Apparatus for controlled overshoot in a RF generator
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.
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, 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 places the half-bridge circuit in the first switching state for a first period of time and that 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;
wherein the first and second periods of time are followed by zero, one, or a plurality of additional periods of time during which the RF generator produces a different amount of power than during the first and second periods of time.
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. 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 of time to produce a controlled overshoot in the power produced by the RF generator throughout the first period of time; and
placing the half-bridge circuit in the second switching state for a second period of time;
wherein the first and second periods of time are followed by zero, one, or a plurality of additional periods of time during which the RF generator produces a different amount of power than during the first and second periods of time.
7. The RF generator of claim 6 , wherein the first period of time begins at a leading edge of a power pulse produced by the RF generator and the second period of time immediately follows the first period of time.
8. The RF generator of claim 6 , wherein the first, second, and additional periods of time repeat in a predetermined pattern to form a pulse train.
9. The RF generator of claim 6 , wherein the first period of time is fixed.
10. The RF generator of claim 6 , wherein the method further includes:
determining the first period of time by observing a change in the properties of a load connected with an output of the RF generator.
11. The RF generator of claim 6 , 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.
12. 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 of time and that places the means for switching 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, and is further configured to cause the first and second periods of time are followed by zero, one, or a plurality of additional periods of time during which the RF generator produces a different amount of power than during the first and second periods of time.
13. The RF generator of claim 12 , wherein the means for controlling the means for switching is configured to cause the first period of time to begin at a leading edge of a power pulse produced by the RF generator and to cause the second period of time to follow immediately the first period of time.
14. The RF generator of claim 12 , wherein the means for controlling the means for switching is configured to cause the first, second, and additional periods of time to repeat in a predetermined pattern to form a pulse train.
15. The RF generator of claim 12 , wherein the first period of time is fixed.
16. The RF generator of claim 12 , wherein the means for controlling the means for switching is configured to determine the first period of time by observing a change in the properties of a load connected to an output of the RF generator.
17. The RF generator of claim 12 , wherein the RF generator directly or indirectly supplies power to a plasma load through one or more matching networks.
18. The RF generator of claim 12 , wherein the controlled overshoot in the power produced by the RF generator is used for plasma ignition.