Switching-mode DC-DC converter with switched-capacitor-based resonant circuit

A soft-switching dc-dc converter, in which the resonant capacitor is replaced by a switched-capacitor circuit, is presented. The new system incorporates a switching technique at zero-current or zero-voltage for each switch and an operation at constant switching frequency. The first feature is due to the presence of a resonant circuit, which shapes the switches' current and voltage waveforms in a sinusoidal form. It assures minimal switching losses. The switched-capacitor circuit determines a simple, discrete control, extends the region in which the soft-switching condition is fulfilled to large values of the load or small values of the input voltage, and prevents the current stress on the electronic devices from increasing with the input voltage. An original design approach allows for choosing the element values so as to get both soft-switching and regulation over a large range of input voltage and load values. Analysis, computer simulation and experiments indicate the operation principles of the new structure and render evident its performances, such as high efficiency and good regulation capability.