Patent ID: 6239607
Filing Date: 2001-05-29
Classification: G01R

Abstract:
A method for operating a data processing system to provide an estimate of the leakage current expected from an integrated circuit comprising a plurality of N and P type transistors, each of said transistors having a conducting and non-conducting state determined by a signal present on the gate of said transistor, said non-conducting state being characterized by the size of said transistor, said method estimating the leakage current expected when said integrated circuit is connected to a testing circuit, said testing circuit providing test signals to said integrated circuit, said method comprising the steps of:generating a graph comprising a plurality of vertices connected by edges, each edge representing a source-drain connected transistor connected between two nodes as a switch having a resistance that depends on whether said transistor is ""on"" or ""off"" when said test signals are present, said graph having a first node connected to a terminal maintained at a first power supply potential and a second node connected to a terminal maintained at a second power supply potential, the difference of said first and second power supply potentials being denoted by V.sub.DD, each node in said graph being assigned, using logic simulation, a value of 0 or 1, together with the strength of that value, said nodes connected to said first power supply being assigned a value of 1 and a maximum strength value and said nodes connected to said second power supply being assigned a value of 0 and a maximum strength value;generating a leakage current estimate for each path connecting said first and second nodes; andcombining said leakage current estimates to arrive at said estimate of the leakage current of said integrated circuit, wherein said step of generating a leakage current estimate for each path connecting said first and second nodes comprises the step of:setting said leakage current estimate for one of said paths equal to the leakage current through a non-conducting transistor having a potential difference between the source and drain thereof, referred to as V.sub.DS, such that V.sub.DS =V.sub.DD if that path contains such a transistor, said leakage current depending on V.sub.DS, said type of transistor, and the size of said transistor.