Ultra-dynamic Voltage scaling (UDVS) using sub-threshold operation and local Voltage dithering

Local voltage dithering provides near optimum savings when workload varies for fine-grained blocks. Combining this approach with sub-threshold operation permits ultra-dynamic voltage scaling from 1.1 V to below 300 mV for a 90-nm test chip. Operating at 330 mV provides minimum energy per cycle at 9× less energy than ideal shutdown for reduced performance scenarios. Measurements from the test chip characterize the impact of temperature on the minimum energy point.