Stability of On-Chip Power Delivery Systems With Multiple Low-Dropout Regulators

摘要

Low-dropout (LDO) voltage regulators have become prominent elements of on-chip power delivery systems due to the increasing importance of separate voltage domains, fast dynamic voltage scaling, and the need for high-quality power. As the number of LDOs sharing a common power network increases, the stability of the power grid can degrade if the resonance frequency due to the off-chip parasitic impedances is not sufficiently separated from the unity gain frequency of the regulator. In this paper, this source of instability in power delivery networks, consisting of multiple LDO regulators with a balanced load, is described. The effect of the number of LDOs on the resonance frequency of the power delivery network is evaluated to determine the stability of the system when the LDOs operate under similar load conditions.