JPH0831592A - X-ray tube filament heating circuit - Google Patents

Abstract

PURPOSE:To simplify the constitution of a filament heating circuit by making arms, performing the same action in inverters taking charge of plural filaments respectively, and control circuits, performing the switching action of the arms, common with each other. CONSTITUTION:The switching elements 201, 204, 206, 202, 203, and 205 of respective first to third arms 2A, 2B, and 2C repeat in order turning-on/-off at phase differences respectively by output from first to third arm switching control circuits 3A, 3B, and 3C. This flows an A.C., in the primary sides of first and second transformers 4A and 4B to optionally set electric power to the first and second filaments 6A and 6B of the X-ray tube 5 by pressure-risen output, to be supplied. These filament heating circuits make the arm 2A, performing the same action in respective inverters, and the control circuit 3A, performing the switching action of the arm, common with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray tube filament heating circuit, and more particularly to an X-ray tube filament heating circuit for heating each filament of an X-ray tube having a plurality of filaments.

[0002]

2. Description of the Related Art For example, in an X-ray diagnostic apparatus, the X-ray tube is usually equipped with two filaments.

Such filaments are classified into those for large focus and those for small focus, and these are switched and used.

That is, the X-ray diagnostic apparatus has a fluoroscopic stage and a radiographic stage in its operation, and it is determined whether or not the subject is placed in a predetermined radiographic region by fluoroscopy, and it is determined to be good. If it is done, the picture is taken.

Therefore, the X-ray dose from the X-ray tube is relatively small during fluoroscopy, and the X-ray dose from the X-ray tube is relatively large during radiography.

In this case, in order to prevent the shortage of the X-ray tube current, preheating is performed to raise the temperature of the filament in a short time at a high speed, and the filament currently used is main heated. The filament on the unused side is preheated.

Therefore, an X-ray tube filament heating circuit for heating these filaments is provided with an inverter and a transformer in charge of each filament, and each inverter is controlled by its control circuit to heat each filament. It controls the condition.

[0008]

However, as described above, the X-ray tube filament heating circuit configured as described above is provided with the inverter and the transformer in charge of each filament. Therefore, there has been a demand for further simplification of the circuit.

The present invention has been made under such circumstances, and an object of the present invention is to provide an X-ray tube filament heating circuit having a simple circuit configuration.

[0010]

In order to achieve such an object, the present invention basically comprises a DC power source, an inverter for controlling the conversion of this DC power source into an AC current, and an output from this inverter. A transformer for transforming, and supplying an output from the transformer to a filament of an X-ray tube, the X-ray tube being provided with a plurality of filaments, and an inverter in charge of each filament according to the filament. In the X-ray tube filament heating circuit, each inverter is provided with a transformer, and each inverter is configured by connecting two arms each including two switching elements connected in series in parallel. It is characterized in that the arm for performing the operation and the control circuit for performing the switching operation of the arm are configured in common. .

[0011]

According to the X-ray tube filament heating circuit having such a structure, the arm performing the same operation in each inverter and the control circuit performing the switching operation of the arm are configured in common. It becomes possible to eliminate one arm and its control circuit in the inverter as compared with the conventional one.

Therefore, from the above, it is possible to simplify the circuit configuration.

[0013]

1 is a circuit diagram showing an embodiment of an X-ray tube filament heating circuit according to the present invention.

In FIG. 1, first, there is a DC power source 1,
The DC voltage from the DC power source 1 is converted into an AC voltage by the inverter 2.

The inverter 2 has a first arm 2A composed of switching elements 201 and 202 connected in series between the DC power supplies 1 and a second arm 2B composed of switching elements 203 and 204 connected in series between the DC power supplies 1. And a third arm 2C composed of switching elements 205 and 206 connected in series between the DC power supply 1 and a flywheel diode connected between the respective switching elements.

The ON / OFF of each switching element is controlled by the inverter control circuit 3, and the inverter control circuit 3 controls the ON / OFF of each switching element of the first arm 2A. 3A, a second arm switching control circuit 3B that controls ON / OFF of each switching element of the second arm 2B, and a third arm switching control circuit that controls ON / OFF of each switching element of the third arm 2C. 3C and.

An alternating current is applied between the intermediate connection point of the first arm 2A and the intermediate connection point of the second arm 2B by the on / off timing of each switching element of the inverter 2 which will be described later by the inverter control circuit 3 as described above. This alternating current is generated and supplied to the first filament 6A of the X-ray tube 5 via the first transformer 4A and also to the first arm 2A.
AC is generated between the intermediate connection point of the second arm 4C and the intermediate connection point of the third arm 2C, and this alternating current is supplied to the second filament 6B of the X-ray tube 5 via the second transformer 4B. There is.

FIG. 2 is a time chart showing the timing of turning on / off each switching element of the inverter 2 and the waveform diagram of the input supplied to each of the transformers 4A and 4B.

In FIG. 1, first, the output from the first arm switching control circuit 3A (FIG. 2A) turns on the switching element 201 of the first arm 2A (at this time, the switching element 202 is turned off). ).

After that, the output from the second arm switching control circuit 3B (FIG. 2 (b)) causes the switching element 204 of the second arm 2B to turn on with a delay of the phase difference φ1 (at this time, the switching element 20).
3 is off). As a result, the current from the DC power supply 1 flows through the switching element 201, the first transformer 4A, and the switching element 204 (FIG. 2 (d)).

Then, the output from the third arm switching control circuit 3C (FIG. 2 (c)) causes the switching element 206 of the third arm 2C to turn on with a delay of the phase difference φ2 (at this time, the switching element 20).
5 is off). As a result, the current from the DC power supply 1 flows through the switching element 201, the second transformer 4B, and the switching element 206 (FIG. 2 (e)).

Further, the output from the first arm switching control circuit 3A (FIG. 2 (a)) is used to output the first arm 2A.
The switching element 202 is turned on (at this time, the switching element 201 is turned off).

After that, the output from the second arm switching control circuit 3B (FIG. 2B) causes the switching element 203 of the second arm 2B to turn on with a delay of the phase difference ψ1 (at this time, the switching element 20).
4 is off). As a result, the current from the DC power supply 1 flows through the switching element 203, the first transformer 4A, and the switching element 202 (FIG. 2 (d)).

Further, the output from the third arm switching control circuit 3C (FIG. 2 (c)) causes the switching element 205 of the third arm 2C to turn on with a delay of the phase difference ψ2 (at this time, the switching element 20).
6 is off). As a result, the current from the DC power supply 1 flows through the switching element 205, the second transformer 4B, and the switching element 202 (FIG. 2 (e)).

After that, the above-mentioned operation is sequentially repeated.

As a result, an alternating current flows through the primary side of each of the first transformer 4A and the second transformer 4B, and the output boosted by the first transformer 4A is supplied to the first filament 6A of the X-ray tube 5. The output boosted by the second transformer 4B is supplied to the second filament 6B of the X-ray tube 5. In this case, the phase differences φ1 and φ1 can be controlled in the second arm switching control circuit 3B and the second arm switching control circuit 3C, respectively, whereby the electric power can be set arbitrarily.

According to the X-ray tube filament heating circuit shown in such an embodiment, the arm (first arm 2A) that performs the same operation in each inverter and the control circuit (the first arm 2A) that performs the switching operation of the arm (first arm 2A). Since the arm switching control circuits 3A) are made common to each other, it is possible to eliminate one arm and its control circuit in the inverter as compared with the conventional one.

Therefore, the circuit structure can be simplified from the above.

In the above-described embodiment, the heating circuit for the X-ray tube having two filaments has been described, but it is also applicable to the heating circuit for the X-ray tube having more filaments. There is no end. In this case, 6 pairs of arms can be made into 4 pairs in the case of having 3 filaments, and 8 pairs of arms can be made to be 5 pairs in the case of having 4 filaments. Like

[0030]

As is apparent from the above description,
According to the X-ray tube filament heating circuit of the present invention, the structure can be simplified.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an X-ray tube filament heating circuit according to the present invention.

FIG. 2 is a time chart showing the operation of the circuit of FIG.

[Explanation of symbols]

 2 Inverter 3 Inverter control circuit 4 Transformer 5 X-ray tube 6 Filament

Claims (1)

[Claims] 1. A direct current power supply, an inverter for converting and controlling this direct current power supply into an alternating current, and a transformer for transforming the output from this inverter, and the output from this transformer is supplied to a filament of an X-ray tube. The X-ray tube is provided with a plurality of filaments, an inverter and a transformer in charge of each filament are provided accordingly, and each inverter is composed of two switching elements connected in series. In an X-ray tube filament heating circuit configured by connecting two arms in parallel, the arm performing the same operation in each inverter and the control circuit performing the switching operation of the arm are commonly configured. Characteristic X-ray tube filament heating circuit.