X-ray generator using tetrode tubes as switching elements
AssigneeKabushiki Kaisha Toshiba
InventorsMitsuru Yahata, Hidetoshi Kudo
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Abstract
The anode and cathode of an X-ray tube are connected to a high-voltage power source respectively, through corresponding tetrode tubes, and the center metal electrode of the X-ray tube is grounded. The tetrode tubes are simultaneously turned on and off upon receipt of a control signal. An abnormal current, which flows through the center metal electrode due to a short-circuiting fault of the tetrode tube connected to the cathode of the X-ray tube, is detected during an OFF period of the tetrode tubes. Upon detection of the abnormal current, the tetrode tube connected to the anode of the X-ray tube is forcedly turned on, thus preventing the fusion of the center metal electrode in the X-ray tube.
Claims5
An X-ray generator comprising:
- an X-ray tube having an anode, cathode, and grounded center metal electrode;
- a first high-voltage power source connected to said anode of said X-ray tube, to apply a positive high voltage to said anode of said X-ray tube;
- a second high-voltage power source connected to said cathode of said X-ray tube, to apply a negative high voltage to said cathode of said X-ray tube;
- first switching means connected between said first high-voltage power source and said anode of said X-ray tube;
- second switching means connected between said second high-voltage power source and said cathode of said X-ray tube;
- control-signal supply means connected to said first and second switching means, for supplying a control signal for simultaneously turning said first and second switching means on and off;
- abnormal-current detection means connected to said first and second high-voltage power sources, for detecting an abnormal current flowing through said X-ray tube;
- and
- protection circuit means connected to said abnormal-current detection means, for causing at least the control signal supply means to stop the supply of the control signal to said first and second switching means, upon receipt of the detection of the abnormal current, the improvement wherein
- said abnormal-current detection means generates a short-circuiting fault detection signal indicative of a short-circuiting fault of said second switching means, in response to an abnormal current flowing through said center metal electrode of said X-ray tube, due to the short-circuiting fault of said second switching means, which fault may arise during an OFF period of said first and second switching means;
- and
- means is further provided for subsequently supplying a turn-on signal to at least said first switching means, in response to the short-circuiting fault detection signal from said abnormal-current detection means, to cause said first switching means to be turned on.
Dependencies are inferred from the claim text.