Topology-Based Accurate Modeling of Current-Mode Voltage Regulator Modules for Power Distribution Network Design

• Published in: IEEE transactions on electromagnetic compatibility Vol. 64; no. 2; pp. 524 - 535
• Main Authors: Sun, Jingdong, Yan, Yimajian, Wang, Hanfeng, Chen, Emil, Wu, Ken, Fan, Jun
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Circuit boards; Current-mode control; device modeling; Electric power distribution; Electronic systems; Impedance; Inductors; Integrated circuit modeling; Load modeling; Model accuracy; Modelling; Modules; Network design; power distribution network (PDN); power integrity; Topology; Transient analysis; Transient loads; Voltage control; voltage regulator module (VRM); Voltage regulators
• ISSN: 0018-9375; 1558-187X
• DOI: 10.1109/TEMC.2021.3123338

Power distribution network (PDN) is essential in electronic systems to provide reliable power for load devices. Thus, modeling of PDNs in printed circuit boards and packages has been extensively studied in the past few decades. However, with the higher integration levels and operation bandwidths of modern voltage regulator module (VRM), there lacks an accurate model for transient load responses based on the widely used current-mode control topology. In this work, a topology-based behavior model, including both the power stage and control loops, is developed for the current-mode buck VRM. A novel method is also proposed to unify the modeling of the continuous and discontinuous conduction modes for transient load responses. Through the measurement-based characterization, the model parameters are optimized to match with the actual design. Furthermore, this model can be applied to both the time-domain and frequency-domain circuit simulations to predict the voltage droop and output impedance, respectively. The accuracy of the model is validated using an evaluation board containing the single-phase and multiphase VRMs. The proposed model for current-mode control VRM can be easily cascaded with other PDN components to enable a combined PDN analysis.