INDUCTORLESS DC-TO-DC-CONVERTER WITH HIGH-POWER DENSITY

A new type of switching-mode power supply containing no inductors or t ransformers is proposed. The controlled transfer of energy from a unre gulated dc source to a regulated output voltage is realized through a switched-capacitor (SC) circuit. A duty-cycle control is used: the dri ving signals of the transistors in the SC circuit are determined by th e feedback circuit. The absence of magnetic devices makes possible the realization of converters of small size, low weight and high power de nsity, able to be manufactured in IC technology. High efficiency, smal l output voltage ripple and good regulation for large changes in the i nput voltage and/or load values are other positive features of the new type of dc-to-dc converter. The input-to-output voltage conversion ra tio is flexible: The same converter structure can provide a large rang e of constant desired values of the output voltage for a given input v oltage, by predeterming the steady-state conversion ratio. The frequen cy-response shows good stability of the designed converter. The experi mental results obtained by using a prototype of a step-down SC-based d c-to-dc converter confirmed the theoretical expectations and the compu ter simulation results.