Automatic matcher for radio frequency circuit

Abstract

The invention discloses an automatic matcher for a radio frequency circuit, and belongs to the technical field of radio frequency matchers. The matching network comprises at least one capacitor device and at least one inductor device and is used for impedance matching; the load comprises an equivalent resistor and an equivalent capacitor; the signal detection unit is used for collecting voltage and current of a power supply input signal and phase difference between the voltage and the current, and a detection point A of the signal detection unit is located between the power supply and the matching network. The matching network is matched with the signal detection unit and the control unit, the characteristic and range of load impedance do not need to be known, the final target matching value can be obtained only through two times of impedance operation, the matching time is greatly shortened, and the corresponding speed of the matcher is increased.

Description

Technical Field

[0001] The invention relates to an automatic matcher for a radio frequency circuit, belonging to the technical field of radio frequency matchers. Background Art

[0002] As the core component of RF circuits, RF matching devices are widely used in semiconductors, flat panel displays, LEDs, photovoltaic power generation, medical treatment, scientific research and other fields. The main function of RF matching devices is to ensure that the RF power supply can effectively transfer energy to the load to provide maximum power transmission and system efficiency. Its working principle is to adjust its own parameters (inductance and capacitance) according to the changes in the user's load to achieve the purpose of impedance matching, thereby reducing reflection losses and ensuring that the signal is effectively transmitted to the load end. This matching not only helps to maximize power transmission, but also minimizes reflection losses, prevents interference and echoes, and protects circuit components from damage due to excessive voltage or current. Through the matching circuit, the power supply energy can be maximized and transmitted to the load end, thereby improving the efficiency of the system.

[0003] There are many forms of RF network matching. It can be matched from the power supply end to the load end, from the load end to the power supply end, or from the power supply end and the load end to the middle at the same time. The corresponding signal detection methods are also different. The matching method of most matchers is to know the impedance characteristics and range of the load in advance, and adjust the capacitance and inductance of the matcher accordingly, so that the total impedance of the matcher and the load finally reaches the characteristic impedance of the power supply, 50Ω. The disadvantage of this matching method is that if the load characteristics are not understood, this matching method requires multiple matching adjustments to achieve the best matching effect, which affects the matching response time. Summary of the invention

[0004] To solve the deficiencies of the prior art, an object of the present invention is to provide an automatic matcher for a radio frequency circuit.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: an automatic matcher for a radio frequency circuit, comprising:

[0006] Power supply, used for power supply;

[0007] a matching network, comprising at least one capacitive device and at least one inductive device, for impedance matching; and

[0008] The load includes an equivalent resistor and an equivalent capacitor; and also includes,

[0009] The signal detection unit is used to collect the voltage, current and phase difference of the power input signal.

[0010] The detection point A of the signal detection unit is located between the power supply and the matching network.

[0011] As a preferred solution of the automatic matcher for radio frequency circuit of the present invention, wherein: the signal detection unit comprises:

[0012] A voltage divider circuit for detecting voltage, one end of which is connected to the detection point A and the other end is grounded;

[0013] a low pass filter for detecting phase difference; and,

[0014] A current sensing module for sensing current.

[0015] As a preferred solution of the automatic matcher for radio frequency circuits of the present invention, the current detection module includes:

[0016] A first detection resistor for high voltage terminal detection, connected between detection point A and the load; or,

[0017] A second detection resistor for ground terminal detection, which is connected between the RF ground terminal and the matching device ground terminal; or,

[0018] The current transformer used to output the instantaneous value of the current is connected to the detection point A.

[0019] As a preferred solution of the automatic matcher for radio frequency circuits of the present invention, the matching network is composed of a capacitor and an inductor.

[0020] The capacitive device and the inductive device are connected in series or in parallel to form an L-shaped structure.

[0021] As a preferred solution of the automatic matcher for radio frequency circuits of the present invention, the matching network is composed of a capacitor and two inductors.

[0022] The capacitor and the two inductors are connected to form a T-shaped structure.

[0023] As a preferred solution of the automatic matcher for radio frequency circuits of the present invention, the matching network is composed of two capacitors and two inductors.

[0024] The two capacitors and the two inductors are connected to form a P-type structure.

[0025] As a preferred solution of the automatic matcher for radio frequency circuits described in the present invention, the capacitive device is an adjustable capacitor, the inductive device is an adjustable inductor,

[0026] The values ​​of the capacitive device and the inductive device are matched to the load impedance.

[0027] As a preferred solution of the automatic matcher for radio frequency circuits described in the present invention, it also includes a control unit for controlling the values ​​of the adjustable capacitor and the adjustable inductor to achieve impedance matching with the load.

[0028] As a preferred solution of the automatic matcher for radio frequency circuits described in the present invention, it further includes a storage unit for storing initial values ​​of adjustable capacitors and adjustable inductors in the matching network.

[0029] As a preferred solution of the automatic matcher for radio frequency circuits of the present invention, it also includes an interface unit for communicating with external equipment, which includes:

[0030] A receiving module, used for receiving a control signal from an external device; and

[0031] The sending module is used to send the working status of the matching network.

[0032] The beneficial effects achieved by the present invention are as follows: the matching network provided in the present invention cooperates with the signal detection unit and the control unit, and there is no need to understand the characteristics and range of the load impedance. Only two impedance operations are required to obtain the final target matching value, which greatly reduces the matching time and improves the response speed of the matcher. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the L-type network matching structure of the radio frequency circuit of the present invention;

[0034] Figure 2 The present invention Figure 1 The equivalent circuit and complex impedance structure diagram shown;

[0035] Figure 3 It is a structural schematic diagram of the equivalent transformation of the complex impedance Z2 of the present invention;

[0036] Figure 4 It is a schematic diagram of the structure of adding a capacitor device to the i2 branch of the present invention;

[0037] Figure 5 It is a schematic diagram of the T-type network matching structure of the radio frequency circuit of the present invention;

[0038] Figure 6 It is a schematic diagram of the П-type network matching structure of the radio frequency circuit of the present invention;

[0039] Figure 7 It is a schematic diagram of the composition structure of the present invention;

[0040] The meanings of the reference numerals in the figure are as follows: 100, power supply; 200, matching network; 201, capacitor device; 202, inductor device; 300, load; 301, equivalent resistance; 302, equivalent capacitance; 400, signal detection unit; 401, voltage divider circuit; 402, low-pass filter; 403, current detection module; 403a, first detection resistor; 403b, second detection resistor; 403c, current transformer; 500, control unit; 600, storage unit; 700, interface unit; 701, receiving module; 702, sending module. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0042] like Figures 1 to 7 This embodiment provides an automatic matcher for a radio frequency circuit, which can achieve the effect of improving the response speed of the matcher, and includes a power supply 100, a matching network 200, and a load 300 connected in sequence. Specifically, the power supply 100 is used for power supply; the matching network 200 includes at least one capacitor device 201 and at least one inductor device 202 for impedance matching; the load 300 includes an equivalent resistor 301 and an equivalent capacitor 302.

[0043] The matching network 200 is composed of a capacitor 201 and an inductor 202, which are connected in series or in parallel to form an L-shaped structure. The capacitor 201 is an adjustable capacitor, the inductor 202 is an adjustable inductor, and the values ​​of the capacitor 201 and the inductor 202 match the load 300 impedance.

[0044] The automatic matcher of this embodiment further includes a signal detection unit 400, a control unit 500, a storage unit 600 and an interface unit 700. Figure 7 As shown, the signal detection unit 400 is used to collect the voltage, current and phase difference of the input signal of the power supply 100, and the detection point A of the signal detection unit 400 is located between the power supply 100 and the matching network 200. The signal detection unit 400 includes a voltage divider circuit 401 for detecting voltage, one end of which is connected to the detection point A and the other end is grounded; a low-pass filter 402 for detecting the phase difference; and a current detection module 403 for detecting current.

[0045] In this embodiment, an L-shaped structure in which the matching network 200 is composed of a capacitor 201 and an inductor 202 is used as an example, and the impedance matching process is as follows:

[0046] The first step is to Figure 1The matching device signal input terminal A shown collects the input signal (u, i, φ) of the power supply 100.

[0047] For the detection of voltage u, a voltage divider circuit 401 can be directly connected between point A and ground to output the instantaneous value of the current voltage;

[0048] For the detection of current i, a first detection resistor 403a can be connected between point A and the load end (high voltage end detection requires isolation of high potential), or a second detection resistor 403b can be connected between the RF ground end and the matching device ground end (the problem of potential difference between the RF and matching device ground ends needs to be considered), or a current transformer 403c (considering the frequency problem) can be used to output the instantaneous value of the current;

[0049] For the detection of the phase difference φ between voltage and current: the current voltage u and the current current i are multiplied by an analog multiplier, and the obtained signal is passed through a low-pass filter 402 to separate the DC quantity. The magnitude of the DC voltage component reflects the phase difference φ between the two signals.

[0050] In the second step, the complex impedance Z of the point can be obtained through calculation. The complex impedance Z is the result of the parallel connection of the complex impedances Z1 and Z2 corresponding to the branches i1 and i2. Z1 is the impedance of the capacitor 201, and Z2 is the equivalent result of the series connection of the impedance of the inductor 202 and the impedance of the load 300, as shown in Figure 2 , 3 shown.

[0051] The values ​​of the adjustable capacitance device 201 and the adjustable inductance device 202 are controlled by the control unit 500 to achieve impedance matching with the load 300. The interface unit 700 can communicate with an external device, which includes a receiving module 701 and a sending module 702. The receiving module 701 is used to receive a control signal of an external device, and the sending module 702 is used to send the working state of the matching network 200.

[0052] In the third step, since the initial value of Z1 (corresponding to the capacitor 201) in the matching network 200 is a known quantity, the value of Z2 can be obtained through series and parallel calculation of complex impedances.

[0053] In the fourth step, since the initial value of Z3 (corresponding to the inductor 202) in the matching network 200 is also a known quantity, the value of Z4 can be further obtained based on the series-parallel calculation. Z4 is the complex impedance of the load 300, and the conjugate impedance Z4* of Z4 is used as the final matching target value.

[0054] Step 5: Return to the matching network 200 to adjust the capacitor 201 and the inductor 202 so that the total impedance of the resistor R0 of the power supply 100 and the capacitor and inductor of the matcher reaches the conjugate matching Z4* of Z4.

[0055] Step 6, as an extension of step 5, if the inductor device 202 is a non-adjustable device (fixed value), a capacitor device 201' needs to be introduced to achieve the adjustable impedance of the i2 branch, such as Figure 4 shown.

[0056] Step 7: If you want to achieve a higher matching accuracy, you can repeat the above steps 1 to 5. Theoretically, after more than one operation of the five steps, the accuracy can reach more than 99%.

[0057] It is worth noting that in the above steps 3 and 4, the initial values ​​of Z1 and Z3 are the impedance values ​​(generally capacitive reactance or inductive reactance) automatically saved during the last matching, which are used as backup for the next matching calculation. The initial values ​​of the adjustable capacitor device 201 and the adjustable inductor device 202 in the matching network 200 are stored in the storage unit 600.

[0058] In addition, the load 300 in the above step 4 is not limited to capacitive loads, and inductive loads can also be processed in the same way.

[0059] It is important to note that the matching network 200 mentioned in the above steps is not limited to an L-type matching network 200 consisting of a single capacitor and an inductor, but can be a more complex T-type, П-type, etc. matching network 200. In the calculation process, only the initial values ​​of several devices are added (such as Z1 and Z3). Among them, the T-type matching network 200 consists of a capacitor device 201 and two inductors 202, and the П-type matching network 200 consists of two capacitor devices 201 and two inductors 202. Figure 5 , 6 shown.

[0060] Working principle: Before the matching starts, the values ​​Z1 and Z3 of the capacitor 201 and the inductor 202 in the matching network 200 have been saved in the system as the initial values ​​for this matching. Start the RF power supply 100 and collect signals at the signal detection point A. The voltage u, current i and the phase difference φ between them in the total circuit are collected. At this time, the complex impedance Z of the total circuit can be calculated. The complex impedance Z is the result of the parallel connection of the complex impedances Z1 and Z2 corresponding to the branches i1 and i2. Z1 is the impedance of the capacitor 201, and Z2 is the equivalent result of the series connection of the impedance of the inductor 202 and the impedance of the load 300, as shown in Figure 2 , 3As shown. Since the initial value of Z1 (corresponding to the capacitor device 201) is a known quantity, the value of Z2 can be obtained through the series-parallel calculation of the complex impedance. Since the initial value of Z3 (corresponding to the inductor device 202) is also a known quantity, the value of Z4 can be further obtained according to the series-parallel calculation. Z4 is the complex impedance of the load 300, and the conjugate impedance Z4* of Z4 is used as the final matching target value. Then, return to the matching network 200 to adjust the capacitor device 201 and the inductor device 202 so that the total impedance value of the power supply 100 resistor R0, the capacitance and inductance of the matcher reaches the conjugate matching Z4* of Z4. If the inductor device 202 is a non-adjustable device (fixed value), it is necessary to introduce a capacitor device 201′ to realize the adjustable impedance of the i2 branch, such as Figure 4 Theoretically, after the above steps, the matching accuracy of the matcher can reach more than 99%.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An automatic matcher for a radio frequency circuit, characterized in that: Including connected in sequence, A power supply (100) for supplying power; A matching network (200), comprising at least one capacitive device (201) and at least one inductive device (202), for performing impedance matching; as well as, The load (300) includes an equivalent resistor (301) and an equivalent capacitor (302); and further includes, A signal detection unit (400) is used to collect the voltage and current of a signal input from a power source (100) and the phase difference therebetween. A detection point A of the signal detection unit (400) is located between the power source (100) and the matching network (200).

2. The automatic matching device for radio frequency circuit according to claim 1, characterized in that: The signal detection unit (400) comprises: A voltage divider circuit (401) for detecting voltage, one end of which is connected to a detection point A and the other end is grounded; a low pass filter (402) for detecting a phase difference; and, A current detection module (403) is used to detect current.

3. The automatic matcher for radio frequency circuit according to claim 2, characterized in that: The current detection module (403) comprises: A first detection resistor (403a) for high voltage terminal detection, connected between the detection point A and the load (300); or, A second detection resistor (403b) for ground terminal detection, which is connected between the RF ground terminal and the matching device ground terminal; or, A current transformer (403c) for outputting the instantaneous value of the current is connected to the detection point A.

4. The automatic matcher for radio frequency circuit according to claim 1, characterized in that: The matching network (200) is composed of a capacitor device (201) and an inductor device (202). The capacitive device (201) and the inductive device (202) are connected in series or in parallel to form an L-shaped structure.

5. The automatic matcher for radio frequency circuit according to claim 1, characterized in that: The matching network (200) is composed of a capacitor device (201) and two inductors (202). The capacitor device (201) and the two inductor devices (202) are connected to form a T-shaped structure.

6. The automatic matcher for radio frequency circuit according to claim 1, characterized in that: The matching network (200) is composed of two capacitive devices (201) and two inductive devices (202). The two capacitor devices (201) and the two inductor devices (202) are connected to form a P-type structure.

7. The automatic matcher for radio frequency circuit according to any one of claims 1 to 6, characterized in that: The capacitive device (201) is an adjustable capacitor, the inductive device (202) is an adjustable inductor, The values ​​of the capacitive device (201) and the inductive device (202) are matched to the impedance of the load (300).

8. The automatic matcher for radio frequency circuit according to claim 7, characterized in that: It also includes a control unit (500) for controlling the values ​​of the adjustable capacitance device (201) and the adjustable inductance device (202) to achieve impedance matching with the load (300).

9. The automatic matcher for radio frequency circuit according to claim 7 or 8, characterized in that: It also includes a storage unit (600) for storing initial values ​​of the adjustable capacitance device (201) and the adjustable inductance device (202) in the matching network (200).

10. The automatic matcher for radio frequency circuit according to any one of claims 1 to 6 and 8, characterized in that: Also included is an interface unit (700) for communicating with an external device, which includes, A receiving module (701), used for receiving a control signal from an external device; as well as, The sending module (702) is used to send the working status of the matching network (200).

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