The reaching law approach is broadly used for chattering repression, minimization of steady state error and reaching pace kept minimsed. The reasons of chattering, in this paper proposes sliding mode reaching law. In one hand, they assurance the scheme arrives at the sliding face swiftly and stay on it, in another way they deteriorate the chattering inefficiently, even matchless certainties and disturbances. This proposed reaching law gives uniqueness of the response. The reaching law is compared with Gao’s reaching law. Sliding mode reaching laws gives the efficacy in reducing the chattering of the variable structure control (VSC). This reaching law also reduces the losses in the switching diplomacy. In turns efficiency of the step-down converter increases. Simulation results give significant decrease of chattering and extremely fewer receptive in supply and load variation.