Artículos (Ingeniería Electrónica)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/11357

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Variational Autoencoder for the Prediction of Oil Contamination Temporal Evolution in Water Environments
(MDPI, 2025-03) Casado Pérez, Alejandro; Yanes Luis, Samuel; Toral, S. L.; Perales Esteve, Manuel Ángel; Gutiérrez Reina, Daniel; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Junta de Andalucía; European Union (UE); Universidad de Sevilla. TIC201: ACE-TI; Universidad de Sevilla. TEP203: Física Interdisciplinar Fundamentos y Aplicaciones
The water quality monitoring of large water masses using robotic vehicles is a complex task highly developed in recent years. The main approaches utilize adaptative informative path planning of fleets of autonomous surface vehicles and computer learning methods. However, water monitoring is characterized by a highly dynamic and unknown environment. Thus, the characterization of the water quality state of a water mass becomes a challenge. This paper proposes a variational autoencoder structure, trained in a model-free manner, that aims to provide a dynamic contamination model from partial observations of a homogeneous fleet of autonomous surface vehicles. To train the proposed approach, an oil spillage simulator based on heuristics is provided for world building. The proposed variational autoencoder was tested in three different environments characterized by different oil spill movements and twp different fleets equipped with different sensors. The results show accurate future contamination distribution predictions with a mean squared error ranging from 3 to 9% of the baseline at validation, defined as the static approach. Further tests addressed the overfit of the proposed neural network, showing a high robustness against unseen scenarios, and the effects of the gathered monitoring information in the variational autoencoder performance.
Smart Railway Operation Aid System for Facilities With Low-Safety Requirements
(Institute of Electrical and Electronics Engineers (IEEE), 2021) Torralba Silgado, Antonio Jesús; García Castellano, María; Hernández-González, Miguel; García Martín, Juan Pablo; Pérez Mira, Ventura; Gutiérrez Rumbao, Javier; Fernández-Sanzo, Roberto; Jácome-Moreno, Antonio; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Autoridad Portuaria de Sevilla; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla. TIC192: Ingeniería Electrónica
Rail traffic control systems are undergoing an important transformation. ERMTS/ECTS, CBTC, PTC and other train control systems based on radio communication are being deployed in different countries. These systems meet the high safety requirements for passenger traffic, and cover from congested urban areas to high-speed trains. However, there is a set of facilities, such as ports, dry ports, facilities for the repair and maintenance of trains, logistic centers, mines, etc., whose trains, that only carry freight, circulate in a controlled environment at a low speed. These facilities have low safety requirements. For them, present commercial systems become too expensive, so that, in most cases, railway traffic is still handled manually. This paper presents a system to aid in the exploitation of rail traffic for this type of facilities, called SFPS (Seville Ferro-Port System). SFPS presents many of the features of the most advanced traffic control systems, but incorporates innovations based on Information and Communications Technologies to reduce costs. To this end, train location is based on a satellite global positioning system, physical signs are replaced by virtual ones, displayed in an On-Board Unit, and communication is almost entirely wireless. SFPS has been in a trial phase since March 2016, covering part of the railway facilities of the Port Authority of Seville, with satisfactory results.
AISCS: Autonomous, Intelligent Sign Control System using Wireless Communication and LED Signs for Rural and Suburban Roads
(Institute of Electrical and Electronics Engineers (IEEE), 2022-03) Torralba Silgado, Antonio Jesús; García Martín, Juan Pablo; González Romo, Juan Manuel; García Castellano, María; Peral López, José; Pérez Mira, Ventura; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Consejería de Fomento, Infraestructuras y Ordenación del Territorio, Junta de Andalucía; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla. TIC192: Ingeniería Electrónica
The number of road accidents remains too high. Different initiatives are being taken to reduce the total, whether acting on the vehicle, the driver, or the infrastructure. It is well known that most incidents occur in rural and suburban areas, which have light, unattended traffic. This work presents the Autonomous, Intelligent Sign Control System (AISCS), a robust framework based on wireless communication and LED signs. The controlled toggling of the illuminated signs alerts drivers at accident-prone locations. The AISCS architecture is based on video cameras that detect traffic conditions and on sensing units that monitor environmental variables that can impact traffic. These are connected to a local controller with a decision-making logic with two layers of intelligence. The upper layer uses heuristic rules to classify a scene, while the lower layer uses a fuzzy logic controller to act on autonomous LED signs. The results obtained from two demonstrators, which have been in operation for more than two years in rural and suburban areas, respectively, are also shown. AISCS improves traffic safety and smoothness compared to traditional traffic signs, reducing power consumption by more than 90% against an always-on system.
Energy consumption analytical modeling of NB-IoT devices for diverse IoT applications
(Elsevier, 2023-08) García Martín, Juan Pablo; Torralba Silgado, Antonio Jesús; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla. TIC192: Ingeniería Electrónica
Internet of things (IoT) has been employed in recent years across multiple disciplines in the Fifth Generation (5G) era. The low power consumption of the devices allows long battery lifetimes with increasing wireless coverage ranges. This paper presents a comprehensive power consumption model for battery lifetime estimation in narrowband IoT (NB-IoT), which is based on the user equipment (UE) state diagram and considers the extended discontinuous reception (eDRX) and power saving mode (PSM) mechanisms. This model has been used to simulate the effect of varying NB-IoT link parameters, covering a range of values defined in the specification, corresponding to a wide range of applications. Indeed, this study focuses on mathematical analysis of UE power consumption, mainly for NB-IoT communication applications. Repetitions, as defined in the standard, have also been considered in the analysis. Extensive simulations have been carried out to show the power of the proposed model, which provides accurate results for a wide variety of network parameters and let the network designer to select the most appropriated setup. They also show that the value of link parameters must be carefully selected to achieve a battery lifetime of more than a decade with a standard battery of 5 Wh capacity.
Advanced Distributed Control of Parallel Resonant CLLC DAB Converters
(MDPI, 2025) Carmona Vicente, David; Muñoz Carrero, Alba; Galván Díez, Eduardo; Carrasco Solís, Juan Manuel; Rodríguez Rubio, Francisco; Universidad de Sevilla. Departamento de Ingeniería Eléctrica; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Universidad de Sevilla. Departamento de Ingeniería de Sistemas y Automática; Agencia Estatal de Investigación. España; European Union (UE)
The integration of hybrid alternating current (AC) and direct current (DC) networks has gained relevance due to the growing demand for more flexible, efficient, and reliable electrical systems. A key aspect of this integration is the parallelization of power converters, which presents several technical challenges, such as current sharing imbalances, circulating currents, and control complexity. This paper proposes a distributed control architecture for parallel resonant CLLC dual active bridge (DAB) converters to address these issues in hybrid AC–DC networks and microgrids. The approach includes a master voltage controller to regulate the output voltage and distributed local current controllers to ensure load balance. The approach minimizes the difference between the output and input voltages, allowing for independent control of power flow. Simulation and experimental results show significant improvements. The system stability has been demonstrated experimentally. Transient response has been improved with response time 80% lower using the feed-forward term. The system maintained stability with current sharing deviations below 3% under full and low load conditions. Finally, scalability is ensured by the proposed distributed controller because the central power controller is not affected by the number of units in parallel used in the application. This solution is suitable for advanced hybrid networks and microgrid applications.
Application specific integrated circuit solution for multi-input multi-output piecewise-affine functions
(John Wiley and Sons Ltd, 2016-01) Brox Jiménez, María; Martínez Rodríguez, Macarena Cristina; Tena Sánchez, Erica; Baturone Castillo, María Iluminada; Acosta Jiménez, Antonio José; Universidad de Sevilla. Departamento de Electrónica y Electromagnetismo; Universidad de Sevilla. Departamento de Tecnología Electrónica; European Commission (EC); Ministerio de Economía y Competitividad (MINECO). España; Consejo Superior de Investigaciones Científicas (CSIC)
This paper presents a fully digital architecture and its application specific integrated circuit implementation for computing multi-input multi-output (MIMO) piecewise-affine (PWA) functions. The work considers both PWA functions defined over regular hyperrectangular and simplicial partitions of the input domains and also lattice PWA representations. The proposed architecture is able to implement PWA functions following different realization strategies, using a common structure with a minimized number of blocks, thus reducing power consumption and hardware resources. Experimental results obtained with application specific integrated circuit (ASIC) integrated in a 90-nm complementary metal-oxide semiconductor standard technology are provided. The proposed architecture is compared with other digital architectures in the state of the art habitually used to implement model predictive control applications. The proposal is superior in power consumption (saving up to 86%) and economy of hardware resources (saving up to 40% in comparison with a mere replication of the three representations) to other proposals described in literature, being ready to be used in applications where high-performance and minimum unitary cost are required.
Ensemble speed estimation in IFOC with transient detector
(Wiley, 2025) Arahal, Manuel R.; Garrido Satué, Manuel; Martínez Heredia, Juana María; Perales Esteve, Manuel Ángel; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Universidad de Sevilla. Departamento de Ingeniería de Sistemas y Automática; Agencia Estatal de Investigación. España
Rotating electric machines have experienced a vast increase in use in recent times due to the electrification of various segments, including electric vehicles. Different machine types, electronic converters, and control schemes are used. In particular, the combination of indirect field oriented control (IFOC) with incremental encoders is widely utilized. Despite theoretical efforts, practical tuning of IFOC-like structures is not easy due to non-idealities. These arise from difficult to model phenomena appearing in the system. In particular, the latency and phase loss of the speed estimation have a negative effect on performance. This paper proposes the use of an ensemble of speed estimators to reduce these negative effects. In the proposal, ripples and latency of the speed estimations are treated as terms in a tradeoff situation. The proposal allows to obtain low ripple in a steady state combined with low latency during transients.
Concurrent AI Tuning of a Double-Loop Controller for Multi-Phase Drives
(MDPI, 2024) Garrido Satué, Manuel; Barrero, Federico; Martínez Heredia, Juana María; Colodro Ruiz, Francisco; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Universidad de Sevilla. Departamento de Ingeniería de Sistemas y Automática; Agencia Estatal de Investigación. España
The control of electric drives is an important topic due to the wide-spread use of such devices. Among these, multi-phase induction machines are gaining momentum in variable-speed applications. The usual control practice is the use of a speed Proportional–Integral loop that sets the current reference for an inner controller. This inner controller decides the voltage to be applied, which is realized by an electronic power converter. This paper presents an Artificial Intelligence (AI) scheme for tuning. It aims to optimize the usual figures of merit for drives. Moreover, tuning for both loops is tackled concurrently. The adjustment is performed relying on the operating region to address non-linear behavior. The results obtained using a five-phase induction motor illustrate that the proposed method can work in the entire operating range of the drive with improved results.
A Long-Range and Low-Cost Emergency Radio Beacon for Small Drones
(MDPI, 2024) Martínez Heredia, Juana María; Olivera, Jorge; Colodro Ruiz, Francisco; Bravo, Manuel; Arahal, Manuel R.; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Universidad de Sevilla. Departamento de Ingeniería de Sistemas y Automática; Ministerio de Ciencia e Innovación (MICIN). España
The increasing use of unmanned aerial vehicles (UAVs) in the commercial and recreational sectors has led to a heightened demand for effective recovery solutions after a crash, particularly for lightweight drones. This paper presents the development of a long-range and low-cost emergency radio beacon designed specifically for small UAVs. Unlike traditional emergency locator transmitters (ELTs), our proposed beacon addresses the unique needs of UAVs by reducing size, weight, and cost, while maximizing range and power efficiency. The device utilizes a global system for mobile (GSM)-based communication module to transmit location data via short message service (SMS), eliminating the need for specialized receivers and expanding the operational range even in obstaclerich environments. Additionally, a built-in global navigation satellite system (GNSS) receiver provides precise coordinates, activated only upon impact detection through an accelerometer, thereby saving power during normal operations. Experimental tests confirm the extended range, high precision, and compatibility of the prototype with common mobile networks. Cost-effective and easy to use, this beacon improves UAV recovery efforts by providing reliable localization data to users in real time, thus safeguarding the UAV investment.
An Improved Speed Sensing Method for Drive Control
(MDPI, 2025) Arahal, Manuel R.; Garrido Satué, Manuel; Martínez Heredia, Juana María; Colodro Ruiz, Francisco; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Universidad de Sevilla. Departamento de Ingeniería de Sistemas y Automática; Agencia Estatal de Investigación. España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER)
Variable-speed electrical drive control typically relies upon a two-loop scheme, one for torque/speed and another for stator current control. In modern drive control methods, the actual mechanical speed is needed for both loops. In practical applications, the speed is often acquired by incremental rotary encoders. The most used method derives speed from an encoder pulse count during a fixed amount of time. It is known that this sensing method produces time delay in the speed feedback loop as well as fluctuations in the speed measurements. Time lags produce phase loss that has potentially negative effects on the overall drive performance. Nevertheless, the pulse counting method is favored in most cases due to its simplicity and existing support for its use in digital signal processors. In this paper, a new speed sensing method is proposed to reduce time lag without incurring increased fluctuations. The proposal uses a novel transient detector to determine the actual operational regime of the drive: transient or stationary. Transient detection is not based on measured speeds but works directly with the train of incoming encoder pulses. The method is designed to work well with established digital signal processor routines. The proposal is assessed through experimentation on a real five-phase induction motor.
Ionizing radiation damage in 65 nm CMOS technology: influence of geometry, bias and temperature at ultra-high doses
(Elsevier, 2021-01) Borghello, G.; Lerario, E.; Faccio, F.; Koch, H.D.; Termo, G.; Michelis, S.; Márquez Lasso, F.J.; Palomo Pinto, Rogelio; Muñoz Chavero, Fernando; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Universidad de Sevilla. TIC192: Ingeniería Electrónica
We studied the radiation response of 3 different 65 CMOS planar technologies at the ultra-high doses expected to be reached in the HL-LHC, the upgraded large hadron collider of CERN. All the processes studied are sensitive to radiation and show similar degradation mechanisms and, albeit with different intensities, similar dependencies on device geometry, applied polarization and temperature. The results obtained confirmed that the performance of MOS transistors exposed to ultra-high doses is mainly affected by radiation-induced charge trapped in auxiliary oxides such as shallow trench isolation oxides and spacers. The extensive data collected has been used to develop guidelines to qualify to ultra-high doses ASICs designed in the 65 technology node.
High resolution 3D characterization of silicon detectors using a Two Photon Absorption Transient Current Technique
(Elsevier, 2020-04) Fernández García, Marcos; Jaramillo Echeverría, Richard; Moll, Michael; Montero Santos, Raúl; Palomo Pinto, Rogelio; Vila, Iván; Wiehe, Moritz; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Ministerio de Ciencia y Tecnología (MCYT). España; European Union (UE). H2020
The Two Photon Absorption Transient Current Technique (TPA-TCT) is a tool to characterize semiconductor detectors using a spatially confined laser probe. Excess charge carriers are produced by the simultaneous absorption of two sub-bandgap photons in the material. The current induced by the motion of carriers is studied using well known TCT systems. Differently to standard TCT where the energy deposition (pair creation) is continuous along the beam, TPA-TCT reduces this region to an ellipsoidal volume, achieving thus, true 3D spatial resolution. This paper gives an overview of the technique and shows its performance in irradiated detectors, in particular diodes and High Voltage CMOS detectors.
Advanced System-on-Chip Field-Programmable-Gate-Array-Powered Data Acquisition System for Pixel Detectors
(MDPI, 2024) Jiménez Sánchez, Jorge; Blanco-Carmona, Pedro; Hinojo Montero, José María; Palomo Pinto, Rogelio; Millán Vázquez de la Torre, Rafael Luis; Muñoz Chavero, Fernando; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Agencia Estatal de Investigación. España
Particle detector systems require data acquisition systems (DAQs) as their back-end. This paper presents a new edge-computing DAQ that is capable of handling multiple pixel detectors simultaneously and was designed for particle-tracking experiments. The system was designed for the ROC4SENS readout chip, but its control logic can be adapted for other pixel detectors. The DAQ was based on a system-on-chip FPGA (SoC FPGA), which includes an embedded microprocessor running a fully functional Linux system. An application using a client–server architecture was developed to facilitate remote control and data visualization. The comprehensive DAQ is very compact, thus reducing the typical hardware load in particle tracking experiments, especially during the obligatory characterization of particle telescopes.
Development of a tabletop setup for the transient current technique using two photon absorption in silicon particle detectors
(IEEE, 2021-02) Wiehe, Moritz; Fernández García, Marcos; Moll, Michael; Montero, Raúl; Palomo Pinto, Rogelio; Vila, Iván; Universidad de Sevilla. Departamento de Ingeniería Electrónica
The transient current technique (TCT) is widely used in the field of silicon particle detector development. So far, only laser wavelengths with a photon energy larger than or similar to the silicon bandgap (single photon absorption) were used. Recently, measurements using two-photon absorption (TPA) for silicon detector testing have been carried out for the first time. Excess carriers are only created at the focal point of the laser beam and thus resolution in all three spatial directions could be achieved. The resolution perpendicular to the incident laser beam could be increased roughly by a factor of 10. First measurements using this new method were performed at the Singular Laser Facility of Universidad del País Vasco (UPV)/Euskal Herriko Unibertzitatea (EHU). Following the initial success of the method, a compact TPA-TCT setup is under development. A first description of the setup and laser system is presented in this article.
A survey on unmanned aerial and aquatic vehicle multi-hop networks: Wireless communications, evaluation tools and applications
(Elsevier, 2018-04) Sánchez García, Jesús; García-Campos, José Manuel; Arzamendia, Mario; Gutiérrez Reina, Daniel; Toral, S. L.; Gregor, Derlis O.; Universidad de Sevilla. Departamento de Ingeniería Telemática; Universidad de Sevilla. Departamento de Ingeniería Electrónica
Unmanned aerial and aquatic vehicle networks have attracted the attention of the wireless communication research community in the last decade. The low manufacturing costs for developing small unmanned vehicles and the notable developments on wireless communication technologies have made possible the design of cooperative applications involving multiple unmanned aerial and aquatic vehicles. However, the design of wireless networks, which include very dynamic and complex entities like unmanned vehicles, poses many challenges. Fortunately, unmanned aerial vehicle networks applications usually resemble those of unmanned aquatic vehicle networks such as military missions, or environmental monitoring among others. With the exception of the obvious differences in the lower layers of the wireless communications protocols, valid approaches used in the aerial medium could be easily adapted to the aquatic medium. This survey presents together the main features to take into account for designing unmanned aerial and aquatic vehicle networks with the aim to help the reader to transfer valid approaches and techniques between aerial and aquatic applications. We survey the results of more than 100 references on this topic published in international conferences and journals, and we also include the results of several bibliometric analyses in order to better present the status of the art and research directions on this scientific area.
Voronoi Multi-phase Predictive Current Control with Variable Application Times
(IEEE, 2025) Arahal, Manuel R.; Barrero, Federico; Garrido Satué, Manuel; Colodro Ruiz, Francisco; Universidad de Sevilla. Departamento de Ingeniería de Sistemas y Automática; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Agencia Estatal de Investigación. España
Predictive Stator Current Control (PSCC) is a flexible technique for drives of different types. For the multiphase case, PSCC must deal with an increased number of available control options (the voltage vectors) and cope with the different current spaces: torque producing (α−β) and harmonic planes (x − y). In this paper, a Voronoi region based scheme is designed to cope with both issues while maintaining an affordable commutation frequency. The proposal is enhanced by using variable application times with fine resolution. The method is compared with state of the art dead-beat multi-vector approach. The comparison is made using a real, laboratory setup designed for experimentation based on a five-phase induction machine. The comparison shows enhanced control results together with a reduction in harmonic content, without compromising the switching frequency limits of the power converters and maintaining flexibility due to the cost function.
Multi-Phase Stator Current Tracking with Gradual Penalization of Commutations
(MDPI, 2024-07) Arahal, Manuel R.; Garrido Satué, Manuel; Martínez Heredia, Juana María; Universidad de Sevilla. Departamento de Ingeniería de Sistemas y Automática; Universidad de Sevilla. Departamento de Ingeniería Electrónica
Energy efficiency in drives is an important issue. In converter-supplied variable-speed drives, switching losses can amount to a significant portion of all losses. This has been considered in Predictive Stator Current Control (PSCC), considering commutations at the power converter. However, in multi-phase drives, the computational burden limits the application of said techniques. Recent fast predictive algorithms have enabled shorter application times with enhanced tracking results. However, the switching frequency becomes larger with diminishing sampling periods. This paper presents a method that retains the fast computation of recent methods while reducing the switching frequency. The proposal revolves around a modification of the cost function to penalize commutations in a nonlinear way. For this task, a novel, gradual penalization is introduced. The method is experimentally applied to a five-phase induction motor. Experimental results show a significant reduction in switching frequency without compromising other control objectives. This results in an enhanced PSCC with a small sampling period and reduced switching losses.
Assessing SOC Estimations via Reverse-Time Kalman for Small Unmanned Aircraft
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-08) Arahal, Manuel R.; Pérez Vega-Leal, Alfredo; Garrido Satué, Manuel; Esteban Roncero, Sergio; Universidad de Sevilla. Departamento de Ingeniería de Sistemas y Automática; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Agencia Estatal de Investigación. España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER)
This paper presents a method to validate state of charge (SOC) estimations in batteries for their use in remotely manned aerial vehicles (UAVs). The SOC estimation must provide the mission control with a measure of the available range of the aircraft, which is critical for extended missions such as search and rescue operations. However, the uncertainty about the initial state and depth of discharge during the mission makes the estimation challenging. In order to assess the estimation provided to mission control, an a posteriori re-estimation is performed. This allows for the assessment of estimation methods. A reverse-time Kalman estimator is proposed for this task. Accurate SOC estimations are crucial for optimizing the utilization of multiple UAVs in a collaborative manner, ensuring the efficient use of energy resources and maximizing mission success rates. Experimental results for LiFePO4 batteries are provided, showing the capabilities of the proposal for the assessment of online SOC estimators.
Lynx: An Efficient and Flexible Communication Schema for On-Chip and Off-Chip Applications in Distributed Static Industrial Networks
(IEEE, 2024-07-17) Guzmán-Miranda, Hipólito; Márquez Alcaide, Abraham; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Ministerio de Ciencia e Innovación (MICIN). España; European Union; Corporación Tecnológica de Andalucía; Agencia Nacional de Investigación y Desarrollo
In this article, an efficient and flexible communication schema for on-chip and off-chip communication is presented. With a reduced header size, the proposal can achieve high communication efficiency among the devices of a distributed static network or the internal components in a system-on-chip. In addition, the proposal is very versatile in terms of network configurations and topologies. An FPGA implementation of the proposal has been developed and thoroughly verified, both in simulation and when implemented in two different FPGA devices. The prototypes are exhibiting good results which validate the expected performance, with an efficient use of device resources. As a result, the proposed schema can both improve existing applications whose performance is affected by communication overhead and enable new industrial applications that require efficient communications in distributed static networks.
Open loop sigma-delta modulators for digital-to-analog converters with high speed improving using time interleaving
(Elsevier, 2020-10) Colodro Ruiz, Francisco; Martínez Heredia, Juana María; Mora Jiménez, José Luis; Torralba Silgado, Antonio Jesús; Universidad de Sevilla. Departamento de Ingeniería Electrónica; Ministerio de Ciencia, Innovación y Universidades (MICINN). España
Sigma-delta (SD) modulator based DACs are simple circuits with low accuracy requirements in their analog components. However, their signal bandwidth is limited by speed constrains. In this respect, Time-Interleaving (TI) allows the designer to trade-off between complexity and speed by replacing the original architecture by N parallel paths clocked at a frequency N times smaller. Unfortunately, this is only possible for small values of N because the resulting TI architecture has long combinatorial paths. These paths reduce the maximum clock rate. In closed-loop SD architectures these paths cannot be broken by the insertion of registers, because an increase of the loop delay compromises the stability of the modulator. This paper proposes a TI decomposition in open-loop SD modulators, which allows the insertion of as many registers as desired to shorten the critical combinatorial path. Consequently, the clock frequency (and, hence, the performances) can be increased at its maximum. The proposed method is illustrated with a second-order modulator, which has been synthesized in an FPGA (Spartan-6 xc6slx75t). Post-route static timing analysis and simulations show a considerable increase of performances. In authorś knowledge, it is the first time that TI is applied in open-loop SD modulators, resulting in very speed DACs.

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