In power electronics, switching dynamical systems exhibit by nature a hybrid behavior. A hybrid dynamical system consists of a continuous component interacting with a discrete component. By taking into account this hybrid aspect, in this paper, we demonstrate the nonlinear dynamics of the voltage mode controlled Buck converter in an open loop. We mainly describe the transition scenario toward chaos. Through our simulation results based on Matlab-Simulink-Stateflow tool, period doubling bifurcation interrupted by border collision bifurcation is proved.