Thomson-Brandt

Gerard Rilly

Erich Geiger

Joseph Colineau

Michel Facon

Appukuddy Sivanesan

The current which passes through the vertical deflector of a transistorized color television receiver is produced by a circuit comprising an active switch controlled and modulated at the line frequency and supplied by line retrace pulses delivered by the secondary winding of a line transformer. The voltage at the terminals of an assembly compring a capacitor in series with the vertical deflector has a constant sign which is independent of the current passing through the deflector. The same secondary winding of the line transformer supplies both the vertical scanning circuit and a rectifier circuit for producing a d.c. voltage, in particular for the supply of video amplifiers.

Generator for producing a d.c. supply voltage in a television receiver

Step-up switching regulator power supply device comprising, connected between the poles of a rectifier circuit supplied by an isolating voltage step-down transformer and loaded by a first filter capacitor, and inductance and the collector-emitter path of a first switching transistor of NPN type, a first diode whose anode is connected to the junction of the inductance and to the collector of said transistor and whose cathode is connected to a second filter and storage capacitor supplying a voltage at its output which supplies a horizontal deflection circuit of a television receiver. This horizontal deflection circuit which comprises in cascade a horizontal oscillator, a driver stage and an output stage, forms an integral part of the circuit controlling said first transistor and determines the repetition period of the switching, because it is started under an initial voltage slightly less than the unregulated input voltage of the device. The switching transistor is being turned off in synchronism with the turning off of the trace switch transistor by using flyback pulses of negative polarity to bias the base thereof.

Switching regulator power supply device combined with the horizontal

Wave-chopping is performed by means of an active switch, said switch being unidirectional in voltage and bidirectional in current and connected in series with a secondary winding of the horizontal-scanning transformer. The secondary winding is connected in series with an inductance coil which is not coupled to the transformer and with a polarized capacitor, the output voltage being collected at the terminals of the capacitor. The power supply circuit is employed in video-frequency receivers having low dissipation.

Circuit for stabilized power supply in conjunction with the horizontal

The switched-mode field-scanning circuit makes use of a load constituted by a vertical deflector, a measuring resistor and a connecting capacitor. The load is connected to the output of a circuit which generates a sawtooth signal by means of the line-scanning retrace signal and has a single unidirectional-voltage, bi-directional-current channel. The switched-mode field-scanning circuit is intended for use in transistorized video-frequency receivers.

Switched-mode field-scanning circuit of video-frequency receiver

This circuit comprises a saw-tooth signal generating circuit having a single active switch monodirectional in voltage and bidirectional in current, controlled by a cyclic ratio control circuit connected, on the one hand, to a static servo-control circuit so as to ensure optimum operation of the active-switch circuit and, on the other hand, to a dynamic servo-control circuit so as to ensure conformity of the law of variation of the current in the deflector with respect to an S-corrected frame saw-tooth law. Such a circuit is used in transistorized videofrequency receivers.

Switched-mode frame-scan control circuit for a videofrequency receiver

A regulated power supply device, in particular for a line sweep circuit in a television receiver, containing a chopper circuit (10) which contains in series an inductor (16) and a bidirectional switch (15), which is controlled and mounted in parallel with a capacitor (13), forming a resonant circuit with the inductor (16) when the chopper switch (15) opens. The inductor (16) contains a winding (21), called the power supply winding, of a transformer (20), called the line transformer, in which another winding (22), mounted in series with a reservoir capacitor (33), is connected in parallel with another bidirectional switch (35 and 36), which equips the line sweep output stage (30). The transfer of energy between the chopper circuit (10) and the output stage (30) is done through the windings (21 and 22) of the transformer (20) and its effect is to charge the reservoir capacitor (33) which feeds, apart from the output stage (30), the preceding stages of the sweep circuit (which are not shown). The regulation is done by means of a regulation circuit (40) which receives the line return pulses from an additional winding (25) on the transformer by causing the phase shift to vary between the cut off (opening) instants of the two switches (10 and 35, 36).

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Paris, France

Gerard Rilly