Time-stamped transition density for the estimation of delay dependent switching activities

We propose a new method to improve the accuracy of the transition density for the estimation of delay dependent switching activities in combinational circuits. In the previous method, glitching sensitivity concept was defined and used to modify the transition density so as to generate and propagate the glitch. To account for the inertial delay effect, the same technique that is commonly used in logic simulators to filter out unacceptably short pulses was used. However, since it does not keep transition density at each occurrence time separately, it is not adequate for the accurate estimation of glitch and inertial delay effect. In addition, it underestimates the difference between probabilistic property of the transition density and the deterministic property of signals in logic simulations in computing inertial delay effect. We describe the problems of the previous methods and propose a new method called time-stamped transition density to solve the problems. We also show the extensions of the method to consider possible delay variation due to imperfections in the manufacturing process. The experimental results demonstrate the validity of our proposed method