Apparatus for controlled overshoot in a RF generator

• US 10,074,518 B2
• Filed: 01/25/2017
• Issued: 09/11/2018
• Est. Priority Date: 02/18/2016
• Status: Active Grant

• Current Assignee: AES Global Holdings Pte Ltd. (Advanced Energy Industries, Inc. (China))
• Original Assignee: Advanced Energy Industries Incorporated
• Inventors: Van Zyl, Gideon
• Primary Examiner(s): Tan, Vibol
• Application Number:
  US15/415,597
• Publication Number:
  US 20170243723A1
• Time in Patent Office: 594 Days
• CPC Class Codes: H01J 37/32146 Amplitude modulation, includes pulsing
• CPC Class Codes: H01J 37/32183 Matching circuits
• CPC Class Codes: H02J 9/00 Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
• CPC Class Codes: H02M 3/155 using semiconductor devices only
• CPC Class Codes: H03F 1/0244 Stepped control
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 3/189 High-frequency amplifiers, e.g. radio frequency amplifiers
• CPC Class Codes: H03F 3/20 Power amplifiers, e.g. Class B amplifiers, Class C amplifiers H03F3/26 - H03F3/30 take precedence
• CPC Class Codes: H03F 3/245 with semiconductor devices only

Abstract

A radio-frequency (RF) generator is provided that produces a controlled overshoot. One embodiment includes a RF power amplifier and a direct-current (DC) power supply that includes a primary DC power supply, an auxiliary DC power supply, a half-bridge circuit, and a control circuit. The half-bridge circuit, in a first switching state, electrically connects, in series, the auxiliary DC power supply with the primary DC power supply and, in a second switching state, electrically disconnects the auxiliary DC power supply from the primary DC power supply. The control circuit places the half-bridge circuit in the first switching state for a first period of time and places the half-bridge circuit in the second switching state for a second period of time to produce a controlled overshoot in the power produced by the RF generator throughout the first period of time.

Claims

1. A radio-frequency (RF) generator, comprising:

a RF power amplifier; and

a direct-current (DC) power supply electrically connected with the RF power amplifier to supply electrical power to the RF power amplifier, the DC power supply including;

a primary DC power supply;

an auxiliary DC power supply;

a half-bridge circuit that, in a first switching state, applies power to the RF power amplifier by electrically connecting, in series, the auxiliary DC power supply with the primary DC power supply and that, in a second switching state, electrically disconnects the auxiliary DC power supply from the primary DC power supply while applying power from the primary DC power supply to the RF power amplifier; and

a control circuit that places the half-bridge circuit in the first switching state for a first period and that places the half-bridge circuit in the second switching state for a second period to produce a controlled overshoot in the power produced by the RF generator throughout the first period,

wherein the first period begins at a leading edge of a power pulse produced by the RF generator and the second period immediately follows the first period.

2. The RF generator of claim 1, wherein the RF power amplifier is a balanced RF power amplifier.

3. The RF generator of claim 1, wherein at least one of the primary DC power supply and the auxiliary DC power supply is variable.

4. The RF generator of claim 1, wherein the RF generator directly or indirectly supplies power to a plasma load through one or more matching networks.

5. The RF generator of claim 1, wherein the controlled overshoot in the power produced by the RF generator is used for plasma ignition.

6. The RF generator of claim 1, wherein the first and second periods are followed by zero, one, or a plurality of additional periods during which the RF generator produces a different amount of power than during the first and second periods.

7. The RF generator of claim 1, wherein the first, second, and any additional periods repeat in a predetermined pattern to form a pulse train.

8. The RF generator of claim 1, wherein the control circuit is configured to determine the first period by observing a change in the properties of a load connected with an output of the RF generator.

9. A radio-frequency (RF) generator, comprising:

a RF power amplifier; and

a direct-current (DC) power supply electrically connected with the RF power amplifier to supply electrical power to the RF power amplifier, the DC power supply including;

a primary DC power supply;

an auxiliary DC power supply;

a half-bridge circuit that, in a first switching state, electrically connects, in series, the auxiliary DC power supply with the primary DC power supply and that, in a second switching state, electrically disconnects the auxiliary DC power supply from the primary DC power supply; and

a control circuit that includes a non-transitory, tangible, machine-readable medium encoded with instructions to perform a method, the method including;

placing the half-bridge circuit in the first switching state for a first period, beginning at a leading edge of a power pulse produced by the RF power amplifier, to produce, for plasma ignition, a controlled overshoot in the power produced by the RF generator throughout the first period; and

placing the half-bridge circuit in the second switching state for a second period, the second period immediately following the first period.

10. The RF generator of claim 9, wherein the first and second periods are followed by zero, one, or a plurality of additional periods during which the RF generator produces a different amount of power than during the first and second periods.

11. The RF generator of claim 9, wherein the first, second, and any additional periods repeat in a predetermined pattern to form a pulse train.

12. The RF generator of claim 9, wherein the first period is fixed.

13. The RF generator of claim 9, wherein the method further includes:

determining the first period by observing a change in the properties of a load connected with an output of the RF generator.

14. The RF generator of claim 9, wherein the RF generator directly or indirectly supplies power to a plasma load through one or more matching networks and the controlled overshoot in the power produced by the RF generator is used for plasma ignition.

15. A radio-frequency (RF) generator, comprising:

means for amplifying RF power;

means for supplying direct-current (DC) power to the means for amplifying RF power, the means for supplying DC power including primary means for supplying DC power and auxiliary means for supplying DC power;

means for switching that, in a first switching state, electrically connects, in series, the auxiliary means for supplying DC power with the primary means for supplying DC power and that, in a second switching state, electrically disconnects the auxiliary means for supplying DC power from the primary means for supplying DC power; and

means for controlling the means for switching that places the means for switching in the first switching state for a first period, beginning at a leading edge of a power pulse produced by the means for amplifying RF power, and that places the means for switching in the second switching state for a second period, immediately following the first period, to produce, for plasma ignition, a controlled overshoot in the power produced by the RF generator throughout the first period.

16. The RF generator of claim 15, wherein the means for controlling the means for switching is configured to cause the first and second periods to be followed by zero, one, or a plurality of additional periods during which the RF generator produces a different amount of power than during the first and second periods.

17. The RF generator of claim 15, wherein the means for controlling the means for switching is configured to cause the first, second, and additional periods to repeat in a predetermined pattern to form a pulse train.

18. The RF generator of claim 15, wherein the first period is fixed.

19. The RF generator of claim 15, wherein the means for controlling the means for switching is configured to determine the first period by observing a change in the properties of a load connected to an output of the RF generator.

20. The RF generator of claim 15, wherein the RF generator directly or indirectly supplies power to a plasma load through one or more matching networks.