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:
Aug. 02, 2005

Filed:

Jul. 27, 2001
Applicants:

Norman Chang, Fremont, CA (US);

Shen Lin, Foster City, CA (US);

Osamu Nakagawa, Redwood City, CA (US);

Weize Xie, Cupertino, CA (US);

Inventors:

Norman Chang, Fremont, CA (US);

Shen Lin, Foster City, CA (US);

Osamu Nakagawa, Redwood City, CA (US);

Weize Xie, Cupertino, CA (US);

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F009/00 ; G06F009/24 ;
U.S. Cl.
CPC ...
Abstract

A method determines a plurality of clock delay values. Each delay value is associated with a delay element on a clock line leading to a clock sink in a synchronous circuit. The method determines an initial set of delay values and executes an optimization algorithm, beginning with the initial set of delay values, to arrive at a set of delay values that at least approximately meets an criteria while satisfying timing constraints associated with selected pairs of logically connected clock sinks. In a preferred form, the optimization algorithm is a genetic algorithm or a gradient descent algorithm. The genetic algorithm involves selecting parent sets of delay values, crossing over so as to produce a child set of delay values, mutating the child set of delay values, evaluating how well the child set of delay values meets the criteria, and conditionally discarding the child set on the basis of the evaluating step. The gradient descent algorithm involves perturbing the initial set of delay values, evaluating how well the perturbed set of delay values meets the criteria, and conditionally discarding the perturbed set on the basis of the evaluating step. If the perturbed set is not discarded, then the gradient descent algorithm adjusts the values of the perturbed set in the same direction relative to the corresponding values in the initial set.


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