Emulation of power shutoff behavior for integrated circuits

• US 8,812,286 B1
• Filed: 01/08/2013
• Issued: 08/19/2014
• Est. Priority Date: 10/31/2007
• Status: Active Grant

• Current Assignee: Cadence Design Systems Incorporated (Cadence Group)
• Original Assignee: Cadence Design Systems Incorporated (Cadence Group)
• Inventors: Lin, Tsair-Chin, Zhu, Bing, Beletsky, Platon
• Primary Examiner(s): Shah, Kamini S
• Assistant Examiner(s): Chad, Aniss
• Application Number:
  US13/736,583
• Time in Patent Office: 588 Days
• Field of Search: 703/14, 703/18, 703/23, 703/28, 716/133
• US Class Current: 703/18
• CPC Class Codes: G06F 2119/06 Power analysis or power optimisation
• CPC Class Codes: G06F 30/33 Design verification, e.g. functional simulation or model checking
• 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

A method for modeling power management in an integrated circuit (IC) includes: specifying a circuit design and a power architecture for the IC, the power architecture including a plurality of power domains for specifying power levels in different portions of the IC; determining an emulation module for the IC by including one or more hardware elements for modeling the power architecture in the emulation module; and using the emulation module to simulate changing power levels in one or more power domains of the IC including a power shutoff in at least one power domain.

Claims

1. A method for modeling power management in an integrated circuit (IC) comprising:

specifying a circuit design and a power architecture for the IC, the circuit design including a plurality of circuit elements included in the IC, and the power architecture including a plurality of power domains for specifying power levels in different portions of the IC;

determining an emulation module for the IC by including one or more hardware elements for modeling the power architecture in the emulation module, the one or more hardware elements including a first hardware element that receives a signal-value input for a first circuit element of a first power domain of the IC and provides a signal-value output that corresponds to an output of the first circuit element, the first hardware element further receiving a power-shutoff control input for changing power levels in the first power domain between a power-on configuration and a power-off configuration, and the first hardware element further receiving a state-retention control input for saving a state-retention value corresponding to the signal-value output in the power-off configuration; and

using the emulation module to simulate changing power levels in one or more power domains of the IC including a power shutoff in the first power domain, the first hardware element providing the signal-value input as the signal-value output in the power-on configuration, providing a power-shutoff value as the signal-value output in the power-off configuration, and in a switching operation from the power-off configuration to the power-on configuration providing the state-retention value as a restored value to the signal-value output before the signal-value input is provided as the signal-value output.

2. The method of claim 1, wherein the first hardware element includes a logic gate that receives the power-shutoff control input for changing the power levels in the first power domain in combination with an input corresponding to the signal-value input or the state-retention value.

3. The method of claim 1, wherein the emulation module includes at least one hardware element that receives an isolation control input for modeling cell isolation in the power-off configuration by blocking an isolated signal from a portion of the IC.

4. The method of claim 1, further comprising:

using a random-number generator to randomize the power-shutoff value.

5. The method of claim 1, wherein determining the emulation module includes:

using a random-number generator to determine a randomizing value; and

using the randomizing value to select a power-switch hardware element that receives a power switch input for power switching and provides one or more values that are correspondingly randomized for the power-shutoff value when using the emulation module.

6. The method of claim 1, wherein determining the emulation module includes:

using a random-number generator to determining a randomizing input; and

selecting a multiplexer that receives the randomizing input and provides correspondingly randomized values for the power-shutoff value when using the emulation module.

7. The method of claim 1, wherein determining the emulation module includes:

selecting a control element that receives power-switch signals for the power domains and adjusts values for the first hardware element in a power-loss state when using the emulation module.

8. The method of claim 1, further comprising:

saving one or more values for the simulated power levels of the IC.

9. The method of claim 1, further comprising:

saving into a database selected values for IC primary inputs, IC primary outputs and sequential element outputs from using the emulation module; and

using at least some values from the database to calculate power-management characteristics for a selected power domain.

10. The method of claim 1, further comprising:

associating emulation-module values with the power domains;

calculating power-mode values for the simulated changing power levels of the IC from the emulation-values; and

displaying the power mode values for the IC.

11. An apparatus for modeling power management in an integrated circuit (IC), the apparatus comprising a computer for executing computer instructions, wherein the computer includes computer instructions for:

specifying a circuit design and a power architecture for the IC, the circuit design including a plurality of circuit elements included in the IC, and the power architecture including a plurality of power domains for specifying power levels in different portions of the IC;

determining an emulation module for the IC by including one or more hardware elements for modeling the power architecture in the emulation module, the one or more hardware elements including a first hardware element that receives a signal-value input for a first circuit element of a first power domain of the IC and provides a signal-value output that corresponds to an output of the first circuit element, the first hardware element further receiving a power-shutoff control input for changing power levels in the first power domain between a power-on configuration and a power-off configuration, and the first hardware element further receiving a state-retention control input for saving a state-retention value corresponding to the signal-value output in the power-off configuration; and

using the emulation module to simulate changing power levels in one or more power domains of the IC including a power shutoff in the first power domain, the first hardware element providing the signal-value input as the signal-value output in the power-on configuration, providing a power-shutoff value as the signal-value output in the power-off configuration, and in a switching operation from the power-off configuration to the power-on configuration providing the state-retention value as a restored value to the signal-value output before the signal-value input is provided as the signal-value output.

12. The apparatus of claim 11, wherein the first hardware element includes a logic gate that receives the power-shutoff control input for changing the power levels in the first power domain in combination with an input corresponding to the signal-value input or the state-retention value.

13. The apparatus of claim 11, wherein the computer further includes computer instructions for:

using a random-number generator to randomize the power-shutoff value.

14. The apparatus of claim 11, wherein determining the emulation module includes:

using a random-number generator to determine a randomizing value; and

using the randomizing value to select a power-switch hardware element that receives a power-switch input for switching power and provides one or more values that are correspondingly randomized for the power-shutoff value when using the emulation module.

15. The apparatus of claim 11, wherein determining the emulation module includes:

using a random-number generator to determine a randomizing input; and

selecting a multiplexer that receives the randomizing input and provides correspondingly randomized values for the power-shutoff value when using the emulation module.

16. The apparatus of claim 11, wherein determining the emulation module includes:

selecting a control element that receives power-switch signals for the power domains and adjusts values for the first hardware element in a power-loss state when using the emulation module.

17. A non-transitory computer-readable medium that stores a computer program for modeling power management in an integrated circuit (IC), wherein the computer program includes instructions for:

specifying a circuit design and a power architecture for the IC, the circuit design including a plurality of circuit elements included in the IC, and the power architecture including a plurality of power domains for specifying power levels in different portions of the IC;

determining an emulation module for the IC by including one or more hardware elements for modeling the power architecture in the emulation module, the one or more hardware elements including a first hardware element that receives a signal-value input for a first circuit element of a first power domain of the IC and provides a signal-value output that corresponds to an output of the first circuit element, the first hardware element further receiving a power-shutoff control input for changing power levels in the first power domain between a power-on configuration and a power-off configuration, and the first hardware element further receiving a state-retention control input for saving a state-retention value corresponding to the signal-value output in the power-off configuration; and

using the emulation module to simulate changing power levels in one or more power domains of the IC including a power shutoff in the first power domain, the first hardware element providing the signal-value input as the signal-value output in the power-on configuration, providing a power-shutoff value as the signal-value output in the power-off configuration, and in a switching operation from the power-off configuration to the power-on configuration providing the state-retention value as a restored value to the signal-value output before the signal-value input is provided as the signal-value output.

18. The non-transitory computer-readable medium of claim 17, wherein the first hardware element includes a logic gate that receives the power-shutoff control input for changing the power levels in the first power domain in combination with an input corresponding to the signal-value input or the state-retention value.

19. The non-transitory computer-readable medium of claim 17, wherein the computer program further includes instructions for:

using a random-number generator to randomize the power-shutoff value.

20. The non-transitory computer-readable medium of claim 17, wherein determining the emulation module includes:

using a random-number generator to determine a randomizing value; and

using the randomizing value to select a power-switch hardware element that receives a power-switch input for switching power and provides one or more values that are correspondingly randomized for the power-shutoff value when using the emulation module.

21. The non-transitory computer-readable medium of claim 17, wherein determining the emulation module includes:

using a random-number generator to determine a randomizing input; and

selecting a multiplexer that receives the randomizing input and provides correspondingly randomized values for the power-shutoff value when using the emulation module.

22. The non-transitory computer-readable medium of claim 17, wherein determining the emulation module includes:

selecting a control element that receives power-switch signals for the power domains and adjusts values for the first hardware element in a power-loss state when using the emulation module.