This paper presents a new topology of soft-switching two-switch Forward converter associated to a quadratic Boost converter, which provides large voltage step-up (from 12Vdc to 80Vdc). The combination of the stages results in a switched-mode power supply (SMPS), whose output voltages are +200Vdc and -200Vdc. The inverter put in these converter is very fast and simple, because it has a little components quantity, and this form can be said that this control is very robust, and in the other side, the control presents a low cost. The little volume presented in this converter present other important thing, because it has a small volume and this form, have a big energy density. The operation of this converters are analyzed, as some results concerning the proposed SMPS with output AC are presented.