JPH04324298A - X-ray generating device - Google Patents

Abstract

PURPOSE:To obtain an X-ray generating device whereby maximum tube voltage can be ensured even when power supply impedance is different. CONSTITUTION:In the case of a device which generates an X-ray by obtaining DC high voltage by an inverter circuit 3, with an AC input power supply 1 controlled by a pulse width control circuit 7, to supply this DC high voltage to an X-ray tube 5, an impedance detecting circuit 10 for detecting impedance of the input power supply is provided to control the above-mentioned pulse width control circuit based on an output of this impedance detecting circuit.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for generating X-rays by supplying a high voltage to an X-ray tube.

0002

2. Description of the Related Art A conventional X-ray generator will be explained with reference to the circuit diagram of FIG.

The X-ray generator shown in the figure includes a main transformer TR1 connected to an AC input power source 1 such as a commercial power source, and transistors Q1 and Q2 that perform switching by inputting a rectified and smoothed signal from the main transformer TR1. and an inverter circuit 3 consisting of an inverter transformer TR2, an X-ray tube 5 to which the secondary high voltage of the inverter circuit 3 is supplied,
A voltage detection circuit 6 for detecting this high voltage, an error amplifier 7B having two inputs, the output of this voltage detection circuit 6 and the output of the voltage setter 8, and a transistor Q1 of the inverter circuit based on the output of this error amplifier. , Q2.

0004

In the conventional device having the above structure, the maximum pulse width is set so that the maximum tube voltage can be obtained with the power supply impedance being specified.

[0005] However, in mobile X-ray apparatuses for surgical operations, the connected input power sources may differ, and therefore the power supply impedances also differ. Therefore, an abnormal state occurs in which the maximum tube voltage is not guaranteed, causing problems such as destruction of the apparatus itself or the X-ray tube.

SUMMARY OF THE INVENTION An object of the present invention is to provide an X-ray generator that can ensure a maximum tube voltage even if the power source impedance is different.

[Configuration of the invention]

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention obtains a DC high voltage from an AC input power source by an inverter circuit controlled by a pulse width control circuit, and supplies this to an X-ray tube. The apparatus for generating X-rays is characterized in that an impedance detection circuit for detecting the impedance of an input power source is provided, and the pulse width control circuit is controlled based on the output of the impedance detection circuit.

[0009]

[Operation] Even if the power source impedance changes, this is detected by the impedance detection circuit and fed back to the pulse width control circuit to control the pulse width, so that the maximum tube voltage is guaranteed.

0010

[Examples] The present invention will be explained in detail with reference to Examples below.

FIG. 1 is a circuit diagram showing an embodiment of the present invention, which includes a main transformer TR1 to which an input power source 1 is connected, a rectifier 2 for rectifying the secondary voltage of the main transformer TR1, and a smoothing capacitor C1. , two transistors Q1 and Q2 that input this rectified and smoothed signal, and an inverter transformer TR.
2, an inverter circuit 3 consisting of an inverter transformer T
A voltage detection circuit 6 consisting of a rectifier 4 that rectifies the high voltage of R2, an X-ray tube 5 to which the high voltage from the rectifier 4 is supplied, and bleeder resistors R1 and R2 that detect this high voltage.
The output of this voltage detection circuit 6 and the output of the voltage setting device 8 are
Based on the input error amplifier 7B and the output of this error amplifier 7B, the transistors Q1,
It has a pulse width control circuit 7 consisting of a comparator 7A for controlling the drive pulse width of Q2, and these configurations are substantially the same as the conventional device.

In the present invention, an impedance detection circuit 10 is particularly provided at the connection portion of the input power source 1. This consists of a dummy resistor RD connected between the terminals of the input power source 1, a rectifier 10A that rectifies the AC voltage obtained between the dummy resistor RD, and a voltage detection device connected between the output terminal of this rectifier 10A and the ground terminal. The detection output of the detection resistor Rf is sent to the comparator 7A of the pulse width control circuit 7.
is supplied to the control terminal of the

According to the device configured as described above, the voltage of the input power source 1 is stepped up by the main transformer TR1 and inputted to the inverter circuit 3, and the voltage of the input power source 1 is stepped up by the main transformer TR1 and input to the inverter circuit 3.
2, a high voltage is output from the inverter transformer TR2, and based on this, the X-ray tube 5
X-rays are generated from At this time, the maximum tube voltage supplied to the X-ray tube is determined by the pulse width supplied to transistors Q1 and Q2 of the inverter circuit 3 based on the relationship between the value set by the voltage setting device 8 and the output voltage from the voltage detector 6. will be controlled and guaranteed.

If the input power source 1 is changed to one with a different impedance, this change in power source impedance will be detected by the dummy resistor RD of the impedance detection circuit 10. The signal detected by this dummy resistor RD is fed back to the control terminal of the comparator 7A of the pulse width control circuit 7 via the voltage detection resistor Rf, and the output of the comparator 7A is adjusted to the pulse width in the direction that guarantees the maximum tube voltage. The control signal will be adjusted.

As a result, even if the power source impedance of the input power source changes, the maximum tube voltage is always guaranteed, and an abnormal condition that could destroy the device or the X-ray tube will not occur.

[0016]

According to the present invention described in detail above, it is possible to provide an X-ray generator that can guarantee the maximum tube voltage even if the power source impedance changes.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 is a circuit diagram showing a conventional device. 1 Input power supply 3 Inverter circuit 5. X-ray tube 7 Pulse width control circuit 10 Impedance detection circuit

Claims (1)

[Claims] [Claim 1] In a device that generates X-rays by obtaining a DC high voltage from an AC input power source by an inverter circuit controlled by a pulse width control circuit and supplying this to an X-ray tube, the impedance of the input power source is detected. An X-ray generator comprising an impedance detection circuit and controlling the pulse width control circuit based on the output of the impedance detection circuit.