JPH06310045A - Heater power source of traveling wave tube - Google Patents

Abstract

PURPOSE:To switch from the condition after inputting a heater power source to a transmission mode in a short period of time by making the voltage of the heater electrode of a traveling wave tube variable. CONSTITUTION:The energy from the stabilizing power source in the output voltage which is vi, is input into the center tap of a transformer 13. The gate signal of a FET 14 is output from a control circuit 17 directly after a heater power source is input. The voltage of (n4/n2) Vi is generated between I and J points of the transformer 13 at the time, and a diode 6 is electrified. When the FET 14 is turned OFF, the excitation energy of a coil n2 is transferred to a coil n3, while a diode 16 is electrified, and the transfermer 13 is reset. After a heater is sufficiently warm, the gate signal of a FET 15 is output from the circuit 17, and the gate signal of the FET 14 is turned OFF thereafter. The voltage of (n4/n1+n2) Vi is generated between the points I and K of the transformer 13. The rectifier diode is electrified at the time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention aims to shorten the warm-up time by changing the voltage of the heater electrode of a traveling wave tube and to switch from the state after the heater power is turned on to the transmission mode in a short time. The present invention relates to a configuration of a traveling-wave tube heater power source intended.

[0002]

2. Description of the Related Art FIG. 8 is a diagram showing an example of the configuration of a conventional traveling-wave tube heater power supply. In the figure, 1 is a stabilized power supply, 2 is a transformer, 3 is a gate driver circuit for outputting a gate signal, and 4 is a field effect transistor (hereinafter referred to as FET).
5 is an FET, 6 is a rectifying diode, 7 is a rectifying diode, 8 is a choke coil, 9 is a capacitor, 1
Reference numeral 0 is a Zener diode for absorbing surge, 11 is a cathode electrode, and 12 is a heater electrode.

Next, the operation will be described. Energy from the stabilized power supply is input to the center tap of the primary side of the transformer 2, and a current flows to the ground through the FET 4 and FET 5 that are on / off controlled so as to perform push-pull operation in the gate driver circuit 3. The voltages at points A and B in FIG. 8 at this time have the waveforms shown in FIGS. 9A and 9B. Energy is accumulated in the transformer 2 when a current flows through the transformer 2, the FET 4 or the FET 5, and a voltage obtained by multiplying the primary side winding and the secondary side winding ratio n2 / n1 by the primary side voltage is output to the secondary side. To be done. For example, when the FET 4 is on, the stabilized power supply Vi is generated between the points C and A, and at this time, the voltage of Vi · (n2 / n1) is output between the points E and F, and the rectifying diode 6 Conducts. Similarly, when the FET 5 is on, a voltage of Vi · (n2 / n1) is output between the D point and the F point, and the rectifying diode 7 becomes conductive. Therefore, G
The voltage at the point has the waveform shown in FIG. This voltage waveform has a high-frequency component removed by a filter formed by the choke coil 8 and the capacitor 9, and the heater electrode is shown in FIG.
The DC voltage shown in (d) is output.

[0004]

The conventional traveling-wave tube heater power supply is constructed as described above, and when a certain constant voltage is applied, the heater filament existing near the cathode electrode is heated. Makes it easier for electrons to be emitted. However, in the conventional method, it often takes a while for the heater power to be turned on and the filament to be sufficiently warmed up, which is often a fatal defect in defense equipment and communication equipment.

The present invention has been made in order to solve the above problems, and an object thereof is to shorten the warm-up time by making the heater power supply output voltage variable.

[0006]

The traveling-wave tube heater power supply according to the present invention outputs a DC voltage higher than the normal heater power supply output voltage immediately after the heater power is turned on, and after the filament is sufficiently warmed, the normal DC power is supplied. It is equipped with a function to control to return to voltage.

Some traveling-wave tube heater power supplies can be used with an AC voltage. Immediately after the heater power is turned on, an AC voltage higher than the normal heater power output is output, and after the filament has warmed sufficiently, the normal AC voltage is applied. It is equipped with a function to control to return to.

[0008]

In the traveling-wave tube heater power supply according to the present invention, the temperature of the heater filament can be rapidly raised by outputting a voltage higher than the normal voltage immediately after the power is turned on, so that the warm-up time is shortened. Therefore, it is possible to transmit immediately after the heater power is turned on. The relationship between the heater voltage and the filament temperature is shown in FIG. The curve (a) in FIG. 10 shows the relationship according to the conventional method, and the curve (b) shows the relationship according to the present invention.

Further, the traveling-wave tube heater power supply according to the present invention does not need to form two transformers for supplying a normal voltage and a voltage higher than the normal voltage, and one transformer outputs two kinds of voltages. This leads to downsizing and cost reduction of the traveling wave tube heater power supply.

[0010]

【Example】

Embodiment 1 FIG. 1 is a block diagram showing the configuration of a traveling wave tube heater power supply according to one embodiment of the present invention. In the figure, 1, 6-12
Is the same as the above conventional device. Reference numeral 13 is a transformer having three windings on the primary side and one winding on the secondary side, 14 is a FET, 15 is a FET, 16 is a diode for preventing reverse current, and 17 is a gate driver control circuit.

Next, the operation will be described. Output voltage is V
Energy from the stabilized power source of i is input to the center tap of the transformer 13. Immediately after the heater power is turned on, the gate driver control circuit outputs the gate signal of the FET 14. Therefore, the current input from the center tap flows through the winding n2 and the FET 14 to the ground. At this time, if the number of turns between the I point and the J point on the secondary side of the transformer 13 is n4, a voltage of (n4 / n2) · Vi is generated between the I point and the J point. At this time, the rectifying diode 6 becomes conductive. Therefore, when the gate signal of the FET 14 is turned off from the gate driver control circuit 17, it is necessary to reset the transformer 13, and the diode 16 and the winding n3 are provided for this purpose. When the FET 14 is turned off, the excitation energy stored in the winding n2 moves to the winding n3, and the exciting current of the winding n3 is expressed by the following equation.

[0012]

[Equation 1]

At the same time, the diode 16 becomes conductive and regenerates the excitation energy to the input power source through the ground, the diode 16 and the winding n3, and the transformer 13 is reset. At this time, to prevent the saturation of the transformer 13,
The ratio at which 14 is on is limited by the following equation.

[0014]

[Equation 2]

Since no voltage is output to the secondary side of the transformer 13 while the FET 14 is off, the relationship between the voltage at the point K in FIG. 1 and the gate drive signal of the FET 14 is shown in FIG.
As shown in (a) and (b). The voltage output to the K point is smoothed by the filter including the choke coil 8 and the capacitor 9, and the heater electrode 12 and the cathode electrode 1
The waveform becomes as shown in FIG. Next, after the heater is sufficiently heated, the gate driver control circuit 17
Outputs the gate drive signal of FET15 from
The gate drive signal of ET14 is turned off thereafter. That is, the current from the regulated power supply is applied to the windings n2 and n3, and F
It flows through ET15 to the ground. At this time, transformer 1
Between the points I and K on the secondary side of 3 is (n4 / n1 + n2)
・ Vi voltage is generated. At this time, the rectifying diode 6 becomes conductive. FET15 to prevent saturation of the transformer 13
The ratio of ON is limited by the following equation.

[0016]

[Equation 3]

After that, the same operation as described above is performed. Figure 5
These relationships are shown in (a), (b) and (c). For example, when the windings n1 and n2 are equal, a voltage of (n4 / n1) · Vi is obtained on the output side while the FET 14 is on, and (n4 / n1 · 2) while the FET 15 is on. )
Since the voltage of Vi can be obtained, when the FET 14 is on, approximately four times the power can be supplied to the heater, and the warm-up of the heater can be accelerated.

Embodiment 2 FIG. 2 is a block diagram showing the configuration of a traveling-wave tube heater power supply of another embodiment of the present invention. In this embodiment, the heater power source is AC, and in the figure, 1, 3 to 5, 1
1 and 12 are the same as the conventional device. Reference numeral 18 is a transformer, 19 is a choke coil, and 20 is a control circuit.

Next, the operation will be described. Energy from the stabilized power supply 1 is input to the center tap of the transformer 18. Gate driver circuit 3 consists of FET4 and FE
The gate drive circuit is output so that T5 is alternately turned on, and the transformer 18 is made to push-pull. When the stabilized power supply output voltage is Vi, the number of turns between the center tap of the transformer 18 and both ends is n1, the secondary winding is n2, and the frequency of the gate drive signal is fs, the voltage on the secondary side of the transformer 18 is + (N2 / n1) · Vi and − (n2 / n1)
-It becomes a pulse signal of frequency fs which oscillates between Vi.
This relationship is shown in FIG. Immediately after the heater power supply, the control circuit 20
Then, a DC voltage sufficient to saturate the choke coil 19 is output, the choke coil 19 is in the air-core state, and the inductance component disappears. Therefore transformer 1
The AC voltage appearing on the secondary side of 8 is directly output between the heater electrode and the cathode electrode. Next, after the heater is sufficiently warmed, the heater power supply is controlled to output a normal voltage. The DC voltage output from the control circuit 20 is turned off, and the inductance component L of the choke coil 19 appears. The impedance of the choke coil 19 at this time is expressed by the following equation.

[0020]

[Equation 4]

Therefore, when the load of the heater is Rh, the amplitude of the voltage output to the heater electrode is expressed by the following equation.

[0022]

[Equation 5]

The relationship between the output of the control circuit 20 and the heater voltage is shown in FIG. For example, in Equation 5, when the inductance or frequency is adjusted so that the impedance of the choke coil 19 and the heater load are equal, the voltage immediately after the heater power is turned on is twice the normal voltage, and the heater is supplied with four times the power. It can be supplied, and the warm-up of the heater can be accelerated.

Embodiment 3 FIG. 3 is a block diagram showing the structure of a traveling-wave tube heater power supply according to another embodiment of the present invention. In this embodiment, the heater power source is AC, and in the figure, 1, 3 to 5, 1
1 and 12 are the same as the conventional device. Reference numeral 18 is a transformer, 19 is a choke coil, 20 is a control circuit, and 21 is a temperature detection circuit.

Next, the operation will be described. The operation is similar to that of the second embodiment, but is characterized in that the temperature detection circuit 21 is installed near the heater electrode. Immediately after turning on the power to the heater, a DC voltage is applied from the control circuit 20 so as to saturate the choke coil 19 and eliminate the inductance component immediately after the heater power is turned on, and the temperature of the heater that is rapidly heated is detected as in the second embodiment. The inductance of the choke coil 19 is controlled by controlling the DC voltage from the control circuit according to the temperature detected by the circuit 21. When the temperature reaches the transmittable temperature, the DC voltage from the control circuit 20 is turned off, the inductance component of the choke coil 19 appears, and the heater power supply returns to the normal voltage. By installing the temperature detection circuit 21, it is possible to automatically perform control to return to the normal voltage when the heater temperature reaches the transmittable temperature regardless of the switching frequency and the inductance L, and to prevent overheating of the heater. You can

[0026]

According to the third embodiment of the present invention, since the voltage of the heater power source is controlled while the temperature is detected by the heater temperature detection circuit, when the heater temperature exceeds the transmittable temperature. It is possible to control so as to immediately drop the voltage, to prevent wasteful power consumption, to prevent overheating, and to prevent the heater filament or the like from being broken.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a traveling-wave tube heater power supply according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a traveling wave tube heater power supply according to another embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a traveling wave tube heater power supply according to another embodiment of the present invention.

FIG. 4 is an F diagram of a traveling wave tube heater power supply according to the first embodiment of the present invention.
It is a figure which shows the gate signal of ET14, the secondary side voltage of the transformer 13, and the relationship of a heater voltage.

FIG. 5: F of traveling-wave tube heater power supply according to Embodiment 1 of the present invention
It is a figure which shows the gate signal of FT15, the secondary side voltage of the transformer 13, and the relationship of a heater voltage.

FIG. 6 is a diagram showing the relationship between the gate signals of the FET 4 and FET 5 and the secondary side voltage of the transformer 18 according to the second embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between a control signal of the choke coil 19 and a heater voltage according to the second embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a conventional traveling-wave tube heater power supply.

FIG. 9 is a diagram showing the relationship among the drain voltage of FET4, the drain voltage of FET5, the secondary side voltage of the transformer 2, and the heater voltage of the conventional traveling-wave tube heater power supply.

FIG. 10 is a diagram showing a relationship between a heater voltage and a heater filament temperature.

[Explanation of symbols]

 1 Stabilized Power Supply 2 Transformer 3 Gate Driver Circuit 4 FET 5 FET 6 Rectifying Diode 7 Rectifying Diode 8 Choke Coil 9 Capacitor 10 Zener Diode 11 Cathode Electrode 12 Heater Electrode 13 Transformer 14 FET 15 FET 16 Diode 17 Gate Driver Control Circuit 18 Transformer 19 Choke coil 20 Control circuit 21 Temperature detection circuit

Claims (3)

[Claims] 1. A transformer consisting of three windings on the primary side and one winding on the secondary side, a stabilized power supply connected to a center tap of the primary side of the transformer, and a transformer for the transformer. A field effect transistor connected to the secondary side inter-tap, a field effect transistor connected to the primary side edge tap of the transformer, a reverse current prevention diode connected to the other edge tap of the transformer, and the above two A gate driver control circuit for outputting a gate signal of a field effect transistor, two rectifier diodes connected to the secondary side of the transformer, a choke coil connected to the rectifier diode, and a capacitor connected to the choke coil, Zener diode for surge absorption, cathode electrode connected to one end of the above capacitor, and the other end of this capacitor A traveling-wave tube heater power supply having a heater electrode connected to the. 2. A transformer composed of two windings on the primary side and one winding on the secondary side, a stabilized power supply connected to a center tap of the primary side of the transformer, and a transformer for the transformer. A field effect transistor connected to the next side edge tap, a field effect transistor connected to another edge tap of the transformer, a gate driver circuit for outputting gate signals of the two field effect transistors, and a secondary of the transformer. A traveling-wave tube heater power supply having a choke coil connected to the side, a control circuit connected to the choke coil, a heater electrode connected to the choke coil, and a cathode electrode. 3. A transformer comprising two windings on the primary side and one winding on the secondary side, a stabilized power supply connected to a center tap of the primary side of the transformer, and a transformer for the transformer. A field effect transistor connected to the next side edge tap, a field effect transistor connected to another edge tap of the transformer, a gate driver circuit for outputting gate signals of the two field effect transistors, and a secondary of the transformer. A choke coil connected to the side, a heater electrode connected to the choke coil, a cathode electrode, a temperature detection circuit for detecting the temperature of the heater filament, and a control circuit connected to the temperature detection circuit and the choke coil. Power source for traveling wave tube heater.