Radio frequency power delivery system

• US 8,710,926 B2
• Filed: 02/08/2012
• Issued: 04/29/2014
• Est. Priority Date: 10/31/2005
• Status: Active Grant

• Current Assignee: MKS Instruments Incorporated
• Original Assignee: MKS Instruments Incorporated
• Inventors: Nagarkatti, Siddharth P., Barskiy, Yevgeniy, Tian, Feng, Bystryak, Ilya
• Primary Examiner(s): A, Minh D
• Application Number:
  US13/368,920
• Publication Number:
  US 20120262064A1
• Time in Patent Office: 811 Days
• Field of Search: 315/111.21, 333/17.2, 333/17.3, 333/18, 333/254, 333/291, 333/292, 330/254, 330/291, 330/292
• US Class Current: 330/254
• 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 37/32183 Matching circuits
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/321 Use of a microprocessor in an amplifier circuit or its control circuit
• CPC Class Codes: H03F 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 2200/391 the output circuit of an amplifying stage comprising an LC-network
• CPC Class Codes: H03F 2200/393 A measuring circuit being coupled to the output of an amplifier
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 3/195 in integrated circuits
• 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: H03H 7/40 Automatic matching of load impedance to source impedance

Abstract

A system and method are provided for delivering power to a dynamic load. The system includes a power supply providing DC power having a substantially constant power open loop response, a power amplifier for converting the DC power to RF power, a sensor for measuring voltage, current and phase angle between voltage and current vectors associated with the RF power, an electrically controllable impedance matching system to modify the impedance of the power amplifier to at least a substantially matched impedance of a dynamic load, and a controller for controlling the electrically controllable impedance matching system. The system further includes a sensor calibration measuring module for determining power delivered by the power amplifier, an electronic matching system calibration module for determining power delivered to a dynamic load, and a power dissipation module for calculating power dissipated in the electrically controllable impedance matching system.

Claims

1. A hybrid system for delivering power to a load, comprising;

a power converter system that delivers RF power to a load;

an outer loop coupled to the power converter system for compensating for nonlinearities in the power converter system, wherein the outer loop receives the delivered RF power as an input; and

an inner loop coupled to the power converter system to provide a gain-bandwidth and a phase margin for substantially maintaining the stability of the delivered RF power, wherein the inner loop receives an analog current set point output from the outer loop as an input.

2. The system of claim 1, wherein the inner loop is an analog control loop.

3. The system of claim 2, wherein the analog control loop includes an analog control, and an output conditioning block for regulating output power.

4. The system of claim 1, wherein the outer loop is a digital control loop.

5. The system of claim 4, wherein the digital control loop includes:

an analog-to-digital converter for converting an analog measurement taken at the power converter to a digital measurement for determining a digital current set point;

a digital control to output the digital current set point for determining a pulse width modulation signal; and

a digital-to-analog converter for converting the digital current set point to an analog current set point for determining the pulse width modulation signal for regulating output power.

6. The system of claim 5, wherein the analog control loop outputs the pulse width modulated signal based on the analog current set point and an analog measurement taken at the power converter system for regulating output power.

7. The system of claim 5, wherein the power converter system includes a DC source, and a RF power amplifier.

8. The system of claim 7, wherein a RF power measurement taken at the RF power amplifier is digitized by the analog-to-digital converter to produce a digital RF power measurement for determining a pulse width modulation signal for regulating output power.

9. The system of claim 8, wherein the digital control outputs a digital current set point for determining the pulse width modulation signal for regulating output power.

10. The system of claim 9, wherein the digital current set point is converted to a analog current set point for determining the pulse width modulation signal for regulating output power.

11. The system of claim 10, wherein the analog control loop outputs the pulse width modulated signal based on the analog current set point and an analog current set point measurement taken at the DC source for regulating output power.

12. A digital and analog hybrid method for delivering power to a load, comprising:

receiving a delivered RF power signal as an input to an outer loop coupled to a power converter system, wherein the outer loop compensates for nonlinearities in the in the output power;

receiving an analog current set point output from the outer loop as an input to an inner loop coupled to the power converter system; and

providing a gain-bandwidth and a phase margin to substantially maintain stability of the delivered RF power.

13. The method of claim 12, further comprising:

measuring delivered RF power signal;

converting the measured delivered RF power from an analog signal to a digital delivered RF power signal; and

determining a digital current set point from the digital delivered RF power signal and a RF power set point.

14. The method of claim 13, further comprising:

converting the digital current set point from a digital signal to an analog current set point signal;

measuring DC current at a power supply; and

determining a duty cycle command from the analog current set point signal and the DC current.

15. The method of claim 14, further comprising:

determining a pulse width modulation signal from the duty cycle command; and

regulating the power supply with the pulse width modulation signal.

16. A digital and analog hybrid system for delivering power to a load, comprising:

means for receiving a delivered RF power signal as an input to an outer loop coupled to a power converter system, wherein the outer loop compensates for nonlinearities in the in the output power;

means for receiving an analog current set point output from the outer loop as an input to an inner loop coupled to the power converter system; and

means for providing a gain-bandwidth and a phase margin to substantially maintain stability of the delivered RF power.