In this paper, the philosophy of the heterogeneous control combined with landmark description is applied for controlling dc-dc converters. In our approach, there are combined fuzzy logic approach with some crisp information regarding the system evolution, the so called landmark based representation. On this structure seven behavioural items are defined, allowing delimiting the so called fundamental functioning regions in the state space of the converter. The necessary and sufficient conditions for steady state evolution are determined. The qualitative properties of these regions are established and a nonlinear heterogeneous controller is designed. Experimental results are presented pointing out the advantages of the proposed method.

Keywords: Heterogeneous control, Fuzzy logic control, Sliding mode, DC-DC converters, Qualitative description, Identification