Tradeoff analysis and optimization of power delivery networks with on-chip voltage regulation

Integrating a large number of on-chip voltage regulators holds the promise of solving many power delivery challenges through strong local load regulation and facilitates systemlevel power management. The quantitative understanding of such complex power delivery networks (PDNs) is hampered by the large network complexity and interactions between passive on-die/package-level circuits and a multitude of nonlinear active regulators. We develop a fast combined GPU-CPU analysis engine encompassing several simulation strategies, optimized for various subcomponents of the network. Using accurate quantitative analysis, we demonstrate the significant performance improvement brought by on-chip low-dropout regulators (LDOs) in terms of suppressing high-frequency local voltage droops and avoiding the mid-frequency resonance caused by off-chip inductive par-asitics. We perform comprehensive analysis on the tradeoffs among overhead of on-chip LDOs, maximum voltage droop and overall power efficiency. We conduct systematic design optimization by developing a simulation-based nonlinear optimization strategy that determines the optimal number of on-chip LDOs required and on-board input voltage, and the corresponding voltage droop and power efficiency for PDNs with multiple power domains.