In this paper the study of complex phenomenon in buck converter under voltage mode control, operating in discontinious current mode, within Matlab/Simulink simulation environments is provided. To perform simulations different types of models are used: based on discrete-time maps, differential equations and real elements (including different nonidealities). The main goal of this paper is to detect the ability of various Matlab/Simulink models to identify and to explore different types of complex behaviour, such as chaos and bifurcataions, in switch-mode DC-DC converters, as system parameters are changed, as well as to establish the possibilities of each model in this kind of investigation. Simulations are carried out by means of Matlab/Simulink simulation environment that provides wide range of blocks and elements for complete investigation procedure, including the implementation of all types of mentioned models and appropriate result data postprocessing and visualization. The verification of accuracy of developed models is based on the detection of Feigenbaum numbers. All models with definite level of precision are able to reveal that under certain circuit parameters period doubling route to chaos is observed.