Showing papers on "Forward converter published in 1974"

DC to DC Voltage converter

Abstract: A DC voltage source of amplitude below the DC voltage requirement of a load to be energized drives a pair of complementary transistors which are alternately turned on and off to apply supply voltage alternately to each of two capacitors connected in series. The sum voltage of the two capacitors is applied, in one embodiment, directly to a voltage regulator and filtered and, in another embodiment, is added to the DC source voltage prior to being regulated and filtered. The converter output is capacitively coupled to the DC supply voltage, thus furnishing a common AC connection.

DC component suppression in zero CF IF systems

Abstract: Disclosed is a zero center frequency IF system having an all digital complex multiplier in which DC components in the IF signals are removed from an A/D converter output. Any DC level which reaches the input of the A/D converter or any misalignment in the A/D converter causes the digital outputs to contain unequal numbers of positive and negative words. The sign bit of the digital output is coupled to the input of an integrator which generates a DC output proportional to the DC offset in the A/D converter output. The integrator output is substracted from the IF signal coupled to the input of the A/D converter and cancels any DC components present.

Auto-ranging system for an electronic energy meter

Abstract: An auto-ranging system for an electronic watt-hour meter includes a current transformer for measuring the electrical current in at least one line of an electrical power consuming system. The measured current is converted to a voltage which is proportional to the measured current by means of a current/voltage converter. A means responsive to the output of the current transformer incrementally varies the gain of the current/voltage converter inversely as the level of the measured current reaches each of a plurality of successively increasing discrete current levels. The output of the current/voltage converter is multiplied by the line voltage which is detected by a potential transformer with the output of the multiplier being coupled to an analog-to-pulse rate converter. The analog-to-pulse rate converter generates a pulse train having a pulse rate which is proportional to the product signal at the output of the multiplier. A means responsive to the output of the current transformer incrementally varies the pulse rate of the pulse train as the measured current reaches each of the successive plurality of discrete current levels so that the pulse rate varying means compensates the variance of the gain of the current-to-voltage converter. Thus, a watt-hour meter is provided which has a substantially constant gain and an exceedingly large dynamic range.

An Automatic RMS/DC Comparator

Abstract: The design of an instrument for the automatic comparison of an ac voltage with a stable dc source is described. A differential multijunction thermal converter is used as an rms/dc converter with an FET-switched input amplifier for ac/dc substitution. The output voltages of the rms/dc converter with ac and dc input voltages are sampled and stored, and the difference amplified and displayed on a panel meter or chart recorder. Accuracy is ±20 ppm of input ranges of 10-200 V at frequencies of 50 Hz-1 kHz, and maximum full scale deflection sensitivity is 0.01 percent of input range. The instrument may be used either as an rms comparator with a linear voltage scale or as a mean-square comparator with a linear power scale.

DC-DC converter in watch system

Abstract: A solid state watch having a DC to DC power converter responsive to timekeeping signals for powering a liquid crystal display. The power converter comprises a one-shot multivibrator responsive to an oscillatory timing signal from the timekeeping circuitry for generating a series of one-shot pulses having controllled width. A switching regulator is coupled to the one-shot multivibrator and converts a relatively low DC supply voltage into a relatively high DC output voltage in response to the oscillatory input signal. The switching regulator has temperature compensating feedback for compensating the output of the regulator in accordance with liquid crystal display characteristics with respect to ambient temperature changes.

Variable frequency power converter for ac motor drive

Abstract: In a variable frequency power converter of a current type for driving an AC motor including a rectifier, an inverter, and a smoothing reactor disposed on a DC transmission line between the rectifier and the inverter, there are provided a series circuit having a switching circuit and a smoothing capacitor on the DC input side of the inverter and a feedback circuit having controlled rectifier elements and commutation reactors for feeding back the reactive power of the AC motor. The power converter operates as a current type converter until the output frequency of the converter reaches a predetermined value under the condition that the switching circuit and the controlled rectifier elements are non-conductive, and operates as a voltage type converter when the output frequency has reached the predetermined value under the condition that the switching circuit and the controlled rectifier elements are conductive.

Regulated AC to DC converter having a controllable rectifier assembly

Abstract: An output-regulated AC to DC converter has a rectifying stage including a plurality of thyristors each shunted by a diode of opposite polarity. The excitation of a coil disposed between an input transformer of the converter and the rectifying stage is controlled by selectively varying the thyristor conduction patterns so that the output DC voltage may be added to or subtracted from the transformer output voltage, depending on the sense of deviation of the actual coil current from a reference coil current. Such reference current, in turn, is derived as a sinusoidal quantity whose phase is coincident with that of the AC input voltage to the converter and whose amplitude is proportional to the difference between the DC output voltage of the converter and a desired value.

Wide-range logarithmic responding translation circuit

Abstract: The disclosed circuit provides a wideband, wide-range logarithmic responding voltmeter particularly suitable for use as a transducer analyzer The circuit includes an input for receiving a given AC input signal which can vary within a 100 db dynamic range The input signal is coupled to a buffer amplifier the output of which is capacitively coupled to a logarithmic converter The converter includes an operational amplifier and provides an AC output signal which is proportional to the logarithm of its AC input signal The open loop gain of the operational amplifier is utilized to provide the AC output signal The output signal of the converter is capacitively coupled to a precision AC/DC converter which rectifies and filters the output signal to provide a DC output voltage the level of which is, therefore, also proportional to the logarithm of the given AC input signal within its 100 db range The DC output voltage is coupled to utilization means such as a logarithmically calibrated chart recorder or meter The precision AD/DC converter also includes a zero-adjustment for nulling any offsets in its circuit and any residual noise at the output of the logarithmic converter Accordingly, with no input signal applied to the disclosed circuit the output recorder and/or meter stably read exactly zero ("0")

Variable duty cycle balanced DC/DC power converter

Abstract: A balanced DC/DC power converter employs a transformer in combination with a simplified arrangement for generating variable duty cycle pulses to deliver a load voltage which may be greater or less than the power supply voltage.

Frequency limited ferroresonant power converter

Abstract: A transformer in combination with a push-pull transistor switch forms the inverter of a DC to DC converter. Feedback from the rectified output of the transformer ferroresonant winding controls the inverter frequency. A controllable current source solely responsive to a signal derived from the converter output voltage controls the charging of a timing capacitor which upon reaching a threshold value causes termination of each inverter half-cycle. The current source includes a clamping device operative to limit the inverter frequency to a region where effective negative feedback regulation is maintained.

Single phase 3-wire electronic electrical energy meter

Abstract: Metering kWh in a single phase, 3-wire, FL Hertz a.c. electrical system is accomplished by detecting the current flow in two lines of the three-wire system by means of a current transformer having two primary windings and a single secondary winding. The voltage in the system is detected by means of a potential transformer having the primary windings thereof connected across the load impedances and having the secondary thereof connected to a pulse width amplitude modulated multiplier. The multiplier derives a signal which is proportional to the current in the system and the detected voltage across the load impedances thereof. The output of the multiplier is converted to a d.c. voltage which is proportional to the total average power consumed by each of the load impedances with the d.c. average power voltage being converted to a pulse train by an analog-to-pulse rate converter. Thus the output of the analog-to-pulse rate converter is a series of output pulse signals having a variable signal repetition rate f proportional to the average power with each pulse signal representing a constant or quantized amount of electrical energy. A counter or register performs conventional accumulation storage and display functions in response to the series of output pulses delivered thereto from the analog to pulse rate converter.

Ferroresonant power converter with controll of inverter frequency and sensing of saturation condition

Abstract: A transformer in combination with a push-pull transistor switch forms the inverter of a DC to DC converter. Feedback from the rectified output of the transformer ferroresonant winding controls the inverter frequency. A controllable current source responsive to a signal derived from the converter output voltage controls the charging of a timing capacitor which, upon reaching a threshold value, causes termination of each inverter half-cycle. A capacitor discharge arrangement is included to ensure continuity of inverter frequency under light load conditions when inverter half-cycle termination results from transformer saturation.

Input signal powered converter

Abstract: Input signal powered converter apparatus comprises A. A SIGNAL SOURCE TO PRODUCE AN ANALOG OUTPUT CURRENT, B. CONVERTER MEANS RESPONSIVE TO THE SOURCE OUTPUT CURRENT TO PRODUCE AN OSCILLATORY OUTPUT SIGNAL WHICH VARIES AS A LINEAR FUNCTION OF THE SOURCE OUTPUT CURRENT, C. A DETECTOR RESPONSIVE TO SAID OSCILLATORY OUTPUT SIGNAL, AND D. CIRCUITRY COUPLED BETWEEN THE SOURCE OUTPUT AND THE CONVERTER MEANS TO ELECTRICALLY ENERGIZE THE CONVERTER MEANS IN RESPONSE TO CURRENT SUPPLIED BY THE SOURCE OUTPUT.

Nonsaturating asymmetric dc/dc converter

Abstract: A DC converter including a transistor switch and a transformer having first and second windings connected so that the transistor passes asymmetrical current pulses to the first winding. When the switch opens, asymmetrical current pulses again pass through the first winding and through a gating circuit connected thereto. The instantaneous voltage across the second winding is used as the drive voltage for the transistor switch to prevent transformer saturation.

DC to DC converter for producing two individually controlled and stabilized DC-voltages

Abstract: A DC to DC converter which gives two individually controlled and stabilized DC voltages includes an oscillator of the push-pull type and two rectifiers which are connected to the output of the oscillator. The transformer of the oscillator has a primary winding which has been split up in two halves, the end of each half being connected to a controlling DC voltage. The secondary winding of the oscillator transformer has its one end connected to the two rectifiers. The output of each of the rectifiers is connected to one input of a regulating circuit, the output of which is connected to each of the primary winding halves for delivering the controlling DC voltage.

Voltage monitor and control circuit

Abstract: A circuit for the monitoring and control of a DC to DC regulated power supply furnishing regulated voltage to a load. The output of the power converter is ultimately used to control a pair of shunting transistors which control the switching transistors in the power converter.

Constant speed regulator for DC motor

Abstract: In a constant speed regulator for a DC motor of the type in which the output of a generator mechanically coupled to a DC motor is converted into a square waveform output whose pulse duration or width is constant but whose duty cycle varies in response to the rotational speed of the DC motor, and the square waveform output is integrated so that the rotational speed of the DC motor may be controlled in response to the integrated output, an improvement comprising a series-circuit of a capacitor and a resistor connected between the output terminal of an integrator and the DC motor and a constant voltage circuit or a constant voltage regulating circuit shunting a DC power source, thereby eliminating the ripple component in the output of the integrator.

DC to DC converter with linear pulse processing circuitry

Abstract: A DC to DC converter has a dual mode current and voltage regulation circuit and monitoring and metering circuits responsive to digital type control pulse signals The regulation feedback circuitry is responsive to the relative priorities of the respective control pulse signals The digital type control pulse signals are generated by modulating circuits in response to sensed converter signals with a time delay relative to a common synchronizing pulse The time delay is a linear function of the sensed converter signal The modulating circuits include feedback circuitry to render the percentage time delay of the time delayed pulse invariant with respect to the time frame of each pulse irrespective of variations in the frequency of the common synchronizing pulse and other timing errors in the converter circuit

Dynamic rms converter

Abstract: A signal measuring means to provide a DC voltage that is proportional to the root-mean square (RMS) value of the input signal.

Automatic turn-on circuit for a DC to DC down converter

Abstract: A DC to DC down converter having a semiconductor switch connected between the input and output terminals thereof, which switch is controlled by a variable pulse generator and an automatic turn-on circuit including a voltage divider connected between the input and output terminals of said converter, switching means operable in response to a voltage across said voltage divider and controlling the application of power to the variable pulse generator, and a diode connected between the semiconductor switch and the junction of the voltage divider and output terminal to allow the converter to shutdown when the load is removed from the output terminal.

Automatic ac/dc rms comparator

Abstract: This invention is directed to an improved apparatus for the accurate comparison of an ac voltage with an accurate dc voltage standard to obtain the RMS value of the ac voltage. The voltages are alternately applied to the first heater of a differential multijunction thermal converter. The voltage generated by the converter is applied to a feedback circuit which includes a series connected amplifier, integrator and inverter and wherein the sum of the amplifier and inverter outputs is applied to the second heater in the converter. A pair of sample-and-hold circuits are alternately connected to the inverter output such that they obtain dc voltages representative of the ac and dc voltages respectively. The difference between the representative dc voltages is applied to a zero-centre meter or recorder.

A DC-DC Converter for Radiation Monitors

Abstract: To provide supply voltages for a detector and electronic circuits is a problem which frequently arises in designing a radiation monitor. With portable assemblies, which use primary or secondary batteries, this problem must bo solved by using DC-DC converters. In general, for each supply voltage a separate DC-DC converter may be used, but in some cases a single converter can produce two or more output voltages. The DC-DC converter should have high efficiency and stable output voltage. The two principal reasons for which the output voltage might change its value are the changes of the batteries voltage and of the converter load. The converter which will be described here can stand very large variation of the batteries voltage and produces two output voltages, one for electronic circuits of the monitor, and the other for its GM counter.

DC voltage regenerating transformer coupling device

Abstract: A high speed and highly accurate transformer coupler comprising a pulse transformer to the input winding of which a DC voltage source is connected in which when a DC voltage is needed to be regenerated, the output winding of the pulse transformer is supplied with such a pulse voltage as enabling the voltage induced on the input winding by the pulse voltage on the output winding to become higher than the DC voltage to generate on the output winding a voltage proportional to the DC voltage.