Showing papers on "Switched capacitor published in 2018"

A Self-Balanced Step-Up Multilevel Inverter Based on Switched-Capacitor Structure

Abstract: In this paper, a dc to ac converter with the ability of voltage increasing is presented. This inverter is designed in a way that just one dc source is used. Also, by using power storage technique and with combining charged capacitors and dc source in series form, output voltage levels can be increased. This inverter is in a modular structure and has the ability of capacitor's voltage self-balancing. H-bridge inverter was not used at the end of the proposed converter and all elements tolerate a voltage stress equal to the amount of input dc source. This leads to remarkable decrease of total standing voltage and peak inverse voltage. Other advantage of the proposed inverter is its potentiality of performance in high-frequency applications. The modular form of the proposed inverter provides the potentiality of extension to higher voltage levels and eases the maintenance. Moreover, considering to the fact that the stress of all components of the suggested inverter is equal to the input source, the performance in high voltage is added to the characteristics of the proposed inverter. The nine-level structure of the proposed inverter is simulated and laboratory test is carried out for the verification of its performance.

A New Boost Switched-Capacitor Multilevel Converter With Reduced Circuit Devices

Abstract: In this paper, a novel platform for the single phase switched-capacitor multilevel inverters (SCMLIs) is presented. It has several advantages over the classical topologies, such as an appropriate boosting property, higher efficiency, lower number of required dc voltage sources, and other accompanying components with less complexity and lower cost. The basic structure of the proposed converter is capable of making nine-level of the output voltage under different kinds of loading conditions. Hereby, by using the same two capacitors paralleled to a single dc source, a switched-capacitor (SC) cell is made that contributes to boosting the value of the input voltage. In this case, the balanced voltage of the capacitors can be precisely provided on the basis of the series–parallel technique and the redundant switching states. Afterward, to reach the higher number of output voltage levels, two suggested SC cells are connected to each other with a new extended configuration. Therefore, by the use of a reasonable number of required power electronic devices, and also by utilizing only two isolated dc voltage sources, which their magnitudes can be designed based on either symmetric or asymmetric types, a 17- and 49-level of the output voltage are obtained. Based on the proposed extended configuration, a new generalized version of SCMLIs is also derived. To confirm the precise performance of the proposed topologies, apart from the theoretical analysis and a complete comparison, several simulation and experimental results are also given.

High Step-Up DC–DC Converter With Active Switched-Inductor and Passive Switched-Capacitor Networks

Abstract: High-gain voltage conversion is a feature required for several applications, especially for power processing of low-voltage renewable sources in grid-connected systems. In this scope, the presented paper proposes a novel transformerless high gain step-up dc–dc converter based on an active switched-inductor and a passive switched-capacitor networks. The main advantages of the proposed converter are the high voltage gain (>10), the reduced voltage stresses across the switches and the reduced number of components when compared to topologies that provide the same voltage gain using similar principles. The detailed analysis of the proposed converter and a comparison considering other topologies previously published in the literature are also presented in this manuscript. In order to verify the proposed converter performance, a prototype has been built for a power of 200 W, input and output voltages of 20 and 260 V, respectively, and switching frequency of 50 kHz. Experimental results validate the effectiveness of the theoretical analysis proving the satisfactory converter performance, which peak efficiency is around 95.5%.

Single-Stage Switched-Capacitor Module (S 3 CM) Topology for Cascaded Multilevel Inverter

Abstract: A two-stage switched-capacitor based multilevel inverter possesses a drawback such that switches in the second stage (i.e., H-bridge) endure higher voltage stress. To resolve this problem, this letter proposes a single-stage switched-capacitor module (S3CM) topology for cascaded multilevel inverter, which ensures the peak inverse voltage across all the switches within the dc source voltage. A total of nine voltage levels can be generated with only one dc source and two incorporated capacitors. Hence, the number of isolated dc sources is significantly reduced compared to a cascaded H-bridge. In addition, voltage boosting gain of two is achieved. A comparative analysis of the recent topology reveals that the proposed S3CM topology achieves switch count reduction. The operation of the proposed topology is validated through circuit analysis followed by simulation and experimental results of a single-module (9-level) prototype.

Switched tank converters

Abstract: This paper presents a new class of Switched Tank Converters (abbreviated as STCs) for high efficiency high density non-isolated DC-DC application where large voltage step down (up) ratios are required. Distinguished from switched capacitor converters, the STCs uniquely employ LC resonant tanks to partially replace the flying capacitors for energy transfer. Full soft charging, soft switching and minimal device voltage stresses are achieved under all operating conditions. The STCs feature very high efficiency, density and robustness against component non-idealities over a wide range. Furthermore, thanks to the full resonant operation, multiple STCs can operate in parallel with inherent droop current sharing, offering the best scalability and control simplicity. These attributes of STC make it a disruptive and robust technology viable for industry's high volume adoption. A novel equivalent DCX building block principle is introduced to simplify the analysis of STC. A 98.92% efficiency STC product evaluation board (4-to-1, 650W) has been developed and demonstrated for the next-gen 48V bus conversion on data center server boards.

A Switched-Capacitor Bidirectional DC–DC Converter With Wide Voltage Gain Range for Electric Vehicles With Hybrid Energy Sources

Abstract: A switched-capacitor bidirectional dc–dc converter with a high step-up/step-down voltage gain is proposed for electric vehicles with a hybrid energy source system. The converter presented has the advantages of being a simple circuit, a reduced number of components, a wide voltage-gain range, a low voltage stress, and a common ground. In addition, the synchronous rectifiers allow zero voltage switching turn-on and turn-off without requiring any extra hardware, and the efficiency of the converter is improved. A 300 W prototype has been developed, which validates the wide voltage-gain range of this converter using a variable low-voltage side (40–100 V) and to give a constant high-voltage side (300 V). The maximum efficiency of the converter is 94.45% in step-down mode and 94.39% in step-up mode. The experimental results also validate the feasibility and the effectiveness of the proposed topology.

A Switched-Capacitor-Based Multilevel Inverter Topology With Reduced Components

Abstract: This letter presents an improved sensorless nine-level inverter topology with reduced number of components. It is formed by cascading a three-level T-type neutral clamped point inverter with a floating capacitor (FC) fed two-level converter unit. Additionally, two line-frequency switches are appended across the dc-link. A simple logic-form equations-based pulse width modulator is designed which is in-charge of maintaining the FC voltage at its reference value without any aid of voltage and current sensor. Thus, the complexity in control of the proposed topology is very minimal. The working principle of the proposed inverter and formulation of logic-form equations is deliberated in detail. Furthermore, experimental results obtained from the developed prototype are presented to validate feasibility and operability of the proposed topology. Finally, a comprehensive comparison with some of the recently reported inverter topologies proving the merits of the proposed topology is included.

An Analytical Method to Evaluate and Design Hybrid Switched-Capacitor and Multilevel Converters

Abstract: This paper investigates the use of multilevel conversion in dc–dc applications that require a large voltage conversion ratio. A quantitative method that can serve as a guide to compare and design multilevel topologies for large conversion ratio applications is presented. The proposed method keeps the conduction loss and switching loss constant across the different converters and employs the passive component volume as the single performance metric. As examples, flying capacitor multilevel converters and hybrid switched-capacitor (SC) converters are compared to conventional two-level buck converters, and are shown analytically to have significantly reduced passive component size. Three converter prototypes are implemented, based on the presented methodology to experimentally validate the method as well as demonstrate the advantages of multilevel and hybrid SC converters.

Symmetric/Asymmetric Hybrid Multilevel Inverters Integrating Switched-Capacitor Techniques

Abstract: In conventional hybrid multilevel inverters (MLIs), the voltage balance controls of floating capacitors are usually realized by redundant switching states using high-frequency modulation. The switching frequency, as well as the switching loss, is hence increased, and the topologies are limited to low-frequency output occasions as a result. In switched-capacitor MLIs (SCMLIs), the capacitors are self-balanced, since they are charged to fixed voltage levels by the input source directly or indirectly. By integrating switched-capacitor techniques into conventional hybrid MLIs, a pair of symmetric/asymmetric hybrid MLIs is proposed in this paper with boost ability. Complicated balance controls are avoided for capacitor voltages, and thus the modulation gets simplified. Compared with SCMLIs, the backend H-bridges that withstand the accumulated voltage stress are removed. The peak inverse voltages of devices are decreased, and thus only low-voltage components are needed. Meanwhile, the component numbers are reduced greatly. All these advantages contribute to high efficiency and reduced costs. Consequently, the proposed hybrid MLIs are especially appropriate for synthesizing a staircase output directly from an input source of low voltage. Analyses and their operational principles are firstly presented for the proposed topologies. Comparisons are then carried out to illustrate their superiority. To evaluate the performance, simulation and experimental prototypes are implemented, whose results confirm the feasibility of the proposed hybrid MLIs.

High Step-Up DC–DC Converter Based on Switched Capacitor and Coupled Inductor

Abstract: Due to the relatively low output voltage of photovoltaic (PV) source, a high step-up converter with high efficiency is needed when the PV source is connected to the power grid. A novel high step-up converter based on two switched capacitors and a coupled inductor is proposed in this paper. The operating principle is analyzed and the voltage gain is derived. A 100-W prototype is fabricated in the laboratory to verify the theoretical analysis, and the highest efficiency is 96.4%.

Analysis and Optimization of Star-Structured Switched-Capacitor Equalizers for Series-Connected Battery Strings

Abstract: Due to the adjacent cell-to-cell equalization, the classical switched-capacitor equalizer (SCE) has seriously low balancing speed and efficiency for a long battery string. Therefore, a series of star-structured switched-capacitor equalizers are proposed to achieve high balancing speed and efficiency independent of the cell number and the cell voltage distribution without significant influences on the size, cost, control, and reliability compared with the classical SCE. The proposed topologies use the least mosfet s and capacitors to achieve the most direct balancing paths between any two cells, being the optimal switched-capacitor structures. An analysis method for the slow switching limit and the fast switching limit impedances of the proposed equalizers is proposed to provide a theoretical guidance for the selection of the switching frequency. The inherent advantages of the proposed systems are the small size, low cost, simple control, high efficiency, fast speed, easy modularization, and high reliability. A prototype for four lithium-ion battery cells is set up. Experimental results show improved balancing performances with strong robustness. Moreover, the measured peak balancing efficiency is about 93.1% despite faster balancing speed.

Multi-Input Switched-Capacitor Multilevel Inverter for High-Frequency AC Power Distribution

Abstract: This paper proposes a switched-capacitor multilevel inverter for high-frequency ac power distribution systems. The proposed topology produces a staircase waveform with higher number of output levels employing fewer components compared to several existing switched-capacitor multilevel inverters in the literature. This topology is beneficial where asymmetric dc voltage sources are available, e.g., in case of renewable energy farms based ac microgrids and modern electric vehicles. Utilizing the available dc sources as inputs for a single inverter solves the major problem of connecting several inverters in parallel. Additionally, the need to stack voltage sources, like batteries or supercapacitors, in series which demand charge equalization algorithms, are eliminated as the voltage sources employed share a common ground. The inverter inherently solves the problem of capacitor voltage balancing as each capacitor is charged to the value equal to one of the input voltage every cycle. State analysis, losses, and the selection of capacitance are examined. Simulation and experimental results at different distribution frequencies, power levels, and output harmonic content are provided to demonstrate the feasibility of the proposed multilevel inverter topology.

Multimode Operation of Resonant and Hybrid Switched-Capacitor Topologies

Abstract: This paper presents an overview of resonant and hybrid switched-capacitor converters with a particular focus on multimode operation. The multimode approach is discussed as a tool to affect high efficiency and power density across a wide load range, provide variable regulation, and, as a general framework, to conceptualize the advantages and opportunities of the approach compared to more traditional dc–dc converters. A general analysis is provided to quantify the advantage of hybrid and resonant converters that factors in the tradeoffs between size and loss in the magnetic component and voltage stress on the active devices. A broader set of operating modes is presented that spans continuous and discontinuous conduction and includes resonant, quasi-resonant, and more traditional buck- or boost-like operation. A prototype flying-capacitor multilevel converter is presented to demonstrate the variety of operating modes and motivate important considerations such as voltage balance on the flying capacitors.

Implementation and Comparison of Symmetric and Asymmetric Multilevel Inverters for Dynamic Loads

Abstract: This paper implements and compares a symmetric hybridized cascaded multilevel inverter and an asymmetric multilevel inverter utilizing a switched capacitor unit for 17 level inverters. The symmetric hybridized multilevel inverter topology consists of a modified H-bridge inverter, which results in an increase in the output voltage to five level from the three level by using a bi-directional switch at the midpoint of a dual-input dc source. In the proposed asymmetric multilevel inverter, dc sources are replaced with the switched capacitor unit, which in turn boosts the output voltage and produces twice the voltage levels at the loads. The proposed topology with the staircase modulation technique has been verified using MATLAB–SIMULINK, and the results are experimentally executed with prototype models, which are interfaced with dSPACE RTI 1104. The results of the proposed topologies are experimentally obtained for steady state, and the performance of the same is tested under different resistive and inductive load disturbance conditions. The results substantiate that these multilevel inverter topologies are better stabilized during load disturbance conditions with low total harmonic distortion, a lesser number of switches, and increased output voltage levels, and these topologies well suit for renewable energy applications.

A Family of Resonant Two-Switch Boosting Switched-Capacitor Converter With ZVS Operation and a Wide Line Regulation Range

Abstract: In this paper, a family of resonant two-switch boosting switched-capacitor converters (RTBSCs) with ZVS operation and a wide line regulation range is proposed. Based on our previously proposed two-switch boosting switched-capacitor converters (TBSCs), only a small resonant inductor is added, while two bulky capacitor banks are replaced by two much smaller resonant capacitors. Furthermore, by operating RTBSC above the resonant frequency, the transistors are ZVS turned on and diodes are Zero-current-switching (ZCS) turned on / off . This eliminates the hard-switched phenomenon of TBSC, leading to reduced component size by increasing the operating frequency without sacrificing the overall efficiency. In addition, the voltage-gain range of the RTBSCs is largely expanded and hence the input-voltage range is increased remarkably for regulated output voltage applications. Meantime, the voltage stress on transistors and diodes remains low, equal to the input voltage. A 3X RTBSC prototype with maximum output voltage 150 V, maximum output power 140 W, and a peak efficiency of 98.3% was built. The analysis is verified by simulation and experimental results.

Step-up switched-capacitor module for cascaded MLI topologies

Abstract: This study presents a new module for cascaded multilevel inverters (MLIs) based on switched-capacitor technique. Charging of the capacitors in the proposed switched-capacitor cell is performed in a self-balancing form. Voltage boosting capability and generating bipolar voltage levels without requiring an end-side H-bridge inverter are remarkable benefits of the proposed topology. Thereby, semiconductors with lower-voltage ratings are applied in its circuit. Comparison of the proposed inverter with traditional topologies and other recently introduced MLIs shows that the proposed topology reduces the number of circuit elements and also total blocking voltage by switches. Moreover, the proposed inverter configuration and its operating principle, capacitance, and power loss calculations, and also topology extension to achieve higher levels are investigated in depth. Finally, an experimental prototype is built to verify the theoretical analysis and feasibility of the proposed topology.

An original transformer and switched-capacitor (T & SC)-based extension for DC-DC boost converter for high-voltage/low-current renewable energy applications: Hardware implementation of a new T & SC boost converter

Abstract: In this article a new Transformer and Switched Capacitor-based Boost Converter (T & SC-BC) is proposed for high-voltage/low-current renewable energy applications. The proposed T & SC-BC is an original extension for DC-DC boost converter which is designed by utilizing a transformer and switched capacitor (T & SC). Photovoltaic (PV) energy is a fast emergent segment among the renewable energy systems. The proposed T & SC-BC combines the features of the conventional boost converter and T & SC to achieve a high voltage conversion ratio. A Maximum Power Point Tracking (MPPT) controller is compulsory and necessary in a PV system to extract maximum power. Thus, a photovoltaic MPPT control mechanism also articulated for the proposed T & SC-BC. The voltage conversion ratio (Vo/Vin) of proposed converter is (1 + k)/(1 − D) where, k is the turns ratio of the transformer and D is the duty cycle (thus, the converter provides 9.26, 13.88, 50/3 voltage conversion ratios at 78.4 duty cycle with k = 1, 2, 2.6, respectively). The conspicuous features of proposed T & SC-BC are: (i) a high voltage conversion ratio (Vo/Vin); (ii) continuous input current (Iin); (iii) single switch topology; (iv) single input source; (v) low drain to source voltage (VDS) rating of control switch; (vi) a single inductor and a single untapped transformer are used. Moreover, the proposed T & SC-BC topology was compared with recently addressed DC-DC converters in terms of number of components, cost, voltage conversion ratio, ripples, efficiency and power range. Simulation and experimental results are provided which validate the functionality, design and concept of the proposed approach.

Analysis and Design of Zero-Current Switching Switched-Capacitor Cell Balancing Circuit for Series-Connected Battery/Supercapacitor

Abstract: To overcome the problem that the balancing performance of existing switched-capacitor (SC) cell balancing systems drops along with the increase in the number of series-connected battery cells, a novel SC cell balancing circuit is presented in this paper. The same as other SC balancing systems, only a pair of complementary square-wave signals is required to control the proposed circuit. With resonant SC design, all switches employed in the proposed balancing circuit operate under zero-current switching. The equivalent model is derived to reveal the balancing performance of the proposed balancing circuit. The system feasibility and theoretical analysis are verified by both of simulation and experimental results.

A resonant switched capacitor based 4-to-1 bus converter achieving 2180 W/in 3 power density and 98.9% peak efficiency

Abstract: Hybrid switched-capacitor (SC) converters are known to have the potential to achieve higher efficiency and higher power density than conventional SC and magnetic-based converters, thanks to the efficient utilization of both active and passive components. By comparing the total switch stress and the minimal passive component volume, the cascaded 2:1 resonant SC topology is found to be excellent for applications with large conversion ratio (e.g. data center power delivery). A 36–60 V input, 4:1 fixed ratio intermediate bus converter is built based on this topology. The prototype achieves 98.9% peak efficiency and up to 2180 W/in3 power density, both of which are significantly higher than the state-of-the-art.

High Step-Up DC–DC Converter With Active Soft-Switching and Voltage-Clamping for Renewable Energy Systems

Abstract: A novel high step-up dc–dc converter with a coupled inductor and a switched capacitor is proposed in this paper, which is widely used in the renewable energy system as the front-end stage for low voltage sources. The combinational employment of the switched capacitor and the coupled inductor makes high voltage gain achievable without extreme duty cycle, resulting in reduced voltage stress on power switches. Hence, mosfet s with low resistance $R_{{\rm{DS}}}{\rm{(ON)}}$ could be utilized as the main switch to reduce conduction loss. Meanwhile, due to the leakage inductance of the coupled inductor, the current falling rate becomes controllable, and the reverse-recovery problem of the output diode is alleviated. Importantly, by incorporating an active clamped-circuit, not only are voltage spikes caused by leakage inductance restrained, but also zero-voltage switching could be obtained for the main and auxiliary switches. Specially, the clamped circuit plays a role of energy transfer to boost the gain as well. Finally, a prototype with a power rating of 500 W is implemented to verify the performance of the proposed converter.

Single-phase multilevel inverter based on switched-capacitor structure

Abstract: This study proposes a new topology for multilevel inverters based on switched-capacitor structure. The proposed topology uses capacitor charged/discharged characteristic to boost the output voltage without employing magnetic elements. The proposed circuit configuration has fewer components, including switches, voltage sources, and capacitors comparing with the conventional similar topologies. A phase disposition pulse-width modulation method is used to enhance the output waveform quality of the proposed inverter. Nine-level and 17-level configurations are simulated. To verify the operating principle, the experimental results for a nine-level inverter topology are presented.

Switched-Capacitor Quasi-Switched Boost Inverters

Abstract: In this paper, two switched-capacitor quasi-switched boost inverters (qSBIs) are proposed. By adding one capacitor and one diode to the qSBIs, the proposed inverters achieve high voltage gain with low voltage stress on active switches, capacitors, and diodes. The proposed inverters can extend to n -cell for voltage gain improvement. The operating principle, steady-state analysis, and impedance parameter selections of the proposed inverter are presented. A full comparison between the proposed inverter and other impedance-source inverters is addressed. A 500-W prototype is built to verify the operating theory of the proposed inverter in both the standalone mode and the grid-connected mode. Simulation and experimental results validate the theoretical analysis.

A 1.24 $\mu$ A Quiescent Current NMOS Low Dropout Regulator With Integrated Low-Power Oscillator-Driven Charge-Pump and Switched-Capacitor Pole Tracking Compensation

Abstract: Supply regulation using low quiescent current linear regulators helps in extending the battery life of power aware applications with very long standby time. A 1.24 $\mu \text{A}$ quiescent current NMOS low dropout (LDO) that uses a hybrid bias current generator (HBCG) which boosts the bias current dynamically and adaptively to improve the transient response is presented in this paper. A bias-current scalable error amplifier with an on-demand pull-up/pull-down buffer drives the NMOS pass device. The error amplifier is powered with an integrated dynamic frequency charge pump to ensure low dropout voltage. A low-power relaxation oscillator (LPRO) generates the charge pump clocks. A novel switched-capacitor pole tracking (SCPT) compensation scheme is proposed to ensure stability up to maximum load current of 150 mA with a low-ESR 1 $\mu \text{F}$ output capacitor. Designed in a 0.25 $\mu \text{m}$ CMOS process, the LDO has an output voltage range of 1–3 V, a dropout voltage of 240 mV, and a core area of 0.11 mm2.

An Improved DC Solid State Transformer Based on Switched Capacitor and Multiple-Phase-Shift Shoot-Through Modulation for Integration of LVDC Energy Storage System and MVDC Distribution Grid

Abstract: This paper proposes an improved dc transformer (NDCT hereinafter) based on switched capacitor with reduced switches for the integration of low-voltage dc energy storage systems and medium-voltage dc power distribution grid. The topology, phase-shift (PS) shoot-through and multiple PS modulations, and voltage, current, and power characterizations, as well as commutation characterization and control strategy, are proposed and analyzed comprehensively. Compared with the traditional schemes, the proposed NDCT not only can enhance reliability and flexibility but can increase voltage adjustment and power transfer capabilities as well. Moreover, the current ripple performance and soft-switching performance are improved, and the number and capacity of switches are reduced, thereby increasing the efficiency and cost of the system. Finally, an NDCT prototype is built. Experimental results verify the correctness and effectively of the proposed solution.

A Switched Capacitor Energy Harvester Based on a Single-Cycle Criterion for MPPT to Eliminate Storage Capacitor

Abstract: A single-cycle criterion maximum power point tracking (MPPT) technique is proposed to eliminate the need for bulky on-chip capacitors in the energy harvesting system for Internet of Everything (IoE). The conventional time-domain MPPT features ultra-low power consumption; however, it also requires a nanofarad-level capacitor for fine time resolution. The proposed maximum power monitoring does not rely on the time-domain, but on logic criterion that can be simply determined by a finite-state machine where the maximum photovoltaic (PV) power occurs at minimum conversion ratio and maximum switching frequency. Single-cycle is used as the criterion to determine the magnitude of the output power. Practical concerns, such as self-startup and self-sustaining capabilities are here addressed by proper design of the reconfigurable switched capacitor power converter. A hysteretic control not only regulates the output, but also avoids the loading condition in IoE applications. This harvester simultaneously addresses the challenges including self-startup, self-sustaining capability, and regulated output without using a storage capacitor. Compared with various PV cells, the power conversion efficiency has a peak value of 72%, which remains above 60% for a wide harvesting voltage and power range. The chip area is as small as 0.552 mm2.

A Bridge Modular Switched-Capacitor-Based Multilevel Inverter With Optimized SPWM Control Method and Enhanced Power-Decoupling Ability

Abstract: Microinverters operating into the single-phase grid from new energy source with low-voltage output face the challenges of efficiency bottleneck and twice-line-frequency variation. This paper proposed a multilevel inverter based on bridge modular switched-capacitor (BMSC) circuits with its superiority in conversion efficiency and power density. The topology is composed of dc–dc and dc–ac stages with independent control for each stage, aiming to improve system stability and simplify the control method. The BMSC dc–dc stage, which can be expanded to synthesize more levels, not only features multilevel voltage gain but also partially replaces the original bulk input capacitor and functions as an active energy buffer to enhance power-decoupling ability between dc and ac sides. In dc–ac stage, the control strategy of optimized unipolar frequency doubling sine-wave pulse width modulation is proposed to improve the quality of output waveform. Meanwhile, the multilevel voltage phase has been optimized to further reduce the power loss. Finally, a prototype has been built and tested. Associated with the simulation, the experimental results validate the practicability of these analyses.

A Highly Integrated Series–Parallel Switched-Capacitor Converter With 12 V Input and Quasi-Resonant Voltage-Mode Regulation

Abstract: This paper presents an integrated circuit (IC) implementation of a hybrid switched capacitor converter based on a modified series–parallel architecture. The converter operates in a quasi-resonant mode to regulate a nominal 3.7 V output from a 12 V supply. The design uses zero-current detection and nested 1-b regulation to autotune the zero-current switching state, simplify the design of a digital voltage-mode control scheme, and achieve partial zero-voltage switching. The modified architecture is able to operate with single-voltage rated devices without degrading the voltage times current product of the converter. This paper discusses details of level shifting, gate driving, and bootstrapping for an all n-channel powertrain, including a precharge circuit, to facilitate safe startup. The converter IC was designed in 180-nm bulk CMOS with a 5 V option for power devices. It was tested in a flip-chip assembly with a 36 nH 0402 inductor to deliver up to 4.6 W at 87.5% efficiency at a power density of 0.23 W/mm3.