The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Dec. 03, 1996

Filed:

Mar. 05, 1996
Applicant:
Inventors:

Cyrus Bamji, Fremont, CA (US);

Ravi Varadarajan, Fremont, CA (US);

Assignee:

Cadence Design Systems, Inc., San Jose, CA (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F / ;
U.S. Cl.
CPC ...
364490 ; 364488 ; 364489 ; 364491 ;
Abstract

Overconstraints in a system, such as an electrical circuit layout, are identified using port abstraction graphs. Intercell pitchmatching constraints are represented by meta-edges between cells. Classes of edges which can be represented by a support edge are created, and the value of the class edges are increased to the value of the support edge. The edge values are updated in the graphs, and the redundant edges eliminated. Overconstraints are identified as positive cycles in the graphs, and a database of the layout is annotated and graphically displayed. The graphical display responds to user inputs to manipulate the display of the relations between constraints. The use of the port abstraction graphs also reduces the number of equations that need to be solved to compact the layout.


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