# US 10,455,677 B2 · X-ray generator and driving method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,455,677 B2 - Document ID: US10455677B2 - Status: Granted - Kind: B2 - Application number: 15/459,661 - Filed: 2017-03-15 - Published: 2017-11-30 - Granted: 2019-10-22 - Earliest claimed: 2016-05-25 - Assignees: Electronics and Telecommunications Research Institute - Applicants: Electronics and Telecommunications Research Institute - Inventors: Jun Tae Kang; Yoon-Ho Song; Jin-Woo Jeong - Web page: https://patentgrep.com/patent/US10455677B2 ## CPC - H05G 1/34: Anode current, heater current or heater voltage of X-ray tube - H01J 35/065: {Field emission, photo emission or secondary emission cathodes} - H05G 1/10: Power supply arrangements for feeding the X-ray tube {(supply circuits with converters in general H02M; supply circuits for emitters and amplifiers H04B1/16 - H04B1/1623)} - H05G 1/32: Supply voltage of the X-ray apparatus or tube - H05G: X-RAY TECHNIQUE (investigating or analysing materials by the use of X-rays G01N23/00; apparatus for X-ray photography G03B42/02; X-ray tubes H01J35/00; TV systems having X-ray input H04N5/321) - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract Provided is an X-ray generator including a thermal electron emission type X-ray generator configured to generate a negative high voltage and a filament current, a field electron emission type X-ray generator including an anode electrode to be grounded, and configured to use the negative high voltage to bias the cathode electrode, and a field emission current control unit configured to convert the filament current to generate an output voltage to be provided to a gate electrode of the field electron emission type X-ray generator and convert the filament current to fix, to a specific level, a level of an emission current flowing through the cathode electrode. ## Claims ### Claim 1 An X-ray generator comprising: a thermal electron emission type X-ray generator configured to generate a negative high voltage and a filament current; a field electron emission type X-ray generator comprising an anode electrode to be grounded and a cathode electrode, and configured to use the negative high voltage to bias the cathode electrode; and a field emission current control unit configured to convert the filament current to generate an output voltage to be provided to a gate electrode of the field electron emission type X-ray generator and convert the filament current to fix, to a specific level, a level of an emission current flowing through the cathode electrode. ### Claim 2 (depends on 1) The X-ray generator of claim 1, wherein the field emission current control unit comprises a first resistor configured to convert the filament current to an input voltage. ### Claim 3 (depends on 2) The X-ray generator of claim 2, wherein the field emission current control unit comprises a DC-DC converter configured to step up the input voltage to the output voltage. ### Claim 4 (depends on 2) The X-ray generator of claim 2, wherein the field emission current control unit comprises: a voltage regulator configured to convert the input voltage to a current controlled voltage of a static voltage; and a switch element configured to deliver the negative high voltage to the cathode electrode in response to the current controlled voltage. ### Claim 5 (depends on 4) The X-ray generator of claim 4, wherein the field emission current control unit comprises: a second resistor configured to divide the input voltage; and the voltage regulator is connected to the second resistor. ### Claim 6 (depends on 5) The X-ray generator of claim 5, wherein the switch element is provided as a transistor configured to deliver the negative high voltage to the cathode electrode, and the current controlled voltage is provided to a gate-source voltage of the transistor. ### Claim 7 (depends on 4) The X-ray generator of claim 4, wherein the voltage regulator is a Zener diode. ### Claim 8 (depends on 1) The X-ray generator of claim 1, wherein the field electron emission type X-ray generator receives, as a focusing voltage, a grid voltage of the thermal electron emission type X-ray generator. ### Claim 9 An X-ray generator comprising: a field electron emission type X-ray generator of which anode electrode is grounded; and a field emission current control unit configured to receive a source current to generate an output voltage to be provided to a gate electrode of the field electron emission type X-ray generator on a basis of a negative high voltage, and use the source current to control an emission current flowing through a cathode electrode of the field electron emission type X-ray generator, wherein the source current is a filament current of a thermal electron emission type X-ray generator. ### Claim 10 (depends on 9) The X-ray generator of claim 9, wherein the field emission current control unit uses a first resistor to convert the source current to an input voltage higher than the negative high voltage. ### Claim 11 (depends on 10) The X-ray generator of claim 10, wherein the field emission current control unit comprises a DC-DC converter configured to step up the input voltage to the output voltage. ### Claim 12 (depends on 10) The X-ray generator of claim 10, wherein the field emission current control unit comprises: a second resistor configured to divide the input voltage; and a Zener diode serially connected to the second resistor. ### Claim 13 (depends on 12) The X-ray generator of claim 12, wherein the field emission current control unit comprises an NMOS transistor configured to deliver the negative high voltage to the cathode electrode, wherein voltages divided to both terminals of the Zener diode are provided as a gate-source voltage of the NMOS transistor. ### Claim 14 (depends on 9) The X-ray generator of claim 9, wherein the field electron emission type X-ray generator receives a grid voltage of the thermal electron emission type X-ray generator and provides the grid voltage to a focusing electrode of the field electron emission type X-ray generator. ### Claim 15 A method for driving a field electron emission type X-ray generator of which an anode electrode is grounded, the method comprising: receiving a negative high voltage and a filament current from a thermal electron emission type X-ray generator; converting the filament current to generate an output voltage to be provided to a gate electrode of the field electron emission type X-ray generator; converting the filament current to generate a current controlled voltage for controlling an emission current flowing through a cathode electrode of the field electron emission type X-ray generator; and providing the output voltage to the gate electrode and applying the current controlled voltage as a gate-source voltage of a transistor configured to deliver the negative high voltage to the cathode electrode of the field electron emission type X-ray generator. ### Claim 16 (depends on 15) The method of claim 15, wherein the generating of the output voltage comprises: using a resistor to convert the filament current to an input voltage; and stepping up the input voltage to generate the output voltage. ### Claim 17 (depends on 16) The method of claim 16, wherein in the generating of the current controlled voltage, the current controlled voltage is generated by dividing the input voltage and using a Zener diode to convert the divided voltage to a static voltage. ### Claim 18 (depends on 15) The method of claim 15, further comprising: receiving a grid voltage of the thermal electron emission type X-ray generator to provide the grid voltage to a focusing electrode of the field electron emission type X-ray generator.