# US 5,706,477 A · Circuit simulation model extracting method and device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,706,477 A - Document ID: US5706477A - Status: Granted - Kind: A - Application number: 08/555,710 - Filed: 1995-11-14 - Granted: 1998-01-06 - Earliest claimed: 1994-11-05 - Assignees: Fujitsu Limited - Inventors: Kazunari Goto - Web page: https://patentgrep.com/patent/US5706477A ## CPC - G06F 30/33: Design verification, e.g. functional simulation or model checking - G06F 30/367: Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A memory unit stores logic information expressing a plurality of logic function elements constituting a logic circuit, and wiring information about a plurality of components that correspond to the plurality of logic function elements on a printed circuit board. An extracting unit extracts the wiring information and logic information to be used for executing circuit simulation from among the wiring information and logic information stored in the memory unit. A circuit model conversion unit converts the wiring information and logic information extracted by the extracting unit into a circuit model suitable for executing the circuit simulation. A simulation unit executes the circuit simulation on the basis of the circuit model converted by the circuit model conversion unit, and identifies the electrical characteristics between the plurality of components that correspond to the wiring information and logic information extracted by the extracting unit. ## Claims ### Claim 1 A circuit simulation model extracting device, comprising: a memory unit for storing logic information expressing a plurality of logic function elements constituting a logic circuit, and wiring information about a plurality of components that correspond to the plurality of logic function elements on a printed circuit board wherein the wiring information for a plurality of printed circuit boards includes a driver for performing driving based on signals from a power source, a receiver for receiving the signals, and a net for expressing a wiring that interconnects the driver and the receiver; an extracting unit for extracting the wiring information and the logic information to be used for executing circuit simulation, from among the wiring information and logic information stored in said memory unit, the extracting unit extracting from among the wiring information for the plurality of printed circuit boards stored in the memory unit, the wiring information about the printed circuit boards that is to be used for executing the circuit simulation; a circuit model conversion unit for converting the wiring information and the logic information extracted by said extracting unit into a circuit model suitable for executing the circuit simulation, the circuit model conversion unit comprising: a subcircuit storage unit for storing as circuit simulation data, a power source subcircuit corresponding to the power source, a driver subcircuit corresponding to the driver, a receiver subcircuit corresponding to the receiver, and a line subcircuit corresponding to the net; a power source circuit for reading the power source subcircuit from the subcircuit storage unit; a driver circuit, connected to the power source subcircuit, for converting the driver into the driver subcircuit stored in the subcircuit storage unit; a line circuit, connected to the driver subcircuit, for converting the net into the line subcircuit stored in the subcircuit storage unit; and a receiver circuit, connected to the line subcircuit, for converting the receiver into the receiver subcircuit stored in the subcircuit storage unit; and a simulation unit for executing the circuit simulation based on the circuit model converted by said circuit model conversion unit, and identifying an electrical characteristic between the plurality of components that corresponds to the wiring information and the logic information extracted by the extracting unit. ### Claim 2 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the extracting unit extracts a plurality of nets from the wiring information when the nets are contained in the wiring information; and the line circuit converts a plurality of parts of the nets into a single line, and remaining parts of the nets into a plurality of lines when the parts of the nets extracted by the extracting unit are close to each other. ### Claim 3 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the extracting unit extracts a plurality of nets from the wiring information when the nets are contained in the wiring information; and the line circuit converts a plurality of parts of the nets as capacitors, and remaining parts of the nets into a plurality of lines when the parts of the nets extracted by the extracting unit are orthogonal to each other. ### Claim 4 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the extracting unit extracts a plurality of nets from the wiring information when the nets are contained in the wiring information; and the circuit model conversion unit converts the wiring information into the subcircuits for each of the plurality of nets. ### Claim 5 (depends on 2) A circuit simulation model extracting device as defined in claim 2, wherein the circuit model conversion unit retrieves, for each net, a plurality of parts of the nets as close nets based on the wiring information. ### Claim 6 (depends on 3) A circuit simulation model extracting device as defined in claim 3, wherein the circuit model conversion unit retrieves, for each net, a plurality of parts of the nets as orthogonal nets based on the wiring information. ### Claim 7 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the circuit model conversion unit further comprises a net designation unit for designating the net to be used for executing the circuit simulation from among a plurality of nets when the nets are contained in the wiring information. ### Claim 8 (depends on 1) A circuit simulation model extracting device as defined in claim 1, further comprising: a net retrieval unit for retrieving a close net that is close to a designated net when a net has been designated by the net designation unit. ### Claim 9 (depends on 7) A circuit simulation model extracting device as defined in claim 7, further comprising: a net retrieval unit for retrieving an orthogonal net that is orthogonal to a designated net when a net has been designated by the net designation unit. ### Claim 10 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the circuit model conversion unit further comprises a receiver designation unit for designating the receiver to be used for executing the circuit simulation from among a plurality of receivers when the plurality of receivers are contained in the wiring information. ### Claim 11 (depends on 10) A circuit simulation model extracting device as defined in claim 10, further comprising: a net retrieval unit for retrieving a close net that is close to a designated receiver when a receiver has been designated by the receiver designation unit. ### Claim 12 (depends on 10) A circuit simulation model extracting device as defined in claim 10, further comprising: a net retrieval unit for retrieving an orthogonal net that is orthogonal to a designated receiver when a receiver has been designated by the receiver designation unit. ### Claim 13 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the circuit model conversion unit further comprises a direction conversion unit for converting a diagonal wiring into a wiring parallel to the horizontal direction in a cartesian coordinate system when the diagonal wiring is contained in the wiring information and the angle of the diagonal wiring with a prescribed line is equal to or less than a prescribed angle, and converting the diagonal wiring into a wiring parallel to the vertical direction when the angle exceeds the prescribed angle. ### Claim 14 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the line circuit converts a plurality of nets into the line subcircuit when the nets are contained in the wiring information and the distance between the nets is equal to or less than a prescribed distance, and converts none of the nets into the line subcircuit when the distance between the nets exceeds the prescribed distance. ### Claim 15 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the line circuit converts a plurality of parts of a plurality of nets into a line subcircuit when the plurality of nets are contained in the wiring information and the parts of the nets are close to each other and exceed a prescribed length, and converting none of the parts of the nets into a line subcircuit when the parts of the nets are equal to or less than the prescribed length. ### Claim 16 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the circuit model conversion unit further comprises an interlayer distance computation unit for computing a distance between the wiring of a self-layer and the wiring of another layer when the printed circuit board is a printed circuit board with a multilayer structure, and preparing a capacitive subcircuit according to the distance. ### Claim 17 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the circuit model conversion unit further comprises a junction-via processing unit for converting a junction via that connects the wiring of a self-layer with the wiring of another, adjacent layer into a capacitive subcircuit when the printed circuit board is a printed circuit board with a multilayer structure. ### Claim 18 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the circuit model conversion unit further comprises a compression circuit for compressing a first circuit and a second circuit connected to the first circuit into yet another single circuit when the first circuit, which is selected from among the power source circuit, the driver circuit, the line circuit, and the receiver circuit, is the same as the second circuit. ### Claim 19 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the circuit model conversion unit further comprises a resistance circuit for allocating a resistance subcircuit between the power source subcircuit and a pin subcircuit when a pin for inputting signals, the net connected to the pin, and the receiver connected to the net are contained in the wiring information. ### Claim 20 A circuit simulation model extracting method, comprising: a memory step for storing logic information expressing a plurality of logic function elements constituting a logic circuit, and wiring information about a plurality of components that correspond to the plurality of logic function elements on a printed circuit board, the wiring information for a plurality of printed circuit boards including a driver for performing driving based on signals from a power source, a receiver for receiving the signals, and a net for expressing wiring that interconnects the driver and the receiver; an extracting step for extracting the wiring information and logic information to be used for executing circuit simulation from among the wiring information and logic information stored in the memory step, the extracting step extracting from among the wiring information for the plurality of printed circuit boards stored in the memory step, the wiring information about the printed circuit boards that is to be used for executing the circuit simulation; a circuit model conversion step for converting the wiring information and logic information extracted by the extracting step into a circuit model suitable for executing the circuit simulation, the circuit model conversion step further comprising: a subcircuit storage step for storing as circuit simulation data, a power source subcircuit corresponding to the power source, a driver subcircuit corresponding to the driver, a receiver subcircuit corresponding to the receiver, and a line subcircuit corresponding to the net; a power source step for reading the power source subcircuit stored by a power source circuit in the subcircuit storage step; a driver step for converting the driver by means of a driver circuit into the driver subcircuit stored in the subcircuit storage step; a line step for converting the net by means of a line circuit into the line subcircuit stored in the subcircuit storage step; and a receiver step for converting the receiver by means of a receiver circuit into the receiver subcircuit stored in the subcircuit storage step; and a simulation step for executing the circuit simulation based on the circuit model converted in the circuit model conversion step, and identifying an electrical characteristic between the plurality of components that correspond to the wiring information and logic information extracted by the extracting step. ### Claim 21 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the extracting step extracts a plurality of nets from the wiring information when the nets are contained in the wiring information; and the line step converts a plurality of parts of the nets into a single line, and remaining parts of the nets into a plurality of lines when the parts of the nets extracted in the extracting step are close to each other. ### Claim 22 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the extracting step extracts a plurality of nets from the wiring information when the nets are contained in the wiring information; and the line step converts a plurality of parts of the nets as capacitors, and remaining parts of the nets into a plurality of lines when the parts of the nets extracted in the extracting step are orthogonal to each other. ### Claim 23 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the extracting step extracts a plurality of nets from the wiring information when the nets are contained in the wiring information, the circuit model conversion step converts the wiring information into the subcircuits for each of the plurality of nets. ### Claim 24 (depends on 21) A circuit simulation model extracting method as defined in claim 21, wherein the circuit model conversion step retrieves, for each net, a plurality of parts of the nets as close nets based on the wiring information. ### Claim 25 (depends on 22) A circuit simulation model extracting method as defined in claim 22, wherein the circuit model conversion step retrieves, for each net, a plurality of parts of the nets as orthogonal nets based on the wiring information. ### Claim 26 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the circuit model conversion step further comprises a net designation step for designating the net to be used for executing the circuit simulation from among a plurality of nets when the nets are contained in the wiring information. ### Claim 27 (depends on 26) A circuit simulation model extracting method as defined in claim 26, further comprising: a net retrieval step for retrieving a close net that is close to a designated net when this net has been designated in the net designation step. ### Claim 28 (depends on 26) A circuit simulation model extracting method as defined in claim 26, further comprising: a net retrieval step for retrieving an orthogonal net that is orthogonal to a designated net when a net has been designated in the net designation step. ### Claim 29 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the circuit model conversion step further comprises a receiver designation step for designating the receiver to be used for executing the circuit simulation from among a plurality of receivers when the plurality of receivers are contained in the wiring information. ### Claim 30 (depends on 29) A circuit simulation model extracting method as defined in claim 29, further comprising: a net retrieval step for retrieving a close net that is close to a designated receiver when a receiver has been designated in the receiver designation step. ### Claim 31 (depends on 29) A circuit simulation model extracting method as defined in claim 29, further comprising: a net retrieval step for retrieving an orthogonal net that is orthogonal to a designated receiver when a receiver has been designated in the receiver designation step. ### Claim 32 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the circuit model conversion step further comprises a direction conversion step for converting a diagonal wiring into a wiring parallel to the horizontal direction in a cartesian coordinate system when the diagonal wiring is contained in the wiring information and the angle of the diagonal wiring with a prescribed line is equal to or less than a prescribed angle, and converting the diagonal wiring into a wiring parallel to the vertical direction when the angle exceeds the prescribed angle. ### Claim 33 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the line step converts a plurality of nets into the line subcircuit when the nets are contained in the wiring information and the distance between the nets is equal to or less than a prescribed distance, and converts none of the nets into the line subcircuit when the distance between the nets exceeds the prescribed distance. ### Claim 34 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the line step converts a plurality of parts of a plurality of nets into a line subcircuit when the plurality of nets are contained in the wiring information and the parts of the nets are close to each other and exceed a prescribed length, and converting none of the parts of the nets into a line subcircuit when the parts of the nets are equal to or less than the prescribed length. ### Claim 35 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the circuit model conversion step further comprises an interlayer distance computation step for computing the distance between the wiring of a self-layer and the wiring of another layer when the printed circuit board is a printed circuit board with a multilayer structure, and preparing a capacitive subcircuit according to the distance. ### Claim 36 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the circuit model conversion step further comprises a junction-via processing step for converting a junction via that connects the wiring of a self-layer with the wiring of another, adjacent layer into a capacitive subcircuit when the printed circuit board is a printed circuit board with a multilayer structure. ### Claim 37 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the circuit model conversion step further comprises a compression step for compressing a first circuit and a second circuit connected to the first circuit into yet another single circuit when the first circuit, which is selected from among the power source circuit, the driver circuit, the line circuit, and the receiver circuit, is the same as the second circuit. ### Claim 38 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the circuit model conversion step further comprises a resistance generation step for allocating a resistance subcircuit between the power source subcircuit and a pin subcircuit when a pin for inputting signals, the net connected to the pin, and the receiver connected to the net are contained in the wiring information. ### Claim 39 (depends on 1) A circuit simulation model extracting device as defined in claim 1, comprising: a look-up table for storing electrical parameters corresponding to pieces of wiring information for the plurality of printed circuit boards, and the circuit model conversion unit for reading, from the look-up table, electrical parameters corresponding to the wiring information about printed circuit boards to be used for executing the circuit simulation, and adding the electrical parameters to the wiring information. ### Claim 40 (depends on 1) A circuit simulation model extracting device as defined in claim 1, wherein the circuit model conversion unit prepares a separate circuit model expressing the relation between a single target net and each influence net of one or more influence nets for each of the one or more influence nets when the single target net and the one or more influence nets are contained in the wiring information, and the single target net is a status of least one of close and orthogonal to the one or more influence nets; and the simulation unit executes the circuit simulation based on the separate circuit models prepared by the circuit model conversion unit for each the influence net, measures individual instances of a crosstalk noise, and combines the individual instances of crosstalk noise measured for each of the influence nets, computes the crosstalk noise which the single target net receives from the one or more influence nets. ### Claim 41 (depends on 20) A circuit simulation model extracting method as defined in claim 20, comprising: a preparation step for preparing a look-up table for storing electrical parameters corresponding to pieces of wiring information for the plurality of printed circuit boards; and the circuit model conversion step for reading, from the look-up table prepared in the preparation step, electrical parameters corresponding to the wiring information about printed circuit boards to be used for executing the circuit simulation, and adding the electrical parameters to the wiring information. ### Claim 42 (depends on 20) A circuit simulation model extracting method as defined in claim 20, wherein the circuit model conversion step prepares a separate circuit model expressing the relation between a single target net and each influence net of one or more influence nets for each of the one or more influence nets when the single target net and the one or more influence nets are contained in the wiring information, and the single target net is a status of least one of close and orthogonal to the one or more influence nets; and the simulation step executes the circuit simulation based on the separate circuit models prepared in the circuit model conversion step for each the influence net, measures individual instances of a crosstalk noise, and combines the individual instances of crosstalk noise measured for each of the influence nets, computes the crosstalk noise which the single target net receives from the one or more influence nets. ### Claim 43 A method of preparing a logic circuit model for a logic circuit to be designed and simulated by computer, comprising: constructing a first circuit model of said logic circuit by obtaining logic information for the logic circuit having a plurality of logic elements; obtaining wiring information from the logic circuit corresponding to logic elements placed on one or more printed circuit boards, the wiring information being modeled by logic elements, including a driver for performing driving based on signals from a power source, a receiver for receiving the signals, and a net for wiring that interconnects the driver and receiver; combining the logic information and the wiring information to form a first circuit model; forming a second circuit model by converting the wiring information into a form including electrical characteristics, including converting the driver into a driver subcircuit, the net into a line subcircuit, and the receiver into a receiver subcircuit, the driver, time and receiver subcircuit, and the receiver into a receiver subcircuit, such subcircuits identifying electrical characteristics in the second circuit model; simulating the second circuit model to determine circuit performance based on the electrical characteristics.