Apparatus and method for integrated circuit design with improved delay variation calculation based on power supply variations

• US 20080320427A1
• Filed: 06/20/2008
• Published: 12/25/2008
• Est. Priority Date: 06/21/2007
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Nakashima, Hidenari
• Granted Patent: US 8,056,033 B2
• Time in Patent Office: Days
• US Class Current: 716/113
• CPC Class Codes: G06F 2119/06 Power analysis or power optimisation
• CPC Class Codes: G06F 2119/12 Timing analysis or timing optimisation
• 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

An integrated circuit design apparatus is provided with a power supply voltage variation analysis tool calculating variations of power supply voltages of respective instances integrated within a target circuit; a determination module comparing the variations of the power supply voltages with first and second reference levels, the second reference level being smaller than the first reference level; a redesign module adapted to redesign the target circuit when at least one of the variations of the power supply voltages is larger than the first reference level; a delay variation calculation module adapted to correct circuit delay data of the respective instances based on the variations of the power supply voltages of the respective instances; a static timing analysis tool performing timing verification of the target integrated circuit. The timing verification in connection with each of the instances is performed based on the corrected circuit delay data, when a variation of a power supply voltage of the each of the instances is in a range from the second reference level to the first reference level, and performed based on the circuit delay data uncorrected, when the variation of the power supply voltage of the each of the instances is smaller than the second reference level.

Claims

1. An integrated circuit design apparatus comprising:

a power supply voltage variation analysis tool calculating variations of power supply voltages of respective instances integrated within a target circuit;

a determination module comparing said variations of said power supply voltages with first and second reference levels, said second reference level being smaller than said first reference level;

a redesign module adapted to redesign said target circuit when at least one of said variations of said power supply voltages is larger than said first reference level;

a delay variation calculation module adapted to correct circuit delay data of said respective instances based on said variations of said power supply voltages of said respective instances; and

a static timing analysis tool performing timing verification of said target integrated circuit,

wherein, in said timing verification, said corrected circuit delay data are used for a specific instance out of said instances within said target circuit, when a variation of a power supply voltage of said specific instance is in a range from said second reference level to said first reference level, and said circuit delay data uncorrected are used for said specific instance, when said variation of said power supply voltage of said specific instance is smaller than said second reference level.

2. The integrated circuit design apparatus according to claim 1, wherein said second reference level is dependent on a function of said target circuit.

3. The integrated circuit design apparatus according to claim 1, wherein a dynamic-noise dependent margin determined based on said variation of said power supply voltage of said specific instance is used for said timing verification of said specific instance, when said variation of said power supply voltage of said specific instance is in said range from said second reference level to said first reference level.

4. The integrated circuit design apparatus according to claim 3, wherein constant margin determined independently of said variation of said power supply voltage of said specific instance is used for said timing verification of said specific instance, when said variation of said power supply voltage of said specific instance is smaller than said second reference level.

5. The integrated circuit design apparatus according to claim 1, wherein said variations of power supply voltages of said respective instances are calculated by using a circuit operation pattern which allows said respective instances to operate at least once.

6. The integrated circuit design apparatus according to claim 1, wherein said circuit operation pattern is defined based on operation rates of said respective instances per clock cycle.

7. The integrated circuit design apparatus according to claim 1, further comprising a delay variation library describing associations of variations in power supply voltages with delay variations for respective kinds of instances and for respective possible input-pin states of said kinds of instances,

wherein said delay variation calculation tool are adapted to correct said circuit delay data by using said delay variation library.

8. The integrated circuit design apparatus according to claim 7, further comprising a delay variation library generator which generates said delay variation library, determining said associations of variations in power supply voltages with delay variations through circuit simulation.

9. The integrated circuit design apparatus according to claim 8, wherein said power supply voltage variation analysis tool further calculates variations in power supply currents of said respective instances based on said variations in power supply voltages of said respective instances, and

wherein said delay variation calculation tool are adapted to correct said circuit delay data of respective instances based on said variations in said power supply currents in addition to said variations in said power supply voltages.

10. A computer-readable recording medium which records a program that when executed controls a computer to perform a method comprising:

calculating variations of power supply voltages of respective instances integrated within a target circuit;

comparing said variations of said power supply voltages with first and second reference levels, said second reference level being smaller than said first reference level;

redesigning said target circuit when at least one of said variations of said power supply voltages is larger than said first reference level;

correcting circuit delay data of each of said respective instances based on a variation of a power supply voltage of said each of said respective instances, when said variation of said power supply voltage of said each of said instances is in a range from said second reference level to said first reference level; and

performing timing verification of said target circuit,

wherein, in said timing verification, said corrected circuit delay data are used for a specific instance out of said instances within said target circuit, when a variation of a power supply voltage of said specific instance is in a range from said second reference level to said first reference level, and said circuit delay data uncorrected are used for said specific instance, when said variation of said power supply voltage of said specific instance is smaller than said second reference level.

11. The computer-readable recording medium according to claim 10, wherein said second reference level is dependent on a function of said target circuit.

12. The computer-readable recording medium according to claim 10, wherein a dynamic-noise dependent margin determined based on said variation of said power supply voltage of said specific instance is used for said timing verification of said specific instance, when said variation of said power supply voltage of said specific instance is in said range from said second reference level to said first reference level.

13. The computer-readable recording medium according to claim 12, wherein a constant margin determined independently of said variation of said power supply voltage of said specific instance is used for said timing verification of said specific instance, when said variation of said power supply voltage of said specific instance is smaller than said second reference level.

14. The computer-readable recording medium according to claim 10, wherein said variations of power supply voltages of said respective instances are calculated by using a circuit operation pattern which allows said respective instances to operate at least once.

15. An integrated circuit design method comprising:

calculating variations of power supply voltages of respective instances integrated within a target circuit;

comparing said variations of said power supply voltages with first and second reference levels, said second reference level being smaller than said first reference level;

redesigning said target circuit when at least one of said variations of said power supply voltages is larger than said first reference level;

correcting circuit delay data of each of said respective instances based on a variation of a power supply voltage of said each of said respective instances, when said variation of said power supply voltage of said each of said instances is in a range from said second reference level to said first reference level; and

performing timing verification of said target circuit,

wherein, in said timing verification, said corrected circuit delay data are used for a specific instance out of said instances within said target circuit, when a variation of a power supply voltage of said specific instance is in a range from said second reference level to said first reference level, and said circuit delay data uncorrected are used for said specific instance, when said variation of said power supply voltage of said specific instance is smaller than said second reference level.

16. The integrated circuit design method according to claim 15, wherein said second reference level is dependent on a function of said target circuit.

17. The integrated circuit design method according to claim 15, wherein a dynamic-noise dependent margins determined based on said variation of said power supply voltage of said specific instance is used for said timing verification of said specific instance, when said variation of said power supply voltage of said specific instance is in said range from said second reference level to said first reference level.

18. The integrated circuit design method according to claim 17, wherein a constant margin determined independently of said variation of said power supply voltage of said specific instance is used for said timing verification of said specific instance, when said variation of said power supply voltage of said specific instance is smaller than said second reference level.

19. The integrated circuit design method according to claim 15, wherein said variations of power supply voltages of said respective instances are calculated by using a circuit operation pattern which allows said respective instances to operate at least once.