Single-Stage Non-Isolated High Conversion Ratio Step-Down Converter for Voltage Regulation Modules

This paper proposes a non-isolated converter with an ultra-high step-down voltage conversion ratio and low voltage stress on switching devices, achieved within a moderate duty cycle for voltage regulation modulators (VRMs). By incorporating clamping capacitors and additional inductors into the buck converter topology, the proposed design achieves a significantly higher step-down conversion ratio while reducing voltage stress and improving efficiency. In the proposed converter, the clamping capacitors store energy to act as a voltage source, thereby reducing voltage stress on the switching devices. While the main inductor serves as the primary component for energy transfer to the output, additional inductors are connected in parallel to reduce the burden on the clamping capacitors, reduce current stress, and ensure natural balance. Furthermore, the switch network is scalable to achieve the desired voltage conversion ratio, depending on the application. Finally, a 48V-to-1.5V/25W prototype operating at 300kHz was developed and tested, demonstrating the feasibility of the proposed converter.