JPH05145352A - Cathode current control circuit - Google Patents

Abstract

PURPOSE:To control a high frequency amplification factor of an electronic tube by controlling variably an anode electrode voltage to a cathode current of the electronic tube so that a cathode current of the electronic tube is kept to a set value in response to a detection temperature of a thermosensing section arranged in the electronic tube. CONSTITUTION:When a change takes place in a temperature around an anode electrode 4 during the operation of an electronic tube 1, since the size of an anode electrode and a cathode 5 is changed, a cathode current changes and a temperature change is immediately detected by a thermosensing section 13. When a temperature change causes in the electronic tube 1 and the resistance of the thermosensing section 13 is changed, the change is detected by a comparison discrimination section. The comparison discrimination section estimates a change in an anode voltage corresponding to the temperature change, it is sent to a voltage control section to control the voltage produced by a helix (body) power supply voltage generating section and an anode power supply voltage generating section. Thus, a constant cathode current is kept in following temperature change in the electronic tube 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for an electron tube, and more particularly to a cathode current control circuit for controlling the cathode current of the electron tube so as to be constant by following changes in ambient temperature.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional electronic conventional power supply device supplies a heater power supply 12 and an electronic power supply to a heater electrode 7 which is heated to emit an electron beam from a cathode 5 of an electron tube 1. A helix or body power supply 10 for generating a speed-synchronized voltage for energy coupling between the beam and the input high frequency, a collector power supply 9 for trapping the electron beam used for energy coupling and supplying energy, and an electron. A power supply device 20 including an anode power supply 11 for controlling the emission of the beam to the slow wave circuit is used to stabilize the stability so that a constant anode voltage can be supplied to the anode electrode of the electron tube 1 in order to obtain a constant cathode current. A high anode power source 19 is used.

[0003]

In this conventional power supply device for an electron tube, a constant voltage is applied to the anode electrode 4 so that a constant cathode current is obtained.
When the temperature of the body of the electron tube 1 and the anode electrode 4 change, the dimension between the electrodes changes, and as a result, the cathode current, that is, the high frequency amplification factor changes.

[0004]

The circuit of the present invention comprises a temperature-sensing portion which is arranged to be thermally connected to a predetermined position in an electron tube and detects the temperature of the temperature portion, and a cathode of the electron tube according to the detected temperature. An anode power source that variably controls the voltage applied to the anode electrode so that the current is held at a preset value.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of the constitution of an anode power supply 11 of the present embodiment. In FIG. 1, reference numeral 1 is an electron tube, and 2 is an electron tube. Collector electrode, 3 is a helix or body electrode, 4 is an anode electrode, 5 is a cathode, 5 is a cathode, 6 is a heater / cathode electrode, 7 is a heater electrode, 8 is a power supply device, 9 is a collector power supply, 10 is a helix or body power supply, 11 is Anode power source, 12 heater power source, 13 temperature sensing unit, 18
Indicates a Wehnelt electrode. The temperature-sensitive portion 13 is a temperature-sensitive resistor and is installed in the electron tube 1 and is thermally connected to the anode electrode 4 in a good condition.

When the temperature around the anode electrode 4 changes due to disturbance or the like during the operation of the electron tube 1, the cathode current changes because the dimensions of the anode electrode 4 and the cathode 5 change. The amount of temperature change is immediately detected at so that the cathode current can be kept constant.

In FIG. 2, a comparison / determination unit 14 is connected to the temperature sensing circuit 13 to make a temperature comparison / determination. The voltage control unit 15 sends an electric signal for controlling the anode voltage to the anode power supply voltage generation unit 16 and the helix or body power supply generation unit 17 according to the comparison and determination result. When a temperature change occurs in the electron tube 1 and the resistance value of the sensitive unit 13 changes, the change amount comparison / determination unit 14 detects the change. The comparison / determination unit 14 estimates the amount of change in the anode voltage corresponding to the temperature change, sends this to the voltage control unit 15, and determines the amount of voltage generated by the anode power supply voltage generation unit 16 and the helix (body) power supply voltage generation unit 17. By controlling the temperature of the electron tube 1, a constant cathode current is maintained following the temperature change.

In this embodiment, the output of the voltage controller 15 is also applied to the helix (body) power supply voltage generator 17 to control the voltage of the helix (body) electrode 3, thereby controlling the anode voltage. The change in the high frequency output characteristic of 1 can be compensated.

[0010]

As described above, according to the present invention, the temperature sensing circuit is thermally connected to each electrode of the electron tube, so that the cathode current can be generated even if the temperature of the electron tube and each electrode changes due to some cause. Can be held constant, and as a result, the high frequency amplification factor of the electron tube can be controlled to be constant.

Further, by controlling the helix or body voltage at the same time, it is possible to obtain the effect of compensating for the change in the high frequency output characteristics of electrons due to the control of the anode voltage.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram showing a specific configuration example of an embodiment of the present invention.

FIG. 3 is a block diagram of a conventional power supply circuit.

[Explanation of symbols]

 1 electron tube 2 collector electrode 3 helix or body electrode 4 anode electrode 5 cathode 6 heater / cathode electrode 7 heater electrode 8,20 power supply device 9 collector power supply 10 helix or body power supply 11, 19 anode power supply 12 heater power supply 13 temperature sensing part 14 comparison Judgment unit 15 Voltage control unit 16 Anode power supply voltage generation unit 17 Helix or body power supply voltage generation unit 18 Wehnelt electrode

Claims (3)

[Claims] 1. A temperature-sensing portion which is disposed so as to be thermally connected to a predetermined position in an electron tube and detects the temperature of the temperature portion, and a cathode current of the electron tube is held at a preset value according to the detected temperature. A cathode current control circuit comprising: an anode power supply that variably controls the voltage applied to the anode electrode. 2. The temperature sensing part is installed near the anode electrode of the electron tube and is thermally connected thereto.
The described cathode current control circuit. 3. The cathode according to claim 1, further comprising a helix or body power source that variably controls a helix or body voltage of the electron tube so as to compensate for a change in high frequency gain of the electron tube caused by voltage control of the anode power source. Current control circuit.