Plasma density detection scanning power supply

Abstract

Relates to the technical field of plasma diagnosis, in particular to a plasma density detection scanning power supply which comprises a control circuit, a D / A converter, a scanning voltage generating circuit, a sampling circuit, a signal conditioning circuit and an A / D converter. A signal transmission pin of the control circuit is electrically connected with the upper computer, a power input pin of the control circuit is electrically connected with the power supply system, and a scanning signal output pin of the control circuit is electrically connected with the D / A converter; the output end of the D / A converter is electrically connected with the Langmuir probe through the scanning voltage generation circuit; the input end of the sampling circuit is electrically connected with the Langmuir probe, and the output end of the sampling circuit is electrically connected with the A / D converter through the signal conditioning circuit; the A / D converter is electrically connected with an input pin of the control circuit; the power supply is high in scanning speed and accurate in scanning result.

Description

Technical Field

[0001] The utility model relates to the technical field of plasma diagnosis, in particular to a plasma density detection scanning power supply. Background Art

[0002] The Langmuir probe is an important plasma density diagnostic tool. Compared with other methods, it has the advantages of simple structure and principle and the ability to measure a variety of plasma densities. Its basic principle is to extend a thin metal probe into the plasma, and then apply a scanning voltage from negative to positive to the probe through a scanning power supply to attract ions and electrons in the plasma, thereby forming a current on the probe; by measuring the probe voltage and current, the IV curve of the probe is obtained and analyzed and calculated to obtain relevant plasma parameters.

[0003] The scanning power supply is mainly used to generate scanning waveforms with adjustable bias, and its output voltage amplitude can reach ±500V. In addition, the traditional scanning power supply uses a switching power supply as the power supply output of the scanning system, and its output resolution and speed are relatively poor, and the scanning accuracy is low, which cannot meet the requirements of high-speed and high-precision scanning;

[0004] Chinese patent (CN106568805B) discloses a highly integrated Langmuir probe diagnostic system and method. The system uses tiny chips and devices to build circuits, which improves the system's integration and automation. The present invention uses tiny electronic chips and devices to build hardware circuits, and uses data processing on a computer to reduce the cost and volume of the system. The data acquisition unit is constructed with an FPGA controller as the core, which realizes high-speed synchronous data acquisition, as well as large-capacity data storage and communication, ensuring the real-time measurement. However, the system uses a single-chip microcomputer to drive the scanning unit to send a scanning signal, and then the FPGA receives the sampling signal. The two control units make the probe scanning process complicated, and the number of devices used becomes more, thereby affecting the diagnostic efficiency and production cost of the probe.

[0005] Therefore, we propose a scanning power supply that can scan quickly and obtain accurate results. Utility Model Content

[0006] In order to overcome the deficiencies in the background technology, the utility model discloses a plasma density detection scanning power supply.

[0007] In order to achieve the above-mentioned invention object, the utility model adopts the following technical solutions:

[0008] A plasma density detection scanning power supply comprises a control circuit, a D / A converter, a scanning voltage generating circuit, a sampling circuit, a signal conditioning circuit and an A / D converter;

[0009] The signal transmission end of the control circuit is electrically connected to the host computer, the power input end of the control circuit is electrically connected to the power supply system, and the scan signal output end of the control circuit is electrically connected to the D / A converter;

[0010] The output end of the D / A converter is electrically connected to the Langmuir probe via a scanning voltage generating circuit;

[0011] The input end of the sampling circuit is electrically connected to the Langmuir probe, and the output end of the sampling circuit is electrically connected to the A / D converter through the signal conditioning circuit;

[0012] The A / D converter is electrically connected to the input terminal of the control circuit.

[0013] Preferably, the control circuit includes an FPGA chip, a flash memory unit, a ROM memory unit, a network unit and a power management unit; wherein the data pins of the FPGA chip are electrically connected to the flash memory unit and the ROM memory unit respectively, the communication pins of the FPGA chip are electrically connected to the network unit, the power pins of the FPGA chip are electrically connected to the power management unit, the signal output pins of the FPGA chip are electrically connected to the D / A converter, and the signal input pins of the FPGA chip are electrically connected to the A / D converter; the network unit is signal-connected to the host computer, and the power management unit is electrically connected to the power system.

[0014] Preferably, the network unit is connected to the host computer signal via Modbus-TCP protocol.

[0015] Preferably, the FPGA chip is a chip of model XC3S50AN.

[0016] Preferably, the power supply system can convert external 220V AC high voltage electricity into 24V DC low voltage electricity.

[0017] Preferably, the control circuit is capable of sending a trigger signal to the D / A converter and the A / D converter.

[0018] Preferably, the A / D converter and the D / A converter both use 16-bit high-speed conversion chips.

[0019] Preferably, the scanning voltage generating circuit is configured as a PA89 high-voltage power operational amplifier.

[0020] Due to the adoption of the above-mentioned technical solution, the utility model has the following beneficial effects:

[0021] The utility model discloses a plasma density detection scanning power supply, 1. A single control circuit is used to realize the output of scanning signals and the input of sampling signals, thereby reducing the number of controllers, thereby shortening the scanning steps, and effectively improving the scanning speed and efficiency;

[0022] 2. The D / A converter and A / D converter are synchronously controlled by the control circuit to ensure the real-time and accuracy of sampling. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A structural schematic diagram of the utility model;

[0024] Figure 2 It is a structural diagram of the control circuit.

[0025] In the figure: 1. Control circuit; 11. FPGA chip; 12. Flash memory unit; 13. ROM memory unit; 14. Network unit; 15. Power management unit; 2. D / A converter; 3. Scan voltage generating circuit; 4. Sampling circuit; 5. Signal conditioning circuit; 6. A / D converter; 7. Power supply system; 8. Host computer; 9. Langmuir probe. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. In the description, it should be understood that if there are terms such as "upper", "lower", "front", "rear", "left", "right" and the like indicating directions or positional relationships, they are only corresponding to the drawings of the present invention, for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific direction:

[0027] Embodiment 1 is:

[0028] Combined with Figure 1-2 The plasma density detection scanning power supply comprises a control circuit 1, a D / A converter 2, a scanning voltage generating circuit 3, a sampling circuit 4, a signal conditioning circuit 5 and an A / D converter 6;

[0029] The signal transmission end of the control circuit 1 is electrically connected to the host computer 8, the power input end of the control circuit 1 is electrically connected to the power supply system 7, and the scan signal output end of the control circuit 1 is electrically connected to the D / A converter 2;

[0030] The host computer 8 is used to send a scanning parameter signal, which is a digital signal, and the scanning parameter signal includes parameters such as the amplitude, period and number of repetitions of the scanning voltage. After receiving the digital scanning parameter signal, the control circuit 1 outputs it to the D / A converter 2 for digital-to-analog conversion and then gives it to the scanning voltage generating circuit 3, and the host computer 8 can also receive the sampling processing signal sent by the control circuit 1; in addition, the power supply system 7 is used to supply power to the control circuit 1, and the processor chip in the control circuit 1 can supply power to the subsequent circuit while transmitting the signal to the subsequent circuit, so as to ensure the normal operation of the overall scanning power supply;

[0031] The output end of the D / A converter 2 is electrically connected to the Langmuir probe 9 through the scanning voltage generating circuit 3;

[0032] After receiving the analog scanning parameter signal, the scanning voltage generating circuit 3 generates the required initial voltage according to the parameter value, obtains the scanning voltage after power amplification, and then outputs it to the Langmuir probe 9;

[0033] It should be noted that the scanning voltage generating circuit 3 adopts a PA89 high-voltage power operational amplifier, so that the generated initial voltage range value is: ±600V, and the corresponding scanning voltage range value is: ±500V; the conventional power supply can only output one waveform, and this circuit can output any scanning waveform. In addition, this type of operational amplifier can output a scanning voltage of any waveform as needed, such as a sawtooth wave, a square wave, a sine wave or a pulse wave, and can adjust the bias of the scanning voltage. The characteristics of PA89 are fast speed, low offset rate, and stable output signal, which plays a key role in this design;

[0034] The input end of the sampling circuit 4 is electrically connected to the Langmuir probe 9, and the output end of the sampling circuit 4 is electrically connected to the A / D converter 6 through the signal conditioning circuit 5.

[0035] The potential change on the Langmuir probe 9 is continuously acquired through the sampling circuit 4, and the potential change is a continuous analog signal. Then the signal conditioning circuit 5 proportionally reduces the acquired potential change and sends it to the A / D converter 6 for analog-to-digital conversion of the potential change. This is because the input voltage of the A / D converter 6 is too high, which may cause voltage error, resulting in deviation or distortion of the conversion result, affecting the accuracy and reliability of the A / D converter 6.

[0036] The A / D converter 6 is electrically connected to the input terminal of the control circuit 1;

[0037] The processor chip in the control circuit 1 can perform denoising, filtering, gain adjustment and other processing on the digital potential change signal to optimize the signal quality or meet specific application requirements, which helps to improve the reliability and accuracy of the signal; or decode the digital signal and convert it into readable data, which may involve converting binary data into decimal form, or parsing data according to specific protocols and formats, and the decoded data can be further processed, displayed or transmitted to other systems; or after decoding the signal, perform various data analysis and processing operations according to application requirements, including algorithm calculation, data mining, real-time control, etc.; or send the signal directly back to the host computer 8 for processing;

[0038] It should be noted that the control circuit 1 can send a trigger signal to the D / A converter 2 and the A / D converter 6, that is, before sending the analog scanning parameter signal to the D / A converter 2 and receiving the digital potential change signal sent by the A / D converter 6, the control circuit 1 synchronously sends a trigger signal to the D / A converter 2 and the A / D converter 6. The trigger signal is a timing signal used to trigger the D / A converter 2 and the A / D converter 6 to work. In this way, there can be a certain interval between the D / A converter 2 and the A / D converter 6 sending and receiving signals, so that the control circuit 1 can quickly distinguish the signals to be processed, thereby improving the signal processing efficiency of the control circuit 1, and making the voltage scanning efficiency of the Langmuir probe 9 of the scanning power supply high; in particular, the A / D converter 6 and the D / A converter 2 both use 16-bit high-speed conversion chips;

[0039] Another embodiment of the present invention is:

[0040] On the basis of Example 1, the control circuit 1 includes an FPGA chip 11, a flash memory unit 12, a ROM memory unit 13, a network unit 14 and a power management unit 15; wherein the data pins of the FPGA chip 11 are electrically connected to the flash memory unit 12 and the ROM memory unit 13 respectively, the communication pins of the FPGA chip 11 are electrically connected to the network unit 14, the power pins of the FPGA chip 11 are electrically connected to the power management unit 15, the signal output pins of the FPGA chip 11 are electrically connected to the D / A converter 2, and the signal input pins of the FPGA chip 11 are electrically connected to the A / D converter 6; the network unit 14 is signal-connected to the host computer 8, and the power management unit 15 is electrically connected to the power supply system 7;

[0041] The flash memory unit 12 allows the configuration of the FPGA chip 11 to be updated and modified dynamically, which means that the logical functions of the FPGA chip 11 and the connection mode of the peripherals can be changed by programming without replacing the hardware, thereby providing great advantages for the flexibility and reconfigurability of the system, making the FPGA chip 11 suitable for application scenarios of rapid prototyping and rapid updating;

[0042] Furthermore, the flash memory unit 12 has a large storage capacity and can store complex configuration bit streams, which enables the FPGA chip 11 to support large-scale, high-density logic design and the connection of multiple peripherals to meet the needs of complex applications;

[0043] The ROM memory can be used to store data processed by the FPGA chip 11, and data will not be lost due to power failure, which improves the security of data storage; the ROM memory unit 13 has a fast reading speed, which can achieve fast data access; and the data in the ROM memory unit 13 cannot be written or changed in real time, which is suitable for the scene where only signal data is processed and stored when the Langmuir probe 9 is used;

[0044] The network unit 14 is used to realize long-distance signal transmission between the FPGA chip 11 and the host computer 8, and the power management unit 15 is used to convert the voltage of the power system 7 accordingly and then supply power to the FPGA chip 11;

[0045] In addition, the network unit 14 is connected to the host computer 8 by signal through the Modbus-TCP protocol. The network transmission protocol has the advantages of being simple and easy to use, being able to use the existing Ethernet network infrastructure for communication, and using binary for fast data transmission, and being able to achieve fast and stable signal transmission between the FPGA and the host computer 8; the FPGA chip 11 uses a chip of the XC3S50AN model;

[0046] In addition, the power supply system 7 can convert the external 220V AC high voltage electricity into 24V DC low voltage electricity. The DC power can ensure that the noise and fluctuation generated by the FPGA chip 11 during the power supply process are small, which helps to improve the reliability and performance of the system; the DC power supply can also flexibly provide different voltages and power levels to meet the needs of the FPGA chip 11, making the power supply system more adaptable and scalable; DC power does not need to pass through energy conversion equipment such as transformers and rectifiers, thereby reducing energy loss, which can effectively improve the overall operating efficiency of the control circuit 1; DC power supply can be more easily monitored and controlled through devices such as voltage regulators and current limiters, so that the power supply performance of the FPGA chip 11 can be precisely adjusted and managed according to needs to meet specific system requirements; since DC power does not have the frequency of AC power and related electromagnetic radiation, it can reduce the interference of the circuit to other electronic equipment, and also reduce the potential risk of electric shock.

[0047] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the claims involved.

Claims

1. A plasma density detection scanning power supply, characterized in that: It comprises a control circuit (1), a D / A converter (2), a scanning voltage generating circuit (3), a sampling circuit (4), a signal conditioning circuit (5) and an A / D converter (6); The signal transmission end of the control circuit (1) is electrically connected to a host computer (8), the power input end of the control circuit (1) is electrically connected to a power supply system (7), and the output end of the control circuit (1) is electrically connected to a D / A converter (2); The D / A converter (2) is electrically connected to the Langmuir probe (9) via a scanning voltage generating circuit (3); The input end of the sampling circuit (4) is electrically connected to the Langmuir probe (9), and the output end of the sampling circuit (4) is electrically connected to the A / D converter (6) through the signal conditioning circuit (5); The A / D converter (6) is electrically connected to the input end of the control circuit (1).

2. The plasma density detection scanning power supply according to claim 1, characterized in that: The control circuit (1) comprises an FPGA chip (11), a flash memory unit (12), a ROM memory unit (13), a network unit (14) and a power management unit (15); wherein the data pins of the FPGA chip (11) are electrically connected to the flash memory unit (12) and the ROM memory unit (13), respectively, the communication pins of the FPGA chip (11) are electrically connected to the network unit (14), the power pins of the FPGA chip (11) are electrically connected to the power management unit (15), the signal output pins of the FPGA chip (11) are electrically connected to the D / A converter (2), and the signal input pins of the FPGA chip (11) are electrically connected to the A / D converter (6); the network unit (14) is signal-connected to a host computer (8), and the power management unit (15) is electrically connected to a power supply system (7).

3. The plasma density detection scanning power supply according to claim 2, characterized in that: The network unit (14) is connected to the host computer (8) by signal via the Modbus-TCP protocol.

4. The plasma density detection scanning power supply according to claim 2, characterized in that: The FPGA chip (11) is a chip of the XC3S50AN model.

5. The plasma density detection scanning power supply according to claim 2, characterized in that: The power supply system (7) is capable of converting external 220V AC high voltage electricity into 24V DC low voltage electricity.

6. The plasma density detection scanning power supply according to claim 1, characterized in that: The control circuit (1) is capable of sending a trigger signal to the D / A converter (2) and the A / D converter (6).

7. The plasma density detection scanning power supply according to claim 1, characterized in that: The A / D converter (6) and the D / A converter (2) both use 16-bit high-speed conversion chips.

8. The plasma density detection scanning power supply according to claim 1, characterized in that: The scanning voltage generating circuit (3) is configured as a PA89 high-voltage power operational amplifier.

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