1,429 research outputs found

    A Memory-Targeted Dynamic Reconfigurable Charge Pump to Achieve a Power Consumption Reduction in IoT Nodes

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    Targeting the more recently adopted low-power memories for data-logging operation in IoT nodes, this paper presents a simple reconfigurable dual-branch cross-coupled charge pump (CP) topology in which clock amplitude scaling and modulation of the number of stages are exploited to improve power efficiency and/or change the output voltage without degrading speed performance. The proposed solution allows a reduction of the power conversion losses, maintaining speed, maximum output voltage and silicon area unaltered as compared to the conventional charge pump. Post-layout simulation results confirm the effectiveness of the proposed topology which can be adapted to any other kind of linear charge pump

    RF-MEMS Switch Module in a 0.25 µm SiGe:C BiCMOS Process

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    Drahtlose Kommunikationstechnologien im Frequenzbereich bis 6 GHz wurden in der Vergangenheit in Bezug auf Leistungsfaehigkeit und Frequenzbereich kontinuierlich verbessert. Aufgrund der Skalierung nach dem Mooreschen Gesetz koennen heutzutage mm-Wellen Schaltkreise in CMOS-Technologien hergestellt werden. Durch die Einfuehrung von SiGe zur Realisierung einer leistungsfaehigen BiCMOS-Technologie wurde ebenfalls eine Verbesserung der Frequenzeigenschaften und Ausgangsleistungen erreicht, wodurch aktive CMOS- oder BiCMOS-Bauelemente vergleichbare Leistungsparameter zu III-V Technologien bei geringeren Kosten bereitstellen koennen. Bedingt durch das niederohmige Silizium-Substrat der BiCMOS-Technologie weisen vor allem passive Komponenten hoehere Verluste auf und weder III-V- noch BiCMOS-Technologien bieten hochlineare Schaltkomponenten mit geringen Verlusten und geringen Leistungsaufnahmen im mm-Wellen Bereich. RF-MEMS Schalter sind bekannt fuer ihre ausgezeichneten HF-Eigenschaften. Die Leistungsaufnahme von elektrostatisch angetriebenen RF-MEMS Schaltern ist vernachlaessigbar und es koennen im Vergleich zu halbleiter-basierten Schaltern hoehere Leistungen verarbeitet werden. Nichtsdestotrotz wurden RF-MEMS Schalter hauptsaechlich als eigenstaendige Komponenten entwickelt. Zur Systemintegration wird meist ein System-in-Package (SiP) Ansatz angewandt, der fuer niedrige Frequenzen geeignet ist, aber bei mm-Wellenanwendungen durch parasitaere Verluste an seine Grenzen stoesst. In dieser Arbeit wird ein in eine BiCMOS-Technologie integrierter RF-MEMS Schalter fuer mm-Wellen Anwendungen gezeigt. Das Design, die Integration und die experimentellen Ergebnisse sowie verschiedene Packaging-Konzepte werden beschrieben Zur Bereitstellung der hohen Auslenkungs-Spannungen wurde eine Ladungspumpe auf dem Chip integriert. Zum Schluss werden verschiedene, rekonfigurierbare mm-Wellen Schaltkreise zur Demonstration der Leistungsfaehigkeit des Schalters gezeigt.Wireless communication technologies have continuously advanced for both performance and frequency aspects, mainly for the frequencies up to 6 GHz. The results of Moore’s law now also give the opportunity to design mm-wave circuits using advanced CMOS technologies. The introduction of SiGe into CMOS, providing high performance BiCMOS, has also enhanced both the frequency and the power performance figures. The current situation is that the active devices of both CMOS and BiCMOS technologies can provide performance figures competitive with III-V technologies while having still the advantage of low cost. However, similar competition cannot be pronounced for the passive components considering the low-resistive substrates of BiCMOS technologies. Moreover, both III-V and BiCMOS technologies have the lack of low-loss and low-power consumption, as well as highly linear switching and tuning components at mm-wave frequencies. RF-MEMS switch technologies have been well-known with excellent RF- performance figures. The power consumption of electrostatic RF-MEMS switches is negligible and they can handle higher power levels compared to their semiconductor counterparts. However, RF-MEMS switches have been mostly demonstrated as standalone processes and have started to be used as commercial off-the-shelf (COTS) devices recently. The full system integration is typically done by a System-in-Package (SiP) approach. Although SiP is suitable for lower frequencies, the packaging parasitics limit the use of this approach for the mm-wave frequencies. In this thesis, a fully BiCMOS embedded RF-MEMS switch for mm-wave applications is proposed. The design, the implementation and the experimental results of the switch are provided. The developed RF-MEMS switch is packaged using different packaging approaches. To actuate the RF-MEMS switch, an on-chip high voltage generation circuit is designed and characterized. The robustness and the reliability performance of the switch are also presented. Finally, the developed RF-MEMS switch is successfully demonstrated in re-configurable mm-wave circuits

    A Silicon Carbide Power Management Solution for High Temperature Applications

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    The increasing demand for discrete power devices capable of operating in high temperature and high voltage applications has spurred on the research of semiconductor materials with the potential of breaking through the limitations of traditional silicon. Gallium nitride (GaN) and silicon carbide (SiC), both of which are wide bandgap materials, have garnered the attention of researchers and gradually gained market share. Although these wide bandgap power devices enable more ambitious commercial applications compared to their silicon-based counterparts, reaching their potential is contingent upon developing integrated circuits (ICs) capable of operating in similar environments. The foundation of any electrical system is the ability to efficiently condition and supply power. The work presented in this thesis explores integrated SiC power management solutions in the form of linear regulators and switched capacitor converters. While switched-mode converters provide high efficiency, the requirement of an inductor hinders the development of a compact, integrated solution that can endure harsh operating environments. Although the primary research motivation for wide bandgap ICs has been to provide control and protection circuitry for power devices, the circuitry designed in this work can be incorporated in stand-alone applications as well. Battery or generator powered data acquisition systems targeted towards monitoring industrial machinery is one potential usage scenario

    RF Power Transfer, Energy Harvesting, and Power Management Strategies

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    Energy harvesting is the way to capture green energy. This can be thought of as a recycling process where energy is converted from one form (here, non-electrical) to another (here, electrical). This is done on the large energy scale as well as low energy scale. The former can enable sustainable operation of facilities, while the latter can have a significant impact on the problems of energy constrained portable applications. Different energy sources can be complementary to one another and combining multiple-source is of great importance. In particular, RF energy harvesting is a natural choice for the portable applications. There are many advantages, such as cordless operation and light-weight. Moreover, the needed infra-structure can possibly be incorporated with wearable and portable devices. RF energy harvesting is an enabling key player for Internet of Things technology. The RF energy harvesting systems consist of external antennas, LC matching networks, RF rectifiers for ac to dc conversion, and sometimes power management. Moreover, combining different energy harvesting sources is essential for robustness and sustainability. Wireless power transfer has recently been applied for battery charging of portable devices. This charging process impacts the daily experience of every human who uses electronic applications. Instead of having many types of cumbersome cords and many different standards while the users are responsible to connect periodically to ac outlets, the new approach is to have the transmitters ready in the near region and can transfer power wirelessly to the devices whenever needed. Wireless power transfer consists of a dc to ac conversion transmitter, coupled inductors between transmitter and receiver, and an ac to dc conversion receiver. Alternative far field operation is still tested for health issues. So, the focus in this study is on near field. The goals of this study are to investigate the possibilities of RF energy harvesting from various sources in the far field, dc energy combining, wireless power transfer in the near field, the underlying power management strategies, and the integration on silicon. This integration is the ultimate goal for cheap solutions to enable the technology for broader use. All systems were designed, implemented and tested to demonstrate proof-of concept prototypes

    High-Voltage Integrated Circuits design and validation for automotive applications

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    Electronic Integrated Circuits (ICs) are an important pillar of the automotive market, especially since legal and safety requirements have been introduced to manage vehicles emissions and behaviors. Furthermore, the harsh environment and the tight safety requirements, summed with the market that is pushing to reduce the development lead time and to increase the system complexity, require to develop dedicated ICs for the automotive applications. This thesis presents some peculiar high-power and high-voltage ICs for automotive applications that have been studied, designed and developed taking into account all the requirements that automotive grade ICs have to respect, with emphasis on performance, quality and safety aspects. Particularly the thesis reports the design and validation of power management blocks and output drivers for inductive loads, showing how to fulfill in an effective way the performance, quality and safety targets according to the guidelines and the constraints of the latest automotive standards, like ISO26262 and AEC-Q100. All the designed ICs has been simulated and manufactured, including layout drawings, in a 0.35um HV-CMOS technology from AMS. The effectiveness and robustness of the proposed circuits has been validated on silicon and corresponded measurement results has been reported

    Hybrid monolithic integration of high-power DC-DC converters in a high-voltage technology

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    The supply of electrical energy to home, commercial, and industrial users has become ubiquitous, and it is hard to imagine a world without the facilities provided by electrical energy. Despite the ever increasing efficiency of nearly every electrical application, the worldwide demand for electrical power continues to increase, since the number of users and applications more than compensates for these technological improvements. In order to maintain the affordability and feasibility of the total production, it is essential for the distribution of the produced electrical energy to be as efficient as possible. In other words the loss in the power distribution is to be minimized. By transporting electrical energy at the maximum safe voltage, the current in the conductors, and the associated conduction loss can remain as low as possible. In order to optimize the total efficiency, the high transportation voltage needs to be converted to the appropriate lower voltage as close as possible to the end user. Obviously, this conversion also needs to be as efficient, affordable, and compact as possible. Because of the ever increasing integration of electronic systems, where more and more functionality is combined in monolithically integrated circuits, the cost, the power consumption, and the size of these electronic systems can be greatly reduced. This thorough integration is not limited to the electronic systems that are the end users of the electrical energy, but can also be applied to the power conversion itself. In most modern applications, the voltage conversion is implemented as a switching DC-DC converter, in which electrical energy is temporarily stored in reactive elements, i.e. inductors or capacitors. High switching speeds are used to allow for a compact and efficient implementation. For low power levels, typically below 1 Watt, it is possible to monolithically implement the voltage conversion on an integrated circuit. In some cases, this is even done on the same integrated circuit that is the end user of the electrical energy to minimize the system dimensions. For higher power levels, it is no longer feasible to achieve the desired efficiency with monolithically integrated components, and some external components prove indispensable. Usually, the reactive components are the main limiting factor, and are the first components to be moved away from the integrated circuit for increasing power levels. The semiconductor components, including the power transistors, remain part of the integrated circuit. Using this hybrid approach, it is possible in modern converterapplications to process around 60 Watt, albeit limited to voltages of a few Volt. For hybrid integrated converters with an output voltage of tens of Volt, the power is limited to approximately 10 Watt. For even higher power levels, the integrated power transistors also become a limiting factor, and are replaced with discrete power devices. In these discrete converters, greatly increased power levels become possible, although the system size rapidly increases. In this work, the limits of the hybrid approach are explored when using so-called smart-power technologies. Smart-power technologies are standard lowcost submicron CMOS technologies that are complemented with a number of integrated high-voltage devices. By using an appropriate combination of smart-power technologies and circuit topologies, it is possible to improve on the current state-of-the-art converters, by optimizing the size, the cost, and the efficiency. To determine the limits of smart-power DC-DC converters, we first discuss the major contributing factors for an efficient energy distribution, and take a look at the role of voltage conversion in the energy distribution. Considering the limitations of the technologies and the potential application areas, we define two test-cases in the telecommunications sector for which we want to optimize the hybrid monolithic integration in a smart-power technology. Subsequently, we explore the specifications of an ideal converter, and the relevant properties of the affordable smart-power technologies for the implementation of DC-DC converters. Taking into account the limitations of these technologies, we define a cost function that allows to systematically evaluate the different potential converter topologies, without having to perform a full design cycle for each topology. From this cost function, we notice that the de facto default topology selection in discrete converters, which is typically based on output power, is not optimal for converters with integrated power transistors. Based on the cost function and the boundary conditions of our test-cases, we determine the optimal topology for a smart-power implementation of these applications. Then, we take another step towards the real world and evaluate the influence of parasitic elements in a smart-power implementation of switching converters. It is noticed that the voltage overshoot caused by the transformer secondary side leakage inductance is a major roadblock for an efficient implementation. Since the usual approach to this voltage overshoot in discrete converters is not applicable in smart-power converters due to technological limitations, an alternative approach is shown and implemented. The energy from the voltage overshoot is absorbed and transferred to the output of the converter. This allows for a significant reduction in the voltage overshoot, while maintaining a high efficiency, leading to an efficient, compact, and low-cost implementation. The effectiveness of this approach was tested and demonstrated in both a version using a commercially available integrated circuit, and our own implementation in a smart-power integrated circuit. Finally, we also take a look at the optimization of switching converters over the load range by exploiting the capabilities of highly integrated converters. Although the maximum output power remains one of the defining characteristics of converters, it has been shown that most converters spend a majority of their lifetime delivering significantly lower output power. Therefore, it is also desirable to optimize the efficiency of the converter at reduced output current and output power. By splitting the power transistors in multiple independent segments, which are turned on or off in function of the current, the efficiency at low currents can be significantly improved, without introducing undesirable frequency components in the output voltage, and without harming the efficiency at higher currents. These properties allow a near universal application of the optimization technique in hybrid monolithic DC-DC converter applications, without significant impact on the complexity and the cost of the system. This approach for the optimization of switching converters over the load range was demonstrated using a boost converter with discrete power transistors. The demonstration of our smart-power implementation was limited to simulations due to an issue with a digital control block. On a finishing note, we formulate the general conclusions and provide an outlook on potential future work based on this research

    Study, optimization and silicon implementation of a smart high-voltage conditioning circuit for electrostatic vibration energy harvesting system

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    La récupération de l'énergie des vibrations est un concept relativement nouveau qui peut être utilisé dans l'alimentation des dispositifs embarqués de puissance à micro-échelle avec l'énergie des vibrations omniprésentes dans l environnement. Cette thèse contribue à une étude générale des récupérateurs de l'énergie des vibrations (REV) employant des transducteurs électrostatiques. Un REV électrostatique typique se compose d'un transducteur capacitif, de l'électronique de conditionnement et d un élément de stockage. Ce travail se concentre sur l'examen du circuit de conditionnement auto-synchrone proposé en 2006 par le MIT, qui combine la pompe de charge à base de diodes et le convertisseur DC-DC inductif de type de flyback qui est entraîné par le commutateur. Cette architecture est très prometteuse car elle élimine la commande de grille précise des transistors utilisés dans les architectures synchrones, tandis qu'un commutateur unique se met en marche rarement. Cette thèse propose une analyse théorique du circuit de conditionnement. Nous avons développé un algorithme qui par commutation appropriée de flyback implémente la stratégie de conversion d'énergie optimale en tenant compte des pertes liées à la commutation. En ajoutant une fonction de calibration, le système devient adaptatif pour les fluctuations de l'environnement. Cette étude a été validée par la modélisation comportementale.Une autre contribution consiste en la réalisation de l'algorithme proposé au niveau du circuit CMOS. Les difficultés majeures de conception étaient liées à l'exigence de haute tension et à la priorité de la conception faible puissance. Nous avons conçu un contrôleur du commutateur haute tension de faible puissance en utilisant la technologie AMS035HV. Sa consommation varie entre quelques centaines de nanowatts et quelques microwatts, en fonction de nombreux facteurs - paramètres de vibrations externes, niveaux de tension de la pompe de charge, la fréquence de la commutation de commutateur, la fréquence de la fonction de calibration, etc.Nous avons également réalisé en silicium, fabriqué et testé un commutateur à haute tension avec une nouvelle architecture de l'élévateur de tension de faible puissance. En montant sur des composants discrets de la pompe de charge et du circuit de retour et en utilisant l'interrupteur conçu, nous avons caractérisé le fonctionnement large bande haute-tension du prototype de transducteur MEMS fabriqué à côté de cette thèse à l'ESIEE Paris. Lorsque le capteur est excité par des vibrations stochastiques ayant un niveau d'accélération de 0,8 g rms distribué dans la bande 110-170 Hz, jusqu'à 0,75 W de la puissance nette a été récupérée.Vibration energy harvesting is a relatively new concept that can be used in powering micro-scale power embedded devices with the energy of vibrations omnipresent in the surrounding. This thesis contributes to a general study of vibration energy harvesters (VEHs) employing electrostatic transducers. A typical electrostatic VEH consists of a capacitive transducer, conditioning electronics and a storage element. This work is focused on investigations of the reported by MIT in 2006 auto-synchronous conditioning circuit, which combines the diode-based charge pump and the inductive flyback energy return driven by the switch. This architecture is very promising since it eliminates precise gate control of transistors employed in synchronous architectures, while a unique switch turns on rarely. This thesis addresses the theoretical analysis of the conditioning circuit. We developed an algorithm that by proper switching of the flyback allows the optimal energy conversion strategy taking into account the losses associated with the switching. By adding the calibration function, the system became adaptive to the fluctuations in the environment. This study was validated by the behavioral modeling. Another contribution consists in realization of the proposed algorithm on the circuit level. The major design difficulties were related to the high-voltage requirement and the low-power design priority. We designed a high-voltage analog controller of the switch using AMS035HV technology. Its power consumption varies between several hundred nanowatts and a few microwatts, depending on numerous factors - parameters of external vibrations, voltage levels of the charge pump, frequency of the flyback switching, frequency of calibration function, etc. We also implemented on silicon, fabricated and tested a high-voltage switch with a novel low power level-shifting driver. By mounting on discrete components the charge pump and flyback circuit and employing the proposed switch, we characterized the wideband high-voltage operation of the MEMS transducer prototype fabricated alongside this thesis in ESIEE Paris. When excited with stochastic vibrations having an acceleration level of 0.8 g rms distributed in the band 110-170 Hz, up to 0.75 μ\muW of net electrical power has been harvested.PARIS-JUSSIEU-Bib.électronique (751059901) / SudocSudocFranceF

    Design and Implementation of an Integrated Biosensor Platform for Lab-on-a-Chip Diabetic Care Systems

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    Recent advances in semiconductor processing and microfabrication techniques allow the implementation of complex microstructures in a single platform or lab on chip. These devices require fewer samples, allow lightweight implementation, and offer high sensitivities. However, the use of these microstructures place stringent performance constraints on sensor readout architecture. In glucose sensing for diabetic patients, portable handheld devices are common, and have demonstrated significant performance improvement over the last decade. Fluctuations in glucose levels with patient physiological conditions are highly unpredictable and glucose monitors often require complex control algorithms along with dynamic physiological data. Recent research has focused on long term implantation of the sensor system. Glucose sensors combined with sensor readout, insulin bolus control algorithm, and insulin infusion devices can function as an artificial pancreas. However, challenges remain in integrated glucose sensing which include degradation of electrode sensitivity at the microscale, integration of the electrodes with low power low noise readout electronics, and correlation of fluctuations in glucose levels with other physiological data. This work develops 1) a low power and compact glucose monitoring system and 2) a low power single chip solution for real time physiological feedback in an artificial pancreas system. First, glucose sensor sensitivity and robustness is improved using robust vertically aligned carbon nanofiber (VACNF) microelectrodes. Electrode architectures have been optimized, modeled and verified with physiologically relevant glucose levels. Second, novel potentiostat topologies based on a difference-differential common gate input pair transimpedance amplifier and low-power voltage controlled oscillators have been proposed, mathematically modeled and implemented in a 0.18ÎĽm [micrometer] complementary metal oxide semiconductor (CMOS) process. Potentiostat circuits are widely used as the readout electronics in enzymatic electrochemical sensors. The integrated potentiostat with VACNF microelectrodes achieves competitive performance at low power and requires reduced chip space. Third, a low power instrumentation solution consisting of a programmable charge amplifier, an analog feature extractor and a control algorithm has been proposed and implemented to enable continuous physiological data extraction of bowel sounds using a single chip. Abdominal sounds can aid correlation of meal events to glucose levels. The developed integrated sensing systems represent a significant advancement in artificial pancreas systems
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