Abstract: For achieving a desired course in the demagnetizing circuit (I1) and power dissipation that is as low as possible during continuous operation of a color television set, a demagnetizing circuit for controlling the demagnetizing current (I1) includes two transistors (T1, T2) that are controlled via a common or via two separate capacitive voltage dividers (C1-C4). A rectified alternating voltage is applied to the capacitive voltage dividers (C1-C4). The demagnetizing current (I1) controlled by the transistors (T1, T2) is supplied to a demagnetizing coil (R4).

Abstract: To start a switching power supply in an energy saving manner, the method and device according to the invention transmits the energy that is collected by the Y-capacitors through a diode to a capacitor that is located on the secondary side. Once the voltage in the capacitor reaches a first predefinable minimum value, the voltage is applied to an impulse generator as an input voltage and the generator starts the switching power supply. Once the voltage in an additional capacitor on the secondary side reaches a second predefinable minimum value, the voltage in the capacitor is also applied as an input voltage to a control unit, preferably, a microprocessor, that controls the impulse generator.

Abstract: For achieving a desired course in the demagnetizing circuit (I1) and power dissipation that is as low as possible during continuous operation of a color television set, a demagnetizing circuit for controlling the demagnetizing current (I1) includes two transistors (T1, T2) that are controlled via a common or via two separate capacitive voltage dividers (C1-C4). A rectified alternating voltage is applied to the capacitive voltage dividers (C1-C4). The demagnetizing current (I1) controlled by the transistors (T1, T2) is supplied to a demagnetizing coil (R4).

Abstract: A method for driving a switch in a switched-mode power supply, in which the switch is connected in series with a primary coil of a transformer and in which a control signal dependent on an output voltage is available. In this case, reference instants at which a voltage present across the switch corresponds to a first reference voltage value or at which a voltage present across the primary coil corresponds to a second reference voltage value are detected and counted, the switch being closed again only after the number of detected reference instants has reached a comparison numerical value. The invention furthermore relates to a switched-mode power supply for realizing the method according to the invention.

Abstract: A method for regulating a switched-mode power supply includes steps of: providing a switched-mode power supply having at least one electronic switch and a drive circuit having an input receiving a primary current simulation, the switched mode power supply supplying a relatively higher output power at times and a relatively lower output power at other times; as an output load decreases, lowering a switching frequency to reduce switching losses; and starting the step of lowering the switching frequency during an occurrence of the lower output power by, during a switch-on interval of the electronic switch, deforming a rise in a voltage at the input for receiving the primary current simulation such that the voltage rises more steeply during a time segment.

Abstract: To start a switching power supply in an energy saving manner, the method and device according to the invention transmits the energy that is collected by the Y-capacitors through a diode to a capacitor that is located on the secondary side. Once the voltage in the capacitor reaches a first predefinable minimum value, the voltage is applied to an impulse generator as an input voltage and the generator starts the switching power supply. Once the voltage in an additional capacitor on the secondary side reaches a second predefinable minimum value, the voltage in the capacitor is also applied as an input voltage to a control unit, preferably, a microprocessor, that controls the impulse generator.

Abstract: A method for driving a switch in a switched-mode power supply, in which the switch is connected in series with a primary coil of a transformer and in which a control signal dependent on an output voltage is available. In this case, reference instants at which a voltage present across the switch corresponds to a first reference voltage value or at which a voltage present across the primary coil corresponds to a second reference voltage value are detected and counted, the switch being closed again only after the number of detected reference instants has reached a comparison numerical value. The invention furthermore relates to a switched-mode power supply for realizing the method according to the invention.

Abstract: In order to achieve complete short-circuit protection irrespective of a location of a short-circuit in a switched-mode power supply having a controllable switch in a primary circuit, the controllable switch is opened when a voltage drop across an electrolytic capacitor in a primary circuit falls below a threshold value which can be predetermined. For this purpose, a capacitive voltage device containing two capacitances is connected in parallel with the electrolytic capacitor. A potential at a center tap of the capacitive voltage divider is compared in a comparator with a reference voltage, which opens the controllable switch when the potential at the center tap falls below the reference voltage.

Abstract: A method for regulating a switched-mode power supply includes steps of: providing a switched-mode power supply having at least one electronic switch and a drive circuit having an input receiving a primary current simulation, the switched mode power supply supplying a relatively higher output power at times and a relatively lower output power at other times; as an output load decreases, lowering a switching frequency to reduce switching losses; and starting the step of lowering the switching frequency during an occurrence of the lower output power by, during a switch-on interval of the electronic switch, deforming a rise in a voltage at the input for receiving the primary current simulation such that the voltage rises more steeply during a time segment.

Abstract: The invention relates to a switched mode power supply, whereby the number of components is reduced to a considerable extent in comparison with conventional switched mode power supplies. The switching transistor of the switched mode power supply is controlled by a processor on the secondary side of said switched mode power supply. Control thereof is determined by the software of the processor and can be slightly modified and adapted. The required processor functions can be taken over by a processor that is already contained in the device which is powered by the switched mode power supply.

Abstract: For achieving a desired course in the demagnetizing circuit (I1) and power dissipation that is as low as possible during continuous operation of a color television set, a demagnetizing circuit for controlling the demagnetizing current (I1) includes two transistors (T1, T2) that are controlled via a common or via two separate capacitive voltage dividers (C1-C4). A rectified alternating voltage is applied to the capacitive voltage dividers (C1-C4). The demagnetizing current (I1) controlled by the transistors (T1, T2) is supplied to a demagnetizing coil (R4).

Abstract: The invention relates to a switched mode power supply, whereby the number of components is reduced to a considerable extent in comparison with conventional switched mode power supplies. The switching transistor of the switched mode power supply is controlled by a processor on the secondary side of said switched mode power supply. Control thereof is determined by the software of the processor and can be slightly modified and adapted. The required processor functions can be taken over by a processor that is already contained in the device which is powered by the switched mode power supply.

Abstract: In order to achieve complete short-circuit protection irrespective of a location of a short-circuit in a switched-mode power supply having a controllable switch in a primary circuit, the controllable switch is opened when a voltage drop across an electrolytic capacitor in a primary circuit falls below a threshold value which can be predetermined. For this purpose, a capacitive voltage device containing two capacitances is connected in parallel with the electrolytic capacitor. A potential at a center tap of the capacitive voltage divider is compared in a comparator with a reference voltage, which opens the controllable switch when the potential at the center tap falls below the reference voltage.

Abstract: An apparatus for supplying a DC voltage to a load which can be connected to output terminals. The apparatus has a semiconductor switching element for a clocked application of a supply voltage to a primary of a transformer on the basis of a sequence of driving pulses applied to a control input of the semiconductor switching element. A driving circuit is provided for producing driving pulses. The driving circuit has a first input terminal for receiving an analog load-dependent control signal which is produced by a measuring configuration and governs a duration of the individual driving pulses. The driving circuit also has a second input terminal for receiving a starting signal defining turn-on instants of the driving pulses. The apparatus further has a pulse generator with an output terminal, connected to the input terminal of the driving circuit, for providing the pulsed starting signal on the basis of a control signal.

Abstract: A circuit arrangement is provided that is suitable for determining the output power of switched-mode power supplies. A charge capacitor is charged with a constant current for the duration of the discharging time of a transformer. The voltage across the charge capacitor is integrated by a downstream integration element. The output voltage of the integration element is proportional to the mean power of the switched-mode power supply. The inventive circuit arrangement takes into consideration that the charging and discharging times of the transformer can be different for different switching frequencies of the switched-mode power supply, even when the power output of the switched-mode power supply is the same.

Abstract: The switched-mode power supply has a transformer with an E-shaped core. Each side limb of the core is surrounded by a winding. The flow of current through the secondary winding is controlled by the output voltage to be regulated. A control signal for controlling the switching frequency of the power supply is decoupled at the primary side winding. This makes it possible to dispense with an optical coupler which would otherwise be necessary.

Abstract: A switched-mode power supply includes a circuit device with which a primary side is fed by a significantly reduced rectified voltage derived from the AC mains power supply voltage, during a standby operating mode. A phase gating control configuration, a capacitive voltage divider or a step-down controller are preferably used therefor. Power consumption in the standby operating mode is reduced approximately in proportion to the square of the primary-voltage reduction factor.

Abstract: In a voltage converter for producing a controlled output voltage from an input voltage, particularly in an isolating-transformer switch-mode power supply, a digitally realized control circuit is provided. This circuit contains a counter apparatus whose counter state is compared with a digital comparison value derived from the output voltage to be controlled. The pulse-width-modulated driving of a switching element coupled with an inductive element is carried out dependent on the result of the comparison and on a signal indicating the state of demagnetization of the inductive element. By means of a further comparison value for comparison with the counter apparatus, a turn-on blocking voltage is produced for the switching element, in order to raise the switching frequency for standby operation.

Abstract: A switch-mode power supply has a control device with an input for a control voltage which is coupled to a secondary voltage and an output for controlling a transistor that is connected in series with a primary winding of a switch-mode power supply transformer. The control device additionally includes a device for inhibiting the switching transistor from switching on again when a control error that is formed in the control device is less than a reference value. The control signal input and the output of the control device are coupled through a coupling element having a low-pass filter characteristic. A switching-on pulse for the switching transistor is consequently superimposed on the control voltage, with a time delay. If the load to be supplied is small (standby mode), the switching of the switching transistor is inhibited until the switching-on pulse which is coupled to the control voltage has decayed. A stable switching frequency slightly above the audibility limit can be set for the standby mode.

Abstract: A blocking-oscillator switched-mode power supply for sinusoidal current consumption includes a transformer having a primary winding. A smoothing capacitor is connected to the primary winding. A bridge rectifier is connected to the smoothing capacitor. A semiconductor switching element is connected to the primary winding for the clocked application of an alternating voltage, being rectified by the bridge rectifier and smoothed by the smoothing capacitor, to the primary winding. A control device is connected to the semiconductor switching element for triggering the semiconductor switching element. A current pump is connected to the smoothing capacitor and to the bridge rectifier for receiving current from the bridge rectifier during a turn-on phase of the semiconductor switching element and outputting a charged current to the smoothing capacitor during a blocking phase of the semiconductor switching element.