Filter capacitance reduction in DC/DC step-down reconfigurable Switched-Capacitor Converters by a balanced switching

A challenge for DC-DC converters miniaturization is the inability to integrate passive components on silicon due to their relatively large size at modern operating frequencies of some MHz. Switched Capacitor Converters may be a preferred choice for developing new miniaturized product formats because of their relatively small size and elimination of magnetic elements. The size and cost a DC-DC power supply are essentially defined by its bulky filter (storage) capacitor that is selected to meet output voltage ripple requirements. This paper investigates into filter capacitance reduction possibilities in different reconfigurable step-down capacitive converters by capacitor balanced switching. It is shown that balanced switching approach allows for filter capacitor reduction by 30-50% for an open-loop operation with a target voltage conversion ratio. Reducing filter capacitance also allows to speed up converter open-loop dynamic response.