DE1028170B - High voltage generation from the line return - Google Patents

Description

GERMAN

With higher demands on the high voltage for the operation of television picture tubes, it is difficult to generate high voltages of 20 kV and more without too much effort. The transformation of the High-voltage winding is limited by the self-capacitance of the coil winding. The usual Voltage multiplier circuits always require several capacitors, the final voltage between the occupancy and according to mass or zero can safely tolerate. Since in many cases the normal undoubted high voltage has a function to perform in addition to doubled voltage sometimes a smooth doubling or multiplication is undesirable, since this tension then increases would be high. For these purposes it is better to use the rectified high voltage a desired one to add additional voltage as it were, which is most advantageous from the line pulse amplifier Rectification of the line pulses is obtained.

A circuit arrangement is already known in which two rectifier sections are connected in cascade and doubling the voltage by means of three capacitors and a charging resistor is attainable. A new cascade stage is required for further increases in voltage. The required effort quickly increases, and the switching elements must be able to withstand high loads.

In another known circuit arrangement, with the rectification of the return peaks The high DC voltage generated is connected in series with an additional DC voltage, which is generated with the help of a second high-voltage winding and another rectifier will.

In such known devices, however, it is disadvantageous on the one hand that the rectifier and the charging capacitor for the additional rectification must withstand the increased final voltage to earth or zero or, on the other hand, the capacitance of the latter is in series with that of the charging capacitor of the normal high voltage obtained from the flyback , whereby the total loading capacity is unnecessarily reduced and special expenditures are necessary in order to still achieve a satisfactory end result. These disadvantages and the hitherto required great effort is avoided in a circuit arrangement for high voltage generation for television sets in which unidirectional return pulses are used and a cascade circuit with two rectifier sections, three capacitors and a charging resistor to increase the voltage is used Storage capacitor, which is located between the two rectifier sections and before the second high-voltage generation
from the return line

Applicant:

Max Grundig,
Fürth (Bay.), Kurgartenstr. 37

Bruno Fischer, Landshut (Bay.),
has been named as the inventor

A winding that transforms the basic alternating voltage upwards is provided, which is coupled to the feed winding for the first rectifier path.

Since in the circuit arrangement according to the invention only the voltage values of the additional voltage generation need to be taken into account and these generally only about a third to one Quarter of the final voltage can be used as an advantageous further development of the invention instead of The rectifier also has a control tube to stabilize the basic voltage and thus also the final voltage be used.

The invention will be explained in more detail using a circuit example according to the drawing. The ones from Amplifier tube 1 supplied to the deflection coil 2 for the horizontal deflection pulses of a television receiver Pulse voltage is rectified by a rectifier 4 and is available on the capacitor 5, while the flyback pulse voltage across a capacitor 3 of the autotransformer coil 6 is forwarded. The thus standing at the capacitor 5 and designed as a voltage divider resistor chain 7, 8, 9 conducted additional DC voltage accordingly sets the pulsating AC voltage in the coil 6 by the amount of DC voltage obtained from the pulse voltage higher by is fed to the base of the coil 6. The coil 6 can therefore be unchanged up to the limit of their Data are exploited and their voltage is output to the rectifier diode 10.

A unidirectional pulse voltage is induced in the coil 2 at the connection point between the coil 2, the rectifier 4 and the capacitor 3. During the assumed first pulse, the capacitor 5 is charged to the voltage U _{1, for example, in accordance with the peak value.} That

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the same potential is fed to the capacitor 3 via the resistor 8. After termination of the voltage pulse, the voltage at the connection point between coil 2 and capacitor 3 drops to zero. The connection point between the capacitor 3 and the coil 6 receives the potential of the capacitor 5 via the resistor 8. If the i? C element is correctly dimensioned, whereby a diode would also be conceivable instead of the resistor, the capacitor 3 acts as a voltage source with a stored voltage DC voltage. With the pulse that now follows, a voltage is again induced at the connection point of the coil 2 with the capacitor 3 and the diode 4. Both voltages - the DC voltage stored in the capacitor corresponding to U ₁ and the pulse peak arising in the winding = U ₁ - are connected in series and add up. The voltage from the coil 6 is added to this total voltage. The final voltage is therefore U ₁ Imp. + JJ ₁ equal to +? 7 ₀ Imp., Which corresponds to the value = U ₁ + (U ₁ + U ₂ ).

Nevertheless, with this arrangement at the cathode 12 of the diode 10, a pulse voltage that is rectified by the amount of the rectified higher pulse voltage arises, the turns of the coil 6 do not need one another higher insulation, which is important for the construction of such arrangements.

The additional basic DC voltage can be regulated by the potentiometer 7 by small amounts It goes without saying that only one fixed resistor 8 could be provided instead of the voltage divider be. The charging capacitor 11 of the high-voltage rectifier, which is dimensioned for the final voltage 10 remains unchanged in its value, while the capacitor 5 is designed only for the voltage which comes from the pulse voltage and about a third to a quarter of the real high voltage.

An advantageous development of the invention is given in that the rectifier 4 in itself known way can be replaced by a controllable tube and thus a stabilization of the Total high voltage is possible. The control voltage for this tube can be derived from the final voltage or derived from the additional DC voltage. Since the voltages occurring at the rectifier 4 can generally still be mastered with the usual controllable tubes, according to a Further development of the invention enables a simple high-voltage stabilization that would otherwise only be possible with greater effort is to be realized.

Claims (4)

Patent claims: 1. Circuit arrangement for high voltage generation for television sets, in the unidirectional Return pulses are used and a cascade connection with two rectifier sections, three capacitors and a charging resistor is used to increase the voltage, characterized in that after the Storage capacitor (3), which lies between the two rectifier sections, and in front of the second Rectifier section (10) a winding (6) that transforms the basic alternating voltage is provided, which is coupled to the feed winding (2) for the first rectifier path (5). 2. Circuit arrangement according to claim 1, characterized in that a voltage divider for the purpose of changing the basic DC voltage taken from the output circuit of the first rectifier path is provided. 3. Circuit arrangement according to claim 1, characterized in that the first rectifier path a controllable tube is provided for the pulse voltage obtained from the line return which is used to stabilize the high voltage. Considered publications:
German Patent No. 725 043;
Funk und Ton, 1953, no. 4, p. 188. 1 sheet of drawings © 709 960/263 4.5 «