Showing papers on "Flyback converter published in 1976"

Voltage boost circuit for DC power supply

Abstract: A typical "stand alone" precision power DC to AC solid state converter reres a higher DC supply voltage than is usually available from its utility power sources. The disclosed invention is a voltage boost circuit that provides the DC-bus voltage amplitude for precision power DC to AC solid state converters by transforming only the difference between the available raw power DC voltage bus and the required precision DC voltage amplitude. This DC voltage difference obtained by the circuitry of this invention is boot-strapped to the available DC bus to obtain the required precision DC voltage.

Communication system interface circuit

Abstract: A communication system includes a mobile station, a plurality of base stations and a central terminal. Each base station converts RF signals from the mobile station to AF signals. The AF signals are carried over a balanced line to the central terminal. Each base station generates a DC voltage signal whose level is representative of the level of its received RF signal. The central terminal includes means to monitor DC current levels, from each base station, on the balanced line and select that base station producing the highest DC current. The unique interface circuit senses the base station generated DC voltage, which is referenced to a fixed ground potential, and produces a corresponding current which is referenced to a floating ground potential. This current is then coupled to the balanced line for transmission to the central terminal. The interface circuitry includes a DC to AC converter which converts the DC signal voltage to an AC signal. This AC signal is capacitively coupled to an AC to DC converter which generates a corresponding DC voltage. The final stage is a transconductance circuit which produces an output current presenting the DC voltage level generated by the AC to DC converter. In this manner, a ground referenced voltage is transformed to a floating ground reference current suitable for transmission down a balanced line.

Malfunction detecting apparatus for use in a CRT deflection circuit

Abstract: Apparatus is provided for preventing the generation of an excessively high voltage by the high voltage circuit of a CRT device, such as a television receiver, thereby avoiding the danger of producing injurious X-ray radiation and further minimizing the potential fire hazard attributed to such an excessively high voltage. A flyback transformer is connected to a resonant capacitor and is driven by a switching device synchronized with horizontal scanning pulses so that flyback pulses are produced during the normal retrace intervals in the horizontal deflection. A relatively low voltage power supply is coupled to the switching device to apply an operating voltage thereto. A first detecting circuit is coupled to the flyback transformer for detecting a high frequency component included in the flyback pulses in the event of a malfunction of the resonant capacitor, such as a disconnection of that capacitor, which high frequency component causes an excessively high voltage to be produced by the high voltage circuit. A second detecting circuit is coupled to the flyback transformer for detecting a high flyback pulse level that is produced when the operating voltage applied by the low voltage power supply exceeds a predetermined level. In the event that the first detecting circuit detects the presence of a high frequency component or the second detecting circuit detects a high flyback pulse level, a switch is actuated to control the CRT deflection circuit, thereby reducing the level of the flyback pulses, and thus the level of the high voltage produced by the high voltage circuit.

The venable converter: a new approach to power processing

Abstract: A regulating DC-to-DC converter is described which utilizes a new circuit configuration to achieve several desirable features including higher efficiency, a single circuit for regulation and conversion, minimized output filter requirements and simplified control system applications. The DC operating characteristics are derived and the efficiency of the new ocnverter is shown to compare favorably with the conventional boost regulator. An AC model is derived and a comparison is made between analytical and experimental results.

Naturally commutated voltage-fed converter for linking a DC source to an AC system

Abstract: A naturally-commutated, voltage-fed direct-current (DC) to alternating-current (AC) power converter employing thyristor elements couples a DC power system with an AC power system without the requirement to force commutation. To effect natural commutation, the fundamental component of current flowing between the DC system and the AC system must lead the DC system switching voltage.

Dc voltage converter and shock-type high voltage utilization

Abstract: A DC voltage converter includes an oscillator that converts a DC battery voltage to an oscillating voltage, a low voltage transformer that increases the oscillating voltage to a higher oscillating voltage, and a voltage rectifying-capacitor charging network that increases the higher oscillating voltage to yet a higher DC voltage at an output terminal for DC high voltage utilization devices and the like An electric switch portion is selectively actuated by the user to apply the battery voltage to the oscillator, resulting in the generation of the stepped-up DC voltage at the output terminal Utilization devices for the voltage developed by the converter shown are a miniature animal training device and a cattle prod device The miniature animal training device has a pair of outwardly projecting electrodes mounted on a side at one end of the housing that is sized and shaped to fit within and conform to the palm of a hand The batteries, converter and electric switch portion are contained in the housing whereby the device produces a stepped-up DC voltage at said output terminal upon the depression of one of the electrodes as both electrodes are pressed against an object to be electrically shocked The cattle prod device has a pair of electrodes mounted on the end of a housing assembly made up of telescoping tubular housing sections with one housing section containing the batteries, converter and electric switch portion whereby the pressing of the electrodes against an object to be shocked causes a shock of the object The housing assembly is releasably supported by a rigid handle or an extensible handle assembly

Emission standards and design techniques for EMI control of multiple DC-DC converter systems

Abstract: Radiated and conducted emission standards are derived for each converter in a multiple DC-DC converter system, allocated as a function of power rating. Analytical methods of predicting the emission and design techniques for achieving the standards are described. Recommended procedures and test equipment used to determine the actual emission level of each converter are also described.

Unipolar wide-range current-to-frequency converter

Abstract: In a unipolar version of an analog-to-digital converter of low-level signals involving a self-zeroing current-to-frequency converter, which virtually eliminates the effects of voltage offsets at the input to the converter while avoiding large leakage currents, improved circuitry is provided in order to avoid paralysis of the converter which could be caused by small input currents or charges of polarity opposite to that of the normal signal current or by drifts in the converter input voltage which produce a negative-charge offset. The circuitry includes provision for the automatic introduction at the converter input of a relatively-large restoration current with the same polarity as the signal current, and this current can also be used for converter checking and calibration. One version of this circuitry involves exposing a junction diode at the converter input to light, causing it to act as a photodiode. One easily controlled source of such light may be a light-emitting diode conducting a suitable current placed in close proximity to the junction diode within the same enclosure. When the junction diode forms a part of a secondary feedback loop used during the discharge period of a primary capacitive feedback, then exposing it to light speeds up the secondary feedback, thereby reducing converter dead time. Other devices may be used for current introduction at the converter input, including a mechanical switch, but they are less preferable from the standpoint of leakage current, size and speed of response.

Regulation of a lightweight high efficiency capacitor diode voltage multiplier DC-DC converter

Abstract: A method for the regulation of a capacitor diode voltage multiplier dc-dc converter has been developed which has only minor penalties in weight and efficiency. An auxiliary inductor is used, which only handles a fraction of the total power, to control the output voltage through a pulse width modulation method in a buck boost circuit.

Efficient AC energy converter - has internal resistance of DC energy converter connected into AC circuit

Abstract: The ac energy converter has improved energy conversion efficiency compared with direct conversion systems such as thermocouples, thermionic valve diodes, photovoltaic cells, fuel cells, magnetohydrodynamic converters etc. To this end, the electrical internal resistance of a direct energy converter is connected into an a.c. circuit, and means are provided to ensure that the current flows through the internal resistance of the direct energy converter as rectified current, and that an impedance is provided in the a.c. circuit so as to limit the current. The impedance value is greater than the value or magnitude of the internal resistance of the direct energy converter, which is a laser diode.

Switching regulator with feedback system for regulating output current

Abstract: A switching regulator includes a chopper circuit and a DC-DC converter. A switching signal for use with the chopper circuit is derived from an inverter portion of the DC-DC converter so as not to use an external pulse oscillator. A DC voltage feeback circuit is provided from the output of the DC-DC converter to the chopper circuit so as to stabilize the DC output signal of the DC-DC converter.

Power saving circuit for use with a converter circuit in a telephone switching installation

Abstract: Power saving means is shown for use with a converter circuit in a telephone switching installation. The converter circuit comprises an analog-to-digital converter and a digital-to-analog converter. The voltage supply for the converter circuit is switched on only upon the appearance of analog signals to be converted into digital signals or digital signals to be converted into analog signals.

The biased transformer DC-to-DC converter

Abstract: A dc-to-dc converter design based on the constant-current flux-reset principle is presented. Such converters use a mulitude of separate individual half-wave switching sections. Each section consists of a power transistor and a transformer which is reset through an external bias current source. The transformer typically contains a square-loop core without an airgap. Center tap, SCR, and bridge-type configurations are presented attendant to single-phase full-wave, and polyphase operation. Transformer-core saturation dc ratcheting and cross conduction problems, which frequently plague dc/dc converters, are eliminated. As a result, considerable differences in conduction times between power transistors can be tolerated, as well as some overlap resulting from storage and recovery lags. Typical approaches, circuit variations, and tradeoffs are being presented. Detailed schematic diagrams of actual units for aerospace applications and for industrial uses are discussed in the Appendix.