Abstract: The switching DC-DC converter comprises an inductor, a diode, a transistor and an integrated control circuit with an output switch, the output switch and the diode being coupled to the inductor for providing a DC output voltage. The transistor is coupled with a current input to an input voltage, with a control input to a current input of the output switch, and with a current output to a current output of the output switch.

Abstract: The switching DC-DC converter comprises an inductor, a control circuit with an oscillator and an output stage, the output stage being coupled to the inductor, a diode coupled to the inductor, and a feedback loop for generating a stabilized output voltage. An output voltage of the output stage is coupled with an oscillator input of the control circuit, for example via an impedance, for synchronizing an oscillation cycle of the oscillator with a current pulse of the output stage.

Abstract: The switched mode power supply comprises an inductor, a switching transistor, a controller circuit coupled to the switching transistor, a rectifying means and a feedback regulation loop for providing a stabilised output voltage. It comprises further a protection circuit coupled to an output or input of a comparator of the controller circuit for providing an overvoltage protection in case of a failure of the regulation loop. The protection circuit comprises in particular an integrating circuit and a comparating circuit. In a preferred embodiment, an output of the protection circuit is coupled to a sense input of the controller circuit, for switching off the controller circuit immediately in case of a failure. In another aspect of the invention, the protection circuit comprises further a second comparator coupled to the first comparating circuit for the surveillance of the input voltage of the switched mode power supply, and for the detection of a short circuit of the inductor or the rectifying means.

Abstract: The circuit arrangement comprises a driver stage and a control circuit coupled to the control input of a switching transistor. The driver stage provides a switching voltage for the operation of the switching transistor, and the control circuit provides a shaping of the switching voltage in the sense of delaying the switching through of the switching transistor. The control circuit comprises in particular a control transistor, which is coupled a control input via a high pass filter to the output of the driver stage and with an current input to the control input of the switching transistor. The switching transistor is for example a MOSFET being used for switching on and off a capacitive load.

Abstract: The circuit arrangement has a mains connection, a mains switch with two switching contacts, a demagnetization coil and a switch-mode power supply, which contains a driver circuit for producing a control voltage for the switching transistor of the switch-mode power supply. A first switching contact of the mains switch is arranged between the mains connection and the demagnetization coil in order to switch the demagnetization coil on and off, and the second switching contact is connected to a supply or control voltage for the driver circuit, in order to switch off the switch-mode power supply. In consequence, a power factor coil can be used between the mains connection and the switch-mode power supply for power factor correction, without the mains switch being loaded by the inductance of the power factor coil.

Abstract: The driver circuit for driving a switching transistor comprises a driver transformer for driving the switching transistor and an output stage for driving the driver transformer, and an output of the driver circuit is used for providing also said switching voltage. The switching voltage is derived advantageously from the primary winding of the driver transformer. Preferably a terminal of the primary winding of the driver transformer is directly wired to the gate electrode of the MOS transistor.

Abstract: The power supply according to the invention has a first switched-mode power supply and a second switched-mode power supply, which is connected in parallel with the first, and with both switched-mode power supplies having power factor correction. In this case, the first switched-mode power supply has an active power factor correction circuit, for example with a current pump which contains a coil which is coupled to a primary winding of a transformer, and the second switched-mode power supply has a power factor coil (NS) in its power supply for power factor correction. Both switched-mode power supplies are in this case arranged in one appliance, in particular in parallel and downstream from a common mains switch. The active power factor correction in this case flattens the pulsed current flow, and the power factor coil shifts the phase of the pulsed current flow.

Abstract: The circuit arrangement has a mains connection, a mains switch and a switched-mode power supply which contains a power factor coil for power factor correction. In this case, the mains switch has two switching contacts, one of which is arranged in a supply line between the mains connection and the switched-mode power supply, and in this way switches the phase or neutral conductor of the 50 Hz line network off and on. The connections of the second switching contact are located in a voltage supply for the driver circuit of the switched-mode power supply, and the second switching contact switches the switching transistor in the switched-mode power supply off when the circuit arrangement is switched off, by its control voltage being switched off directly or indirectly. The switching contact of a relay is arranged in parallel with the first switching contact of the mains switch, and the control coil of this relay is connected to an output voltage of the switched-mode power supply.

Abstract: The power supply unit comprises a switched-mode power supply which has a transformer (TR1) with a primary winding (W1) and a multitude of secondary windings (W2, W3), a switching transistor (T1) which is coupled to the primary winding (W1) and a control circuit by means of which an output voltage (U2) from the switched-mode power supply can be stabilized on the flyback converter principle. The power supply also comprises a switching regulator (7) which is connected to a secondary winding (W3) which supplies a positive voltage (U3) when the switching transistor (T1) is in the switched-on phase. The output voltage (U4) which is produced by the switching regulator is used in particular for operation of a low-noise converter (LNB). In one preferred embodiment, the switched-mode regulator (7) is a step-down converter, and the secondary winding (W3) supplies a rectified output voltage (U4) via a rectifier means (D4), the value of which output voltage (U4) is preferably in a range from 25 to 50 volts.

Abstract: The high voltage supply for a picture tube comprises a high voltage transformer, which generates the anode voltage of the picture tube, and a high voltage module with a switched mode power supply for providing a grid voltage, which is higher than the anode voltage. The output of the high voltage transformer is coupled to the transformer of the switched mode power supply, for adding the output voltage of the switched mode power supply to the high voltage of the high voltage transformer. Preferably, the transformer of the switched mode power supply provides the high voltage isolation, and at least the high voltage part of the module including the transformer is potted with a resin. The high voltage module provides advantageously also an output for a connection to the anode of the picture tube, so that the module can be used with present high voltage transformers, without requiring any modification.

Abstract: The switched-mode power supply contains a transformer (TR), a switching transistor (T1) in series with the primary winding (WP) of the transformer (TR), and a damping network (DN) on the secondary side, which has a connection for a further secondary winding (W2) via which energy is transferred from this damping network, by way of example, to a charge-storage capacitor (C3) which is coupled to this secondary winding. The connection is advantageously produced via a rectifying element, for example a diode (D3), which is coupled after the rectifying diode (D5) for the second secondary winding (W2). In a further exemplary embodiment, the diode (D2) in the series circuit, which is connected in parallel with the rectifier diode (D1) for the first secondary winding (W1), is not coupled to the charge-storage capacitor (C1) for the first secondary winding (W1), but is likewise coupled to the charage-storage capacitor (C3) for the second secondary winding (W2).

Abstract: The power supply according to the invention has a first switched-mode power supply and a second switched-mode power supply (II), which is connected in parallel with the first, and with both switched-mode power supplies having power factor correction. In this case, the first switched-mode power supply has an active power factor correction circuit, for example with a current pump which contains a coil which is coupled to a primary winding of a transformer, and the second switched-mode power supply (II) has a power factor coil (NS) in its power supply for power factor correction. Both switched-mode power supplies are in this case arranged in one appliance, in particular in parallel and downstream from a common mains switch. The active power factor correction in this case flattens the pulsed current flow, and the power factor coil shifts the phase of the pulsed current flow.

Abstract: The high voltage supply for a picture tube (T) comprises a high voltage transformer (DST), which generates the anode voltage of the picture tube, and a high voltage module (M) with a switched mode power supply for providing a grid voltage, which is higher than the anode voltage. The output of the high voltage transformer (DST) is coupled to the transformer (TR) of the switched mode power supply, for adding the output voltage of the switched mode power supply to the high voltage of the high voltage transformer. Preferably, the transformer (TR) of the switched mode power supply provides the high voltage isolation, and at least the high voltage part of the module (M) including the transformer is potted with a resin. The high voltage module provides advantageously also an output (3) for a connection to the anode of the picture tube, so that the module can be used with present high voltage transformers, without requiring any modification.

Abstract: The circuit arrangement comprises a power supply unit with a first power supply only for the analogue signal processing part and for the control part of a respective device. For the digital signal processing part, a second, separate switched mode power supply is provided, which is switched off, when only the analogue signal processing part is active, and which is in operation, when the digital signal processing part is on. For switching on and off of the second switched mode power supply, the power supply comprises a switching circuit (18), which is coupled in a special embodiment to a control loop (15) on the secondary side, for switching off the second power supply at the primary side via a galvanic isolating means (14). The switching circuit is provided with a supply voltage (12VS) from the first power supply and receives the on/off command from the control part, e. g. a microprocessor.

Abstract: The battery-operated power supply unit, which comprises a switching transistor whose current terminals are connected in series with a battery, in the current path of the power supply unit, comprises a protective circuit, which is arranged across the current terminals of the switching transistor and evaluates the differential voltage across the switching transistor. The switching transistor is in particular a MOSFET with a parallel-connected internal diode. In the event of too high a differential voltage, the power supply unit or an appliance connected downstream is switched off, so that the switching transistor is not destroyed in the event of a fault.

Abstract: The driver circuit for driving a switching transistor comprises a driver transformer for driving the switching transistor and an output stage for driving the driver transformer, and an output of the driver circuit is used for providing also said switching voltage. The switching voltage is derived advantageously from the primary winding of the driver transformer. Preferably a terminal of the primary winding of the driver transformer is directly wired to the gate electrode of the MOS transistor.

Abstract: The protection circuit for a power supply unit comprises a switching stage, at which at least two output voltages to be monitored are connected, these voltages being isolated from one another by means of resistors. Arranged here in the connection path of the output voltages is a diode, which turns on and thereby triggers the switching stage in the event of a fault, when there is a drop in one of the output voltages. In this way, the switching stage provides information which acts on a control loop of the power supply unit, so that the power supply unit switches off. The protection circuit also includes a passive network with a resistor and a capacitor, which prescribes a time constant, after which the protection circuit permits renewed starting of the power supply unit. The switching stage may be realized, for example, by a transistor stage, which provides the information signal for the event of a fault for the power supply unit when turning on occurs.

Abstract: The protection circuit for a switch has an energy-storage means, which is connected to a control input of the switch and which is charged with a delay via resistance means when a control voltage is present and is discharged via switching means when the control voltage is low or absent, and has a switching stage which is connected to a supply voltage, is switched on when a specific threshold voltage is present across the energy-storage means and in this way reduces the supply voltage. In one exemplary embodiment, when the switching stage is switched on, the charge which is dissipated from the supply voltage is at least partially routed to the energy-storage means via a diode which is connected in parallel with the said energy-storage means, so that the phase during which the switching stage is switched on is lengthened and the energy-storage means, in this case a capacitor, is completely discharged.

Abstract: A switched-mode power supply has a storage capacitor, a transformer with a primary winding and at least one secondary winding, and also a switching transistor which is connected in series with the primary winding. The primary winding is subdivided into sub-windings with at least one tap. A capacitance is disposed in parallel with each sub-winding, as a damping network. The numbers of windings of the sub-windings and the values of the capacitors disposed in parallel with the sub-windings are selected in such a way that the oscillations occurring when the switching transistor becomes blocked have different resonant frequencies and thereby partially cancel each other. This results in an effective damping of the resonant voltage over the switching transistor. Since the capacitors are connected in series, the effective total capacitance is low, so that the resulting discharge current at the time when the switching transistor becomes conductive is comparably low.

Abstract: The switched-mode power supply has a storage capacitor, a transformer with a primary winding and at least one secondary winding, and also a switching transistor which is connected in series with the primary winding. The primary winding is subdivided here into sub-windings with at least one tap, and a capacitance is in each case disposed in parallel with sub-windings, preferably with each sub-winding, as a damping network. The numbers of windings of the sub-windings and the capacitances of the capacitors disposed in parallel with the sub-windings are selected in such a way that the oscillations occurring when the switching transistor is deactivated have different resonant frequencies and thereby partially cancel each other out. This results in an effective damping of the deactivation voltage over the switching transistor.