A radio frequency power supply sampling and control circuit and method, radio frequency power supply

Abstract

The application provides a radio frequency power supply sampling and control circuit and method and a radio frequency power supply, and relates to the technical field of power electronics. The circuit comprises a sampling unit, a first regulating branch, a second regulating branch and a cross limiting circuit. The radio frequency power supply sampling and control circuit generates a feedback signal representing incident power and reflected power through the sampling unit, and carries out continuous time analog regulation by the first and second regulating branches respectively. The cross limiting circuit makes the first limiting branch execute incident power regulation or makes the second limiting branch clamp the amplitude control node according to the reflected power state, so as to generate an amplitude control signal of the radio frequency power amplifier, and realize quick and smooth switching between incident power control and reflected power limitation.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and more specifically, to a radio frequency power supply sampling and control circuit and method, and a radio frequency power supply. Background Technology

[0002] In related technologies, the RF power supply adopts incident power closed-loop control of RF output power and sets up a reflected power protection branch. When the reflected power exceeds the protection threshold due to load mismatch, the reflected power protection branch clamps the given node, error input node or power control node of the main control loop, thereby reducing the RF output power.

[0003] However, in the aforementioned control methods, the incident power control branch and the reflected power protection branch may employ different signal processing methods and possess different gain characteristics and dynamic response characteristics. In some schemes, the reflected power protection branch directly intervenes in the main control loop after the reflected power exceeds the protection threshold. The lack of coordinated and continuous adjustment between the incident power control branch and the reflected power protection branch can easily cause abrupt changes in the input or output control signals of the main control loop. When the RF power supply switches between normal load and load mismatch states, output power fluctuations, loop regulation oscillations, or unstable reflected power limiting responses may occur. Summary of the Invention

[0004] The problem this invention addresses is how to achieve a fast and smooth switching between radio frequency power supply incident power control and reflected power limitation.

[0005] To address the above problems, this invention provides an RF power supply sampling and control circuit and method, and an RF power supply.

[0006] In a first aspect, the present invention provides an radio frequency power supply sampling and control circuit, comprising: A sampling unit is used to generate a first feedback signal characterizing the incident power and a second feedback signal characterizing the reflected power based on the output signal of the radio frequency power supply. The first adjustment branch is used to receive the first given signal and the first feedback signal, and to perform continuous-time analog adjustment based on the deviation between the first given signal and the first feedback signal to generate the first adjustment signal; The second adjustment branch is used to receive the second given signal and the second feedback signal, and to perform continuous-time analog adjustment based on the deviation between the second given signal and the second feedback signal to generate the second adjustment signal; A cross-limiting circuit includes a first limiting branch connected to the first adjustment branch and a second limiting branch connected to the second adjustment branch. The output terminals of the first limiting branch and the second limiting branch are respectively connected to an amplitude control node. The cross-limiting circuit is used to cause the first limiting branch to adjust the signal at the amplitude control node according to the first adjustment signal when the second feedback signal does not meet the reflection limiting condition, and to cause the second limiting branch to clamp the signal at the amplitude control node according to the second adjustment signal when the second feedback signal meets the reflection limiting condition, so as to generate an amplitude control signal for adjusting the output power of the RF power amplifier.

[0007] Optionally, the first given signal is used to characterize the target incident power, and the second given signal is used to characterize the reflection power limit value; the reflection limiting condition includes the reflection power characterized by the second feedback signal being greater than or equal to the reflection power limit value.

[0008] Optionally, the first adjustment branch includes a first error comparison circuit and a first proportional-integral adjustment circuit. The first error comparison circuit is used to generate a first deviation signal based on the first given signal and the first feedback signal, and the first proportional-integral adjustment circuit is used to generate the first adjustment signal based on the first deviation signal. And / or, the second adjustment branch includes a second error comparison circuit and a second proportional-integral adjustment circuit, wherein the second error comparison circuit is used to generate a second deviation signal based on the second given signal and the second feedback signal, and the second proportional-integral adjustment circuit is used to generate a second adjustment signal based on the second deviation signal.

[0009] Optionally, the first limiting branch includes a first transistor limiting circuit and a first cross-limiting diode, and the second limiting branch includes a second transistor limiting circuit and a second cross-limiting diode; The anode of the first cross-limiting diode is connected to the output terminal of the first transistor limiting circuit, and the cathode of the first cross-limiting diode is connected to the output terminal of the second proportional-integral adjustment circuit. The anode of the second cross-limiting diode is connected to the output terminal of the second transistor limiting circuit, and the cathode of the second cross-limiting diode is connected to the output terminal of the first proportional-integral adjustment circuit.

[0010] Optionally, a first bypass resistor is connected in parallel across the two ends of the first cross-limiting diode, and a second bypass resistor is connected in parallel across the two ends of the second cross-limiting diode.

[0011] Optionally, the RF power sampling and control circuit further includes a signal modulation unit, which is used to receive the amplitude control signal and the RF reference signal, and adjust the amplitude of the RF reference signal according to the amplitude control signal to generate an RF control signal for controlling the output power of the RF power amplifier.

[0012] Optionally, the first given signal includes a power given signal that maintains a corresponding power given value in different time intervals and undergoes a step change between adjacent time intervals; When the second feedback signal does not meet the reflection limiting condition, the first adjustment branch is used to continuously adjust the first adjustment signal according to the deviation between the power setpoint signal and the first feedback signal, so that the incident power represented by the first feedback signal follows the change of the corresponding power setpoint value in each of the time intervals.

[0013] Optionally, the sampling unit includes a current sampling unit, a voltage sampling unit, a calibration unit, and a detection unit; The current sampling unit is used to collect the radio frequency current in the output circuit of the radio frequency power supply and generate a radio frequency current sampling signal. The voltage sampling unit is used to acquire the radio frequency voltage in the output circuit of the radio frequency power supply and generate a radio frequency voltage sampling signal; The calibration unit is used to calibrate at least one of the phase relationship and amplitude relationship between the radio frequency current sampling signal and the radio frequency voltage sampling signal; The detection unit is used to perform detection processing based on the calibrated radio frequency current sampling signal and the radio frequency voltage sampling signal to generate the first feedback signal and the second feedback signal.

[0014] In a second aspect, the present invention also provides a radio frequency power supply, including the radio frequency power supply sampling and control circuit as described in the first aspect.

[0015] Thirdly, the present invention also provides a radio frequency power supply sampling and control method, comprising: A first feedback signal characterizing the incident power and a second feedback signal characterizing the reflected power are generated based on the output signal of the radio frequency power supply. Based on the deviation between the first given signal and the first feedback signal, continuous-time simulation adjustment is performed to generate the first adjustment signal; Based on the deviation between the second given signal and the second feedback signal, continuous-time simulation adjustment is performed to generate a second adjustment signal; Based on the first adjustment signal and the second adjustment signal, cross-limiting processing is performed on the signal at the amplitude control node; The cross-limiting processing includes: When the second feedback signal does not meet the reflection limiting condition, the signal at the amplitude control node is adjusted by the first limiting branch according to the first adjustment signal; when the second feedback signal meets the reflection limiting condition, the signal at the amplitude control node is clamped by the second limiting branch according to the second adjustment signal to generate an amplitude control signal for adjusting the output power of the RF power amplifier.

[0016] The beneficial effects of the RF power supply sampling and control circuit and method of the present invention are as follows: The RF power supply sampling and control circuit of the present invention generates a first feedback signal characterizing the incident power and a second feedback signal characterizing the reflected power through a sampling unit, and performs continuous-time simulation adjustment according to the deviation between the corresponding given signal and the feedback signal through a first adjustment branch and a second adjustment branch, respectively, to generate a first adjustment signal and a second adjustment signal. The first adjustment signal and the second adjustment signal are respectively applied to the same amplitude control node through a first limiting branch and a second limiting branch: when the second feedback signal does not meet the reflection limiting condition, the first limiting branch adjusts the signal at the amplitude control node according to the first adjustment signal to achieve closed-loop adjustment of the RF power supply incident power; when the second feedback signal meets the reflection limiting condition, the second limiting branch clamps the signal at the amplitude control node according to the second adjustment signal to limit the output power of the RF power amplifier. Therefore, incident power control and reflected power limiting can be coordinated around the same amplitude control signal, stably adjusting the incident power when the load is normal, and timely limiting the output power of the RF power amplifier when the load is mismatched. This helps to reduce the possibility of abrupt changes in the amplitude control signal during the switching between the two control states, reduce output power fluctuations and loop regulation oscillations, improve the response timeliness of reflected power limiting, realize fast, continuous and smooth switching between incident power control and reflected power limiting, and reduce the risk of damage to the RF power amplifier caused by load mismatch. Attached Figure Description

[0017] Figure 1 This is a structural block diagram of an RF power supply sampling and control circuit in an embodiment of the present invention; Figure 2 This is a schematic diagram of the control link principle of the radio frequency power supply sampling and control circuit in an embodiment of the present invention; Figure 3 This is a partial circuit structure diagram of the radio frequency power supply sampling and control circuit in an embodiment of the present invention; Figure 4 This is a schematic diagram of the stepped waveforms of the incident and reflected radio frequency voltages of the radio frequency power supply under matched load conditions in an embodiment of the present invention. Figure 5 This is a schematic diagram of the control waveforms of the incident and reflected radio frequency voltages of the radio frequency power supply under a sudden load mismatch state in an embodiment of the present invention. Detailed Implementation

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0020] Combination Figure 1 As shown, an embodiment of the present invention provides an RF power supply sampling and control circuit, comprising: A sampling unit is used to generate a first feedback signal characterizing the incident power and a second feedback signal characterizing the reflected power based on the output signal of the radio frequency power supply. The first adjustment branch is used to receive a first given signal and a first feedback signal, and to perform continuous-time analog adjustment based on the deviation between the first given signal and the first feedback signal to generate a first adjustment signal. The second adjustment branch is used to receive the second given signal and the second feedback signal, and to perform continuous-time analog adjustment based on the deviation between the second given signal and the second feedback signal to generate the second adjustment signal; A cross-limiting circuit includes a first limiting branch connected to a first adjustment branch and a second limiting branch connected to a second adjustment branch. The output terminals of the first and second limiting branches are respectively connected to an amplitude control node. The cross-limiting circuit is used to cause the first limiting branch to adjust the signal at the amplitude control node according to the first adjustment signal when the second feedback signal does not meet the reflection limiting condition, and to cause the second limiting branch to clamp the signal at the amplitude control node according to the second adjustment signal when the second feedback signal meets the reflection limiting condition, so as to generate an amplitude control signal for adjusting the output power of the RF power amplifier.

[0021] This embodiment provides an RF power supply sampling and control circuit, which can be used to perform closed-loop regulation of the output power of the RF power supply and limit the output power of the RF power amplifier when impedance mismatch occurs between the RF power supply and the load, resulting in increased reflected power.

[0022] The radio frequency power supply sampling and control circuit includes a sampling unit, a first adjustment branch, a second adjustment branch, and a cross-limiting circuit.

[0023] The sampling unit corresponds to the output side of the RF power supply and is used to generate a first feedback signal and a second feedback signal based on the output signal of the RF power supply. The first feedback signal characterizes the incident power of the RF power supply, and the second feedback signal characterizes the reflected power of the RF power supply. It can be understood that the output signal of the RF power supply contains information reflecting the incident power state and the reflected power state. The sampling unit samples and processes the output signal of the RF power supply, converting the power state at the output side of the RF power supply into feedback signals that can be processed by the subsequent adjustment branch. The first feedback signal changes with the incident power to reflect the current incident power state of the RF power supply; the second feedback signal changes with the reflected power to reflect the current reflected power state of the RF power supply.

[0024] The first adjustment branch receives a first given signal and a first feedback signal, and performs continuous-time analog adjustment based on the deviation between the first given signal and the first feedback signal to generate a first adjustment signal. For example, the first given signal can characterize the expected incident power control target of the RF power supply, and the first feedback signal can characterize the current actual incident power of the RF power supply. The first adjustment branch generates the first adjustment signal based on the deviation between the first given signal and the first feedback signal, adjusting the output power of the RF power amplifier in a direction that reduces the deviation. For example, when the actual incident power is lower than the incident power control target, the output power of the RF power amplifier can be adjusted to increase using the first adjustment signal; when the actual incident power is higher than the incident power control target, the output power of the RF power amplifier can be adjusted to decrease using the first adjustment signal. As the actual incident power gradually approaches the incident power control target, the deviation between the first given signal and the first feedback signal decreases accordingly, and the adjustment implemented by the first adjustment branch on the first adjustment signal based on this deviation also changes accordingly, thereby causing the incident power of the RF power supply to approach and stabilize at the corresponding incident power control target. The first regulation branch adopts a continuous-time analog regulation method, that is, the first regulation branch generates and adjusts the first regulation signal in the continuous time domain based on the first given signal and the first feedback signal in analog form, so that the first regulation signal can change continuously with the change of the first feedback signal, which is beneficial to improving the continuity and response time of the incident power regulation.

[0025] The second adjustment branch receives a second given signal and a second feedback signal, and performs continuous-time analog adjustment based on the deviation between the second given signal and the second feedback signal to generate a second adjustment signal. For example, the second given signal can characterize a reflected power control target, which may include a reflected power limiting target for limiting the output power of the RF power amplifier. The second feedback signal can characterize the current actual reflected power of the RF power supply. When the RF power supply and load are well matched, less energy is reflected from the load to the RF power supply, and the reflected power characterized by the second feedback signal is at a relatively low level. When the load impedance changes, reducing the matching degree between the RF power supply and the load, the reflected power increases accordingly, and the second feedback signal changes accordingly. The second adjustment branch continuously adjusts the second adjustment signal based on the deviation between the second given signal and the second feedback signal, so that the second adjustment signal can reflect the degree of deviation of the current reflected power from the reflected power control target. Therefore, the second adjustment branch can continuously generate corresponding analog adjustment results during the reflection power change process, allowing the second adjustment signal to continuously change with the reflection power, providing a control basis for subsequently limiting the output power of the RF power amplifier based on the reflection power state.

[0026] The cross-limiting circuit includes a first limiting branch and a second limiting branch. The first limiting branch is connected to a first adjustment branch and receives a first adjustment signal; the second limiting branch is connected to a second adjustment branch and receives a second adjustment signal. The outputs of the first and second limiting branches are respectively connected to the same amplitude control node. The amplitude control node generates an amplitude control signal, which is used to adjust the output power of the RF power amplifier. In other words, the amplitude control signal is an analog control quantity characterizing the degree of adjustment of the RF power amplifier's output power, and the output power of the RF power amplifier can be adjusted accordingly based on changes in the amplitude control signal. Since both the first and second limiting branches are connected to the same amplitude control node, the first and second adjustment signals do not act on two independent power control objects, but rather adjust or limit the same RF power amplifier output power control quantity through the first and second limiting branches respectively. Therefore, incident power control and reflected power limitation can be coordinated around the same amplitude control signal.

[0027] The reflection limiting condition is used to determine whether the current reflected power has reached a level requiring limitation of the RF power amplifier's output power. The reflection limiting condition can be determined based on the reflected power represented by the second feedback signal. For example, the second feedback signal can be compared with a preset reflection power limit. If the reflected power represented by the second feedback signal has not yet reached a level requiring limitation of the RF power amplifier's output power, the second feedback signal is determined not to meet the reflection limiting condition; if the reflected power represented by the second feedback signal reaches a level requiring limitation of the RF power amplifier's output power, the second feedback signal is determined to meet the reflection limiting condition. The specific expression of the reflection limiting condition can be set according to the signal form and polarity of the second feedback signal, as well as the power control requirements of the RF power supply.

[0028] When the second feedback signal does not meet the reflection limiting condition, it indicates that the current reflected power has not yet reached the state where the RF power amplifier output power needs to be limited. In this state, the second limiting branch does not exert a dominant clamping effect on the signal at the amplitude control node. The first limiting branch adjusts the signal at the amplitude control node according to the first adjustment signal, and the amplitude control signal is therefore mainly determined based on the first adjustment signal. At this time, the RF power supply sampling and control circuit mainly implements closed-loop adjustment based on the incident power: the sampling unit generates a first feedback signal based on the output signal of the RF power supply, the first adjustment branch generates a first adjustment signal based on the deviation between the first given signal and the first feedback signal, and the first limiting branch adjusts the signal at the amplitude control node according to the first adjustment signal, thereby adjusting the output power of the RF power amplifier through the amplitude control signal. After the output power of the RF power amplifier changes, the incident power state of the RF power supply changes accordingly. The sampling unit updates the first feedback signal accordingly, and the first adjustment branch adjusts the first adjustment signal according to the updated deviation, thus forming a closed-loop control process for the incident power, adjusting the incident power of the RF power supply towards the control target corresponding to the first given signal.

[0029] When the load impedance of the RF power supply changes, causing the reflected power to gradually increase, the second feedback signal generated by the sampling unit changes accordingly. The second adjustment branch continuously adjusts the second adjustment signal based on the deviation between the second given signal and the second feedback signal. Before the second feedback signal meets the reflection limiting condition, the first limiting branch still adjusts the signal at the amplitude control node according to the first adjustment signal, while the second adjustment branch generates a corresponding second adjustment signal based on the change in reflected power. When the second feedback signal meets the reflection limiting condition, it indicates that the current reflected power has reached a state where the RF power amplifier output power needs to be limited. The second limiting branch clamps the signal at the amplitude control node according to the second adjustment signal, so that the signal at the amplitude control node is no longer solely determined by the first adjustment signal, but is constrained by the reflected power limitation requirement corresponding to the second adjustment signal. After clamping by the second limiting branch, the RF power amplifier output power control amount corresponding to the amplitude control signal is limited, thereby restricting the RF power amplifier output power from continuing to change in the direction that increases the reflected power. For example, the second limiting branch can change the amplitude control signal in the direction of reducing the output power of the RF power amplifier, thereby limiting the output power of the RF power amplifier and the RF energy transmitted to the load. This helps to reduce the energy reflected from the load to the RF power supply and reduce the situation where the RF power amplifier continuously bears a large amount of reflected power.

[0030] When the second limiting branch clamps the signal at the amplitude control node, the adjustment effect of the first limiting branch based on the first adjustment signal is constrained by the second limiting branch. Even if the output power of the RF power amplifier is limited, and the actual incident power decreases, causing the first adjustment branch to tend to increase the output power of the RF power amplifier, the second limiting branch can still clamp the signal at the amplitude control node based on the second adjustment signal to limit the RF power amplifier output power control amount corresponding to the amplitude control signal. This avoids the situation where the incident power closed-loop control, in order to reduce the deviation between the first given signal and the first feedback signal, continuously increases the output power of the RF power amplifier in a load mismatch state (i.e., the matching degree between the output impedance of the RF power supply and the input impedance of the load decreases, leading to an increase in RF energy reflected from the load to the RF power supply and an increase in reflected power). This allows the reflected power limitation to prioritize constrain power adjustment trends that are detrimental to the safe operation of the RF power amplifier.

[0031] In some embodiments, during the clamping process of the second limiting branch, the first regulating branch can still continuously generate a first regulating signal based on the deviation between the first given signal and the first feedback signal, and the second regulating branch can also continuously generate a second regulating signal based on the deviation between the second given signal and the second feedback signal. When the load condition recovers and the matching degree between the RF power supply and the load improves, the reflected power gradually decreases, and the second feedback signal changes accordingly. When the second feedback signal no longer meets the reflection limiting condition, the second limiting branch releases or weakens the clamping effect on the signal at the amplitude control node, and the first limiting branch can continue to adjust the signal at the amplitude control node based on the current first regulating signal, so that the RF power supply returns to the state of closed-loop regulation mainly based on the incident power. Since both the first and second regulating branches can generate regulating signals based on the corresponding deviation in the continuous time domain, the two regulating results can continuously change with the corresponding feedback signals during the load condition change process, which helps to reduce the possibility of abrupt changes in the amplitude control signal when the control state switches.

[0032] In summary, the RF power supply sampling and control circuit of this embodiment generates a first feedback signal characterizing the incident power and a second feedback signal characterizing the reflected power through a sampling unit. It then uses a first adjustment branch and a second adjustment branch to perform continuous-time analog adjustments based on the deviation between the corresponding given signal and the feedback signal, generating a first adjustment signal and a second adjustment signal. The first and second adjustment signals are applied to the same amplitude control node via the first and second limiting branches, respectively: when the second feedback signal does not meet the reflection limiting condition, the first limiting branch adjusts the signal at the amplitude control node according to the first adjustment signal to achieve closed-loop adjustment of the RF power supply incident power; when the second feedback signal meets the reflection limiting condition, the second limiting branch clamps the signal at the amplitude control node according to the second adjustment signal to limit the output power of the RF power amplifier. Therefore, incident power control and reflected power limiting can be coordinated around the same amplitude control signal, stably adjusting the incident power when the load is normal, and timely limiting the output power of the RF power amplifier when the load is mismatched. This helps to reduce the possibility of abrupt changes in the amplitude control signal during the switching between the two control states, reduce output power fluctuations and loop regulation oscillations, improve the response timeliness of reflected power limiting, realize fast, continuous and smooth switching between incident power control and reflected power limiting, and reduce the risk of damage to the RF power amplifier caused by load mismatch.

[0033] Optionally, continuous-time analog regulation refers to processing the analog signals using a continuous-time analog circuit at least during the analog reception of the first and second feedback signals, the error comparison between the given signal and the feedback signal, the generation of the first and second regulation signals, the cross-limiting, and the generation of the amplitude control signal. The aforementioned feedback closed-loop control process does not require discrete sampling of the feedback signal via a high-speed analog-to-digital converter, nor does it require a digital processor to perform closed-loop power calculations, software algorithm adjustments, and periodic control updates. The first given signal, the second given signal, and the RF reference signal can be provided by analog circuits or digital signal generation circuits external to the RF power supply sampling and control circuit, without affecting the implementation of a continuous-time analog architecture for the feedback closed-loop control link.

[0034] For example, combined Figure 2 As shown, the overall signal link of the RF power supply may include an analog control unit 140 (i.e., an analog control part for implementing the first regulation branch, the second regulation branch, and the cross-limiting circuit), a directional coupler sampling unit 110 (i.e., a current sampling front-end in the sampling unit for acquiring the RF output current), a sampling signal processing unit 120 (i.e., a sampling unit including a voltage sampling part and a signal processing part for implementing calibration, combination, detection, and filtering), an incident voltage differential amplifier unit 111 (i.e., a first differential output circuit in the sampling unit for forming a differential first feedback signal), a reflected voltage differential amplifier unit 112 (i.e., a second differential output circuit in the sampling unit for forming a differential second feedback signal), a constant temperature control unit 121 (i.e., a constant temperature control unit for adjusting the temperature of the temperature-sensitive sampling device in the sampling unit), a signal modulation unit 108, and an RF power amplifier 109. The directional coupler sampling unit 110, the sampling signal processing unit 120, the incident voltage differential amplification unit 111, and the reflected voltage differential amplification unit 112 can collectively constitute the sampling unit; the constant temperature control unit 121 can be an optional component of the RF power supply sampling and control circuit. The RF power amplifier 109 is not a necessary component of the RF power supply sampling and control circuit, but can be a component of the RF power supply.

[0035] The first regulation branch may include an incident voltage error adder 101 (i.e., a first error comparison circuit) and an incident voltage proportional-integral controller 102 (i.e., a first proportional-integral regulation circuit). The incident voltage error adder 101 is used to generate a first deviation signal based on a first given signal and a first feedback signal, and the incident voltage proportional-integral controller 102 is used to generate a first regulation signal based on the first deviation signal.

[0036] The second regulation branch may include a reflected voltage error adder 104 (i.e., a second error comparison circuit) and a reflected voltage proportional-integral controller 105 (i.e., a second proportional-integral regulation circuit). The reflected voltage error adder 104 is used to generate a second deviation signal based on a second given signal and a second feedback signal, and the reflected voltage proportional-integral controller 105 is used to generate a second regulation signal based on the second deviation signal.

[0037] The incident voltage limiter 103 corresponds to the first transistor limiting circuit in the first limiting branch, and is used to generate a first limiting output signal according to the first adjustment signal; the reflected voltage limiter 106 corresponds to the second transistor limiting circuit in the second limiting branch, and is used to generate a second limiting output signal according to the second adjustment signal. The dual-loop cross-limiting unit 107 corresponds to the cross-connection part in the cross-limiting circuit used to form a cross-connection relationship between the first limiting branch and the second limiting branch, and may include a first cross-limiting diode, a second cross-limiting diode, and corresponding connection lines.

[0038] The incident voltage limiter 103 and the first cross-limiting structure corresponding to the first adjustment branch in the dual-loop cross-limiting unit 107 can jointly constitute the first limiting branch; the reflected voltage limiter 106 and the second cross-limiting structure corresponding to the second adjustment branch in the dual-loop cross-limiting unit 107 can jointly constitute the second limiting branch. The incident voltage limiter 103, the reflected voltage limiter 106, and the dual-loop cross-limiting unit 107 together constitute the cross-limiting circuit of this embodiment.

[0039] In the dual-loop cross-limiting unit 107, the node where the first limiting branch and the second limiting branch are connected and function together can be used as an amplitude control node. The signal generated at the amplitude control node by the cross-limiting circuit can be directly used as an amplitude control signal, or it can be proportionally adjusted, level converted, biased adjusted, or impedance transformed by the loop control signal conditioning unit to form an amplitude control signal, and then the amplitude control signal is provided to the signal modulation unit 108.

[0040] The signal modulation unit 108 adjusts the amplitude of the external RF reference signal according to the amplitude control signal to generate an RF control signal. The RF power amplifier 109 amplifies the RF control signal and outputs an RF signal. The directional coupler sampling unit 110 samples the RF current in the output circuit of the RF power amplifier 109 to generate an RF current sampling signal; the voltage sampling part of the sampling signal processing unit 120 samples the RF voltage at the RF output node RF-OUT to generate an RF voltage sampling signal. The sampling signal processing unit 120 performs at least one of the following processes on the RF current sampling signal and the RF voltage sampling signal: calibration, combination, detection, and filtering, to form an incident power sampling signal and a reflected power sampling signal, respectively. The incident voltage differential amplifier unit 111 and the reflected voltage differential amplifier unit 112 form a differential first feedback signal and a second feedback signal based on the incident power sampling signal and the reflected power sampling signal, respectively, and provide the first feedback signal and the second feedback signal to the analog control unit 140, thereby forming a closed-loop control link.

[0041] Figure 2 The RF signal generation circuit represented by DDS is used to provide an RF reference signal and is set independently of the RF power supply sampling and control circuit; the RF power amplifier 109 belongs to the power output section of the RF power supply. For Figure 2 The DDS and RF power amplifier 109 shown are shown in the diagram. The DDS does not constitute a component of the RF power supply sampling and control circuit; the RF power amplifier 109 does not constitute a necessary component of the RF power supply sampling and control circuit, but can be used as a component of the RF power supply.

[0042] Since the feedback closed-loop processing, including feedback signal reception, error comparison, adjustment signal generation, and cross-limiting, can all be completed in the continuous-time analog signal domain, the RF power supply sampling and control circuit does not need to perform periodic discrete sampling of the feedback signal through a high-speed analog-to-digital converter, nor does it require a digital processor to perform closed-loop power calculation, software algorithm adjustment, and periodic control updates. This helps reduce control delays caused by signal conversion and digital computation, and improves the control bandwidth and dynamic response speed of the feedback closed loop. Correspondingly, the feedback closed-loop control link can be mainly implemented using analog devices such as operational amplifiers, resistors, capacitors, transistors, and diodes. This simplifies the control link, reduces the configuration requirements for high-speed analog-to-digital converters and high-performance digital processors, and thus reduces circuit implementation complexity, hardware cost, and debugging and maintenance difficulty.

[0043] Optionally, the first given signal is used to characterize the target incident power, and the second given signal is used to characterize the reflection power limit value; the reflection limiting condition includes the reflection power characterized by the second feedback signal being greater than or equal to the reflection power limit value.

[0044] In this embodiment, the target incident power refers to the incident power that the RF power supply expects to output to the load, and the first given signal is an analog given quantity corresponding to the target incident power. The first feedback signal is used to characterize the current actual incident power of the RF power supply. The first adjustment branch generates a first adjustment signal based on the deviation between the first given signal and the first feedback signal, so as to adjust the actual incident power towards the target incident power. For example, when the actual incident power is lower than the target incident power, the first adjustment signal can adjust the output power of the RF power amplifier to increase; when the actual incident power is higher than the target incident power, the first adjustment signal can adjust the output power of the RF power amplifier to decrease, thereby realizing closed-loop control of the RF power supply's incident power.

[0045] The reflected power limit value refers to the power value preset based on factors such as the RF power amplifier's handling capacity, the RF power supply's protection requirements, and the load's operating characteristics, used to trigger the reflected power limit. The second given signal is an analog given quantity corresponding to the reflected power limit value, and the second feedback signal is used to characterize the current actual reflected power of the RF power supply. The second adjustment branch continuously generates a second adjustment signal based on the deviation between the second given signal and the second feedback signal, enabling the second adjustment signal to change with the actual reflected power relative to the reflected power limit value. It should be noted that the first given signal, the second given signal, the first feedback signal, and the second feedback signal can each be a voltage signal or a current signal with a preset mapping relationship to the corresponding power value, and their specific signal magnitude and direction of change can be determined according to the signal polarity and control logic of the corresponding circuit.

[0046] In this embodiment, the comparison between the actual reflected power represented by the second feedback signal and the reflected power limit value can be used to determine whether the second feedback signal meets the reflection limiting condition. When the actual reflected power represented by the second feedback signal is less than the reflected power limit value, the second feedback signal does not meet the reflection limiting condition, indicating that the current reflected power is still within the allowable range. At this time, the second limiting branch does not form an effective clamp for limiting the output power of the RF power amplifier at the amplitude control node, and the first limiting branch adjusts the signal at the amplitude control node according to the first adjustment signal, so that the RF power supply mainly performs closed-loop control based on the target incident power.

[0047] When a change in load impedance causes an increase in actual reflected power, and the reflected power represented by the second feedback signal is greater than or equal to the reflected power limit, the second feedback signal satisfies the reflection limiting condition. The second limiting branch clamps the signal at the amplitude control node according to the second adjustment signal, thus limiting the output power control amount of the RF power amplifier corresponding to the amplitude control signal. Therefore, even if the first adjustment branch tends to increase the output power of the RF power amplifier due to the actual incident power being lower than the target incident power, the second limiting branch can still constrain the amplitude control signal based on the current reflected power state, preventing the RF power amplifier from continuing to maintain or increase to an output power level unfavorable to the reflection power limit.

[0048] Using the reflected power limit value as both the control target represented by the second given signal and the criterion for judging the reflection limiting condition allows the continuous analog adjustment process of the second adjustment branch and the clamping process of the cross-limiting circuit to be coordinated around the same reflected power reference. As the actual reflected power approaches the reflected power limit value, the second adjustment signal can continuously change with the deviation between the two. When the actual reflected power reaches or exceeds the reflected power limit value, the second limiting branch clamps based on the corresponding second adjustment signal. This helps reduce the possibility of abrupt changes in the amplitude control signal when the reflected power limit is intervened, and improves the timeliness and accuracy of the reflected power limit.

[0049] In summary, by using the first given signal to characterize the target incident power, the first adjustment branch can stably adjust the output power of the RF power amplifier according to the deviation between the target incident power and the actual incident power. By using the second given signal to characterize the reflected power limit value, and using the actual reflected power being greater than or equal to the reflected power limit value as the reflection limiting condition, the switching reference between normal incident power control and reflected power limitation can be clearly defined. This allows the RF power supply to operate according to the target incident power when the reflected power is within the allowable range, and to limit the output power of the RF power amplifier in a timely manner when the reflected power reaches the limit level, thereby improving the operational safety of the RF power supply under load mismatch conditions.

[0050] It should be noted that the first feedback signal and the second feedback signal can be power feedback signals that directly characterize the incident power and reflected power, respectively, or they can be incident voltage feedback signals and reflected voltage feedback signals that have a preset mapping relationship with the incident power and reflected power, respectively. For example, the amplitudes of the incident voltage feedback signal and reflected voltage feedback signal formed after detection processing can have a monotonic correspondence or a preset conversion relationship with the corresponding incident power and reflected power, respectively, and thus can be used to characterize the corresponding power. Accordingly, combined with Figure 2 and Figure 3 As shown, Figure 2The incident voltage setpoint signal Pg-F, the first feedback signal RF-F, the reflected voltage setpoint signal Pg-R, and the second feedback signal RF-R are included. Figure 3 The differential components and single-ended signals corresponding to the first and second feedback signals can all be understood as analog voltage signals with a preset mapping relationship to the target incident power, actual incident power, reflected power limit value, and actual reflected power.

[0051] Optionally, the first adjustment branch includes a first error comparison circuit and a first proportional-integral adjustment circuit. The first error comparison circuit is used to generate a first deviation signal based on a first given signal and a first feedback signal, and the first proportional-integral adjustment circuit is used to generate a first adjustment signal based on the first deviation signal.

[0052] In this embodiment, the first adjustment branch includes a first error comparison circuit and a first proportional-integral (PI) adjustment circuit. The first error comparison circuit receives a first given signal and a first feedback signal, respectively, and compares the first given signal and the first feedback signal to generate a first deviation signal that characterizes the deviation between the target incident power and the actual incident power. The magnitude of the first deviation signal reflects the degree of deviation between the target incident power and the actual incident power, and the signal magnitude and / or polarity of the first deviation signal reflects the direction of deviation of the actual incident power relative to the target incident power. The specific input method and input polarity of the first given signal and the first feedback signal in the first error comparison circuit can be set according to the control logic of the first adjustment branch, the first limiting branch, and the RF power amplifier, so that the first adjustment branch forms a negative feedback adjustment to reduce the deviation between the target incident power and the actual incident power.

[0053] The first proportional-integral (PI) control circuit receives a first deviation signal and generates a first control signal based on the current magnitude of the first deviation signal and its accumulation over time. The proportional control function generates a proportional adjustment amount based on the current first deviation signal, enabling the first control signal to respond promptly to changes in the actual incident power. The integral control function generates a corresponding integral adjustment amount based on the accumulation of the first deviation signal over time, ensuring that the first control signal continues to change as the first deviation signal persists, thereby reducing the steady-state deviation that might exist when only proportional control is used. The proportional and integral adjustment amounts are used together to determine the first control signal, enabling the first control branch to balance dynamic response to changes in incident power with steady-state tracking capability of the target incident power.

[0054] For example, when the actual incident power is lower than the target incident power, the first error comparison circuit generates a first deviation signal characterizing the direction and degree of the corresponding deviation based on the first given signal and the first feedback signal. The first proportional-integral (PI) control circuit generates a first adjustment signal based on the first deviation signal to adjust the output power of the RF power amplifier in the direction of reducing the deviation, for example, adjusting the output power of the RF power amplifier in the direction of increasing the deviation. As the actual incident power gradually approaches the target incident power, the first deviation signal decreases accordingly, and the proportional adjustment effect decreases accordingly. The integral adjustment effect continues to adjust the first adjustment signal based on the accumulation of the first deviation signal, so that the actual incident power approaches and stabilizes at the target incident power. Similarly, when the actual incident power is higher than the target incident power, the first PPI control circuit can generate a first adjustment signal to adjust the output power of the RF power amplifier in the direction of decreasing the deviation between the first given signal and the first feedback signal. It should be noted that the specific magnitude, polarity, and direction of change of the first adjustment signal can be determined according to the control logic of the RF power amplifier and its pre-stage control circuit. This embodiment does not impose specific limitations on this.

[0055] Optionally, the second adjustment branch includes a second error comparison circuit and a second proportional-integral adjustment circuit. The second error comparison circuit is used to generate a second deviation signal based on a second given signal and a second feedback signal, and the second proportional-integral adjustment circuit is used to generate a second adjustment signal based on the second deviation signal.

[0056] In this embodiment, the second adjustment branch includes a second error comparison circuit and a second proportional-integral (PI) adjustment circuit. The second error comparison circuit receives a second given signal and a second feedback signal, respectively, and compares the second given signal and the second feedback signal to generate a second deviation signal that characterizes the deviation of the actual reflected power from the reflected power limit value. The magnitude of the second deviation signal reflects the degree of deviation between the actual reflected power and the reflected power limit value, and the signal magnitude and / or polarity of the second deviation signal reflects the direction of deviation of the actual reflected power from the reflected power limit value. The specific input method and input polarity of the second given signal and the second feedback signal in the second error comparison circuit can be set according to the control logic of the second adjustment branch, the second limiting branch, and the RF power amplifier, so that the second adjustment signal generated by the second adjustment branch can be used to constrain the output power of the RF power amplifier when the reflected power reaches the corresponding limit state.

[0057] The second proportional-integral (PI) control circuit receives the second deviation signal and generates a second control signal based on the current magnitude of the second deviation signal and its accumulation over time. The proportional control function generates a proportional adjustment amount based on the current second deviation signal, enabling the second control signal to respond promptly to changes in actual reflected power. The integral control function generates a corresponding integral adjustment amount based on the accumulated second deviation signal over time, allowing the second control signal to adjust according to the continuous deviation of the actual reflected power from the reflected power limit. The proportional and integral adjustment amounts are used together to determine the second control signal, enabling the second control branch to generate a continuous analog control result based on the reflected power deviation while maintaining a fast response speed to changes in reflected power.

[0058] For example, when the load impedance changes and the actual reflected power gradually increases, the second feedback signal changes accordingly. The second error comparison circuit generates a corresponding second deviation signal based on the second given signal and the second feedback signal. The second proportional-integral adjustment circuit then adjusts the second adjustment signal based on the second deviation signal. When the actual reflected power is less than the reflected power limit and the second feedback signal does not meet the reflection limiting condition, the second limiting branch does not effectively clamp the signal at the amplitude control node to limit the RF power amplifier output power. The first limiting branch can adjust the signal at the amplitude control node according to the first adjustment signal. When the actual reflected power is greater than or equal to the reflected power limit and the second feedback signal meets the reflection limiting condition, the second limiting branch clamps the signal at the amplitude control node according to the second adjustment signal currently generated by the second proportional-integral adjustment circuit, thereby limiting the RF power amplifier output power control amount corresponding to the amplitude control signal.

[0059] After the second limiting branch clamps the signal, the output power of the RF power amplifier is limited, and the actual reflected power can change accordingly. The sampling unit updates the second feedback signal based on the output signal of the RF power supply. The second error comparison circuit generates a new second deviation signal based on the updated second feedback signal, and the second proportional-integral adjustment circuit adjusts the second adjustment signal based on the new second deviation signal, thus forming a continuous-time analog adjustment process with the actual reflected power as feedback. Through this process, the second adjustment signal can change with the deviation of the actual reflected power from the reflected power limit value. The second limiting branch clamps the signal at the amplitude control node accordingly, so that the reflected power limiting effect can adapt to the current reflected power state, which is beneficial to improving the timeliness, continuity and stability of the reflected power limiting response.

[0060] It should be noted that in different embodiments, both the first and second adjustment branches can employ error comparison circuits and proportional-integral (PI) control circuits, or only the first or second adjustment branch can employ the above circuit structure. When the first adjustment branch employs a first error comparison circuit and a first PI control circuit, a PI control result can be generated based on the deviation between the target incident power and the actual incident power, which is beneficial for improving the dynamic response capability and steady-state tracking accuracy of the incident power closed-loop control. When the second adjustment branch employs a second error comparison circuit and a second PI control circuit, a continuous second adjustment signal can be generated based on the deviation between the actual reflected power and the reflected power limit value, which is beneficial for improving the response timeliness and adjustment stability of the reflected power limit. When both the first and second adjustment branches employ the above circuit structure, the two adjustment branches can generate continuous PI control results based on the incident power deviation and the reflected power deviation, respectively, and act together on the amplitude control node through a cross-limiting circuit.

[0061] In summary, by generating a deviation signal based on the given and feedback signals using an error comparison circuit, and generating a corresponding adjustment signal based on the deviation signal using a proportional-integral (PI) control circuit, the system can respond promptly to power state changes using proportional control and reduce persistent power control deviations using integral control. Specifically, the first error comparison circuit and the first PI control circuit improve the dynamic response capability and steady-state tracking accuracy of the incident power closed-loop control. The second error comparison circuit and the second PI control circuit enable the second adjustment signal to continuously change with the deviation of the actual reflected power from the reflected power limit value, thus improving the timeliness of the reflected power limit response and the stability of the adjustment. When both the first and second adjustment branches adopt the above circuit structure, the two adjustment branches can generate continuous PI control results, which are then coordinated and applied to the amplitude control node through a cross-limiting circuit. This helps reduce the possibility of fluctuations in the RF power amplifier output power or loop oscillations during the switching process between incident power control and reflected power limit.

[0062] Optionally, the first proportional-integral (PI) control circuit and the second PI control circuit each include an operational amplifier and a resistor-capacitor network connected to the corresponding operational amplifier; the proportional coefficient of the first PI control circuit is matched with the proportional coefficient of the second PI control circuit, and / or the integral time constant of the first PI control circuit is matched with the integral time constant of the second PI control circuit, so that the first control branch and the second control branch have matched dynamic response characteristics.

[0063] In this embodiment, both the first proportional-integral (PI) control circuit and the second PI control circuit are analog PI control circuits. The first PI control circuit includes a corresponding operational amplifier and a resistor-capacitor network connected to the operational amplifier, and the second PI control circuit includes a corresponding operational amplifier and a resistor-capacitor network connected to the operational amplifier. Each operational amplifier is used to amplify and process the corresponding deviation signal, and each resistor-capacitor network is used to form proportional and integral control actions in the corresponding PI control circuit, enabling the first PI control circuit and the second PI control circuit to generate a first control signal and a second control signal respectively in the continuous time domain.

[0064] Specifically, the resistor-capacitor network can be connected to the input side, feedback side, or both of the corresponding operational amplifier to determine the signal gain and time response characteristics of the proportional-integral (PI) control circuit. The proportionality coefficient characterizes the degree to which the corresponding PI control circuit applies adjustment based on the current deviation signal, and the integral time constant characterizes how quickly the PI control circuit accumulates and adjusts the deviation signal over time. By configuring the resistance values, the resistance relationships between different resistors, the capacitance of the capacitors, and the connection relationships between resistors and capacitors in the resistor-capacitor network, the proportionality coefficient and integral time constant of the corresponding PI control circuit can be set. The first and second PI control circuits can use the same or different resistor-capacitor network topologies, as long as they can respectively achieve the corresponding PI control functions.

[0065] Matching the proportional coefficients of the first and second proportional-integral (PI) control circuits means coordinating the two proportional coefficients based on the signal ranges and gain relationships of the corresponding given signals, feedback signals, and deviation signals in the first and second control branches. This ensures that both the first and second control signals respond to the corresponding deviation signals with a degree of change appropriate to the power deviation. For example, it prevents one control branch from having a significantly stronger proportional control effect than the other, which could lead to excessively rapid or slow changes in the corresponding control signals. It should be noted that matching the two proportional coefficients does not require their values ​​to be exactly the same. When the first and second feedback signals have different ranges, conversion ratios, or signal gains, two separate proportional coefficients can be configured to compensate for differences in the corresponding signal processing links, enabling the first and second control branches to achieve coordinated proportional control responses.

[0066] Similarly, matching the integral time constants of the first and second proportional-integral (PI) control circuits means coordinating the two integral time constants according to the response requirements of the incident power control process and the reflected power limiting process, so that the first and second control signals have a coordinated rate of change in response to the continuous accumulation of the corresponding deviation signals. Matching the two integral time constants does not require them to be exactly equal; rather, they can be determined by considering the feedback gain, signal range, response speed, and operating characteristics of the cross-limiting circuit for each of the two control branches. For example, by configuring the corresponding resistance and capacitance values ​​in the first and second PI control circuits, the two control branches can have similar or coordinated integral accumulation rates when the corresponding deviation signals change, avoiding either one control branch having an excessively fast integral action leading to rapid accumulation of the control amount, or an integral action that is too slow to keep up with changes in the power state.

[0067] The matched dynamic response characteristics in this embodiment may include matching at least one of the following: response speed, regulation bandwidth, rise time, settling time, overshoot characteristics, and tracking characteristics to changes in the corresponding deviation signal of the first and second regulation branches. Matching does not mean that all dynamic response parameters of the two regulation branches are the same, but rather that the dynamic response relationship of the two regulation branches can meet the requirements of cross-amplitude limiting control, so that when the first and second regulation signals act on the same amplitude control node, the continuity of the amplitude control signal will not be significantly affected by an excessively large difference in response speed between the two regulation branches.

[0068] For example, when the second feedback signal does not meet the reflection limiting condition, the first limiting branch adjusts the signal at the amplitude control node according to the first adjustment signal, and the first proportional-integral (PI) control circuit continuously adjusts the first adjustment signal according to the incident power deviation. As the load impedance changes, the actual reflected power gradually increases, and the second PI control circuit continuously adjusts the second adjustment signal according to the reflected power deviation. When the second feedback signal meets the reflection limiting condition, the second limiting branch clamps the signal at the amplitude control node according to the second adjustment signal. Since the proportional coefficients and / or integral time constants of the first and second PI control circuits are coordinated, the second adjustment signal can coordinate with the original adjustment state formed by the first adjustment signal at the amplitude control node when participating in clamping, thereby helping to reduce the abrupt change in the amplitude control signal during the intervention of the second limiting branch.

[0069] When the reflected power decreases and the second feedback signal no longer meets the reflection limiting condition, the second limiting branch releases or weakens its clamping effect on the signal at the amplitude control node, and the first limiting branch readjusts the signal at the amplitude control node according to the first adjustment signal. The two adjustment branches have matched dynamic response characteristics, which helps to maintain a coordinated trend in the change of the first and second adjustment signals during the entry and exit of the reflection limiting state, avoiding large fluctuations in the signal at the amplitude control node caused by one adjustment branch responding too quickly and the other too slowly.

[0070] The proportional gain and integral time constant can be determined based on the target output power range of the RF power supply, the reflected power limitation requirements, the feedback gain of the sampling unit, the power response characteristics of the RF power amplifier, and the operating characteristics of the cross-limiting circuit. For example, the proportional gain and integral time constant of the first proportional-integral (PI) regulating circuit can be determined first based on the response requirements of the incident power closed-loop control. Then, the proportional gain and integral time constant of the second PI regulating circuit can be determined by combining the variation range of the second feedback signal and the response speed required for the reflected power limitation. Alternatively, the two regulating branches can be jointly debugged to ensure that the response speed, settling time, or trend of the regulating signal under preset power variation conditions meets the preset matching requirements.

[0071] It should be noted that matching configuration can be performed on only the two proportional coefficients, only the two integral time constants, or both proportional coefficients and integral time constants simultaneously. When only the proportional coefficients are matched, the primary function is to coordinate the response strength of the two control branches to the current deviation signal. When only the integral time constants are matched, the primary function is to coordinate the cumulative adjustment speed of the two control branches to the sustained deviation. When both proportional coefficients and integral time constants are matched, the transient response and continuous adjustment process of the two control branches can be further coordinated.

[0072] In summary, by constructing a first proportional-integral (PI) control circuit and a second PI control circuit using an operational amplifier and its connected resistor-capacitor network, proportional-integral (PI) control of the incident power deviation and reflected power deviation can be performed separately in a continuous-time analog manner. By coordinating the proportional coefficients and / or integral time constants of the two PI control circuits, the first and second control branches can have matched dynamic response characteristics. This helps to maintain a coordinated control process when the two control branches work together on the amplitude control node, reducing the possibility of abrupt changes in the amplitude control signal, fluctuations in the RF power amplifier output power, or loop oscillations when the reflected power limit is engaged or disengaged, and improving the continuity and smoothness of the switching between incident power control and reflected power limit.

[0073] Optionally, the first limiting branch includes a first transistor limiting circuit and a first cross-limiting diode, and the second limiting branch includes a second transistor limiting circuit and a second cross-limiting diode; The anode of the first cross-limiting diode is connected to the output terminal of the first transistor limiting circuit, and the cathode of the first cross-limiting diode is connected to the output terminal of the second proportional-integral adjustment circuit. The anode of the second cross-limiting diode is connected to the output terminal of the second transistor limiting circuit, and the cathode of the second cross-limiting diode is connected to the output terminal of the first proportional-integral adjustment circuit.

[0074] In this embodiment, the first transistor limiting circuit is used to form a first limiting output signal based on the first adjustment signal generated by the first proportional-integral (PI) adjustment circuit, and the second transistor limiting circuit is used to form a second limiting output signal based on the second adjustment signal generated by the second PI adjustment circuit. Both the first and second transistor limiting circuits can include at least one transistor and peripheral circuitry connected to the transistor. By changing the transistor's conduction state, they can perform level conversion, limiting processing, or drive capability adjustment on the adjustment signals generated by the corresponding PI adjustment circuits. The specific type, number, and connection method of the transistors can be set according to the signal polarity and amplitude range of the first and second adjustment signals, as well as the control logic of the cross-limiting circuit.

[0075] A first cross-limiting diode is connected between the output of the first transistor limiting circuit and the output of the second proportional-integral (PI) control circuit. The anode of the first cross-limiting diode is connected to the output of the first transistor limiting circuit, and the cathode is connected to the output of the second PI control circuit. When the potential relationship between the outputs of the first transistor limiting circuit and the second PI control circuit satisfies the forward conduction condition of the first cross-limiting diode, the first cross-limiting diode conducts, thus establishing a unidirectional signal transmission path between them, allowing the first limiting branch to constrain the output state of the second PI control circuit. When the potential relationship does not satisfy the forward conduction condition of the first cross-limiting diode, the first cross-limiting diode is cut off or substantially cut off, reducing the influence of the first limiting branch on the output of the second PI control circuit.

[0076] The second cross-limiting diode is connected between the output of the second transistor limiting circuit and the output of the first proportional-integral (PI) regulating circuit. The anode of the second cross-limiting diode is connected to the output of the second transistor limiting circuit, and the cathode is connected to the output of the first PI regulating circuit. When the potential relationship between the outputs of the second transistor limiting circuit and the first PI regulating circuit satisfies the forward conduction condition of the second cross-limiting diode, the second cross-limiting diode conducts, thus establishing a unidirectional signal transmission path between them, allowing the second limiting branch to constrain the output state of the first PI regulating circuit. When the potential relationship does not satisfy the forward conduction condition of the second cross-limiting diode, the second cross-limiting diode is cut off or substantially cut off, reducing the influence of the second limiting branch on the output of the first PI regulating circuit.

[0077] Thus, the first and second cross-limiting diodes form two cross-limiting paths with opposite directions, enabling the first and second regulation branches to mutually constrain each other according to their respective regulation signals' output states. Because diodes have unidirectional conduction characteristics, the two regulation branches are not directly and rigidly connected, but rather selectively establish signal transmission paths based on the potential relationship between corresponding nodes. This allows for cross-limiting while reducing unnecessary influence of one regulation branch on the normal regulation process of the other.

[0078] When the second feedback signal does not meet the reflection limiting condition, the operating states of each transistor limiting circuit and the cross-limiting diode in the cross-limiting circuit are configured such that the second limiting branch does not form an effective clamp to the output terminal of the first proportional-integral adjustment circuit for limiting the output power of the RF power amplifier. At this time, the first adjustment signal generated by the first proportional-integral adjustment circuit can adjust the signal at the amplitude control node through the first limiting branch, so that the RF power supply mainly performs closed-loop adjustment based on the deviation between the target incident power and the actual incident power.

[0079] When the actual reflected power increases to the point that the second feedback signal meets the reflection limiting condition, the second adjustment signal generated by the second proportional-integral (PI) control circuit changes with the reflected power deviation, and the second transistor limiting circuit correspondingly changes the signal state at its output. When the potential relationship across the second cross-limiting diode meets its forward conduction condition, the second cross-limiting diode conducts, allowing the second transistor limiting circuit to impose a corresponding constraint on the output of the first PI control circuit through the second cross-limiting diode. Thus, the first adjustment signal can be limited from continuing to maintain or change the signal at the amplitude control node to a control level unfavorable to the reflected power limitation, enabling the second limiting branch to constrain the power increase trend corresponding to the first adjustment branch when the reflected power reaches the limit state.

[0080] During the limiting process of the second limiting branch, the first cross-limiting diode can also be turned on or off according to the potential relationship between the output terminal of the first transistor limiting circuit and the output terminal of the second proportional-integral adjustment circuit, thereby maintaining a corresponding cross-constraint relationship between the first and second limiting branches. The specific conduction states and state combinations of the first and second cross-limiting diodes can be determined based on the signal polarity and circuit parameters of the two adjustment branches, as long as the first adjustment branch can adjust the incident power when the reflected power does not reach the limit condition, and the second adjustment branch can form a corresponding limiting constraint on the first adjustment branch when the reflected power reaches the limit condition.

[0081] When the load condition recovers and the actual reflected power decreases, causing the second feedback signal to no longer meet the reflection limiting condition, the output states of the second proportional-integral (PI) regulating circuit and the second transistor limiting circuit change accordingly. This releases or weakens the constraint effect of the second cross-limiting diode on the output of the first PI regulating circuit. The first PI regulating circuit can then regenerate the first regulating signal based on the deviation between the first given signal and the first feedback signal, allowing the first regulating branch to resume its dominant regulation of the signal at the amplitude control node.

[0082] In summary, by connecting the first cross-limiting diode between the output of the first transistor limiting circuit and the output of the second proportional-integral (PI) regulating circuit, and connecting the second cross-limiting diode between the output of the second transistor limiting circuit and the output of the first PI regulating circuit, two intersecting limiting paths with unidirectional transmission characteristics can be formed. The two cross-limiting diodes can automatically turn on or off according to the potential relationship between their respective nodes, enabling the first and second regulating branches to form corresponding regulating constraints under different reflected power states. This facilitates timely limitation of the RF power amplifier output power under load mismatch conditions and reduces the possibility of sudden changes in the amplitude control signal, fluctuations in the RF power amplifier output power, or loop regulation oscillations during the switching process between incident power regulation and reflected power limitation.

[0083] For example, combined Figure 3 As shown, the analog control unit 140 may include an incident voltage signal conditioning unit 131, a reflected voltage signal conditioning unit 132, a dual-loop cross-limiting and proportional-integral adjustment unit 133, a PI regulator limiting unit 134, and a loop control signal proportional unit 135. Figure 3 It shows Figure 2 A specific circuit structure of the analog control unit 140, wherein, Figure 2 101 to 107 are functional modules divided according to control functions. Figure 3131 to 135 in the diagram represent the circuit functional regions divided according to the specific circuit structure.

[0084] The incident voltage signal conditioning unit 131 may include a first differential receiving circuit for converting the differential form of the first feedback signal into a first single-ended feedback signal; the reflected voltage signal conditioning unit 132 may include a second differential receiving circuit for converting the differential form of the second feedback signal into a second single-ended feedback signal. The first single-ended feedback signal and the second single-ended feedback signal are respectively provided to the dual-loop cross-limiting and proportional-integral adjustment unit 133.

[0085] In the dual-loop cross-limiting and proportional-integral adjustment unit 133, the operational amplifier U2A and its input and feedback side resistor-capacitor networks can jointly realize the corresponding functions of the first error comparison circuit and the first proportional-integral adjustment circuit. The first error comparison circuit generates a first deviation signal based on the first given signal and the first single-ended feedback signal, and the first proportional-integral adjustment circuit generates a first adjustment signal based on the first deviation signal.

[0086] Operational amplifier U3B and its input and feedback resistor-capacitor networks together realize the corresponding functions of the second error comparator circuit and the second proportional-integral (PI) control circuit. The second error comparator circuit generates a second deviation signal based on the second given signal and the second single-ended feedback signal, and the second PI control circuit generates a second adjustment signal based on the second deviation signal.

[0087] Transistors QP1 and QP2, along with their peripheral circuitry, can constitute a first transistor limiting circuit. Transistors QP3 and QP4, along with their peripheral circuitry, can constitute a second transistor limiting circuit. Diode D1 can serve as a first cross-limiting diode, and diode D2 can serve as a second cross-limiting diode. The first transistor limiting circuit and the first cross-limiting diode can together constitute at least a portion of the first limiting branch, and the second transistor limiting circuit and the second cross-limiting diode can together constitute at least a portion of the second limiting branch.

[0088] The anode of diode D1 is connected to the output terminal of the first transistor limiting circuit, and the cathode of diode D1 is connected to the output terminal of the second proportional-integral adjustment circuit; the anode of diode D2 is connected to the output terminal of the second transistor limiting circuit, and the cathode of diode D2 is connected to the output terminal of the first proportional-integral adjustment circuit, thereby forming a cross-limiting relationship between the first limiting branch and the second limiting branch.

[0089] Resistor R32 can be used as the first bypass resistor, connected in parallel across diode D1; resistor R53 can be used as the second bypass resistor, connected in parallel across diode D2. Operational amplifier U4A in the PI regulator limiting unit 134 can be used as a compensation operational amplifier to proportionally condition and level-shift the corresponding limiting signal, compensating for the voltage difference generated during the conduction of the corresponding transistor limiting circuit.

[0090] The node where the first and second limiting branches are connected and function together can be used as an amplitude control node. The loop control signal scaling unit 135 may include an operational amplifier U1B and a resistor-capacitor network connected to the operational amplifier U1B, used to scale, level-shift, bias-adjust, or impedance-transform the signal at the amplitude control node, and output an amplitude control signal marked DDS-REF via resistor R23.

[0091] The DDS-REF is a continuously varying analog voltage signal used as an amplitude control reference for the signal modulation unit 108 to adjust the amplitude of the radio frequency reference signal. The DDS-REF is not used to transmit digital control data, nor is it used to provide a clock reference for the DDS.

[0092] Figure 3 The units, devices, and connections shown are only one specific implementation of the analog control unit 140 and are not intended to limit the specific circuit configuration of the first differential receiving circuit, the second differential receiving circuit, the first error comparison circuit, the second error comparison circuit, the first proportional-integral adjustment circuit, the second proportional-integral adjustment circuit, the first limiting branch, the second limiting branch, the limiting compensation unit, and the loop control signal conditioning unit.

[0093] Optionally, a first bypass resistor is connected in parallel across the two ends of the first cross-limiting diode, and a second bypass resistor is connected in parallel across the two ends of the second cross-limiting diode.

[0094] In this embodiment, the first bypass resistor is connected in parallel with the first cross-limiting diode, thus connecting together with the first cross-limiting diode between the output terminal of the first transistor limiting circuit and the output terminal of the second proportional-integral adjustment circuit; the second bypass resistor is connected in parallel with the second cross-limiting diode, thus connecting together with the second cross-limiting diode between the output terminal of the second transistor limiting circuit and the output terminal of the first proportional-integral adjustment circuit. The first bypass resistor and the second bypass resistor are respectively used to form resistive coupling paths across the corresponding cross-limiting diodes.

[0095] Specifically, the cross-limiting diode selectively conducts or cuts off based on the potential relationship between its anode and cathode. When the first cross-limiting diode meets the forward conduction condition, it forms a low-impedance unidirectional signal transmission path between the output of the first transistor limiting circuit and the output of the second proportional-integral (PI) regulating circuit, enabling the first limiting branch to constrain the output state of the second PI regulating circuit. When the first cross-limiting diode does not meet the forward conduction condition, it is cut off or substantially cut off. The first bypass resistor still provides a relatively high-impedance resistive coupling path across the first cross-limiting diode, preventing complete isolation between the output of the first transistor limiting circuit and the output of the second PI regulating circuit.

[0096] Similarly, when the second cross-limiting diode meets the forward conduction condition, it forms a low-impedance unidirectional signal transmission path between the output of the second transistor limiting circuit and the output of the first proportional-integral regulation circuit, enabling the second limiting branch to constrain the output state of the first proportional-integral regulation circuit. When the second cross-limiting diode does not meet the forward conduction condition, the second bypass resistor provides a relatively high-impedance resistive coupling path across the second cross-limiting diode, thus limiting the mutual influence between the two nodes while maintaining a certain signal correlation between them.

[0097] Therefore, when the corresponding cross-limiting diode is conducting, the cross-limiting effect is mainly achieved through the conducting cross-limiting diode; when the corresponding cross-limiting diode is cut off, the bypass resistor provides a restricted resistive signal transmission path. Since the value of the bypass resistor can be set to be greater than the equivalent impedance of the corresponding cross-limiting diode when it is forward conducting, the bypass resistor usually does not change the limiting relationship dominated by the cross-limiting diode when the cross-limiting diode is conducting; when the cross-limiting diode is cut off, the bypass resistor can also prevent the two corresponding nodes from being completely disconnected.

[0098] When the second feedback signal does not meet the reflection limiting condition, the first adjustment branch mainly adjusts the signal at the amplitude control node based on the incident power deviation, and the second limiting branch does not effectively clamp the output of the first proportional-integral adjustment circuit. At this time, the second bypass resistor can form resistive coupling between the output of the second transistor limiting circuit and the output of the first proportional-integral adjustment circuit, allowing the potential change at the corresponding node of the second limiting branch to act on the first adjustment branch to a limited extent, while preventing the effect from being strong enough to affect the normal implementation of incident power closed-loop regulation by the first adjustment branch.

[0099] When the actual reflected power increases and the second feedback signal meets the reflection limiting condition, the output states of the second proportional-integral (PI) regulating circuit and the second transistor limiting circuit change accordingly. When the second cross-limiting diode meets the forward conduction condition, it forms a cross-limiting path with relatively low impedance, enabling the second limiting branch to impose a corresponding constraint on the output of the first PI regulating circuit. Since the second bypass resistor already provides resistive coupling between the two corresponding nodes before the second cross-limiting diode turns on, it helps to reduce the abrupt change in the potential relationship of the corresponding nodes when the second cross-limiting diode switches from the off state to the on state.

[0100] When the reflected power decreases and the second feedback signal no longer meets the reflection limiting condition, the second cross-limiting diode changes from the conducting state to the cutting state, and the clamping effect of the second limiting branch on the output of the first proportional-integral regulation circuit is correspondingly released or weakened. At this time, the second bypass resistor can still provide a resistive path between the two corresponding nodes, allowing the potential difference between the two nodes to be gradually adjusted through this resistive path, and can provide a release path for the charge accumulated on the corresponding nodes, thereby helping to reduce the possibility of a sudden change in the signal at the output of the first proportional-integral regulation circuit when the second cross-limiting diode exits limiting. The first bypass resistor can play a similar role during the change of the conducting state of the first cross-limiting diode.

[0101] The values ​​of the first and second bypass resistors can be configured based on the output impedances of the first and second proportional-integral (PI) control circuits, the output characteristics of the two transistor limiting circuits, the conduction characteristics of the cross-limiting diode, and the required degree of cross-coupling. A smaller bypass resistor value results in stronger resistive coupling between the two nodes; a larger bypass resistor value results in weaker resistive coupling. By appropriately setting the values ​​of the first and second bypass resistors, unnecessary mutual interference between the two control branches can be reduced while maintaining the limiting effect of the cross-limiting diode, and the entry and exit of the cross-limiting state can be made more continuous.

[0102] For example, combined Figure 3 As shown, the first cross-limiting diode can be diode D1, and the first bypass resistor can be resistor R32 connected in parallel with diode D1; the second cross-limiting diode can be diode D2, and the second bypass resistor can be resistor R53 connected in parallel with diode D2. Resistors R32 and R53 provide resistive coupling paths when the corresponding diodes are off, and buffer the potential changes of the relevant nodes when the corresponding diodes switch between on and off states. Figure 3 The devices and connection methods shown are merely examples and are not intended to limit the specific resistance values ​​and device forms of the first and second bypass resistors.

[0103] In summary, by connecting a first bypass resistor and a second bypass resistor in parallel across the first and second cross-limiting diodes, respectively, the cross-limiting diodes can form the main limiting path when they are conducting, and maintain limited resistive coupling through the bypass resistors when they are turned off. This helps avoid complete isolation of the relevant nodes of the two regulation branches when the cross-limiting diodes are turned off, mitigates node potential changes caused by changes in the conduction state of the cross-limiting diodes, and thus reduces the possibility of abrupt changes in the amplitude control signal, fluctuations in the RF power amplifier output power, or loop regulation oscillations during the intervention or withdrawal of reflected power limiting.

[0104] For example, the first transistor limiting circuit and the second transistor limiting circuit may each include at least one PNP transistor. The PNP transistor can change its conduction state according to the adjustment signal output by the corresponding proportional-integral adjustment circuit, and cooperate with the external resistor to form a corresponding limiting output signal. By using PNP transistors, the level conversion, limiting, or drive capability adjustment of the corresponding adjustment signal can be performed according to the signal polarity of the corresponding node, so as to meet the conduction control requirements of the first cross-limiting diode and the second cross-limiting diode.

[0105] For example, combining Figure 3 As shown, the first transistor limiting circuit may include PNP transistors QP1 and QP2, and the second transistor limiting circuit may include PNP transistors QP3 and QP4. Each PNP transistor, in conjunction with a corresponding external resistor, generates a corresponding limiting output signal based on either the first or second adjustment signal. Figure 3 The number of transistors and the specific connection method shown are only one example; in other embodiments, the first transistor limiting circuit and the second transistor limiting circuit may also include one PNP transistor, three or more PNP transistors, or other types of transistors that can achieve the corresponding limiting function.

[0106] For example, the first and second cross-limiting diodes can be silicon switching diodes, Schottky diodes, or other diodes with unidirectional conduction characteristics. Silicon switching diodes have the characteristics of fast switching speed and low reverse leakage current, making them suitable for forming a stable cross-limiting path; Schottky diodes have the characteristics of low forward voltage drop and short reverse recovery time, enabling them to establish a cross-limiting path when the potential difference between corresponding nodes is small, which helps to improve the response time of the cross-limiting effect.

[0107] The first and second cross-limiting diodes can be of the same type, or different types of diodes can be used depending on the requirements of the forward voltage, response speed, and leakage current of the two cross-limiting paths. For example, both the first and second cross-limiting diodes can be silicon switching diodes, both can be Schottky diodes, or one can be a silicon switching diode and the other a Schottky diode. The specific device type can be selected based on the signal amplitude, signal polarity, and required cross-limiting threshold of the first and second regulating branches.

[0108] Combination Figure 3 As shown, diodes D1 and D2 can be small-signal switching diodes to quickly turn on or off according to the potential relationship between the corresponding nodes. In other embodiments, at least one of diodes D1 and D2 can be replaced with a Schottky diode to reduce the forward voltage drop of the corresponding cross-limiting path. It should be noted that the specific type of diode does not change the basic connection relationship and cross-limiting principle of the first and second cross-limiting diodes.

[0109] In summary, using PNP transistors to construct the first and second transistor limiting circuits can provide limiting outputs that are compatible with the adjustment signal for the corresponding cross-limiting paths. By selecting silicon switching diodes or Schottky diodes according to actual control requirements, the performance of on-state voltage drop, response speed, and leakage current can be configured, thereby improving the adaptability of the cross-limiting circuit to different signal ranges and dynamic response requirements.

[0110] Optionally, the RF power supply sampling and control circuit further includes a limiting compensation unit, which is connected to the cross-limiting circuit and is used to compensate for the on-state voltage drop of at least one of the first limiting branch and the second limiting branch.

[0111] In this embodiment, the transistors and diodes in the first and second limiting branches generate corresponding on-state voltage drops during conduction, which may cause a deviation between the actual limiting output and the target limiting value. The limiting compensation unit is used to perform at least one of proportional conditioning and level offset on the limiting signal of the corresponding limiting branch to compensate for the voltage difference generated by the corresponding transistor limiting circuit during conduction, thereby reducing the deviation between the actual limiting value and the target limiting value.

[0112] The limiting compensation unit may include a compensation operational amplifier and a resistor-capacitor network connected to the compensation operational amplifier. The compensation operational amplifier receives the limiting signal from the corresponding limiting branch, generates a compensated limiting control signal based on the limiting signal, and provides the compensated limiting control signal to the corresponding limiting branch. The proportional gain and level offset of the compensation operational amplifier can be set through the resistor-capacitor network connected to it.

[0113] For example, combined Figure 3 As shown, the limiting compensation unit may include a PI regulator limiting unit 134, and the compensation operational amplifier may be an operational amplifier U4A. The operational amplifier U4A performs proportional conditioning and level offset on the limiting signal corresponding to the limiting state to compensate for the voltage difference generated during the conduction of the transistor limiting circuit, so that the actual limiting output maintains a preset correspondence with the target limiting value. Figure 3 The PI regulator limiting unit 134 shown is only one specific implementation of the limiting compensation unit.

[0114] Optionally, the RF power supply sampling and control circuit further includes a loop control signal conditioning unit. The loop control signal conditioning unit is connected between the amplitude control node and the signal modulation unit and is used to perform at least one of the following on the signal at the amplitude control node: proportional adjustment, level conversion, polarity adjustment, bias adjustment, and impedance transformation, so that the processed amplitude control signal meets the input requirements of the signal modulation unit.

[0115] For example, combined Figure 3 As shown, the loop control signal conditioning unit may include a loop control signal scaling unit 135. The loop control signal scaling unit 135 may include an operational amplifier U1B and a resistor-capacitor network connected to the operational amplifier U1B. Based on the input signal range of the analog multiplier and the power adjustment range of the RF power amplifier, it performs scaling, level conversion, bias adjustment, or impedance transformation on the signal at the amplitude control node. The output signal of the operational amplifier U1B can be output via resistor R23 to form... Figure 3 The amplitude control signal is marked as DDS-REF. DDS-REF is a continuously varying analog voltage signal used as an amplitude control reference for the signal modulation unit 108 to adjust the amplitude of the radio frequency reference signal; DDS-REF is not used to transmit digital control data, nor is it used to provide a clock reference for DDS.

[0116] By setting up a loop control signal conditioning unit, the control signal generated by the cross-limiting circuit can be matched with the input range of the subsequent signal modulation unit, and impedance isolation can be performed between the preceding and following circuits, which helps to reduce the impact of subsequent load changes on the operating state of the cross-limiting circuit.

[0117] Optionally, the RF power supply sampling and control circuit further includes a signal modulation unit, which receives an amplitude control signal and an RF reference signal, and adjusts the amplitude of the RF reference signal according to the amplitude control signal to generate an RF control signal for controlling the output power of the RF power amplifier.

[0118] In this embodiment, the radio frequency (RF) reference signal is an RF signal with a preset frequency, which can be generated by an RF signal source, an oscillation circuit, or a frequency synthesis circuit. The amplitude control signal can be an analog control signal output by a cross-limiting circuit, or it can be an analog control signal formed by proportional adjustment, level conversion, or impedance transformation of the signal output by the cross-limiting circuit through a loop control signal conditioning unit. It is used to characterize the output power control amount required by the RF power amplifier. The signal modulation unit receives the RF reference signal and the amplitude control signal respectively, and determines the amplitude adjustment amount of the RF reference signal according to the amplitude control signal.

[0119] Specifically, the signal modulation unit can proportionally attenuate, proportionally amplify, or adjust the gain of the RF reference signal according to the amplitude control signal, so that the generated RF control signal maintains the frequency characteristics of the RF reference signal, while its signal amplitude changes with the amplitude control signal. The correspondence between the amplitude control signal and the RF control signal amplitude can be set according to the input and output characteristics of the RF power amplifier, as long as the output power of the RF power amplifier changes in the direction of reducing control deviation with the amplitude control signal.

[0120] When the second feedback signal does not meet the reflection limiting condition, the first adjustment branch mainly generates an amplitude control signal based on the deviation between the target incident power and the actual incident power. The signal modulation unit adjusts the amplitude of the RF control signal accordingly, causing the output power of the RF power amplifier to change towards the power state corresponding to the target incident power.

[0121] When the second feedback signal meets the reflection limiting condition, the second limiting branch clamps the signal at the amplitude control node, thereby limiting the amplitude control signal from changing in a direction unfavorable to reflection power limiting. The signal modulation unit limits the amplitude of the RF control signal based on the clamped amplitude control signal, thereby limiting the output power of the RF power amplifier to reduce the risk of excessive reflection power under load mismatch conditions.

[0122] For example, the signal modulation unit may include an analog multiplier, a variable gain amplifier, or a voltage-controlled attenuator. When using an analog multiplier, the RF reference signal and the amplitude control signal can be input to the two input terminals of the analog multiplier, respectively, so that the analog multiplier outputs an RF control signal whose amplitude varies with the amplitude control signal. The RF control signal can be directly provided to the RF power amplifier, or it can be buffered, filtered, or pre-amplified before being provided to the RF power amplifier.

[0123] By setting up a signal modulation unit, the amplitude control signal generated by the cross-limiting circuit can be converted into an amplitude-adjustable radio frequency control signal, so that the incident power adjustment and reflected power limitation results can be applied to the driving amplitude of the radio frequency power amplifier, which is conducive to forming a closed-loop control link from power sampling, analog adjustment, cross-limiting to radio frequency power output.

[0124] Optionally, the signal modulation unit includes an analog multiplier, the first input of which is used to receive an amplitude control signal, and the second input of which is used to receive a radio frequency reference signal; the analog multiplier is used to perform analog multiplication on the amplitude control signal and the radio frequency reference signal, and outputs the radio frequency control signal through the output of the analog multiplier.

[0125] In this embodiment, the analog multiplier has two input terminals for receiving an amplitude control signal and an RF reference signal, respectively, and performs multiplication on the two input signals in the continuous-time analog signal domain. The amplitude control signal is used to determine the amplitude of the RF control signal, and the RF reference signal is used to provide the frequency and phase reference of the RF control signal.

[0126] Specifically, with the frequency and waveform of the RF reference signal remaining constant, the analog multiplier adjusts the amplitude of the RF control signal accordingly based on changes in the amplitude control signal, establishing a preset correspondence between the amplitude of the RF control signal and the amplitude control signal. This preset correspondence can be set based on the conversion coefficients of the analog multiplier, the amplitude range of the input signal, and the driving requirements of the RF power amplifier.

[0127] When the second feedback signal does not meet the reflection limiting condition, the analog multiplier outputs a corresponding amplitude RF control signal based on the amplitude control signal formed by the first limiting branch, causing the output power of the RF power amplifier to change towards the power state corresponding to the target incident power. When the second feedback signal meets the reflection limiting condition, the second limiting branch clamps the amplitude control signal, and the analog multiplier accordingly limits the amplitude of the RF control signal, thereby limiting the output power of the RF power amplifier.

[0128] For example, the analog multiplier can be a multiplier chip with two analog signal input terminals, and its peripheral components can be configured with input conditioning circuitry, gain configuration circuitry, and output buffer circuitry. The amplitude control signal and the RF reference signal can be provided to the analog multiplier after corresponding input conditioning. The RF control signal output by the analog multiplier can be directly provided to the RF power amplifier, or it can be provided to the RF power amplifier after filtering, buffering, or pre-amplification.

[0129] By employing an analog multiplier, the amplitude control signal output by the cross-limiting circuit can be continuously converted into amplitude changes of the RF control signal, enabling the incident power adjustment result and the reflected power limiting result to be applied to the RF power amplifier in a timely manner, which is beneficial to improving the response speed and stability of the RF power closed-loop regulation.

[0130] Optionally, the RF power supply sampling and control circuit further includes an RF drive conditioning unit, which is connected between the signal modulation unit and the RF power amplifier. The RF drive conditioning unit is used to perform at least one of the following on the RF control signal: buffering, gain adjustment, filtering, waveform shaping and impedance matching, and to provide the processed RF drive signal to the RF power amplifier.

[0131] The RF drive conditioning unit may include at least one of an RF operational amplifier, an RF buffer, a preamplifier, and an impedance matching network. For example, the RF control signal output from the analog multiplier can be amplified and shaped by the RF operational amplifier to ensure that the amplitude range, output impedance, and drive capability of the RF drive signal meet the input requirements of the RF power amplifier.

[0132] By setting up an RF drive conditioning unit, the potential problems of insufficient driving capability and impedance mismatch when the signal modulation unit directly drives the RF power amplifier can be reduced, and the power adjustment result corresponding to the amplitude control signal can be accurately applied to the RF power amplifier.

[0133] Optionally, the radio frequency (RF) reference signal can be provided by an RF signal generation circuit located outside the RF power supply sampling and control circuit. The RF signal generation circuit is connected to the signal modulation unit and provides the signal modulation unit with an RF reference signal having preset frequency and phase characteristics. Placing the RF signal generation circuit outside the RF power supply sampling and control circuit does not affect the feedback signal processing, error comparison, proportional-integral adjustment, cross-limiting, and amplitude control signal generation processes within the RF power supply sampling and control circuit, which are implemented using continuous-time analog circuitry.

[0134] Optionally, the first given signal includes a power given signal that maintains a corresponding power given value in different time intervals and undergoes a step change between adjacent time intervals; When the second feedback signal does not meet the reflection limiting condition, the first adjustment branch is used to continuously adjust the first adjustment signal according to the deviation between the power set signal and the first feedback signal, so that the incident power represented by the first feedback signal follows the corresponding power set value in each time interval.

[0135] In this embodiment, the power setpoint signal is used to characterize the target incident power of the radio frequency power supply in different time intervals. Within each time interval, the power setpoint signal remains at the corresponding power setpoint value; when switching from one time interval to an adjacent time interval, the power setpoint signal changes abruptly from the power setpoint value corresponding to the current time interval to the power setpoint value corresponding to the next time interval. Different power setpoint values ​​can increase sequentially, decrease sequentially, or alternate in a preset order, and the duration of each time interval can be the same or different.

[0136] The power setpoint signal can be generated by a controller located outside the RF power sampling and control circuit, combined with a digital-to-analog converter circuit. Alternatively, it can be generated by a stepped signal generation circuit, an analog switch circuit, or other circuits capable of outputting multiple levels of analog signals. Each power setpoint value can have a preset mapping relationship with its corresponding target incident power, allowing the power setpoint values ​​in different time intervals to indicate the target incident power to be achieved within the corresponding time interval.

[0137] When the second feedback signal does not meet the reflection limiting condition, the first adjustment branch compares the power setpoint corresponding to the current time interval with the first feedback signal, and adjusts the first adjustment signal in the continuous-time analog signal domain according to the deviation between the two. The first limiting branch adjusts the signal at the amplitude control node according to the first adjustment signal, and the signal modulation unit adjusts the amplitude of the radio frequency control signal accordingly, so that the incident power represented by the first feedback signal changes towards the corresponding power setpoint in the current time interval and stabilizes near the power state corresponding to the power setpoint.

[0138] When the power setpoint signal steps to a higher power setpoint value between adjacent time intervals, the first adjustment branch continuously adjusts the first adjustment signal according to the deviation between the power setpoint signal and the first feedback signal, causing the incident power represented by the first feedback signal to change towards the higher power setpoint value. When the power setpoint signal steps to a lower power setpoint value, the first adjustment branch adjusts the first adjustment signal accordingly, causing the incident power represented by the first feedback signal to change towards the lower power setpoint value. Thus, within each time interval, the incident power represented by the first feedback signal can follow the change of the power setpoint value corresponding to that time interval.

[0139] Within the current time interval, when the first feedback signal approaches the corresponding power setpoint, the deviation between the first setpoint signal and the first feedback signal decreases. The first adjustment branch adjusts the first adjustment signal accordingly to keep the incident power within the power range corresponding to the current power setpoint, until the power setpoint signal enters the next time interval and undergoes the next step change.

[0140] If, during power tracking within any time interval, the second feedback signal satisfies the reflection limiting condition, the second limiting branch clamps the signal at the amplitude control node according to the second adjustment signal, ensuring that the reflected power limitation takes precedence over the power setpoint corresponding to the current time interval. Once the second feedback signal recovers to a point where the reflection limiting condition is no longer met, the first adjustment branch continues to perform continuous-time simulation adjustment based on the deviation between the power setpoint corresponding to the current time interval and the first feedback signal, causing the incident power to continue changing towards the power setpoint corresponding to the current time interval.

[0141] In this way, when the reflected power does not reach the limit, the first regulating branch can continuously complete the incident power tracking within each time interval and the power switching between adjacent time intervals. When the reflected power reaches the limit in any time interval, the second limiting branch can prioritize clamping the signal at the amplitude control node, making the reflected power limit take precedence over the tracking of the current step power setpoint. After the reflected power recovers to the allowable range, the first regulating branch can continue to perform the tracking of the current step power setpoint. Since both the first and second regulating branches use continuous-time analog regulation and work together on the amplitude control node, it helps to reduce abrupt changes in amplitude control signal, output power fluctuations, loop oscillations, and waveform overshoot during the switching process between step power tracking and reflected power limiting, thereby improving the smoothness of step power waveform switching and load adaptability.

[0142] For example, Figure 4 The RF voltage waveform is shown when the RF power supply is connected to a 50 Ω matched load. The upper waveform represents the incident RF voltage V_FWD in the RF output circuit, and the lower waveform represents the reflected RF voltage V_REF in the RF output circuit. A first given signal maintains a corresponding power setpoint in different time intervals and undergoes a step change between adjacent time intervals. A first adjustment branch continuously adjusts the first adjustment signal based on the deviation between the first given signal and the first feedback signal. A first limiting branch adjusts the signal at the amplitude control node based on the first adjustment signal. The signal modulation unit adjusts the amplitude of the RF control signal accordingly, causing the amplitude envelope of the incident RF voltage V_FWD to change stepwise in different time intervals. When the load is in a matched state, the impedance matching between the RF power supply and the load is high, and less RF energy is reflected from the load to the RF power supply. Therefore, the reflected RF voltage V_REF remains at a relatively low level. The sampling unit samples, combines, detects, and filters the RF output states corresponding to the incident and reflected RF voltages, and forms a first feedback signal and a second feedback signal to characterize the incident power and reflected power, respectively.

[0143] In a prototype test at an operating frequency of 13.56 MHz, after a step change in the first given signal, the incident power response corresponding to the RF output state entered a relatively stable state within less than 2 μs. The above operating frequency, load impedance, and settling time are merely examples under specific prototype and test conditions and do not constitute a limitation on the scope of protection of this application.

[0144] For example, Figure 5 The diagram illustrates the RF voltage control waveforms when the load of the RF power supply suddenly changes from a matched state to a mismatched state. The upper waveform represents the incident RF voltage V_FWD in the RF output circuit, and the lower waveform represents the reflected RF voltage V_REF in the RF output circuit.

[0145] When the load is in a matched state, the reflected RF voltage V_REF remains at a relatively low level, and the RF power supply mainly implements closed-loop regulation of the incident power based on the deviation between the first given signal and the first feedback signal. When the load impedance suddenly changes and the matching degree between the RF power supply and the load decreases, the RF energy reflected from the load to the RF power supply increases, and the amplitude of the reflected RF voltage V_REF increases rapidly accordingly, causing the second feedback signal generated by the sampling unit to change.

[0146] The second adjustment branch continuously adjusts the second adjustment signal based on the deviation between the second given signal and the second feedback signal. When the second feedback signal meets the reflection limiting condition, the second limiting branch clamps the signal at the amplitude control node according to the second adjustment signal, thus limiting the output power control amount of the RF power amplifier corresponding to the amplitude control signal. Accordingly, the amplitude envelopes of the incident RF voltage V_FWD and the reflected RF voltage V_REF gradually enter a limited state.

[0147] In a set of prototype tests, the load suddenly changed from a matched state to an open-circuit mismatch state at about 17 μs, and the amplitude of the reflected RF voltage V_REF immediately increased; after the second limiting branch was introduced, the amplitude envelope of the reflected RF voltage V_REF entered a relatively stable limited state within about 3 μs.

[0148] Therefore, when a sudden load mismatch occurs, the second regulation branch and the second limiting branch can directly respond to changes in reflected power within the continuous-time analog signal domain and clamp the signal at the amplitude control node. This allows for rapid limitation of the RF power amplifier's output power without immediately shutting down the entire RF power supply. This hardware-level reflected power limiting method helps reduce response delays caused by digital sampling, computation, and control command updates, and reduces the risk of impact and damage to the core components of the RF power amplifier caused by excessive reflected power. After the load mismatch is eliminated, the clamping effect can be released or weakened, allowing the RF power supply to resume incident power tracking, thereby improving the continuous operation capability of the RF power supply. The above time parameters are only examples under the corresponding prototype and test conditions.

[0149] Under the aforementioned prototype test conditions, after sampling calibration, the overall power sampling error of the RF power supply does not exceed ±1%, the effective bandwidth of the control loop is in the hundreds of kHz range, and the overall dynamic control response is in the μs range. The sampling error, control bandwidth, and dynamic response parameters mentioned above are test results obtained under specific prototype, device parameters, and test conditions, and are used for illustrative purposes.

[0150] Optionally, both the first feedback signal and the second feedback signal are output in the form of differential signals; The first regulating branch includes a first differential receiving circuit, which is used to convert the differential form of the first feedback signal into a first single-ended feedback signal for use by the first regulating branch. The second regulation branch includes a second differential receiving circuit, which is used to convert the differential form of the second feedback signal into a second single-ended feedback signal for use by the second regulation branch.

[0151] In this embodiment, the sampling unit transmits the first feedback signal and the second feedback signal in a pair of differential components. The first differential receiving circuit performs differential amplification and common-mode suppression on the differential form of the first feedback signal to generate the first single-ended feedback signal; the second differential receiving circuit processes the differential form of the second feedback signal accordingly to generate the second single-ended feedback signal.

[0152] The first single-ended feedback signal and the second single-ended feedback signal are respectively provided to the first error comparison circuit and the second error comparison circuit to participate in incident power adjustment and reflected power limitation. The differential receiving circuit may include a differential amplifier, an instrumentation amplifier, or a differential conversion circuit composed of an operational amplifier and a resistor network. By using differential transmission and differential reception, common-mode interference coupled to the two signal lines in the transmission path can be suppressed, which is beneficial to improving the anti-interference capability of the feedback signal.

[0153] For example, combined Figure 2As shown, the sampling unit may include a directional coupler sampling unit 110, a sampling signal processing unit 120, an incident voltage differential amplification unit 111, and a reflected voltage differential amplification unit 112. The sampling signal processing unit 120 generates an incident power sampling signal and a reflected power sampling signal based on the RF current sampling signal and the RF voltage sampling signal. The incident power sampling signal can be converted into a differential form first feedback signal RF-F by the incident voltage differential amplification unit 111, and the reflected power sampling signal can be converted into a differential form second feedback signal RF-R by the reflected voltage differential amplification unit 112. The incident voltage differential amplification unit 111 and the reflected voltage differential amplification unit 112 may each include a differential output circuit or a differential drive circuit to convert the corresponding single-ended sampling signals into feedback signals suitable for differential transmission. The first feedback signal RF-F and the second feedback signal RF-R can be transmitted to the analog control unit 140 through corresponding differential shielded lines. Figure 2 In this context, RF-F and RF-R represent the overall signal names of the first feedback signal and the second feedback signal, respectively, and both can be transmitted in a differential manner.

[0154] Combination Figure 3 As shown, the incident voltage signal conditioning unit 131 may include a first differential receiving circuit. The first differential receiving circuit receives a differential form of the first feedback signal RF-F and converts the two differential components RF-FFp and RF-FFn of the first feedback signal RF-F into a first single-ended feedback signal RF-FF. The reflected voltage signal conditioning unit 132 may include a second differential receiving circuit. The second differential receiving circuit receives a differential form of the second feedback signal RF-R and converts the two differential components RF-RFp and RF-RFn of the second feedback signal RF-R into a second single-ended feedback signal RF-RF. The incident voltage signal conditioning unit 131 and the reflected voltage signal conditioning unit 132 may also perform proportional conditioning, filtering, or level conversion on the corresponding differential components and / or single-ended feedback signals, and provide the first single-ended feedback signal RF-FF and the second single-ended feedback signal RF-RF to the first error comparison circuit and the second error comparison circuit in the dual-loop cross-limiting and proportional-integral adjustment unit 133, respectively.

[0155] It should be noted that, Figure 2 In this context, RF-F and RF-R are used to represent the overall signal names of the first feedback signal and the second feedback signal, respectively. Figure 3In this diagram, RF-FFp and RF-FFn represent the two differential components of the first feedback signal RF-F, and RF-RFp and RF-RFn represent the two differential components of the second feedback signal RF-R. RF-FF and RF-RF represent the first and second single-ended feedback signals formed after differential reception processing, respectively. These signal identifiers are used to distinguish the signal forms of the corresponding feedback signals at different processing stages and do not indicate that the corresponding signals are independent feedback signals.

[0156] Optionally, the sampling unit is connected to the first adjustment branch and the second adjustment branch through corresponding differential shielding lines.

[0157] In this embodiment, the first feedback signal and the second feedback signal are transmitted through corresponding differential shielded lines. Each differential shielded line includes a signal conductor for transmitting a pair of differential signals and a shielding layer covering the outside of the signal conductor. The shielding layer can be connected to a reference ground, chassis ground, or other preset shielding potential.

[0158] Differential shielded cables can be shielded twisted-pair cables or other cables with differential transmission and electromagnetic shielding functions. By twisting the two signal lines corresponding to the same feedback signal together and using a shielding layer to reduce the coupling of external radio frequency electromagnetic fields to the signal lines, interference from the radio frequency power amplifier and radio frequency output circuit to the feedback signal transmission can be reduced.

[0159] Optionally, the sampling unit includes a current sampling unit, a voltage sampling unit, a calibration unit, and a detection unit; The current sampling unit is used to collect the radio frequency current in the output circuit of the radio frequency power supply and generate the radio frequency current sampling signal; The voltage sampling unit is used to acquire the radio frequency voltage in the output circuit of the radio frequency power supply and generate the radio frequency voltage sampling signal; The calibration unit is used to calibrate at least one of the phase relationship and amplitude relationship between the radio frequency current sampling signal and the radio frequency voltage sampling signal; The detection unit is used to perform detection processing based on the calibrated radio frequency current sampling signal and radio frequency voltage sampling signal to generate a first feedback signal and a second feedback signal.

[0160] In this embodiment, the current sampling unit and the voltage sampling unit acquire sampling signals corresponding to the RF output current and RF output voltage from the RF power supply output circuit, respectively. Since the transmission characteristics, device parameters, and parasitic parameters of different sampling branches may cause amplitude or phase deviations between the two sampling signals, the amplitude and phase of the two sampling signals are calibrated by the calibration unit before power detection.

[0161] The detection unit combines and detects calibrated RF current and RF voltage sampling signals to generate an incident power sampling signal for forming a first feedback signal and a reflected power sampling signal for forming a second feedback signal. Specifically, the calibrated RF current and RF voltage sampling signals are provided to the detection unit. The detection unit can generate RF components corresponding to the incident and reflected waves based on the combination relationship of the two sampling signals, and detect the corresponding RF components to generate the incident power sampling signal and the reflected power sampling signal, respectively. After filtering and differential output processing, the incident power sampling signal and the reflected power sampling signal form the first feedback signal characterizing the incident power and the second feedback signal characterizing the reflected power, respectively. This reduces the impact of sampling branch amplitude and phase errors on the accuracy of incident and reflected power detection.

[0162] Optionally, the sampling unit can adopt a split sampling structure, with the current sampling unit, voltage sampling unit, and sampling signal processing unit set up separately and connected through corresponding signal transmission paths. The current sampling unit and voltage sampling unit acquire the radio frequency current sampling signal and radio frequency voltage sampling signal, respectively. The sampling signal processing unit then performs calibration, combination, detection, and filtering processing on the radio frequency current sampling signal and radio frequency voltage sampling signal. Using a split sampling structure allows for the configuration of different sampling branches according to the structure of the radio frequency output circuit and its withstand voltage, insulation, and impedance matching requirements.

[0163] Optionally, the sampling unit further includes a feedback signal compensation and calibration circuit, which is connected to the output side of the detection unit or the filtering unit. The feedback signal compensation and calibration circuit is used to perform amplitude calibration and DC bias compensation on at least one of the first feedback signal and the second feedback signal, such as to perform amplitude calibration and DC bias compensation on at least one of the incident power sampling signal and the reflected power sampling signal, so that the compensated and calibrated incident power sampling signal and reflected power sampling signal are used to form the first feedback signal and the second feedback signal, respectively.

[0164] Specifically, amplitude calibration can be used to correct gain errors introduced by parameter dispersion in current transformers, capacitive voltage divider networks, detector diodes, filter networks, and differential amplifier circuits; DC bias compensation can be used to correct zero-point offsets introduced by detector diode conduction characteristics, operational amplifier input offset, and parasitic parameters in circuit wiring. The feedback signal compensation calibration circuit may include at least one of an operational amplifier, an adjustable resistor, a reference voltage circuit, and a resistor-capacitor network.

[0165] In some embodiments, under standard load and preset RF power conditions, the gain and bias of the feedback signal compensation calibration circuit can be adjusted according to the deviation between the first feedback signal and the second feedback signal and the corresponding standard power value, such as according to the deviation between the first feedback signal and the second feedback signal formed after compensation calibration and the corresponding standard power value, so that the first feedback signal and the second feedback signal respectively satisfy the corresponding preset mapping relationship.

[0166] Optionally, the current sampling unit includes a current transformer coupled to the radio frequency output conductor; The voltage sampling unit includes a capacitor divider network coupled to the RF power output circuit.

[0167] In this embodiment, a current transformer is positioned at the corresponding location of the RF output conductor and senses the RF current flowing through the RF output conductor via magnetic coupling, generating a current sampling signal corresponding to the RF current. The current transformer can be sleeved outside the RF output conductor, or it can form an inductive coupling structure with the RF output conductor through a magnetic core.

[0168] A capacitive voltage divider network includes at least two voltage divider capacitors with preset capacitance values, used for voltage division and sampling of the RF voltage in the RF power supply output circuit. By configuring the capacitance values ​​of each voltage divider capacitor, the voltage sampling signal can be kept within the amplitude range that the subsequent calibration and detection circuits can handle. Using current transformers and capacitive voltage divider networks for indirect or high-impedance sampling helps reduce the impact of the sampling circuit on the operating state of the RF output circuit.

[0169] For example, combined Figure 2 As shown, the current sampling unit can employ a current transformer CT1. The current transformer CT1 may include a nickel-zinc magnetic ring and an induction winding wound around the nickel-zinc magnetic ring. The RF output conductor in the RF power amplifier output circuit passes through the nickel-zinc magnetic ring, creating a magnetic coupling relationship between the current transformer CT1 and the RF output conductor to induce the RF current flowing through the RF output conductor. The induction winding of the current transformer CT1 generates a differential RF current sampling signal based on the induced RF current. The RF current sampling signal includes a differential output signal CT1-P and a differential output signal CT1-N, which are provided to the sampling signal processing unit 120. It should be noted that CT1-P and CT1-N represent two differential components of the same RF current sampling signal, and their identifiers are used to distinguish the corresponding differential components and their polarity relationship.

[0170] The RF signal output by the RF power amplifier 109 can be input to the RF output conductor via port 1 and transmitted along the RF output conductor to port 2. The RF signal at port 2 is labeled as the RF output signal RF-OUT, which is used to transmit RF power to the matching network or load. Furthermore, Figure 2 The arrow in the diagram indicates the preset positive direction of the RF output current, and together with the winding direction of the current transformer CT1, it is used to determine the polarity relationship between the differential output signals CT1-P and CT1-N; GND indicates the reference ground or shielding ground corresponding to the RF output structure.

[0171] For example, combined Figure 2 As shown, the voltage sampling unit may include a first voltage sampling branch and a second voltage sampling branch, both of which are coupled to the RF output node RF-OUT in the RF power amplifier output circuit. It should be noted that... Figure 2 The RF-OUT markings at different locations indicate RF output nodes with the same electrical connection, not multiple independent RF output terminals. The first voltage sampling branch may include voltage-dividing capacitors C1 and C4, and the second voltage sampling branch may include voltage-dividing capacitors C7 and C12. The first and second voltage sampling branches respectively perform voltage division sampling on the RF voltage at the RF output node RF-OUT to form RF voltage sampling signals corresponding to the two power detection branches. The first voltage sampling branch may also include resistor R1 and adjustable capacitor C3, and the second voltage sampling branch may also include resistor R10 and adjustable capacitor C11. Resistors R1 and R10 can be used for impedance isolation of the corresponding voltage sampling branches or to reduce the load influence of subsequent circuits; adjustable capacitors C3 and C11 can be used to adjust the voltage division ratio, amplitude relationship, or phase relationship of the corresponding voltage sampling branches. The number, connection method, and parameters of the capacitors and resistors described above are only one example. In other embodiments, other voltage sampling structures that can meet the corresponding voltage division ratio, withstand voltage requirements, and amplitude-phase calibration requirements can also be used.

[0172] The voltage sampling unit may include a multi-stage capacitor voltage divider network composed of voltage-dividing capacitors C1, C4, C7, and C12. This multi-stage capacitor voltage divider network is coupled to the output circuit of the RF power amplifier, used to divide the RF voltage in the RF output circuit, and provide the divided RF voltage sampling signal to the sampling signal processing unit 120. The above-described number of capacitors and connection method are only one example; in other embodiments, other numbers of voltage-dividing capacitors may be used to construct a capacitor voltage divider network that meets the corresponding voltage division ratio and withstand voltage requirements.

[0173] Optionally, the calibration unit includes an adjustable reactance device disposed in at least one of the current sampling branch and the voltage sampling branch; Adjustable reactance devices are used to adjust at least one of the phase difference and amplitude ratio between the radio frequency current sampling signal and the radio frequency voltage sampling signal.

[0174] In this embodiment, the adjustable reactance device is connected in series or parallel in at least one of the current sampling branch and the voltage sampling branch. By changing the reactance value of the adjustable reactance device, the transmission phase and impedance characteristics of the corresponding sampling branch at the radio frequency can be changed, thereby adjusting the phase difference and amplitude ratio between the two sampled signals.

[0175] During calibration, the first and second feedback signals can be detected under preset load or standard power conditions. Based on the detection results, the adjustable reactance device is adjusted to ensure that the RF current sampling signal and the RF voltage sampling signal satisfy a preset amplitude-phase relationship. The adjustable reactance device can be an adjustable inductor, an adjustable capacitor, a varactor diode, or a stepped adjustment network composed of fixed reactance devices and switching devices.

[0176] Optionally, the adjustable reactance device includes a compensating inductor disposed in the current sampling branch, and an adjustable capacitor disposed in at least one of the current sampling branch and the voltage sampling branch.

[0177] In this embodiment, a compensating inductor is disposed in the current sampling branch to compensate for the phase shift introduced by the current transformer, connecting conductors, and subsequent circuits. An adjustable capacitor is disposed in at least one of the current sampling branch and the voltage sampling branch to further adjust the capacitive reactance and transmission characteristics of the corresponding sampling branch.

[0178] By adjusting the compensation inductor and the adjustable capacitor, the two sampling branches can have matched amplitude and phase responses at the RF power supply operating frequency. The adjustable capacitor can be a mechanically adjustable capacitor, a digitally adjustable capacitor, a varactor diode, or a switchable capacitor network consisting of multiple capacitors and switches.

[0179] For example, combined Figure 2 As shown, the compensation inductor can be inductor L1 located in the current sampling branch, used to compensate for the phase lag introduced by the current sampling branch. The adjustable capacitors can include capacitors C2 and C10, which can be respectively located in their respective sampling branches to adjust the phase relationship between the RF current sampling signal and the RF voltage sampling signal. Capacitors C3 and C11 can be used to set or calibrate the voltage division ratio or amplitude relationship of the corresponding voltage sampling branch. By adjusting the above reactive devices, the RF current sampling signal and the RF voltage sampling signal can satisfy the corresponding amplitude and phase relationship at the preset RF operating frequency, thereby improving the accuracy of incident power and reflected power detection.

[0180] Optionally, the sampling unit further includes an isolation resistor connected in series between the current sampling unit and the detection unit and / or between the voltage sampling unit and the detection unit; Isolation resistors are used to reduce the load impact of the detection unit and its subsequent signal processing circuits on the current sampling unit and / or voltage sampling unit.

[0181] In this embodiment, an isolation resistor is connected in series in the transmission path of the corresponding sampled signal to form impedance isolation between the sampling front-end and the detection unit. When the conduction state of the detection diode or the input impedance of the subsequent signal processing circuit changes, the isolation resistor can limit the transmission of the change to the sampling front-end, thereby reducing the impact of the detection unit on the amplitude and phase characteristics of the current sampling branch and the voltage sampling branch.

[0182] The value of the isolation resistor can be determined by considering the sampling signal frequency, the input impedance of the detector unit, and the allowable signal attenuation. In some embodiments, corresponding isolation resistors are provided for the current sampling branch and the voltage sampling branch respectively, in order to improve the consistency and isolation between the two sampling branches.

[0183] For example, combined Figure 2 As shown, the first voltage sampling branch and the second voltage sampling branch can be equipped with isolation resistors R1 and R10, respectively. Isolation resistors R1 and R10 are connected in series in the transmission path of the corresponding voltage sampling signal to form impedance isolation between the corresponding voltage sampling front end and the detection unit, thereby reducing the impact of input impedance changes of the detection unit, filtering unit, and subsequent signal conditioning circuit on the amplitude and phase of the corresponding RF voltage sampling signal.

[0184] Optionally, the detection unit includes a high-frequency Schottky detector diode; The sampling unit also includes a filtering unit connected to the output of the detection unit. The filtering unit includes at least one of an LC filter circuit and an RC filter circuit.

[0185] In this embodiment, a high-frequency Schottky detector diode is used to rectify and detect the incident and reflected radio frequency signals formed by the combination. The Schottky detector diode has a low forward voltage drop and a fast switching response, making it suitable for detecting high-frequency, low-amplitude sampled signals.

[0186] A filter unit is installed at the output of the detector unit to filter out the radio frequency carrier component and high-frequency ripple in the detected signal, retaining the envelope signal or DC signal that can characterize the corresponding power level. An LC filter circuit can be used to suppress higher frequency radio frequency components, and an RC filter circuit can be used to smooth the detector output. These two circuits can be set individually or sequentially to form a first feedback signal and a second feedback signal that meet the feedback bandwidth requirements.

[0187] For example, combined Figure 2 As shown, the detection unit may include high-frequency Schottky detector diodes VD1 and VD2, and the filtering unit may include filter inductors L2 and L3, filter capacitors C5 and C8, and at least a portion of conditioning resistors R2, R3, R5, R6, R7, R8, R11, and R12. The aforementioned inductors, capacitors, and resistors can form an LC-RC low-pass filter network to filter out the radio frequency carrier component, high-frequency ripple, and pulse interference in the signal after peak detection, forming an incident power sampling signal that can characterize the incident power and a reflected power sampling signal that can characterize the reflected power, respectively. The incident power sampling signal and the reflected power sampling signal can be further converted into differential form first feedback signals and second feedback signals by the incident voltage differential amplifier unit 111 and the reflected voltage differential amplifier unit 112.

[0188] By employing differential transmission and reception of the first and second feedback signals, common-mode interference coupled to the two differential signal lines in the transmission path can be suppressed. By setting differential shielding lines, the coupling effect of the RF electromagnetic field generated by the RF power amplifier and RF output circuit on the feedback signal transmission path can be reduced. Furthermore, by setting LC and / or RC filter circuits on the output side of the detector unit, RF carrier components, high-frequency ripple, and pulse interference in the detector signal can be filtered out. The combined effect of these structures improves the anti-interference capability and transmission stability of the feedback signal in RF operating environments such as 13.56MHz, and reduces the possibility of power control deviations, output power fluctuations, or stepped power waveform jitter caused by feedback signal distortion.

[0189] Optionally, the RF power supply sampling and control circuit also includes a constant temperature control unit, which includes a temperature detection subunit and a temperature regulation subunit. The temperature detection subunit is used to detect the temperature of at least one temperature-sensitive sampling device in the sampling unit; The temperature regulation subunit is used to adjust the temperature of the environment in which the temperature-sensitive sampling device is located based on the temperature detected by the temperature detection subunit, so as to maintain the temperature of the environment in which the temperature-sensitive sampling device is located within a preset temperature range.

[0190] In this embodiment, the temperature detection subunit is located near the temperature-sensitive sampling device and is used to collect temperature signals that characterize the operating temperature of the temperature-sensitive sampling device. The temperature regulation subunit controls the operation of the heating device, heat dissipation device, or other temperature regulation devices based on the relationship between the detected temperature and a preset target temperature or a preset temperature range.

[0191] When the detected temperature is below the preset temperature range, the temperature regulation subunit can control the heating device to raise the ambient temperature of the temperature-sensitive sampling device; when the detected temperature reaches or exceeds the preset temperature range, it can reduce the heating power, stop heating, or enhance heat dissipation. This reduces the drift in sampling ratio, phase relationship, and detection characteristics caused by changes in ambient temperature.

[0192] The temperature detection subunit may include a thermistor, a temperature sensor chip, or other temperature detection elements; the temperature regulation subunit may include at least one of a heating resistor, a semiconductor temperature control device, a cooling fan, and a corresponding drive circuit.

[0193] Optionally, the temperature-sensitive sampling device includes at least one of a current transformer, a voltage divider capacitor in a capacitive voltage divider network, and a detector diode in a detector unit.

[0194] In this embodiment, the permeability and winding parameters of the current transformer may change with temperature, the capacitance and loss characteristics of the voltage divider capacitor may also be affected by temperature, and the forward voltage drop and junction characteristics of the detector diode are also temperature-dependent. Therefore, at least one of the above devices can be identified as a temperature-sensitive sampling device, and its temperature can be detected and adjusted.

[0195] In some embodiments, the current transformer, voltage divider capacitor, and detector diode are jointly disposed within a constant-temperature region. A temperature detection subunit detects the temperature of this constant-temperature region, and a temperature regulation subunit performs uniform temperature regulation on the constant-temperature region. Alternatively, local constant-temperature control can be applied only to devices whose temperature drift significantly affects sampling accuracy, thus balancing sampling stability and temperature control power consumption.

[0196] For example, combined Figure 2 As shown, the constant temperature control unit 121 can be arranged around the directional coupler sampling unit 110 and the sampling signal processing unit 120, and corresponding to at least one of the current transformer CT1, the voltage divider sampling capacitor, and the high-frequency Schottky detector diodes VD1 and VD2. The temperature detection subunit can be arranged near the aforementioned temperature-sensitive sampling device, and the temperature regulation subunit can regulate the temperature of the local area where the temperature-sensitive sampling device is located through a heating element, a heating resistor, a semiconductor temperature control device, a heat dissipation structure, or an air-cooling structure.

[0197] In some embodiments, the constant temperature control unit 121 may be installed in a way that covers or adheres to the mounting area of ​​the directional coupler sampling unit 110 and the sampling signal processing unit 120, so as to shorten the heat transfer path between the temperature regulating device and the temperature-sensitive sampling device and maintain the temperature of the environment where the temperature-sensitive sampling device is located within a preset temperature range.

[0198] By coordinating the constant temperature control unit with the aforementioned feedback signal compensation and calibration circuit, the impact of ambient temperature changes on the parameters of temperature-sensitive sampling devices such as current transformers, voltage divider capacitors, and detector diodes can be reduced through constant temperature control. Furthermore, amplitude calibration and DC bias compensation can correct sampling deviations introduced by the dispersion of sampling device parameters, operational amplifier input offset, and circuit parasitic parameters. This helps reduce feedback signal drift caused by temperature changes and differences in device parameters, improves the long-term sampling stability of incident and reflected power, and further enhances the stability of power closed-loop control and stepped power waveform output.

[0199] Another embodiment of the present invention provides an radio frequency power supply, including the radio frequency power supply sampling and control circuit described above.

[0200] In this embodiment, the RF power supply sampling and control circuit is used to sample the output state of the RF power supply and perform closed-loop regulation of the RF power supply's output power based on incident power feedback and reflected power feedback. The RF power supply sampling and control circuit can be integrated inside the RF power supply or connected as an independent control board to other functional circuits within the RF power supply.

[0201] Radio frequency (RF) power supplies can be applied to plasma generation, semiconductor processing, RF heating, medical RF, communication testing, or other scenarios requiring RF power output. The output of the RF power supply can be connected to a load via a matching network, and a sampling unit can be coupled to the output circuit of the RF power supply to acquire the RF voltage, RF current, or other signals that can characterize the RF output state in the output circuit, and generate a first feedback signal and a second feedback signal accordingly.

[0202] For example, the RF power supply also includes an RF power amplifier. The RF power amplifier amplifies the power of the input RF drive signal and outputs RF power to the load through its output. A sampling unit may be coupled to the output circuit of the RF power amplifier to generate a first feedback signal characterizing the incident power and a second feedback signal characterizing the reflected power based on the output signal of the RF power amplifier.

[0203] The first adjustment branch in the RF power supply sampling and control circuit performs continuous-time simulation adjustment based on the deviation between the first given signal and the first feedback signal, so as to change the incident power in the RF power supply output circuit towards the target incident power. The second adjustment branch performs continuous-time simulation adjustment based on the deviation between the second given signal and the second feedback signal, and when the reflected power reaches the corresponding limit condition, clamps the signal at the amplitude control node through a cross-limiting circuit, thereby limiting the output power of the RF power amplifier.

[0204] In some embodiments, the amplitude control signal output by the RF power sampling and control circuit can provide a power regulation path to the input side of the RF power amplifier to regulate the amplitude of the RF drive signal input to the RF power amplifier. The power regulation path may include an analog multiplier, a variable gain amplifier, a voltage-controlled attenuator, or other circuits capable of changing the amplitude of the RF drive signal according to the amplitude control signal.

[0205] When the RF power supply sampling and control circuit includes a signal modulation unit, the signal modulation unit can adjust the amplitude of the RF reference signal according to the amplitude control signal to generate an RF control signal. This RF control signal is then directly provided to the RF power amplifier, or it can be buffered, filtered, or pre-amplified before being provided to the RF power amplifier. The RF power amplifier amplifies the RF control signal to form the RF power supply's output signal. The sampling unit then samples this output signal, thus forming a closed-loop control link.

[0206] By setting the above-mentioned RF power sampling and control circuit in the RF power supply, the incident power can be continuously simulated and closed-loop regulated under normal load conditions, and the output power of the RF power amplifier can be limited in time when the reflected power increases due to load mismatch. This is beneficial to balance the power tracking performance, dynamic response performance and operational safety of the RF power supply.

[0207] Optionally, the RF power supply also includes an RF signal generation circuit. This RF signal generation circuit is set independently of the RF power supply sampling and control circuit and is connected to the signal modulation unit to provide an RF reference signal to the signal modulation unit. For example, the RF signal generation circuit may include a direct digital frequency synthesizer (DDS), and the RF reference signal may be a sinusoidal signal formed based on the output signal of the DDS. The signal output by the DDS may be provided to the signal modulation unit after undergoing at least one of the following processing steps: digital-to-analog conversion, filtering, buffering, and amplitude conditioning. The DDS serves as an external RF reference signal source, internally employing digital signal synthesis, and does not affect the continuous-time analog architecture used in the power feedback closed loop of the RF power supply sampling and control circuit.

[0208] For example, the RF power supply sampling and control circuit can be used for RF power supplies with operating frequencies in the range of 1MHz to 30MHz. For instance, the operating frequency of the RF power supply can be 13.56MHz.

[0209] The RF power supply sampling and control circuit can be integrated inside the RF power supply or formed as an independent control board, connected to the RF power amplifier, external RF signal generation circuit, and other functional circuits. Since the feedback closed-loop control link can be primarily implemented using continuous-time analog devices, without the need for high-speed analog-to-digital converters and high-performance digital processors for feedback closed-loop calculations, it simplifies the hardware configuration and software / hardware debugging process of the RF power supply, reduces manufacturing and maintenance costs, and facilitates modular configuration according to different RF power levels, operating frequencies, and application scenarios. This makes it suitable for mass production and long-term industrial operation of RF power supplies.

[0210] Another embodiment of the present invention provides a radio frequency power supply sampling and control method, comprising: A first feedback signal characterizing the incident power and a second feedback signal characterizing the reflected power are generated based on the output signal of the radio frequency power supply. Based on the deviation between the first given signal and the first feedback signal, continuous-time simulation adjustment is performed to generate the first adjustment signal; Based on the deviation between the second given signal and the second feedback signal, continuous-time simulation adjustment is performed to generate the second adjustment signal; Based on the first and second adjustment signals, cross-limiting processing is performed on the signal at the amplitude control node; Cross-limiting processing includes: When the second feedback signal does not meet the reflection limiting condition, the signal at the amplitude control node is adjusted by the first limiting branch according to the first adjustment signal; when the second feedback signal meets the reflection limiting condition, the signal at the amplitude control node is clamped by the second limiting branch according to the second adjustment signal to generate an amplitude control signal for adjusting the output power of the RF power amplifier.

[0211] This embodiment's method can be implemented based on the aforementioned RF power supply sampling and control circuit. For example, a sampling unit can generate a first feedback signal and a second feedback signal based on the RF power supply's output signal. The first and second adjustment branches perform continuous-time analog adjustment based on the deviation between the corresponding given signal and the feedback signal, respectively. A cross-limiting circuit performs cross-limiting processing on the signal at the amplitude control node based on the first and second adjustment signals to generate an amplitude control signal. Accordingly, this embodiment's method is used to control the RF power supply. The RF power supply's output signal can include the RF voltage signal and RF current signal in the RF power amplifier output circuit. By sampling, combining, and detecting the RF voltage and current signals, a first feedback signal characterizing the RF power supply's incident power and a second feedback signal characterizing the RF power supply's reflected power can be generated. The first and second feedback signals can be analog voltage or analog current signals that continuously change with the corresponding power. The first given signal characterizes the target incident power, and the second given signal characterizes the reflected power limit value. The first and second given signals can be generated by an analog given circuit or output by a controller located outside the RF power supply sampling and control circuit in conjunction with a digital-to-analog converter circuit. The first given signal, the second given signal, the first feedback signal, and the second feedback signal can represent the corresponding power values ​​according to a preset correspondence, so as to be compared and adjusted in the analog signal domain.

[0212] Specifically, a first given signal is compared with a first feedback signal to generate a first deviation signal characterizing the deviation between the target incident power and the actual incident power. Continuous-time simulation adjustment is then performed based on the first deviation signal to generate a first adjustment signal. The continuous-time simulation adjustment may include proportional adjustment, integral adjustment, or proportional-integral adjustment, causing the first adjustment signal to change continuously with the first deviation signal.

[0213] Simultaneously, the second given signal is compared with the second feedback signal to generate a second deviation signal characterizing the deviation between the reflected power limit value and the actual reflected power. Continuous-time simulation adjustment is then performed based on the second deviation signal to generate a second adjustment signal. The first and second adjustment signals are respectively provided to the first and second limiting branches, so that the first and second limiting branches act on the amplitude control node according to their respective adjustment signals.

[0214] It should be noted that the generation processes of the first and second adjustment signals can be carried out in parallel and continuously, and are not required to be performed in the order of first generating the first adjustment signal and then generating the second adjustment signal. Accordingly, the first and second adjustment branches can continuously respond to the incident power deviation and the reflected power deviation, respectively, and adjust their respective output adjustment signals in real time according to the corresponding deviations.

[0215] The outputs of both the first and second limiting branches act on the amplitude control node, thereby enabling incident power adjustment and reflected power limitation to act on the same amplitude control node together, and forming a cross-limiting relationship between the first and second limiting branches, so as to determine the signal adjustment mode at the amplitude control node according to the current reflected power state.

[0216] When the second feedback signal does not meet the reflection limiting condition, it indicates that the current reflected power is lower than the reflected power limit value, and the second limiting branch does not exert a dominant clamping effect on the signal at the amplitude control node. At this time, the first limiting branch adjusts the signal at the amplitude control node according to the first adjustment signal, so that the resulting amplitude control signal changes in the direction of reducing the deviation between the first given signal and the first feedback signal.

[0217] For example, when the actual incident power represented by the first feedback signal is lower than the target incident power represented by the first given signal, the first adjustment branch adjusts the first adjustment signal accordingly, and adjusts the signal at the amplitude control node through the first limiting branch, so that the output power of the RF power amplifier changes in the direction of increasing the incident power. When the actual incident power is higher than the target incident power, the first adjustment branch adjusts the first adjustment signal accordingly, so that the output power of the RF power amplifier changes in the direction of decreasing the incident power.

[0218] When the second feedback signal satisfies the reflection limiting condition, for example, when the reflected power represented by the second feedback signal is greater than or equal to the reflected power limit value represented by the second given signal, the second adjustment branch continuously adjusts the second adjustment signal according to the deviation between the second given signal and the second feedback signal. The second limiting branch clamps the signal at the amplitude control node according to the second adjustment signal, thereby limiting the amplitude control signal and restricting the output power of the RF power amplifier from continuing to change in the direction that increases the reflected power.

[0219] In some embodiments, during the clamping process of the second limiting branch, the first adjustment branch can continue to generate a first adjustment signal based on the deviation between the first given signal and the first feedback signal, but the adjustment of the signal at the amplitude control node by the first limiting branch is limited by the second limiting branch. Therefore, when there is a conflict between target incident power tracking and reflected power limiting, the reflected power limiting requirement can be prioritized.

[0220] When the load mismatch decreases, causing the second feedback signal to recover to a level that does not meet the reflection limiting condition, the clamping effect of the second limiting branch on the signal at the amplitude control node weakens or is released accordingly. The first limiting branch then resumes its primary regulating role on the signal at the amplitude control node based on the first adjustment signal, enabling the RF power supply to resume tracking the target incident power. Since both adjustment branches employ continuous-time analog adjustment, the entry and exit of the cross-limiting state can change continuously with the feedback signal, which helps reduce abrupt changes in the amplitude control signal during control state switching.

[0221] For example, the generated amplitude control signal can be provided to an analog multiplier, variable gain amplifier, voltage-controlled attenuator, or other power regulation circuit on the input side of the RF power amplifier to adjust the amplitude of the RF drive signal input to the RF power amplifier. The RF power amplifier outputs the corresponding RF power according to the adjusted RF drive signal, and the sampling unit updates the first feedback signal and the second feedback signal again according to the output signal of the RF power supply, thereby forming a closed-loop control process.

[0222] Therefore, the method in this embodiment can perform continuous-time simulated closed-loop adjustment of the incident power when the reflected power does not reach the limit condition, and clamp the amplitude control signal in a timely manner when the reflected power reaches the limit condition. This is beneficial for achieving a fast and smooth switching between incident power control and reflected power limitation, and improving the dynamic response performance and operational reliability of the RF power supply.

[0223] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A radio frequency power supply sampling and control circuit, characterized in that, include: A sampling unit is used to generate a first feedback signal characterizing the incident power and a second feedback signal characterizing the reflected power based on the output signal of the radio frequency power supply. The first adjustment branch is used to receive the first given signal and the first feedback signal, and to perform continuous-time analog adjustment based on the deviation between the first given signal and the first feedback signal to generate the first adjustment signal; The second adjustment branch is used to receive the second given signal and the second feedback signal, and to perform continuous-time analog adjustment based on the deviation between the second given signal and the second feedback signal to generate the second adjustment signal; A cross-limiting circuit includes a first limiting branch connected to the first adjustment branch and a second limiting branch connected to the second adjustment branch. The output terminals of the first limiting branch and the second limiting branch are respectively connected to an amplitude control node. The cross-limiting circuit is used to cause the first limiting branch to adjust the signal at the amplitude control node according to the first adjustment signal when the second feedback signal does not meet the reflection limiting condition, and to cause the second limiting branch to clamp the signal at the amplitude control node according to the second adjustment signal when the second feedback signal meets the reflection limiting condition, so as to generate an amplitude control signal for adjusting the output power of the RF power amplifier.

2. The radio frequency power supply sampling and control circuit as described in claim 1, characterized in that, The first given signal is used to characterize the target incident power, and the second given signal is used to characterize the reflection power limit value; the reflection limiting condition includes the reflection power characterized by the second feedback signal being greater than or equal to the reflection power limit value.

3. The radio frequency power supply sampling and control circuit as described in claim 1, characterized in that, The first adjustment branch includes a first error comparison circuit and a first proportional-integral adjustment circuit. The first error comparison circuit is used to generate a first deviation signal based on the first given signal and the first feedback signal. The first proportional-integral adjustment circuit is used to generate the first adjustment signal based on the first deviation signal. And / or, the second adjustment branch includes a second error comparison circuit and a second proportional-integral adjustment circuit, wherein the second error comparison circuit is used to generate a second deviation signal based on the second given signal and the second feedback signal, and the second proportional-integral adjustment circuit is used to generate a second adjustment signal based on the second deviation signal.

4. The radio frequency power supply sampling and control circuit as described in claim 3, characterized in that, The first limiting branch includes a first transistor limiting circuit and a first cross-limiting diode, and the second limiting branch includes a second transistor limiting circuit and a second cross-limiting diode; The anode of the first cross-limiting diode is connected to the output terminal of the first transistor limiting circuit, and the cathode of the first cross-limiting diode is connected to the output terminal of the second proportional-integral adjustment circuit. The anode of the second cross-limiting diode is connected to the output terminal of the second transistor limiting circuit, and the cathode of the second cross-limiting diode is connected to the output terminal of the first proportional-integral adjustment circuit.

5. The radio frequency power supply sampling and control circuit as described in claim 4, characterized in that, A first bypass resistor is connected in parallel across the two ends of the first cross-limiting diode, and a second bypass resistor is connected in parallel across the two ends of the second cross-limiting diode.

6. The RF power supply sampling and control circuit as described in any one of claims 1-5, characterized in that, It also includes a signal modulation unit, which is used to receive the amplitude control signal and the radio frequency reference signal, and adjust the amplitude of the radio frequency reference signal according to the amplitude control signal to generate a radio frequency control signal for controlling the output power of the radio frequency power amplifier.

7. The radio frequency power supply sampling and control circuit as described in any one of claims 1-5, characterized in that, The first given signal includes a power given signal that maintains a corresponding power given value in different time intervals and undergoes a step change between adjacent time intervals; When the second feedback signal does not meet the reflection limiting condition, the first adjustment branch is used to continuously adjust the first adjustment signal according to the deviation between the power setpoint signal and the first feedback signal, so that the incident power represented by the first feedback signal follows the change of the corresponding power setpoint value in each of the time intervals.

8. The radio frequency power supply sampling and control circuit as described in any one of claims 1-5, characterized in that, The sampling unit includes a current sampling unit, a voltage sampling unit, a calibration unit, and a detection unit; The current sampling unit is used to collect the radio frequency current in the output circuit of the radio frequency power supply and generate a radio frequency current sampling signal. The voltage sampling unit is used to acquire the radio frequency voltage in the output circuit of the radio frequency power supply and generate a radio frequency voltage sampling signal; The calibration unit is used to calibrate at least one of the phase relationship and amplitude relationship between the radio frequency current sampling signal and the radio frequency voltage sampling signal; The detection unit is used to perform detection processing based on the calibrated radio frequency current sampling signal and the radio frequency voltage sampling signal to generate the first feedback signal and the second feedback signal.

9. A radio frequency power supply, characterized in that, Includes the radio frequency power sampling and control circuit as described in any one of claims 1-8.

10. A method for sampling and controlling radio frequency power supply, characterized in that, include: A first feedback signal characterizing the incident power and a second feedback signal characterizing the reflected power are generated based on the output signal of the radio frequency power supply. Based on the deviation between the first given signal and the first feedback signal, continuous-time simulation adjustment is performed to generate the first adjustment signal; Based on the deviation between the second given signal and the second feedback signal, continuous-time simulation adjustment is performed to generate a second adjustment signal; Based on the first adjustment signal and the second adjustment signal, cross-limiting processing is performed on the signal at the amplitude control node; The cross-limiting processing includes: When the second feedback signal does not meet the reflection limiting condition, the signal at the amplitude control node is adjusted by the first limiting branch according to the first adjustment signal; when the second feedback signal meets the reflection limiting condition, the signal at the amplitude control node is clamped by the second limiting branch according to the second adjustment signal to generate an amplitude control signal for adjusting the output power of the RF power amplifier.

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