High voltage generating device for X-ray apparatus
First Claim
1. A high voltage generating device for an X-ray apparatus comprising:
- a rectifier circuit for rectifying an AC voltage from a power source;
a smoothing circuit for smoothing a rectified output from said rectifier circuit, said smoothing circuit having first and second terminals connected to corresponding output terminals of said rectifier circuit, and comprising a series circuit of first and second capacitors connected between said first and second terminals;
a high voltage transformer having primary and secondary windings;
a resonant circuit having a third capacitor and said primary winding of said high voltage transformer which are connected in series configuration;
a current switching circuit for permitting first and second currents which correspond to the voltages of said first and second capacitors respectively, to pass through the resonant circuit, said current switching circuit having first and second switching sections, said first switching section being connected at one terminal to said first terminal and at the other terminal to a junction of said first and second capacitors through said resonant circuit, and said second switching section being connected at one terminal to said junction of said first and second capacitors through said resonant circuit and at the other terminal to said second terminal;
resonant circuit driving means for alternately driving said first and second switching sections, said resonant circuit driving means comprising a current detector for detecting a resonant current flowing through said resonant circuit, means for detecting zero-cross points of the resonant current detected by said current detector and providing zero-cross-point detection signals, and phase control means responsive to said zero-cross-point detection signals for alternately supplying first and second gate pulses to said first and second switching sections;
means for applying an X-ray tube voltage between an anode and a cathode filament of an X-ray tube, said applying means being connected between a secondary winding of said high voltage transformer and said X-ray tube and including means for rectifying and smoothing an AC voltage induced across said secondary winding; and
voltage switching means for permitting the DC voltage output of said smoothing circuit to be switched to one of a plurality of levels, said voltage switching means delivering an output voltage at least to said rectifier circuit.
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Accused Products
Abstract
A high voltage generating device for an X-ray apparatus includes a DC output voltage control device for rectifying and smoothing a commercial AC power source voltage and a resonant circuit comprised of a series circuit of a capacitor and a primary winding of a transformer. The output DC voltage of the DC output voltage control device is supplied to the resonant circuit in a first direction or in a direction opposite to the first direction. The direction in which the voltage is applied to the resonant circuit is switched by a current switching means. Consequently, a high AC voltage is obtained through a secondary winding of the transformer. The AC voltage is converted by a rectifying/smoothing means to an X-ray tube voltage which is applied between an anode and a cathode filament of an X-ray tube. The DC output voltage control device permits its output voltage to be switched to an arbitrary level.
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Citations
7 Claims
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1. A high voltage generating device for an X-ray apparatus comprising:
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a rectifier circuit for rectifying an AC voltage from a power source; a smoothing circuit for smoothing a rectified output from said rectifier circuit, said smoothing circuit having first and second terminals connected to corresponding output terminals of said rectifier circuit, and comprising a series circuit of first and second capacitors connected between said first and second terminals; a high voltage transformer having primary and secondary windings; a resonant circuit having a third capacitor and said primary winding of said high voltage transformer which are connected in series configuration; a current switching circuit for permitting first and second currents which correspond to the voltages of said first and second capacitors respectively, to pass through the resonant circuit, said current switching circuit having first and second switching sections, said first switching section being connected at one terminal to said first terminal and at the other terminal to a junction of said first and second capacitors through said resonant circuit, and said second switching section being connected at one terminal to said junction of said first and second capacitors through said resonant circuit and at the other terminal to said second terminal; resonant circuit driving means for alternately driving said first and second switching sections, said resonant circuit driving means comprising a current detector for detecting a resonant current flowing through said resonant circuit, means for detecting zero-cross points of the resonant current detected by said current detector and providing zero-cross-point detection signals, and phase control means responsive to said zero-cross-point detection signals for alternately supplying first and second gate pulses to said first and second switching sections; means for applying an X-ray tube voltage between an anode and a cathode filament of an X-ray tube, said applying means being connected between a secondary winding of said high voltage transformer and said X-ray tube and including means for rectifying and smoothing an AC voltage induced across said secondary winding; and voltage switching means for permitting the DC voltage output of said smoothing circuit to be switched to one of a plurality of levels, said voltage switching means delivering an output voltage at least to said rectifier circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification