Synopsys, Inc.

Synplicity, Inc.

Khalid Rahmat

Kenneth S McElvain

Kayhan Kucukcakar

Sarvesh Bhardwaj

Rachid Helaihel

Feroze P Taraporevala

William Chiu-Ting Shu

Jindrich Zejda

Cristian Soviani

Ming Huei Young

Methods and apparatuses for circuit design to reduce power usage, such as reducing temperature dependent power usage, and/or to improve timing, such as reducing temperature dependent delay or transition time. At least one embodiment of the method implemented on a data processing system for circuit design, the method comprises determining for a first design of a circuit a first temperature solution and a first power dissipation solution, the first power dissipation solution and the first temperature solution being interdependent, and transforming the first design of the circuit into a second design of the circuit using the first temperature solution to reduce leakage power of the circuit under one or more design constraints.

Thermal analysis based circuit design

A system and a method are disclosed for performing clock re-convergence pessimism removal (CRPR) during hierarchical static timing analysis (HSTA). A clock network is divided into a plurality of blocks. A top level includes clock components not included in the plurality of blocks. Block level analysis is performed to determine timing information for each of the plurality of blocks. If available, CRPR data from top level analysis is accounted for in block level analysis. Subsequently, similar analysis is performed on components that are included in top level analysis. If available, CRPR data from bottom level analysis is accounted for in top level analysis. CRPR data can be requested during levels of analysis from the other level. These steps are repeated until analysis is complete.

Clock-reconvergence pessimism removal in hierarchical static timing analysis

A system and a method are disclosed for reducing memory used in storing totals during static timing analysis. Totals are stored at various points along paths analyzed in static timing analysis. Some totals may not be merged for reasons including differing clock re-convergence pessimism removal (CRPR) dominators, exceptions, or clocks. Totals at a point may be stored in a super-tag mapping table and replaced at the point with a super-tag. The super-tag includes a super-tag ID referencing the totals stored in the super-tag mapping table. The super-tag also includes a time delay value. The time delay value allows the super-tag ID to be reused in other super-tags at other points while still storing total time delays at the other points. Therefore, the memory used to store totals is reduced in many situations.

Reducing memory used to store totals in static timing analysis

Methods and apparatuses for circuit design to reduce power usage, such as reducing temperature dependent power usage, and/or to improve timing, such as reducing temperature dependent delay or transition time. At least one embodiment of the present invention reduces the power dissipation and improves the timing of an integrated circuit to optimize the design. A thermal analysis is used to determine the temperature dependent power dissipation of a circuit and the temperature distribution of the circuit resulting from dissipating the heat created by the temperature dependent power dissipation. Then, the components of the design are selectively transformed to reduce the power dissipation and to improve timing based on the temperature solution. The transformation may include placement changes and netlist changes, such as the change of transistor threshold voltages for cells or for blocks of the circuit chip.

Embodiments of a computer system, a method, an integrated circuit and a computer-program product (i.e., software) for use with the computer system are described. These devices and techniques may be used to perform STA for circuits that include multiple power domains. Power-domain crossing information and optionally the delay in each power domain can be propagated during the full circuit graph-based STA to accurately perform STA without enumerating all paths. Some embodiments can use a tag-based engine to track power-domain crossing(s) during graph-based STA. If a power-domain is crossed in a path, pessimism may be added to the cumulative delay at the end point of the path. For those paths that do not cross a power domain, pessimism may be removed from the cumulative delay at their end points. In some embodiments, pessimism may be removed from the cumulative delay at end points for paths that cross power domains.

Multiple-power-domain static timing analysis

One embodiment of the present invention provides a system that performs an efficient path-based static timing analysis (STA) in a circuit design. During operation, the system identifies a set of paths within the circuit design, wherein each path includes one or more segments. For a path in the set of paths, the system determines if at least one segment in the path is shared with a different path which was previously computed by performing a path-based STA, wherein the at least one segment in the different path is associated with previously computed path-based timing information. If so, the system then performs an estimation of a path-based delay for the path based at least on the path-based timing information associated with the shared segment in the different path. Otherwise, the system computes a path-based delay for the path by performing a path-based STA on the path.

Efficient exhaustive path-based static timing analysis using a fast estimation technique

Methods and apparatuses for transient simulation of circuits. One embodiment of the present invention eliminates the inductive branch current variables in terms of node voltage variables to generate a linear equation system with a sparse, symmetric and positive definite matrix, which can be solved efficiently using a pre-conditioned conjugate gradient method. The known vector of the linear equation system includes the contribution from the known inductive branch currents at a previous time instance. In one embodiment of the present invention, a node on a branch to a known voltage, such as ground, and on two resistive branches are identified and eliminated to form the linear equation system with a reduced dimension. In one embodiment of the present invention, multiple time step sizes are selectively used to balance the accuracy in transient simulation and efficiency.

Methods and apparatuses for circuit simulation

Methods and apparatuses for thermal analysis based circuit design

Methods and apparatuses for transient analyses of a circuit using a hierarchical approach. In one embodiment, the cells are grouped locally on the power supply network according to average power dissipation. A time varying current of each cell group is estimated using a probabilistic approach to represent the cell group so that the probability of a more severe waveform for the current of the cell group is under a certain level. For example, the cells in a group are partitioned as switching cells and non-switching cells using cell toggle rates for the determination of the time varying current. The circuit model of the power supply network includes the current sources according to the estimated time varying currents for the cell groups, the power supply wire resistance, the power supply to ground wire capacitance, well capacitance and the de-coupling capacitance from non-switching cells.

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Fremont, CA, United States of America

Khalid Rahmat