Radio frequency power matching circuit and impedance matching method

Abstract

The invention discloses a radio frequency power matching circuit and an impedance matching method, the circuit comprises a detection circuit, a control circuit and an LC adjustable matching network, the detection circuit is used for detecting a forward parameter of a signal input into the LC adjustable matching network and a reverse parameter after the signal is reflected by the LC adjustable matching network; the input end of the control circuit is connected with the output end of the detection circuit, and the control circuit obtains a corresponding matching capacitance value by searching a relation table according to forward parameters and reverse parameters obtained from the detection circuit or adjusts the matching capacitance value to the corresponding matching capacitance value by controlling output impedance and load impedance matching in real time; the control end of the LC adjustable matching network is connected with the output end of the control circuit, a capacitance value is adjusted to a corresponding matching capacitance value under the control of the control circuit, and the output end of the LC adjustable matching network is connected with external equipment. According to the invention, impedance matching adjustment can be simply, conveniently and efficiently realized in radio frequency power current.

Description

Technical Field

[0001] The present invention relates to the technical field of communications and electrical equipment, and in particular to a radio frequency power matching circuit and an impedance matching method. Background Art

[0002] In communication equipment and RF power supply equipment, it is often necessary to adjust the amplifier input, output and inter-stage matching parameters in the equipment, or the RF power supply output impedance range, to achieve impedance matching between the amplifier circuit or the RF power supply and the plasma chamber. The amplifier input, output and inter-stage matching parameters are related to the matching capacitor or inductor at its input or output end, and the impedance matching of the circuit is generally achieved by adjusting the capacitor. The manually adjustable capacitors used in most amplifiers in the prior art have the problem of low flexibility, while the vacuum capacitors have the problems of large size, complex assembly and debugging, high cost and difficulty in application. Therefore, it is urgent to design an RF power matching circuit that can adjust the capacitance value simply and efficiently. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a radio frequency power matching circuit and an impedance matching method in view of the defects in the prior art.

[0004] The technical solution adopted by the present invention to solve the above technical problems is:

[0005] The present invention provides a radio frequency power matching circuit, comprising a detection circuit, a control circuit, and an LC adjustable matching network. The main path of the detection circuit is installed at the input end or the output end of the LC adjustable matching network or at both the input end and the output end, and is used to detect the forward parameters of the signal input to the LC adjustable matching network and the reverse parameters after being reflected by the LC adjustable matching network.

[0006] The input end of the control circuit is connected to the output end of the detection circuit. The control circuit obtains the corresponding matching capacitance value by looking up the relationship table or adjusts the output impedance to the corresponding matching capacitance value by real-time control of the matching of the output impedance and the load impedance according to the forward parameter and the reverse parameter obtained from the detection circuit; the relationship table is pre-stored forward parameters, reverse parameters and matching capacitance values ​​matched under different load impedances;

[0007] The control end of the LC adjustable matching network is connected to the output end of the control circuit. Under the control of the control circuit, the capacitance value is adjusted to the corresponding matching capacitance value, thereby adjusting the impedance of the LC adjustable matching network to make the impedances at both ends of the LC adjustable matching network match. The output end of the LC adjustable matching network is connected to an external device.

[0008] According to the above technical solution, the LC adjustable matching network of the present invention includes at least one switch adjustable capacitor circuit, and at least one inductor component or one capacitor component or one hybrid component; wherein the inductor component is one or more inductors connected in parallel, in series or in series-parallel combination, the capacitor component is one or more capacitors connected in parallel, in series or in series-parallel combination, and the hybrid component is one or more groups of inductors and capacitors connected in parallel, in series or in series-parallel combination. The capacitor is a high-Q ceramic capacitor, a metal film capacitor or a metal electrode capacitor.

[0009] According to the above technical solution, the LC adjustable matching network of the present invention is a low-pass matching circuit, a high-pass matching circuit or a band-pass matching circuit. The circuit structure of the LC adjustable matching network is an L-type matching network, a π-type matching network or a T-type matching network.

[0010] According to the above technical solution, the switch adjustable capacitor circuit of the present invention comprises an array composed of switch capacitor devices and a switch control port, and the switch control port is connected to each switch capacitor device.

[0011] According to the above technical solution, the switch capacitor devices are connected in parallel, in series or in a combination of series and parallel to form an array.

[0012] According to the above technical solution, the switch capacitor device includes a switch and at least one capacitor component, the capacitor component and the switch are connected in series or in parallel. The capacitor component is one or more capacitors connected in parallel, in series or in combination of series and parallel.

[0013] According to the above technical scheme, the capacitor of the present invention is a high-Q ceramic capacitor, a metal film capacitor or a metal electrode capacitor; the switch is a mechanical switch or an electronic switch, wherein the electronic switch is a radio frequency power switch, a Pin tube switch, a relay switch or a MEMS switch.

[0014] According to the above technical solution, the switch adjustable capacitor circuit of the present invention is replaced by a switch adjustable inductor circuit or a switch adjustable capacitor-inductor hybrid circuit, that is, the capacitor component contained in the switch capacitor device in the switch adjustable capacitor circuit is replaced by an inductor component or a hybrid component. The inductor component is one or more inductors connected in parallel, in series, or in a combination of series and parallel, and the hybrid component is one or more groups of inductors and capacitors connected in parallel, in series, or in a combination of series and parallel.

[0015] The present invention provides a control method for radio frequency power impedance matching, comprising the following steps:

[0016] Acquire an input signal and detect a forward parameter and a reverse parameter of the input signal;

[0017] According to the detected forward parameters and reverse parameters, the matching capacitance value is searched from the relationship table, and the capacitance value is adjusted to the matching capacitance value; or the output impedance is calculated according to the detected forward parameters and reverse parameters, and the output impedance is controlled in real time to match the load impedance to adjust to the matching capacitance value; the relationship table is pre-stored forward parameters, reverse parameters and matching capacitance values ​​matched under different load impedances.

[0018] According to the above technical solution, the method for calculating the output impedance includes the steps of:

[0019] According to the detected forward parameters and reverse parameters, the current value and voltage value of the input signal are obtained;

[0020] The vector phase difference is calculated according to the current value and the voltage value, and the input impedance or the output impedance is calculated according to the current value, the voltage value and the vector phase difference. The calculation method is: Among them, U is the voltage value, I is the current value, θ is the vector phase difference, and is the input impedance or output impedance;

[0021] The input impedance or output impedance is calculated based on the input impedance or output impedance and the parameters of the circuit through which the input signal passes.

[0022] The beneficial effects of the present invention are as follows: the RF power matching circuit in the present invention includes structures such as a detection circuit, a control circuit and an LC adjustable matching network. By pre-storing a correspondence table of forward parameters, reverse parameters and matching capacitance values ​​under different load impedances, when a signal is input, the forward parameters and reverse parameters of the input signal are detected, and the matching capacitance value in the correspondence table can be directly called to adjust the impedance matching, or the output impedance and the load impedance can be matched in real time, making the impedance matching adjustment simpler and more efficient.

[0023] Furthermore, the LC adjustable matching network in the present invention can be a low-pass matching circuit, a high-pass matching circuit or a band-pass matching circuit, so that the adjustable input signal has a wider frequency range;

[0024] Furthermore, the present invention sets a switch control port in the switch adjustable capacitor circuit, and directly adjusts the switch state in the switch adjustable capacitor circuit by receiving a control signal, thereby improving the response speed of the switch and making the impedance matching adjustment faster.

[0025] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A circuit structure diagram of a radio frequency power matching circuit according to an embodiment of the present invention;

[0027] Figure 2A circuit structure of an LC adjustable matching network in a radio frequency power matching circuit according to an embodiment of the present invention;

[0028] Figure 3 Another circuit structure of an LC adjustable matching network in a radio frequency power matching circuit according to an embodiment of the present invention;

[0029] Figure 4 A third circuit structure of the LC adjustable matching network in the radio frequency power matching circuit according to an embodiment of the present invention;

[0030] Figure 5 This is a fourth circuit structure of the LC adjustable matching network in the radio frequency power matching circuit according to an embodiment of the present invention;

[0031] Figure 6 A circuit structure diagram of a switched capacitor device in an LC adjustable matching network in a radio frequency power matching circuit according to an embodiment of the present invention;

[0032] Figure 7 A circuit structure diagram corresponding to a switched capacitor device array in an LC adjustable matching network in a radio frequency power matching circuit according to an embodiment of the present invention;

[0033] Figure 8 Another circuit structure diagram corresponding to the switched capacitor device array in the LC adjustable matching network in the radio frequency power matching circuit according to an embodiment of the present invention;

[0034] Fig. 9 This is a third circuit structure diagram corresponding to the switched capacitor device array in the LC adjustable matching network in the radio frequency power matching circuit according to an embodiment of the present invention.

[0035] Fig.10 FIG. 4 is another circuit structure diagram of a radio frequency power matching circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] The radio frequency power matching circuit of the present invention mainly completes the precise adjustment of the corresponding circuit parameters by detecting the corresponding relationship between the characteristic parameters in the circuit and the circuit parameters to be adjusted, thereby realizing impedance matching of the radio frequency power circuit.

[0038] Example 1

[0039] This embodiment provides a radio frequency power matching circuit, such as Figure 1As shown, the RF power matching circuit includes a detection circuit, a control circuit and an LC adjustable matching network, wherein the main path of the detection circuit is installed at the input end of the LC adjustable matching network, the input end of the control circuit is connected to the output end of the detection circuit, the control end of the LC adjustable matching network is connected to the output end of the control circuit, and the output end of the LC adjustable matching network is connected to an external device.

[0040] Each structure in the circuit of the present invention can adopt discrete devices, which can make the entire layout design compact, thereby fully utilizing the design space of the product.

[0041] Specifically, the detection circuit includes a forward coupling circuit, a reverse coupling circuit, and an analog-to-digital conversion circuit. The forward coupling circuit is used to couple and extract the forward signal input into the RF power matching circuit, obtain the forward parameters, and output the forward signal to the analog-to-digital conversion circuit; the reverse coupling circuit is used to couple and extract the reverse signal of the RF power matching circuit, obtain the forward parameters, and output the reverse signal to the analog-to-digital conversion circuit. The coupling circuit uses any combination of microstrips, capacitors, screws, coils, copper rings, metal cavities and other devices to achieve coupling. The analog-to-digital conversion circuit converts the analog signal into a digital signal and inputs it into the control circuit, and controls the switch through the logic circuit.

[0042] Specifically, the structure of the LC adjustable matching network includes at least one switch adjustable capacitor circuit, and at least one inductor component or a capacitor component or a hybrid component; wherein the inductor component is one or more inductors connected in parallel, in series or in a combination of series and parallel, the capacitor component is one or more capacitors connected in parallel, in series or in a combination of series and parallel, and the hybrid component is one or more groups of inductors and capacitors connected in parallel, in series or in a combination of series and parallel; the LC adjustable matching network can be an L-type matching network, a π-type matching network or a T-type matching network; the LC adjustable matching network can be a low-pass matching circuit, a high-pass matching circuit or a band-pass matching circuit.

[0043] like Figure 2 As shown, the structure of the LC adjustable matching network in one embodiment is composed of a parallel capacitor CL, a series capacitor CT and an inductor connected in series in sequence;

[0044] like Figure 3 As shown, the structure of the LC adjustable matching network of another embodiment is composed of an inductor, a parallel capacitor CL and a series capacitor CT connected in series in sequence;

[0045] like Figure 4 As shown, the structure of the LC adjustable matching network of the third embodiment is composed of a parallel capacitor CL, an inductor and a parallel capacitor CT connected in series in sequence;

[0046] like Figure 5As shown, the structure of the LC adjustable matching network of the fourth embodiment is composed of an inductor, a parallel capacitor CL and another inductor connected in series in sequence.

[0047] Specifically, the switch adjustable capacitor circuit is an array composed of a plurality of switch capacitor devices, which includes two electrode ports and a switch control port, wherein the switch control port is connected to each switch capacitor device and is used to provide power to the switch in the switch adjustable capacitor circuit and to control the switch state;

[0048] In the array, multiple switched capacitor devices can be connected in parallel, in series, or in a combination of partial series and partial parallel connection. No matter how they are connected, the purpose is to be able to control the switches so that the capacitance value can be adjusted as needed.

[0049] Figure 7 The structure of a switch adjustable capacitor circuit of an embodiment, in which multiple switch capacitor devices are connected in parallel. Specifically, switch capacitor device 101, switch capacitor device 102, ..., switch capacitor device 10n and other n switch capacitor devices are connected in parallel. Among them, one end of the n switch capacitor devices is connected to the electrode port A, and the other end is connected to another electrode port B of the switch adjustable capacitor circuit. Each control end corresponding to the n switch capacitor devices is respectively connected to the control circuit, and the control of the capacitance value of the switch adjustable capacitor circuit is achieved by respectively controlling the conduction state of the switch K1 to the switch Kn in each switch capacitor device.

[0050] like Figure 8 The structure of the switch adjustable capacitor circuit of another embodiment is shown, in which two switch capacitor devices are connected in series as a group, and n groups of switch capacitor devices are connected in parallel. Among them, one end of the n groups of switch capacitor devices is connected to the electrode port A, and the other end is connected to another electrode port B of the switch adjustable capacitor circuit. Each control end corresponding to the 2n switch capacitor devices is respectively connected to the control circuit, and the control of the capacitance value of the switch adjustable capacitor circuit is achieved by respectively controlling the conduction state of the switch K11 to the switch K2n in each switch capacitor device. In other embodiments, the number of a group of switch capacitor devices can be multiple.

[0051] like Fig. 9The structure of the switch adjustable capacitor circuit of the third embodiment is shown. In this embodiment, n switch capacitor devices are connected in parallel as a group, and two groups of switch capacitor devices are connected in series. Among them, one end of the two groups of switch capacitor devices is connected to the electrode port A, and the other end is connected to the other electrode port B of the switch adjustable capacitor circuit. Each control end corresponding to the 2n switch capacitor devices is respectively connected to the control circuit, and the control of the capacitance value of the switch adjustable capacitor circuit is achieved by respectively controlling the conduction state of the switch K11 to the switch K2n in each switch capacitor device. In other embodiments, there can be multiple groups of switch capacitor device groups connected in series.

[0052] The switch capacitor device may include a switch and at least one capacitor component, wherein the capacitor component and the switch are connected in series or in parallel. The capacitor may be a high-Q ceramic capacitor, a metal film capacitor or a metal electrode capacitor, and the switch may be a mechanical switch or an electronic switch, wherein the electronic switch may be a radio frequency power switch, a pin switch, a relay switch or a MEMS switch.

[0053] The switch adjustable capacitor circuit may also be replaced by a switch adjustable inductor circuit or a switch adjustable capacitor-inductor hybrid circuit, that is, the capacitor component included in the switch capacitor device in the switch adjustable capacitor circuit is replaced by an inductor component or a hybrid component.

[0054] Specifically, Figure 6 As shown, one port A of the capacitor C1 is a port of the switched capacitor device, the other end of the capacitor C1 is connected to a port of the switch K1, the other port B of the switch K1 is another port of the switched capacitor device, and the control port of the switch K1 is the control terminal T of the switched capacitor device. When K1 is turned on, the capacitor C1 is in the on state, and the capacitance of the switched capacitor device is consistent with the capacitance of the capacitor C1.

[0055] Specifically, the capacitance values ​​in the switched capacitor device can be the same or different. By adjusting the switch state in the switched capacitor device, the capacitance value of the switched adjustable capacitor circuit can be adjusted in steps continuously or discontinuously. The minimum accuracy of multiple capacitance values ​​in the switched adjustable capacitor circuit is 0.1PF.

[0056] Example 2

[0057] The present embodiment provides a chip integrated with the switch adjustable capacitor circuit in Embodiment 1, wherein the peripheral interface of the chip comprises two electrode ports and a control port of the switch adjustable capacitor circuit, wherein the two electrode ports are respectively connected to the two ends of the capacitor in the switch adjustable capacitor circuit, and the two electrode ports can be connected in series or in parallel in the circuit according to application requirements, and the control port is connected to an external control circuit, and the switch in the switch adjustable capacitor circuit is controlled by the external control circuit, thereby realizing the adjustment of the capacitance of the present chip, and the chip in the present embodiment can be connected to a variety of circuits to adjust impedance matching.

[0058] Example 3

[0059] This embodiment provides a control method for radio frequency power impedance matching, which can be implemented in the radio frequency power matching circuit of embodiment 1. The specific steps are as follows:

[0060] S1, input a signal and detect the forward parameter of the LC adjustable matching network and the reverse parameter after reflection, wherein the input signal may be a radio frequency signal or a radio frequency power current, and the forward parameter and the reverse parameter may be the value of frequency, current, voltage or power;

[0061] S2. According to the forward parameters and reverse parameters detected in S1, the matching capacitance value is searched from the stored relationship table. The relationship table can be stored in the control circuit or the detection circuit, and contains the matching forward parameters, reverse parameters and matching capacitance values ​​under different load impedances, and the analog signal of the matching capacitance value is converted into a digital signal and sent to the control circuit. The control circuit uses a logic circuit to control the switch in the switch adjustable capacitance circuit through the switch control port, and adjusts the capacitance value to the matching capacitance value obtained by searching the relationship table in S2, thereby achieving impedance matching of the circuit; the output impedance can also be calculated according to the forward parameters and reverse parameters detected in S1, and the capacitance value of the LC adjustable matching network is adjusted in real time through the control circuit to achieve output impedance matching with load impedance.

[0062] Example 4

[0063] This embodiment provides another RF power matching circuit. The structure of the RF power matching circuit of this embodiment is basically the same as that of the RF power matching circuit described in Embodiment 1. The difference is that the main path of the detection circuit of the RF power matching circuit of this embodiment is installed at the output end of the LC adjustable matching network. Fig.10 shown.

[0064] This embodiment also provides a control method for RF power impedance matching, which can be implemented in the above-mentioned RF power matching circuit. The steps of the control method for RF power impedance matching in this embodiment are basically the same as the steps of the control method for RF power impedance matching described in Example 3, with the difference that, in step S1, a signal is input and the forward parameters of the output end of the LC adjustable matching network and the reverse parameters after reflection at the output end are detected.

[0065] Example 5

[0066] This embodiment provides a communication or radio frequency power supply device, the structure of which includes the radio frequency power matching circuit in Embodiment 1 or Embodiment 4.

[0067] The radio frequency power matching circuit of the present invention can be applied to radio frequency power supply equipment, and can also be applied between the input end and the output end of an amplifier circuit to adjust the impedance matching between radio frequency power supplies or amplifier circuit stages. By storing a corresponding relationship table of forward parameters, reverse parameters and matching capacitance values ​​matched under different impedances, in actual application, the forward parameters and reverse parameters of the input signal are detected, and the corresponding capacitance value can be found through the corresponding relationship table, and then the adjustable capacitance in the circuit is adjusted to the corresponding capacitance value, and the output impedance can be controlled to match the load impedance in real time, so that the impedance matching adjustment between radio frequency power supplies or amplifier circuit stages can be quickly realized.

[0068] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A radio frequency power matching circuit, characterized in that: It includes a detection circuit, a control circuit and an LC adjustable matching network; wherein: The main path of the detection circuit is installed at the input end or the output end of the LC adjustable matching network or at both the input end and the output end, and is used to detect the forward parameters and reverse parameters of the signal at the input end or the output end or at both the input end and the output end of the LC adjustable matching network; The input end of the control circuit is connected to the output end of the detection circuit. The control circuit obtains the corresponding matching capacitance value by looking up the relationship table or adjusts the output impedance to the corresponding matching capacitance value by real-time control of the matching of the output impedance and the load impedance according to the forward parameter and the reverse parameter obtained from the detection circuit; the relationship table is pre-stored forward parameters, reverse parameters and matching capacitance values ​​matched under different load impedances; The control end of the LC adjustable matching network is connected to the output end of the control circuit, and the capacitance value is adjusted to the corresponding matching capacitance value under the control of the control circuit. The output end of the LC adjustable matching network is connected to an external device.

2. The radio frequency power matching circuit according to claim 1, characterized in that: The LC adjustable matching network includes at least one switch adjustable capacitor circuit, and at least one inductor component or one capacitor component or one hybrid component; wherein the inductor component is one or more inductors connected in parallel, in series or in a combination of series and parallel, the capacitor component is one or more capacitors connected in parallel, in series or in a combination of series and parallel, and the hybrid component is one or more groups of inductors and capacitors connected in parallel, in series or in a combination of series and parallel.

3. The radio frequency power matching circuit according to claim 1, characterized in that: The LC adjustable matching network is a low-pass matching circuit, a high-pass matching circuit or a band-pass matching circuit; The circuit structure of the LC adjustable matching network is an L-type matching network, a π-type matching network or a T-type matching network.

4. The radio frequency power matching circuit according to claim 2, characterized in that: The switch adjustable capacitance circuit comprises an array of switch capacitor devices and a switch control port, wherein the switch control port is connected to each switch capacitor device.

5. The radio frequency power matching circuit according to claim 4, characterized in that: The switch capacitor devices are connected in parallel, in series or in a combination of series and parallel to form an array.

6. The radio frequency power matching circuit according to claim 5, characterized in that: The switched capacitor device comprises a switch and at least one capacitor component, wherein the capacitor component and the switch are connected in series or in parallel.

7. The radio frequency power matching circuit according to claim 6, characterized in that: The capacitor is a high-Q ceramic capacitor, a metal film capacitor or a metal electrode capacitor; the switch is a mechanical switch or an electronic switch, wherein the electronic switch is a radio frequency power switch, a Pin tube switch, a relay switch or a MEMS switch.

8. The radio frequency power matching circuit according to claim 2, characterized in that: The switch-adjustable capacitor circuit is replaced by a switch-adjustable inductor circuit or a switch-adjustable capacitor-inductor hybrid circuit.

9. A control method for radio frequency power impedance matching, characterized in that: The following steps are involved: Acquire an input signal and detect a forward parameter and a reverse parameter of the input signal; According to the detected forward parameters and reverse parameters, the matching capacitance value is searched from the relationship table, and the capacitance value is adjusted to the matching capacitance value; or the output impedance is calculated according to the detected forward parameters and reverse parameters, and the output impedance is controlled in real time to match the load impedance to adjust to the matching capacitance value; the relationship table is pre-stored forward parameters, reverse parameters and matching capacitance values ​​matched under different load impedances.

10. The control method for radio frequency power impedance matching according to claim 9, characterized in that: The method for calculating the output impedance includes: According to the detected forward parameters and reverse parameters, the current value and voltage value of the input signal are obtained; The vector phase difference is calculated according to the current value and the voltage value, and the input impedance or the output impedance is calculated according to the current value, the voltage value and the vector phase difference. The calculation method is: Where U is the voltage value, I is the current value, θ is the vector phase difference, and Z is the input impedance or output impedance; The input impedance or output impedance is calculated based on the input impedance or output impedance and the parameters of the circuit through which the input signal passes.

Images