A novel asymmetrical three-level BUCK (ATL BUCK) converter for point-of-load (POL) application

This paper presents a novel, non-isolated step-down converter for the application of point-of-load (POL) voltage regulation. The new converter can achieve higher power density by utilizing a much smaller inductor compared with Buck converter in the POL application. A smaller inductor is achieved by increasing the effective operating frequency applied to the inductor by a factor of 4 and at the same time reducing the voltage applied to the inductor while maintaining the same switching frequency of control switches. The new converter uses two groups of interleaving switches to increase the effective operating frequency on the inductor and a flying capacitor to reduce the voltage across the inductor. The new switch topology is adopted because inductors take up much more space than active switches in a high power density power module [1][2]. A 12V-to-1V/1A prototype demonstrates that the proposed topology can use an inductor that is 77% less inductance than a conventional Buck Converter (i.e. only 23% of Buck's inductance is used in the prototype). Since two groups of switches are interleaved, the RMS (Root Mean Square) current in each group of control switches is reduced to half and the hotspot on the control switches is split into two.