Wide-input high power density flexible converter topology for dc-dc applications

In this paper a highly flexible 2-phase step-down dc-dc converter topology designed for a wide range of point-of-load (PoL) applications is introduced. The new wide-input flying-capacitor based multi-level converter has smaller overall volume and better power processing efficiency than the conventionally used 2-phase interleaved buck solution, achieved through the reduction of voltage swings across its components. Compared to other multi-level solutions the new topology has much higher flexibility, allowing operating-condition dependent changes of the topology for efficiency optimization. Also, the silicon area required for the implementation of the switches is smaller than that of the other solutions, since all transistors are rated at ½ of the input voltage, further contributing to size reduction and power processing efficiency improvements. The advantages of the new topology have been experimentally verified with a wide input range, 3 V ≤ Vin ≤ 48 V, wide output range, 1 V ≤ Vout ≤ 12 V, output power Pout ≤ 72 W, 800 kilohertz switching frequency discrete experimental prototype. The results show that the introduced topology requires about 33% smaller inductor and 33% smaller output capacitor than the conventional 2-phase interleaved buck, while having higher power processing efficiency over the entire range of operation.