On the general false path problem in timing analysis

Abstract

The false path problem is often referred to as the problem of detecting the longest sensitizable path (A path which is not, a false path is a sensitizable path). The term "false path" is not clearly defined. In this paper, we first give a clear and precise definition of a false path. Then the general false path problem is formulated. The general false path problem is to detect whether a given path (not necessarily the longest one) is a false path. We present an efficient algorithm for solving the general false path problem. We also propose another algorithm which generates all the possible sensitizable paths with the delays greater than a given threshold T. The efficiency and effectiveness of the proposed algorithm are demonstrated by the experimental results.

Tabu search based circuit optimization

“…The false paths reported in Du et al (1989), Perremans et al (1989), Huang et al (1993) and follow this approach.…”

“…As mentioned earlier, many techniques have been proposed for this purpose. We use the algorithm of Du et al (1989) and Yen et al (1989) with few modifications. The first modification is the use of a more accurate delay model (Youssef et al, 1995).…”

On timing-independent false path identification

“…Logic circuits typically contain a large amount of paths down which signals cannot propagate in functional mode, known as unsensitizable paths, or simply false paths [3,4]. These paths should not be considered during the design and test of integrated circuits (ICs).…”

“…Various automated false path identification (FPI) techniques have been presented to identify the other two types of false paths (e.g., [4,6,9,13]). When identifying delay-dependent false paths, we need to calculate the signal arrival times to determine whether the onpath signals are always dominated by side-input signals.…”

Removing user specified false paths from timing graphs

“…These false paths are caused by logic and temporal correlations between the circuit nodes. Although the complete identification of all such false paths in a circuit is an NP-complete problem, a number of exact or approximate methods have been proposed [2][3][4][5][6][7].…”