Abstract: A current supply circuit for an electronic apparatus having standby, normal and economy modes of operation includes a remote control receiver which responds to a remote control signal from a remote control unit to select either mode of operation. A voltage source provides a main voltage which is detected to produce a switching voltage when the main voltage is present. The switching element of a voltage responsive switch is connected to a first input contact in the presence of the switching voltage and to a second input contact in the absence of the switching voltage. The output contact of the voltage responsive switch is connected to an input terminal of the remote control receiver and to a first input terminal of the filter.

Abstract: The switched-mode power supply comprises a secondary winding and four diodes for producing two rectified voltages of the same polarity, one of which can be regulated. A connection of the unregulated voltage has connected to it a variable Zener diode as an error amplifier for transmitting a regulating signal to the primary side. The driver stage provides a pulse-width-modulated square-wave signal for driving the switching transistor which is arranged at a high potential between the operating voltage on the input side and a first connection of the primary winding. The second connection of the primary winding is connected with a Zener diode and provides a stabilized voltage for the driver stage. Arranged between the driver stage and the control electrode of the switching transistor there is a differentiating element which produces positive and negative switching voltages for controlling the switching transistor.

Abstract: In a switch-mode power supply, a transformer is used to transmit power during the forward-sweep time. The transformer is also used to transmit a control or regulating variable during the flyback time.

Abstract: A line deflection circuit for a television receiver or a switched-mode power supply operate with a switching transistor that is connected in series with the primary winding of a transformer and is periodically switched on and off by a switching voltage. In such a circuit, appreciable turn-on and turn-off losses, which reduce the overall efficiency of the circuit, are produced at the switching transistor, particularly at higher operating frequencies. Within a control circuit a DC voltage source is connected to the base of the switching transistor via a periodically actuated switch element and a coil having a core and a tap. The two parts of the coil are wound in opposite senses, and the tap is connected via a diode to ground or to the emitter of the switching transistor.

Abstract: In a plasma display screen them is a circuit which alternately applies a positive and negative voltage to the general capacitance of the screen or panel for a reset process. In the current path there is an inductance to ensure the recovery of the energy to the total capacity. The aim is to improve the drive and the erase process of a pixel in such a circuit The capacity (Cp) is cyclically connected via a third switch (T3) to such a third operating voltage that the voltage (UCp) at the capacitance (Cp) has a period of zero voltage between those of positive and negative voltage. Especially for a control circuit for a plasma display screen for a television receiver.

Abstract: Switch mode power supplies produce a brief pulse-like load on the mains and have a high harmonic content. Such a high harmonic load on the mains is undesirable. There are increasingly strict regulations for the level of harmonic loads connected to the mains. The present switch mode power supply includes a series circuit formed by an inductor and a diode connected between a charge capacitor, which is dimensioned to be relatively small, and a pickoff of a primary winding of a transformer of the switch mode power supply. A relatively large energy storage capacitor connected to the primary winding is decoupled from the charge capacitor by a second diode. The series circuit produces an additional charging current, which extends the current which is drawn from the mains during one half cycle of the mains voltage, and reduces the amplitude of the current.

Abstract: In a switch mode power supply which includes a transformer for DC isolation and a switching transistor, a control transistor which controls the switching transistor is switched on by an appropriate control voltage during the isolating phase until the collector voltage of the switching transistor has fallen to a minimum. The control transistor is preferably switched on during the isolating discharge time and the subsequent oscillation phase of the transformer.

Abstract: This invention relates to a process and a device for controlling power for a circuit comprising a resonant inverter intended to supply a variable impedance load comprising an inductive component. The invention renders the active power consumed by the load independent of the nature of the load by producing an error signal that is a function of an average value of a current passing through power transistors of the inverter, this error signal being used to control a power modulator controlling the switching of the power transistors. Such a process and device finds particular application to a circuit for controlling power supplied to an inducer and a cooking utensil.

Abstract: The static frequency converter controlled by a control parameter processing and command generation element includes an active filter at the terminals of a dc/dc converter powering a load, wherein the active filter includes an inductance (L1) in series with a diode (D1) grounded through a condenser (C0) and a switch (K5) controlled by the control parameter processing and command generation element and that the dc/dc converter includes at least one complete bridge, one of the arms of which has two condensers (C1,C2) and the other arm has four switches (K1. . . K4). This converter can be used with all load types that can be controlled by frequency converters, and more particularly to a transformer type inductive load or alternating electric motors, with or without commutators, and particularly to single phase and multiphase asynchronous motors.

Abstract: In a television receiver, having the ability to display differing image formats, the image width is capable of being continuously adjustable in the manner of a zoom effect. The ability to continuously adjust the image width is accomplished without any perceptible effect on the horizontal scan output. In that circuit, a tangent capacitor is coupled to a second capacitor with a switch being connected for switching the second capacitor into and out of the circuit. The switch is closed for an adjustable period beginning at the line center.

Abstract: A switch mode power supply includes a transformer and a switching transistor for turning the primary of the transformer on and off. The secondary of the transformer is connected to a comparator which compares the output voltage to a reference voltage and provides a reverse current to the switching transistor to control the duty cycle of the switching transistor in accordance with the comparison.

Abstract: It is known to provide a large screen area using a picture tube having a plurality of guns. The object is to provide a transition of continuous brightness, so that the partial picture transitions are no longer perceptible.This is achieved in that a picture tube without a shadow mask, but with optical sensors, index regions and optical walls is employed, so that a precise detection of the beam is possible and the partial picture transitions are no longer perceptible.Especially for television receivers and monitors.

Abstract: A line-powered phase-control circuit includes a source of rectified voltage. An inductance is responsive to the rectified voltage. A switching transistor has a conduction path connected in series with the inductance at a junction. One plate of a charging capacitor is connected to the inductance and the rectified voltage charges the charging capacitor through a first diode. A switch mode power supply includes a transformer having a primary winding connected between the junction and the plate of the charging capacitor. A second diode is connected between the inductance and the junction.

Abstract: An inductive cooking device for reducing disturbance radiation has a shielding housing with an opening in the region of a cooking (hot) plate containing an induction coil. A further coil, the ends of which are connected by a capacitor, is provided in the region of the opening.

Abstract: A switching power supply includes a switching transistor coupled to a winding of a first transformer for generating a collector current. The collector current is coupled in a current path that includes that winding and a primary winding of a power transformer. The collector current is coupled to the base of the switching transistor via the first transformer such that when the switching transistor is conductive, both the collector current and a base current of the transistor are upramping. When the transistor is nonconductive, a horizontal synchronizing signal is coupled via the first transformer to synchronize the base current.

Abstract: A switched mode power supply operating with current mode regulation comprises an output switch coupled to a first winding of a transformer and to a source of input supply voltage. The switch is responsive to a control signal for initiating a pulse width modulated pulse voltage in a second winding of the transformer. A supply circuit coupled to the second winding generates an operating voltage. A feedback signal source monitors both current flowing through the first winding and the operating voltage. A control circuit coupled to the feedback signal source includes an oscillator for generating the control signal at a substantially constant frequency during normal operation and at a variable frequency during abnormal operation. The control circuit is responsive both to the current and to variations of the operating voltage over a regulating range, in a negative feedback loop. The control signal varies the on-time conduction of the output switch in each cycle to stabilize the operating voltage.

Abstract: A line deflection circuit for a picture tube, for generating a symmetric deflection current in a deflection or sweeping coil and a tangential capacitor comprises: an active switch for supplying a near square wave shaped output voltage to one end of the deflection coil, at half line frequency and at a keying ratio of 1:1; and, an amplifier having an output coupled to the other end of the deflection coil and having a control input responsive to at least one of first and second corrective variables to assure linearity of a deflection current flowing through the deflection coil and line centered zero crossing of the detection current. The first corrective variable is proportional to the deflection current through the deflection coil and the second corrective variable is related to a deviation of the output of the switch from the square wave shape. The circuit may also comprise a timing comparator for determining each zero crossing relative to immediately preceding and following edges of the output voltage.

Abstract: A switching power supply in which a regulating voltage generated on the secondary side of the circuit is transferred to a control circuit on the primary side of the circuit so as to stabilize the dc operating voltages produced on the secondary side. In order to avoid the dangers involved from the absence of such regulation, a further or emergency regulating voltage is generated on the primary side of the circuit and if the regulating voltage from the secondary side is absent, the system is automatically switched to the further regulating voltage generated on the primary side, which further regulating voltage regulates the operating voltages to at most the rated values and preferably to values that are reduced by up to 10%.

Abstract: In a switched mode power supply, an output switch is coupled to the primary winding of a transformer and to an input supply voltage derived from the AC mains voltage. A driver stage is coupled to the output switch and to a switched control voltage for producing on-off switching of the output switch between conduction and cutoff to generate a pulse voltage in a secondary winding of the transformer. A supply circuit including a rectifier is coupled to the pulse voltage for generating an operating voltage. A control circuit, responsive to the feedback of the output voltage, modulates the control voltage in a manner that varies the on-off switching of the output switch to stabilize the operating voltage. A bias voltage, derived from the AC mains voltage, and available during a startup interval of the power supply, is coupled to the driver stage during the startup interval.

Abstract: An inverter circuit for driving a load including an inductive component such as an inductive cooking appliance, and being powered by a pulsating DC source obtained by rectifying a single phase AC power input. The inverter includes a pair of power transistors operating in a push pull mode with a multiple winding transformer, and operating at a frequency in excess of the AC power line frequency. Alternate switching of the power transistors is fed back through the transformer to control the switching of the transistors. The improved circuit provides positive switching of the power transistors at the higher frequencies regardless of the fluctuations in amplitude of pulsating DC power input, by triggering the generation of constant firing pulses from a fixed voltage source to the transformer windings in a feedback arrangement. A starting oscillator is also provided to initially start, or restart, the inverter; and the starting oscillator is automatically decoupled from the inverter when the inverter is operating.