The DC-DC converter can exhibit nonlinear phenomena such as chaos and periodic motion, which are influenced by system parameters, topological structure, load and pulse period. The presence of chaos can lead to instability or failure of the converter, therefore the study of such phenomena is meaningful. This paper presents a novel investigation of the current-controlled DC-DC boost converter with a switched inductor, employing the switching theory of flow. The analytical conditions governing the switching motion at both the collision boundary and the time boundary are developed. The phase plane and boundary in the absolute domain of the system are determined on the basis of the switching conditions of the motion state. The bifurcation diagram is used to visualize the effects of the reference current and supply voltage on the converter, and the range of stable operation can thus be obtained. The trajectories of boundary collisions are depicted in detail by employing the mapping structure, and the collision moments and system parameters are determined. The results demonstrate that for the current-controlled boost converter, which exhibits a high degree of dynamical complexity at the collision boundary, a trajectory from periodic to multiply-periodic to chaotic at the boundary is followed. The G-functions are intimately connected to boundary motion and the structure of mappings. Consequently, the system's switching behavior can be effectively analyzed through G-functions. This analysis further substantiates the intrinsic relationship collision motions occurring at distinct mapping boundaries.