An improved dc-to-dc converter is provided comprised of two inductances, an input inductance in series with the input source and an output inductance in series with the load, and between the two inductances, two storage capacitances in series with the two inductances. Switching means alternately connect the junction between the input inductance and the first series capacitance, and the junction between the second capacitance and output inductance, to a junction common to the source and load. A third inductance is connected between the junction of the two capacitances and the return current paths for the source and load.
In one of the embodiments of the invention, all three inductances are combined on the same core thus comprising a single magnetic circuit with three windings. In another embodiment of the invention an isolation transformer is first used to replace the third inductance. Again, both input and output inductor and isolation transformer are merged into a single magnetic circuit with four windings. In any of the embodiments of the invention, a zero current ripple can be obtained at both the input and the output simultaneously by a proper design of the magnetic circuit. A new method of integrated magnetics design is then disclosed to improve performance of other converter structures by properly merging their magnetics components.