In this paper a piecewise-affine (PWA) power-Ioss-dependent inductance behavioral model is proposed, for ferrite-core inductors used in switch-mode power supplies (SMPSs). The model expresses the inductance as a function of easily measurable quantities. The PWA formulation leads to a faster computation with respect to the arctangent models available in the literature and allows analytically computing the inductor current based on its voltage. The model is validated through experimental measurements on a buck converter, showing a reliable prediction of the steady-state inductor current, under different SMPS working conditions.