Balanced power amplifier topology circuit for radio-frequency power source, and control method for balanced power amplifier topology circuit

Abstract

The present application belongs to the technical field of radio-frequency high-power amplifiers, and relates to a balanced power amplifier topology circuit for a radio-frequency power source, and a control method for a balanced power amplifier topology circuit, which solve the problem of an existing balanced power amplifier topology mode having a high cost and poor precision. In the balanced power amplifier topology circuit, an input end of a first power divider is connected to an output end of a power source; one output end of the first power divider is connected to an input end of a 90° phase shifter, and an output end of the 90° phase shifter is connected to an input end of a second power divider; the second power divider is sequentially connected to a first matching circuit and a first power combiner; the other output end of the first power divider is directly connected to an input end of a third power divider; the third power divider is sequentially connected to a second matching circuit and a second power combiner; an output end of the first power combiner and an output end of the second power combiner are respectively connected to a path end and a coupling end of a coupler; and a common-source end of the coupler is connected to a load.

Description

A balanced power amplifier topology circuit of a radio frequency power supply and a control method thereof Technical Field

[0001] The present application relates to the technical field of radio frequency high-power amplifiers, and in particular to a balanced power amplifier topology circuit of a radio frequency power supply and a control method thereof. Background Art

[0002] RF power amplifiers are widely used not only in wireless communications equipment but also as RF power supplies in plasma systems. In RF power-plasma systems, variations in RF power affect the plasma's equivalent impedance, and changes in plasma impedance also affect the RF power. When the cavity's gas impedance reaches the RF power amplifier's maximum power impedance, the unbalanced amplifier experiences a momentary power overshoot, potentially damaging the circuit. In pulsed applications, sudden changes in plasma impedance can cause RF power overshoots.

[0003] When the load impedance reaches the maximum power impedance point of the RF power amplifier, reflected power is generated. Excessive reflected power can cause power supply energy overshoot, even damaging circuits and equipment. Therefore, it is important to find appropriate methods to suppress energy overshoot.

[0004] There are two main methods for reducing reflected power to suppress energy overshoot:

[0005] (1) Through an LC matching circuit (matcher): Add an inductor L and a capacitor C network between the load and the power supply to make the load impedance conjugate with the RF power supply output impedance. These types include L-type, T-type, and π-type. Impedance network matching is divided into manual adjustment and automatic adjustment. The impedance network size is mainly adjusted by adjusting the size of the capacitor.

[0006] (2) Software (PID algorithm) control circuit: When the output power at the output end exceeds the threshold, the input power of the power amplifier is reduced in time.

[0007] Existing methods for suppressing energy overshoot have the following disadvantages:

[0008] (1) There are many discrete components in the circuit, which results in high cost;

[0009] (2) When the load changes rapidly, there will still be a certain energy overshoot problem due to control delay and accuracy issues.

[0010] Summary of the Invention

[0011] In view of the above analysis, the embodiments of the present application aim to provide a balanced power amplifier topology circuit of a radio frequency power supply and a control method thereof, so as to solve the problems of high cost and poor precision existing in the existing balanced power amplifier topology.

[0012] On the one hand, the present application discloses a balanced power amplifier topology circuit of a radio frequency power supply, wherein the balanced power amplifier topology circuit includes a first power divider, a 90° phase shifter, a second power divider, a third power divider, a first matching circuit, a second matching circuit, a first power combiner, a second power combiner, and a coupler; wherein,

[0013] The input end of the first power divider is connected to the output end of the power supply; one output end of the first power divider is connected to the input end of the 90° phase shifter, and the output end of the 90° phase shifter is connected to the input end of the second power divider; the output end of the second power divider is connected to the input end of the first matching circuit, the output end of the first matching circuit is connected to the input end of the first power combiner, and the output end of the first power combiner is connected to the path end of the coupler;

[0014] The other output end of the first power divider is directly connected to the input end of the third power divider; the output end of the third power divider is connected to the input end of the second matching circuit, the output end of the second matching circuit is connected to the input end of the second power combiner, and the output end of the second power combiner is connected to the coupling end of the coupler; the common source end of the coupler is connected to the load;

[0015] The first matching circuit and the second matching circuit each include N reference matching circuits; N≥2, and N is an integer; the reference matching circuit includes an input matching circuit, a radio frequency power amplifier, and an output matching circuit connected in sequence.

[0016] Based on the above solution, this application also makes the following improvements:

[0017] Furthermore, the second power divider and the third power divider are both 1-to-N power dividers; the first power combiner and the second power combiner are both N-to-1 power combiners;

[0018] Each output end of the second power divider and the third power divider is connected to the input end of a reference matching circuit respectively; each input end of the first power combiner and the second power combiner is connected to the output end of a reference matching circuit respectively.

[0019] Furthermore, the reference matching circuit further includes a DC isolation module connected after the output matching circuit;

[0020] The input end of the input matching circuit serves as the input end of the reference matching circuit, and the output end of the DC isolation module serves as the output end of the reference matching circuit.

[0021] Furthermore, the input impedances of the input ends of the second power divider and the third power divider are both characteristic impedances of the power supply; the output impedances of the N output ends of the second power divider and the third power divider are equal, and the equivalent impedance of the output impedances of the N output ends is the characteristic impedance of the power supply;

[0022] The output impedances of the output ends of the first power combiner and the second power combiner are both the characteristic impedances of the power supply; the input impedances of the N input ends of the first power combiner and the second power combiner are equal, and the equivalent impedance of the input impedances of the N input ends is the characteristic impedance of the power supply.

[0023] Furthermore, the input matching circuit is used to transform the output impedance of one output end of the second power divider or the third power divider to the input impedance of the RF power amplifier, so that the output impedance of the output end of the second power divider or the third power divider is conjugate matched with the input impedance of the RF power amplifier after being transformed by the input matching circuit.

[0024] Furthermore, the output matching circuit is used to transform the output impedance of the RF power amplifier to the input impedance of one input end of the first power combiner or the second power combiner, so that the output impedance of the RF power amplifier is conjugate matched with the input impedance of one input end of the first power combiner or the second power combiner after being transformed by the output matching circuit.

[0025] Furthermore, when reflected power is generated at the path end of the coupler, the reflected power is eliminated by using the coupler, the first power combiner and the second power combiner.

[0026] Furthermore, the balanced power amplifier topology circuit further includes a control module;

[0027] The control module is used to measure and process the actual input power of the load when the common source end of the coupler does not generate reflected power, obtain a power supply output power control signal; and adjust the output power of the power supply based on the power supply output power control signal.

[0028] On the other hand, the present application also discloses a method for controlling a balanced power amplifier topology circuit of a radio frequency power supply, the method comprising:

[0029] The output signal of the power supply is processed by the first power divider and the 90° phase shifter so that the voltages input to the second power divider and the third power divider have the same amplitude and a 90° phase difference;

[0030] The voltage input to the second power divider is decomposed into N paths with the same amplitude and phase, matched and amplified by the first matching circuit, and combined into one path of power by the first power combiner before inputting into the path end of the coupler;

[0031] The voltage input to the third power divider is decomposed into N paths with the same amplitude and phase, matched and amplified by the second matching circuit, and combined into one path of power by the second power combiner before inputting into the coupling end of the coupler;

[0032] If the common source end of the coupler does not generate reflected power, measuring and processing the actual input power of the load to obtain an output power control signal of the power supply, and adjusting the output power of the power supply based on the output power control signal of the power supply;

[0033] If the common source end of the coupler generates reflected power, the coupler and the first power combiner and the second power combiner are used to eliminate the reflected power.

[0034] Based on the above solution, this application also makes the following improvements:

[0035] Furthermore, the eliminating the reflected power by using a coupler and a first power combiner and a second power combiner includes:

[0036] The reflected voltage is input from the common source end of the coupler, and then the voltages with the same amplitude and 90° phase difference are output from the path end and coupling end of the coupler respectively.

[0037] The voltages outputted from the channel end and the coupling end of the coupler are blocked by the first power combiner and the second power combiner, respectively. The amplitudes of the voltages outputted from the channel end and the coupling end of the coupler change by multiples of the reflection coefficients of the first power combiner and the second power combiner, respectively, while the phases remain unchanged.

[0038] The voltages blocked and reflected by the first power combiner and the second power combiner are input from the path end and the coupling end of the coupler respectively, and the common source end of the coupler outputs voltages with opposite phases and equal amplitudes, and the reflected power is eliminated.

[0039] Compared with the prior art, this application can achieve at least one of the following beneficial effects:

[0040] In summary, the balanced power amplifier topology circuit of the RF power supply provided in this application adds a balanced power amplifier topology circuit between the power supply and the load, so that the generated reflected power does not affect the power supply. At the same time, PID feedback regulation is added. The balanced power amplifier and control module jointly ensure that the output of the power supply is stable within a predetermined range and can effectively suppress energy overshoot. The beneficial effects of this embodiment are specifically described as follows:

[0041] (1) The circuit structure of the balanced power amplifier topology circuit is simple, and the devices used in the circuit are all commonly used devices in this field. It is easy to implement and does not require a complex circuit network or the calculation of too many parameters.

[0042] (2) Two power combiners and a coupler are used to solve the energy overshoot problem caused by reflected power. This solution is not affected by load changes and does not need to consider control accuracy and delay issues, making it more stable.

[0043] (3) Balanced amplifiers have good input and output matching characteristics and can amplify power at the same time.

[0044] (4) A simple PID control module automatically adjusts the output power of the power supply to ensure that the load receives the predetermined input power, while preventing energy overshoot from occurring during the process of the load receiving the predetermined input power.

[0045] (5) Compared with 90° or other couplers, the 45° coupler proposed in this application can ensure that the energy output from the two ports is the same, better reduce power loss during transmission, and better achieve energy overshoot suppression function.

[0046] Since the control method in the present application has the same principle as that of the above-mentioned balanced power amplifier topology circuit, the control method in the present application also has the corresponding technical effects of the above-mentioned balanced power amplifier topology circuit.

[0047] In this application, the above-mentioned technical solutions can be combined with each other to achieve more preferred combination solutions. Other features and advantages of this application will be described in the subsequent description, and some advantages will become apparent from the description or be understood by practicing this application. The objectives and other advantages of this application can be achieved and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present application. Throughout the drawings, the same reference symbols denote the same components.

[0049] FIG1 is a schematic structural diagram of a balanced power amplifier topology circuit of a radio frequency power supply provided in Example 1 of the present application;

[0050] FIG2 is a schematic structural diagram of a balanced power amplifier topology circuit of a radio frequency power supply when N is 3, provided in Example 1 of the present application;

[0051] FIG3 is a circuit diagram of a Wilkinson one-to-two power divider provided in Example 1 of the present application;

[0052] FIG4 is a circuit diagram of a 90° phase shifter provided in Example 1 of the present application;

[0053] FIG5 is a circuit diagram of a Wilkinson one-to-three power divider provided in Example 1 of the present application;

[0054] FIG6 is a circuit diagram of a radio frequency power amplifier circuit provided in Example 1 of the present application;

[0055] FIG7 is a circuit diagram of an output matching circuit provided in Example 1 of the present application;

[0056] FIG8 is a circuit diagram of a Wilkinson three-in-one power combiner provided in Example 1 of the present application;

[0057] FIG9 is a circuit diagram of a 45° directional coupler provided in Example 1 of the present application;

[0058] FIG10 is a schematic diagram of the operation of the coupler when the power of the power supply provided in Example 1 of the present application is forward propagating;

[0059] FIG. 11 is a diagram of the reflected voltage V provided in Example 1 of the present application. r Schematic diagram of the operation of the common source terminal of the input coupler;

[0060] FIG12 is a schematic diagram showing the operation of the coupler provided in Example 1 of the present application, wherein the coupling end and the path end respectively output voltages of the same amplitude and opposite phases;

[0061] FIG13 is a schematic diagram showing the operation of the coupler provided in Example 1 of the present application, in which the output voltages of the coupling end and the path end are blocked and reflected by the first power combiner and the second power combiner, respectively;

[0062] FIG14 is a schematic diagram of the operation of the coupler when the reflected power is eliminated according to Example 1 of the present application;

[0063] FIG15 is a flow chart of a method for controlling a balanced power amplifier topology circuit of an RF power supply provided in Example 2 of the present application. DETAILED DESCRIPTION

[0064] The preferred embodiments of the present application are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present application and are used together with the embodiments of the present application to illustrate the principles of the present application, and are not used to limit the scope of the present application.

[0065] Specific embodiment 1 of the present application discloses a balanced power amplifier topology circuit of a radio frequency power supply, and a schematic structural diagram is shown in FIG1 . The balanced power amplifier topology circuit includes a first power divider, a 90° phase shifter, a second power divider, a third power divider, a first matching circuit, a second matching circuit, a first power combiner, a second power combiner, and a coupler; wherein the input end of the first power divider is connected to the output end of the power supply; one output end of the first power divider is connected to the input end of the 90° phase shifter, and the output end of the 90° phase shifter is connected to the input end of the second power divider; the output end of the second power divider is connected to the input end of the first matching circuit, the output end of the first matching circuit is connected to the input end of the first power combiner, and the output end of the first power combiner is connected to the path end of the coupler; the other output end of the first power divider is directly connected to the input end of the third power divider; the output end of the third power divider is connected to the input end of the second matching circuit, the output end of the second matching circuit is connected to the input end of the second power combiner, and the output end of the second power combiner is connected to the coupling end of the coupler; the common source end of the coupler is connected to a load; the first matching circuit and the second matching circuit each include N reference matching circuits; N ≥ 2, and N is an integer; the reference matching circuit includes an input matching circuit, a radio frequency power amplifier, and an output matching circuit connected in sequence.

[0066] Preferably, the balanced power amplifier topology circuit further includes a control module. This control module is configured to measure and process the actual input power of the load when no reflected power is generated at the common source end of the coupler to obtain a power supply output power control signal; and to adjust the output power of the power supply based on the power supply output power control signal. By providing this control module, the output power of the power supply can be gradually adjusted to prevent energy overshoot. Specifically, in the control module, PID control is performed on the deviation between the ideal input power and the actual input power of the load to obtain the power supply output power control signal.

[0067] In addition, the balanced power amplifier topology circuit in this embodiment also includes a voltage sensor, a current sensor, and a DSP; wherein the voltage sensor and the current sensor are used to collect the voltage and current at the common source end of the coupler, respectively; the DSP calculates the forward power and reflected power at the common source end of the coupler based on the voltage and current to determine whether the balanced power amplifier topology circuit generates reflected power. During the specific implementation process, the DSP calculates the forward power and reflected power based on the size and phase of the sampling signal at the common source end of the coupler detected by the voltage sensor and the current sensor. The forward power and reflected power can be considered as the power flowing to the load and the power reflected from the load, respectively. The power dissipated in the load is the forward power minus the reflected power, which is called the load power.

[0068] Preferably, the second power divider and the third power divider are both 1-to-N power dividers; the first power combiner and the second power combiner are both N-to-1 power combiners; each output end of the second power divider and the third power divider is respectively connected to the input end of a reference matching circuit; each input end of the first power combiner and the second power combiner is respectively connected to the output end of a reference matching circuit. Preferably, the reference matching circuit also includes a DC isolation module connected after the output matching circuit; in this case, the input end of the input matching circuit serves as the input end of the reference matching circuit, and the output end of the DC isolation module serves as the output end of the reference matching circuit. The structural diagram of the balanced power amplifier topology circuit of the RF power supply when N is 3 is shown in Figure 2.

[0069] Below, the functions of each component in the balanced power amplifier topology circuit are introduced as follows:

[0070] The first power divider is a one-to-two power splitter. A one-to-two power splitter is used to split a single input signal into two equal signals, with the two signals having the same amplitude, phase, and power. Furthermore, the input impedance of the first power splitter's input and the output impedance of its output are both the characteristic impedance of the power source, matching the characteristic impedance of the power source to eliminate reflected power caused by impedance mismatch. By way of example, the first power splitter uses a Wilkinson one-to-two power splitter. The circuit diagram of the Wilkinson one-to-two power splitter is shown in Figure 3. In Figure 3, one end of capacitor C5 is grounded, and the other end of capacitor C5 is connected to one end of inductor L3 and one end of inductor L4, respectively. The other end of inductor L3 is connected to one end of capacitor C6, one end of capacitor C8, and one end of resistor R1, respectively. The other ends of capacitor C6 and capacitor C8 are both grounded. The other end of inductor L4 is connected to one end of capacitor C7, one end of capacitor C9, and one end of resistor R2, respectively. The other ends of capacitor C7 and capacitor C9 are both grounded. The other end of resistor R1 is connected to the other end of resistor R2. The other end of capacitor C5 is used as the input end of the Wilkinson 1-to-2 power divider, one end of resistor R1 is used as one output end of the Wilkinson 1-to-2 power divider, and one end of resistor R2 is used as the other output end of the Wilkinson 1-to-2 power divider.

[0071] The 90° phase shifter shifts the phase of the received signal by 90°, while keeping the amplitude unchanged. For example, a circuit diagram of the 90° phase shifter is shown in FIG4 . In FIG4 , one end of capacitor C10 and one end of capacitor C11 are both grounded, and an inductor L5 is connected between the other ends of capacitor C10 and C11. One end of capacitor C10 (or one end of capacitor C11) serves as the input end of the 90° phase shifter, and one end of capacitor C11 (or one end of capacitor C10) serves as the output end of the 90° phase shifter.

[0072] In this embodiment, the second and third power dividers divide a single input signal into N signals, each with the same amplitude, phase, and power. Furthermore, the input impedances of the second and third power dividers are both the characteristic impedance of the power source. The output impedances of the N outputs of the second and third power dividers are equal, and the equivalent impedance of the output impedances of the N outputs is the characteristic impedance of the power source. For example, when N is 3, the second and third power dividers can utilize a Wilkinson 1-to-3 power divider. A circuit diagram of the Wilkinson 1-to-3 power divider is shown in Figure 5. In Figure 5, one end of capacitor C12 is grounded, and the other end of capacitor C12 is connected to one end of inductor L6, one end of inductor L7, and one end of inductor L8, respectively. The other end of inductor L6 is connected to one end of capacitor C12, one end of capacitor C15, and one end of resistor R3, respectively. The other ends of capacitor C12 and C15 are both grounded. The other end of inductor L7 is connected respectively to one end of capacitor C13, one end of capacitor C16, one end of resistor R4, and the other end of capacitor C13 and the other end of capacitor C16 are all ground connection. The other end of inductor L8 is connected respectively to one end of capacitor C14, one end of capacitor C17, one end of resistor R5, and the other end of capacitor C14 and the other end of capacitor C17 are all ground connection. The other end of resistor R3, the other end of resistor R4 and the other end of resistor R5 are connected. Use the other end of capacitor C12 as the input end of Wilkinson's one-point-three power divider, use one end of resistor R3 as the first output end of Wilkinson's one-point-three power divider, use one end of resistor R4 as the second output end of Wilkinson's one-point-three power divider, and use one end of resistor R5 as the third output end of Wilkinson's one-point-three power divider.

[0073] The input matching circuit is used to transform the output impedance of one output end of the second power divider or the third power divider into the input impedance of the radio frequency power amplifier, so that the output impedance of the output end of the second power divider or the third power divider is conjugate matched with the input impedance of the radio frequency power amplifier after being transformed by the input matching circuit.

[0074] The RF power amplifier amplifies the input RF low-power signal into a RF high-power signal and converts the input DC energy into AC energy. The output end of the input matching circuit is connected to the gate of the RF power amplifier, the drain of the RF power amplifier is connected to the input end of the output matching circuit, the drains of all RF power amplifiers are also commonly connected to the power supply VDC, and the sources of all RF power amplifiers are grounded. For example, the RF power amplifier can directly use a field-effect transistor, or can use the RF power amplifier circuit shown in Figure 6. In Figure 6, one end of capacitor C24 is connected to one end of inductor L13, the other end of inductor L13 is connected to one end of resistor R9, the other end of resistor R9 is respectively connected to one end of capacitor C26 and one end of capacitor C25, one end of capacitor C26 is respectively connected to the drain of the junction field-effect transistor, one end of resistor R10, one end of resistor C28, the cathode of the diode and one end of inductor L15, and the other end of inductor L15 is connected to one end of inductor C29. One end of resistor C25 is also connected to the gate of the MOS transistor. The drain of the MOS transistor is connected to the other end of resistor R10 and the other end of resistor C28. The other end of inductor C25 is connected to the source of the MOS transistor, the gate of the junction field effect transistor, one end of inductor L14, and one end of capacitor C27. The other end of capacitor C24, the other end of inductor L14, the other end of capacitor C27, and the other end of capacitor C29 are all connected. One end of capacitor C24 serves as the gate of the RF power amplifier, the other end of capacitor C24 serves as the source of the RF power amplifier, and one end of capacitor C29 serves as the drain of the RF power amplifier.

[0075] The output matching circuit is used to transform the output impedance of the RF power amplifier to the input impedance of one input terminal of the first power combiner or the second power combiner, so that the output impedance of the RF power amplifier, after transformation by the output matching circuit, is conjugate matched to the input impedance of one input terminal of the first power combiner or the second power combiner. During specific implementation, the RF power amplifier will have a corresponding optimally matched operating impedance (i.e., optimal impedance). Only when the RF power amplifier operates at its optimal operating impedance can the operating power and efficiency be optimized. Therefore, selecting unused RF power tubes will affect the optimal impedance matched by the output matching circuit to the RF power amplifier. At the same time, the optimal impedance is not a fixed value and is determined based on the selected unused RF power amplifier. For example, when N is 3 and the characteristic impedance of the power supply is 50 ohms, the output impedance of the RF power amplifier tube is matched to the optimal impedance from the input impedance of 12.5 ohms of one input terminal of the first power combiner or the second power combiner. The circuit diagram of the output matching circuit is shown in Figure 7. In Figure 7, one end of the inductor L12 is connected to one end of the capacitor C22 and one end of the capacitor C23, respectively, and the other end of the capacitor C22 is grounded. The other end of the inductor L12 is used as the input end of the output matching circuit, and the other end of the capacitor C23 is used as the output end of the output matching circuit.

[0076] The DC isolation module separates DC and AC and filters out DC signals.

[0077] The first power combiner and the second power combiner are configured to combine N power signals of equal amplitude into one power signal. The output impedances of the output terminals of the first power combiner and the second power combiner are both the characteristic impedance of the power source; the input impedances of the N input terminals of the first power combiner and the second power combiner are equal, and the equivalent impedance of the input impedances of the N input terminals is the characteristic impedance of the power source. For example, when N is 3 and the characteristic impedance of the power source is 50 ohms, the first power combiner or the second power combiner matches the output impedance of 50 ohms at the output terminal to the input impedance of 12.5 ohms at one input terminal. The first power combiner and the second power combiner may utilize a Wilkinson three-in-one power combiner, the circuit diagram of which is shown in FIG8 . In FIG8 , one end of capacitor C19 is connected to one end of resistor R6 and one end of inductor L9, respectively; one end of capacitor C20 is connected to one end of resistor R7 and one end of inductor L10, respectively; and one end of capacitor C21 is connected to one end of resistor R8 and one end of inductor L11, respectively. The other end of inductor C19, the other end of inductor C20, and the other end of inductor C21 are all grounded. The other end of resistor R6, the other end of resistor R7, and the other end of resistor R8 are all grounded. The other end of inductor L9, the other end of inductor L10, and the other end of inductor L11 are all connected to one end of capacitor C18, and the other end of capacitor C18 is grounded. One end of capacitor C19, one end of capacitor C20, and one end of capacitor C21 serve as the first input, second input, and third input of the Wilkinson three-in-one power combiner, respectively, and one end of capacitor C18 serves as the output of the Wilkinson three-in-one power combiner.

[0078] The coupler in this embodiment is preferably a 45° coupler. The circuit diagram of the 45° directional coupler is shown in Figure 9, including: capacitor C1, capacitor C2, capacitor C3 and capacitor C4, coupled inductor L1 and coupled inductor L2; wherein, one end of capacitor C1 is connected to one end of coupled inductor L1, and the other end of coupled inductor L1 is connected to one end of capacitor C2; one end of capacitor C3 is connected to one end of coupled inductor L2, and the other end of coupled inductor L1 is connected to one end of capacitor C4; the other end of capacitor C1, the other end of capacitor C3, the other end of capacitor C2 and the other end of capacitor C4 are all grounded. As can be seen from Figure 9, the coupler is an x- and y-axis symmetrical structure, so each port can be used as an input port (common source terminal). Therefore, in the circuit diagram of the coupler shown in Figure 9, at the four ports of the two coupled inductors, one port is arbitrarily determined as the common source terminal, the diagonal port of the common source terminal is the isolation terminal, and the remaining two ports are respectively the path terminal and the coupling terminal. For example, in Figure 9, one end of the coupled inductor L1 serves as the coupler's path port (Port 1) and common source port (Port 2), respectively. One end of the coupled inductor L2 serves as the coupler's isolation port (Port 3) and coupling port (Port 4), respectively. In this embodiment, the coupler's isolation port is grounded via resistor R0.

[0079] Below, taking Figure 2 as an example (N=3), the working process of the balanced power amplifier topology circuit is discussed from two perspectives: in the direction of power propagation in the forward direction and when the impedance of the load does not match the impedance of the power supply and the RF transmission line:

[0080] (1) In the direction of forward power propagation:

[0081] The power supply is split into two equal voltages of equal amplitude and phase by the first power divider. A 90° phase shifter ensures that the voltages input to the second and third power dividers have the same amplitude and a 90° phase difference. The second and third power dividers each split the received voltage into three equal voltages of equal amplitude and phase.

[0082] At this point, the amplitude and phase of the incident voltages to RF power amplifiers A, B, and C are identical, as are the amplitude and phase of the incident voltages to RF power amplifiers E, F, and G. The amplitudes of the incident voltages to RF power amplifiers A, B, and C are identical, and their phases differ by 90°. RF power amplifiers A, B, and C are each sequentially fed through their corresponding output matching circuits and DC blocking modules before being input into a first power combiner. The first power combiner combines the three matched amplified powers into one power path, which is then input into the coupler's path. RF power amplifiers E, F, and G are each sequentially fed through their corresponding output matching circuits and DC blocking modules before being fed into a second power combiner. The second power combiner combines the three matched amplified powers into one power path, which is then input into the coupler's path. Therefore, the amplitudes of the voltages output from the first and second power combiners are equal, and their phases still differ by 90°.

[0083] The working diagram of the coupler when the power is forward propagating is shown in Figure 10. Assume that the input size of the coupler is The voltage with a phase of 45°, the input size of the coupling end of the coupler is The voltage with a phase of -45°. K1 and K2 represent the amplification of the first matching circuit and the second matching circuit respectively, and the two are equal. At this time, the common source end of the coupler is connected to the load, and the output size is The voltage has a phase of 0°. The coupler's isolation terminal is grounded via resistor R0, outputting voltages with opposite phases. Ideally, the output power at the coupler's common source terminal is the sum of the input power at the coupler's path and coupled terminals.

[0084] (2) When the impedance of the load does not match the impedance of the power supply and transmission line:

[0085] The reflected power P is generated at the common source end of the coupler. r , assuming the corresponding reflected voltage is V r At this time, the coupler and the first power combiner and the second power combiner can eliminate the influence of the reflected power on the power supply. The reflected power elimination process refers to Figures 11 to 14. When the reflected power is generated, the reflected voltage V rThe common source terminal of the input coupler is shown in Figure 11. After the coupler is decomposed, voltages with equal amplitude and opposite phase are output through the coupling terminal and the path terminal of the coupler, respectively, as shown in Figure 12. The output voltages of the coupling terminal and the path terminal of the coupler are blocked and reflected by the second power combiner and the first power combiner, respectively, as shown in Figure 13. τ1 and τ2 represent the reflection coefficients of the first matching circuit and the second matching circuit, respectively, and are equal. The voltages blocked and reflected by the second power combiner and the first power combiner are input through the coupling terminal and the path terminal of the coupler, respectively, and the common source terminal of the coupler outputs voltages with equal amplitude and opposite phase, eliminating the reflected power, as shown in Figure 14. Meanwhile, although the output voltages of the common source terminal and the isolation terminal of the coupler have the same amplitude, the isolation terminal of the coupler is grounded after passing through resistor R0, causing the power output from the isolation terminal of the coupler to be dissipated as heat. Therefore, the reflected power is blocked and eliminated by the coupler, the second power combiner, and the first power combiner, preventing it from affecting the power supply.

[0086] Based on the above analysis, it can be seen that in the balanced power amplifier topology circuit of the RF power supply provided in this embodiment, two paths are set to suppress energy overshoot:

[0087] (1) Eliminate interference by utilizing the proposed matching circuit, 45° directional coupler, and the inherent working properties of the power combiner to prevent reflected power from affecting the power supply. In the matching circuit, reflected power is minimized through stable impedance matching; at the coupler and two power couplers, part of the generated reflected power is transmitted to the ground terminal, and part is offset by voltages of equal amplitude and opposite phase.

[0088] (2) PID regulation: Through PID regulation, the output power is gradually stabilized within the normal range, the system is stabilized when disturbed, and energy overshoot is suppressed.

[0089] In summary, the balanced power amplifier topology circuit of the RF power supply provided in this embodiment adds a balanced power amplifier topology circuit between the power supply and the load, so that the generated reflected power does not affect the power supply. At the same time, PID feedback regulation is added. The balanced power amplifier and control module jointly ensure that the output of the power supply is stable within a predetermined range and can effectively suppress energy overshoot. The beneficial effects of this embodiment are specifically described as follows:

[0090] (1) The circuit structure of the balanced power amplifier topology circuit is simple, and the devices used in the circuit are all commonly used devices in this field. It is easy to implement and does not require a complex circuit network or the calculation of too many parameters.

[0091] (2) Two power combiners and a coupler are used to solve the energy overshoot problem caused by reflected power. This solution is not affected by load changes and does not need to consider control accuracy and delay issues, making it more stable.

[0092] (3) Balanced amplifiers have good input and output matching characteristics and can amplify power at the same time.

[0093] (4) A simple PID control module automatically adjusts the output power of the power supply to ensure that the load receives the predetermined input power, while preventing energy overshoot from occurring during the process of the load receiving the predetermined input power.

[0094] (5) Compared with 90° or other couplers, the 45° coupler proposed in this embodiment can ensure that the energy output from the two ports is the same, better reduce power loss during transmission, and better achieve energy overshoot suppression function.

[0095] A specific embodiment 2 of the present application discloses a method for controlling a balanced power amplifier topology circuit of a radio frequency power supply, the flow chart of which is shown in FIG15 . The method includes the following steps:

[0096] Step S1: using a first power divider and a 90° phase shifter to process the output signal of the power supply so that the amplitudes of the voltages input to the second power divider and the third power divider are the same and the phases thereof differ by 90°;

[0097] Step S2: decomposing the voltage input to the second power divider into N paths with the same amplitude and phase, matching and amplifying the power through a first matching circuit, combining the N paths of matched and amplified power into one path of power using a first power combiner, and then inputting the power to the coupler's path end. Simultaneously, decomposing the voltage input to the third power divider into N paths with the same amplitude and phase, matching and amplifying the power through a second matching circuit, combining the N paths of matched and amplified power into one path of power using a second power combiner, and then inputting the power to the coupler's path end.

[0098] Step S3: If the common source end of the coupler does not generate reflected power, measure and process the actual input power of the load to obtain an output power control signal of the power supply, and adjust the output power of the power supply based on the output power control signal of the power supply;

[0099] Step S4: If reflected power is generated at the common source end of the coupler, the reflected power is eliminated by using the coupler, the first power combiner, and the second power combiner.

[0100] In step S4, specifically perform:

[0101] Step S41: a reflected voltage is input from the common source terminal of the coupler, and then voltages with the same amplitude and a phase difference of 90° are output from the path terminal and the coupling terminal of the coupler respectively;

[0102] Step S42: The voltages outputted from the channel end and the coupled end of the coupler are blocked by the first power combiner and the second power combiner, respectively. The amplitudes of the voltages outputted from the channel end and the coupled end of the coupler change by a multiple of the reflection coefficients of the first power combiner and the second power combiner, respectively, while the phases remain unchanged.

[0103] Step S43: the voltage reflected and blocked by the first power combiner and the second power combiner is inputted from the path end and the coupling end of the coupler respectively, and the common source end of the coupler outputs voltages with opposite phases and equal amplitudes, and the reflected power is eliminated.

[0104] It should be noted that the specific implementation process of the embodiment of the method of the present application can be referred to the above circuit embodiment, and this embodiment will not be repeated here.

[0105] Since the principles of this embodiment are the same as those of the above circuit embodiment, the present method embodiment also has the corresponding technical effects of the above circuit embodiment.

[0106] Those skilled in the art will appreciate that all or part of the process steps of the above-described embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, such as a magnetic disk, an optical disk, a read-only memory, or a random access memory.

[0107] The above is only a preferred specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in this application should be covered by the scope of protection of the present application.

Claims

1. A balanced power amplifier topology circuit of a radio frequency power supply, characterized in that: The balanced power amplifier topology circuit includes a first power divider, a 90° phase shifter, a second power divider, a third power divider, a first matching circuit, a second matching circuit, a first power combiner, a second power combiner and a coupler; wherein, The input end of the first power divider is connected to the output end of the power supply; one output end of the first power divider is connected to the input end of the 90° phase shifter, and the output end of the 90° phase shifter is connected to the input end of the second power divider; the output end of the second power divider is connected to the input end of the first matching circuit, the output end of the first matching circuit is connected to the input end of the first power combiner, and the output end of the first power combiner is connected to the path end of the coupler; The other output end of the first power divider is directly connected to the input end of the third power divider; the output end of the third power divider is connected to the input end of the second matching circuit, the output end of the second matching circuit is connected to the input end of the second power combiner, and the output end of the second power combiner is connected to the coupling end of the coupler; the common source end of the coupler is connected to the load; The first matching circuit and the second matching circuit both include N reference matching circuits; N≥2, and N is an integer; the reference matching circuit includes an input matching circuit, a radio frequency power amplifier, and an output matching circuit connected in sequence.

2. The balanced power amplifier topology circuit of the radio frequency power supply according to claim 1, characterized in that: The second power divider and the third power divider are both one-to-N power dividers; the first power combiner and the second power combiner are both N-to-1 power combiners; Each output end of the second power divider and the third power divider is connected to an input end of a reference matching circuit respectively; each input end of the first power combiner and the second power combiner is connected to an output end of a reference matching circuit respectively.

3. The balanced power amplifier topology circuit of the radio frequency power supply according to claim 2, characterized in that: The reference matching circuit also includes a DC isolation module connected after the output matching circuit; The input end of the input matching circuit serves as the input end of the reference matching circuit, and the output end of the DC isolation module serves as the output end of the reference matching circuit.

4. The balanced power amplifier topology circuit of the radio frequency power supply according to claim 3, characterized in that: The input impedances of the input ends of the second power divider and the third power divider are both characteristic impedances of the power supply; the output impedances of the N output ends of the second power divider and the third power divider are equal, and the equivalent impedance of the output impedances of the N output ends is the characteristic impedance of the power supply; The output impedances of the output ends of the first power combiner and the second power combiner are both characteristic impedances of the power supply; the input impedances of the N input ends of the first power combiner and the second power combiner are equal, and the equivalent impedance of the input impedances of the N input ends is the characteristic impedance of the power supply.

5. The balanced power amplifier topology circuit of the radio frequency power supply according to claim 4, characterized in that: The input matching circuit is used to transform the output impedance of one output end of the second power divider or the third power divider to the input impedance of the RF power amplifier, so that the output impedance of the output end of the second power divider or the third power divider is conjugate matched with the input impedance of the RF power amplifier after being transformed by the input matching circuit.

6. The balanced power amplifier topology circuit of the radio frequency power supply according to claim 5, characterized in that: The output matching circuit is used to transform the output impedance of the RF power amplifier to the input impedance of one input end of the first power combiner or the second power combiner, so that the output impedance of the RF power amplifier is conjugate matched with the input impedance of one input end of the first power combiner or the second power combiner after being transformed by the output matching circuit.

7. The balanced power amplifier topology circuit of the radio frequency power supply according to any one of claims 1 to 6, characterized in that: When reflected power is generated at the passage end of the coupler, the reflected power is eliminated by using the coupler, the first power combiner and the second power combiner.

8. The balanced power amplifier topology circuit of the radio frequency power supply according to claim 7, characterized in that: The balanced power amplifier topology circuit also includes a control module; The control module is used to measure and process the actual input power of the load when the common source end of the coupler does not generate reflected power, obtain the power supply output power control signal; and adjust the output power of the power supply based on the power supply output power control signal.

9. A control method for a balanced power amplifier topology circuit of a radio frequency power supply, characterized in that: The method comprises: The output signal of the power supply is processed by the first power divider and the 90° phase shifter so that the amplitudes of the voltages input to the second power divider and the third power divider are the same and the phases are different by 90°; The voltage input to the second power divider is decomposed into N paths with the same amplitude and phase, matched and amplified by the first matching circuit, and the power of the N paths is combined into one path by the first power combiner and then input to the channel end of the coupler; The voltage input to the third power divider is decomposed into N paths with the same amplitude and phase, matched and amplified by the second matching circuit, and the power of the N paths is combined into one path by the second power combiner and then input into the coupling end of the coupler; If the common source end of the coupler does not generate reflected power, measure and process the actual input power of the load to obtain an output power control signal of the power supply, and adjust the output power of the power supply based on the output power control signal of the power supply; If the common source end of the coupler generates reflected power, the coupler and the first power combiner and the second power combiner are used to eliminate the reflected power.

10. The control method of the balanced power amplifier topology circuit of the radio frequency power supply according to claim 9, characterized in that: The method of eliminating the reflected power by using a coupler, a first power synthesizer, and a second power synthesizer includes: The reflected voltage is input from the common source end of the coupler, and then the voltages with the same amplitude and a phase difference of 90° are output from the channel end and the coupling end of the coupler respectively; The voltage outputted from the channel end and the coupling end of the coupler is blocked by the first power combiner and the second power combiner respectively, and the voltage amplitude outputted from the channel end and the coupling end of the coupler is respectively The reflection coefficients of the power combiner and the second power combiner change by multiples, but the phase remains unchanged; The voltages blocked and reflected by the first power combiner and the second power combiner are input from the passage end and the coupling end of the coupler respectively, and the common source end of the coupler outputs voltages with opposite phases and equal amplitudes, and the reflected power is eliminated.

Images