This work demonstrates a modified split-phase switching scheme which maintains complete soft-charging operation when applied to a dual inductor hybrid-Dickson (DIH) switched-capacitor converter, while simultaneously greatly increasing the allowable fly capacitor voltage ripple and subsequent passive component utilization. Dissimilar to previous DIH split-phase demonstrations which sequentially introduce capacitive elements as a switching phase progresses, here all fly capacitors are inserted upon initialization of each phase, with select capacitors being disengaged before each phase's conclusion. As a result no switches experience a periodic reverse bias. This work includes analysis directing this insight along with a hardware prototype that achieves a peak efficiency of 93.8% (87.5%) at 750kHz switching frequency, for 48V-to-3V (1V) conversion. Effective capacitor utilization and complete soft-charging is verified experimentally, and a power density of 54.4 kW/liter (892W/inch ) at 3V output is recorded despite the use of stable Class I (C0G/NP0) dielectric capacitors and oversized inductors with minimal current ripple for simplified analysis.

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 inch3 demonstrates very high measured power densities of 768 W/in3, 751 W/in3, and 598 W/in3 for regulated output voltages of 3V, 2V, and 1V respectively while switching at a frequency of 750kHz.

This work introduces a resonant Dickson-type converter topology whose flying capacitors provide dielectric isolation between input and output terminals. For even conversion ratios, it achieves complete soft-charging of all of its flying capacitors with a convenient 50% duty cycle. Additionally, switch count is reduced relative to prior work and no distributed bypass capacitor column is required. Moreover, this topology actively drives both of its inductors without the requirement for mutual coupling between magnetic elements. A discrete 4:1 hardware prototype designed for 48 V up to rectified US mains applications is demonstrated and achieves a high power density of 2,010 W/in3 with a 140 V input voltage and 941 kHz switching frequency.

In this work we demonstrate a synchronous bootstrap power delivery scheme applied to a high level count GaN-based flying capacitor multi-level (FCML) converter. The proposed approach is well suited for high-frequency operation as it eliminates conventional boot-strap diodes and allows for precise on-time control for a maximized conduction duration. Importantly, we note the synchronous boot-strapping scheme's capability for bi-directional energy transfer: Gate driver power can be injected into the chain from either a ground referenced supply, a high-side line referenced supply, or both simultaneously for further reduced voltage droop. A discrete 6-level FCML hardware prototype switching at 500 kHz (2.5 MHz effective) is designed and constructed to validate this approach. A maximum deviation in supply voltage of 156 mV throughout all 10 series stacked gate drivers for converter duty ratios spanning 15-85% is measured. Subsequently the need for local regulation throughout the gate-drive chain is eliminated, which in turn improves efficiency, simplifies design, and reduces cost.

This paper presents a regulating Hybrid Switched Capacitor Converter (HSCC) topology suitable for high conversion ratio Point-of-Load (PoL) applications, specifically targeting 48 V to 1 V power delivery in space-based high-performance computing systems, where size and weight are important considerations, along with device de-rating for radiation tolerance. The proposed topology merges an initial 2:1 switched capacitor conversion stage with a recently developed symmetric dual inductor hybrid (SDIH) conversion stage, reaping benefits of both. The SDIH stage offers reduced component count and an excellent switch stress figure of merit, while the initial 2:1 voltage reduction stage significantly reduces the volume of flying capacitors, enabling compact size and low weight. A high density gate drive solution is also presented, using a minimal number of driver ICs without compromising on driving capability. A preliminary hardware prototype demonstrates this topology's feasibility while employing de-rated gallium nitride (GaN) switches to safeguard against radiation total ionizing dose (TID) and single event effects (SEE). This prototype achieves a very high measured power density of 2,020 W/inch3 (123.3 kW/liter) while performing 48 V to 1 V conversion and switching at 1 MHz.

In this work, we present a robust gate drive power delivery approach well-suited for converter topologies, such as the flying-capacitor multi-level (FCML) converter, that contain several series-connected switching elements. The proposed power delivery network leverages internal voltages inherent to the FCML topology in combination with a charge-pump mechanism to provide gate drive power with high efficiency. The charge-pump design operates independently of the primary switching devices, allowing the converter to operate at very low duty ratios without suffering from significant degradation of the floating supplies. The concept is validated in a hardware prototype, demonstrating an estimated 38% reduction in gate drive power delivery losses compared to competing techniques. Moreover, the robustness of the technique is validated through incorporation into a 400V, 2kW 6-level FCML DC-DC converter, achieving a 99.07% peak conversion efficiency and 2.05kW/in power density.