A Symmetric Dual-Inductor Hybrid Dickson Converter for Direct 48V-to-PoL Conversion

This work introduces a new Symmetric Dual-Inductor Hybrid (SDIH) Dickson DC-DC converter topology that is suitable for large conversion ratios where regulation is required, such as direct 48V to Point-of-Load (PoL) applications. A Dickson-type switched-capacitor network is used to effectively produce two interleaved PWM drives with a greatly reduced voltage amplitude relative to the input line voltage, in turn allowing magnetic volume to be reduced while retaining modest switching frequencies. Both even and odd order switched-capacitor networks can be used with straight-forward split-phase switching allowing either network type to achieve complete soft-charging of all fly capacitors. Additionally, charge flow is well balanced through all elements, with equal capacitor and inductor values being preferred. Subsequently this topology is expected to simplify component selection, improve electrical and thermal performance, and reduce cost. A discrete prototype measuring 0.176 inch(3) demonstrates very high measured power densities of 768 W/in(3), 751 W/in(3), and 598 W/in(3) for regulated output voltages of 3V, 2V, and 1V respectively while switching at a frequency of 750 kHz.