Design and control methodology for fine grain power gating based on energy characterization and code profiling of microprocessors

This paper presents a design and control scheme of a microprocessor whose internal function units are power gated at instruction-by-instruction basis. Enabling/disabling the power gating is adaptively controlled under the support of on-chip leakage monitors and the operating system to minimize energy overhead due to sleep-in and wakeup. Measured results of the fabricated chip in the 65nm CMOS technology demonstrated that our approach reduces energy to 21-35% in the range of 25-85°C as compared to the non power-gated case. Energy dissipation was reduced by up to 15% as compared to the conventional fine-grain power gating technique in the same temperature range.