A Novel Transformer less Interleaved High Step-Down Conversion Ratio DC-DC Converter with Low Switch Voltage Stress

Abstract: A novel transformer less interleaved high step-down conversion ratio dc-dc converter with low switch voltage stress has been presented. In this converter, two input capacitors are series-charged by the input voltage and parallel discharged by a new two-phase IBC for providing a much higher step-down conversion ratio without adopting an extreme short duty cycle. Based on the capacitive voltage division, the main objectives of the new voltage-divider circuit in the converter are both storing energy in the blocking capacitors for increasing the step-down conversion ratio and reducing voltage stresses of active switches. As a result, the presented converter topology possesses the low switch voltage stress characteristic. This will allow one to choose lower voltage rating MOSFETs to reduce both switching and conduction losses, and the overall efficiency is consequently improved. Moreover, due to the charge balance of the blocking capacitor, the converter features automatic uniform current sharing characteristic of the interleaved phases without adding extra circuitry or complex control methods. Here interleaved buck converter and its operation are discussed. Also comparisons with conventional interleaved buck converter and simulation results are included.

Keywords: DC-DC Converter, MOSFETs, buck converter.