High voltage pulsed power supply with time limiting nonlinear feedback
First Claim
1. A high voltage pulsed direct current power supply for an X-ray rube, comprising:
- a step-up transformer having a primary winding and a secondary winding;
a primary circuit including in series a source of direct current, the transformer primary winding, and switching means operable by electrical pulses for interrupting the direct current and inducing a high voltage alternating current in said secondary winding, said switching means including pulse generating means for periodically generating the electrical pulses at a high frequency;
a secondary circuit including in series the transformer secondary winding and rectifying means for converting the high voltage alternating current to high voltage direct current; and
nonlinear feedback means coupled between said rectifying means and said pulse generating means for controlling the generation of the electrical pulses in accordance with the high voltage direct current, said nonlinear feedback means including a loop switch to close when the high voltage direct current is greater than a predetermined voltage.
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Accused Products
Abstract
An apparatus for supplying high voltage pulsed direct current to an X-ray tube includes a transformer, a high frequency inverter circuit and a nonlinear feedback loop. The invention uses the high frequency inverter connected in series with a DC power supply source and the primary winding of the transformer in order to generate high voltage, high frequency AC in the secondary winding. A rectifier connected to the secondary winding supplies high voltage pulsed DC to the X-ray tube. A detector, such as a voltage divider, detects the voltage supplied to the X-ray tube and supplies a representation of it to a nonlinear feedback circuit connected between the detector and the high frequency inverter. The inverter circuit includes at least one switch generated by electrical pulses. The nonlinear feedback circuit controls the duty cycle of the inverter during only a portion of the output voltage range of the high voltage pulsed power supply, preferably only after the output voltage reaches 90% of the rated high voltage to be supplied to the X-ray tube.
38 Citations
11 Claims
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1. A high voltage pulsed direct current power supply for an X-ray rube, comprising:
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a step-up transformer having a primary winding and a secondary winding; a primary circuit including in series a source of direct current, the transformer primary winding, and switching means operable by electrical pulses for interrupting the direct current and inducing a high voltage alternating current in said secondary winding, said switching means including pulse generating means for periodically generating the electrical pulses at a high frequency; a secondary circuit including in series the transformer secondary winding and rectifying means for converting the high voltage alternating current to high voltage direct current; and nonlinear feedback means coupled between said rectifying means and said pulse generating means for controlling the generation of the electrical pulses in accordance with the high voltage direct current, said nonlinear feedback means including a loop switch to close when the high voltage direct current is greater than a predetermined voltage. - View Dependent Claims (2, 3)
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4. Apparatus for supplying high voltage direct current to an X-ray emitting device, comprising:
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a high frequency inverter connectable to a source of direct current, said inverter including switching means for interrupting the direct current at a high frequency to produce high frequency alternating current; a transformer connected to said inverter to increase the voltage of the high frequency alternating current; rectifying means connected to said transformer for converting the increased voltage alternating current to high voltage direct current; and nonlinear feedback means for controlling the operation of said switching means comprising detecting means to detect the high voltage direct current, an error amplifier to generate an error signal in response to the detected high voltage direct current, loop switching means for supplying the error signal to said high frequency inverter when said loop switching means is closed and for denying the error signal to said high frequency inverter when said loop switching means is open, and means for closing said loop switching means when the detected high voltage direct current is greater than a predetermined voltage. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11)
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Specification