Topic
Switched capacitor
About: Switched capacitor is a research topic. Over the lifetime, 8832 publications have been published within this topic receiving 115142 citations.
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TL;DR: Double-tiered capacitive charge shuttling technique is introduced and applied to a battery system in order to balance the battery-cell voltages and MATLAB simulation shows a substantial improvement in charge transport using the new topology.
Abstract: The automobile industry is progressing toward hybrid, plug-in hybrid, and fully electric vehicles in their future car models. The energy storage unit is one of the most important blocks in the power train of future electric-drive vehicles. Batteries and/or ultracapacitors are the most prominent storage systems utilized so far. Hence, their reliability during the lifetime of the vehicle is of great importance. Charge equalization of series-connected batteries or ultracapacitors is essential due to the capacity imbalances stemming from manufacturing, ensuing driving environment, and operational usage. Double-tiered capacitive charge shuttling technique is introduced and applied to a battery system in order to balance the battery-cell voltages. Parameters in the system are varied, and their effects on the performance of the system are determined. Results are compared to a single-tiered approach. MATLAB simulation shows a substantial improvement in charge transport using the new topology. Experimental results verifying simulation are presented.
475 citations
16 Jul 2006
TL;DR: In this article, the performance of a switched-capacitor (SC) DC-DC converter's steady-state performance through evaluation of its output impedance has been investigated, and a simple formulation has been developed that permits optimization of the capacitor sizes to meet a constraint such as a total capacitance or total energy storage limit, and also permits optimizing switch sizes subject to constraints on total switch conductances or total switch volt-ampere (V-A) products.
Abstract: Analysis methods are developed that fully determine a switched-capacitor (SC) DC-DC converter's steady-state performance through evaluation of its output impedance. The simple formulation developed permits optimization of the capacitor sizes to meet a constraint such as a total capacitance or total energy storage limit, and also permits optimization of the switch sizes subject to constraints on total switch conductances or total switch volt-ampere (V-A) products. These optimizations then permit comparison among the switched-capacitor topologies, and comparisons of SC converters with conventional magnetic-based DC-DC converter circuits, in the context of various application settings. Significantly, the performance (based on conduction loss) of a ladder-type converter is found to be superior to that of a conventional boost converter for medium to high conversion ratios
456 citations
18 Jun 1995
TL;DR: In this paper, the theoretical performance limits of two-phase switched-capacitor (SC) DC-DC power converters are discussed and the complete set of attainable DC conversion ratios is found.
Abstract: The theoretical performance limits of two-phase switched-capacitor (SC) DC-DC power converters are discussed in this paper. For a given number of capacitors k, the complete set of attainable DC conversion ratios is found. The maximum step-up or step-down ratio is given by the k/sup th/ Fibonacci number, while the bound on the number of switches required in any SC circuit is 3k-2. Practical implications, illustrated by several SC power converter examples, include savings in the number of components required for a given application, and the ability to construct SC power converters that can maintain the output voltage regulation and high conversion efficiency over a wide range of input voltage variations. Limits found for the output resistance and efficiency can be used for selection and comparison of SC power converters. >
426 citations
TL;DR: This paper presents a complete set of blocks implemented in the popular MATLAB SIMULINK environment, which allows designers to perform time-domain behavioral simulations of switched-capacitor sigma-delta (/spl Sigma//spl Delta/) modulators.
Abstract: This paper presents a complete set of blocks implemented in the popular MATLAB SIMULINK environment, which allows designers to perform time-domain behavioral simulations of switched-capacitor (SC) sigma-delta (/spl Sigma//spl Delta/) modulators. The proposed set of blocks takes into account most of the SC /spl Sigma//spl Delta/ modulator nonidealities, such as sampling jitter, kT/C noise, and operational amplifier parameters (white noise, finite DC gain, finite bandwidth, slew rate and saturation voltages). For each block, a description of the considered effect as well as all of the implementative details are provided. The proposed simulation environment is validated by comparing the simulated behavior with the experimental results obtained from two actual circuits, namely a second-order low-pass and a sixth-order bandpass SC /spl Sigma//spl Delta/ modulator.
413 citations
TL;DR: Circuit design methods are proposed to enable simplified gate drivers while supporting multiple topologies (and hence output voltages) and verified by a proof-of-concept converter prototype implemented in 0.374 mm2 of a 32 nm SOI process.
Abstract: This paper describes design techniques to maximize the efficiency and power density of fully integrated switched-capacitor (SC) DC-DC converters. Circuit design methods are proposed to enable simplified gate drivers while supporting multiple topologies (and hence output voltages). These methods are verified by a proof-of-concept converter prototype implemented in 0.374 mm2 of a 32 nm SOI process. The 32-phase interleaved converter can be configured into three topologies to support output voltages of 0.5 V-1.2 V from a 2 V input supply, and achieves 79.76% efficiency at an output power density of 0.86 W/mm2 .
407 citations