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US 8,526,574 B2Granted
Capacitor AC power coupling across high DC voltage differential
AssigneeMoxtek, Inc.
InventorsDongbing Wang, Dave Reynolds
Life of this patent
Estimating the term…
Abstract
A circuit providing reliable voltage isolation between a low and high voltage sides of a circuit while allowing AC power transfer between the low and high voltage sides of the circuit to an x-ray tube filament. Capacitors provide the isolation between the low and high voltage sides of the circuit.
Claims20
An x-ray source comprising:
- a) an evacuated dielectric tube;
- b) an anode, disposed at an end of the tube, including a material configured to produce x-rays in response to an impact of electrons;
- c) a cathode, disposed at an opposite end of the tube opposing the anode, including a cathode element;
- d) a power supply electrically coupled to the cathode element;
- e) the power supply comprising an alternating current (AC) circuit for supplying AC power to the cathode element in order to heat the cathode element, the AC circuit further comprising:
- i) an AC power source having a first and a second connection;
- ii) a first capacitor having a first connection and a second connection and a second capacitor having a first connection and a second connection;
- iii) the first connection of the AC power source connected to the first connection on the first capacitor and the second connection of the AC power source connected to the first connection on the second capacitor;
- iv) the AC power source, the first connection on the first capacitor, and the first connection on the second capacitor comprising a first voltage side of the circuit;
- v) the cathode element having a first connection and a second connection;
- vi) the second connection of the first capacitor connected to the first connection on the cathode element and the second connection of the second capacitor connected to the second connection on the cathode element;
- vii) the cathode element, the second connection on the first capacitor, and the second connection on the second capacitor comprising a second voltage side of the circuit;
- viii) the first and second capacitors providing voltage isolation between the first and second voltage sides of the circuit;
- and
- e) the power supply further comprising a high voltage direct current (DC) source connected to one of the first and second sides of the circuit and configured to provide a DC voltage differential between the first and second voltage sides of the circuit.
12 more elements
A circuit for supplying alternating current (AC) power to a load, the circuit comprising:
- a) an AC power source having a first and a second connection;
- b) a first capacitor having a first connection and a second connection and a second capacitor having a first connection and a second connection;
- c) the first connection of the AC power source connected to the first connection on the first capacitor and the second connection of the AC power source connected to the first connection on the second capacitor;
- d) the AC power source, the first connection on the first capacitor, and the first connection on the second capacitor comprising a first voltage side of the circuit;
- e) a load having a first connection and a second connection;
- f) the second connection of the first capacitor connected to the first connection on the load and the second connection of the second capacitor connected to the second connection on the load;
- g) the load, the second connection on the first capacitor, and the second connection on the second capacitor comprising a second voltage side of the circuit;
- h) the first and second capacitors providing voltage isolation between the first and second voltage sides of the circuit;
- and
- i) a high voltage direct current (DC) source connected to the one side of the circuit and configured to provide at least 1 kilovolt (kV) DC voltage differential between the first and second voltage sides of the circuit.
7 more elements
A circuit for supplying alternating current (AC) power to a load, the circuit comprising:
- a) an AC power source having a first and a second connection;
- b) a first capacitor having a first connection and a second connection and a second capacitor having a first connection and a second connection;
- c) the first connection of the AC power source connected to the first connection on the first capacitor and the second connection of the AC power source connected to the first connection on the second capacitor;
- d) the AC power source, the first connection on the first capacitor, and the first connection on the second capacitor comprising a first voltage side of the circuit;
- e) a load having a first connection and a second connection;
- f) the second connection of the first capacitor connected to the first connection on the load and the second connection of the second capacitor connected to the second connection on the load;
- g) the load, the second connection on the first capacitor, and the second connection on the second capacitor comprising a second voltage side of the circuit;
- h) the first and second capacitors providing voltage isolation between the first and second voltage sides of the circuit;
- i) a high voltage direct current (DC) source connected to the one side of the circuit and configured to provide at least 4 kilovolts (kV) DC voltage differential between the first and second voltage sides of the circuit;
- j) the AC power source transfers at least about 0.1 watts of power to the load;
- and
- k) the AC power source is configured to provide alternating current to the circuit at a frequency of at least about 1 MHz.
9 more elements
A method for heating a cathode filament in an x-ray tube, the method comprising:
- a) capacitively coupling an alternating current (AC) power supply to an x-ray tube filament;
- b) coupling a high voltage direct current (DC) power supply to the x-ray tube filament to provide a (DC) bias of at least four kilovolts (kV) between the filament and the AC power supply;
- and
- c) directing an alternating current at a selected frequency and power from the AC power supply across the capacitive coupling to the x-ray tube filament to heat the x-ray tube filament.
1 more element
Dependencies are inferred from the claim text.