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  • A study on multi-level PWM and asynchronous Sigma Delta modulations for enhanced bandlimited signal tracking in switching power amplifiers

     Garcia Tormo, Albert; Poveda Lopez, Alberto; Alarcon Gallo, Eduardo; Guinjoan Gispert, Francisco
    IEEE transactions on circuits and systems I: regular papers
    Date of publication: 2013-06
    Journal article

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    This work deals with multi-level switching amplifiers, in the context of high-efficiency power amplification for signal tracking applications. In particular, this paper evaluates the reduction in the error signal's power due to multi-level power amplification (compared to conventional two-level amplifiers) and compares the performance of two multi-level pulse modulations: PWM and Asynchronous Modulation. First the intrinsic bandwidth limits of multi-level switching amplifiers are inferred, to clearly state the advantages and limitations of multi-level power amplification. From the existing analyses of Pulse Width Modulation already reported in the literature, PWM is herein extended to multiple levels based on an equivalent representation, which allows to derive a closed expression for the power spectrum of multi-level PWM in bandlimited signal tracking. The Asynchronous Modulation is extended to multiple levels and the resulting multi-level encoding algorithm is analyzed in both time and frequency domains. The performance of both modulations is characterized and compared at different operating frequencies and using different number of levels. The main outcomes of this in-depth characterization show that, if the switching frequency is high enough, the tracking error is independent of the modulation and the switching frequency, i.e., it only depends upon the number of levels, which points out the suitability of asynchronous modulations for relatively low switching frequencies (compared to the number of levels).

    This work deals with multi-level switching amplifiers, in the context of high-efficiency power amplification for signal tracking applications. In particular, this paper evaluates the reduction in the error signal's power due to multi-level power amplification (compared to conventional two-level amplifiers) and compares the performance of two multi-level pulse modulations: PWM and Asynchronous ${{Sigma}} {{Delta}}$ Modulation. First the intrinsic bandwidth limits of multi-level switching amplifiers are inferred, to clearly state the advantages and limitations of multi-level power amplification. From the existing analyses of Pulse Width Modulation already reported in the literature, PWM is herein extended to multiple levels based on an equivalent representation, which allows to derive a closed expression for the power spectrum of multi-level PWM in bandlimited signal tracking. The Asynchronous ${{Sigma}} {{Delta}}$ Modulation is extended to multiple levels and the resulting multi-level encoding algorithm is analyzed in both time and frequency domains. The performance of both modulations is characterized and compared at different operating frequencies and using different number of levels. The main outcomes of this in-depth characterization show that, if the switching frequency is high enough, the tracking error is independent of the modulation and the switching frequency, i.e., it only depends upon the number of levels, which points out the suitability of asynchronous modulations for relatively low switching frequencies (compared to the number of levels).

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    Output-capacitorless CMOS LDO regulator based on high slew-rate current-mode transconductance amplifier  Open access

     Saberkari, Alireza; Fathipour, Rasoul; Martínez García, Herminio; Poveda Lopez, Alberto; Alarcon Cot, Eduardo Jose
    IEEE International Symposium on Circuits and Systems
    Presentation's date: 2013-05-21
    Presentation of work at congresses

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    A low quiescent current output-capacitorless CMOS LDO regulator based on a high slew-rate current-mode transconductance amplifier (CTA) as an error amplifier is presented. Load transient characteristic of the proposed LDO is improved even at low quiescent currents, by using a local common-mode feedback (LCMFB) in the proposed CTA. This provides an increase in the order of transfer characteristic of the circuit, thereby enhancing the slew-rate at the gate of pass transistor. The proposed CTA-based LDO topology has been designed and post-layout simulated in HSPICE, in a 0.18 µm CMOS process to supply a load current between 0-100 mA. Postlayout simulation results reveal that the proposed LDO is stable without any internal compensation strategy and with on-chip output capacitor or lumped parasitic capacitances at the output node between 10-100 pF.

    A low quiescent current output-capacitorless CMOS LDO regulator based on a high slew-rate current-mode transconductance amplifier (CTA) as an error amplifier is presented. Load transient characteristic of the proposed LDO is improved even at low quiescent currents, by using a local common-mode feedback (LCMFB) in the proposed CTA. This provides an increase in the order of transfer characteristic of the circuit, thereby enhancing the slew-rate at the gate of pass transistor. The proposed CTA-based LDO topology has been designed and post-layout simulated in HSPICE, in a 0.18 μm CMOS process to supply a load current between 0-100 mA. Postlayout simulation results reveal that the proposed LDO is stable without any internal compensation strategy and with on-chip output capacitor or lumped parasitic capacitances at the output node between 10-100 pF.

  • Chaotic behaviour in on-chip automatic tuning loops for continuous-time filters

     Martínez García, Herminio; El Aroudi, Abdelali; Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    Presentation's date: 2013-07-11
    Presentation of work at congresses

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    Continuous-time filters (CTF) with automatic tuning loops are nonlinear feedback systems with potential instability. While an appropriate small signal linear dynamic modeling of the tunable filter should be obtained for design purpose, its ability to predict the real nonlinear dynamic behavior of the system is limited. In order to overcome this problem, a general and systematic procedure is used to obtain a large signal nonlinear model. The obtained model can accurately predict nonlinear phenomena such as bifurcations and chaotic behavior. From this model, some numerical simulations results are presented in this paper. As far as the authors know, the observation of these phenomena in CTF with tuning loops has not been previously presented. Thus, the results obtained in this work can provide some help to obtain improved controllers (with higher bandwidth and better performance) for the two involved control loops.

  • SiC Power JFET Electrothermal Macromodel

     Massana, Francisco; Chavarria Roe, Javier; Biel Sole, Domingo; Poveda Lopez, Alberto; Guinjoan Gispert, Francisco
    International Conference Mixed Design of Integrated Circuits and Systems
    Presentation's date: 2013-06-21
    Presentation of work at congresses

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    Chaos controller for switching regulators aiming enhanced design-space towards miniaturization  Open access

     Rodríguez Rodríguez, Enric; El Aroudi, Abdelali; Martínez García, Herminio; Poveda Lopez, Alberto; Iu, H.; Alarcon Cot, Eduardo Jose
    International Symposium on Nonlinear Theory and its Applications
    Presentation's date: 2012-10-25
    Presentation of work at congresses

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    This paper tackles the control of fast-scale instabilities in a buck switching power converter aiming to expand its design-space towards miniaturization. After briefly revisiting the working principle of existing chaos controllers, the paper explores an alternative approach based on amplifying the harmonic at the switching frequency. Numerical simulations show that the proposed controller can concurrently improve both fast-scale and slow-scale stability margins. Finally, the paper proposes a chaos controller combined with an output ripple reduction network and studies their interaction with the aim of achieving both low-ripple and improved stability.

  • Electronically tunable switch-mode high-efficiency adaptive band-pass filters for energy harvesting applications

     Gómez Cid-Fuentes, Raül; Martínez García, Herminio; Poveda Lopez, Alberto; Alarcon Cot, Eduardo Jose
    IEEE International Symposium on Circuits and Systems
    Presentation's date: 2012-05-21
    Presentation of work at congresses

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  • Ripple-based prediction of fast-scale instabilities in current mode controlled switching converters

     Rodríguez Rodríguez, Enric; Martínez García, Herminio; Guinjoan Gispert, Francisco; El Aroudi, Abdelali; Poveda Lopez, Alberto; Alarcon Cot, Eduardo Jose
    IEEE International Symposium on Circuits and Systems
    Presentation's date: 2012-05-22
    Presentation of work at congresses

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  • A design-oriented optimization framework for envelope trackers: Application to a sliding-mode control buck converter for EDGE

     Marco Platón, Lázaro; Poveda Lopez, Alberto; Guinjoan Gispert, Francisco; Maksimovic, Dragan; Alarcon Cot, Eduardo Jose
    International Power Electronics and Motion Control Conference
    Presentation's date: 2012-09
    Presentation of work at congresses

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  • A grounded-output 5-switch bipolar buck-boost converter topology for switching power amplifiers

     Garcia Tormo, Albert; Poveda Lopez, Alberto; Alarcon Cot, Eduardo Jose; Guinjoan Gispert, Francisco
    IEEE International Symposium on Circuits and Systems
    Presentation's date: 2011
    Presentation of work at congresses

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    This work presents a switching converter topology which can boost and step down the supply voltage and can deliver both positive and negative voltages to a grounded load (bipolar converter topology with non-floating output). This topology, which uses five switches to perform the power conversion, is mostly intended for switching amplifiers, especially for applications which require both boosting and inverting the supply voltage (to supply bipolar voltage signals), and/or EMI-sensitive applications. Using a single-stage switching amplifier based on this 5-switch topology, it is feasible to supply a grounded load with a symmetrical bipolar voltage signal whose magnitude extends up to several times the magnitude of the supply voltage.

  • Continuous-time CMOS adaptive asynchronous sigma-delta modulator approximating low-fs low-inband-error on-chip wideband power amplifier

     Alarcon Cot, Eduardo Jose; Fernández, Diego; Garcia Tormo, Albert; Madrenas Boadas, Jordi; Poveda Lopez, Alberto
    IEEE International Symposium on Circuits and Systems
    Presentation's date: 2011-05-15
    Presentation of work at congresses

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    A mixed-signal continuous-time-processing standard CMOS implementation of an asynchronous sigma-delta modulator aimed to drive a switching amplifier operating as an on-chip wideband adaptive power supply is presented in this work. The paper first briefly discusses the fundamental limit tracking capabilities of a two-level switching signal to inband-error-free track a bandlimited signal with minimum average switching frequency. It is argued the adequacy of an adaptive asynchronous sigma-delta modulator (AAΣΔ) to approximate such fundamental characteristics. The second part of the paper presents mixed-signal design details of the various subcircuits implementing a CMOS low-power digitally-programmable AAΣΔ modulator, with 7 MHz average switching frequency operation and 1000 µm × 640 µm area occupancy.

  • Bandwidth extension techniques for high-efficiency power amplifiers  Open access

     Garcia Tormo, Albert
    Defense's date: 2011-04-14
    Department of Electronic Engineering, Universitat Politècnica de Catalunya
    Theses

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    Aquesta tesi tracta sobre amplificació de potència d'alt rendiment de senyals variables en el temps; concretament, tracta sobre conversió de potència eficient (amb mínimes pèrdues) de tensions DC continues en senyals de tensió no constants. Aquest tipus de conversió de potència està present en la majoria de dispositius electrònics d'ús quotidià, com ara telèfons mòbils i reproductors de música portàtils, així com també en dispositius d'alta potència com amplificadors d'àudio i estacions base de telefonia mòbil. Generalment l'energia està disponible en forma de tensió DC contínua (d'una bateria o d'una font d'alimentació). D'acord amb la informació a transmetre, aquesta energia s'ha de processar o transformar en un senyal variable en el temps de manera que, per exemple, es pugui convertir en àudio per un altaveu . La tendència de mercat és a reduir la mida i el pes dels dispositius electrònics i a oferir noves funcionalitats, incloent una llarga autonomia en dispositius alimentats per bateries. Millorar l'eficiència dels amplificadors de potència no només n'estendria l'autonomia, sinó que també permetria utilitzar dissipadors més petits i lleugers. Altres aplicacions com les d'alta potència o integrades també es beneficiarien de millores en l'eficiència dels amplificadors de potència. Els dispositius electrònics de processament de potència més eficients són els amplificadors commutats. Aquests utilitzen components reactius (bàsicament bobines i condensadors) per dur a terme un processament de potència idealment sense pèrdues, així com dispositius actius (transistors) controlats com interruptors (o bé tancats o bé oberts), per tal de controlar aquest procés. Tot i que es poden assolir eficiències molt altes amb amplificadors commutats, la precisió de seguiment pot no ser gaire bona. Es pot millorar la precisió de seguiment senzillament incrementant la freqüència de commutació (la freqüència a la qual es fan commutar els interruptors), tot i que, com que es requereix una certa quantitat d'energia per fer commutar cada interruptor (pèrdues de commutació), aquesta tècnica també deteriora l'eficiència de l'amplificador. Existeix doncs un comprimís entre la freqüència de commutació i la precisió de seguiment en els amplificadors commutats (compromís eficiència-distorsió). Els amplificadors commutats habitualment es dissenyen per treballar a una freqüència de commutació alta comparada amb l'amplada de banda que han de seguir. Mentre que amb aquesta estratègia de disseny (i tecnologia actual) es poden dissenyar amplificadors per seguir senyals de l'ordre de kHz, si s'aplica per seguir senyals de l'ordre de MHz, els amplificadors haurien de treballar a freqüències de commutació massa altes, inviables des del punt de vista de les pèrdues de commutació. Amb l'objectiu d'abordar el compromís entre distorsió i eficiència dels amplificadors commutats, aquesta tesi explora diferents tècniques per estendre l'amplada de banda relativa dels amplificadors commutats, és a dir, tècniques per reduir la relació entre la freqüència de commutació de l'amplificador i la seva amplada de banda de seguiment. Basant-se en una interpretació alternativa dels amplificadors commutats, com a procés de codificació i reconstrucció, les diferents tècniques d'extensió de banda que aquí s'exploren contemplen utilitzar modulacions alternatives, amplificació de potència multi-nivell, filtrat d'ordre elevat i polítiques de commutació millorades en els convertidors commutats. La caracterització de les prestacions en termes de freqüència de commutació, error de seguiment i robustesa davant no idealitats (incloent compatibilitat electromagnètica i acoblament entre canals) apunta la idoneïtat de l'amplificació de potència multi-nivell basada en moduladors asíncrons per dissenys que treballin a freqüències de commutació relativament baixes, és a dir, a freqüències de commutació comparables a l'amplada de banda del senyal a seguir i amplificar.

    This thesis is about power amplification of time-varying signals; more precisely, it is about efficient power conversion, i.e. with minimum losses, of DC constant voltages into non-constant voltage signals. This kind of power conversion is quite common in power-management circuits and electronics in general. It is present in most everyday use electronic devices, including mobile phones, portable audio players and routers, as well as in high-power devices such as audio amplifiers and wireless base stations. In most electronic devices, whether portable or not, the energy is available as DC constant voltage (typically from a battery or a power supply). According to the information to transmit, this energy must be processed or transformed into a time-varying analogue signal so that, for instance, it can be directly converted into audio by a speaker or radiated by an antenna. The market trend is to reduce the size and weight of electronic devices whilst offering new or enhanced functionalities, including long autonomy in battery-powered devices (mainly portable). Improving the efficiency of power amplifiers not only extends the autonomy, but also allows using smaller and lighter heatsinks. Other applications such as high-power or embedded would also benefit from efficiency improvements of switching amplifiers. The most efficient power-processing electronic devices are switching amplifiers. Switching amplifiers use reactive components (mainly inductors and capacitors) to perform an ideally lossless power processing, and active devices (transistors) driven as switches, either ON or OFF, to control this process. Whilst very high efficiencies can be achieved with switching amplifiers, their tracking fidelity may not be very high. The tracking fidelity can be improved by simply increasing the switching frequency (i.e. the frequency at which the active devices are driven), although, provided that a certain amount of energy is required to switch the state of each active device (switching losses), this technique also degrades the efficiency of the amplifiers. Therefore, there exists a trade-off between switching frequency and tracking fidelity in switching amplifiers (efficiency-distortion trade-off). Switching amplifiers are typically designed using a high switching frequency compared to the amplifier's tracking bandwidth. Whilst this design strategy leads to feasible designs for kHz-bandwidth applications (using state-of-the-art technology), when applied to MHz-bandwidth applications, it leads to designs operating at very high switching frequencies, unfeasible with regard to switching losses. With the scope of addressing the efficiency-distortion trade-off of switching amplifiers, this thesis explores different techniques to extend the relative bandwidth of switching amplifiers, i.e. techniques to reduce the ratio of the amplifier's switching frequency to the amplifier's tracking bandwidth. Based on an alternative interpretation of switching amplifiers, as an encoding-reconstruction process, the different bandwidth extension techniques consider using alternative modulations, multi-level power amplification, high-order filtering and enhanced switching policies in the switching converter. The performance characterisations in terms of switching frequency, tracking error and robustness against non-idealities (including electromagnetic compatibility and crosstalk) points out the suitability of multi-level power amplification based on asynchronous modulators for designs operating at relatively low switching frequencies, i.e. at switching frequencies in the same range than the bandwidth of the signal to track and power amplify.

  • Circuitos de gestión de energia adaptativos y miniaturizados para recolectores de energía en redes de sensores inalámbricos (WSN)

     Alarcon Cot, Eduardo Jose; Vidal Lopez, Eva Maria; Conesa Roca, Alfons; Poveda Lopez, Alberto; Roman Lumbreras, Manuel; Martínez García, Herminio
    Participation in a competitive project

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  • Fundamental modulation limits for minimum switching frequency inband-error-free high-efficiency power amplifiers

     Garcia Tormo, Albert; Poveda Lopez, Alberto; Alarcon Cot, Eduardo Jose; Guinjoan Gispert, Francisco
    IEEE transactions on circuits and systems I: regular papers
    Date of publication: 2011
    Journal article

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    Current-Steering Switching Policy for a SIDO Linear-Assisted Hysteretic DC/DC Converter  Open access

     Martínez García, Herminio; Silva-Martínez, José; Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    Presentation's date: 2010-07-09
    Presentation of work at congresses

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    This paper proposes the use of linear-assisted switching power converters in the context of single-inductor dual-output (SIDO) applications. By combining a DC/DC ripplecontrolled switching power converter with the respective voltage linear regulators at each output, improved performance in terms of load and line regulations is obtained. To achieve that aim, a current-steering switching policy is proposed, together with a resource-aware circuit implementation. The ripple-based hysteretic control results in variable switching frequency to guarantee critical conduction mode (boundary of CCM and DCM).

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    Bandwidth-Enhancement gm-C Filter with independent ¿o and Q Tuning Mechanisms in Both Topology and Control Loops  Open access

     Martínez García, Herminio; Vidal Lopez, Eva Maria; Cantó, Andrea; Poveda Lopez, Alberto; Guinjoan Gispert, Francisco
    IEEE International Symposium on Circuits and Systems
    Presentation's date: 2010-05-30
    Presentation of work at congresses

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    This paper deals with the proposal of a new topology for a gm-C continuous time filter which allows the adjustment and tuning of its characteristic parameters (ωO and Q) in an independent way (without cross-tuning), thereby extending the Q range of the filter for a particular ωO value. Additionally a comparison of three different Q-tuning algorithms is presented. It is shown that an LMS-based Q-control strategy allows to overcome the intrinsic dependence between the Q and ωO tuning loops. The combination of both the proposed filter topology and the selected control loop algorithms results in an enhanced transient performance as well as an improvement in terms of cross-detuning.

  • Multi-level asynchronous Sigma Delta modulators for wideband switching power amplifiers

     Garcia Tormo, Albert; Poveda Lopez, Alberto; Alarcon Cot, Eduardo Jose; Guinjoan Gispert, Francisco
    IEEE Workshop on Computers in Power Electronics
    Presentation of work at congresses

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    This work extends the Asynchronous ΣΔ Modulator and its Adaptive version to multi-level modulators, targeting wideband high-efficiency switching power amplifiers. The performance of these modulators is compared with the multi-level Pulse Width Modulator, the most common modulator in multilevel switching power amplifiers. Behavioural model simulation results show that, unlike the multi-level PWM (which can only be used at high switching frequencies), the Asynchronous ΣΔ Modulators can also be used at average switching frequencies close to the signal bandwidth. At high switching frequencies, the performance of all the modulators is similar. The Asynchronous ΣΔ Modulators have further and more important advantages, such as high PSRR (even at the input signal frequency), the ability of handling non-regular distributed voltage levels, or a low ratio between the average switching frequency and the maximum instantaneous switching frequency.

  • Takagi-sugeno fuzzy model to approximate mosfet capacitance for VRM applications

     López, Toni; Alarcon Cot, Eduardo Jose; Guinjoan Gispert, Francisco; Poveda Lopez, Alberto
    IEEE International Symposium on Circuits and Systems
    Presentation of work at congresses

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    An enhanced switching policy for buck-derived multi-level switching power amplifiers  Open access

     Garcia Tormo, Albert; Poveda Lopez, Alberto; Alarcon Cot, Eduardo Jose; Bergveld, Henk Jan; Buter, Berry; Karadi, Ravi
    IEEE International Symposium on Circuits and Systems
    Presentation's date: 2010
    Presentation of work at congresses

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    This work proposes a switching policy for multi-level fullbridge switching power converters and analyses their performance by driving them with a multi-level PWM modulation, targeting highefficiency power amplifiers. Unlike conventional policies, which generate the output voltage levels only from the values of the supply voltages, this enhanced policy also uses the values of the voltage difference between supply voltages to generate additional output voltage levels, therefore maximising the number of output voltage levels for a given set of supply voltages and connection switches. Simulation results show that, when tracking a band-limited signal, the proposed switching policy can reduce the power of the high-frequency spectral content from 21% to 11% by upgrading a 5-level amplifier to a 7-level amplifier without adding supply voltages or connection switches.

  • Bandwidth-enhancement g(m)-C filter with independent omega(O) and Q tuning mechanisms in both topology and control loops

     Martínez García, Herminio; Vidal Lopez, Eva Maria; Cantó, Andrea; Poveda Lopez, Alberto; Guinjoan Gispert, Francisco
    IEEE International Symposium on Circuits and Systems
    Presentation's date: 2010
    Presentation of work at congresses

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    This paper deals with the proposal of a new topology for a gm-C continuous time filter which allows the adjustment and tuning of its characteristic parameters (ωO and Q) in an independent way (without cross-tuning), thereby extending the Q range of the filter for a particular ωO value. Additionally a comparison of three different Q-tuning algorithms is presented. It is shown that an LMS-based Q-control strategy allows to overcome the intrinsic dependence between the Q and ωO tuning oops. The combination of both the proposed filter topology and the selected control loop algorithms results in an enhanced ransient performance as well as an improvement in terms of cross-detuning.

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    Single-Input Dual-Output (SIDO) Linear¿Assisted DC/DC Converter  Open access

     Martínez García, Herminio; Silva-Martínez, José; Conesa Roca, Alfons; Poveda Lopez, Alberto
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    Presentation's date: 2009-07-01
    Presentation of work at congresses

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    This article describes a single-input dual output(SIDO) linear-assisted DC/DC converter. Linear-assisted DC/DC converters are structures that allow to take advantages of the two classic alternatives in the design of power supply systems: voltage linear regulators and switching DC/DC converters. Thanks to the combination of a switching converter and two voltage linear regulators, the proposed SIDO converter provides two independent outputs with suitable load and line regulations. In the presented topology the SIDO linear-assisted DC/DC converter operates at the boundary of continuous conduction mode(CCM) and discontinuous conduction mode (DCM) with variable switching frequency.

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    Filtro Gm-C Para Aplicaciones de Comunicaciones con Sintonía Adaptativa del Factor de Calidad Q Independiente de la Sintonía de la Frecuencia Central  Open access

     Vidal Lopez, Eva Maria; Cantó, A.; Martínez García, Herminio; Poveda Lopez, Alberto
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    Presentation's date: 2009-07-01
    Presentation of work at congresses

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    Este artículo muestra la propuesta de un filtro gm-C de segundo orden con control independiente total de la frecuencia central y el factor de calidad diseñado para aplicaciones inalámbricas multiestándar. Se presenta asimismo el diseño de los lazos de control adecuados para hacer la correcta sintonía del filtro tras una breve descripción de las ventajas e inconvenientes de las propuestas encontradas en la bibliografía. El trabajo se completa con una propuesta de mejora del lazo de control del factor de calidad que permite aumentar la rapidez del lazo y disminuir el error de rizado de la señal de control.

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    Filtro gm-C para aplicaciones de comunicaciones con sintonía adaptativa del factor de calidad Q independiente de la sintonía de la frecuencia central  Open access

     Vidal Lopez, Eva Maria; Martínez García, Herminio; Poveda Lopez, Alberto
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    Presentation's date: 2009-07-01
    Presentation of work at congresses

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    Este artículo muestra la propuesta de un filtro gm-C de segundo orden con control independiente total de la frecuencia central y el factor de calidad diseñado para aplicaciones inalámbricas multiestándar. Se presenta asimismo el diseño de los lazos de control adecuados para hacer la correcta sintonía del filtro tras una breve descripción de las ventajas e inconvenientes de las propuestas encontradas en la bibliografía. El trabajo se completa con una propuesta de mejora del lazo de control del factor de calidad que permite aumentar la rapidez del lazo y disminuir el error de rizado de la señal de control.

  • Dynamic modeling of tunable analog integrated filters for a stability study of on-chip automatic tuning loops

     Martínez García, Herminio; Vidal Lopez, Eva Maria; Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto
    Analog integrated circuits and signal processing
    Date of publication: 2009-12
    Journal article

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  • Advanced Wide Band Gap Semiconductor Devices for Rational Use of Energy (RUE)

     Alarcon Cot, Eduardo Jose; Fernandez Martinez, Daniel; Biel Sole, Domingo; Guinjoan Gispert, Francisco; Garcia Tormo, Albert; Masana Nadal, Francisco; Poveda Lopez, Alberto
    Participation in a competitive project

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  • Characterizing fast-scale instability in a buck-based switching amplifier for wideband tracking

     Rodriguez Vilamitjana, Enric; Guinjoan Gispert, Francisco; Poveda Lopez, Alberto; Alarcon Cot, Eduardo Jose; El-Aroudi, A
    IEEE International Symposium on Circuits and Systems
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  • On-chip wideband adaptive energy management of RF power amplifiers: towards efficient next-generation mobile communications RF transmitters

     Martínez García, Herminio; Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto; Vidal Lopez, Eva Maria; Pol Fernandez, Clemente
    Participation in a competitive project

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  • Characterisation of Low-OSR Asynchronous Sigma-Delta Modulator with High-Order Buck Converter for Wideband Switching Amplifier

     Garcia-Tormo, Albert; Garcia Tormo, Albert; Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto; Guinjoan Gispert, Francisco
    IEEE International Symposium on Circuits and Systems
    Presentation of work at congresses

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  • Automatic dead-time adjustment CMOS mixed-signal circuit for a DCM-operated 3-level switching power converter

     Villar Pique, Gerard; Alarcon Cot, Eduardo Jose; Guinjoan Gispert, Francisco; Poveda Lopez, Alberto
    IEEE International Symposium on Circuits and Systems
    Presentation of work at congresses

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  • General-purpose ripple-based fast-scale instability prediction in switching power regulators

     Rodriguez, E; Villar Pique, Gerard; Guinjoan Gispert, Francisco; Poveda Lopez, Alberto; El-Aroudi, A; Alarcon Cot, Eduardo Jose
    IEEE International Symposium on Circuits and Systems
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  • Ripple-based Period-2 bifurcation border detection

     Rodríguez-Vilamitjana, E; Poveda Lopez, Alberto; El-Aroudi, A; Alarcon Cot, Eduardo Jose
    European Conference on Circuit Theory and Design
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  • Derivation of the sliding domain for a buck-based switching amplifier in wideband signal tracking applications

     Marco Platón, Lázaro; Rodríguez, Enric; Gerard, Villar; Poveda Lopez, Alberto; Alarcon Cot, Eduardo Jose
    European Conference on Circuit Theory and Design
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  • Sistema de adquisición de banda ancha para prácticas remotas con convertidores conmutados DC-DC

     Garcia Tormo, Albert; Poveda Lopez, Alberto; Guinjoan Gispert, Francisco; Prat Viñas, Luis
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
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  • Límites de ancho de banda en amplificadores PWM

     Marco Platón, Lázaro; Rodríguez, E; Poveda Lopez, Alberto; Alarcon Cot, Eduardo Jose; Maksimovic, D
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
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  • Novel approcah for avoiding bifurcations in switching dc-dc converters : a ripple-based unified index

     Aroudi, El; Alarcon Cot, Eduardo Jose; Martínez-Artega, J; Villar Pique, Gerard; Guinjoan Gispert, Francisco; Poveda Lopez, Alberto
    IFAC Conference on Analysis and Control of Chaotic Systems
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  • Improving the Stability of On-Chip Automatic Tuning Loops for Continuous?Time Filters

     Martínez García, Herminio; Vidal Lopez, Eva Maria; Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto
    IEEE International Symposium on Circuits and Systems
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  • Predicting fast-scale instabilities in switching power converters: a ripple-based unified perspective

     Alarcon Cot, Eduardo Jose; El-Aroudi, A; Martínez, J Artega; Villar Pique, Gerard; Guinjoan Gispert, Francisco; Poveda Lopez, Alberto
    IEEE International Symposium on Circuits and Systems
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  • Access to the full text
    Diseño e implementación de un convertidor DC/DC híbrido  Open access

     Martínez García, Herminio; Conesa Roca, Alfons; Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    Presentation's date: 2006-09-13
    Presentation of work at congresses

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    El presente artículo muestra el diseño y realización práctica de una topología mixta o híbrida lineal–conmutada para convertidores de potencia DC/DC, formada por un regulador lineal de tensión y un convertidor conmutado DC/DC. El regulador lineal serie tiene como objetivo el cancelar los rizados de salida y proporcionar respuestas rápidas frente a variaciones de carga, mientras que el regulador conmutado, en paralelo con el lineal, permite proporcionar a la carga prácticamente la totalidad de la corriente demandada por la misma. La finalidad de la topología es la de obtener altos rendimientos, propios de los convertidores conmutados DC/DC, pero aprovechando las convenientes características de regulación que poseen los reguladores lineales serie de tensión. En el presente artículo se detalla el proceso de diseño e implementación de un convertidor híbrido de 80 W que permite alimentar cargas con tensiones de salida fácilmente ajustables. El diseño implementado ha permitido obtener corrientes de salida de hasta 8 A para tensiones de salida de hasta 10 V, con excelentes regulaciones tanto de línea como de cargas.

  • Access to the full text
    Aspectos comparativos en las estrategias de control de convertidores DC/DC híbridos  Open access

     Martínez García, Herminio; Conesa Roca, Alfons; Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    Presentation's date: 2006-09-13
    Presentation of work at congresses

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    Dentro de los convertidores DC/DC híbridos, formados por un regulador lineal en paralelo con un convertidor conmutado, existen diferentes estrategias de control que permiten fijar la frecuencia de conmutación en función de alguna característica del regulador lineal. El presente artículo compara dos estrategias de control que, aunque pueden aplicarse a la misma estructura circuital de convertidor híbrido, son sensiblemente diferentes. La primera de ella, presentada en [1], considera como bloque principal al convertidor conmutado y, al regulador lineal, como módulo auxiliar. Por su parte, la propuesta realizada por los autores del presente artículo considera como conjunto principal al lineal y al conmutado como módulo auxiliar.

  • Badwidth limits inpwm switching amplifiers

     Marco, L; Poveda Lopez, Alberto; Alarcon Cot, Eduardo Jose; Maksimovic, E Alarcón I D
    IEEE International Symposium on Circuits and Systems
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  • RIPPLE BASED INDEX FOR PREDICTING FAST-SCALE INSTABILITY OF DC-DC CONVERTERS IN CCM AND DCM. Invited paper in special session "Bifurcation and Chaos in Power Electronics"

     Rodriguez, E; Aroudi, A El; Alarcon Cot, Eduardo Jose; Leyva Grasa, Ramon; Villar Pique, Gerard; Guinjoan Gispert, Francisco; Poveda Lopez, Alberto
    ICIT 2006 - IEEE International Conference on Industrial Technology
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  • 'Sliding Mode Control of Switching Converters: General Theory in an Integrated Solution

     Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto
    Hait journal of science and engineering
    Date of publication: 2005-12
    Journal article

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  • Towards an on-chip boost switching power converter: a design space exploration'

     Villar Pique, Gerard; Guinjoan Gispert, Francisco; Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto
    Hait journal of science and engineering
    Date of publication: 2005-12
    Journal article

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  • Quasi-optimum efficiency in output voltage hysteretic control for a buck switching converter with wide load range

     Alarcon Cot, Eduardo Jose; Villar Pique, Gerard; Guinjoan Gispert, Francisco; Poveda Lopez, Alberto
    IEEE POWER ELECTRONICS SPECIALISTS CONFERENCE
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  • Efficiency-oriented switching frequency tunning for a buck switching power converter

     Alarcon Cot, Eduardo Jose; Villar Pique, Gerard; Guinjoan Gispert, Francisco; Poveda Lopez, Alberto
    IEEE International Symposium on Circuits and Systems
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  • Amplificador Híbrido Lineal-Conmutado para Cargas con Amplio Margen Dinámico

     Martínez García, Herminio; Alarcon Cot, Eduardo Jose; Vidal Lopez, Eva Maria; Poveda Lopez, Alberto
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
    Presentation's date: 2005-09-26
    Presentation of work at congresses

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  • Improving the Stability of On-Chip Automatic Tuning Loops For Continuous-Time Filters with an Analog Adaptive Controller

     Martínez García, Herminio; Vidal Lopez, Eva Maria; Alarcon Cot, Eduardo Jose; Poveda Lopez, Alberto
    IEEE International Symposium on Circuits and Systems
    Presentation of work at congresses

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  • Diseño e Implementación de un Current Conveyor CMOS con Amplio Margen Dinámico

     Martínez García, Herminio; Alarcon Cot, Eduardo Jose; Marco, L; Vidal Lopez, Eva Maria; Poveda Lopez, Alberto
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
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  • Amplificador Híbrido Lineal-Conmutado para Cargas con Amplio Margen Dinámico

     Martínez García, Herminio; Alarcon Cot, Eduardo Jose; Marco Platón, Lázaro; Vidal Lopez, Eva Maria; Poveda Lopez, Alberto
    Seminario Anual de Automática, Electrónica Industrial e Instrumentación
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  • Multi-Mode Controller CMOS Integrated Circuit for Switching Power Converters

     Alarcon Cot, Eduardo Jose; Villar Pique, Gerard; Martínez García, Herminio; Vidal Lopez, Eva Maria; Porta, S; Guinjoan Gispert, Francisco; Poveda Lopez, Alberto
    IEEE International Symposium on Circuits and Systems
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