An Improved Cascade Buck Converter for High Step-Down DC-DC Applications

This article focuses on the efficiency improvement of the cascade buck converter (CBC). By changing the position of the second stage inductor, the output current is shared between both the first and second stage inductors and as a result, the total volume of the magnetic components and their conduction losses are decreased. Besides, by proper design of the inductors, the frequency of the output current ripple will increase to twice the conventional CBC with lower p-p amplitude, which results in a further decrease in the size of passive components. The proposed improved CBC is analyzed, and its operating principles are presented. The theoretical analysis is verified by the experimental results of a 400-V input and 24 V–120 W output prototype converter.