621 Angewandte Physik
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Die vorliegende Erfindung betrifft ein Transmission Line Pulssystem zum Erzeugen eines elektrischen Pulses, sowie ein diesbezügliches Verfahren. Dabei umfasst das Transmission Line Pulssystem: eine Transmission Line, eine Energieversorgungsquelle zum Aufladen der Transmission Line und einen Entladungsschalter zum Auslösen einer Entladung der aufgeladenen Transmission Line, dadurch gekennzeichnet, dass die Transmission Line eine Vielzahl von Einzelsegmenten umfasst, wobei jedes Einzelsegment über ein zugehöriges Einstellglied mit einem gemeinsamen Massepotential elektrisch verbunden ist, und wobei zumindest eines der Einstellglieder einen Einstellkondensator und einen Einstellschalter aufweist.
Die vorliegende Erfindung betrifft eine Schaltungsanordnung mit einer Bootstrap-Schaltung, die zumindest eine Hauptkapazität aufweist, von der die erste Seite mit einem ersten Zweig der Schaltungsanordnung und die zweite Seite mit einem auf veränderlichem Potential liegenden zweiten Zweig der Schaltungsanordnung verbunden ist. Die vorgeschlagene Schaltungsanordnung zeichnet sich dadurch aus, dass die Bootstrap-Schaltung parallel zur Hauptkapazität wenigstens eine weitere Kapazität aufweist, die über eine zweite Versorgungsspannung auf eine höhere Spannung aufladbar ist als die Hauptkapazität und über wenigstens ein Schaltelement zur Unterstützung der Hauptkapazität zuschaltbar ist. Bei der vorgeschlagenen Schaltungsanordnung kann in Abhängigkeit von der Dimensionierung der Bootstrap-Kapazitäten eine sehr viel kleinere Fläche mit höherem oder gleich bleibenden Spannungseinbruch oder eine nicht so starke Flächenreduzierung mit kleinerem Spannungseinbruch verglichen mit einer herkömmlichen Bootstrap-Schaltung erzielt werden.
The paper illustrates the status quo of a research project for the development of a control system enabling CHP units for a demand-oriented electricity production by an intelligent management of the heat storage tank. Thereby the focus of the project is twofold. One is the compensation of the fluctuating power production by the renewable energies solar and wind. Secondly, a reduction of the load on the power grid is intended by better matching local electricity demand and production.
In detail, the general control strategy is outlined, the method utilized for forecasting heat and electricity demand is illustrated as well as a correlation method for the temperature distribution in the heat storage tank based on a Sigmoid function is proposed. Moreover, the simulation model for verification and optimization of the control system and the two field test sites for implementing and testing the system are introduced.
The current paper discusses the optimal choice of a filter time constant for filtering the steady state flux reference in an energy efficient control strategy for changing load torques. It is shown that by appropriately choosing the filter time constant as a fraction of the rotor time constant the instantaneous power losses after a load torque step can be significantly reduced compared to the standard case. The analysis for the appropriate choice of the filter time constant is based on a numerical study for three different induction motors with different rated powers.
In diesem Beitrag wird ein kapazitiver Low Power DC-DC Wandler mit 15 konfigurierbaren Übersetzungsverhältnissen, einem hohen Eingangsspannungsbereich von 5 V bis 20 V und einer konstanten Ausgangsspannung von 5 V vorgestellt. Bei einer Ausgangsleistung von 5 mW wird ein maximaler Wirkungsgrad von 81% erreicht. Die Implementierung erfolgt in einem 350 nm Hochvolt-CMOS-Prozess. Während es für niedrige Eingangsspannungen eine Vielzahl an Topologien und Konzepten gibt, wurden vollintegrierte SC-Wandler für höhere Eingangsspannungen (> 8 V) bisher nur wenig untersucht. Höhere Spannungen erfordern den Einsatz von Hochvolttransistoren und eine aufwändigere Ansteuerung. Um über einen weiteren Eingangsspannungsbereicht mit hoher Genauigkeit und hohem Wirkungsgrad zu wandeln, erweist sich die Topologie des rekursiven Switched-Capacitor Wandlers (RSC Wandler) als vorteilhaft. In der vorliegenden 4-Bit Implementierung ist der RSC Wandler aus N = 4 2:1 Serien-Parallel Wandler-Zellen aufgebaut. Durch verschiedene Anordnung der einzelnen Zellen können 2ᴺ -1 = 15 Wandlungsverhältnisse realisiert werden. Mittels Rekursion werden in jedem Wandlungsverhältnis alle Kapazitäten genutzt, wodurch die Stromfähigkeit und der Wirkungsgrad des Wandlers deutlich verbessert werden. Einheitliche 2:1 Wandler-Zellen ermöglichen einen modularen Aufbau des Layouts.
Substrate coupling is a critical failure mechanism especially in fast-switching integrated power stages controlling high-side NMOS power FETs. The parasitic coupling across the substrate in integrated power stages at rise times of up to 500 ps and input voltages of up to 40V is investigated in this paper. The coupling has been studied for the power stage of an integrated buck converter. In particular, dedicated diverting and isolation structures against substrate coupling are analyzed by simulations and evaluated with measurements from test chips in 180nm high-voltage BiCMOS. The results are compared regarding effectiveness, area as well as implementation effort and cost. Back-side metalization shows superior characteristics with nearly 100% noise suppression. Readily available p-guard ring structures bring 75% disturbance reduction. The results are applicable to advanced and future power management solutions with fully integrated switched-mode power supplies at switching frequencies >10 MHz.
Size and cost of a switched mode power supply can be reduced by increasing the switching frequency. The maximum switching frequency and the maximum conversion ratio are limited by the duty cycle of a PWM signal. In DCDC converters, a sawtooth generator is the fundamental circuit block to generate the PWM signal. The presented PWM generator is based on two parallel, fully interleaved PWM generator stages, each containing an integrator based sawtooth generator and two 3-stage highspeed comparators. A digital multiplexing of the PWM signals of each stage eliminates the dependency of the minimum on-time on the large reset times of the sawtooth ramps. A separation of the references of the PWM comparators in both stage allows to configure the PWM generator for a DCDC converter operating in fixed frequency or in constant on-time mode, which requires an operation in a wide frequency range. The PWM generator was fabricated in an 180 nm HV BiCMOS technology, as part of a DCDC converter. Measurements confirm minimum possible ontime pulses as short as 2 ns and thus allows switching frequencies of DCDC converters of >50 MHz at small duty cycle of <10%. At moderate duty cycles switching frequencies up to 100 MHz are possible.
This paper presents an integrated synchronous buck converter for input voltages >12V with 10MHz switching frequency. The converter comprises a predictive dead time control with frequency compensated sampling of the switching node which does not require body diode forward conduction. A high dead time resolution of 125 ps is achieved by a differential delay chain with 8-bit resolution. This way, the efficiency of fast switching DCDC converters can be optimized by eliminating the body diode forward conduction losses, minimizing reverse recovery losses and by achieving zero voltage switching at turn off. The converter was implemented in a 180nm high-voltage BiCMOS technology. The power losses were measured to be reduced by 30%by the proposed dead time control, which results in a 6% efficiency increase at VOUT = 5V and 0.2A load. The peak efficiency is 81 %.
Galvanic isolated gate drivers require a control signal as well as energy transmission from the control side (lowside) to the driver side (high-side). An additional backward signal transmission is preferred for error signals, status information, etc. This is often realized by means of several transformers or opto-couplers. Decreasing the number of isolation elements results in lower cost and a higher degree of miniaturization. This work presents a gate driver with bidirectional signal transmission and energy transfer via one single transformer. The key concept proposed in this paper is to combine bootstrapping to deliver the main gate charge for the driven power switch with additional energy transfer via the signal transformer. This paper also presents a very efficient combination of energy transfer to two high-side supply rails with back channel amplitude modulation. This way an isolated gate driver can be implemented that allows 100% pulse-width modulation (PWM) duty cycle at low complexity and system cost. The proposed high-side driver IC with integrated power supply, modulation and demodulation circuits was manufactured in a 180nm high-voltage BiCMOS technology. Measurements confirm the concept of bidirectional signal transmission with a 1MBit/s amplitude modulation, 10/20MHz frequency modulation and a maximum power transmission of 14mW via the transformer.
There is a growing need for motor drives with improved EMC in various automotive and industrial applications. An often referenced approach to reduce EME is to change the shape of the switching signal to reduce the EMI caused by the voltage and current transitions. This requires very precise gate control of the power MOSFET to achive better switching behaviour and lower EME without a major increase in switching losses. In order to find an optimal trade-off, this work utilizes a monolithic current mode gate driver with a variable output current that can be changed within 10ns. With this driver, measurements with different gate current profiles were taken. The di/dt transition was confirmed to be as important as the dv/dt transition in the power MOSFET. As a result of the improved switching behavior the emissions were reduced by up to 20dB between 7MHz and 60MHz with a switching loss that is 52% lower than with a constantly low gate current.