A new type of isolated step-up converter with high voltage gain is proposed in this paper. An isolated DC-DC converter with Continuous Current Mode Current source Inverter with a Voltage Multiplier with minimum Capacitance is designed for Current sources like Fuel Cells, emerging non conventional type of sources. A new design method of half-wave Cockcroft-Walton (H-W C-W VM) that lays on the calculation of the optimal number of stages, which is necessary to produce the desired output voltage with the minimum total capacitance value, is dealt in this project. For this purpose, an adequate choice of the capacitance values per stage is considered, leading to the investigation of four different cases. In this converter, the output to input voltage ratio, for a given duty cycle; can be raised by adding voltage multiplier stages of capacitors. This proposed technique compensates for control circuit delay, and hence, turns on power MOSFET at the instant exactly when drain-to-source voltage becomes zero using the parasitic capacitance of the switches and the leakage inductance of the transformer. The operating frequency of the converter is 100 KHz. Thus unlike conventional method, Ferrite Core transformers are used which reduces the number of turns increasing the power density. The circuit for current source inverter with the voltage multiplier is simulated in PSPICE SOFTWARE and the results obtained were verified with the hardware model. For an input voltage of 30V and input current of 5 Amps, the output from the inverter is 40 V and output from the voltage multiplier of three stages is 230 V and 0.6 Amps. © 2011 IEEE.