System and Methods of Bimodal Automatic Power and Frequency Tuning of RF Generators

• US 20140097908A1
• Filed: 03/14/2013
• Published: 04/10/2014
• Est. Priority Date: 03/23/2012
• Status: Active Grant

• Current Assignee: MKS Instruments Incorporated
• Original Assignee: MKS Instruments Incorporated
• Inventors: FISK, Larry J. II, RUGHOONUNDON, Amish
• Granted Patent: US 8,952,765 B2
• Time in Patent Office: Days
• US Class Current: 331/15
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32174 Circuits specially adapted for controlling the RF discharge
• CPC Class Codes: H03B 5/1237 comprising means for varying the frequency of the generator
• 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: H03K 3/55 the switching device being a gas-filled tube having a control electrode

Abstract

A radio frequency generator includes a power control module, a frequency control module and a pulse generating module. The power control module is configured to generate a power signal indicating power levels for target states of a power amplifier. The frequency control module is configured to generate a frequency signal indicating frequencies for the target states of the power amplifier. The pulse generating module is configured to (i) supply an output signal to the power amplifier, (ii) recall at least one of a latest power level or a latest frequency for one of the target states of the power amplifier, and (iii) adjust a current power level and a current frequency of the output signal from a first state to a second state based on the power signal, the frequency signal, and at least one of the latest power level and the latest frequency of the power amplifier.

Claims

1. A radio frequency generator comprising:

a power control module configured to generate a power signal indicating power levels for a plurality of target states of a power amplifier;

a frequency control module configured to generate a frequency signal indicating frequencies for the plurality of target states of the power amplifier; and

a pulse generating module configured to (i) supply an output signal to the power amplifier, (ii) recall at least one of a latest power level and a latest frequency for one of the plurality of target states of the power amplifier, and (iii) adjust a current power level and a current frequency of the output signal from a first state to a second state based on the power signal, the frequency signal, and at least one of the latest power level and the latest frequency of the power amplifier.

2. The radio frequency generator of claim 1, wherein the pulse generating module is configured to (i) recall both the latest power level and the latest frequency, and (ii) adjust the output signal based on both the latest power level and the latest frequency.

3. The radio frequency generator of claim 1, wherein:

the pulse generating module is configured to provide (i) the power control module with the latest power level, and (ii) the frequency control module with the latest frequency;

the power control module is configured to generate the power signal based on the latest power level; and

the frequency control module is configured to generate the frequency signal based on the latest frequency.

4. The radio frequency generator of claim 1, wherein the pulse generating module is configured to adjust both the current power level and the current frequency during a single pulse of the power amplifier and based on the power signal, the frequency signal, the latest power level and the latest frequency.

5. The radio frequency generator of claim 1, wherein the pulse generating module is configured to adjust power levels and frequencies of each of consecutive pulses of the power amplifier based on the power signal, the frequency signal, the latest power level and the latest frequency.

6. The radio frequency generator of claim 1, wherein:

the pulse generating module configured to (i) wait a predetermined period after adjusting the current power level and the current frequency, (ii) in response to the predetermined period expiring, store an updated power level and an updated frequency of the power amplifier, and (iii) provide the updated power level to the power control module and the updated frequency to the frequency control module;

the power control module is configured to generate the power signal based on the updated power level; and

the frequency control module is configured to generate the frequency signal based on the updated frequency.

7. The radio frequency generator of claim 1, wherein the power generating module is configured to store updated power levels and updated frequencies for each of the plurality of target states.

8. The radio frequency generator of claim 1, further comprising the power amplifier and sensors, wherein:

the power amplifier is configured to receive the output signal;

the sensors are configured to detect power levels of power out of the power amplifier for each of the plurality of target states;

the frequency control module is configured to determines frequencies of the power out of the power amplifier based on indications of current pulse states, and

the power generating module is configured to store the detected power levels and frequencies as latest power levels and frequencies for the plurality of target states.

9. The radio frequency generator of claim 8, wherein:

the detect power levels and frequencies of the power out of the power amplifier are based on changes in impedance of a load of the power amplifier;

the power control module is configured to generate the power signal based on the detected power levels; and

the frequency control module is configured to generate the frequency signal based on the detected frequencies.

10. The radio frequency generator of claim 1, wherein, while the output signal is being transitioned from the first state to the second state, at least one of:

the power control module is configured to incrementally adjust the power signal to adjust the current power level to a target power level for the second state; and

the pulse generating module incrementally adjusts the current power level to a target power level for the second state.

11. The radio frequency generator of claim 1, wherein, while the output signal is being transitioned from the first state to the second state, at least one of:

the frequency control module is configured to incrementally adjust the frequency signal to adjust the current frequency to a target frequency for the second state; and

the pulse generating module incrementally adjusts the target frequency to the target frequency for the second state.

12. A method comprising:

generating a power signal indicating power levels for a plurality of target states of a power amplifier in a radio frequency generator;

generating a frequency signal indicating frequencies for the plurality of target states of the power amplifier;

supplying an output signal to the power amplifier;

recalling at least one of a latest power level and a latest frequency for one of the plurality of target states of the power amplifier; and

adjusting a current power level and a current frequency of the output signal from a first state to a second state based on the power signal, the frequency signal, and at least one of the latest power level and the latest frequency of the power amplifier.

13. The method of claim 12, further comprising:

recalling both the latest power level and the latest frequency; and

adjusting the output signal based on both the latest power level and the latest frequency.

14. The method of claim 12, further comprising providing (i) a power control module with the latest power level, and (ii) a frequency control module with the latest frequency, wherein:

the power control module is configured to generate the power signal based on the latest power level; and

the frequency control module is configured to generate the frequency signal based on the latest frequency.

15. The method of claim 12, further comprising adjusting both the current power level and the current frequency during a single pulse of the power amplifier and based on the power signal, the frequency signal, the latest power level and the latest frequency.

16. The method of claim 12, further comprising adjusting power levels and frequencies of each of consecutive pulses of the power amplifier based on the power signal, the frequency signal, the latest power level and the latest frequency.

17. The method of claim 12, further comprising:

waiting a predetermined period after adjusting the current power level and the current frequency;

in response to the predetermined period expiring, storing an updated power level and an updated frequency of the power amplifier;

generating the power signal based on the updated power level; and

generating the frequency signal based on the updated frequency.

18. The method of claim 12, further comprising storing updated power levels and updated frequencies for each of the plurality of target states.

19. The method of claim 12, further comprising:

receiving the output signal via the power amplifier;

via sensors, detecting power levels of power out of the power amplifier for each of the plurality of target states, wherein the detect power levels of the power out of the power amplifier are based on changes in impedance of a load of the power amplifier;

determining frequencies of the power out of the power amplifier based on indications of current pulse states;

storing the detected power levels and frequencies as latest power levels and frequencies for the plurality of target states;

generating the power signal based on the detected power levels; and

generating the frequency signal based on the detected frequencies.

20. The method of claim 12, wherein while the output signal is being transitioned from the first state to the second state:

incrementally adjusting the power signal to adjust the current power level to a target power level for the second state;

incrementally adjusting the current power level to a target power level for the second state;

incrementally adjusting the frequency signal to adjust the current frequency to a target frequency for the second state; and

incrementally adjusting the target frequency to the target frequency for the second state.