US 8,015,526 B2Granted

Static timing slacks analysis and modification

AssigneeInternational Business Machines Corporation

InventorsThomas B. Chadwick, Jr., Margaret R. Charlebois, David J. Hathaway, Jason E. Rotella, Douglas W. Stout, Ivan L. Wemple

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Abstract

A method, system and computer program product for analyzing and modifying a static timing slack of a timing path in a static timing analysis of a design of an integrated circuit (IC) with a transient power supply are disclosed. A static timing slack analysis is performed at a selected endpoint in an IC to obtain a candidate timing path leading to the endpoint with a worst static timing slack. A transient static timing slack is determined for the candidate timing path for each clock cycle of a clock signal under the transient power supply. The determined transient static timing slack is used to adjust the timing of the IC and to modify the static timing slack of the candidate timing path.

Claims17

Dependent claims

A method for analyzing and modifying a static timing slack of a timing path in a static timing analysis of a design of an integrated circuit (IC) with a transient power supply, the method comprising steps of:

constructing a timing model of an IC based on an upper end voltage supply and a lower end voltage supply using a computer;
selecting an endpoint in the IC to perform a static timing slack analysis on the endpoint based on the upper end voltage supply and the lower end voltage supply;
selecting a candidate timing path with a bounded static timing slack of a minimum value among all timing paths leading to the selected endpoint based on the static timing slack analysis;
determining a transient static timing slack of the candidate timing path based on the transient power supply using a computer;
and
modifying the bounded static timing slack of the candidate timing path based on the transient static timing slack using a computer wherein the transient static timing slack includes calculating a late mode delay of a first signal in an element in a second path leading to the endpoint based on the transient power supply, and the late mode delay calculating includes;
determining a late mode arrival time for the first signal to arrive at an input of the element;
determining a voltage value of the transient power supply on the element at the late mode arrival time;
calculating an interim late mode delay based on the voltage value on the element at the late arrival time;
determining a minimum voltage value of the transient power supply on the element within a time period of the interim late mode delay;
and
calculating the late mode delay based on the determined minimum voltage value.

9 more elements

A system for analyzing and modifying a static timing slack of a timing path in a static timing analysis of a design of an integrated circuit (IC) with a transient power supply, the system comprising:

at least one computing device configured to analyze and modify a static timing slack of a timing path in a static timing analysis of a design of an integrated circuit with a transient power supply by performing a method including;
selecting an upper end voltage supply and a lower end voltage supply to be used in constructing a timing model of an IC;
selecting an endpoint in the IC to perform a static timing slack analysis on the endpoint based on the upper end voltage supply and the lower end voltage supply;
selecting a candidate timing path with a bounded static timing slack of a minimum value among all timing paths leading to the selected endpoint based on the static timing slack analysis;
determining a transient static timing slack of the candidate timing path based on the transient power supply;
and
modifying the bounded static timing slack of the candidate timing path based on the transient static timing slack, wherein the transient static timing slack includes calculating a late mode delay of a first signal in an element in a second path leading to the endpoint based on the transient power supply, and the late mode delay calculating includes;
determining a late mode arrival time for the first signal to arrive at an input of the element;
determining a voltage value of the transient power supply on the element at the late mode arrival time;
calculating an interim late mode delay based on the voltage value on the element at the late arrival time;
determining a minimum voltage value of the transient power supply on the element within a time period of the interim late mode delay;
and
calculating the late mode delay based on the determined minimum voltage value.

10 more elements

A non-transitory computer readable medium comprising a computer program product stored thereon, which when executed, enables a computer system to execute a method for analyzing and modifying a static timing slack of a timing path in a static timing analysis of a design of an integrated circuit (IC) with a transient power supply, the method comprising:

selecting an upper end voltage supply and a lower end voltage supply to be used in constructing a timing model of an IC;
selecting an endpoint in the IC to perform a static timing slack analysis on the endpoint based on the upper end voltage supply and the lower end voltage supply;
selecting a candidate timing path with a bounded static timing slack of a minimum value among all timing paths leading to the selected endpoint based on the static timing slack analysis;
determining a transient static timing slack of the candidate timing path based on the transient power supply;
and
modifying the bounded static timing slack of the candidate timing path based on the transient static timing slack, wherein the transient static timing slack includes calculating a late mode delay of a first signal in an element in a second path leading to the endpoint based on the transient power supply, and the late mode delay calculating includes;
determining a late mode arrival time for the first signal to arrive at an input of the element;
determining a voltage value of the transient power supply on the element at the late mode arrival time;
calculating an interim late mode delay based on the voltage value on the element at the late arrival time;
determining a minimum voltage value of the transient power supply on the element within a time period of the interim late mode delay;
and
calculating the late mode delay based on the determined minimum voltage value.

9 more elements

Dependencies are inferred from the claim text.