Abstract-Leakage power dissipation becomes a dominant component in operation power in nanometer devices. This paper describes a design methodology to implement runtime power gating in a fine-grained manner. We propose an approach to use sleep signals that are not off-chip but are extracted locally within the design. By utilizing enable signals in a gated clock design, we automatically partition the design into domains. We then choose the domains that will achieve the gain in energy savings by considering dynamic energy overhead due to turning on/off power switches. To help this decision we derive analytical formulas that estimate the break-even point. For the domains chosen, we create power gating structure by adding power switches and generating control logic to the switches. We experimentally built a design flow and evaluated with a synthesizable RTL code for a microprocessor and a 90nm CMOS device model both used in industry. Results from applying to a datapath showed that the break-even point that achieves the gain exists in the number of enables controlling the power switch. By applying the domains controlled by up to 3 enables achieved the active leakage savings by 83% at the area penalty by 20%.
One of the critical issues in MTCMOS design is how to estimate a circuit delay quickly. In this paper, we propose a delay modeling and static timing analysis (STA) methodology targeting at MTCMOS circuits. In the proposed method, we prepare a delay look-up table (LUT) consisting of the input slew, the output load capacitance, the virtual ground length, and a power-switch size. Using this LUT, we compute a circuit delay for each logic cell by applying the linear interpolation. Experimental results show that the proposed methodology enables to estimate the critical path delay in a good accuracy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.