Showing papers on "Boost converter published in 1978"

Simple switching control method changes power converter into a current source

Abstract: A switching converter with an LC output filter behaves as a loose-tolerance voltage-controlled current source if each switch closure is ended when switch current reaches an adjustable threshold. This converter is then combined with an external feedback to produce a precise output voltage. By generating a fixed voltage with a current source in this manner, the converter has many advantages including continuous protection of the switches, stable and equal load sharing when several converters are operated in parallel, inherent overload protection, automatic switch symmetry correction, and fast system response.

Push-pull switching power amplifier

Abstract: A true push-pull switching power amplifier is disclosed utilizing two dc-to-dc converters. Each converter is comprised of two inductances, one inductance in series with a DC source and the other inductor in series with the output load, and an electrical energy transferring device with storage capability, namely storage capacitance, with suitable switching means between the inductances to obtain DC level conversion, where the switching means allows bidirectional current (and power) flow, and the switching means of one dc-to-dc converter is driven by the complement of a square-wave switching signal for the other dc-to-dc converter for true push-pull operation. For reduction of current ripple, the inductances in each of the two converters may be coupled, and with proper design of the coupling, the ripple can be reduced to zero at either the input or the output, but preferably the output.

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.

New energy-storage dc-dc converter with multiple outputs

Abstract: New energy-storage dc-dc power converter is presented which provides multiple regulated and isolated dc output voltages. The conventional converter circuits have some defects. In the step-up-down type circuit, the operation is easy to be unstable when the feedback loop gain and/or the total output power grows larger. Meanwhile, although the operation of the step-down type circuit is stable, the extraordinary phenomena arise when the magnetomotive force of the energy-storage reactor is discontinuous for the light-load. These phenomena may be eliminated by the use of a dummy load or the reactor of sufficiently large inductance, but it makes the efficiency lower or the size and weight of the reactor larger. In the converter circuit presented here, the operation is stable and the extraordinary phenomena are eliminated by using the magnetic coupling among the multiple windings of the reactor. Hence, the dummy load can be removed and the inductance of the reactor can be made smaller.

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.

Single chip integrated analog-to-digital converter circuit powered by a single voltage potential

Abstract: A novel analog-to-digital converter is integrated on a semiconductor substrate utilizing I2 L techniques. The resulting converter, which utilizes dual slope integration to generate a digital signal, operates from a single low-voltage power supply and has few external components. The converter is suitable for integration with I2 L digital circuitry to provide a complete digital system, which operates in accordance with an analog input signal, on a single semiconductor chip.

Battery charger for electrical vehicle

Abstract: An on-board charger for an electric vehicle propulsion system which provides high charging capacity with minimum weight addition by sharing major elements of the electric vehicle power converter. In the preferred construction, the vehicle power converter has a magnetic element, an interphase transformer, connecting the output of the converter to the motor load. A primary winding is added to the interphase transformer for connection to a commercial AC power source. A phase controlled bridge also connected to the interphase transformer rectifies the AC power for charging the battery.

Elimination of current spikes in buck power converters

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.

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.

Power converter and regulation apparatus

Abstract: A power converter utilizes an inverter operating at a frequency near 30 kHz to produce an RF voltage which is divided by a reactive voltage divider, one portion of the divider including a saturable reactor having a control winding which is driven by a negative feedback current from a level sensing circuit connected to the converter output. DC voltage is provided by a bridge rectifier and filter connected across the saturable reactor. The circuit is especially useful for supplying electrical power efficiently to instrumentation on multikilovolt transmission lines where a transformer cascade is used to conductively isolate apparatus operating at the potential of the transmission line from a ground level power source.

DC to DC Converter

Abstract: DC to DC converter having DC input and DC output, a first switching element to repetitively connect and disconnect the DC input to an inductance winding connected through the first switching element. A source of pulse width modulated signal provides a control signal based on the detected output voltage of the converter. A second detector which detects a variation in the output load. A second switching element which controls the inductance of the winding is actuated based on the second detected signal.

Digital to analog converter having separate bit converters

Abstract: This invention relates to a digital to analog converter in general and specifically to unitary or monolithic miniature digital to analog converters designed to be fully embodied on a single one-half inch module without requiring external converter components. The digital to analog converter comprises n binary current sources and n two-way switches, n being the number of input word bits. Each switch is driven by a bit input and its function is to steer the current of the corresponding source either into a summing line for output or into a dump line. A primary feature of this converter is the separation of all individual bit converter structures comprising a current source and steering means into two different groups. In this scheme, a first group of converter structures is used to convert the high order bits and a second group of converter structures is used to convert the low order bits. This arrangement allows the provision of different types of current sources for the different converter structures depending upon the accuracy required for each current source. Control inputs are provided for acting upon the steering means to generate reference levels to which an input analog signal in an A/D converter is compared. By this technique, the D/A converters of the present invention may be utilized in A/D encoding and an improved conversion accuracy of about zero is provided.

High frequency switching regulator techniques

Abstract: The design and performance of non-resonant switching regulators operating at frequencies above 300kHz are discussed. The circuit arrangements and performance characteristics for a 150W, 600kHz inverter, a 25W, 300kHz multi-output quasisquarewave converter, a 2W, 600kHz buck-boost converter, and a 200W, 300kHz boost converter are presented.

A 10-bit monolithic tracking A/D converter

Abstract: A monolithic tracking analog-to-digital converter operating at 1.5MHz clock rate will be described, The device uses bipolar process for both linear and digital functions. Ten-bit accuracy is achieved without the need for post diffusion trimming.

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.

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.

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.

Ignition system for extending the lifetime of gas filled electric lamps

Abstract: The specification discloses an igniter circuit for extending the lifetime of a gas filled electric lamp. The igniter circuit includes a D.C. boost converter for generating an open circuit D.C. voltage for application to the lamp prior to ignition of the lamp. A resistance is initially connected between the converter and the lamp in order to limit the current applied to the lamp to a first predetermined level. A timer is connected to be energized concurrently with the D.C. boost converter in order to generate a timing signal after a predetermined time interval. A relay is responsive to the timing signal in order to establish a short circuit across the resistance in order to increase the current applied to the lamp to a second predetermined level higher than the first level. Current is not increased to the second predetermined level if the lamp ignites prior to generation of the timing signal. In this manner, the gas filled electric lamp utilizes only the current level required to sustain ignition, and therefore, the lifetime and reliability of the lamp and of the D.C. boost converter is extended.

Bias boost circuit for television receiver

Abstract: A bias boost circuit for a television receiver is disclosed, comprising a timing circuit for providing an exponentially decreasing bias to a video amplifier of the television receiver for a period of time corresponding to the initial warmup of the TV receiver, i.e. until the various amplifier and display portions are ready to display a high brightness image. The timing circuit comprises an RC circuit coupled to a power source of the TV receiver, whereby upon turn-on of the TV receiver the source's voltage is applied to the timing circuit, i.e. to its capacitor, to provide a decreasing voltage bias to the base of a transistor, whereby the transistor is gradually turned off thus decreasing exponentially a bias boost signal that is applied to the video amplifier and in particular, to its first stage.

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.

Ac/dc power converter for batteries and fuel cells. Annual report

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.

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.