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Resonant and quasi-resonant dc-dc converters have been introduced to increase the operating frequency of switching power converters, with advantages in terms of performance, cost, and/or size. In this paper, we focus on class-E resonant topologies, and we show that about twenty different architectures proposed in the last three decades can be reduced to two basic topologies, allowing the extension to all these resonant converters of an exact and straightforward design procedure that has been recently proposed. This represents an important breakthrough with respect to the state of the art, where class-E circuit analysis is always based on strong simplifying assumptions, and the final circuit design is achieved by means of numerical simulations. The potentialities of the proposed exact methodology are highlighted by realistic circuit-level simulations, where the desired waveforms are obtained in one single step without the need of a time-consuming iterative trial-and-error process. INDEX TERMS Circuit theory, class-E converters, resonant dc-dc converters. I. INTRODUCTION Resonant and quasi-resonant dc-dc converters have been introduced with the aim of reducing switching loss impact at high frequencies. This allows a converter to operate with good efficiency at high frequency ranges (up to the VHF range 30 − 300MHz) thus increasing the system power density [1]-[7]. A higher switching frequency, in fact, paves the way to both size and cost reduction, as well as improved dynamic performance [2]. In this paper we focus on the Class-E converters [2], [5] that are based on the so-called soft switching technique and that are specifically designed to overcome the main drawback of conventional class-D (hard-switching) topologies given by the frequency dependent loss mechanisms. The soft switching technique has been proposed, to the best of authors' knowledge, by Sokal et al. in [1] as a way to improve performance in RF amplifiers [1], [2], [8]. The main concept is the introduction of additional reactive components in order to properly shape voltage and current waveforms. The associate editor coordinating the review of this manuscript and approving it for publication was Derek Abbott.

This paper presents a new approach for the design of a class-E resonant DC-DC converter. The small number of passive components featured by the considered topology allows to exactly solve the differential equations regulating the circuit evolution, and to develop a semi-analytic design procedure based on the differential equations solution. This represents an important breakthrough with respect to the state-of-the-art, where class-E circuit analysis is always based on strong simplifying assumptions, and the exact circuit design is achieved by means of numerical simulations after many time-consuming parametric sweeps

We report a low cost mobile EEG system for characterizing cortical auditory responses. The system is built using commercial off-the-shelf components and each unit costs less than $200. It measures seven EEG channels plus one audio channel (envelope only), and communicates the data to external devices via Bluetooth. A novel implementation was pursued in order to support local signal compression using compressed sensing. At the same time, it provides a low cost solution that is useful for recording cortical auditory responses and extracting clinically relevant features of the waveform. This system has been designed with the eventual goal of long term monitoring of the brain activity of schizophrenic patients outside a clinical setting, in order to better understand auditory hallucinations and manage their ongoing treatment. In this preliminary study we obtained simultaneous audio and cortical recordings of evoked auditory responses from normal healthy subjects wearing the EEG for several hours in duration. We report evoked auditory responses for 2 Hz and 40 Hz click trains. We also report alpha wave responses, demonstrating stable and high quality recordings over a five hour period

In this paper we take into account the rakeness approach in the design of Compressed Sensing (CS) based system, which allows, by means of the matching of some statistical properties of the CS sampling functions with statistical features of the input signal, to greatly increase system performance in terms of either a reduction of resources (hardware, energy, etc) required for the signal acquisition or an increase in the acquisition quality. In particular, with respect to the general formulation, we make two additional and non-restrictive hypotheses to ensure a good behavior of the system. With these, we can compute an upper and a lower bound for the parameter r used to control the statistical matching level, and we show with some numerical examples that the choice of r is not critical. In particular, any r value taken from the computed interval ensures almost optimal performance, making the rakeness approach robust and worthwhile