SIMULATION METHOD AND SIMULATION PROGRAM

• US 20070186194A1
• Filed: 01/04/2007
• Published: 08/09/2007
• Est. Priority Date: 02/09/2006
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Sato, Junji, Lee, Peter Maurice, Yokomizo, Goichi
• Granted Patent: US 7,721,234 B2
• Time in Patent Office: Days
• US Class Current: 716/111
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods

Abstract

There is a need for keeping the amount of data to be saved and a simulation process time almost constant irrespectively of a hierarchical level of a hierarchical circuit to be simulated. This simulation method includes a first process and a second process. The first process saves result data obtained from simulating an interface node between higher-level and lower-level hierarchies in accordance with a result of simulation using hierarchical circuit data hierarchized for multiple hierarchies. The second process uses result data saved by the first process to reproduce internal node data not saved by the first process. Result data for the interface node between hierarchies indirectly determines a value for the internal node. Result data to be saved is data concerning the interface node between hierarchies. The amount of saved data and the time needed for the second process are independent of a hierarchical level or a higher-level or lower-level hierarchy.

Claims

1. A simulation method comprising:

a first process for saving result data obtained from simulating an interface node between higher-level and lower-level hierarchies in accordance with a result of simulation using hierarchical circuit data hierarchized for a plurality of hierarchies; and

a second process for using result data saved by the first process to reproduce internal node data not saved by the first process.

2. The simulation method according to claim 1, wherein a simulation in the second process is performed using a same initial condition as for a simulation in the first process.

3. The simulation method according to claim 2,

wherein the first process also saves simulation result data of an internal node different from an interface node between higher-level and lower-level hierarchies when the simulation result data determines a value of a voltage source or a current source in another hierarchy.

4. The simulation method according to claim 1,

wherein a hierarchical circuit having an internal node as an object of the second process has a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is connected to a ground potential, and

wherein the second process then supplies electric current information as input/output information to the specific node.

5. The simulation method according to claim 1,

wherein a hierarchical circuit having an internal node as an object of the second process has a partial circuit including one voltage source or at least two connected voltage sources, one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is connected to a ground potential, and

wherein the second process then supplies electric current information as input/output information to the specific node.

6. The simulation method according to claim 1,

wherein a hierarchical circuit having an internal node as an object of the second process has a partial circuit including one voltage source or two or more connected voltage sources, one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is connected to a ground potential,

wherein the second process ignores electric current flowing through voltage sources of the partial circuit, and

wherein all the specific nodes are then floated.

7. The simulation method according to claim 1,

wherein a hierarchical circuit having an internal node as an object of the second process has a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is connected to a ground potential,

wherein the second process ignores electric current flowing through all elements of the partial circuit, and

wherein the partial circuit is then deleted.

8. The simulation method according to claim 1,

wherein a hierarchical circuit having an internal node as an object of the second process has a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is not connected to a ground potential, and

wherein the second process then supplies voltage source information as input/output information to one of the two or more specific nodes and supplies current source information as input/output information to the remaining specific nodes.

9. The simulation method according to claim 1,

wherein a hierarchical circuit having an internal node as an object of the second process has a partial circuit including one voltage source or at least two connected voltage sources, two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is not connected to a ground potential, and

wherein the second process then supplies voltage source information as input/output information to one of the two or more specific nodes and supplies current source information as input/output information to the remaining specific nodes.

10. The simulation method according to claim 1,

wherein a hierarchical circuit having an internal node as an object of the second process has a partial circuit including one voltage source or two or more connected voltage sources, two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is not connected to a ground potential,

wherein the second process ignores electric current flowing through voltage sources of the partial circuit, and

wherein the second process then supplies voltage source information as input/output information to one specific node and floats the remaining specific nodes.

11. The simulation method according to claim 1,

wherein a hierarchical circuit having an internal node as an object of the second process has a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is not connected to a ground potential,

wherein the second process ignores electric current flowing through all elements of the partial circuit, and

wherein the partial circuit is then deleted.

12. A simulation method comprising:

an extraction process for extracting a circuit node in a specified hierarchy from hierarchical circuit data;

a simulation execution process for executing a circuit simulation using a circuit node extracted by the extraction process as a result output node;

a save process for saving result data that is obtained by the simulation execution process for a result output node and relates to an interface node between higher-level and lower-level hierarchies; and

a simulation re-execution process for using the saved result data concerning an interface node between a specified hierarchy and a hierarchy one level higher or lower and obtaining simulation result data for a circuit node in the specified hierarchy.

13. The simulation method according to claim 12,

wherein the save process saves simulation result data for an internal node different from an interface node between higher-level and lower-level hierarchies when the simulation result data determines a value for a voltage source or current source in another hierarchy, and

wherein the save process saves simulation result data for an element in the hierarchy when the simulation result data determines a value for a voltage source or current source in another hierarchy.

14. The simulation method according to claim 13,

wherein the simulation re-execution process performs a simulation under a same initial condition as for a simulation by the simulation execution process.

15. The simulation method according to claim 14, further comprising:

a display process for displaying result data saved by the save process in response to an instruction to display a simulation result or displaying a simulation result obtained by the simulation re-execution process.

16. The simulation method according to claim 15,

wherein the extraction process registers a circuit node identifiable at a specified hierarchical level each time the extraction process changes a hierarchical level to a lower one while keeping track of a series of reference to a lower-level hierarchy in hierarchical circuit data, and

wherein this process is performed for all series of reference in an object under simulation.

24. The simulation method according to claim 12,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be connected to a ground potential, and

wherein the second process then supplies electric current information as input/output information to the specific node.

25. The simulation method according to claim 12,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or at least two connected voltage sources, one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be connected to a ground potential, and

wherein the second process then supplies electric current information as input/output information to the specific node.

26. The simulation method according to claim 12,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or two or more connected voltage sources, one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through a voltage source of the partial circuit, and

wherein all the specific nodes are then floated.

27. The simulation method according to claim 12,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through all elements of the partial circuit, and

wherein the partial circuit is then deleted.

28. The simulation method according to claim 12,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be not connected to a ground potential, and

wherein the second process then supplies voltage source information as input/output information to one of the two or more specific nodes and supplies current source information as input/output information to the remaining specific nodes.

29. The simulation method according to claim 12,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or at least two connected voltage sources, two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be not connected to a ground potential, and

wherein the second process then supplies voltage source information as input/output information to one of the two or more specific nodes and supplies current source information as input/output information to the remaining specific nodes.

30. The simulation method according to claim 12,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or two or more connected voltage sources, two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be not connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through a voltage source of the partial circuit, and

wherein the second process then supplies voltage source information as input/output information to one specific node and floats the remaining specific nodes.

31. The simulation method according to claim 12, 17, or 20,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be not connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through all elements of the partial circuit, and

wherein the partial circuit is then deleted.

17. A simulation method comprising:

a simulation execution process for performing a circuit simulation using a circuit node for a hierarchical circuit data in a specified hierarchy as a result output node;

a save process for saving result data that is obtained by the simulation execution process for a result output node and relates to an interface node between higher-level and lower-level hierarchies;

a first display process for displaying result data retrieved from those saved by the save process as a result of the simulation execution process;

a simulation re-execution process for using the saved result data concerning an interface node between a specified hierarchy and a hierarchy one level higher or lower and obtaining simulation result data for a circuit node in the specified hierarchy; and

a second display process for displaying result data from the simulation re-execution process.

18. The simulation method according to claim 17,

wherein the save process saves simulation result data for an internal node different from an interface node between higher-level and lower-level hierarchies when the simulation result data determines a value for a voltage source or current source in another hierarchy, and

wherein the save process saves simulation result data for an element in the hierarchy when the simulation result data determines a value for a voltage source or current source in another hierarchy.

19. The simulation method according to claim 18,

wherein the simulation re-execution process performs a simulation under an initial condition equivalent to that for a simulation by the simulation execution process.

36. The simulation method according to claim 17,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be connected to a ground potential, and

wherein the second process then supplies electric current information as input/output information to the specific node.

38. The simulation method according to claim 17,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or at least two connected voltage sources, one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be connected to a ground potential, and

wherein the second process then supplies electric current information as input/output information to the specific node.

40. The simulation method according to claim 17,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or two or more connected voltage sources, one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through a voltage source of the partial circuit, and

wherein all the specific nodes are then floated.

42. The simulation method according to claim 17,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through all elements of the partial circuit, and

wherein the partial circuit is then deleted.

44. The simulation method according to claim 17,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be not connected to a ground potential, and

wherein the second process then supplies voltage source information as input/output information to one of the two or more specific nodes and supplies current source information as input/output information to the remaining specific nodes.

46. The simulation method according to claim 17,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or at least two connected voltage sources, two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be not connected to a ground potential, and

wherein the second process then supplies voltage source information as input/output information to one of the two or more specific nodes and supplies current source information as input/output information to the remaining specific nodes.

48. The simulation method according to claim 17,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or two or more connected voltage sources, two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be not connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through a voltage source of the partial circuit, and

wherein the second process then supplies voltage source information as input/output information to one specific node and floats the remaining specific nodes.

50. The simulation method according to claim 17,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be not connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through all elements of the partial circuit, and

wherein the partial circuit is then deleted.

20. A simulation method comprising:

a simulation execution process for performing a circuit simulation using a circuit node for a hierarchical circuit data in a specified hierarchy as a result output node;

a save process for saving result data that is obtained by the simulation execution process for a result output node and relates to an interface node between higher-level and lower-level hierarchies; and

a simulation re-execution process for performing a circuit simulation for a circuit node reflecting modification of the hierarchical circuit data, when modified, using the saved result data concerning an interface node between the circuit node and an interfaced hierarchy one level higher or lower.

21. The simulation method according to claim 20,

wherein the simulation re-execution process parallel performs a circuit simulation for the modification reflecting circuit nodes whose signal paths are independent of each other.

37. The simulation method according to claim 20,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be connected to a ground potential, and

wherein the second process then supplies electric current information as input/output information to the specific node.

39. The simulation method according to claim 20,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or at least two connected voltage sources, one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be connected to a ground potential, and

wherein the second process then supplies electric current information as input/output information to the specific node.

41. The simulation method according to claim 20,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or two or more connected voltage sources, one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through a voltage source of the partial circuit, and

wherein all the specific nodes are then floated.

43. The simulation method according to claim 20,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through all elements of the partial circuit, and

wherein the partial circuit is then deleted.

45. The simulation method according to claim 20,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be not connected to a ground potential, and

wherein the second process then supplies voltage source information as input/output information to one of the two or more specific nodes and supplies current source information as input/output information to the remaining specific nodes.

47. The simulation method according to claim 20,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or at least two connected voltage sources, two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be not connected to a ground potential, and

wherein the second process then supplies voltage source information as input/output information to one of the two or more specific nodes and supplies current source information as input/output information to the remaining specific nodes.

49. The simulation method according to claim 20,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one voltage source or two or more connected voltage sources, two or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy, and another circuit for connection to the partial circuit,

wherein the partial circuit is supposed to be not connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through a voltage source of the partial circuit, and

wherein the second process then supplies voltage source information as input/output information to one specific node and floats the remaining specific nodes.

51. The simulation method according to claim 20,

wherein a hierarchical circuit having an internal node as an object of the second process is supposed to have a partial circuit including one of elements such as a voltage source and an inductor or at least two connected elements such as a voltage source and an inductor and have one or more specific nodes for connecting the partial circuit to a hierarchical circuit in another hierarchy,

wherein the partial circuit is supposed to be not connected to a ground potential,

wherein the second process is supposed to ignore an electric current flowing through all elements of the partial circuit, and

wherein the partial circuit is then deleted.

22. A simulation method comprising:

a first process for extracting a result output point in a specified higher-level hierarchy from an object under simulation;

a second process for simulating an extracted result output point;

a third process for saving result data that is obtained by the simulation execution process for a result output node and relates to an interface node between higher-level and lower-level hierarchies; and

a fourth process for using the saved result data concerning an interface node between a specified hierarchy and a hierarchy one level higher or lower and simulating a circuit node in the specified hierarchy so as to obtain simulation result data under an initial condition equivalent to that for a simulation by the second process.

23. The simulation method according to claim 22,

wherein the save process saves simulation result data for an internal node different from an interface node between higher-level and lower-level hierarchies when the simulation result data determines a value for a voltage source or current source in another hierarchy, and

wherein the save process saves simulation result data for an element in the hierarchy when the simulation result data determines a value for a voltage source or current source in another hierarchy.

32. A simulation program executed by a computer so as to perform a data process for supporting circuit simulation, the data process comprising:

a first process for saving simulation result data concerning an interface node between higher-level and lower-level hierarchies out of a result of simulation using hierarchical circuit data hierarchized for a plurality of hierarchies; and

a second process for using result data saved by the first process to reproduce internal node data not saved by the first process.

33. A simulation program executed by a computer so as to perform a data process for supporting circuit simulation, the data process comprising:

an extraction process for extracting a circuit node in a specified hierarchy from hierarchical circuit data;

a simulation execution process for executing a circuit simulation using a circuit node extracted by the extraction process as a result output node;

a save process for saving result data that relates to an interface node between higher-level and lower-level hierarchies and is obtained by the simulation execution process for a result output node; and

a simulation re-execution process for using the saved result data concerning an interface node between a specified hierarchy and a hierarchy one level higher or lower and obtaining simulation result data for a circuit node in the specified hierarchy.

34. A simulation program executed by a computer so as to perform a data process for supporting circuit simulation, the data process comprising:

a simulation execution process for performing a circuit simulation using a circuit node for a hierarchical circuit data in a specified hierarchy as a result output node;

a save process for saving result data that relates to an interface node between higher-level and lower-level hierarchies and is obtained by the simulation execution process for a result output node;

a first display process for displaying result data retrieved from those saved by the save process as a result of the simulation execution process;

a simulation re-execution process for using the saved result data concerning an interface node between a specified hierarchy and a hierarchy one level higher or lower and obtaining simulation result data for a circuit node in the specified hierarchy; and

a second display process for displaying result data from the simulation re-execution process.

35. A simulation program executed by a computer so as to perform a data process for supporting circuit simulation, the data process comprising:

a first process for extracting a result output point in a specified higher-level hierarchy from an object under simulation;

a second process for simulating an extracted result output point;

a third process for saving result data that relates to an interface node between higher-level and lower-level hierarchies and is obtained by the simulation execution process for a result output node; and

a fourth process for using the saved result data concerning an interface node between a specified hierarchy and a hierarchy one level higher or lower and simulating a circuit node in the specified hierarchy so as to obtain simulation result data under an initial condition equivalent to that for a simulation by the second process.