Patent ID: 7493434
Filing Date: 2009-02-17
Classification: G01R

Abstract:
1. A method for determining the value of a target signal at a point of a chip within an integrated circuit comprising the steps of: identifying a fanout cone from said point, to outputs of said chip, said point being arbitrary within said integrated circuit, where a fanout cone from said point is a collection of circuit elements of said integrated circuit whose respective states may be affected by a signal at said point, and where this effect is observable at outputs of said integrated circuit; sensitizing one or more paths in said fanout cone to cause the value of said target signal, or its inverse, to immediately appear at a set of two or more of said outputs (relevant outputs) without affecting value of said point; following said step of sensitizing, determining whether a discrepancy exists between value of said target signal reflected at one of said relevant outputs and value of said target signal reflected at another one of said relevant outputs created by said step of sensitizing or by a previous step of sensitizing; when said step of determining concludes that there is a discrepancy, reporting said discrepancy; and when said step of determining concludes that there is no discrepancy, reporting signal value of said target signal.