Power estimation tool for sub-micron CMOS VLSI circuits

Accurate and fast time-domain current waveform simulation is important for the design of reliable CMOS VLSI circuits. Previous approaches for switch level current simulations used simple current models that did not match accurately the supply current. In this paper, we present a detailed current model that resulted in a maximum of 10% deviation from the current waveforms as obtained by SPICE LEVEL 3, at peak values and 5% on the average current. Our current model accounts for short-channel effects, input rise times, short-circuit and dynamic current and circuit topology. Moreover, our model produces piecewise linear current waveforms and hence can be easily incorporated in any switch-level simulator. Using our models in an event driven simulator we achieved 3-4 orders of magnitude speed-up relative to SPICE LEVEL 3. Our results forcurrent waveform accuracy outperform previously published methods and in particular for complex CMOS circuits.