Abstract
We present a vector selection methodology for estimating the peak power dissipation in a CMOS logic circuit. The ultimate goal is to combine the speed of RT-level simulation with the accuracy of low-level power simulation. We rely on efficient RT-level peak power prediction heuristics to select a handful of input vector pairs from the simulation testbench. These vector pairs are highly likely to induce the worst-case peak power. After that, the low-level power simulation is performed only with these peak power candidate vector pairs to obtain the realistic peak power values. Computationally, there are three major stages in our methodology. Firstly, we analyze the structure of the circuit and calculate the peak power weight for each input pin so as to construct a so-called mountain-based model. Secondly, we perform waveform composition to compute the peak power metric for each given input vector pair. Finally, we select a few candidate vectors for low-level power simulation. By doing so, the time-consuming simulation at the low levels can be mostly avoided without losing accuracy. Experiment results show that only less than 1% of the total functional patterns defined in a testbench are needed to be selected for low-level power simulation in order to achieve 100% accuracy.