CN106873712B

CN106873712B - Radio frequency generator control circuit and radio frequency generator

Info

Publication number: CN106873712B
Application number: CN201710078057.7A
Authority: CN
Inventors: 耿束建; 薛年喜; 周航
Original assignee: Beijing Naura Microelectronics Equipment Co Ltd
Current assignee: Beijing Naura Microelectronics Equipment Co Ltd
Priority date: 2017-02-14
Filing date: 2017-02-14
Publication date: 2021-03-02
Anticipated expiration: 2037-02-14
Also published as: CN106873712A

Abstract

A radio frequency generator control circuit comprises a control module, a converter module and a power amplifier module, wherein the control module is provided with a DDS circuit and a comparator, the DDS circuit generates a radio frequency sinusoidal signal, and the radio frequency sinusoidal signal is converted into a square wave signal through the comparator and is transmitted to the power amplifier module; the control module is connected with the converter module, the control module controls the converter module to generate two paths of unipolar waveforms, and the converter module superposes and processes the two paths of unipolar waveforms to form direct-current voltage; the direct current voltage supplies power to the power amplification module, and the power amplification module outputs radio frequency current with adjustable power.

Description

Radio frequency generator control circuit and radio frequency generator

Technical Field

The invention belongs to the technical field of electronics, and particularly relates to a radio frequency generator control circuit and a radio frequency generator.

Background

The radio frequency generator is a plasma matched power supply and comprises a signal generator, an impedance matcher, an impedance power meter and the like, and the technical field of the radio frequency generator is a new high-tech field in China at the end of eighty years. The radio frequency generator has wide application, and the main specific fields are as follows: semiconductor manufacturing, plasma etching, vacuum coating, PECVD, plasma cleaning, Physical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), rf sputtering, and the like.

The modern radio frequency generator has been developed, and the tube power source of eighties has been developed step by step into the present transistor radio frequency generator, the power is from watt, hundred watt, kilowatt to megawatt, the frequency is 2Mhz/13.56Mhz/27.12Mhz/40.68Mhz, etc., and the application is also expanded from the former vacuum field to other fields, semiconductor, beauty, etc.

The signal generating and controlling circuit in the radio frequency generator is the core circuit of the radio frequency generator. The signal generation and control circuit in the rf generator has a great influence on the technical specifications of the rf generator.

Disclosure of Invention

The patent provides a signal generation and control circuit in a radio frequency generator, which changes the working frequency through Direct Digital Synthesis (DDS), and changes the power supply voltage of a power amplifier by adopting a phase-shifting waveform superposition method, thereby changing the output power of the radio frequency generator. The functions of setting, controlling, monitoring and the like of the radio frequency generator are realized.

The invention is realized by the following technical scheme:

a radio frequency generator control circuit comprises a control module, a converter module and a power amplifier module, wherein the control module is provided with a DDS circuit and a comparator, the DDS circuit generates a radio frequency sinusoidal signal, and the radio frequency sinusoidal signal is converted into a square wave signal through the comparator and is transmitted to the power amplifier module;

the control module is connected with a converter module, and the converter module comprises a V/F waveform generation module, a high-power MOSFET (metal-oxide-semiconductor field effect transistor), a coupling transformer and a rectifier bridge

The control module controls a V/F waveform generation module in the converter module to generate two paths of unipolar waveforms, and the two paths of unipolar waveforms form direct-current voltage after passing through a high-power MOSFET (metal-oxide-semiconductor field effect transistor), a coupling transformer and a rectifier bridge; the direct current voltage supplies power to the power amplification module, and the power amplification module outputs radio frequency current with adjustable power.

In a further improvement, the control module comprises an ARM chip and an FPGA chip, the ARM chip is used for controlling the DDS circuit, and the FPGA chip is used for sending waveform signals to the converter module.

In a further improvement, the FPGA chip is connected with a detection circuit, and the power amplifier module feeds back a power signal to the FPGA chip through the detection circuit to form closed-loop control.

In a further improvement, the ARM chip is connected with a display key interface, a parameter setting interface, a monitoring quantity AD sampling interface and a communication interface.

A radio frequency generator comprises a control module, a converter module and a power amplifier module, wherein the equipment generator comprises a power supply module which processes input three-phase power and supplies power to other modules;

the control module is provided with a DDS circuit and a comparator, the DDS circuit generates a radio frequency sinusoidal signal, and the radio frequency sinusoidal signal is converted into a square wave signal through the comparator and is transmitted to the power amplification module;

the control module is connected with the converter module, the control module controls the converter module to generate two paths of unipolar waveforms, and the converter module superposes and processes the two paths of unipolar waveforms to form direct-current voltage; the direct current voltage supplies power to the power amplification module, and the power amplification module outputs radio frequency current with adjustable power;

the power amplification module is connected with a measurement module, and the measurement module measures the output power of the power amplification module and feeds the output power back to the control module;

the control module is also connected with a display device and a human-computer interaction device.

Compared with the prior art, the invention has the following advantages:

the signal generating and controlling circuit provided by the patent can be applied to various radio frequency generators, the working frequency is changed by using Direct Digital Synthesis (DDS), and the power supply voltage of a power amplifier is changed by adopting a phase-shifting waveform superposition method, so that the output power of the radio frequency generator is changed. The functions of setting, controlling, monitoring and the like of the radio frequency generator are realized.

Drawings

FIG. 1 is a schematic block diagram of a radio frequency generator;

FIG. 2 is a schematic diagram of a signal generation and control circuit;

FIG. 3 is a unipolar V/F signal waveform;

FIG. 4 drive signal waveforms;

FIG. 5 is a waveform of a high power MOSFET output signal;

FIG. 6 shows two MOSFET signals with a 180-degree difference and coupled out through a transformer;

FIG. 7 shows two MOSFET signals with a phase difference of more than 180 degrees are coupled and output through a transformer;

FIG. 8 shows that after rectification by the rectifier bridge, a positive polarity pulse waveform is output;

FIG. 9 shows the DC voltage signal output after the filter circuit;

fig. 10 automatic closed loop control of output power.

Detailed Description

Example 1

Fig. 1 is a schematic block diagram of a radio frequency generator, the radio frequency generator of the present invention includes:

a power supply module: the power supply module rectifies the three-phase electricity to generate power supplies required by other modules.

A converter module: the converter module converts the +/-150V direct-current power supply rectified by the power supply module into power supply voltage required by the radio frequency power amplifier. The converter module includes: the V/F waveform generating module is used for generating two paths of unipolar waveforms; the high-power MOSFET is used for amplifying the voltages of the two paths of unipolar waveforms; the coupling transformer is used for coupling the two paths of unipolar waveforms into pulse waves; and the rectifier bridge is used for converting the coupled pulse wave into a direct-current voltage signal.

A power amplifier module: the power amplification module amplifies the power of the signal sent by the control module.

A control module: the DDS is configured and arranged by a chip in the control module to generate a sine wave signal source with required frequency and amplitude, so that the phase of a driving signal of the converter is controlled. And each part of the whole radio frequency generator is monitored, so that the cyclic acquisition monitoring of the monitoring quantity, the setting of working parameters, the man-machine interaction and the like are realized.

A measurement module: the measuring module provides forward power and reflected power monitoring analog quantity.

An interaction and display module: the interaction and display module is communicated with the control panel through a serial port to control the front panel keyboard and the LCD screen to display.

Fig. 2 is a schematic diagram of a control module, in which an ARM chip mainly implements configuration of a DDS, generates a required radio frequency sinusoidal signal, and outputs a square wave signal through a comparator. The FPGA chip has the main function of changing the power supply voltage of a power amplifier by using a phase-shifting waveform superposition method through a converter module, so that the output power of the radio frequency generator is changed.

Fig. 3-9 are schematic diagrams of converter module output voltages:

the converter V/F waveform generation module can output two paths of unipolar waveforms with phase difference of 180 degrees as shown in figure 3 according to signals of the FPGA chip. Fig. 4 is a unipolar drive signal waveform.

The drive signal drives the high power MOSFET transistor to generate a bipolar high voltage signal waveform as shown in fig. 5. Two high-power MOSFET output signals are coupled by a transformer and then output, and when the phase difference of the two signals is 180 degrees, the transformer coupling output is 0V, as shown in figure 6.

When the phase difference of the two paths of signals exceeds 180 degrees, the transformer couples and outputs a bipolar pulse signal, and the width of the pulse signal is increased along with the increase of the phase difference. As shown in fig. 7.

The bipolar pulse signal coupled and output by the transformer is rectified by the rectifier bridge and then outputs a positive pulse waveform, as shown in fig. 8. The positive polarity pulse waveform is output and then the dc voltage signal is output after passing through the filter circuit, as shown in fig. 9. The direct current voltage can supply power to the power amplification module.

Therefore, the FPGA chip can control the direct-current voltage finally output by the converter module by changing the phase difference between the two paths of unipolar waveforms. The direct current voltage can affect the final output power of the power amplification module, and the power is adjustable.

The detection module can realize closed-loop control of the equipment, and the principle of the closed-loop control is shown in fig. 10: the power amplifier output signal feeds back a power signal to the PWM detection circuit after passing through the measurement circuit. The circuit generates a pulse signal with variable width according to the change of the feedback power signal, and the phase of the output waveform of the converter V/F is changed in the FPGA according to the width change of the pulse signal, so that the direct-current voltage of the power amplifier power supply is changed, and the effect of changing the output power is achieved. To this end, a closed loop control of the power regulation is formed.

Claims

1. A radio frequency generator control circuit comprises a control module, a converter module and a power amplifier module, and is characterized in that the control module is provided with a DDS circuit and a comparator, the DDS circuit generates a radio frequency sinusoidal signal, and the radio frequency sinusoidal signal is converted into a square wave signal through the comparator and is transmitted to the power amplifier module;

the control module is connected with the converter module, and the converter module comprises a V/F waveform generation module, a high-power MOSFET (metal-oxide-semiconductor field effect transistor), a coupling transformer and a rectifier bridge;

the control module controls a V/F waveform generating module in the converter module to generate two paths of unipolar waveforms, the converter V/F waveform generating module can output two paths of unipolar waveforms with the phase difference of 180 degrees according to signals of the control module, when the control module controls the two paths of signals to exceed 180 degrees, the transformer couples and outputs a bipolar pulse signal, the width of the pulse signal is increased along with the increase of the phase difference, and the transformer couples and outputs the bipolar pulse signal and supplies power to the power amplification module after the bipolar pulse signal is rectified by the rectifier bridge.

2. The rf generator control circuit of claim 1, wherein the control module includes an ARM chip for controlling the DDS circuit and an FPGA chip for sending the waveform signal to the converter module.

3. The rf generator control circuit of claim 2, wherein the FPGA chip is connected to a detection circuit, and the power amplifier module feeds back a power signal to the FPGA chip through the detection circuit to form a closed-loop control.

4. The radio frequency generator control circuit according to claim 2, wherein the ARM chip is connected to a display key interface, a parameter setting interface, a monitoring amount AD sampling interface, and a communication interface.

5. A radio frequency generator comprises a control module, a converter module and a power amplifier module, and is characterized by comprising a power supply module, wherein the power supply module processes input three-phase power and supplies power to other modules;