A fast and reliable combustion-supporting circuit for DC magnetron sputtering coating power supply

Abstract

The present invention belongs to the fields of automatic control technology and power electronics technology, and specifically relates to a fast and reliable combustion-supporting circuit for a DC magnetron sputtering coating power supply. By adding a combustion-supporting circuit, the voltage output by the combustion-supporting circuit is superimposed on the voltage output by a high-frequency rectifier bridge of a high-frequency inverter switching power supply to achieve the amplitude of a combustion-supporting ignition voltage. When ignition is successful, the output current of the DC magnetron sputtering power supply exceeds a ignition success judgment threshold, or the output voltage of the DC magnetron sputtering power supply is lower than a main power supply no-load voltage judgment threshold, and the combustion-supporting circuit stops working. At this time, the voltage and current required by the DC magnetron sputtering process are supplied by the main circuit of the DC magnetron sputtering power supply. Once the glow is extinguished, the combustion-supporting circuit starts outputting, and the output voltage of the power supply reaches the amplitude of the combustion-supporting ignition voltage again, thereby ensuring the continuity of the coating process; reducing arc energy and improving coating quality.

Description

Technical Field

[0001] The invention belongs to the field of automatic control technology and power electronics technology, and in particular relates to a fast and reliable combustion-supporting circuit of a DC magnetron sputtering coating power supply. Background Art

[0002] DC magnetron sputtering is an important physical vapor deposition technology, widely used in industrial production and scientific research. DC magnetron sputtering has the advantages of high deposition rate and low substrate temperature. The thin film obtained by sputtering has high purity, good density and good bonding with the substrate. The sputtering process has good repeatability, the film thickness can be controlled, and a thin film with uniform thickness can be obtained on a large area substrate.

[0003] In the DC magnetron sputtering coating process, the operating state of the power supply is divided into two stages: combustion-supporting ignition and sputtering coating. Combustion-supporting ignition stage: The no-load ignition voltage of the DC magnetron sputtering power supply is generally about 800V to 1000V (depending on the specific coating process). In some special application fields, the no-load ignition voltage reaches about 2000V. The ignition current is generally small, about a few amperes (related to factors such as the mechanical and physical design of the target and the gas supply volume). Sputtering coating stage: After the combustion-supporting ignition is successful, the sputtering voltage is generally about 300V to 600V (depending on the specific coating process), and the sputtering current rises from a few amperes to tens of amperes (depending on the specific coating process).

[0004] At present, the normal method to solve the high combustion-supporting ignition voltage in the DC magnetron sputtering coating process is to increase the secondary-to-primary winding turns ratio of the boost main transformer to meet the high no-load ignition voltage requirements of DC magnetron sputtering; In addition, in the actual operation process, the combustion-supporting ignition stage is very short, and the sputtering coating stage is very long. Therefore, it brings unfavorable factors to the main circuit design of the high-frequency inverter switching power supply: the high-frequency boost transformer has a high output voltage, and there is an insulation voltage problem; each bridge arm of the high-frequency rectifier bridge uses multiple fast recovery diodes in series to solve the voltage problem. The more diodes are connected in series, the more difficult it is to solve the voltage balancing problem of the series diodes; When the DC magnetron sputtering power supply outputs the same voltage and current, the larger the secondary-to-primary winding turns ratio of the boost transformer, the larger the primary pulse current, and the inverter full bridge will use a switch tube with a larger rated current level; Especially in the application field where the combustion-supporting ignition DC voltage is particularly high, these problems will increase the material cost of the power supply, reduce reliability, safety and stability, and further affect the stability of the coating process.

[0005] DC magnetron sputtering coating targets are easily poisoned and arced. After the target is poisoned, a higher combustion-supporting and ignition voltage is required. In addition, the atmosphere change in the coating process leads to the need for a higher combustion-supporting and ignition voltage after extinguishing, and it is difficult to achieve combustion-supporting and ignition. For coating process application fields that require a high combustion-supporting and ignition voltage, the target material is in a state of being unable to ignite and discharge normally for a long time or frequently, which will affect the continuity of the coating process. Summary of the invention

[0006] The purpose of the present invention is to provide a fast and reliable combustion-supporting circuit for a DC magnetron sputtering coating power supply to solve the above defects and problems. By adding a combustion-supporting circuit, the voltage output by the combustion-supporting circuit is superimposed on the voltage output by the high-frequency rectifier bridge of the high-frequency inverter switching power supply to achieve the amplitude of the combustion-supporting ignition voltage. When the ignition is successful, the output current of the DC magnetron sputtering power supply exceeds the threshold for judging the success of ignition, or the output voltage of the DC magnetron sputtering power supply is lower than the threshold for judging the no-load voltage of the main power supply, and the combustion-supporting circuit stops working. At this time, the voltage and current required by the DC magnetron sputtering process are supplied by the main circuit of the DC magnetron sputtering power supply (AC three-phase power supply, power frequency rectifier filter circuit, inverter full bridge, high-frequency transformer, high-frequency rectifier bridge and LC filter circuit); once the glow is extinguished, the combustion-supporting circuit starts to output, and the output voltage of the power supply reaches the amplitude of the combustion-supporting ignition voltage again, ensuring the continuity of the coating process; reducing the arc energy and improving the coating quality.

[0007] The technical solution of the present invention is as follows:

[0008] A fast and reliable combustion-supporting circuit for a DC magnetron sputtering coating power supply, comprising an AC three-phase power supply, an industrial frequency rectifier filter circuit, an inverter full-bridge circuit, a high-frequency transformer, a double-tube forward chopper circuit, a high-frequency rectifier bridge, a filter inductor T1 with two isolation windings, a filter capacitor C2, a DSP and CPLD control circuit, a human-computer interaction interface, a Hall current sensor LEM1, a Hall current sensor LEM2, a voltage sampling and linear isolation circuit, a first current sampling circuit, a second current sampling circuit, a first drive isolation circuit, and a second drive isolation circuit;

[0009] The output end of the AC three-phase power supply is connected to an input end of the power frequency rectification and filtering circuit;

[0010] The output end of the power frequency rectification and filtering circuit is connected to an input end of the inverter full-bridge circuit;

[0011] The output end of the inverter full-bridge circuit is connected to the input end of the high-frequency transformer;

[0012] The output end of the high-frequency transformer is connected to the input end of the high-frequency rectifier bridge;

[0013] The output end of the power frequency rectification and filtering circuit is connected to an input end of a dual-tube forward chopper circuit;

[0014] The positive output end of the dual-tube forward chopper circuit is connected to the first winding of the filter inductor T1 with two isolated windings through the Hall current sensor LEM2, corresponding to pins 1 and 2, and the negative output end of the dual-tube forward chopper circuit is connected to pin 1 of the filter inductor T1 with two isolated windings;

[0015] The second winding of the filter inductor T1 with two isolated windings corresponds to pins 3 and 4, and pin 3 is connected to the positive output terminal of the high-frequency rectifier bridge of the DC magnetron sputtering coating power supply;

[0016] The 4th pin of the filter inductor T1 with two isolated windings is connected to one end of the capacitor C2;

[0017] Pins 2 and 4 of the filter inductor T1 with two isolated windings are the same-name terminals;

[0018] The negative output end of the high frequency rectifier bridge of the DC magnetron sputtering coating power supply is connected to the other end of the capacitor C2;

[0019] The filter inductor T1 with two isolated windings has the functions of a filter inductor and a transformer. The voltage across the capacitor C2 is actually the sum of the output voltage of the high-frequency rectifier bridge and the output voltage of the second winding of the filter inductor T1 with two isolated windings.

[0020] One end of the capacitor C2 is connected to one end of the load, and the other end of the capacitor C2 is connected to the other end of the load through the Hall current sensor LEM1;

[0021] The two ends of the capacitor C2 are connected to the input end of the voltage sampling and linear isolation circuit, and the output end of the voltage sampling and linear isolation circuit is connected to an input end of the DSP and CPLD control circuit;

[0022] The output end of the Hall current sensor LEM1 is connected to the input end of the first current sampling circuit, and the output end of the first current sampling circuit is connected to an input end of the DSP and CPLD control circuit;

[0023] The output end of the Hall current sensor LEM2 is connected to the input end of the second current sampling circuit, and the output end of the second current sampling circuit is connected to an input end of the DSP and CPLD control circuit;

[0024] An output end of the DSP and CPLD control circuit is connected to an input end of the second drive isolation circuit, and an output end of the second drive isolation circuit is connected to an input end of the dual-tube forward chopper circuit;

[0025] An output end of the DSP and CPLD control circuit is connected to an input end of the first drive isolation circuit, and an output end of the first drive isolation circuit is connected to an input end of the inverter full-bridge circuit;

[0026] One end of the DSP and CPLD control circuit is connected to one end of the human-computer interaction interface;

[0027] The dual-tube forward chopper circuit is composed of a capacitor C1, two switching tubes, MOSFET or IGBT, and two fast recovery diodes. The switch tube Q1 is above the left bridge arm, the fast recovery diode D2 is below the left bridge arm, the fast recovery diode D1 is above the right bridge arm, and the switch tube Q2 is below the right bridge arm. The cathode of the left bridge arm fast recovery diode D2 is the forward output end of the dual-tube forward chopper circuit, and the anode of the right bridge arm fast recovery diode D1 is the negative output end of the dual-tube forward chopper circuit.

[0028] The magnetic material of the magnetic core of the filter inductor T1 with two isolated windings is a high-frequency soft magnetic material.

[0029] The magnetic material of the core of the filter inductor T1 with two isolated windings is manganese-zinc ferrite.

[0030] The switching frequency range of the switch tube of the double-tube forward chopper circuit is 20kHz-100kHz, and the duty cycle range is 0-40%.

[0031] The DSP and CPLD control circuits are composed of a DSP chip TMS320F28335 and a CPLD chip EPM1270T144C5 with peripheral circuits.

[0032] After the DC magnetron sputtering power supply is turned on and running, if there is no power failure, the DSP and CPLD control circuits gradually and softly open the duty cycle of the drive signal output by the first drive isolation circuit from 0, and the output end of the high-frequency rectifier bridge 105 generates a high-voltage pulse group with an amplitude of V1.

[0033] If the power supply output current is less than the ignition success judgment threshold IREF set in the human-machine interface or the power supply output voltage is greater than the no-load voltage judgment threshold VREF set in the human-machine interface, the DSP and CPLD control circuits gradually and softly open the duty cycle of the drive signal output by the second drive isolation circuit from 0 to 40%, so that the second winding of the filter inductor T1 with two isolation windings generates a high-voltage pulse group with an amplitude of V2, and a no-load voltage of the sum of V1 and V2 will be generated at both ends of the capacitor C2;

[0034] If the load is ignited, the power supply output current is greater than the ignition success judgment threshold IREF set in the human-machine interaction interface, or the power supply output voltage is less than the no-load voltage judgment threshold VREF set in the human-machine interaction interface, the DSP and CPLD control circuits will control the duty cycle of the drive signal output by the second drive isolation circuit to 0, the combustion-supporting circuit stops outputting, and the main power supply outputs power to the load. Once the magnetron target stops discharging, the combustion-supporting circuit will repeat the above process.

[0035] The beneficial effects of the present invention are:

[0036] The invention discloses a fast and reliable combustion-supporting circuit for a DC magnetron sputtering coating power supply. In the case of adding a simple combustion-supporting circuit, the output DC pulse voltage of the combustion-supporting circuit is superimposed on the DC pulse voltage output by the high-frequency rectifier bridge (the voltage required for sputtering coating) to achieve the combustion-supporting ignition voltage required by the DC magnetron sputtering coating process. The power supply can reduce the turns ratio between the secondary side and the primary side of the main power supply high-frequency transformer, reduce the outer dimensions of the magnetic core of the main power supply high-frequency transformer, reduce the number of fast recovery diodes connected in series with the main power supply high-frequency rectifier bridge, reduce the output high-frequency rectifier filter inductance and capacitance, and the switch tube of the high-frequency inverter full bridge can use a switch tube with a lower rated current, thereby improving the no-load voltage while improving the reliability of the main circuit of the power supply and reducing the material cost. The control circuit is simple and reliable, with strong applicability, and is convenient for conventional DC magnetron sputtering power supplies. The installation and modification of the combustion-supporting circuit can overcome the problem that when the target material is poisoned and the arc power supply is shut off or the atmosphere changes and the ignition is extinguished, a higher combustion-supporting and ignition voltage is required, which makes it difficult to ignite the target material. In addition, due to the reduction of the filter inductance and filter capacitance, the energy storage of the inductance and capacitor is reduced. When the target material arcs, the arc energy is also reduced. Moreover, when the target material arcs, the voltage of the power supply output filter capacitor flashes, and the output voltage of the high-frequency rectifier bridge is mainly applied to the first winding of the filter inductor with two isolation windings. The energy is partially transferred to the capacitor of the DC busbar of the power frequency rectifier filter circuit. The arc energy output to the target material is further reduced, thereby improving the coating quality. The combustion-supporting circuit can be applied to conventional DC magnetron sputtering coating occasions or occasions where the amplitude of the magnetron target combustion-supporting and ignition voltage is very high, or other application fields that require a high amplitude of the DC voltage for no-load ignition of the DC power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a block diagram of the hardware system structure of the present invention.

[0038] Figure 2 It is the principle diagram of the dual-tube forward chopper circuit of the present invention.

[0039] In the figure: 101, AC three-phase power supply; 102, power frequency rectifier filter circuit; 103, inverter full-bridge circuit; 104, high-frequency transformer; 105, high-frequency rectifier bridge; 107, voltage sampling and linear isolation circuit; 108, first current sampling circuit; 109, second current sampling circuit; 110, first drive isolation circuit; 111, second drive isolation circuit; 112, DSP and CPLD control circuit; 113, human-computer interaction interface; 115, dual-tube forward chopper circuit. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] See also Figure 1 and Figure 2 The embodiment of the present invention provides a fast and reliable combustion-supporting circuit for a DC magnetron sputtering coating power supply, including: an AC three-phase power supply 101, an industrial frequency rectifier filter circuit 102, an inverter full-bridge circuit 103, a high-frequency transformer 104, a dual-tube forward chopper circuit 115, a high-frequency rectifier bridge 105, a filter inductor T1 with two isolated windings, a filter capacitor C2, a DSP and CPLD control circuit 112, a human-computer interaction interface 113, a Hall current sensor LEM1, a Hall current sensor LEM2, a voltage sampling and linear isolation circuit 107, a first current sampling circuit 108, a second current sampling circuit 109, a first drive isolation circuit 110, and a second drive isolation circuit 111.

[0042] The output end of the AC three-phase power supply 101 is connected to an input end of the power frequency rectification and filtering circuit 102 .

[0043] An output end of the power frequency rectification and filtering circuit 102 is connected to an input end of the inverter full-bridge circuit 103 .

[0044] The output end of the inverter full-bridge circuit 103 is connected to the input end of the high-frequency transformer 104 .

[0045] The output end of the high-frequency transformer 104 is connected to the input end of the high-frequency rectifier bridge 105 .

[0046] The output end of the power frequency rectification and filtering circuit 102 is connected to an input end of the dual-switch forward chopper circuit 115 .

[0047] The positive output end of the dual-tube forward chopper circuit 115 is connected to the 2nd pin of the first winding (corresponding to pins 1 and 2) of the filter inductor T1 with two isolated windings through the Hall current sensor LEM2, and the negative output end of the dual-tube forward chopper circuit 115 is connected to the 1st pin of the filter inductor T1 with two isolated windings.

[0048] The pin 3 of the second winding (corresponding to pins 3 and 4) of the filter inductor T1 with two isolated windings is connected to the positive output terminal of the high-frequency rectifier bridge 105 of the DC magnetron sputtering coating power supply.

[0049] Pin 4 of the filter inductor T1 with two isolated windings is connected to one end of the capacitor C2.

[0050] Pins 2 and 4 of the filter inductor T1 with two isolated windings are the same-name terminals.

[0051] The negative output terminal of the high frequency rectifier bridge 105 of the DC magnetron sputtering coating power supply is connected to the other end of the capacitor C2.

[0052] The filter inductor T1 with two isolated windings has the functions of a filter inductor and a transformer. The voltage across the capacitor C2 is actually the sum of the output voltage of the high-frequency rectifier bridge 105 and the output voltage of the second winding of the filter inductor T1 with two isolated windings.

[0053] One end of the capacitor C2 is connected to one end of the load, and the other end of the capacitor C2 is connected to the other end of the load through the Hall current sensor LEM1.

[0054] The two ends of the capacitor C2 are connected to the input end of the voltage sampling and linear isolation circuit 107, and the output end of the voltage sampling and linear isolation circuit 107 is connected to an input end of the DSP and CPLD control circuit 112 to achieve timely detection of the power supply output voltage.

[0055] The output end of the Hall current sensor LEM1 is connected to the input end of the first current sampling circuit 108, and the output end of the first current sampling circuit 108 is connected to an input end of the DSP and CPLD control circuit 112 to achieve timely detection of the power supply output current, overcurrent protection control and constant current negative feedback control.

[0056] The output end of the Hall current sensor LEM2 is connected to the input end of the second current sampling circuit 109, and the output end of the second current sampling circuit 109 is connected to an input end of the DSP and CPLD control circuit 112 to achieve timely detection of the output current of the dual-tube forward chopper circuit 115, overcurrent protection control and constant current negative feedback control.

[0057] An output end of the DSP and CPLD control circuit 112 is connected to an input end of the second drive isolation circuit 111 , and an output end of the second drive isolation circuit 111 is connected to an input end of the dual-switch forward chopper circuit 115 .

[0058] An output end of the DSP and CPLD control circuit 112 is connected to an input end of the first drive isolation circuit 110 , and an output end of the first drive isolation circuit 110 is connected to an input end of the inverter full-bridge circuit 103 .

[0059] One end of the DSP and CPLD control circuit 112 is connected to one end of the human-machine interaction interface 113 .

[0060] The dual-tube forward chopper circuit 115 is composed of a capacitor C1, two switching tubes (MOSFET or IGBT) and two fast recovery diodes. The switch tube Q1 is located above the left bridge arm, and the fast recovery diode D2 is located below the left bridge arm. The fast recovery diode D1 is located above the right bridge arm, and the switch tube Q2 is located below the right bridge arm. The cathode of the fast recovery diode D2 of the left bridge arm is the forward output terminal of the dual-tube forward chopper circuit 115, and the anode of the fast recovery diode D1 of the right bridge arm is the negative output terminal of the dual-tube forward chopper circuit 115. The switching frequency range of the switch tube is 20kHz to 100kHz, and the duty cycle range is 0 to 40%.

[0061] The magnetic material of the magnetic core of the filter inductor T1 with two isolated windings is manganese-zinc ferrite or other high-frequency soft magnetic materials.

[0062] The DSP and CPLD control circuit 112 is composed of a DSP chip TMS320F28335 and a CPLD chip EPM1270T144C5 with peripheral circuits.

[0063] Control method of combustion-supporting circuit: After the DC magnetron sputtering power supply with combustion-supporting circuit is turned on and running, if there is no fault in the power supply, the DSP and CPLD control circuit 112 gradually turns on the duty cycle of the driving signal output by the first driving isolation circuit 110 from 0, and the output end of the high-frequency rectifier bridge 105 generates a high-voltage pulse group with an amplitude of V1; if the output current of the power supply is less than the ignition success judgment threshold IREF set by the human-machine interface 113 or the output voltage of the power supply is greater than the no-load voltage judgment threshold VREF set by the human-machine interface 113, the DSP and CPLD control circuit 112 gradually turns on the duty cycle of the driving signal output by the second driving isolation circuit 111 from 0 Open to 40%, so that the second winding of the filter inductor T1 with two isolated windings produces a high-voltage pulse group with an amplitude of V2, and a no-load voltage of the sum of V1 and V2 will be generated at both ends of the capacitor C2; if the load is ignited, the power supply output current is greater than the ignition success judgment threshold IREF set by the human-machine interaction interface 113 or the power supply output voltage is less than the no-load voltage judgment threshold VREF set by the human-machine interaction interface 113, the DSP and CPLD control circuit 112 will control the duty cycle of the drive signal output by the second drive isolation circuit 111 to 0, the combustion-supporting circuit stops outputting, and the main power supply outputs power to the load. Once the magnetron target stops discharging, the combustion-supporting circuit will repeat the above process.

Claims

1. A fast and reliable combustion-supporting circuit for a DC magnetron sputtering coating power supply, comprising an AC three-phase power supply, an industrial frequency rectifier filter circuit, an inverter full-bridge circuit, a high-frequency transformer, a double-tube forward chopper circuit, a high-frequency rectifier bridge, a filter inductor T1 with two isolated windings, a capacitor C2, a DSP and CPLD control circuit, a human-computer interaction interface, a Hall current sensor LEM1, a Hall current sensor LEM2, a voltage sampling and linear isolation circuit, a first current sampling circuit, a second current sampling circuit, a first drive isolation circuit, and a second drive isolation circuit; Features: The output end of the AC three-phase power supply is connected to an input end of the power frequency rectification and filtering circuit; The output end of the power frequency rectification and filtering circuit is connected to an input end of the inverter full-bridge circuit; The output end of the inverter full-bridge circuit is connected to the input end of the high-frequency transformer; The output end of the high-frequency transformer is connected to the input end of the high-frequency rectifier bridge; The output end of the power frequency rectification and filtering circuit is connected to an input end of a dual-tube forward chopper circuit; The positive output end of the dual-tube forward chopper circuit is connected to the 2nd foot of the first winding of the filter inductor T1 with two isolated windings through the Hall current sensor LEM2, and the negative output end of the dual-tube forward chopper circuit is connected to the 1st foot of the first winding of the filter inductor T1 with two isolated windings; The 3rd pin of the second winding of the filter inductor T1 with two isolated windings is connected to the positive output terminal of the high-frequency rectifier bridge of the DC magnetron sputtering coating power supply; the 4th pin of the second winding of the filter inductor T1 with two isolated windings is connected to one end of the capacitor C2; Pins 2 and 4 of the filter inductor T1 with two isolated windings are the same-name terminals; The negative output end of the high frequency rectifier bridge of the DC magnetron sputtering coating power supply is connected to the other end of the capacitor C2; The filter inductor T1 with two isolated windings has the functions of a filter inductor and a transformer. The voltage across the capacitor C2 is actually the sum of the output voltage of the high-frequency rectifier bridge and the output voltage of the second winding of the filter inductor T1 with two isolated windings. One end of the capacitor C2 is connected to one end of the load, and the other end of the capacitor C2 is connected to the other end of the load through the Hall current sensor LEM1; The two ends of the capacitor C2 are connected to the input end of the voltage sampling and linear isolation circuit, and the output end of the voltage sampling and linear isolation circuit is connected to the first input end of the DSP and CPLD control circuit; The output end of the Hall current sensor LEM1 is connected to the input end of the first current sampling circuit, and the output end of the first current sampling circuit is connected to the second input end of the DSP and CPLD control circuit; The output end of the Hall current sensor LEM2 is connected to the input end of the second current sampling circuit, and the output end of the second current sampling circuit is connected to the third input end of the DSP and CPLD control circuit; The first output end of the DSP and CPLD control circuit is connected to the input end of the second drive isolation circuit, and the output end of the second drive isolation circuit is connected to a control end of the dual-tube forward chopper circuit; The second output end of the DSP and CPLD control circuit is connected to the input end of the first drive isolation circuit, and the output end of the first drive isolation circuit is connected to a control end of the inverter full-bridge circuit; The control end of the DSP and CPLD control circuit is connected to the output end of the human-computer interaction interface; The dual-tube forward chopper circuit is composed of a capacitor C1, two switch tubes MOSFET or IGBT, and two fast recovery diodes. The switch tube Q1 is located above the left bridge arm, and the fast recovery diode D2 is located below the left bridge arm. The fast recovery diode D1 is located above the right bridge arm, and the switch tube Q2 is located below the right bridge arm. The cathode of the fast recovery diode D2 of the left bridge arm is the forward output end of the dual-tube forward chopper circuit, and the anode of the fast recovery diode D1 of the right bridge arm is the negative output end of the dual-tube forward chopper circuit.

2. A fast and reliable combustion-supporting circuit for DC magnetron sputtering coating power supply as claimed in claim 1, characterized in that: The magnetic material of the magnetic core of the filter inductor T1 with two isolated windings is a high-frequency soft magnetic material.

3. A fast and reliable combustion-supporting circuit for DC magnetron sputtering coating power supply as claimed in claim 2, characterized in that: The magnetic material of the core of the filter inductor T1 with two isolated windings is manganese-zinc ferrite.

4. A fast and reliable combustion-supporting circuit for DC magnetron sputtering coating power supply as claimed in claim 1, characterized in that: The switching frequency range of the switch tube of the double-tube forward chopper circuit is 20kHz-100kHz, and the duty cycle range is 0-40%.

5. A fast and reliable combustion-supporting circuit for DC magnetron sputtering coating power supply as claimed in claim 1, characterized in that: The DSP and CPLD control circuits are composed of a DSP chip TMS320F28335 and a CPLD chip EPM1270T144C5 with peripheral circuits.

6. A fast and reliable combustion-supporting circuit for DC magnetron sputtering coating power supply as claimed in claim 1, characterized in that: After the DC magnetron sputtering coating power supply is turned on and running, and if there is no fault in the DC magnetron sputtering coating power supply, the DSP and CPLD control circuits gradually and softly open the duty cycle of the drive signal output by the first drive isolation circuit from 0, and the output end of the high-frequency rectifier bridge generates a high-voltage pulse group with an amplitude of V1.

7. A fast and reliable combustion-supporting circuit for DC magnetron sputtering coating power supply as claimed in claim 6, characterized in that: If the power supply output current is less than the ignition success judgment threshold IREF set in the human-machine interaction interface or the power supply output voltage is greater than the no-load voltage judgment threshold VREF set in the human-machine interaction interface, the DSP and CPLD control circuit gradually and softly opens the duty cycle of the drive signal output by the second drive isolation circuit from 0 to 40%, so that the second winding of the filter inductor T1 with two isolated windings generates a high-voltage pulse group with an amplitude of V2, and a no-load voltage equal to the sum of V1 and V2 will be generated at both ends of the capacitor C2.

8. A fast and reliable combustion-supporting circuit for DC magnetron sputtering coating power supply as claimed in claim 7, characterized in that: If the load is ignited, the power supply output current is greater than the ignition success judgment threshold IREF set in the human-machine interaction interface or the power supply output voltage is less than the no-load voltage judgment threshold VREF set in the human-machine interaction interface, the DSP and CPLD control circuits will control the duty cycle of the drive signal output by the second drive isolation circuit to 0, and the second winding of the filter inductor T1 with two isolated windings stops outputting, and the high-frequency rectifier bridge outputs power to the load. Once the magnetron target stops discharging, the second winding of the filter inductor T1 with two isolated windings will repeat the output stop process, and the high-frequency rectifier bridge outputs power to the load.

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