Step-up/step-down DC-DC converter with near zero input/output current ripples

A novel single switch two diode wide conversion ratio step down/up converter is presented. The proposed converter is derived from the conventional single-ended primary inductor converter (SEPIC) topology, and it can operate as a capacitor-diode voltage multiplier, which offers simple structure, reduced electromagnetic interference (EMI), and reduced semiconductor voltage stress. The main advantages of the proposed converter are the continuous input/output current, higher voltage conversion ratio, and near-zero input and output current ripples compared with the conventional SEPIC converter. The absence of both a transformer and an extreme duty cycle permits the proposed converter to operate at high switching frequencies. Hence, the overall advantages will be: higher efficiency, reduced size and weight, simpler structure and control. The theoretical analysis results obtained with the proposed structure are compared with the conventional SEPIC topology. The performance of the proposed converter is verified through computer simulations and experimental results. Copyright (c) 2012 John Wiley & Sons, Ltd.