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An Efficient Supply Modulator for Linear Wideband RF Power AmplifiersTurkson, Richard 2011 August 1900 (has links)
Radio Frequency (RF) Power Amplifiers are responsible for a considerable amount of the power consumption in the entire transmitter-receiver (transceiver) of modern communication systems. The stringent linearity requirements of multi-standard transceivers to minimize cross-talking effects makes Linear Power Amplifiers, particularly class A, the preferred choice in broadband transceivers. This linearity requirement coupled with the fact that the Power Amplifier operates at low transmit power during most of its operation makes the efficiency of the entire transceiver poor. The limited transceiver efficiency leads to a reduction in the battery life of battery operated portable devices like mobile phones; hence drastically limiting talk time. To alleviate this issue, several research groups propose solutions to improve PA power efficiency. However, these solutions usually have a low efficiency at low power and are mostly limited to narrow bandwidth applications.
In this thesis, the efficiency of a class A Power amplifier in wideband wireless standards like WiMax is improved by dynamically controlling the bias current and supply voltage of the PA. An efficient supply modulator based on a switching regulator architecture is proposed for controlling the supply voltage. The switching regulator is found to be slew-limited by the bulky inductor and capacitor used to regulate the supply voltage. The proposed solution alleviates the slew rate limitation by adding a bang-bang controlled current source. The proposed supply modulator has an average power efficiency of 81.6 percent and is suitable for wireless standards with bandwidths up to 20MHz compared to the relatively lower efficiencies and bandwidths of state of the art modulators. A class-A PA is shown to promise an average power efficiency of 21.3 percent when the bias current is controlled dynamically and the supply voltage is varied using the proposed supply modulator. This is a significant improvement over the poor average efficiency of 1.06 percent for a fixed bias conventional linear class A PA.
The project has been simulated using the TSMC 0.18 micrometer technology.
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Modeling and Design of a Monolithic High Frequency Synchronous Buck with Fast Transient ResponseDeng, Haifei 18 February 2005 (has links)
With the electronic equipments becoming more and more complicated, the requirements for the power management are more and more strict. Efficient performance, high functionality, small profile, fast transient and low cost are the most wanted features for modern power management ICs, especially for mobile power. In order to reduce profile, the number of external components should be as small as possible, which means that compensator, ramp compensation, current sensor, driver and even power devices should be all implemented on a single chip, i.e. monolithic integration. Comparing with discrete switching DC-DC converter, monolithic integration brings a number of benefits and new design challenges. Besides monolithic integration, high switching frequency is another trend for power management ICs due to its higher bandwidth and the ability to further reduce external passive component size. Comparing with low frequency counterparts, high frequency switching converter design is more difficult in terms of the stability modeling, high switching loss and difficult current sensing etc. The objective of this dissertation is to study the design issues for monolithic integration of high frequency switching DC-DC converter. For this purpose, a high frequency, wide input range monolithic buck converter ASIC with fast transient response is designed based on advanced trench BCD technology.
Stability is the fundamental requirement in designing switching converter ASIC. Achieving this requires an accurate loop gain design, especially for monolithically integrated high frequency switching converter since compensator is fixed on silicon and loop delay is comparable with switching cycle. Since DC-DC switching converters are time-varying system, traditional small signal analysis in SPICE cannot be directly used to simulate the loop gain of this kind of system. A periodic small signal analysis based method is proposed to analyze and simulate DC-DC switching converter inside a SPICE like simulator without the need for averaging. This general method is suitable for any switching regulators. The results are accurate comparing with average modeling and experiment results even at high frequency part. A general procedure to design loop gain is proposed.
Several novel design concepts are proposed for monolithic integration of high frequency switching DC-DC converter; a novel control scheme-Cotangent Control (Ctg control) is proposed for fast transient response; In order to realize on-chip implementation of the compensator, especially for low frequency zero, active feedback compensator is developed and a general design procedure is proposed. Adaptive compensation concept is proposed to stabilize the whole system for a wide application range. Multi-stage driver and multi-section device concepts are investigated for high efficiency and low noise power stage design. And finally, a new noise insensitive lossless RC sensor is proposed for high speed current sensing.
At the end of this dissertation, the test results of the fabricated chip are presented to verify the correctness of these design concepts. / Ph. D.
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An Integrated, Lossless, and Accurate Current-Sensing Technique for High-Performance Switching RegulatorsForghani-zadeh, Hassan Pooya 02 June 2006 (has links)
Switching power converters are an indispensable part of every battery-operated consumer electronic product, nourishing regulated voltages to various subsystems. In these circuits, sensing the inductor current is not only necessary for protection and control but also is critical to be done in a lossless and accurate fashion for state-of-the-art advanced control techniques, which are devised to optimize transient response, increase the efficiency over a wide range of loads, eliminate off-chip compensation networks, and integrate the power inductor. However, unavailability of a universal, integrable, lossless, and accurate current-sensing technique impedes the realization of those advanced techniques and limit their applications. Unfortunately, use of a conventional series sense resistor is not recommended in high-performance, high-power switching regulators where more than 90% efficiency is required because of their high current levels. A handful of lossless current-sensing techniques are available but their accuracies are significantly lower than the traditional sense resistor scheme.
Among available lossless but not accurate techniques, an off-chip, filter-based method that uses a tuned filter across the inductor to estimate current flow and its accuracy is dependent on the inductance and its equivalent series resistance (ESR) was selected for improvement because of its inherent continuous and low-noise operation. A schemes is proposed to adapt the filter technique for integration by automatically adjusting bandwidth and gain of an on-chip programmable gm-C filter to the off-chip power inductor during the system start-up through measuring the inductance and its ESR with on-chip generated test currents.
The IC prototype in AMI s 0.5-um CMOS process achieved overall DC and AC gain errors of 8% and 9%, respectively, at 0.8 A DC load and 0.2 A ripple currents for inductors from 4 uH-14 uH and ESR from 48 mOhm to 384 mOhm when lossless, state-of-the-art schemes achieve 20 40% error and only when the nominal specifications of power component (power MOSFET or inductor) are known. Moreover, the proposed circuit improved the efficiency of a test bed current-mode controlled switching regulator by more than 2.6% at 0.8 A load compared to the traditional sense resistor technique with a 50 mOhm sense resistor.
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Zero Voltage Switching Hybrid Voltage Divider ConverterJeong, Timothy 01 June 2021 (has links) (PDF)
This project proposes a new hybrid voltage divider DC-DC converter that utilizes switching capacitors and inductors to produce zero voltage switching (ZVS) at the turn on state of its switches. By achieving ZVS, the switching losses are significantly reduced; thus, increasing the overall efficiency of the converter at various loads. The goal for this thesis is to perform analysis of the operation of the converter, derive equations for sizing the main components, and demonstrate its functionality through computer simulation and hardware prototype. Results of the simulation and hardware testing show that the proposed converter produces the desired output voltage while providing the zero voltage switching benefits. The converter’s efficiency reaches above 92% starting from 1A load and continues to increase to 97.6% at 4A load. Overall, results from this thesis verifies the potential of the proposed converter as an alternative solution to achieve a very efficient DC-DC solution when half of the input voltage is required at the output without the use of complex feedback control circuitry.
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Cascaded Linear Regulator with Positive Voltage Tracking Switching RegulatorNghe, Brandon K 01 May 2020 (has links) (PDF)
This thesis presents the design, simulation, and hardware implementation of a proposed method for improving efficiency of voltage regulator. Typically, voltage regulator used for noise-sensitive and low-power applications involves the use of a linear regulator due to its high power-supply rejection ratio properties. However, the efficiency of a linear regulator depends heavily on the difference between its input voltage and output voltage. A larger voltage difference across the linear regulator results in higher losses. Therefore, reducing the voltage difference is the key in increasing regulator’s efficiency. In this thesis, a pre switching regulator stage with positive voltage tracking cascaded to a linear regulator is proposed to provide an input voltage to a linear regulator that is slightly above the output of the linear regulator. The tracking capability is needed to provide the flexibility in having different positive output voltage levels while maintaining high overall regulator’s efficiency. Results from simulation and hardware implementation of the proposed system showed efficiency improvement of up to 23% in cases where an adjustable output voltage is necessary. Load regulation performance of the proposed method was also overall better compared to the case without the output voltage tracking method.
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Design and evaluation of a solid-state LiDAR system : for wireless distance measurementsHagstedt, Christian, Jönsson, Sebastian January 2022 (has links)
The advent of smarter vehicles coupled with declining costs for solid-state light detection and ranging (LiDAR) sensors unlocks the potential of cheaper devices that experience less mechanical wear while providing smaller form factors. The early state of the market makes evaluating the limited supply of available sensors interesting. This thesis investigated the possibility of creating a wireless distance measurement system, at relatively low cost, using a commercially available solid-state LiDAR sensor. A complete prototype was designed using a LeddarTech VU8 sensor. The system was fully integrated with a power supply PCB and a 3D printed enclosure. Distance data could be wirelessly transferred via Bluetooth using a Raspberry Pi 4 B. A graphical user interface (GUI) was developed to display distance data and to interact with the system in real-time. The system intends to provide a foundation for future work.
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Design and Implementation of Switching Voltage Integrated Circuits Based on Sliding Mode ControlRojas Gonzalez, Miguel Angel 2009 August 1900 (has links)
The need for high performance circuits in systems with low-voltage and low-power
requirements has exponentially increased during the few last years due to the sophistication
and miniaturization of electronic components. Most of these circuits are required to have a
very good efficiency behavior in order to extend the battery life of the device.
This dissertation addresses two important topics concerning very high efficiency
circuits with very high performance specifications. The first topic is the design and
implementation of class D audio power amplifiers, keeping their inherent high efficiency
characteristic while improving their linearity performance, reducing their quiescent power
consumption, and minimizing the silicon area. The second topic is the design and
implementation of switching voltage regulators and their controllers, to provide a low-cost,
compact, high efficient and reliable power conversion for integrated circuits.
The first part of this dissertation includes a short, although deep, analysis on class
D amplifiers, their history, principles of operation, architectures, performance metrics,
practical design considerations, and their present and future market distribution. Moreover,
the harmonic distortion of open-loop class D amplifiers based on pulse-width modulation
(PWM) is analyzed by applying the duty cycle variation technique for the most popular
carrier waveforms giving an easy and practical analytic method to evaluate the class
D amplifier distortion and determine its specifications for a given linearity requirement.
Additionally, three class D amplifiers, with an architecture based on sliding mode control, are proposed, designed, fabricated and tested. The amplifiers make use of a hysteretic
controller to avoid the need of complex overhead circuitry typically needed in other
architectures to compensate non-idealities of practical implementations. The design of the
amplifiers based on this technique is compact, small, reliable, and provides a performance
comparable to the state-of-the-art class D amplifiers, but consumes only one tenth of
quiescent power. This characteristic gives to the proposed amplifiers an advantage for
applications with minimal power consumption and very high performance requirements.
The second part of this dissertation presents the design, implementation, and testing
of switching voltage regulators. It starts with a description and brief analysis on the power
converters architectures. It outlines the advantages and drawbacks of the main topologies,
discusses practical design considerations, and compares their current and future market
distribution. Then, two different buck converters are proposed to overcome the most critical
issue in switching voltage regulators: to provide a stable voltage supply for electronic
devices, with good regulation voltage, high efficiency performance, and, most important,
a minimum number of components. The first buck converter, which has been designed,
fabricated and tested, is an integrated dual-output voltage regulator based on sliding mode
control that provides a power efficiency comparable to the conventional solutions, but
potentially saves silicon area and input filter components. The design is based on the idea of
stacking traditional buck converters to provide multiple output voltages with the minimum
number of switches. Finally, a fully integrated buck converter based on sliding mode
control is proposed. The architecture integrates the external passive components to deliver
a complete monolithic solution with minimal silicon area. The buck converter employs
a poly-phase structure to minimize the output current ripple and a hysteretic controller
to avoid the generation of an additional high frequency carrier waveform needed in
conventional solutions. The simulated results are comparable to the state-of-the-art works
even with no additional post-fabrication process to improve the converter performance.
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Highly-efficient Low-Noise Buck Converters for Low-Power MicrocontrollersAhmed, Muhammad Swilam Abdelhaleem January 2018 (has links)
No description available.
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Hocheffizienter DC/DC-Wandler auf Basis von GaN-Leistungsschaltern für Hochleistungs-Leuchtdioden im KraftfahrzeugWerkstetter, Mario 12 April 2018 (has links)
In der vorliegenden Arbeit werden Möglichkeiten zur Maximierung der Effizienz von stromregelnden DC/DC-Wandlern für den Betrieb von Hochleistungs-LEDs in PKW-und Motorrad-Beleuchtungseinrichtungen untersucht, mit dem Ziel, das Gewicht und den Energieverbrauch der Steuergeräte zu reduzieren und so zu dem stetigen Bestreben der Minimierung der Gesamtfahrzeugemissionen beizutragen.
Dafür werden verschiedene, teils sequenziell aufbauende Maßnahmen in Topologie, Bauelementen, Dimensionierung und Betriebsart betrachtet. Eine grundlegende Herausforderung für die Auslegung der Schaltung stellt dabei deren universelle Verwendbarkeit als Gleichteil in einem großen Bereich an Ausgangsstrom und -spannung in den individuellen Scheinwerfersystemen der verschiedenen Fahrzeugderivate dar.
Die Grundlage für die Verringerung der Verlustleistung bildet die Vereinfachung der Schaltreglertopologie hinsichtlich des Bauteilaufwands. Dies wird durch die Versorgung der Schaltung aus dem 48 V-Energiebordnetz und die Verwendung der Topologie des Tiefsetzstellers erreicht.
Elementarer Anteil dieser Arbeit ist die Untersuchung der Wirksamkeit des Einsatzes neuartiger Galliumnitrid-Leistungsschalter (GaN-HEMTs) anstelle der konventionellen Silizium-MOSFETs, was zunächst an Hand von Berechnungen und schaltungstechnischen, parasitärbehafteten und zeitvarianten Simulationen durchgeführt wird. Bereits bei herkömmlichen Schaltfrequenzen und hartgeschaltetem Betrieb können signifikante Verbesserungen des Wirkungsgrades erreicht werden.
Weitergehend wird der Nutzen der durch die GaN-Transistoren ermöglichten höheren Schaltfrequenzen eruiert. Die um bis zu Faktor 20 erhöhte Schaltfrequenz macht den Einsatz einer resonanten Betriebsart (Zero-Voltage-Switching) und einer Luftspule als Hauptinduktivität notwendig.
Auf Steuergeräteebene kann somit die Verlustleistung auf unter ein Drittel reduziert werden, was zudem ein deutlich einfacheres und kompakteres Gehäuse ermöglicht, wodurch das Gesamtgewicht etwa halbiert werden kann.
Abschließend wird die Schaltung in einem Prototypen praktisch umgesetzt und die Funktionsfähigkeit im ZVS-Betrieb bei Schaltfrequenzen von bis zu 10 MHz verifiziert. / This thesis deals with the research of possibilities for maximising efficiency of current-regulating DC/DC-Converters for driving high-power-LEDs in passenger-car- and motorcycle-lighting-devices. The ambition is to reduce weight and energy-consumption of the electronic-control-units, to contribute to reach the continuously decreasing target-values for vehicle-emissions.
Therefor different approaches in topology, components, design and operating mode are considered. A key-challenge for the circuit-design is the common-part-strategy for usage in many individual vehicle-headlamp-systems with a wide range of output-current and LED-string-voltages.
Basis for the reduction of power-losses is the simplification of the converters topology in terms of quantity of components. This is achieved by using the 48 V -vehicle-electrical-system as voltage-supply and a step-down-topology.
Mainpart of this research is about the potential benefits of applying novel Galliumnitride High-electron-mobility-transistors (GaN-HEMTs) instead of silicon MOS-FETs. Initially this is done by calculations and parasitic-afflicted, timevariant circuit-simulations.
Already in hardswitching operation under conventional switching-frequencies significant improvements in converter-efficiency can be achieved.
Furthermore the advantages of higher switching-frequencies, offered by the GaN-transistors, are investigated. Up to 20 times higher switching-frequencies necessitate a resonant operating mode of the circuit (Zero-voltage-switching) and the use of an aircoil as main-inductor.
On ECU-level power-losses can be reduced down to less than one third, which enables a more simplified and compact housing-concept, so that the overall weight can drop to about the half.
Finally the designed circuit is build up in a prototype and the functional capability is verified in ZVS-mode with up to 10 MHz switching-frequency.
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