Showing papers on "Flyback converter published in 1974"

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.

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.

Solid state flyback transformer checker

Abstract: An instrument for providing information concerning the condition of a horizontal output transformer in a television set

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.

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.

Stabilizing network for crt high-voltage power supply

Abstract: A high d-c voltage for the operation of a television picture tube is derived from the rectified output voltage of a transformer developed across a secondary winding thereof, this transformer having a primary winding periodically energized by the flyback stroke of an associated horizontal-sweep circuit. A part of the flyback current also passes an ancillary transformer winding in series with a resonant network normally tuned to the fifth harmonic of the fundamental frequency of the flyback pulse to level the output voltage as long as the transformer secondary is substantially open-circuited, i.e., in the absence of anode current generated by the beam; this secondary is connected to the input of a transistor generating a biasing current through a control winding electromagnetically coupled with the inductance of the resonant network so as to detune same in the presence of a substantial anode current, thereby increasing the primary current of the transformer to compensate for the added drain upon the high-voltage transformer output.

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.

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.

Flyback eht and sawtooth current generator

Abstract: A flyback EHT- and sawtoothcurrent-generator using a transformer and switching means connected thereto which conduct during a scan period and do not conduct during a flyback period, and partly parasitic reactances connected to the transformer. During the flyback period the generator has at least two resonant frequencies so chosen that a substantially oscillation-free scan is produced and during the scan it has at least one resonant frequency which is approximately equal to an integral multiple of the reciprocal value of the duration of the scan period.