Scheduling of Hybrid Battery-Supercapacitor Control Instructions for Longevity in Systems with Power Gating

The in-rush current due to wake-up of power gating (PG) components causes faster discharge of battery. This work introduces an instruction controlled hybrid battery-supercapacitor (B-SC) system for longer battery life in systems with instruction controlled PG. Two instructions have been introduced along with architectural support. The first instruction disconnects the battery from the PG components if the charge in the supercapacitor greater than or equal to the charge required by wake-up of PG components. The other instruction connects the battery to the PG components for recharging the supercapacitor. Disconnecting the battery during wake-up minimizes rate capacity effect (C-rate) for longer battery life. An algorithm is designed to schedule the proposed battery control instructions within a program having PG instructions. The efficacy of the proposed method is evaluated on MiBench and MediaBench benchmark programs. The proposed method reduces C-rate by an average of 14.25% at the cost of average performance loss of 6.87%.