DE1058109B - Circuit for keeping a high DC voltage constant on a load circuit - Google Patents

Description

The invention relates to a circuit arrangement for feeding a load circuit a high DC voltage, which with the help of a rectifier circuit in the anode circuit of a AC voltage occurring in the first tube is taken. To the high DC voltage with variable To keep the load almost constant, the rectifier circuit is also by a second tube loaded, the control grid of which is taken from a resistor, from the total load current dependent control DC voltage is supplied.

Circuit arrangements of this type are z. B. to generate the high DC voltage of a cathode ray tube by rectifying the AC voltage of a sinusoidal oscillator or, as this is more general Common is by rectifying the voltage pulses used during the kickback of the horizontal deflection current via the deflection coils or inductances coupled with them or transformers occur. It is known to do the second, causing additional stress To connect the tube parallel to the cathode ray tube. The regulating DC voltage to control the second Tube is removed from a resistor, which is in the common cathode circuit of the second Tube and cathode ray tube. This circuit arrangement has the disadvantage that the resistance is contained in the cathode circuit of the cathode ray tube, so that the potential of the cathode of the The cathode ray tube is not constant and depends on the beam current strength present in the cathode ray tube depends.

The circuit arrangement according to the invention aims to eliminate this disadvantage, and has Feature that the resistor is on the AC voltage side of the rectifier circuit. The one The end of the resistor is with an inductance and located in the anode circuit of the first tube the other end to the rectifier circuit and via an integrating network to the control grid connected to the second tube, which is connected in parallel with the load circuit.

The circuit arrangement according to the invention is explained in more detail using an exemplary embodiment shown in the drawing. 4-5

A first winding 2 of a transformer 3 is inserted into the anode circuit of the tube 1 of the alternator. This transformer is also provided with a second winding 4 , one end of which is connected to the anode of a rectifier 5 . The other end of the winding 4 is connected to the end 6 of a resistor 7 , the end 8 of which is connected to the anode of the tube 1. A capacitor 9 is located in parallel with the resistor 7.

Circuit for keeping constant
a high DC voltage
on a load circle

Applicant:
NV Philips' Gloeilampenfabrieken,
Eindhoven (Netherlands)

Representative: Dipl.-Ing. K. Lengner, patent attorney,
Hamburg 1, Mönckebergstr. 7th

Claimed priority:
Netherlands 28 July 1955

Leendert Johan van de Polder
and Josue Jean Philippe Valeton,

Eindhoven (Netherlands),
have been named as inventors

The cathode of the diode 5 is connected to the anode of a cathode ray tube 10 , the cathode of which is connected to earth. A smoothing capacitor 11 is located parallel to this cathode ray tube 10. In addition, a second tube 12 is connected in parallel to the cathode ray tube as an additional controllable load. The end 6 of the resistor 7 is connected through the resistor 13 to the control grid of the loading tube 12 , and the capacitor 14 is provided between the control grid and the cathode of this tube.

The tube 1 of the alternator is controlled in such a way that an alternating voltage occurs across the winding 2. For this purpose a voltage which periodically blocks the tube can be fed to the control grid, as is the case when the tube 1 forms the end tube of a deflection circuit. The tube 1 can also be fed back in such a way that a sinusoidal alternating voltage occurs across the winding 2 . All of these operating methods for the tube 1 are known per se and are immaterial for a good understanding of the present invention.

As a result of the occurrence of an alternating voltage across the winding 2 , an alternating voltage also occurs across the winding 4 , so that a high direct voltage arises across the capacitor 11, which the electron-

909-52Ä / 277

Claims (1)

jet tube 10 and the second tube 12 is fed. If ^ ₁₀ to the cathode ray tube 10 by flowing current and i ₁₂ to the tube denote 12 by flowing current, so the total load current i _g is the rectifying circuit Y ₁₀ + ^ · Due to this load current i _g occurs a charge reduction on capacitor 11 a. This reduction must be compensated periodically when the diode 5 becomes conductive, so that the mean current through the diode 5, the winding 4 and the resistor 7 should also be i _i0 + i ₁₂ . The mean potential at point 8 is equal to the DC anode voltage V of tube 1. If R denotes the value of resistor 7, then the mean potential at point 6 is V - R (i ₁₀ +% ₂ ) ^: This mean potential becomes point 6 taken by means of the integrating network consisting of the resistor 13 and the capacitor 14 , so that the potential of the control grid of the tube 12 is equal to V-R (i ₁₀ + i ₁₂ ) . If the current i ₁₀ through the cathode ray tube 10 increases under the effect of an image signal which is fed to a control grid (not shown), the potential at the control grid of the tube 12 decreases, so that i ₁₂ decreases, whereby the change in the total load current i _g = i ₁₀ + i ₁₂ ^a 5 counteracts, but the total load current ig cannot be kept exactly constant. The stabilization of this current i _g is improved to the extent that the steepness of the second tube 12 and the voltage V are selected to be greater. In parallel with the resistor 7 is the capacitor 9, which is a short circuit for the higher frequencies forms, which have almost no influence on voltage changes across the capacitor 11 , since the time constant of the capacitor 11 and the tubes connected in parallel to this and acting as a load resistor is sufficiently large to smooth out brief changes in the load current. Claim: Circuit for keeping a high DC voltage constant to a load circuit, which is obtained by means of a rectifier circuit from an AC voltage, which in turn is taken from the anode circuit of a first tube, and in which the rectifier circuit is also loaded by a second tube, the control grid of which is connected to a resistor Taken off, dependent on the total load current control DC voltage is supplied, characterized in that the resistor (7) is on the AC voltage side of the rectifier circuit and that one end with an inductance lying in the anode circuit of the first tube and the other end of the resistor with the rectifier circuit and via a integrating network is connected to the control grid of the second tube, which is connected in parallel to the load circuit. Considered publications:
German Patent Nos. 895 010, 904 420;
Swiss Patent No. 219 028;
British Patent No. 716 602. 1 sheet of drawings © 909 528/277 5.59