Curvature-Based, Average Modeling of Switched-Capacitor Converters

A precise, curvature-based, average modeling technique for switched-capacitor (SC) dc–dc converters is proposed. The generalized modeling technique provides a comprehensive characterization of the converter at steady-state, across the full range of practical operating conditions. An expression for the equivalent output impedance is obtained, which relates the slow- and fast-switching limit impedances to the total output impedance. This expression can be used to accurately compute the output voltage without deriving the converter’s state equations and precisely weighs the contribution of each floating capacitor and parasitic resistance on the output impedance. The modeling technique is applied to a unity-gain SC converter, a multiphase binary converter, and a nonsymmetrical parallel–series converter, and the results are compared with existing steady-state models. The accuracy of the model is validated through simulations and experimental measurements.