JP2519710B2 - De-queuing circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention stabilizes the charging voltage of a pulse shaping circuit used in a line type pulse modulation circuit or the like in a radar device such as ASR or ARSR. De-queuing (De
-Q'ing) circuit.

(Prior Art) In a conventional pulse forming circuit (Pulse Forming Network: PFN circuit) used in a line type pulse modulation circuit, a de-queuing circuit stabilizes the charging voltage V _PFN. I am trying.

FIG. 3 shows its configuration, where 11 is a line type pulse modulation circuit and 12 is a dequeuing circuit.

The line type pulse modulation circuit 11 is composed of a PFN circuit 111, a thyratron 112, and a pulse transformer 113.
Generates a high voltage pulse V _PFN from the charging current i _PFN by in advance by applying a high-pressure pulse V _PFN to the primary winding N1 of the thyratron 112 and pulse transformer 113, depending on the transmission trigger St supplied to the grid of thyratron 112 The pulse transformer 113 pulse-modulates the output of the secondary winding N2 of the pulse transformer 113.

The de-queuing circuit 12 includes a charging choke 121, a hold-off diode 122, a high voltage divider 123, a comparator 124 and a CR.
It is composed of a resonance circuit 125 and a thyristor 126. Secondary winding n2 of charging choke 121, CR resonance circuit 125 and thyristor 126
Forms a feedback loop, and when the thyristor 126 is turned on, the current id generated in the secondary winding n2 of the charging choke 121 flows in the CR resonance circuit 125.
The hold-off diode 122 is for preventing backflow. The high voltage divider 123 is the charging voltage V _{PFN of the} PFN circuit 111.
Is _divided and output, and the divided level is compared with the reference voltage V _REF by the comparator 124. Then, when the voltage division level becomes equal to or higher than the reference voltage level, the dequeuing trigger Qt is generated to control the thyristor 126 to the on state.

FIG. 4 shows an example of the operation. (A) The figure shows the transmission trigger S
t, (b) figure is charging voltage V _PFN , (c) figure is charging current
i _PFN , (d) figure shows the _dequeuing current id, and (e) figure shows the output waveform of the dequeuing trigger Qt.
In the figure, the waveform of the solid line shows the case where the de-queuing circuit 12 is in the driving state, and the waveform of the dotted line shows the case where the de-queuing circuit 12 is in the stopped state.

That is, the charging current i _PFN supplied to the PFN circuit 111 flows only in one direction by the hold-off diode 122 as shown in FIG.
Is a pulsating flow having a predetermined sine wave that is generated at the generation timing of. By forcibly setting i _PFN to 0, V _PFN can be held at the current charging voltage.

The dequeuing circuit 12 is a circuit that operates based on such a principle. That is, the de-queuing trigger Qt is generated when the charging voltage V _PFN reaches the V1 level as shown in FIG. 4 (e). This de queuing
By setting the thyristor 126 connected in parallel to the secondary side of the charging choke 121 by the trigger Qt to the ON state, the energy of i _PFN flowing in the charging choke 121 can be consumed by the resistor R. . The current id flowing into the de-queuing circuit 11 decreases to 0 before the next charging of the PFN circuit 111 starts, as shown in FIG. 4 (d), and turns off the thyristor 126. Therefore, the charging voltage V _PFN of the PFN circuit 111 becomes constant at a predetermined voltage level V1 as shown in FIG. 4 (b).

However, in the conventional de-queuing circuit as described above, when an abnormality such as a decrease in the reference voltage V _{REF or} an increase in the charging voltage V _PFN occurs, the de-queuing circuit as shown in FIG. The trigger Qt generation timing moves forward (in the direction of the arrow in the figure). When the thyristor 126 is turned on by this trigger Qt, the de-queuing is applied too deeply as shown by the dotted line in FIG.
A large current may flow into the queuing circuit 12 and damage the parts.

(Problems to be Solved by the Invention) As described above, in the conventional de-queuing circuit, the generation timing of the de-queuing trigger is unlimited, so that the reference voltage decreases, the PFN charging voltage increases, etc. If the abnormal condition occurs, a large current may flow in the circuit and the parts may be damaged.

The present invention has been made to solve the above problems, and even if an abnormality such as a decrease in the reference voltage or an increase in the PFN charging voltage occurs, a large current does not flow in the circuit, thereby preventing damage to parts. It is an object of the present invention to provide a de-queuing circuit capable of performing.

[Configuration of the Invention] (Means for Solving the Problems) In order to achieve the above object, a dequeuing circuit according to the present invention is a pulse shaping circuit for charging a pulsating charge current to generate a high-voltage pulse. And a de-queuing circuit for stabilizing the charging voltage of the pulse shaping circuit, which is used in a pulse modulating circuit that includes a pulse modulating means that modulates and outputs the high voltage pulse in response to a transmission trigger. De-queuing trigger generation means for generating a de-queuing trigger by detecting that the charging voltage has risen to a predetermined level or higher, and is activated and preset by a synchronous trigger synchronized with the transmission trigger. A gate circuit that outputs a gate signal only for a time, a gate signal output from this gate circuit, and the dequeuing trigger are input, and the dequeue Ing trigger causes pass intact when fed out gate signal input period, and de queuing limiting circuit for outputting after the gate signal input period when it is fed into the gate signal input period, this de
Switching means that is turned on by a de-queuing trigger output from the queuing limiting circuit,
The switching means is turned on to pull in the charging current to interrupt the charging current to the pulse shaping circuit, thereby stabilizing the charging voltage of the pulse shaping circuit. In consideration of the charging time constant of the pulse shaping circuit, the gate signal output time of the circuit is set to the time required for the charging current to drop from the peak to the allowable level of the parts in the circuit.

(Operation) The de-queuing circuit having the above-described configuration generates the de-queuing trigger when the charge voltage of the pulse shaping circuit becomes equal to or higher than a predetermined level. The gate signal is output for a preset time. And de queuing
When the trigger is supplied outside the gate signal input period, it is sent to the switching means as it is, and when it is supplied within the gate signal input period, it is sent to the switching means after the set time of the gate signal output has passed, and the switching means is turned on. , It draws the charging current and shuts off the charging current to the pulse shaping circuit. As a result, the charging voltage of the pulse shaping circuit can be stabilized. In this case, the gate signal output time of the gate circuit is set to the time required for the charging current to fall to the allowable level of the parts in the circuit in consideration of the charging time constant of the pulse shaping circuit. No dequeuing trigger is supplied to the switching means. In addition, even if the charging voltage rises abnormally or the reference level decreases and a de-queuing trigger occurs within the above period, an excessive current does not flow in the circuit components including the switching means. The risk of destruction can be eliminated.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows a configuration in which the present invention is applied to the circuit shown in FIG. 3. In FIG. 1, the same parts as those in FIG. 3 are designated by the same reference numerals and the de-queuing circuit part is extracted. The other parts are omitted.

That is, the dequeuing limiting circuit 127 and the gate circuit 128 are added to this dequeuing circuit. The gate circuit 128 generates a dequeuing gate signal DQG which becomes high level for a predetermined period T when the synchronous trigger Dt synchronized with the transmission trigger St is input, and this DQC is a dequeuing limiting circuit 127. Supplied to the limiting input. The dequeuing limiting circuit 127 delays and outputs the output of the comparator 126, which is supplied while the gate signal DQG is being input, after the gate signal DQC is input.

 The operation of the above configuration will be described below.

FIG. 2 shows an example of the operation. (A) is a transmission trigger St, (b) is a charging voltage V _PFN , (c) is a charging current i _PFN , and (d) is a de-queue. Ing current id, (e)
The figure shows the dequeuing gate signal DQG, and the figure (f) shows the output waveform of the dequeuing trigger Qt. The solid line in the figure shows the waveform when the dequeuing circuit 12 is in the drive state. The dotted line waveform shows the case where the dequeuing circuit 12 is in a stopped state.

That is, when the synchronous trigger Dt is input to the gate circuit 128 at the timing of the transmission trigger St shown in FIG. 2A, the de-queuing signal which becomes high level for a predetermined period T from the time of trigger input from the gate circuit 128. Gate signal
DQG is output. The period T is set by the time the charging current i _PFN drops to a level sufficient to compensate the components of the dequeuing circuit 12.

Here, the charging voltage V _PFN of the PFN circuit 111 and the reference voltage V _REF
When is a normal value, the same operation as the conventional one is performed as shown in FIGS. That is, the de-queuing trigger Qt output from the comparator 124 is generated after the de-queuing gate signal DQG goes low, so the trigger Qt passes through the de-queuing limiting circuit 127 as it is. Supplied to the thyristor 127, and the thyristor 1
26 is turned on.

Next, if the reference voltage V _REF drops, the high voltage divider 123
Output reaches the reference voltage V _REF earlier than normal state,
The de-queuing trigger signal Qt is generated within the high level period of the de-queuing gate signal DQG as shown by the dotted line in FIG. However, this de-queuing trigger Qt is limited by the de-queuing limiting circuit 127, and is delayed and output after the gate signal DQC is input, as shown by the solid line in the figure. This kind of operation is the charging voltage V
_The same applies when the _PFN rises abnormally.

Therefore, in the de-queuing circuit having the above configuration, the current id at a level at which the components in the circuit are damaged does not flow, so even if deep de-queuing is attempted, the value will not exceed the preset value. In this way, it is possible to protect the circuit components and prevent the voltage from rising to the load.

[Effects of the Invention] As described above, according to the present invention, even when an abnormality such as a decrease in the reference voltage or an increase in the PFN charging voltage occurs, a large current does not flow in the circuit, thereby preventing damage to parts. It is possible to provide a de-queuing circuit capable of performing the above.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of the dequeuing circuit according to the present invention, FIG. 2 is a timing chart for explaining the operation of the embodiment, and FIG. 3 is a conventional dequeuing circuit. FIG. 4 is a block circuit diagram showing the configuration of a pulse modulation circuit using a circuit, and FIG. 4 is a timing diagram for explaining the operation of the conventional circuit. 11 ... Pulse modulation circuit, 111 ... PFN circuit, 112 ... Thyratron, 113 ... Pulse transformer, 12 ... De-queuing circuit, 121 ... Charging choke, 122 ... Hold-off diode, 123 ... High voltage Voltage divider, 124 …… Comparator, 12
5 …… CR resonance circuit, 126 …… thyristor, 127 …… thyristor, 128 …… gate circuit, St …… transmission trigger, Dt ……
Sync trigger, Qt ... De-queuing trigger, V _PFN ...
… Charging voltage, V _REF …… Reference voltage, i _PFN …… Charging current, DQ
G: De-queuing gate signal.

Claims (1)

(57) [Claims] 1. A pulse modulation circuit comprising a pulse shaping circuit for charging a pulsating current to generate a high voltage pulse, and a pulse modulation circuit for modulating and outputting the high voltage pulse according to a transmission trigger. In a dequeuing circuit for stabilizing the charge voltage of the pulse shaping circuit, a dequeuing circuit that generates a dequeuing trigger by detecting that the charge voltage of the pulse shaping circuit exceeds a predetermined level. Trigger generation means, a gate circuit that is activated by a synchronous trigger synchronized with the transmission trigger and outputs a gate signal for a preset time, a gate signal output from the gate circuit, and
When a queuing trigger is input and the de-queuing trigger is supplied outside the gate signal input period, it is passed as it is, and when it is supplied within the gate signal input period, it is output after the gate signal input period. A queuing limiting circuit, a switching means that is turned on by a dequeuing trigger output from the dequeuing limiting circuit, and an ON operation of the switching means to draw the charging current to the pulse shaping circuit. A current drawing means for stabilizing the charging voltage of the pulse shaping circuit by interrupting the charging current of the pulse shaping circuit, the gate signal output time of the gate circuit, considering the charging time constant of the pulse shaping circuit, It is characterized by setting the time required for the charging current to drop from the peak to the allowable level of the parts in the circuit. Queuing circuit.