DRIVING SWITCHES OF A PLASMA LOAD POWER SUUPLY

• US 20100171428A1
• Filed: 01/14/2010
• Published: 07/08/2010
• Est. Priority Date: 07/23/2007
• Status: Active Grant

• Current Assignee: Hüttinger Elektronik GmbH + Co. KG
• Original Assignee: Hüttinger Elektronik GmbH + Co. KG
• Inventors: Knaus, Hanns-Joachim, Windisch, Hans-Juergen, Kirchmeier, Thomas, Glueck, Michael
• Granted Patent: US 8,482,205 B2
• Time in Patent Office: Days
• US Class Current: 315/111.210
• CPC Class Codes: G01R 21/06 by measuring current and voltage G01R21/08 - G01R21/133 take precedence
• CPC Class Codes: G01R 23/02 Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
• CPC Class Codes: H01J 37/32045 Circuits specially adapted for controlling the glow discharge
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections
• CPC Class Codes: H02M 7/5383 in a self-oscillating arrangement H02M7/538 takes precedence
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance
• CPC Class Codes: H05B 41/2806 with semiconductor devices and specially adapted for lamps without electrodes in the vessel, e.g. surface discharge lamps, electrodeless discharge lamps
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

Operation of a plasma supply device having at least one switching bridge with at least two switching elements, and configured to deliver a high frequency output signal having a power of >500 W and a substantially constant fundamental frequency>3 MHz to a plasma load is accomplished by determining at least one operating parameter, at least one environmental parameter of at least one switching element and/or a switching bridge parameter, determining individual drive signals for the switching elements taking into account the at least one operating parameter, the at least one environmental parameter and/or the switching bridge parameter, and individually driving the switching elements with a respective drive signal.

Claims

1. A method of operating a power supply delivering a high frequency output signal having a power of more than 500 W and a substantially constant fundamental frequency greater than 3 MHz to a plasma load, the method comprising:

determining an operating parameter, an environmental parameter of a switching element or a switching bridge parameter;

generating individual drive signals for at least two switching elements of a switching bridge of the power supply, as a function of the determined operating parameter, environmental parameter, or switching bridge parameter; and

individually driving the switching elements of the power supply with respective ones of the generated drive signals in normal operation of the power supply.

2. The method of claim 1, wherein determining the operating parameter, environmental parameter or switching bridge parameter comprises determining an electrical parameter.

3. The method of claim 2, wherein determining the electrical parameter comprises determining an amount of electrical current flowing through one of the switching elements, a voltage at one of the switching elements, a current path, or a voltage profile.

4. The method of claim 1, wherein determining the operating parameter, environmental parameter or switching bridge parameter comprises determining a temperature of one of the switching elements, as the environmental parameter.

5. The method of claim 1, wherein determining the operating parameter, environmental parameter or switching bridge parameter comprises determining a parameter indicative of a load impedance seen by the switching bridge, as the switching bridge parameter.

6. The method of claim 1, wherein individually driving the switching elements comprises variably driving the switching elements and analyzing a resulting change in the operating parameter, environmental parameter, or switching bridge parameter.

7. The method of claim 1, wherein individually driving the switching elements comprises briefly switching at least one of the switching elements on during a portion of the switching cycle when the switching element is normally open.

8. The method of claim 1, wherein one or more of the switching elements are maintained in a nonconductive state for one or more periods of the fundamental frequency.

9. A power supply configured to generate an output power greater than 500 W at a substantially constant fundamental frequency greater than 3 MHz, and to deliver a high-frequency output signal to a plasma load, by which, at least upon mismatching, reflected power is returned to the power supply, the power supply comprising:

a drive signal generator, which drives at least two drivers;

a switching bridge having at least two switching elements, each switching element associated with a respective one of the drivers; and

at least one sensor connected to the drive signal generator and responsive to an operating parameter, a switching element environmental parameter, a switching bridge parameter, or a combination thereof;

wherein the power supply is configured such that, when the power supply is operated in normal operation while at least indirectly connected to a plasma load, and the drive signal generator generates individual drive signals for the switching elements as a function of input from the sensor.

10. The power supply of claim 9, wherein one of the drivers and the associated switching element are arranged in a common housing.

11. The power supply of claim 9, wherein the switching elements and associated drivers are arranged in the form of a half bridge within a common housing.

12. The power supply of claim 9, wherein the switching elements and associated drivers are arranged in the form of a full bridge within a common housing.

13. The power supply of claim 9, wherein the drive signal generator drives drivers for all of the switching elements.

14. The power supply of claim 9, wherein the drive signal generator is in the form of a digital module.

15. The power supply of claim 14, wherein the digital module is a DSP.

16. The power supply of claim 9, further comprising an A/D converter connected downstream of the sensor.

17. The power supply of claim 9, wherein the switching bridge is a first switching bridge, the power supply further comprising a second switching bridge, and wherein outputs of the first and second switching bridges are coupled by way of a coupler.