Showing papers on "Buck–boost converter published in 1978"

Dynamic current balancing for power converters

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.

Isolation and multiple output extensions of a new optimum topology switching DC-to-DC converter

Abstract: The recently introduced new optimum topology dc-todc converter is extended in a simple and elegant manner to provide dc isolation and multiple outputs. In comparison with the sinle-transistor isolated forward and flyback converters operated under the same conditions, the single-transistor isolated new converter is shown to have equal or lower stress levels on the transistor, diode, and capacitor ripple current, and can utilize an isolation transformer with lower core and copper losses. Measurements of cross- and self-regulation properties of a two-output 45 W test converter are presented.

Device for energizing a D.C. motor, comprising an accumulator battery

Abstract: A small lightweight power-supply device a d.c. motor powered either by the a.c. supply voltage or by an accumulator battery which dissipates little power and has a well-defined output characteristic for a wide range of input voltages. The device comprises a flyback converter, the forward sweep time being a function of the output voltage and the current through the primary winding of the transformer of the flyback converter. The forward sweep time is controlled by a control circuit which is integrated for the greater part. There is provided a starting circuit. A level detector in the control circuit ensures that this circuit is activated only when its supply voltage, which is applied via the secondary winding of the transformer, is sufficiently high.

Discontinuous inductor current in the optimum topology switching converter

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.

DC-DC Converter for solid state watches

Abstract: A DC-DC converter for supplying a sufficient power voltage for solid state watches includes field-effect mode transistors operatively associated with charging and discharging paths of multi-stage capacitors which are primary components of the DC-DC voltage converter. The field-effect mode transistors are responsive to outputs from a level converter which in turn converts its input voltage to charge voltage at the last stage capacitor in response to enable signals. During the initial status of operation, the field effect mode switching transistors and the level converter are driven via the parasitic diodes of the field effect mode transistors, P-N junction type diodes provided for protecting the parasitic diodes from damage, or P-N junction type diodes provided exclusively for initiating purposes.

Control circuit for static converter - has smoothing unit with output added to current regulator output

Abstract: The control unit, for a static converter, has a circuit whose current regulator is connected before the converters control set and whose comparator compares the actual with the required load current. The output voltage (U) of the converter (2) passes over a smoothing unit (14) and is added (10) to the output (UR) of the current regulator (6) to form the input to the converter. The smoothing time constant of the feedback path between the converter's output and the adder (10) is half as large as that for current regulation.

A single-chip C 2 MOS A/D converter for microprocessor systems

Abstract: This paper will discuss a single-chip C2MOS 12/10 bit A/D converter, including an 8-channel analog multiplexer, powered by a single 5V supply.

Static converter suitable for high input voltage applications

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.

AC to DC Converter with enhanced buck/boost regulation

Abstract: This closed loop potential regulated ac-dc power supply comprises a power transformer having two secondary windings and a compensating transformer having two compensating windings connected individually in series circuit with the principal power supply secondary windings. The other secondary windings on the power transformer supply exciting windings for compensating variations in output potential by control of the compensating transformer control circuitry which has an input circuit connected across the load and an output for varying the ac supply to the exciting windings inversely of variations in load potential. A differential amplifying circuit is used for determining the load potential error and driving a transistor effectively to insert a dc component in inverse feedback relationship into the exciting windings of the compensating transformer. As the output potential error increases, the control current is decreased, and conversely. The change in control current flow is enhanced in that the transistor responds immediately to the change in the output potential and additionally by the operation of the differential amplifying circuit.

A precision voltage-to-frequency converter

Abstract: A monolithic voltage-to-frequency converter offering 0.015% nonlinearity will be covered. The design incorporates ion-implanted zener references and high-speed circuit technology to minimize error.

Single-Ended DC-to-DC Converter with Two Individually Controlled Outputs

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.

Static converter equipment

Abstract: A static converter equipment comprising at least two converters, each with a DC terminal; each converter having a load with a feeding point connected to the DC terminal of the converter, the converters being arranged to work in offset phase relation to each other. The feeding points are interconnected with impedance means with resistance of at least the same order of magnitude as the load resistance and an impedance at the most of the same order of magnitude as the load impedance.

Novel regulation method for low-current, high-voltage-output flyback DC-DC converter with isolation

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.

Gleichspannungswandler DC voltage converter

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.