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Showing papers on "Buck converter published in 1978"


Patent
04 Apr 1978
TL;DR: In this paper, a dynamic dead band circuit is incorporated into a pulse width modulation current balance and output voltage regulation control circuit to prevent current imbalance from causing saturation of the power transformer core for all operating conditions of the converter including input voltage falling below its rated low-line value, sudden load surges, or turning off the converter power supply.
Abstract: A current balance arrangement for the power switching devices of a push-pull converter circuit is disclosed. A dynamic dead band circuit is incorporated into a pulse width modulation current balance and output voltage regulation control circuit to prevent current imbalance from causing saturation of the power transformer core for all operating conditions of the converter including input voltage falling below its rated low-line value, sudden load surges, or turning off of the converter power supply. Whenever the dynamic dead band circuit determines that inverter current flow is being terminated by the dead band interval of the converter clock, a control signal is sent to the pulse width modulation circuitry of the converter to effect inverter current termination prior to initiation of the clock dead band interval in subsequent cycles of converter operation. The invention eliminates the need for providing inverter power switching devices having closely matched electrical characteristics.

51 citations


Proceedings ArticleDOI
13 Jun 1978
TL;DR: It is demonstrated, first, how the complex modular converter structures can be easily modelled in the discontinuous current mode by use of the state-space averaging method and equivalent circuit approach and by taking advantage of the known properties and circuit models of the individual converter modules (boost and buck converters).
Abstract: It is demonstrated, first, how the complex modular converter structures (such as cascade og the boost and buck converters) can be easily modelled in the discontinuous current mode by use of the state-space averaging method and equivalent circuit apptoach and by taking adavntage of the known properties and circuit models of the individual converter modules (boost and buck converters). Then, the recently introduced new optimum topology switching dc-to-dc converter is analyzed in the discontinuous inductor current mode. Unlike other converters with two inductors (such as casaded boost-buck), the new converter has a unique feature that both inductor currents become discontinuous at the same instant, and remain so with the same second (decay) interval. Moreover, for the first time, the discontinuity of the inductor current takes place at a nonzero inductor current level, with dc curreny, passing through both inductors in the remaining third part of the switching period. It is shown howthis peculiar behaviour can be successfully modelled and a simple analytic criterion for determination of the boundary between the continuous and discontinuous inductor current mode is obtained.

20 citations


Patent
31 Oct 1978
TL;DR: In this article, a buck power converter with a center-tapped (primary and secondary) transformer between two switching power transistors operated in a push-pull mode and two rectifying diodes in the secondary circuit is shown to eliminate current spikes due to transformer saturation.
Abstract: Current spikes in a buck power converter due to commutating diode turn-off time is eliminated by using a tapped inductor in the converter with the tap connected to the switching transistor, without the commutating diode in the usual place, and instead connected to conduct current from one end of the tapped inductor remote from the load during the interval in which the transistor is not conducting. In the case of a converter having a center-tapped (primary and secondary) transformer between two switching power transistors operated in a push-pull mode and two rectifying diodes in the secondary circuit, current spikes due to transformer saturation are also eliminated by using a tapped inductor in the converter with the tap connected to the rectifying diodes and a diode connected to conduct current from one end of the tapped inductor remote from the load during the interval in which the transistors are not conducting.

13 citations


Book ChapterDOI
01 Jan 1978
TL;DR: In this article, a generalized computer-aided modeling and analysis of DC-DC converters is presented, which is applicable to all types of power stages and duty-cycle control, including continuous and discontinuous inductor current operation.
Abstract: Using discrete time state variable representation, a generalized computer-aided modelling and analysis of DC-DC converters is presented. The methodology provides exact modelling and is applicable to all types of power stages and duty-cycle control, including continuous and discontinuous inductor current operation. Converter stability, transient behavior and audio susceptibility can be analytically evaluated and predicted. The generalized theory of the proposed approach to converter modelling and analysis is presented first, followed by a demonstrative example applying the theory to a constant frequency buck converter operating in continuous and discontinuous inductor current mode. Excellent agreement with laboratory test data has been observed.

6 citations


Proceedings ArticleDOI
13 Jun 1978
TL;DR: Liapunov's direct stability method as applied to discrete systems and the method of paired systems due to Kaiman are used to obtain sufficient conditions for global stability as discussed by the authors, and the global convergence of a buck regulator is also investigated.
Abstract: Liapunov's direct stability method as applied to discrete systems and the method of paired systems due to Kaiman are used to obtain sufficient conditions for global stability. The global convergence of a buck regulator is also investigated.

4 citations


Patent
14 Aug 1978
TL;DR: In this article, two or more static converter switching circuits are connected in series across an input voltage source and have their primaries wound on a single power transformer core, each converter circuit includes a current primary winding so as to limit the current through the power switches during the switching periods.
Abstract: Two or more static converter switching circuits are connected in series across an input voltage source and have their primaries wound on a single power transformer core. Each converter circuit includes a current primary winding so as to limit the current through the power switches during the switching periods. The circuit arrangement allows equal input voltage distribution across the power switches and controls the current rise through each power switch during the turn ON and turn OFF times.

4 citations


Book ChapterDOI
01 Jan 1978
TL;DR: In this article, the buck converter is used to prevent overload on an electronic switch in ON-state by detecting the voltage which is on its main current electrodes and turning this switch to its OFF-state for a certain period of time as soon as a certain limit has been reached.
Abstract: This article shows that transistor choppers can compete technically as well as economically with SCR-choppers. The principle of a buck converter is briefly explained, and measures for the protection of electronic switches (single, or parallel array of transistors) against overload are stated. An overload on an electronic switch in ON-state is prevented by detecting the voltage which is on its main current electrodes and by turning this switch to its OFF-state for a certain period of time as soon as a certain limit has been reached. So-called relieving circuits (di/dt- and du/dt- limitations) without loss due to construction principles, which relieve the electronic switch during turn-ON and turn-OFF from undue power dissipation and which prevent the occurrence of excessive reverse voltage immediately following turn-OFF will be discussed and explained using oscillograms. These measures result in a simple, fail-safe and cheap chopper which, compared to a SCR-chopper, can be operated at a higher pulse repetition rate, whose switching states “continuously ON” and “continuously OFF” can easily be managed, and which, finally, - due to the lack of a forced commutation circuit - can be turned OFF at any time and under any load condition.

1 citations



ReportDOI
01 Aug 1978
TL;DR: In this article, the leading commutating circuit options for an advanced self-commutated-type power converter were tested and analyzed by computer simulation, and an analytical and experimental evaluation of advanced commutation circuits, an evaluation of alternative advanced bridge designs, selection of the most desirable conceptual design, and the development of a mathematical model of converter response are described.
Abstract: The leading commutating circuit options for an advanced self-commutated-type power converter were tested and analyzed by computer simulation. An analytical and experimental evaluation of advanced commutation circuits, an evaluation of alternative advanced bridge designs, selection of the most desirable conceptual design, and the development of a mathematical model of converter response are described. Experimental data and preliminary converter specifications are contained in the appendixes.

1 citations


Proceedings ArticleDOI
M. Kohno1, K. Kuwabara1
01 Oct 1978
TL;DR: In this article, a DC-to-DC converter which simultaneously regulates two output voltages individually by turning a transistor switch on and off to give good regulation and high conversion efficiency is introduced.
Abstract: This paper introduces a DC-to-DC converter which simultaneously regulates two output voltages individually by turning a transistor switch on and off to give good regulation and high conversion efficiency. The converter combines a buck and a buck-boost converter through one transistor switch; the buck circuit operates in the continuous inductor current mode, and the buck-boost circuit operates in the discontinuous inductor current mode. Together they can regulate two output voltages by controlling the duty ratio and operating frequency of the switching operation.

1 citations


Journal ArticleDOI
TL;DR: In this paper, a method for regulating a low-output-current, high-voltage (16 kV) flyback DC-DC converter without access to the high voltage side is described.
Abstract: A method is described for regulating a low-output-current, high-voltage (16 kV) flyback DC-DC converter without access to the high-voltage side. The voltage error, sensed at the collector of the output transistor where the flyback voltage is directly proportional to the voltage across the output capacitor, controls the duty cycle.

Patent
28 Sep 1978
TL;DR: In this paper, a DC-DC converter has a control, two switches, a transformer and two rectifier diodes, each switch is connected between an outer end of a winding and ground, and the converter provides stable operation with good voltage regulation over a wide range of load conditions without the use of feedback.
Abstract: Ein Gleichspannungswandler weist eine Steuerung, zwei Schalter, einen Transformator und zwei Gleichrichterdioden auf. A DC-DC converter has a control, two switches, a transformer and two rectifier diodes. Der Transformator weist eine erste Wicklung, eine zweite Wicklung und einen mittigen Abgriff auf. The transformer has a first winding, a second winding and a center tap. Zwischen dem mittigen Abgriff und Masse ist eine Eingangsspannung angelegt. Between the center tap and ground an input voltage is applied. Eine Anode jeder Diode ist mit den auseren Enden der beiden Wicklungen verbunden, und die Kathoden der beiden Dioden sind miteinander verbunden, um bezuglich der Masse einen positiven Ausgang bereitzustellen. An anode of each diode is connected to the outer ends of the two windings and the cathodes of the two diodes are connected together to provide a positive output with respect to ground. Jeder Schalter ist zwischen ein auseres Ende einer Wicklung und Masse geschaltet. Each switch is connected between an outer end of a winding and ground. Die Steuerung erzeugt Steuersignale, um die Schalter fur begrenzte Zeitraume in Gegenphasigkeit ein- und auszuschalten, um die auseren Enden der ersten und der zweiten Wicklung abwechselnd mit Masse zu verbinden, um zu bewirken, das ein Strom abwechselnd in einer der Wicklungen fliest und in der anderen Wicklung eine Spannung induziert, die zusatzlich zu der Eingangsspannung vorliegt, wodurch eine Ausgangsspannung bereitgestellt wird, die groser ist als die Eingangsspannung. The controller generates control signals to turn the switch for limited periods in phase opposition and off to alternately connect the outer ends of the first and second windings to ground, to cause a current to flow alternately in one of the windings and in the other winding induces a voltage, which is present in addition to the input voltage, whereby an output voltage is provided that is greater than the input voltage. Der Wandler liefert einen stabilen Betrieb bei einer guten Spannungsregelung uber eine breite Palette von Lastbedingungen ohne die Verwendung von Ruckkopplung. The converter provides stable operation with good voltage regulation over a wide range of load conditions without the use of feedback.