This paper introduces the flying-capacitor dc-dc boost converter. In the proposed topology, a high voltage gain ratio and improved conversion efficiency are achieved with low inductor core and copper losses. The input current ripple of the new converter is low while its ripple frequency is high, yielding a low-sized input filter. Furthermore, the voltage stresses on the power switches and diodes of the proposed converter are considerably low. It is shown that the proposed converter can be extended to higher stages to achieve a higher voltage gain ratio at enhanced efficiency. The principle of operation of the new converter is proposed, and the comparison with the conventional boost topology is presented. A complete analysis of this converter in the steady state and small signal operation is performed as well. Simulation results and a design example are also given to demonstrate the effectiveness of the proposed power converter.