Synopsys, Inc.

Carnegie Mellon University

Sonia Singhal

Cho Moon

Subramanyam Sripada

Amith Singhee

Rob A Rutenbar

Loa Mize

Individual mode timing constraints associated with a set of netlists are combined into merged mode timing constraints. An initial merged mode constraint is generated by combining timing constraints from individual modes. The initial merged mode includes the union of all timing constraints from individual modes that add timing relationships and the intersection of all timing constraints from the individual modes that remove timing relationships. Extraneous timing relationships are identified in the merged mode and eliminated by introducing timing constraints in the merged mode. Equivalence between the merged mode and the individual modes is verified by comparing timing relationships in the merged mode with timing relationships in the individual modes. The merged mode is considered equivalent to the individual modes if every timing relationship present in an individual mode is present in the merged mode and every timing relationship present in the merged mode is present in any of individual modes.

Automatic generation of merged mode constraints for electronic circuits

Automatic verification of merged mode constraints for electronic circuits

A method and system for rapidly modeling and simulating intra-die variations in an integrated circuit are disclosed. In one embodiment, each logic gate in an integrated circuit has a characteristic to be simulated, where the characteristic of the gate is a function of one or more parameters having intra-die variations. For each parameter, a model of intra-die variation of the parameter is generated such that a number of random variables in the model is compressed to a reduced number (r) of random variables based on a spatial correlation of the intra-die variation of the parameter. Then, using a Quasi Monte Carlo (QMC) technique, the integrated circuit is simulated based on the model of the intra-die variation of each of the one or more parameters.

Method and apparatus for rapidly modeling and simulating intra-die statistical variations in integrated circuits using compressed parameter models

Timing behaviors associated with constraints of circuits are compared to identify mismatches between circuit configurations. Aggregate sets of timing constraints associated with timing nodes are determined for timing paths between start points and end points. Precedence rules are applied to aggregate sets of timing constraints by applying precedence rules to interacting timing constraints. Aggregate sets of constraints for corresponding timing nodes are matched to determine if timing constraint mismatches exist between circuits. If aggregate timing constraints associated with start point, end point pairs are found to match, reconvergent points between the start point and end points are analyzed to see if aggregate constraints of timing nodes connected to reconvergent/divergent points match if timing exception matches are involved. Graph traversal algorithms allow efficient computation of aggregate timing constraints for timing nodes.

Comparing timing constraints of circuits

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Mountain View, CA, United States of America

Sonia Singhal