Switched-capacitor quadratic buck converter for wider conversion ratios

Low voltage and high current are typical requirements for the input source of the new family of microprocessors; therefore there is the need to develop new topologies and control strategies that can meet such requirements. A narrow duty ratio has limited the application of the conventional buck converter for wider step-down DC-DC conversion. An interesting option is to consider the quadratic buck converter; however, there is still the problem to obtain a wider step-down conversion. In this study, a switched-capacitor quadratic buck converter is proposed such that a wider conversion ratio is obtained for lower-output voltages. The converter consists of a quadratic buck converter with an array of capacitors and diodes, also referred as a voltage multiplier. To illustrate the behaviour of the proposed converter, experimental results are shown for a conversion from 36 to 1.5 V and an output power of 30 W. The efficiency of the proposed converter can be effectively increased when soft-switching and synchronous rectification are implemented.