Short-Circuit Current Modeling for CMOS Standard Cells Power Characterization

Short-circuit currents contribute signiicantly to the total power consumption of CMOS circuits. In this paper we describe a procedure to characterize libraries of standard cells in order to extract information on the power dissipation to be used later in logic-level simulators. Ours is a black box approach in which cells are characterized without looking at the internal nodes. The objective is to build a cell's energy view depending on two variable parameters: the load and the slope of the signal at the output of the cell. This characterization allows a post-simulation power evaluation because the two variables, load and slope at the output, are independent of the history of the circuit, temporal-correlation of the input signals, and the energy dissipated is calculated independently by the simulation engine. The experimental results show that an acceptable level of accuracy is obtained when the cells are not overloaded and the slope of the signals is close to that of the typical slope. This should always be the case in a good design.