickly and easily optimize the design of an integrated circuit (IC) interconnect for an electrical signal through the insertion of repeaters. The IRIS system utilizes the combination of a router, a repeater inserter, and a delay simulator to efficiently simulate repeater insertion. The router defines the route between more than one circuit and derives a first netlist. The first netlist is then sent to the repeater inserter to define the insertion of repeaters. A second netlist is outputted from the repeater inserter having thereupon one or more repeaters, inserted, and the physical locations of these repeaters along the interconnect for optimal performance, and minimum propagation delay. The delay simulator is then run on the second netlist to calculate the new interconnect delays. The interconnect delays may then be plotted or otherwise output for examination.Type: GrantFiled: June 10, 1999Date of Patent: August 9, 2005Assignee: Hewlett-Packard Development Company, L.P.Inventor: John D Wanek
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Patent number: 6925427Abstract: A method of determining a switch sequence plan for an electrical system includes the steps of identifying switches for the electrical system and organizing the identified switches within a switch group by defining a coincident group of switches to be closed together or a sequential group of switches to be closed one at a time and by defining a duration of time the switches should be closed. The method also includes the steps of organizing the switch group in a data tree structure for the switch sequence plan and traversing the data tree structure recursively to calculate opening and closing times for the switches within the switch sequence plan. The method further includes the steps of generating a simulation command for setting a position sequence of the switches from the opening and closing times for the switch sequence plan and using commands within the switch sequence plan to operatively control the switches in a simulation of the electrical system.Type: GrantFiled: April 4, 2000Date of Patent: August 2, 2005Assignee: Ford Global Technologies, LLCInventor: Thomas Anthony Montgomery
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Patent number: 6925406Abstract: A scan test viewing and analysis tool for an integrated circuit tester provides inter-related views of scan tests on an integrated circuit device. The tool processes a test program specification, execution results and device definition to produce cross-referencing data, which the tool then uses to provide navigation links between correlated locations in a cyclized test view, procedural test program view, and views of signal vectors, scan state and scan vectors. The tool also provides a capability to edit the test program in the views.Type: GrantFiled: June 19, 2003Date of Patent: August 2, 2005Assignee: Teseda CorporationInventors: David S. Kellerman, Steven R. Morris, Andrew H. Levy
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Patent number: 6925429Abstract: An electric wiring simulation device 1 of the present invention includes an input device 2; a display 5; a characteristics information data base 4 storing parts information on parts and wirings, discharge characteristics of a power supply, current-prearcing time characteristics of protecting parts and current-smoke time characteristics of the wirings; an assigned path searching unit 11 searching an assigned path between a short-circuit point and the power supply on a test object circuit; a current value calculating unit 12 calculating a resistance value on the assigned path based on the parts information, and calculating a short-circuit value based on the resistance value and the discharge characteristics of the power supply; and a judging unit 13 judging whether or nor each protecting part is fused or etch wiring smokes based on the current-smoke time characteristics and the current-prearcing time characteristics, at unit time intervals.Type: GrantFiled: July 3, 2001Date of Patent: August 2, 2005Assignee: Yazaki CorporationInventor: Yasuo Iimori
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Patent number: 6922821Abstract: Checking the consistency of a lock step process while debugging a microcontroller code is in progress. A method provides a production microcontroller to execute an instruction code and provides the result of the instruction code to an ICE. The ICE, independent from the production microcontroller and simultaneously, executes the same instruction code and produces a result. The ICE compares the result of its computation and the result received from the production microcontroller. The ICE issues a “lock step error” when the result of the comparison is a mismatch. A trace buffer residing in the host device provides the location of the line of code causing the mismatch. After identifying the line of code causing the mismatch the user debugs the erroneous line of code. The debugging process resumes on the next line of code in the microcontroller code under test.Type: GrantFiled: November 15, 2001Date of Patent: July 26, 2005Assignee: Cypress Semiconductor Corp.Inventor: Craig Nemecek
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Patent number: 6922665Abstract: A method and system for simulating a circuit design for a programmable logic device (PLD) at the device level. The same configuration data that is used to configure a PLD is used to generate objects that represent configurable logic elements of the PLD. During simulation, events are generated based on changes in output signal states of the objects. Each event includes an input signal state and identifies an object to which the input signal is to be applied. Since configurable logic elements are simulated, for example, lookup tables, instead of logic gates, fewer events need to be generated and processed than in a conventional simulator. In another embodiment, the system supports an interface that allows tools to interface with the simulator in the same manner as the tools interface with a PLD.Type: GrantFiled: January 8, 2001Date of Patent: July 26, 2005Assignee: Xilinx, Inc.Inventors: Steven A. Guccione, Scott P. McMillan, Brandon J. Blodget
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Patent number: 6920418Abstract: A system, method, and data structure for providing an efficient means for monitoring model events. The present invention generates detection events that are accessible by the RTX. Such detection events are generated by instrumentation entities. Detection events are implemented as output ports on an instrumentation entity. Furthermore, the present invention discloses an enhanced API function for directly accessing detection events within a given simulation model.Type: GrantFiled: December 30, 2000Date of Patent: July 19, 2005Assignee: International Business Machines CorporationInventors: Wolfgang Roesner, Derek Edward Williams
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Patent number: 6917909Abstract: Guidance provision to the creation of an electronic design is facilitated through a method that includes facilitating interactive exploration of the electronic design by a designer to aid the designer in formulating his/her guidance, and facilitating the designer in interactively providing the formulated guidance. In one embodiment, facilitation of interactive exploration by the designer include facilitating interactive cross-probing into a number of issues about the design, including generated candidate architectures for the design. In one embodiment, the issues available for cross probing include inter-dependencies of data and mobility of operations of the design, as well as occupation of hardware resources for the generated candidate architectures. In one embodiment, Gantt diagrams are employed to facilitate navigation by the designer in performing the interactive cross probing. Gantt diagrams graphically representing the generated candidate architectures are selectively presented to the designer.Type: GrantFiled: May 18, 1998Date of Patent: July 12, 2005Inventors: Lev A. Markov, Ian Andrew Guyler, Shiv Prakash, David G. Burnette
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Patent number: 6915410Abstract: A system for designing and implementing digital integrated circuits utilizing a set of synchronized sequencers that permit quick and efficient parallel processing of system level designs. The system and method converts digital schematics and hardware description language (HDL) based designs into a set of logic equations and single bit arithmetic-logic operations executed by a set of parallel operating sequencers. The system includes software for converting netlists and HDL designs into Boolean logic equations, and a compiler for distributing these logic equations between multiple sequencers. Each sequencer is comprised of a logic processor and the associated program memory for storing the executable code of the assigned Boolean logic equations and data memory for storing the results of processing of logic equations. To synchronize execution of logic equations by multiple sequencers, all program memories are addressed by one common address register.Type: GrantFiled: January 23, 2003Date of Patent: July 5, 2005Inventor: Stanley M. Hyduke
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Patent number: 6915249Abstract: In order to achieve augmentation of the accuracy in calculation of noise and augmentation of the accuracy in a noise check which is performed, for example, when an electronic circuit is designed and further realize significant reduction of the time required for a noise check and augmentation of the operation efficiency by reduction of the man-hours of a designer in a noise analysis, a noise checking apparatus includes a model production section (3) for producing a simulation model of a circuit portion relating to a noticed wiring line, a simulation section (4) for performing a simulation using the simulation model to calculate a signal waveform which propagates in the noticed wiring line and calculate a noise waveform superposed on the signal waveform for each kind of noise, a noise waveform synthesis section (5) for synthesizing the signal waveform and the noise waveforms with generation timings of the noise waveforms taken into consideration to obtain a noise composite waveform, and a noise checking sectionType: GrantFiled: November 9, 2000Date of Patent: July 5, 2005Assignee: Fujitsu LimitedInventors: Toshiro Sato, Yuji Suwa, Yoshiyuki Iwakura, Kazunari Gotou, Toshiaki Sato, Kazuyoshi Kanei, Masaki Tosaka, Yasuhiro Yamashita
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Patent number: 6915250Abstract: A simulation system that simulates a customer premises is disclosed that is tunable. The simulation system is comprised of a communication media simulator system and a device simulator system. The communication media simulator system receives a service provider signal from a service provider. The communication media simulator system applies a load to the service provider signal to simulate a length of communication media. The communication media simulator system varies the load to adjust the length of communication media simulated. The device simulator system applies a second load to the service provider signal to simulate at least one customer premises device.Type: GrantFiled: July 3, 2001Date of Patent: July 5, 2005Assignee: Sprint Communications Company L.P.Inventor: Benjamin J. Parker
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Patent number: 6915251Abstract: A memory device design is provided. The memory device includes a memory core having a depth that defines a plurality of words, and a word width that is defined by multiple pairs of a global bitline and a global complementary bitline. The memory device further includes a core cell having a bitline and a complementary bitline, and a flipped core cell that has a flipped bitline and a flipped complementary bitline. The multiple pairs of the global bitline and the global complementary bitline have a plurality of core cells that are defined by alternating ones of the core cell and the flipped core.Type: GrantFiled: December 17, 2001Date of Patent: July 5, 2005Assignee: Artisan Components, Inc.Inventor: Scott T. Becker
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Patent number: 6915248Abstract: Described is a method for validating a digital design using a simulation process. All possible design states of the design are divided into a plurality of validation regions. In the simulation-process, the method records and updates the simulation history for each of t he validation region. When a particular stimulus is specified by the designer to perform a step of simulation for a current state within one of the validation regions, the process determines simulation efficiency by examining the specified stimulus and the simulation history of the validation region. The method may transform the specified stimulus into a more interesting stimulus to improve the efficiency and coverage of the simulation process.Type: GrantFiled: June 28, 1999Date of Patent: July 5, 2005Assignee: Cadence Design Systems, Inc.Inventor: Chung-Wah Norris Ip
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Patent number: 6912494Abstract: A method is described for reducing delays in an analogue simulation model of a hardware circuit. The method includes the steps of stimulating via an input an output of said analog model, said output and said input having a relatively high resistance therebetween and applying a pulse to a relatively low resistance, whereby when said pulse is applied to the relatively low resistance, the input is connected to said output via the relatively low resistance so that the time constant of the circuit is reduced.Type: GrantFiled: October 19, 2000Date of Patent: June 28, 2005Assignee: STMicroelectronics LimitedInventor: Peter Ballam
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Patent number: 6909976Abstract: A threshold voltage model with an impurity concentration profile in a channel direction taken into account is provided in the pocket implant MOSFET. With penetration length of the implanted pocket in the channel direction and the maximum impurity concentration of the implant pocket used as physical parameters, the threshold voltage model is obtained by linearly approximating the profile in the channel direction. By analytically solving the model by using a new threshold condition with inhomogeneous profile taken into account, the threshold voltage can be accurately obtained. Based on thus obtained model, the threshold voltage can be predicted and can be used for circuit design.Type: GrantFiled: August 30, 2002Date of Patent: June 21, 2005Assignee: Semiconductor Technology Academic Research CenterInventors: Daisuke Kitamaru, Michiko Miura
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Patent number: 6910002Abstract: In one embodiment, a method for specifying addressability in a memory-mapped device is disclosed. A data access primitive is used to model addressablity for the memory-mapped device. Addressability comprises an address matching function, a lane matching function and one or more bus connections. A first starting address for the memory-mapped device is specified. A first set of addressing matching function, lane matching function and one or more bus connections for the memory-mapped device is generated using the data access primitive and the first starting address.Type: GrantFiled: August 23, 2000Date of Patent: June 21, 2005Assignee: Xilinx, Inc.Inventors: Bart Reynolds, Cheng-I Chuang, Chukwuweta Chukwudebe, Sridhar Krishnamurthy, Damon McCormick, Tom Shui, Kai Zhu
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Patent number: 6907586Abstract: A system, method and program product for designing integrated circuits. A design of an integrated circuit (IC) is analyzed to identify the longest path between each pair of registers. A crosstalk overhead is calculated for each identified longest path using a stochastic model. The crosstalk overhead of each longest path is added to selected path delays as an incremental port of register set up time. Any path wherein the sum of the path delay and crosstalk overhead exceeds a maximum accepted delay, i.e., where slack is less than or equal to zero is redesigned and the IC is then, placed and wired. The stochastic model may be a tree-like structure derived from several completed integrated circuit (IC) designs, in particular from cell placement and wiring for the completed IC. The tree-like stochastic model corresponds crosstalk delays to technology wire factors.Type: GrantFiled: October 2, 2001Date of Patent: June 14, 2005Assignee: LSI Logic CorporationInventors: Maad A. Al-Dabagh, Alexander Tetelbaum, Tammy T. Huang
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Patent number: 6907394Abstract: A device for simulating circuits is provided with an identifying system and a verifying system. The identifying system identifies a pair of wires in which two signals operate simultaneously within an appointed period and a pair of wires in which two signals do not operate almost simultaneously within the appointed period. The verifying system verifies actions of a circuit to be analyzed, under an assumption that the coupling capacitor between the pair of wires in which it is judged by the identifying system that two signals do not simultaneously operate within the appointed period is a ground capacitor.Type: GrantFiled: May 12, 2000Date of Patent: June 14, 2005Assignee: Elpida Memory, Inc.Inventor: Mitsuru Sato
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Patent number: 6904397Abstract: A system and method for developing a reusable electronic circuit design module are presented in various embodiments. In one embodiment, the functional design elements comprising a design module are entered into a database along with documentation elements that describe the design elements. The functional design elements are linked with selected ones of the documentation elements in the database. A testbench is simulated with the design module, and the generated results are stored in a database and linked with the functional design elements. By linking the simulation results, documentation, and design elements, the characteristics of the design module are easily ascertained by a designer who is reusing the design module.Type: GrantFiled: February 22, 2000Date of Patent: June 7, 2005Assignee: Xilinx, Inc.Inventors: Carol A. Fields, Anthony D. Williams
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Patent number: 6901358Abstract: A simulation system that simulates a length of communication media is disclosed that is tunable. Examples of communication media include wire, coaxial cable, and fiber. The simulation system is comprised of a communication media simulator system. The communication media simulator system receives a service provider signal from a service provider. The communication media simulator system applies a load to the service provider signal to simulate the length of communication media. The communication media simulator system varies the load to adjust the length of communication media simulated.Type: GrantFiled: July 3, 2001Date of Patent: May 31, 2005Assignee: Sprint Communications Company L.P.Inventor: Benjamin J. Parker
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Patent number: 6901357Abstract: A system and method for simulating network connection characteristics by alteration of a network packet. In general, the method of the present invention includes providing a driver that is capable of accessing all outgoing and incoming network packets and altering a network packet to simulate a connection characteristic of the network. In particular, the method of the present invention includes receiving a network packet, assigning a new, simulated network address to the network packet and performing modification of the network packet to simulate certain network connection characteristics (including, for example, transmission delay, limited bandwidth, packet dropping, packet fragmentation, packet duplication and packet reordering). The system of the present invention includes a modification module for altering certain characteristics of a packet.Type: GrantFiled: December 14, 1999Date of Patent: May 31, 2005Assignee: Microsoft CorporationInventor: Kestutis Patiejunas
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Patent number: 6898561Abstract: Methods, apparatus and computer program products for modeling integrated circuits having dense devices therein that experience linewidth (e.g., gate electrodes) reductions during fabrication are provided. For dense devices having electrical paths therein and first and second gate electrodes that overlie the electrical path, operations include determining an electrical gate length of the first gate electrode by evaluating a change in current through the electrical path relative to a change in gate length of the second gate electrode. The operation to determine the electrical gate length of the first gate electrode includes evaluating a change in simulated drain-to-source current through the electrical path relative to a change in the electrical gate length of the second gate electrode.Type: GrantFiled: December 21, 1999Date of Patent: May 24, 2005Assignee: Integrated Device Technology, Inc.Inventors: Chunbo Liu, Zhijian Ma, Jeong Yeol Choi
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Patent number: 6898767Abstract: Disclosed is a method for converting a SPICE format circuit description to a standard cell HDL netlist, such as Verilog, allowing simulation and verification in HDL format. SPICE elements may be converted to circuit functions and corresponding standard cells are then selected. The SPICE netlist is employed to define timing paths. Timing information from SPICE simulation is correlated with timing characteristics of the standard cells and a standard delay file is produced such that, when applied to the standard cells, timing approximates that of the SPICE simulation. The present invention may also employ SPICE to Verilog conversion wherein a SPICE netlist is converted to a Verilog standard cell netlist. Timing information from SPICE simulation is correlated with timing characteristics of the standard cells in the Verilog netlist and a standard delay file is produced such that, when applied to the standard cells, timing approximates that of SPICE simulations.Type: GrantFiled: May 9, 2002Date of Patent: May 24, 2005Assignee: LSI Logic CorporationInventor: Duncan Halstead
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Patent number: 6895372Abstract: A method and system for visualizing circuit operation. In the method device activity is obtained based on one or more of measured or simulated activity. The device activity is expressed in a representation, and the expressed activity is represented in a visual form. One suitable form of activity is the simulated version of the PICA slow motion movie. The invention may apply to other simulated design data vies as well, such as switch level simulation, current density simulation, and power density simulation.Type: GrantFiled: September 27, 1999Date of Patent: May 17, 2005Assignee: International Business Machines CorporationInventors: Daniel R. Knebel, Mark A. Lavin, Jamie Moreno, Stanislav Polonsky, Pia N. Sanda, Steven H. Voldman
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Patent number: 6895561Abstract: A method for modeling the power behavior of a pipelined processor has been developed. The method uses a power model integrated into a cycle accurate simulator. To create the power model, design blocks of the processor are divided into sub-blocks. Power modeling equations for each sub-block are developed by collaboration between the sub-block circuit designer and the simulator developer, using activity information relevant to the sub-block that is available in the simulator model. Each equation is calculated multiple times with different sets of power parameters to represent varying power conditions. Every simulation cycle, sub-block power is summed to generate full-chip power for multiple power conditions.Type: GrantFiled: December 7, 2001Date of Patent: May 17, 2005Assignee: Sun Microsystems, Inc.Inventors: Miriam G. Blatt, Poonacha Kongetira, David J. Greenhill, Vidyasagar Ganesan
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Patent number: 6895524Abstract: A method for reducing a transistor circuit netlist for clock network timing verification is provided. Further, a simulation tool that reduces a transistor circuit netlist such that nonlinear circuit properties are preserved is provided. Further, a computer system that improves clock network performance by simulating a netlist that is generated from a reduced transistor circuit netlist is provided.Type: GrantFiled: September 28, 2001Date of Patent: May 17, 2005Assignee: Sun Microsystems, Inc.Inventor: Alexander Korobkov
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Patent number: 6892172Abstract: This system represents a customizable simulation model of an ATM/SONET Framer for System Level Verification and Performance-Characterization. An Asynchronous Transfer Mode (ATM) data processing ASIC interfaces with a Media Access Control (MAC) device that presents an electrical data path interface, called Universal Test & Operations PHY Interface for ATM (UTOPIA), using ATM protocol on the ASIC side and simplex optical interfaces using Synchronous Optical Network (SONET) protocol on the network side. Such a MAC device, commonly referred to as ATM/SONET Framer, provides one Receive and one Transmit interface to the network at various SONET line rates such as 155.52 Mbps (OC-3), 622.08 Mbps (OC-12), 2488.32 Mbps (OC-48), etc. The ATM and the SONET interfaces operate on different clock frequencies and thus represent two distinct clocking domains. The data interchange between the two clocking domains is achieved via FIFO buffer elements and associated control and status signals.Type: GrantFiled: February 16, 2000Date of Patent: May 10, 2005Inventors: Raj Kumar Singh, Laura Ann Weaver
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Patent number: 6889366Abstract: The present invention is directed to a system and method for coevolutionary circuit design. A system suitable for providing integrated circuit design may include a memory suitable for storing a first set of instructions and a second set of instructions and a processor communicatively coupled to the memory. The processor is suitable for performing the first set of instructions and the second set of instructions. The first set of instructions is suitable for configuring a processor to provide an integrated circuit development environment in which a support methodology for an integrated circuit is created. The second set of instructions is suitable for configuring a processor to provide tools for implementing a platform architecture of an integrated circuit in which the platform architecture supplies a structure of the integrated circuit.Type: GrantFiled: December 27, 2001Date of Patent: May 3, 2005Assignee: LSI Logic CorporationInventor: Christopher L. Hamlin