SU1744773A1 - Device for control over cathode-ray valve - Google Patents

Abstract

SUMMARY OF THE INVENTION: When the key 3 is unlocked, the voltage of the initial start source 5 through the diode 4 is supplied to the control electrode 2 of the valve 1. After the valve is unlocked, the control electrode current is maintained proportional to the load current 7 using a current transformer 6, which ensures an optimal control mode of the valve. Locking the key ensures that the valve is turned off. 2 Il.

Description

cl

WITH

X |

t

VJ XI

WITH

FIG. 7

This invention relates to high voltage converting and switching devices made on fully controlled electron beam valves.

A device for controlling an electron-beam valve, comprising a valve current sensor, an adjustable power source connected via a direct current switch to the control electrode of the valve and a control signal unit connected to the control input of the switch, is known.

The disadvantages of this device are the increased power losses at the valve and the increased switch-on time of the valve.

Closest to the present invention is a device for controlling an electron-beam valve, containing an adjustable power source, connected via a key to a control electrode of an electron-beam valve, a control signal unit connected to the control input of the key, a current sensor of the valve, the output of which is connected to the input of the functional unit, which converts the valve current into the output voltage in accordance with the law 3/2, the comparison unit, the first input of which is connected to the output of the functional unit, and the second input d coupled to the control electrode, the output of comparator unit connected to the control input of the adjustable voltage source, a second control input coupled to the output of the initial setting voltage, connected to the output of the block control signals.

The disadvantages of this device are low reliability and high mass-size indicators. The reliability is low due to the number of elements contained in the blocks, the presence of a powerful high-voltage source. When placing a control device at high potential, an isolation transformer of at least the same power as the regulating voltage source is required to supply it.

The purpose of the invention is to increase the reliability of the device, improving its weight and size parameters with minimal total power losses at the valve.

This goal is achieved by the fact that the control device for the electron-beam valve containing the control key, the first terminal of which is intended to be connected to the control electrode of the electron-beam valve, for connecting the 3/2

To the cathode of which the negative output of the voltage source is intended, the positive output of which is connected to the second output of the controlled key, is provided with an additional diode, a valve anode current transformer, the first output output of which is connected to the negative output of the voltage source, and the second to the second controlled output

Key 0, the voltage source, the positive output of which is connected to the second output of the controllable key through the diode, is made low-voltage, uncontrolled. Anode Current Converter

5 takes the energy needed to control the valve, and the ratio

1a / 1u K1,

where la is the anode current of the valve; 0ly is the control electrode current of the valve;

K1 is the transformation ratio of the current converter.

This ratio holds when

five . Equation of degree 3/2 for triode

has the appearance

 (IVDUa) where K2 is the proportionality coefficient, taking into account the lamp perveance and its design features;

U is the voltage across the control electrode;

D is grid permeability; 4- Ua is the voltage at the anode of the lamp. 5 For electron-beam valves operating in switch mode, the anodic characteristics, as a rule, have a foam appearance and, when operating in the key mode, the second term in brackets in the equation of degree 3/2 for a triode is small .

Considering the following transformations: 1a K11u; lk ly + la; 5Ik ly + K1 - (k1 + 1) 1uKZ

with good accuracy is acceptable ratio

1uKZ K211u3 / 2,

i.e., the electron-beam valve, switched on- according to the proposed scheme, is controlled in the near-optimal mode.

FIG. 1 shows a control device for an electron-beam valve; FIG. 2 is a diagram of a possible implementation of an anode current transformer 5.

The device (Fig. 1) contains an electron-beam valve 1. The control electrode 2 of the valve 1 is connected via a control switch 3 and a diode 4 to the voltage source 5, as well as to the anode current transformer 6

valve 1, the second output is connected to the common connection point of the diode 4 and the control key 3.

The anode current transformer 6 of the valve (Fig. 2) contains transistors 8, 9 connected in series with each half-winding of the transformer 10, a high-voltage rectifying bridge 11 at the output of the secondary winding of the transformer 10, and a varistor 12 for protecting transistors 8, 9 from overvoltages.

The device works as follows.

When a control signal of transistors 8, 9 with a frequency of tens of kilohertz and a constant signal to the control key 3 (the transistors 8, 9 switch in antiphase) from the voltage source 5 is applied simultaneously to diode 4 and the control key 3, the voltage is applied to control electrode 2 valve 1, which leads to its opening. Through the valve 1 and the transformer of the anode current of the valve, a current begins to flow, the magnitude of which is determined by the parameters of the load 7 of the valve 1. At the output of the rectifying bridge 11 there is a voltage that is applied through the control switch 3 to the control electrode 2 of the valve one.

Thus, any change in the anode current of the valve will lead to a change in voltage at its control electrode in close accordance with the law of degree 3/2.

The transformation ratio of the transformer 10 is selected based on the type of valve, in which, at a given anode current, the minimum value of the control electrode current of the valve is determined, which determines whether the valve is in the key mode.

The valve 1 is turned off by simultaneously removing control signals from the control key 3 and

transistors 8, 9 converter b current. Switching off the transistors 8, 9 is faster than turning off the valve 1 (due to the parasitic capacitance of the control electrode

- cathode), which leads to overvoltage on the transistors. A varistor 12 is introduced to protect the transistors from overvoltages.

The proposed device provides an electron beam control mode.

the valve is close to optimal in a wide range of the anode current of the valve and in comparison with the prototype has increased reliability due to fewer elements and better

weight and size indicators.

When installing a control unit at high potential, it is necessary to use an isolation transformer of n units of watts for its power supply from the ground potential, in contrast to the prototype, for the power supply of which an isolation transformer of hundreds of watts is necessary.

Claims (1)

Claims An apparatus for controlling an electron beam valve comprising a control key, the first terminal of which is intended to be connected to a control electrode of an electron beam valve, for connection to which cathode A negative output of a voltage source is intended, the positive output of which is associated with a second output of a controllable key, characterized in that, in order to increase reliability and reduce the masses and dimensions, the diode and the transformer of the anode current of the valve are introduced, the first output terminal of which is connected to the negative terminal of the voltage source, and the second to the second terminal of the control key, the voltage source, the positive terminal of which is connected to the second output of the controlled key through the diode, made uncontrollable.