The direct-conversion resonant switched capacitor architecture with merged multiphase interleaving: Cost and performance comparison

Abstract

Switched capacitor and resonant switched capacitor topologies have gained interest in recent years for highly integrated (monolithic) DC-DC converters, and more generally for a range of applications that require high density, high efficiency, and low cost. This work presents experimental and theoretical results for a new resonant topology that has architectural similarity to the more common 3-level buck converter. We further outline the prospects of using mergedinterleaving to reduce voltage ripple while maximizing the utilization of passive components. We present the results of an experimental prototype that can be configured as a switched capacitor, resonant switched capacitor, or resonant 3-level topology. Importantly, by constraining factors such as total cost of active and passive components, volumetric energy density, and other design factors, we attempt to provide a fair comparison of the respective converter prototypes for applications spanning DC power delivery, and power management for renewable energy applications such as photovoltaics and battery management.

Large Signal Analysis on Variations of the Hybridized Dickson Switched-Capacitor Converter

“…Using q H,max from Eqn. (34), we can calculate the maximum achievable capacitor utilization, η max , for the two-phase S-1L-direct topology discussed in Section IV. First α, β, and γ are solved for using the expressions for a i , v i , and c i , in (2), ( 20) and (27)(28), respectively.…”

“…Using ( 29)-( 32), the switching frequency is determined to be 1 MHz with a duty cycle of 57.14 %. A critical load resistance of 46.6 Ω is found using (34), representing the point at which switches S 2 and S 3 will begin to undergo a reverse bias if load current is increased further. This is confirmed in simulation by observing that the voltage on the node connecting the inductor to switches S 3 , S 4 and S 5 , (labeled V SW in Fig.…”

Design of fully integrated resonance switched capacitor converters in FDSOI technology

“…In the direct topology, the current of the inductor is in the same direction in charging and discharging phases. Hence, a DC current component exists which indicates that the power spectral density of the current is divided mainly between the DC and the switching frequency components [5].…”

“…Such conclusion can impose a constraint on the integrated resonance converter to have at least two phases to guarantee proper functionality of the system in the presence of inductive power access. In the multiphase direct circuit, the inductors can be merged into one inductor [5] as shown in Figure 1 (c). To compare between the performance specifications of the indirect and merged direct topologies, we consider an area A that will be used for the flying capacitor (C Fly ).…”

“…On the other hand, it reduces the switching losses by working at significantly lower frequencies with respect to SC converters with the same area while having the same output resistance. In the prior state-of-the-art [5], [6], the ReSC converters are only implemented with discrete inductors usually bumped on top of the die. Since the performance of ReSC is strongly dependent on the inductance quality factor (Q), the usage of the discrete inductor with quality factor about 10-20 would be an optimal solution.…”