Active system for compensation for IR drops

Abstract

The IR drop is an unresolved problem of all VLSI chips having meaningful power consumption. Variations in the chip current consumption and non-negligible supply and ground grids resistance usually cause IR induced local supply voltage sag and ground voltage elevation (supply and ground IR drop), which causes internal paths delay instability, and, in the case of low supply voltages, becomes critical.We propose active system for IR drop compensation, based on independent voltage boost circuits, taking care of the supply and the ground nets, and placed multiple times on the chip's current "starving" areas. It effectively compensates for fast IR drop components. Combination with the "remote sense" capability of the external power supply, it provides solution for static and slow IR drop components. Our system allows keeping automatically stable average supply voltage inside the chip close to the target, regardless of the current consumption transient. Hence, we can decrease the power supply static guard band, usually taken to compensate for the IR drops, that adversely affects the chip power consumption.