IDAP: a tool for high-level power estimation of custom array structures

While array structures are a significant source of power dissipation, there is a lack of accurate high-level power estimators that account for varying array circuit implementation styles. We present a methodology and a tool, the implementation-dependent array power (IDAP) estimator, that model power dissipation in SRAM-based arrays accurately based on a high-level description of the array. The models are parameterized by the array operations and various technology dependent parameters. The methodology is generic and the IDAP tool has been validated on industrial designs across a wide variety of array implementations in the e500 processor core (e500 is the Motorola processor core that is compliant with the PowerPC Book E architecture). For these industrial designs, IDAP generates high-level estimates for dynamic power dissipation that are accurate with an error margin of less than 22.2% of detailed (layout extracted) SPICE simulations. We apply the tool in three different scenarios: 1) identifying the subblocks that contribute to power significantly; 2) evaluating the effect of bitline-voltage swing on array power; and 3) evaluating the effect of memory bit-cell dimensions on array power.