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:
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:
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 control circuit for controlling a brushless motor for a washing machine comprises AC main voltage, a phase-trimming circuit for trimming the AC main voltage and supplying the trimmed AC main voltage to the stator windings of the brushless motor, depending on a control voltage derived from a rotor position sensor of the brushless motor. The phase-trimming circuit changes the polarity of the trimmed AC main voltage so that a first polarity is supplied to a first stator winding and a second polarity is supplied to a second stator winding of the brushless motor.
Abstract:
A direct-voltage converter for supplying an appliance with an inductive component, in which two transistors are connected in series between direct-current voltage terminals and are made alternatively conductive in a push-pull mode by the first of two windings of a transformer. Two free-running diodes are connected in parallel to the transistors, and a junction between the two diodes supplies their output voltage. This junction is connected to a further junction between the transistors, through a third winding on the transformer. An electronic switch is connected in parallel with a fourth winding of the transformer, and is periodically made conductive by the output voltage through a pulse shaper with a switching pulse. The pulse shaper has two direct current circuit points which determine the peak value and relationship of currents flowing through the two transistors. An amplitude-comparison stage in the pulse shaper has inputs connected to the two circuit points. The output voltage of the amplitude-comparison stage controls the frequency of the switching pulse. The arrangement is such that the converter protects against overload.