Showing papers on "Forward converter published in 1981"

DC-to-DC Voltage converter

Abstract: A DC-to-DC voltage converter is disclosed for converting the voltage from a battery to provide a power supply voltage whose value can be equal to the battery voltage multiplied by or divided by a non-integral factor, e.g. 2/3. The converter operates on the principle of capacitor charge switching, and high conversion efficiency is achieved in operation at very low levels of supply current, such as are utilized in an electronic timepiece.

A Normalized Model for the Half-Bridge Series Resonant Converter

Abstract: Closed-form steady-state equations are derived for the halfbridge series resonant converter with a rectified (dc) load. Normalized curves for various currents and voltages are then plotted as a function of the circuit parameters. Experimental results based on a 10-kHz converter are presented for comparison with the calculations.

Bi-lateral four quadrant power converter

Abstract: A power converter which supplies AC or positive or negative DC output voltage with positive or negative current while isolating the output voltage from the input power source This converter includes a pulse width modulator converts power amplitude signals to pulses of proportionate width A power driver circuit applies these pulses to a sychronous demodulator and low pass filter via a pulse transformer A low output impedance is presented to all output disturbances such that the converter can source or sink current in true four quadrant operation, including the passing of power from output to input when a load voltage exceeds the intended supply voltage

Dual mode dc/dc converter.

Abstract: A DC/DC converter operates at peak efficiency in either of two output current level states in response to the power demands of an associated electronic device, thereby reducing wasted current to a minimum. The converter is designed to operate from a one-cell battery, and is particularly suited to an integrated circuit implementation.

Analysis and design of a push-pull current-fed converter

Abstract: Four modes of operation are possible for the basic push-pull current-fed converter. Each mode is analyzed, circuit waveforms are explained, and relationships that influence the converter design are developed. Various design options and selection guidelines are presented along with experimental results.

Current control apparatus for a flyback capacitor charger

Abstract: A DC to DC flyback converter for charging a capacitor in which the maximum current supplied from a battery to the converter's transformer is determined solely by the battery recovery voltage, circuit resistances, the transformer turns ratio and semiconductor junction voltages.

Single phase and three phase AC to DC converters

Abstract: A single phase AC to DC power converter is provided which accepts a single AC line input voltage and provides a DC output voltage. Input current feedback is used to control the converter and to provide high quality sinusoidal line currents in phase with the applied line voltage. In another embodiment, a three phase AC to DC converter is realized as a delta connection of three isolated single phase AC to DC converters. Reduction in peak transistor currents of the switching transistor in each single phase converter is accomplished by the introduction of third harmonics to each of the single phase AC to DC power converters. Each of the three single phase AC to DC converters are synchronized so that the current pulses at the outputs of the three AC to DC converters are staggered in time reducing the amount of filtering required at the load.

Pulse with modulated voltage converter for generating a preferably sinusoidal alternating voltage

Abstract: Un convertisseur de tension a largeur d'impulsion modulee convertit une tension a courant continu en une tension sinusoidale alternative a basse frequence pour etre utilise comme un generateur de signaux de sonnerie pour des echanges telephoniques. A voltage converter is modulated pulse width converts DC voltage has an alternating sinusoidal voltage at low frequency to be used as a ringing signal generator for of telephone exchanges. Le convertisseur comprend un etage de puissance comprenant un transformateur a noyau de ferrite (T) avec deux commutateurs (Pf, Pr) sur le cote primaire (cote batterie) et deux commutateurs (S1, S2) sur le cote secondaire (cote charge). The converter comprises a power stage comprising a transformer has ferrite core (T) with two switches (Pf, Pr) on the primary side (battery side) and two switches (S1, S2) on the secondary side (side load). Les commutateurs sont commandes par des impulsions de commande provenant d'un modulateur de largeur d'impulsion (PM) avec un debit variable d'impulsion de maniere telle qu'ils soient commutes avec une frequence bien superieure a la frequence du courant alternatif sinusoidal et de maniere telle qu'une impulsion du flux d'energie entre la batterie et la charge soit obtenue. The switches are control by control pulses from a pulse width modulator (PM) with a flow variable pulse manner such that they are well commutes with a superior frequency to the frequency of the sinusoidal alternating current of way such that a pulse of energy flow between the battery and the load is achieved.

AC/DC or DC/AC Converter system with improved AC-line harmonic reduction

Abstract: In a transformer-rectifier converter system, at least one inductance is inserted in the commutation path of two adjacent diode or thyristor devices in a cluster of three devices related to a common DC polarity pole, the reactance due to such inductance being sufficient to lengthen the commutation overlap thereby to minimize AC line harmonics. The invention is applicable to AC/DC as well as to DC/AC conversion.

Free-running blocking oscillator-type converter

Abstract: A free-running blocking oscillator-type converter for producing a controlled output signal. The converter is provided with a primary winding of a transformer, a switching transistor, and a resistor which are connected in series with one another between first and second input terminals of the converter. The transformer is further provided with a feedback winding which is coupled to the base terminal of the switching transistor. In some embodiments, optoelectronic coupling devices are used in a sensor arrangement for providing a control signal responsive to variations in the magnitude of the output signal of the converter. In other embodiments, such variations in the output signal of the converter are sensed by a transformer winding. Circuitry is disclosed for applying the sensor control signal selectably to the base and emitter terminals of the switching transistor.

A current sourced inverter with saturating output transformer

Abstract: A current sourced inverter with saturating output transformer offers advantages where a DC converter must regulate an isolated output voltage over a 10 to 1 range of input voltage in a dense package capable of 300 watt output.

Voltage balance control for split capacitors in half bridge DC to DC converter

Abstract: An AC to DC converter that utilizes a split capacitor, half bridge, DC to DC converter compensates for unequal voltages across each member of a split capacitor bank. A voltage balance control circuit senses any differences in voltages across the member capacitors and generates an error correcting signal for modifying steering signals to an inverter that is used to convert a DC signal from the half bridge DC to DC converter to a high frequency pulse width modulated AC signal by alternately placing each member of the split capacitor bank and consequently their stored energy across the output terminals of the inverter. The error signal causes the steering signals to connect the member capacitor with the larger sensed voltage across the output terminals for a relatively larger period of time than the capacitor with the lesser sensed voltage.

Statistically adaptive analog to digital converter

Abstract: An improvement in an analog-to-digital converter wherein a series string of capacitors is utilized to generate reference voltages for the comparators of the converter. The digitized output of the converter is then used to control a predetermined timed discharge from a selected one of the series string of capacitors. The converter, as described, may be used in a video system as an adaptive contrast enhancement mechanism.

Two-stage a-to-d converter

Abstract: A two-stage analog-to-digital converter wherein the first stage is a resistor-string d-to-a converter controlled by a successive-approximation register, functioning in a first phase of the conversion operation to determine a set of higher order bits of the digital output signal The second stage is a dual-slope integrating-type a-to-d converter functioning in a second phase of the conversion operation to determine the remaining lower-order bits of the digital output signal The dual-slope converter receives a reference signal derived from two adjacent junction points of the first-stage resistor-string d-to-a converter corresponding to the higher order bits determined in the first phase of operation, thereby to assure high resolution performance

Integrated circuit comprising a plurality of voltage-current converters

Abstract: An integrated circuit comprising a plurality of adjustable voltage-current converters, of which one converter is employed as a reference converter. The reference converter is included in a control loop. To the input of the reference converter an input voltage is applied in that a first current is passed through a reference resistor connected to said input. A second current, which is in a fixed ratio to said first current, is compared with the output current of the reference converter and this reference converter is then biassed so that its output current corresponds to said second current. In this way the transconductance of the reference converter is determined by the reference resistor and the ratio of the first and the second current, so that this transconductance is highly independent of process, temperature and supply-voltage variations. The other converters are biassed by signals derived from the bias signals for the reference converter and thus have corresponding transconductances.

Self-oscillating DC to DC converter

Abstract: A self-oscillating DC to DC converter which includes either two or four transistors, three transformers (a converting transformer, a driving transformer and a current transformer) and an inductance. The operating frequency of the converter is fixed by the saturation time of the driving transformer. The base currents of the transistors are mainly supplied by the current transformer so as to be in proportion to the collector currents of the transistors. The operating frequency of the converter is kept constant in spite of load fluctuations. The inductance which is connected in series between a winding of the converting transformer and a winding of the driving transformer. The inductance prevents the two or four transistors from being `on` simultaneously.

Consumable electrode type arc welding machine

Abstract: PURPOSE:To provide a titled welding machine which permits the reduction in size and capacity of a main transformer and is stable in welding performance, by converting AC of a commercial frequency to AC of a high frequency with a converter and an inverter, and supplying the same to the primary side of a high frequency transformer. CONSTITUTION:After the AC of a commercial frequency supplied to input terminals 100, 100' upon starting of welding is converted to DC with a converter 12, an inverter 14 is operated to convert the DC output of the converter 12 to high frequency AC. This high frequency AC is dropped in voltage with a high frequency transformer 18 and is supplied to a bridge circuit 20, which supplies the rectified current to terminals 101, 101' by firing the 1st, 2nd thyristors 20a, 20b or firing the 2nd, 3rd thyristors 20b, 20c. Since no large welding current can flow to the converter 14 and the inverter 12, the converter and the inverter of small capacity having intricate functions are usable, and the consumable electrode type arc welding machine which is small in size, light in weight and is in expensive is obtained.

DC/AC High Power Cell Structure Improves Sine Generator Performance

Abstract: A new generation of dc/ac sine generators, based on dc/dc, pulse-width modulation (PWM) storage converter structure operating with rectified sine wave control and associated with a controlled bridge, is described. The efficiency, harmonic distortion, and transien't behavior are better in dc/dc sine convertors than conventional dc/ac sine convertors. Continuous non-linear or linear methods previously described can be extended to design this structure.

A four quadrant ac and dc to ac and dc converter with two or more independently controlled loads

Abstract: Individual load circuits which are supplied by a series capacitor inverter-converter cannot be controlled independently. Disclosed is a class of power converter which extracts electric energy from a source of AC or DC power and conveys this energy through series resonant circuits (C12, L1, S1, W11 and C12, L1, S2, W12) to two or more loads in an independently controllable form.

Digital-to-analog converter and analog-to-digital converter with controllable bi-polar and uni-polar capability

Abstract: The digital-to-analog converter comprises an R-2R ladder network with bit controlled current steering switches connecting the legs of the ladder network to first and second current buses. First and second current-to-voltage converters are connected to the current buses respectively, the second current-to-voltage converter being connected through a switch to the input of the first current-to-voltage converter. A uni-polar/bi-polar control signal renders the switch conductive or non-conductive in accordance with the data format desired. The digital-to-analog converter is also utilized in a successive approximation analog-to-digital converter.

Analog-to-digital converter circuit

Abstract: PURPOSE:To reduce the error in conversion, by forming a reference voltage at A/D conversion of lower-order bits based on upper-order bits of a digital output and providing an offset corresponding to the upper-order bits for the reference voltage. CONSTITUTION:A 3-bit parallel A/D converter 11 converts an analog input voltage Vin into digital outputs, upper-order three bits H2-H0 and lower-order three bits L2-L0 in time division. The signals H2-H0 are applied to a latch 15 in three bits and switches 12, 13 are changed over into inverted state as shown in figure. The signals H2-H0 from the latch 15 are applied to a D/A converter 16, where the signals are converted into an analog voltage V16 having a value three times the signals H2-H0 and the analog voltage is applied to the converter 11 through the switch 13 as a reference voltage for lower limit. The voltage V16 is offset by 8V at a DC power supply 17 and applied through the switch circuit 12 as a reference voltage for upper limit for the converter 11. Thus, errors at a joint between the upper-order and the lower-order bits can be eliminated.

Flash device of a camera

Abstract: A flash device for photography includes a DC/DC converter for boosting a DC power source voltage and applying a voltage to a main capacitor for supplying an energy for driving a flashlight tube. The converter has control means operative in response to the trigger operation by a start operating switch to detect any reduction in the charging current of the main capacitor and stop said operation. The flash device is provided with another switch means for enabling the operation of the converter independently of the start operating switch. Said another switch means is operative to operate the converter until the charging voltage of the main capacitor reaches a sufficient value to drive the flashlight tube.

Cross-tied current regulator for load commutated inverter drives

Abstract: A control system for an AC motor drive including a source side converter and a load side converter coupled together by means of a DC link circuit wherein the current in the DC link circuit is controlled by either the source side converter or load side converter depending upon which converter is capable of control. This is achieved by crosstieing a signal from the normal regulating path in the source side converter control to the alternate regulating path in the load side converter control. This signal is chosen to be indicative of the source side converter controller being unable to control current, and may be derived from current error. This signal operates to alter the firing angle of the load side thyristor bridge to regulate the DC link current in the event the source side converter is unable to maintain the required current regulation.

Ringing signal supply

Abstract: A ringing signal supply, provided at a concentrator remote from a switching office, compares a fraction of its output with a low level reference ringing signal supplied from the switching office, and uses the comparison result to control a high voltage chopper which connects one of two d.c. supply voltages via a low pass filter to the output to produce the ringing signal at a desired frequency. A d.c.-d.c. forward converter produces the two d.c. supply voltages commonly for a plurality of ringing signal supplies whenever at least one of them is to produce a ringing signal.

Spannungsmesseinrichtung zur ventilsteuerung von stromrichtern in hgue-anlagen

Abstract: In the case of a device for producing the correct-phase image of the high AC voltage (U1) of a network for controlling the line-commutated valves of a converter, which is connected to the network via a converter transformer (1, 2, 3, 4), in a high-voltage DC transmission system, an auxiliary winding (6) is provided in the converter transformer.

DC/DC voltage converter having mains power supply isolation for input voltages having an extremely large variation range

Abstract: A DC/DC voltage converter having mains power supply isolation for input voltages (UE) having an extremely large variation range contains a switching transistor (T3) in whose collector circuit there is located a transformer (U) having primary, secondary and auxiliary windings (1,2; 6,7,8; 3,4), and in whose emitter circuit there is located an emitter resistor (RE) on which a voltage (UE) is picked off which is proportional to the current (i). It furthermore contains a control-pulse circuit (ST) having a first circuit (IC1), which is connected as a voltage-controlled multivibrator and supplies triggering signals via a first differentiating element (C4, D4) to a second circuit (IC2) which is connected as a triggerable comparator. The comparator (IC2) compares the voltage dropped on the emitter resistor (RE) with a fixed reference voltage (Uref). The voltage produced in the auxiliary winding (3, 4) is used to control the frequency of the voltage-controlled multivibrator (IC1) as a function of the load on the output of the transformer (U) and, in addition, to produce an auxiliary voltage (UH) as the voltage supply for the control-pulse circuit (ST). While the DC/DC voltage converter is being switched on, the auxiliary voltage (UH) is produced via a separate starting circuit (AS) which operates only until the flyback converter is oscillating.

Start-Up Transient of a DC-to-DC Converter Powered by a Current-Limited Source

Abstract: An analysis technique is presented which permits the designer to explore the start-up transient of a dc-to-dc converter when it is powered by a current-limited source. The current versus voltage characteristics of the source are superimposed upon those of the dc-to-dc converter. By noting the nature of the intersection of these curves in the voltage-current plane, we are able to predict whether or not the converter is able to start up while powering a specified load.

High-efficiency push-pull saturation converter

Abstract: To increase the efficiency of a push-pull saturation converter, a choke is introduced in a common emitter circuit of switching transistors in the converter. In addition, a constriction may be provided in a center leg of a transformer core of a switching transformer within the converter. To further improve efficiency, an RC acceleration element may be provided in a base circuit for the switching transistors.

Method and circuit arrangement for regulating the output voltage of an externally controlled DC voltage converter

Abstract: In order to regulate the output voltage of an externally controlled DC voltage converter, an output signal from a pulse-width modulation stage in the secondary circuit is transmitted, by means of a current transformer (Tr1), to the control device (St) of the actuating transistor (Ts3). In the event of an overvoltage on the secondary side, an astable stage (Ast) is activated whose output pulse sequence inhibits the actuating transistor (Ts3) via the control device (St).

Spindle drive generating system

Abstract: PURPOSE:To prevent the mutual interference of frequencies between the input and the output by providing a beat phenomenon detector when an AC generator is driven by a variable speed drive source and a load is connected through a stationary converter, thereby correcting a frequency command. CONSTITUTION:An AC generator 1 is driven by an engine or the like, and electric power is supplied through a stationary converter 2 which has a power reactor 3 and a power inverter 6 to a load 7. At this time, a beat phenomenon detector 10 is provided at the output side of the converter 2, a frequency command to a frequency converter 9 is corrected by the output, thereby slightly displacing the frequency command. Accordingly, frequency difference can be always produced between the input and the output of the converter 2, thereby reducing the size of the system without increasing the reactor 4 and the condenser 5 in the converter 2 and preventing the beat phenomenon which occurs when the frequencies of the input and output approach to each other.