In this paper, an interleaved soft-switched active-clamped L-L type current-fed half-bridge dc-dc converter has been proposed. The L-L type active-clamped current-fed is able to maintain zero-voltage switching (ZVS) of all switches for the complete range of wide fuel cell stack voltage variation at full load down to light load Active-clamped circuit absorbs the turn-off voltage spike across the switches. topology maintains higher efficiency due to lower conduction losses. Soft-permits higher switching frequency operation, reducing the size, weight and of the magnetic components. Interleaving of the two isolated converters is done using input series output approach and phase-shifted modulation is adopted. It reduces input current ripple at the fuel cell input, which is required in a fuel cell system and reduces the output voltage ripples. In addition, the size of the magnetic/passive current rating of the switches and voltage ratings of the rectifier diodes are (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.