Fast and noise-aware power-up for on-die power gated domains

On-die PSO is used for leakage power reduction. The power-up process at PSO exit (gated supply voltage recovery) is usually designed to be relatively slow process. This is done in order to keep quiet continuous power supply of always powered-on devices. We propose a way of acceleration the power-up, while holding the continuous power supply at acceptable level of noise. This is achieved by monitoring the IR droop level of the continuous power supply. It allows significant reduction of the power-up time with no functionality impact. The theoretical background, the arrangement schematics and the simulation results are presented.