JPH0143481B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-speed discharge protection device used to protect a high-power multipole amplifier tube in a radar device or the like.

Conventional power supply systems for multipole amplifier tubes include a single power supply system and a dual power supply system, as shown in FIGS. 1a to 1c. In the figure,
1 is a multipole amplifier tube, 2 is a grid modulator, 3 and 7 are resistors, and 4, 5, 6, 8 and 9 are power supply systems. When comparing Figure 1a, which is a single power supply system, and Figures 1b and c, which are dual power supply systems, the dual power supply system generally improves the efficiency of the multipole amplifier tube. Used a lot.

Detection of moving targets in radar equipment (hereinafter referred to as
One of the main factors to increase the ability (denoted as MTI) of the high frequency output signal of the transmitting amplifier tube is the hit
It is necessary to reduce the phase fluctuation between -to-hit.
Amplifying tubes such as TWT use input/output due to fluctuations in cathode voltage (voltage applied between the cathode and body of the amplifier tube) or collector voltage (voltage applied between the collector and body of the amplifier tube). Phase fluctuation occurs in the high-frequency signal between the two. The ratio △φ/E of the voltage E applied to the amplifier tube and the phase variation △φ is called phase sensitivity. Generally, the phase sensitivity to cathode voltage variation is several tens of times larger than the phase sensitivity to collector voltage variation, so the cathode voltage Reducing the fluctuation in the phase fluctuation of the high-frequency signal leads to the improvement of MTI performance.

In Fig. 1c, when the amplifier tube operates, the power supply 8 causes a voltage fluctuation proportional to the body current, and the power supply 9
causes a voltage fluctuation proportional to the collector current. Generally, in a grid modulation type TWT, the body current is smaller than the collector current, so the voltage fluctuation of the power source 9 is relatively large, but the voltage fluctuation of the power source 8 can be suppressed to a small value.

In other words, the power supply system shown in FIG. 1c can be said to be a power supply system in which fluctuations in the collector voltage of the amplifier tube are relatively large, but fluctuations in the cathode voltage can be kept small. That is, since the phase sensitivity to the collector voltage is small and the phase sensitivity to the cathode voltage is large, this is a power supply system that can suppress hit-to-hit phase fluctuations of the high frequency output signal to a small level overall.

On the other hand, in FIG. 1b, the voltage of the power source 5 varies in proportion to the body current, and the voltage of the power source 6 varies in proportion to the sum of the body current and the collector current. The voltage fluctuation of the power supply 5 becomes the collector voltage fluctuation, and the sum of the voltage fluctuation of the power supply 5 and the voltage fluctuation of the power supply 6 becomes the voltage fluctuation of the cathode voltage. Therefore, the fluctuation of the cathode voltage is relatively large and the collector voltage The fluctuation is small. In other words, the hit-to-hit phase fluctuation of the high-frequency output signal cannot be kept small overall.

From the above, comparing the power supply systems shown in Figure 1 a, b, and c, it can be said that the power supply system shown in Figure 1 c is the system that can improve the MTI performance of radar equipment and efficiently use the multipole amplifier tube. .

In general, multipole amplifier tubes may be damaged if arcing occurs within the tube and energy of several tens of joules or more is injected into the tube. Therefore, a high-speed discharge protection device is required that minimizes the energy consumed within the amplifier tube by immediately discharging the energy stored in the power supply to others when arcing occurs inside the tube. When a two-system power supply system is used as shown in FIG. 1c, two systems of high-speed discharge protection devices are also required.
FIG. 2 shows an example in which two systems of high-speed discharge protection devices are used. In FIG. 2, when the discharge tubes 11 and 14 receive a trigger, if the discharge start time of the discharge tube 14 is later than that of the discharge tube 11, or if the trigger system of the discharge tube 14 is broken and the discharge does not occur, the capacitor 12
The charge of the capacitor 15 is discharged and the voltage decreases, but because the discharge of the capacitor 15 is delayed or not discharged, the collector voltage of the amplifier tube increases, and a dangerous voltage exceeding the absolute maximum rating is generated, damaging not only the amplifier tube but also other circuit components. There is also a risk of destruction.

An object of the present invention is to install a high-speed discharge protection device using a diode in a modulator that operates a multipole amplifier tube using two power sources to prevent burnout of the tube when arcing occurs in the tube. An object of the present invention is to provide a high-speed discharge protection device which solves the above-mentioned disadvantages by connecting two power sources so that they operate in common.

That is, the high-speed discharge protection device according to the present invention detects the discharge tube that discharges in response to an external trigger, the resistor that limits the arcing current or discharge current, and the abnormal current in the modulator that operates the multi-pole amplifier tube using two power sources. It consists of a current detection circuit that generates a trigger, a trigger drive circuit that drives the trigger that operates the discharge tube, and a diode that allows one discharge tube to discharge two power supplies in common. This is a high-speed discharge protection device that uses diodes to form a common discharge circuit to cause discharge in the tube.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 3 shows a system diagram of a multi-pole amplifier tube power amplification circuit which includes the fast discharge protection device according to the present invention as one of its constituent elements.

The fast discharge protection device basically comprises a discharge tube 11, current limiting resistors 17, 18, 19 and 20, a diode 23, a current detection circuit 21, and a trigger driver 22. Resistors 19 and 20 are connected in series with capacitor 12 for the purpose of limiting the arcing current in case arcing occurs between the cathode and the body, and similarly resistors 17 and 18 are connected in series with the capacitor 12 in order to limit the arcing current in case arcing occurs between the collector and the body. It is connected in series with capacitor 15 for the purpose of limiting arcing current. The discharge tube 11, the capacitor 12 and the resistor 20 constitute one loop, and the discharge tube 11, the resistors 18 and 20, the capacitor 15 and the diode 2
3 are also connected to form one loop.

The basic operation of FIG. 3 will be described below. When a normal heater voltage is applied to the amplifier tube from the heater power supply 10, a negative bias voltage is applied to the grid from the grid modulator 2, and the two power supplies 16 and 13 operate. The cathode potential of the amplifier tube is the charging voltage of capacitor 12 V1
The collector potential becomes -V1 + V2, which is higher than the cathode potential by the charging voltage V2 of the capacitor 15. When a positive driving voltage is applied to the grid from the grid modulator 2, electrons are emitted from the cathode and the amplifier tube performs a power amplification function.

If arcing occurs between the cathode and the body, the charge stored in the capacitor 12 passes through a loop constituted by the body cathode, the resistors 19 and 20, and the capacitor 12, and starts discharging.
Then, the current detector detects an abnormal current and operates the trigger driver 22 to apply a trigger to the discharge tube 11. When the discharge tube 11 is discharged, the charge in the capacitor 12 is discharged through a loop composed of the capacitor 12, the discharge tube 11, and the resistor 20, so that arcing inside the amplifier tube disappears and burnout of the amplifier tube is prevented.

Further, when the discharge tube 11 is discharged and the charging voltage V1 of the capacitor 12 becomes smaller than the charging voltage V2 of the capacitor 15 (V1<V2), the charge in the capacitor 15 starts discharging via the diode 23. Therefore, by forming a common discharge circuit using diodes for the smoothing capacitors of the two power supplies, it is possible to discharge the power energy of two systems of one system of the high-speed discharge protection device.

As explained above, the present invention connects the discharge loop of one power supply system to another power supply system through a diode, thereby making it possible to discharge the power energy of two systems with one high-speed discharge protection device. This has the effect of preventing voltage exceeding the absolute maximum rating from being generated when the high-speed discharge protection device operates. Additionally, since the two required high-speed discharge protection devices can be combined into one, the device can be made smaller and lighter, reducing cost and improving reliability by reducing the number of circuit components.

[Brief explanation of drawings]

Figures 1 a to c are system diagrams showing the power supply system in a typical modulation circuit for a multipole amplifier tube; Figure 2 is a circuit diagram showing a conventional example of a modulation circuit for a multipole amplifier tube; The figure is a system diagram of a circuit showing an embodiment of the present invention. 1...Multipole amplifier tube, 2...Grid modulator,
3, 7, 17, 18, 19, 20...Resistor,
4,5,6,8,9...power supply system, 10...heater power supply, 11,14...discharge tube, 12,15...
Capacitor, 13, 16...power supply, 21...current detector, 22...trigger driver, 23...diode.

Claims (1)

[Claims] 1. In a modulator that operates a multipole amplifier tube using two power supplies, there is a means for detecting an abnormal current due to arcing in the tube of the multipole amplifier tube and generating a trigger signal, and a means for generating a trigger signal by detecting an abnormal current due to arcing in the tube of the multipole amplifier tube, and a means for generating a trigger signal by using energy charged in the power supply section. 1. A high-speed discharge protection device, comprising: means for causing a discharge by a discharge current; and means for limiting the discharge current to a specified value or less, and forming a common discharge between the two power supplies using diodes.