Dynamic voltage scaling based on supply current tracking using fuzzy Logic controller

It has been demonstrated that dynamic voltage and frequency scaling (DVFS) leads to a considerable saving in dynamic and static power of a processor. In this paper, we present an adaptive framework that can be used to dynamically adjust supply voltage and frequency of a processor under different application workloads. Voltage scaling decisions are made by a fuzzy logic (FL) block based on variations of the processor's workload. By observing the supply-current of the processor and also its variation rate, the FL block can drive the processor to operate at the lowest possible voltage and also the corresponding minimum frequency, in which a specific application can meet all of its deadlines under time-constrained operation. As the voltage can change at the same time as the workload varies, significant savings in both dynamic and static power are achieved. Simulation results show that our approach outperforms a PID controller under distinct working loads

On-chip digital power supply control for system-on-chip applications

The authors presented an on-chip, fully-digital, power-supply control system. The scheme consists of two independent control loops that regulate power supply variations due to semiconductor process spread, temperature, and chip's workload. Smart power-switches working as linear voltage regulators are used to adjust the local power supply. The smart power-switch allows us to keep the global power network unchanged. It offers an integrated standby mode and has a fast dynamic response, i.e. low transition times between voltage steps at the cost of the reduced power conversion efficiency when compared to complex DC-DC converters