Improved class d power amplifier, power amplifier control method, radio frequency power supply, and power supply method

Abstract

The present application relates to the technical field of radio frequency power supplies, and to an improved class D power amplifier, a power amplifier control method, a radio frequency power supply, and a power supply method, for use in solving the problem of impedance matching. A circuit at an output end of the class D power amplifier comprises multiple stages of LC resonant circuits; the multiple stages of LC resonant circuits comprise at least one stage of LC resonant circuit in which a controlled switch is configured in two ways, i.e., connected in parallel to an inductor and connected in series to a capacitor; the LC resonant circuits connected to the class D power amplifier are controlled by controlling the switch state of the controlled switch, to perform output impedance matching of the class D power amplifier. According to the present application, related inductors and capacitors are enabled and shielded on the basis of power output requirements, to form LC single-stage or multi-stage resonant topology meeting different requirements, thereby achieving impedance matching of the class D power amplifier.

Description

Improved Class D power amplifier, power amplifier control method, radio frequency power supply and power supply method Technical Field

[0001] The present application belongs to the field of radio frequency power supply technology, and specifically relates to an improved Class D power amplifier, a power amplifier control method, a radio frequency power supply, and a power supply method. Background Art

[0002] RF power supplies utilize different power amplifiers and corresponding topologies for different frequency domains. Class D amplifiers are typically used in conjunction with LC-based topologies. To suppress and filter out higher-order harmonics and perform impedance matching, smoothing the output power amplifier signal to meet usability requirements and avoiding signal anomalies such as ringing, oscillation, overshoot, and phase drift, a multi-stage LC resonant circuit is often employed.

[0003] The problems with existing resonant topologies are:

[0004] The resonant architecture is too rigid. While multi-stage resonant designs can effectively smooth the output signal, the passband is limited by the number of stages. Once the number of stages is determined, the passband is also relatively fixed. This results in poor bandwidth selectivity, and the overly limited frequency band also makes it difficult to adapt Class D amplifiers and corresponding topologies.

[0005] Summary of the Invention

[0006] In view of the above analysis, the present application aims to disclose an improved Class D power amplifier, a power amplifier control method, a radio frequency power supply and a power supply method, which dynamically adjusts the number of stages of the LC topology to provide a resonant network that meets the output requirements of the Class D power amplifier and solves the impedance matching problem.

[0007] One aspect of the present application discloses an improved Class D power amplifier. The circuit at the output end of the Class D power amplifier includes a multi-stage LC resonant circuit. The multi-stage LC resonant circuit includes at least one LC resonant circuit configured with a controlled switch in both a parallel inductor and a series capacitor. By controlling the switching state of the controlled switch, the LC resonant circuit connected to the Class D power amplifier is controlled to perform output impedance matching of the Class D power amplifier.

[0008] Furthermore, the multi-stage LC resonant circuit and the PWM controller of the class D power amplifier are respectively connected to the PID controller; the PWM controller is connected to the bridge structure of the class D power amplifier, and the bridge structure is further connected to the load through the multi-stage LC resonant circuit;

[0009] The PID controller changes the number of LC resonant circuit stages connected to the class D power amplifier by controlling the switching states of the controlled switches in the multi-stage LC resonant circuit to form a matching network corresponding to the output power;

[0010] The PID controller controls the output signal of the PWM controller, thereby controlling the duty cycle of each switch tube of the bridge structure to achieve control of the output power.

[0011] Furthermore, a code selector is included between the PID controller and the multi-stage LC resonant circuit;

[0012] The input end of the code selector is connected to the control code output by the PID controller;

[0013] The output end of the code selector is connected to each control end of the controlled switch in the multi-stage LC resonant circuit respectively;

[0014] The code selector selects a code according to the control code output by the PID controller, forms a switch control amount corresponding to the control code, and outputs the switch control amount to the corresponding controlled switch control end in the multi-stage LC resonant circuit through the output end.

[0015] Furthermore, the multi-stage LC resonant circuit includes an LC resonant circuit in which each stage of the controlled switch is configured in two ways: a parallel inductor and a series capacitor, and includes an inductor L, a capacitor C, a first controlled switch and a second controlled switch; wherein,

[0016] The inductor L is connected in parallel with the first controlled switch, and the inductor L, the second controlled switch and the capacitor C are connected in series in sequence, and then grounded through the end of the capacitor C that is not connected to the second controlled switch;

[0017] The port of the inductor L connected to the second controlled switch serves as the output end of the LC resonant circuit of this stage; and the other port of the inductor L serves as the input end of the LC resonant circuit of this stage.

[0018] Furthermore, the multi-stage LC resonant circuit includes an LC resonant circuit in which each stage of the controlled switch is configured in two ways: a parallel inductor and a series capacitor, and includes an inductor L, a capacitor C, a first controlled switch and a second controlled switch; wherein,

[0019] The inductor L is connected in parallel with the first controlled switch, and the inductor L, the capacitor C and the second controlled switch are connected in series in sequence, and then grounded through the end of the second controlled switch that is not connected to the capacitor C;

[0020] The port of the inductor L connected to the second controlled switch serves as the output port of the LC resonant circuit of this stage; and the other port of the inductor L serves as the input port of the LC resonant circuit of this stage.

[0021] Furthermore, the first controlled switch and the second controlled switch are semiconductor switch tubes including IGBT and SIC.

[0022] Furthermore, in the LC resonant circuit in which the controlled switches are configured in both parallel inductance and series capacitance modes, the control ends of the first controlled switch and the second controlled switch are respectively connected to one port of the output end of the code selector; and the number of ports at the output end of the code selector is twice the number of the LC resonant circuit.

[0023] Furthermore, in the LC resonant circuit in which the controlled switches are configured in both parallel inductance and series capacitance modes, the control ends of the first controlled switch and the second controlled switch are connected together and then connected to a port of the output end of the code selector; the number of ports at the output end of the code selector is the same as the number of the LC resonant circuit.

[0024] Another aspect of the present application further discloses a control method for an improved Class D power amplifier, comprising:

[0025] The PWM controller of the Class D power amplifier is controlled by PID to control the duty cycle of each switch tube in the bridge structure to control the output power;

[0026] At the same time, the switching state of the controlled switch in the multi-stage LC resonant circuit in the Class D power amplifier is controlled by PID, the number of LC resonant circuits connected to the Class D power amplifier is changed, and a matching network corresponding to the output power is formed for impedance matching;

[0027] The class D power amplifier is the improved class D power amplifier as described above.

[0028] Furthermore, the method of controlling the switching state of a controlled switch in a multi-stage LC resonant circuit in a class D power amplifier by PID, changing the number of LC resonant circuit stages connected to the class D power amplifier, and forming a matching network corresponding to the output power for impedance matching includes:

[0029] The PID controller generates a set of control codes corresponding to the output power according to the duty cycle of each switch tube in the controlled bridge structure;

[0030] The PID controller outputs the control code to the code selector;

[0031] The code selector selects the code according to the control code output by the PID controller to form the switch control quantity corresponding to the control code;

[0032] The switch control quantity is output to the corresponding controlled switch control terminal in the multi-stage LC resonant circuit, controlling the LC resonant circuit connected to the class D power amplifier to achieve output impedance matching of the class D power amplifier.

[0033] Another aspect of the present application further discloses a radio frequency power supply, which includes the improved class D power amplifier described above.

[0034] Another aspect of the present application also discloses a power supply method of a radio frequency power supply. When supplying power, the radio frequency power supply adopts the control method of the improved class D power amplifier as described above to achieve impedance matching of the output power.

[0035] This application can achieve one of the following beneficial effects:

[0036] This application provides a resonant network that meets the output requirements of a Class D amplifier by dynamically adjusting the number of stages of the LC topology. Moreover, through the configuration of the code selector, the regulation of the resonant topology corresponding to the number of bits output by the code selector can be achieved; and only one set of control codes needs to be transmitted between the code selector and the PID, which is not restricted by the PID output pins, and is more flexible in circuit design. The topology structure can be directly modularized with the switching tube, and the connection with the code selector can be simpler. In response to the power output requirements, the inductors and capacitors related to shielding are enabled to form single-stage or multi-stage LC resonant topologies with different requirements, which helps to better meet the actual needs of the power amplifier stages and achieve impedance matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present application. Throughout the drawings, the same reference symbols denote the same components.

[0038] FIG1 is a schematic diagram showing the connection of a multi-stage LC resonant circuit of an improved Class D power amplifier in an embodiment of the present application;

[0039] FIG2 is a schematic diagram of an improved Class D power amplifier in an embodiment of the present application;

[0040] FIG3 is a schematic diagram of a single-stage LC resonant circuit connection in an embodiment of the present application;

[0041] FIG4 is a schematic diagram showing the connection of another single-stage LC resonant circuit in an embodiment of the present application;

[0042] FIG5 is a schematic diagram showing a connection between a class D power amplifier in which the control terminals of the first controlled switch and the second controlled switch are respectively connected to a code selector in an embodiment of the present application;

[0043] FIG6 is a schematic diagram showing a connection between the control ends of the first controlled switch and the second controlled switch in an embodiment of the present application and a class D power amplifier of a code selector after being connected together. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present application are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present application and are used together with the embodiments of the present application to illustrate the principles of the present application.

[0045] Example 1

[0046] One embodiment of the present application discloses an improved Class D power amplifier. The circuit at the output end of the Class D power amplifier includes a multi-stage LC resonant circuit. The multi-stage LC resonant circuit includes at least one LC resonant circuit configured with a controlled switch in both a parallel inductor and a series capacitor. By controlling the switching state of the controlled switch, the LC resonant circuit connected to the Class D power amplifier is controlled to perform output impedance matching of the Class D power amplifier.

[0047] As shown in FIG1 , in a specific embodiment of the present invention, a multi-stage LC resonant circuit includes N stages of first-type LC resonant circuits configured with controlled switches in both parallel inductors and series capacitors, and may also include M stages of second-type LC resonant circuits without controlled switches, where N, M ≥ 1. A control signal is output to each stage of the first-type LC resonant circuit to control the LC resonant circuit connected to the Class D power amplifier. Retaining the second-type LC resonant circuit without controlled switches can prevent damage to the Class D power amplifier due to extreme conditions such as drastic changes in the resonant parameters of the LC resonant circuit or short circuits in the event of a fault such as control confusion, thereby improving circuit reliability.

[0048] In this embodiment, the number of stages of the LC topology is dynamically adjusted by controlling the switching state of the controlled switch to provide a resonant network that meets the output requirements of the Class D power amplifier. This allows the impedance of the resonant network to match the power output requirements, thereby making the output power amplifier signal smoother and meeting the available requirements, avoiding signal anomalies such as ringing, oscillation, up and downshoot, and phase drift.

[0049] In a Class D amplifier, a PID controller is used to control the pulse width and frequency of the PWM signal output by the PWM controller, thereby controlling the duty cycle of each switch tube in the bridge structure of the Class D amplifier, thereby controlling the output power of the Class D amplifier.

[0050] For the Class D amplifier solution that uses a PID controller to control power output,

[0051] The multi-stage LC resonant circuit and the PWM controller of the class D power amplifier are respectively connected to the PID controller; the PWM controller is connected to the bridge structure of the class D power amplifier, and the bridge structure is further connected to the load through the multi-stage LC resonant circuit;

[0052] The PID controller changes the number of LC resonant circuit stages connected to the class D power amplifier by controlling the switching states of the controlled switches in the multi-stage LC resonant circuit to form a matching network corresponding to the output power;

[0053] The PID controller controls the output signal of the PWM controller, thereby controlling the duty cycle of each switch tube of the bridge structure to achieve control of the output power.

[0054] Since the number of controlled switches in a multi-stage LC resonant circuit increases as the number of stages increases, if a PID controller is used to directly control the controlled switches in the multi-stage LC resonant circuit, the number of output pins of the PID controller will increase, thereby increasing the design difficulty and cost.

[0055] In a preferred solution of this embodiment, a code selector is further included between the PID controller and the multi-stage LC resonant circuit;

[0056] The input end of the code selector is connected to the control code output by the PID controller;

[0057] The output end of the code selector is connected to each control end of the controlled switch in the multi-stage LC resonant circuit respectively;

[0058] The code selector selects a code according to the control code output by the PID controller, forms a switch control amount corresponding to the control code, and outputs the switch control amount to the corresponding controlled switch control end in the multi-stage LC resonant circuit through the output end.

[0059] The code selection is a decoding process of the control code. According to the agreed decoding rules, the control code is matched with the output quantity of each output end of the code selector; one control code corresponds to a group of output quantities, forming a control combination of controlled switches for the multi-stage LC resonant circuit.

[0060] By configuring a code selector, only one set of control codes needs to be transmitted between the code selector and the PID controller. The code selector selects the switch control value based on the control code and outputs it to the corresponding controlled switch control terminal in the multi-stage LC resonant circuit. This eliminates the limitations of the PID controller's output pins, making circuit design more flexible and reducing implementation costs.

[0061] FIG2 is a schematic diagram of an improved class D power amplifier controlled by a code selector.

[0062] Each stage of the multi-stage LC resonant circuit can employ various LC resonance modes, including LC series, LC parallel, or LC series-parallel. Regardless of the LC resonance mode employed, the circuit structure of the present embodiment, which employs both parallel inductor and series capacitor configurations to control the inductor L and capacitor C, thereby achieving a multi-stage LC resonant circuit whose resonance parameters match the output power bandwidth of the Class D amplifier, should be considered within the scope of protection under the design concept of this application.

[0063] In a preferred solution, as shown in FIG3 , the multi-stage LC resonant circuit includes an LC resonant circuit in which each stage is configured with a controlled switch in both a parallel inductor and a series capacitor.

[0064] It includes an inductor L, a capacitor C, a first controlled switch T1 and a second controlled switch T2; wherein,

[0065] The inductor L is connected in parallel with the first controlled switch T1, and the inductor L, the second controlled switch T2 and the capacitor C are connected in series in sequence, and then the end of the capacitor C that is not connected to the second controlled switch T2 is grounded;

[0066] The port of the inductor L connected to the second controlled switch T2 serves as the output end of the LC resonant circuit of this stage; the other port of the inductor L serves as the input end of the LC resonant circuit of this stage.

[0067] In addition, the inductor L, capacitor C, first controlled switch T1 and second controlled switch T2 included in the LC resonant circuit can be directly modularized and packaged, and the various levels can be connected and connected to the code selector through the packaged pins, making the connection simpler and more reliable.

[0068] In a preferred solution, as shown in FIG4 , the multi-stage LC resonant circuit includes an LC resonant circuit in which each stage is configured with a controlled switch in both a parallel inductor and a series capacitor.

[0069] It includes an inductor L, a capacitor C, a first controlled switch T1 and a second controlled switch T2; wherein,

[0070] The inductor L is connected in parallel with the first controlled switch T1, and the inductor L, the capacitor C and the second controlled switch T2 are connected in series in sequence, and then grounded through the end of the second controlled switch T2 that is not connected to the capacitor C;

[0071] The port of the inductor L connected to the second controlled switch T2 serves as the output end of the LC resonant circuit of this stage; the other port of the inductor L serves as the input end of the LC resonant circuit of this stage.

[0072] In addition, the inductor L, capacitor C, first controlled switch T1 and second controlled switch T2 included in the LC resonant circuit can be directly modularized and packaged, and the various levels can be connected and connected to the code selector through the packaged pins, making the connection simpler and more reliable.

[0073] In the above solution, the first and second controlled switches are semiconductor switching transistors including IGBTs and SICs. In principle, there is no specific restriction on whether the first and second controlled switches can be IGBTs, SICs, or other semiconductor switching transistors. As long as the voltage, current, and frequency tolerance requirements meet the design requirements, any selection is acceptable.

[0074] In a specific solution of this embodiment, in the LC resonant circuit configured with the controlled switch, the control ends of the first controlled switch and the second controlled switch are respectively connected to a port of the output end of the code selector; and the number of ports at the output end of the code selector is twice the number of the LC resonant circuit configured with the controlled switch.

[0075] FIG5 is a connection diagram showing that the control ends of the first controlled switch and the second controlled switch are respectively connected to the code selector.

[0076] That is, an N-stage LC resonant circuit configured with controlled switches in parallel inductors and series capacitors includes 2N controlled terminals, and the corresponding code selector also includes at least 2N output terminals; the code selector transmits a set of control codes of the input PID to select the code to obtain a 2N-bit switch control quantity, and outputs the switch control quantity corresponding to each output terminal to the corresponding controlled switch control terminal in the LC resonant circuit through the 2N output terminals to control the on and off of the switch, thereby realizing the access control of the capacitors and inductors of each stage of the LC resonant circuit and changing the resonance parameters.

[0077] In another specific solution of this embodiment, in the LC resonant circuit configured with the controlled switch, the control ends of the first controlled switch and the second controlled switch are connected together and then connected to a port of the output end of the code selector; the number of ports at the output end of the code selector is the same as the number of the LC resonant circuit configured with the controlled switch.

[0078] FIG6 is a schematic diagram showing the connection between the control ends of the first controlled switch and the second controlled switch and the code selector after being connected together.

[0079] That is, an N-stage LC resonant circuit configured with controlled switches in parallel inductors and series capacitors includes N controlled ends, and the corresponding code selector also includes at least N output ends; the code selector transmits a set of control codes of the input PID to select the code to obtain an N-bit switch control amount, and outputs the switch control amount corresponding to each output end to the corresponding controlled switch control end in the LC resonant circuit through the N output ends to control the on and off of the switch, thereby realizing the simultaneous access control of the capacitance and inductance of each stage of the LC resonant circuit and changing the resonance parameters.

[0080] Comparing the two specific solutions above, one controls the capacitance and inductance of each LC resonant circuit separately, which allows for more precise parameter control. However, this requires more control terminals, which in turn means more output terminals for the code selector, and places higher demands on the PID control and the code selector. The other controls the capacitance and inductance of each LC resonant circuit simultaneously, which requires fewer control terminals, which in turn means fewer output terminals for the code selector, and places lower demands on the PID control and the code selector, but also reduces the parameter control accuracy.

[0081] You can choose one of the two options based on actual needs.

[0082] Alternatively, the two solutions can be combined: the control terminals of the first and second controlled switches in certain LC resonant circuits are connected together and then connected to a port at the output of the code selector; the control terminals of the first and second controlled switches in certain LC resonant circuits are respectively connected to a port at the output of the code selector; the code selector selects a switch control variable corresponding to the control code transmitted by the PID, and controls the corresponding control terminals of the controlled switches in the two connected resonant circuits at each level to change the resonance parameters. This ensures that the parameter control accuracy is more closely matched to the number of bits output by the code selector, thereby achieving parameter control accuracy while minimizing the design difficulty and cost of the code selector.

[0083] In summary, the improved Class D power amplifier of the embodiment of the present application provides a resonant network that meets the output requirements of the Class D power amplifier by dynamically adjusting the number of stages of the LC topology. Moreover, through the configuration of the code selector, the regulation of the resonant topology corresponding to the number of bits output by the code selector can be achieved; and only one set of control codes needs to be transmitted between the code selector and the PID, which is not restricted by the PID output pin, and is more flexible in circuit design. The topology structure can be directly modularized with the switching tube, and the connection with the code selector can be simpler. In response to the power output requirements, the inductors and capacitors related to shielding are enabled to form single-stage or multi-stage LC resonant topologies with different requirements, which helps to better meet the actual requirements of the power amplifier stages and achieve impedance matching.

[0084] Example 2

[0085] One embodiment of the present application discloses a control method for an improved class-D power amplifier, wherein the improved class-D power amplifier is the improved class-D power amplifier described in the previous embodiment.

[0086] Among the control methods are:

[0087] The PWM controller of the Class D power amplifier is controlled by PID to control the duty cycle of each switch tube in the bridge structure to control the output power;

[0088] At the same time, the switching state of the controlled switch in the multi-stage LC resonant circuit in the class D power amplifier is controlled by PID, the number of LC resonant circuits connected to the class D power amplifier is changed, and a matching network corresponding to the output power is formed for impedance matching.

[0089] More specifically, in the process of controlling the switching state of a controlled switch in a multi-stage LC resonant circuit in a class D power amplifier through PID control, changing the number of LC resonant circuit stages connected to the class D power amplifier, and forming a matching network corresponding to the output power for impedance matching, the process includes:

[0090] The PID controller generates a set of control codes corresponding to the output power according to the duty cycle of each switch tube in the controlled bridge structure;

[0091] The PID controller outputs the control code to the code selector;

[0092] The code selector selects the code according to the control code output by the PID controller to form the switch control quantity corresponding to the control code;

[0093] The switch control quantity is output to the corresponding controlled switch control terminal in the multi-stage LC resonant circuit, controlling the LC resonant circuit connected to the class D power amplifier to achieve output impedance matching of the class D power amplifier.

[0094] The specific technical details and beneficial effects related to the improved Class D power amplifier in this embodiment can be referred to the first embodiment above, and will not be described in detail here.

[0095] Example 3

[0096] An embodiment of the present application discloses a radio frequency power supply, which includes the improved class D power amplifier described in the first embodiment.

[0097] The circuit at the output end of the improved Class D power amplifier includes a multi-stage LC resonant circuit, which includes at least one LC resonant circuit configured with a controlled switch in both a parallel inductor and a series capacitor. By controlling the switching state of the controlled switch, the LC resonant circuit connected to the Class D power amplifier is controlled to perform output impedance matching of the Class D power amplifier, so that the impedance of the resonant network matches the output power requirement of the radio frequency power supply.

[0098] The specific technical details and beneficial effects related to the improved Class D power amplifier in this embodiment can be referred to in Example 1, and will not be described in detail here.

[0099] Example 4

[0100] An embodiment of the present application discloses a power supply method of a radio frequency power supply; the radio frequency power supply is the radio frequency power supply including the improved class D power amplifier in embodiment three.

[0101] The power supply method of the radio frequency power supply includes:

[0102] The PWM controller of the Class D power amplifier is controlled by PID to control the duty cycle of each switch tube in the bridge structure to control the output power;

[0103] At the same time, the switching state of the controlled switch in the multi-stage LC resonant circuit in the class D power amplifier is controlled by PID, the number of LC resonant circuits connected to the class D power amplifier is changed, and a matching network corresponding to the output power is formed for impedance matching.

[0104] More specifically, in the process of controlling the switching state of a controlled switch in a multi-stage LC resonant circuit in a class D power amplifier through PID control, changing the number of LC resonant circuit stages connected to the class D power amplifier, and forming a matching network corresponding to the power output for impedance matching, the process includes:

[0105] The PID controller generates a set of control codes corresponding to the output power according to the duty cycle of each switch tube in the controlled bridge structure;

[0106] The PID controller outputs the control code to the code selector;

[0107] The code selector selects the code according to the control code output by the PID controller to form the switch control quantity corresponding to the control code;

[0108] The switch control quantity is output to the corresponding controlled switch control terminal in the multi-stage LC resonant circuit, controlling the LC resonant circuit connected to the class D power amplifier to achieve output impedance matching of the class D power amplifier.

[0109] The specific technical details and beneficial effects related to the improved Class D power amplifier in this embodiment can be referred to in Example 1, and will not be described in detail here.

[0110] The above is only a preferred specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in this application should be covered by the scope of protection of the present application.

Claims

1. An improved class D power amplifier, characterized in that: The circuit at the output end of the class D power amplifier includes a multi-stage LC resonant circuit, wherein the multi-stage LC resonant circuit includes at least one stage of an LC resonant circuit in which a controlled switch is configured in two ways: a parallel inductor and a series capacitor. By controlling the switching state of the controlled switch, the LC resonant circuit connected to the class D power amplifier is controlled to perform output impedance matching of the class D power amplifier.

2. The improved class D power amplifier according to claim 1, characterized in that: The multi-stage LC resonant circuit and the PWM controller of the class D power amplifier are respectively connected to the PID controller; the PWM controller is connected to the bridge structure of the class D power amplifier, and the bridge structure is connected to the load through the multi-stage LC resonant circuit; The PID controller changes the number of LC resonant circuits connected to the class D power amplifier by controlling the switch states of the controlled switches in the multi-stage LC resonant circuit to form a matching network corresponding to the output power; The PID controller controls the output signal of the PWM controller, thereby controlling the duty cycle of each switch tube of the bridge structure to achieve control of the output power.

3. The improved class D power amplifier according to claim 2, characterized in that: A code selector is also included between the PID controller and the multi-stage LC resonant circuit; The input end of the code selector is connected to the control code output by the PID controller; The output end of the code selector is connected to each control end of the controlled switch in the multi-stage LC resonant circuit respectively; The code selector selects a code according to the control code output by the PID controller to form a switch control amount corresponding to the control code, and outputs the switch control amount to the corresponding controlled switch control end in the multi-stage LC resonant circuit through the output end.

4. The improved class D power amplifier according to claim 3, characterized in that: The multi-stage LC resonant circuit includes an LC resonant circuit in which each stage of the controlled switch is configured in two ways: a parallel inductor and a series capacitor, and includes an inductor L, a capacitor C, a first controlled switch and a second controlled switch; wherein, The inductor L is connected in parallel with the first controlled switch, and the inductor L, the second controlled switch and the capacitor C are connected in series in sequence. Grounding through the end of the capacitor C that is not connected to the second controlled switch; The port of the inductor L connected to the second controlled switch serves as the output end of the LC resonant circuit of this stage; and the other port of the inductor L serves as the input end of the LC resonant circuit of this stage.

5. The improved class D power amplifier according to claim 3, characterized in that: The multi-stage LC resonant circuit includes an LC resonant circuit in which each stage of the controlled switch is configured in two ways: a parallel inductor and a series capacitor, and includes an inductor L, a capacitor C, a first controlled switch and a second controlled switch; wherein, The inductor L is connected in parallel with the first controlled switch, and the inductor L, the capacitor C and the second controlled switch are connected in series in sequence, and then grounded through the end of the second controlled switch that is not connected to the capacitor C; The port of the inductor L connected to the second controlled switch serves as the output end of the LC resonant circuit of this stage; and the other port of the inductor L serves as the input end of the LC resonant circuit of this stage.

6. The improved class D power amplifier according to claim 4 or 5, characterized in that: The first controlled switch and the second controlled switch are semiconductor switch tubes including IGBT and SIC.

7. The improved class D power amplifier according to claim 6, characterized in that: In the LC resonant circuit in which the controlled switches are configured in both parallel inductance and series capacitance modes, the control ends of the first controlled switch and the second controlled switch are respectively connected to a port of the output end of the code selector; the number of ports at the output end of the code selector is twice the number of the LC resonant circuit.

8. The improved class D power amplifier according to claim 6, characterized in that: In the LC resonant circuit in which the controlled switches are configured in both parallel inductance and series capacitance modes, the control ends of the first controlled switch and the second controlled switch are connected together and then connected to a port of the output end of the code selector; the number of ports at the output end of the code selector is the same as the number of the LC resonant circuit.

9. A control method for an improved class D power amplifier, characterized in that: include: The PWM controller of the Class D power amplifier is controlled by PID to control the duty cycle of each switch tube in the bridge structure to control the output power; At the same time, the switching state of the controlled switch in the multi-stage LC resonant circuit in the class D power amplifier is controlled by PID, the number of stages of the LC resonant circuit connected to the class D power amplifier is changed, and a matching network corresponding to the output power is formed for impedance matching; The class D power amplifier is an improved class D power amplifier as described in any one of claims 1-8.

10. The control method of the improved class D power amplifier according to claim 9, characterized in that: The method controls the switch state of a controlled switch in a multi-stage LC resonant circuit in a class D power amplifier by PID, changes the number of stages of the LC resonant circuit connected to the class D power amplifier, and forms a matching network corresponding to the output power for impedance matching, including: The PID controller generates a set of control codes corresponding to the output power according to the duty cycle of each switch tube of the controlled bridge structure; The PID controller outputs the control code to the code selector; The code selector selects the code according to the control code output by the PID controller to form a switch control quantity corresponding to the control code; The switch control quantity is output to the corresponding controlled switch control terminal in the multi-stage LC resonant circuit, and controls the LC resonant circuit connected to the class D power amplifier to achieve output impedance matching of the class D power amplifier.

11. A radio frequency power supply, characterized in that: The radio frequency power supply includes the improved class D power amplifier as described in any one of claims 1-8.

12. A method for supplying power to a radio frequency power source, characterized in that: When supplying power, the radio frequency power supply adopts the control method of the improved class D power amplifier as claimed in claim 9 or 10 to achieve impedance matching of the output power.

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