Capacitance switching circuit, radio frequency amplification circuit and radio frequency front end module

Abstract

The application discloses a capacitor switching circuit, a radio frequency amplification circuit and a radio frequency front end module. The capacitor switching circuit comprises at least one capacitor switching unit arranged between a first connection end and a second connection end; each capacitor switching unit comprises a first capacitor, a second capacitor and a switching switch; a first end of the first capacitor is connected with the first connection end, a second end of the first capacitor is connected with a first end of the second capacitor, and a second end of the second capacitor is connected with the second connection end; a first end of the switching switch is connected with the second end of the first capacitor, and a second end of the switching switch is grounded. In the scheme, when the switching switch is turned off, two capacitors in the capacitor switching unit are connected between the two connection ends, and the performance of the circuit between the two connection ends is adjusted by using the capacitance value of the connected capacitors; when the switching switch is turned on, each connection end is grounded through one capacitor, and the performance of the circuit where the connection end is located is ensured by using a single capacitor.

Description

Technical Field

[0001] This invention relates to the field of radio frequency communication technology, and in particular to a capacitor switching circuit, a radio frequency amplifier circuit, and a radio frequency front-end module. Background Technology

[0002] Current radio frequency (RF) systems have wide applications in fields such as communication, navigation, radio astronomy, and electronic warfare. RF amplifier circuits are crucial components of RF systems, primarily used to amplify low-power RF signals before transmitting them via antennas for information communication. In RF amplifier circuits, to ensure adequate overall performance, capacitor values ​​often need to be switched. However, existing circuits suffer from limitations in effectively switching capacitor values ​​to meet functional requirements, thus impacting overall circuit performance. Summary of the Invention

[0003] This invention provides a capacitor switching circuit, an RF amplifier circuit, and an RF front-end module to solve the problem that the capacitor value of existing circuits cannot be effectively switched to meet their functional requirements, thus affecting the overall performance of the circuit.

[0004] This invention provides a capacitor switching circuit, including at least one capacitor switching unit disposed between a first connection terminal and a second connection terminal; Each of the capacitor switching units includes a first capacitor, a second capacitor, and a switching switch; The first terminal of the first capacitor is connected to the first connection terminal, the second terminal of the first capacitor is connected to the first terminal of the second capacitor, and the second terminal of the second capacitor is connected to the second connection terminal. The first terminal of the switching switch is connected to the second terminal of the first capacitor, and the second terminal of the switching switch is grounded.

[0005] Preferably, both the first connection terminal and the second connection terminal are non-grounded terminals.

[0006] Preferably, the switching switch is a first MOSFET, the gate of the first MOSFET is connected to the control power supply terminal, the drain of the first MOSFET is connected to the second terminal of the first capacitor, and the source of the first MOSFET is grounded.

[0007] This invention provides a radio frequency amplifier circuit, which has a first node and a second node, and at least one component is provided on the first node and the second node; The radio frequency amplifier circuit also includes the capacitor switching circuit mentioned above, with the first connection terminal of the capacitor switching circuit coupled to the first node and the second connection terminal of the capacitor switching circuit coupled to the second node.

[0008] Preferably, the radio frequency amplifier circuit includes an amplifying transistor and a bias circuit; The input terminal of the amplifying transistor is coupled to the signal input terminal, and the first node is provided between the input terminal of the amplifying transistor and the signal input terminal; One end of the bias circuit is coupled to the input terminal of the amplifying transistor, and the bias circuit is provided with the second node; The radio frequency amplifier circuit also includes a third capacitor disposed between the first node and the second node.

[0009] Preferably, the capacitor switching circuit is configured to control the switching state of at least one of the switching switches according to the operating frequency band of the radio frequency amplifier circuit.

[0010] Preferably, the capacitor switching circuit is configured to determine the number of switching switches in the off state in the capacitor switching circuit according to the operating frequency band of the radio frequency amplifier circuit.

[0011] Preferably, when the capacitor switching circuit includes a capacitor switching unit, the capacitor switching circuit is configured such that the operating frequency band of the RF amplifier circuit is a first frequency band, and the switching state of the switching switch is an ON state; the operating frequency band of the RF amplifier circuit is a second frequency band, and the switching state of the switching switch is an OFF state; the first frequency band is less than the second frequency band.

[0012] Preferably, the bias circuit includes a bias transistor and a bias resistor; The first end of the bias resistor is connected to the bias transistor, and the second end of the bias resistor is coupled to the input terminal of the amplifying transistor. The second node is provided between the bias transistor and the first terminal of the bias resistor.

[0013] Preferably, the radio frequency amplifier circuit further includes a DC blocking capacitor, the first end of which is coupled to the signal input terminal, and the second end of which is coupled to the input terminal of the amplifier transistor; The second end of the bias resistor is coupled to the second end of the DC blocking capacitor; The first node is provided between the signal input terminal and the first terminal of the DC blocking capacitor.

[0014] Preferably, the bias transistor is a bias MOS transistor, the gate of the bias MOS transistor is connected to the bias power supply terminal, the drain of the bias MOS transistor is connected to the power supply terminal, and the source of the bias MOS transistor is connected to the bias resistor. Alternatively, the bias transistor is a bias BJT, with its base connected to the bias power supply terminal, its collector connected to the power supply terminal, and its emitter connected to the bias resistor.

[0015] A radio frequency front-end module includes the above-mentioned capacitor switching circuit, or includes the above-mentioned radio frequency amplifier circuit.

[0016] The aforementioned capacitor switching circuit, RF amplifier circuit, and RF front-end module connect a first capacitor and a second capacitor in series between a first connection terminal and a second connection terminal. A switching switch is used, with one end coupled between the first and second capacitors and the other end grounded. When the switching switch is open, the two capacitors in the capacitor switching unit are connected between the two connection terminals. When the switching switch is on, each connection terminal is grounded through a capacitor. The capacitance value connected to the capacitor switching circuit is used to adjust the required capacitance value between the two connection terminals. This effectively switches the capacitance value presented by the capacitor switching circuit, thereby ensuring the overall performance of the circuit. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a circuit diagram of a capacitor switching circuit in one embodiment of the present invention; Figure 2 This is another circuit diagram of the capacitor switching circuit in one embodiment of the present invention; Figure 3 This is a circuit diagram of a radio frequency amplifier circuit in one embodiment of the present invention; Figure 4 This is another circuit diagram of the radio frequency amplifier circuit in one embodiment of the present invention; Figure 5 This is another circuit diagram of the radio frequency amplifier circuit in one embodiment of the present invention; Figure 6 This is another circuit diagram of the radio frequency amplifier circuit in one embodiment of the present invention; Figure 7 This is another circuit diagram of the radio frequency amplifier circuit in one embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be understood that the invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0021] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0022] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0023] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0024] To fully understand this invention, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by this invention. Preferred embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0025] This invention provides a capacitor switching circuit 1, such as... Figure 1 and Figure 2 As shown, it includes at least one capacitor switching unit 11 disposed between the first connection terminal A and the second connection terminal B; Each capacitor switching unit 11 includes a first capacitor C11, a second capacitor C12, and a switching switch K11; The first terminal of the first capacitor C11 is connected to the first connection terminal A, the second terminal of the first capacitor C11 is connected to the first terminal of the second capacitor C12, and the second terminal of the second capacitor C12 is connected to the second connection terminal B. The first terminal of the switch K11 is connected to the second terminal of the first capacitor C11, and the second terminal of the switch K11 is grounded.

[0026] Among them, capacitor switching circuit 1 is a circuit that can realize capacitor switching. Capacitor switching unit 11 refers to a single unit that can realize the capacitor switching function. First connection terminal A and second connection terminal B refer to the two connection terminals of capacitor switching circuit 1 that connect to other circuits.

[0027] As an example, such as Figure 1As shown, the capacitor switching circuit 1 includes a capacitor switching unit 11 disposed between a first connection terminal A and a second connection terminal B. The capacitor switching unit 11 includes a first capacitor C11, a second capacitor C12, and a switching switch K11. The first end of the first capacitor C11 is connected to the first connection terminal A, the second end of the first capacitor C11 is connected to the first end of the second capacitor C12, and the second end of the second capacitor C12 is connected to the second connection terminal B. The first end of the switching switch K11 is connected to the second end of the first capacitor C11, and the second end of the switching switch K11 is grounded. That is, the first capacitor C11 and the second capacitor C12 are connected in series between the first connection terminal A and the second connection terminal B; the first end of the switching switch K11 is coupled to the connection node between the second end of the first capacitor C11 and the first end of the second capacitor C12, and the second end of the switching switch K11 is grounded. In this example, when the switch K11 is open, the first capacitor C11 and the second capacitor C12 are connected in series between the first connection terminal A and the second connection terminal B. The capacitance between the two connection terminals is the sum of the capacitance values ​​of the first capacitor C11 and the second capacitor C12. When the switch K11 is closed, the first connection terminal A is grounded through the first capacitor C11. The capacitance between the first connection terminal A and ground is the capacitance value of the first capacitor C11. At this time, the function of the first capacitor C11 is determined according to the position of the first connection terminal A. The second connection terminal B is grounded through the second capacitor C12. The capacitance between the second connection terminal B and ground is the capacitance value of the second capacitor C12. At this time, the function of the second capacitor C12 is determined according to the position of the second connection terminal B.

[0028] As an example, such as Figure 2 As shown, the capacitor switching circuit 1 includes at least two capacitor switching units 11 disposed between the first connection terminal A and the second connection terminal B. The two capacitor switching units 11 disposed between the first connection terminal A and the second connection terminal B can control the switching state of the switching switch K11 in the capacitor switching unit 11 to determine whether it is necessary to connect at least two capacitor switching units 11 between the two connection terminals to adjust the capacitance value between the two connection terminals. For example, the first capacitor switching unit 11 includes a first capacitor C11, a second capacitor C12, and a switching switch K11; the second capacitor switching unit 11 includes a first capacitor C21, a second capacitor C22, and a switching switch K21. When switching switch K11 is off and switching switch K21 is on, the capacitance between the two terminals is C11 + C12; when switching switch K11 is on and switching switch K21 is off, the capacitance between the two terminals is C21 + C22; when both switching switches K11 and K21 are off, the capacitance between the two terminals is C11 + C12 + C21 + C22; and when both switching switches K11 and K21 are on, the capacitance between the two terminals is 0.

[0029] In this embodiment, the first capacitor C11 and the second capacitor C12 are connected in series between the first connection terminal A and the second connection terminal B. A switching switch K11 is used, with one end coupled between the first capacitor C11 and the second capacitor C12 and the other end grounded. When the switching switch K11 is open, the two capacitors in the capacitor switching unit 11 are connected between the two connection terminals. The capacitance value connected to the capacitor switching circuit 1 is used to adjust the capacitance value between the two connection terminals, thereby optimizing the performance of the circuit in which the capacitor switching circuit 1 is located. When the switching switch K11 is on, each connection terminal is grounded through a capacitor, and a single capacitor meets the capacitance value required by its connection terminal, thereby ensuring the performance of the circuit in which it is located. For example, when the capacitor switching circuit 1 is applied to the bias circuit 2 of a power amplifier, the capacitor switching circuit can be used as a linear compensation unit. The switching switch K11 can be turned on or off according to the operating frequency band of the power amplifier to adjust the capacitance value connected between the two connection terminals, thereby improving the power-added efficiency and linearity of the power amplifier. For example, when the capacitor switching unit 11 is used in the matching circuit, the switching switch K11 can be turned on or off according to the capacitance value required during the operation of the matching circuit, thereby adjusting the capacitance value between the two connection terminals and ensuring the performance of the matching circuit.

[0030] In one embodiment, either the first connection terminal A or the second connection terminal B is a non-grounded terminal, while the other is a grounded terminal. For example, if the first connection terminal A is a non-grounded terminal and the second connection terminal B is a grounded terminal, then if the switch K11 is open, the first connection terminal A is grounded through the first capacitor C11 and the second capacitor C12; if the switch K11 is closed, the first connection terminal A is grounded through the first capacitor C11. This allows the switch K11 to adjust the capacitance value from the first connection terminal A to ground, thereby ensuring the performance of the circuit containing the first connection terminal A. Here, a non-grounded terminal is any connection terminal other than a grounded terminal.

[0031] Furthermore, both the first connection terminal A and the second connection terminal B are non-grounded terminals.

[0032] As an example, when both the first connection terminal A and the second connection terminal B are non-grounded, neither the first connection terminal A nor the second connection terminal B is grounded. In order to ensure circuit performance, at least one capacitor switching unit 11 can be connected in parallel between the first connection terminal A and the second connection terminal B. Since each capacitor switching unit 11 includes a first capacitor C11 and a second capacitor C12 connected in series, and the connection node between the first capacitor C11 and the second capacitor C12 is grounded through a switching switch K11, each capacitor switching unit 11 is equivalent to providing a grounding path for the two non-grounded terminals, the first connection terminal A and the second connection terminal B.

[0033] As an example, when both the first connection terminal A and the second connection terminal B are non-grounded terminals, at least one component X1 is provided between the first connection terminal A and the second connection terminal B. Depending on the circuit where the at least one component X1 is located, when it is necessary to connect the first capacitor C11 and the second capacitor C12 between the two non-grounded terminals of the circuit, the switching switch K11 can be controlled to be turned off to adjust the capacitance value at both ends of the circuit where the two non-grounded terminals are located, thereby ensuring the performance of the circuit. When it is not necessary to connect the first capacitor C11 and the second capacitor C12 between the two non-grounded terminals of the circuit, the switching switch K11 can be controlled to be turned on so that each of the two non-grounded terminals is grounded through a capacitor, and a single capacitor is used to meet the capacitance value required by its connection terminal, thereby ensuring the performance of the circuit.

[0034] In one embodiment, the switching switch K11 is a first MOSFET, the gate of the first MOSFET is connected to the control power supply terminal, the drain of the first MOSFET is connected to the second terminal of the first capacitor C11, and the source of the first MOSFET is grounded.

[0035] As an example, switch K11 is a first MOSFET. The gate of the first MOSFET is connected to the control power supply terminal, and the drain of the first MOSFET is coupled to the connection node between the first capacitor C11 and the second capacitor C12. That is, the drain of the first MOSFET is connected to both the second terminal of the first capacitor C11 and the first terminal of the second capacitor C12, and the source of the first MOSFET is grounded. In this example, the conduction status of the drain and source of the first MOSFET can be determined based on the control voltage received by the gate of the first MOSFET from the control power supply terminal, thereby achieving the effect of controlling the first MOSFET to be turned on or off.

[0036] This invention provides a radio frequency amplifier circuit, such as... Figure 3 As shown, the radio frequency amplifier circuit has a first node P1 and a second node P2, and at least one component X1 is provided on the first node P1 and the second node P2. The radio frequency amplifier circuit also includes the capacitor switching circuit 1 mentioned above. The first connection terminal A of the capacitor switching circuit 1 is coupled to the first node P1, and the second connection terminal B of the capacitor switching circuit 1 is coupled to the second node P2.

[0037] Among them, the first node P1 and the second node P2 are two nodes in the radio frequency amplifier circuit.

[0038] As an example, the RF amplifier circuit includes a first node P1 and a second node P2. At least one component X1 is located between the first node P1 and the second node P2. That is, the first node P1 and the second node P2 are two nodes in a circuit formed by the cooperation of at least one component X1, or two ports of a circuit formed by the cooperation of at least one component X1. The component X1 here includes, but is not limited to, at least any one of a resistor, inductor, capacitor, or transistor in series and / or parallel combination. The at least one component X1 can be arranged in series and / or parallel according to actual needs.

[0039] In this embodiment, the RF amplifier circuit further includes the capacitor switching circuit 1 described in the previous embodiment, which includes at least one capacitor switching unit 11 disposed between the first connection terminal A and the second connection terminal B. Specifically, the first connection terminal A of the capacitor switching circuit 1 is coupled to the first node P1, and the second connection terminal B of the switching circuit 1 is coupled to the second node P2. Each capacitor switching unit 11 includes a first capacitor C11 and a second capacitor C12 connected in series. The connection node between the first capacitor C11 and the second capacitor C12 is grounded through a switching switch K11. When the switching switch K11 is open, the first capacitor C11 and the second capacitor C12 are connected in series between the first node P1 and the second node P2 of the circuit formed by at least one component X1, thereby increasing the capacitance value between the two nodes of the circuit formed by at least one component X1. At this time, the increased capacitance value is the sum of the capacitance values ​​of the first capacitor C11 and the second capacitor C12, so as to ensure the performance of the circuit formed by at least one component X1, for example, to ensure the impedance matching degree or linearity of the circuit formed by at least one component X1. When the switch K11 is turned on, in the circuit formed by at least one component X1, the first node P1 is grounded through the first capacitor C11, and the capacitance between the first node P1 and ground is the capacitance value of the first capacitor C11; the second node P2 is grounded through the second capacitor C12, and the capacitance between the second node P2 and ground is the capacitance value of the second capacitor C12. In other words, when the switch K11 is turned on, each of the two nodes in the circuit formed by at least one component X1 is grounded through a capacitor. The grounded capacitors meet the capacitance requirements of their connection terminals, thereby ensuring the performance of the circuit. For example, the grounded capacitors can be used to achieve decoupling, filtering, matching, or other effects.

[0040] In one embodiment, such as Figure 4 As shown, the radio frequency amplifier circuit includes an amplifying transistor M1 and a bias circuit 2; The input terminal of the amplifying transistor M1 is coupled to the signal input terminal In, and a first node P1 is provided between the input terminal of the amplifying transistor M1 and the signal input terminal In; One end of the bias circuit 2 is coupled to the input terminal of the amplifying transistor M1, and the bias circuit 2 is provided with a second node P2; The radio frequency amplifier circuit also includes a third capacitor C3 disposed between the first node P1 and the second node P2.

[0041] In this circuit, transistor M1 is the transistor that amplifies the signal in the radio frequency amplifier circuit. Bias circuit 2 provides bias current to transistor M1. Signal input terminal In is the input terminal of the radio frequency amplifier circuit, i.e., the port used to receive signals transmitted from external circuits.

[0042] As an example, the RF amplifier circuit includes an amplifying transistor M1 and a bias circuit 2. The input terminal of the amplifying transistor M1 is coupled to the signal input terminal In of the RF amplifier circuit, and a first node P1 is provided between the input terminal of the amplifying transistor M1 and the signal input terminal In of the RF amplifier circuit. One end of the bias circuit 2 is coupled to the input terminal of the amplifying transistor M1 to provide bias to the amplifying transistor M1, and a second node P2 is provided on the bias circuit 2. In this example, at least one component X1 exists between the first node P1 between the input terminal of the amplifying transistor M1 and the signal input terminal In of the RF amplifier circuit, and between the second node P2 on the bias circuit 2. Preferably, in this embodiment, the component X1 is a bias resistor R1 on the output path of the bias circuit 2. The bias circuit 2 is connected to the input terminal of the amplifying transistor M1 through the bias resistor R1 to provide a bias signal to the amplifying transistor; that is, the second node P2 is located on the connection path between the output node of the bias circuit 2 and the bias resistor R1.

[0043] In one specific embodiment, the compensation amount of the bias circuit 2 can be adjusted by changing the resistance value of the bias resistor R1, or by changing the capacitor switching circuit 1. Specifically, under normal operating conditions of the RF amplifier circuit, as the input RF signal increases, the RF input signal flows into the bias circuit 2 not only through the bias resistor R1, but also through the path (linear compensation unit) formed by the capacitor switching circuit 1 and the third capacitor C3, thus achieving linear compensation for the bias circuit 2 without affecting the circuit's static operating point. In this embodiment, the compensation amount of the bias circuit 2 is mainly adjusted by changing the capacitance value presented by the capacitor switching circuit 1. As an example, when the bias circuit 2 requires a larger linear compensation amount, the switching switch in the capacitor switching circuit 1 is turned off. At this time, the two capacitors of the capacitor switching circuit 1 are connected between the first node P1 and the second node P2. The RF input signal can flow into the bias circuit 2 not only through the bias resistor R1, but also through the capacitor switching circuit 1, thereby increasing the linear compensation amount of the bias circuit 2. When the bias circuit 2 does not require a large linear compensation, the switch 11 in the capacitor switching circuit 1 is turned on. At this time, the connection between the first node P1 and the second node P2 is broken, and the RF input signal cannot flow into the bias circuit 2 through the capacitor switching circuit 1. The RF input signal flowing into the bias circuit 2 is reduced. The first node P1 and the second node P2 are each grounded through a capacitor. At this time, the capacitor to ground of the first node P1 can play a matching role, and the capacitor to ground of the second node P1 can improve the AM-AM of the RF amplifier circuit. In this example, the RF amplifier circuit includes not only a third capacitor C3 disposed between the first node P1 and the second node P2, but also a capacitor switching circuit 1 with a first connection terminal A coupled to the first node P1 and a second connection terminal B coupled to the second node P2. That is, in this RF amplifier circuit, the third capacitor C3 and the capacitor switching circuit 1 are connected in parallel, both positioned between the first node P1 and the second node P2. They can control the switching switch K11 in the capacitor switching circuit 1 to turn on or off, determining whether it is necessary to connect the two capacitors in the capacitor switching circuit 1 between the first node P1 and the second node P2, adjusting the capacitance value between the first node P1 and the second node P2 of the RF amplifier circuit to ensure the performance of the RF amplifier circuit. For example, when switch K11 is open, the first capacitor C11 and the second capacitor C12 are connected in series between the first node P1 and the second node P2 of the RF amplifier circuit. The capacitance between the two nodes is the sum of the capacitances of the third capacitor C3, the first capacitor C11, and the second capacitor C12. When switch K11 is closed, the first capacitor C11 and the second capacitor C12 are not connected between the first node P1 and the second node P2 of the RF amplifier circuit. At this time, the capacitance between the two nodes is the capacitance of the third capacitor C3. The first node P1 is grounded through the first capacitor C11, and the second node P2 is grounded through the second capacitor C12. In this case, the first capacitor C11 from the first node P1 to ground can play a matching role, and the second capacitor C12 from the second node P1 to ground can improve the AM-AM of the RF amplifier circuit. As an example, a first node P1 is set between the input terminal of the amplifying transistor M1 and the signal input terminal In of the RF amplifier circuit. A second node P2 is set on the bias circuit 2. A third capacitor C3 and a capacitor switching circuit 1 are set between the first node P1 and the second node P2. When the switching switch K11 in the capacitor switching circuit 1 is turned on, the first capacitor C11 and the second capacitor C12 in the capacitor switching circuit 1 are not connected between the two nodes of the RF amplifier circuit, and the capacitance value between the two nodes is the capacitance value of the third capacitor C3. When the switching switch K11 in the capacitor switching circuit 1 is turned off, the first capacitor C11 and the second capacitor C12 in the capacitor switching circuit 1 are connected between the two nodes of the RF amplifier circuit. At this time, the capacitance value between the two nodes is the sum of the third capacitor C3, the first capacitor C11, and the second capacitor C12. That is to say, the switching switch K11 in the capacitor switching circuit 1 can be controlled to turn on or off, thereby adjusting the capacitance value of the two nodes in the RF amplifier circuit, and thus adjusting the linear compensation of the bias circuit 2, so as to improve the power-added efficiency and linearity of the RF amplifier circuit.

[0044] In one embodiment, the capacitor switching circuit 1 is configured to control the switching state of at least one switching switch K11 according to the operating frequency band of the radio frequency amplifier circuit.

[0045] As an example, a first node P1 is set between the input terminal of the amplifying transistor M1 and the signal input terminal In of the RF amplifier circuit. A second node P2 is set on the bias circuit 2. A third capacitor C3 and a capacitor switching circuit 1 are set between the first node P1 and the second node P2. At this time, the capacitor switching circuit 1 acts as a linear compensation unit. When the capacitance value of the third capacitor C3 between the two nodes cannot meet the capacitance value required by the operating frequency band of the RF amplifier circuit, the switching switch K11 in the capacitor switching circuit 1 can be turned on to connect the first capacitor C11 and the second capacitor C12 connected in series in the capacitor switching circuit 1 to the two nodes, thereby adjusting the linear compensation amount of the bias circuit 2 to improve the power-added efficiency and linearity of the RF amplifier circuit.

[0046] In this example, the switching state of at least one switching switch K11 can be controlled according to the operating frequency band of the RF amplifier circuit. Specifically, when the operating frequency band of the RF amplifier circuit is small and the linear compensation required by the bias circuit 2 is small, and when it is determined that the capacitance value connected to the RF amplifier circuit has met the requirements for ensuring its power-added efficiency and linearity, all switching switches K11 can be controlled to be in the on state, so that the capacitors in all capacitor switching units 11 are not connected to the two nodes of the RF amplifier circuit, thereby reducing the linear compensation of the bias circuit 2 of the RF amplifier circuit. When the operating frequency band of the RF amplifier circuit is large and the linear compensation required by the bias circuit 2 is large, and it is determined that the capacitor value connected to the RF amplifier circuit cannot meet the requirements of its power-added efficiency and linearity, the target capacitor value corresponding to the linear compensation required by the bias circuit 2 can be determined according to the operating frequency band of the RF amplifier circuit. The difference between the target capacitor value and the capacitance value of the third capacitor C3 can be determined as the capacitor value to be compensated. Then, according to the capacitor value to be compensated, the switching state of at least one switching switch K11 is controlled to be in the open state, so that the two capacitors corresponding to the switching switch K11 in the open state are connected between the two nodes of the RF amplifier circuit. The capacitor in at least one capacitor switching unit 11 is used to increase the linear compensation of the bias circuit 2, so as to improve the power-added efficiency and linearity of the RF amplifier circuit.

[0047] In one embodiment, the capacitor switching circuit 1 is configured to determine the number of switching switches K11 in the off state in the capacitor switching circuit 1 according to the operating frequency band of the radio frequency amplifier circuit.

[0048] In this example, the number of switching switches K11 in the off state in capacitor switching circuit 1 can be determined according to the operating frequency band of the RF amplifier circuit. The control process is as follows: When the operating frequency band of the RF amplifier circuit is small and the linear compensation required by the bias circuit 2 is small, it is determined that the capacitance value of the third capacitor C3 connected to the RF amplifier circuit is sufficient to ensure its power-added efficiency and linearity requirements. All switching switches K11 can be controlled to be in the on state, that is, the number of switching switches K11 in the off state in capacitor switching circuit 1 is controlled to be zero, so that the capacitors in all capacitor switching units 11 are not connected to the two nodes of the RF amplifier circuit, thereby reducing the linear compensation of the bias circuit 2 of the RF amplifier circuit. When the operating frequency band of the RF amplifier circuit is large and the linear compensation required by the bias circuit 2 is large, it is determined that the capacitance value connected to the RF amplifier circuit cannot meet the requirements of its power-added efficiency and linearity. According to the operating frequency band of the RF amplifier circuit, the target capacitance value corresponding to the linear compensation required by the bias circuit 2 can be determined. The difference between the target capacitance value and the capacitance value of the third capacitor C3 can be determined as the capacitance value to be compensated. The larger the capacitance value to be compensated, the more switching switches K11 in the capacitor switching circuit 1 are in the open state. When any switching switch K11 is in the open state, the two capacitors corresponding to the switching switch K11 are connected between the two nodes of the RF amplifier circuit. The capacitance in at least one capacitor switching unit 11 is used to increase the linear compensation of the bias circuit 2, so that the capacitance value between the two nodes in the RF amplifier circuit reaches the target capacitance value, thereby improving the power-added efficiency and linearity of the RF amplifier circuit.

[0049] For example, when the operating frequency band of the RF amplifier circuit is relatively small and the linear compensation required by the bias circuit 2 is small, and the third capacitor C3 connected between the two nodes of the RF amplifier circuit is sufficient to guarantee its power-added efficiency and linearity requirements, all switching switches K11 can be controlled to be in the on state. That is, the number of switching switches K11 in the capacitor switching circuit 1 that are in the off state is controlled to be zero, so that the capacitors in all capacitor switching units 11 are not connected to the two nodes of the RF amplifier circuit, thereby reducing the linear compensation required by the bias circuit 2 of the RF amplifier circuit. When the operating frequency band of the RF amplifier circuit is relatively large and the linear compensation required by the bias circuit 2 is large, the third capacitor C3 connected between the two nodes of the RF amplifier circuit cannot meet the requirements to guarantee its power-added efficiency and linearity. In this case, at least one switching switch K11 in the capacitor switching unit 11 needs to be controlled to be in the off state, so that its corresponding first capacitor C11 and second capacitor C12 can be connected to the RF amplifier circuit. The capacitors in at least one capacitor switching unit 11 are used to increase the linear compensation required by the bias circuit 2, thereby improving the power-added efficiency and linearity of the RF amplifier circuit. In this example, the higher the operating frequency band of the RF amplifier circuit, the more switching switches K11 in the capacitor switching circuit 1 are in the off state, resulting in a larger capacitance value between the first node P1 and the second node P2 of the RF amplifier circuit, thereby ensuring the power-added efficiency and linearity of the RF amplifier circuit.

[0050] like Figure 5 As shown, the capacitor switching circuit 1 between the two nodes connected to the RF amplifier circuit includes two capacitor switching units 11. The first capacitor switching unit 11 includes a first capacitor C11, a second capacitor C12 and a switching switch K11, and the sum of the capacitance values ​​of the two capacitors is C11+C12. The second capacitor switching unit 11 includes a first capacitor C21, a second capacitor C22 and a switching switch K21, and the sum of the capacitance values ​​of the two capacitors is C21+C22.

[0051] In the case where C11+C12=C21+C22, when the operating frequency of the RF amplifier circuit is less than the first threshold, it can be determined that the operating frequency of the RF amplifier circuit is small and the linear compensation required by the bias circuit 2 is small. Therefore, it can be determined that the number of switching switches K11 in the off state is 0. At this time, both switching switches K11 can be controlled to be in the on state, so that the capacitors in all capacitor switching units 11 are not connected to the two nodes of the RF amplifier circuit, thereby reducing the linear compensation of the bias circuit 2 of the RF amplifier circuit. When the operating frequency of the RF amplifier circuit is not less than the first threshold and the operating frequency of the RF amplifier circuit is less than the second threshold, it can be determined that the operating frequency of the RF amplifier circuit is relatively large and the linear compensation required by the bias circuit 2 is relatively large. It can be determined that the number of switching switches K11 in the off state is 1. It can be controlled that one of the two switching switches K11 is in the off state and the other is in the on state, so that C11 and C12 are connected between the two nodes of the RF amplifier circuit, or C21 and C22 are connected between the two nodes of the RF amplifier circuit. At this time, the capacitance value between the two nodes of the RF amplifier circuit is C3+C11+C12 (or C3+C21+C22), so as to increase the linear compensation of the bias circuit 2 by using the capacitance in one capacitor switching unit 11, so as to improve the power-added efficiency and linearity of the RF amplifier circuit. When the operating frequency of the RF amplifier circuit is not lower than the second threshold, at least two switching switches K11 can be controlled to be in the open state, so that C11, C12, C21, and C22 are all connected between two nodes of the RF amplifier circuit. At this time, the capacitance between the two nodes of the RF amplifier circuit is C3 + C11 + C12 + C21 + C22. This increases the linear compensation of the bias circuit 2 by utilizing the capacitance in the two capacitor switching units 11, thereby improving the power-added efficiency and linearity of the RF amplifier circuit. The first threshold and the second threshold are preset thresholds related to the operating frequency band, with the first threshold < the second threshold.

[0052] When C11+C12<C21+C22, when the operating frequency band of the radio frequency amplifier circuit is less than a first threshold, it can be determined that the operating frequency band of the radio frequency amplifier circuit is relatively small, and when the linear compensation amount required by the bias circuit 2 is relatively small, it can be determined that the number of switching switches K11 in an off state is 0, that is, both switching switches K11 are controlled to be in an on state, so that the capacitors in all capacitor switching units 11 are not connected to the two nodes of the radio frequency amplifier circuit, thereby reducing the linear compensation amount for the bias circuit 2 of the radio frequency amplifier circuit. When the operating frequency band of the radio frequency amplifier circuit is not less than the first threshold and less than a second threshold, C11 and C12 can be controlled to be connected between the two nodes of the radio frequency amplifier circuit, at this time, the capacitance value between the two nodes of the radio frequency amplifier circuit is C3+C11+C12, and the capacitors C11 and C12 are used to increase the linear compensation amount for the bias circuit 2, so that the capacitance value between the two nodes in the radio frequency amplifier circuit reaches the target capacitance value, so as to achieve the purpose of improving the power added efficiency and linearity of the radio frequency amplifier circuit. When the operating frequency band of the radio frequency amplifier circuit is not less than the second threshold and less than a third threshold, C21 and C22 can be controlled to be connected between the two nodes of the radio frequency amplifier circuit, at this time, the capacitance value between the two nodes of the radio frequency amplifier circuit is C3+C21+C22, and the capacitors C21 and C22 are used to increase the linear compensation amount for the bias circuit 2, so that the capacitance value between the two nodes in the radio frequency amplifier circuit reaches the target capacitance value, so as to achieve the purpose of improving the power added efficiency and linearity of the radio frequency amplifier circuit. When the operating frequency band of the radio frequency amplifier circuit is not less than the third threshold, at least two switching switches K11 can be controlled to be both in an off state, so that C11, C12, C21 and C22 are all connected between the two nodes of the radio frequency amplifier circuit, at this time, the capacitance value between the two nodes of the radio frequency amplifier circuit is C3+C11+C12+C21+C22, and the capacitors C11, C12, C21 and C22 are used to increase the linear compensation amount for the bias circuit 2, so that the capacitance value between the two nodes in the radio frequency amplifier circuit reaches the target capacitance value, so as to achieve the purpose of improving the power added efficiency and linearity of the radio frequency amplifier circuit. Wherein, the first threshold, the second threshold and the third threshold are preset thresholds related to the operating frequency band, and the first threshold < the second threshold < the third threshold.

[0053] In one embodiment, when the capacitor switching circuit 1 includes one capacitor switching unit 11, the capacitor switching circuit 1 is configured such that: when the operating frequency band of the radio frequency amplifier circuit is a first frequency band, the switching state of the switching switch K11 is an on state; when the operating frequency band of the radio frequency amplifier circuit is a second frequency band, the switching state of the switching switch K11 is an off state; and the first frequency band is smaller than the second frequency band.

[0054] The first frequency band and the second frequency band are two pre-set frequency bands. The first frequency band is shorter than the second frequency band. For example, the first frequency band is the N71 frequency band (i.e., 663-698MHz) and the second frequency band is the N28 frequency band (i.e., 703-748MHz).

[0055] As an example, when the capacitor switching circuit 1 includes a capacitor switching unit 11, the capacitor switching unit 11 includes a first capacitor C11, a second capacitor C12, and a switching switch K11; when the operating frequency band of the RF amplifier circuit is the first frequency band, it can be determined that the operating frequency band of the RF amplifier circuit is relatively small, and the linear compensation required by the bias circuit 2 is relatively small. It is determined that the capacitance value of the third capacitor C3 connected to the RF amplifier circuit has met the requirements for ensuring its power-added efficiency and linearity. The switching switch K11 in the capacitor switching unit 11 can be controlled to be in the on state, so that the first capacitor C11 and the second capacitor C12 are not connected to the two nodes of the RF amplifier circuit, thereby reducing the linear compensation of the bias circuit 2 of the RF amplifier circuit. When the operating frequency band of the RF amplifier circuit is the second frequency band, it can be assumed that the operating frequency band of the RF amplifier circuit is relatively large, and the linear compensation required by the bias circuit 2 is relatively large. It is determined that the capacitance value of the third capacitor C3 connected to the RF amplifier circuit cannot meet the requirements of ensuring its power-added efficiency and linearity. The switching switch K11 in the capacitor switching unit 11 can be controlled to be in the open state, so that the first capacitor C11 and the second capacitor C12 are connected to the two nodes of the RF amplifier circuit. The first capacitor C11 and the second capacitor C12 are used to increase the linear compensation of the bias circuit 2, so that the capacitance value between the two nodes in the RF amplifier circuit reaches the target capacitance value, thereby improving the power-added efficiency and linearity of the RF amplifier circuit.

[0056] In one embodiment, such as Figure 6 As shown, the bias circuit 2 includes a bias transistor M2 and a bias resistor R1; The first end of the bias resistor R1 is connected to the bias transistor M2, and the second end of the bias resistor R1 is coupled to the input terminal of the amplifying transistor M1. A second node P2 is provided between the bias transistor M2 and the first terminal of the bias resistor R1.

[0057] As an example, the bias circuit 2 includes a bias transistor M2 and a bias resistor R1. The first end of the bias resistor R1 is connected to the bias transistor M2, and the second end of the bias resistor R1 is coupled to the input terminal of the amplifying transistor M1. A first node P1 is provided between the input terminal of the amplifying transistor M1 and the signal input terminal In, and a second node P2 is provided between the bias transistor M2 and the first end of the bias resistor R1. At this time, at least one component X1, including the bias resistor R1, is provided on the first node P1 and the second node P2 of the RF amplifier circuit.

[0058] In this example, a third capacitor C3 and a capacitor switching circuit 1 are provided between the first node P1 and the second node P2 of the RF amplifier circuit. When the capacitance value of the third capacitor C3 is determined to meet the power-added efficiency and linearity requirements based on the operating frequency band of the RF amplifier circuit, all switching switches K11 in the capacitor switching circuit 1 can be controlled to be in the on state. At this time, all capacitors in the capacitor switching circuit 1 are not connected between the two nodes, and the first node P1 is grounded through the first capacitor C11, and the second node P2 is grounded through the second capacitor C12. When the capacitance value of the third capacitor C3 is determined to not meet the power-added efficiency and linearity requirements based on the operating frequency band of the RF amplifier circuit, at least one switching switch K11 in the capacitor switching circuit 1 can be controlled to be in the off state. At this time, at least two capacitors in the capacitor switching unit 11 are connected between the two nodes. The two capacitors in the capacitor switching unit 11 are used to increase the linear compensation of the bias circuit 2 to improve the power-added efficiency and linearity of the power amplifier.

[0059] In one embodiment, the radio frequency amplifier circuit further includes a DC blocking capacitor C4, with a first end of the DC blocking capacitor C4 coupled to the signal input terminal In and a second end of the DC blocking capacitor C4 coupled to the input terminal of the amplifier transistor M1; The second terminal of the bias resistor R1 is coupled to the second terminal of the DC blocking capacitor C4; A first node P1 is provided between the signal input terminal In and the first terminal of the DC blocking capacitor C4.

[0060] As an example, the RF amplifier circuit also includes a DC blocking capacitor C4, which can block DC and pass AC signals. The first end of the DC blocking capacitor C4 is coupled to the signal input terminal In, and the second end of the DC blocking capacitor C4 is coupled to the input terminal of the amplifier transistor M1. At this time, a first node P1 is provided between the signal input terminal In and the first end of the DC blocking capacitor C4. Correspondingly, the first end of the bias resistor R1 is connected to the bias transistor M2, and the second end of the bias resistor R1 is coupled to the second end of the DC blocking capacitor C4. That is, the second end of the bias resistor R1 is coupled to the connection node between the second end of the DC blocking capacitor C4 and the input terminal of the amplifier transistor M1. A second node P2 is provided between the bias transistor M2 and the first end of the bias resistor R1. At this time, at least one component X1, including the bias resistor R1 and the DC blocking capacitor C4, is provided between the first node P1 and the second node P2 of the RF amplifier circuit.

[0061] In this example, a third capacitor C3 and a capacitor switching circuit 1 are provided between the first node P1 and the second node P2 of the RF amplifier circuit. When the capacitance value of the third capacitor C3 is determined to meet the power-added efficiency and linearity requirements based on the operating frequency band of the RF amplifier circuit, all switching switches K11 in the capacitor switching circuit 1 can be controlled to be in the on state. At this time, all capacitors in the capacitor switching circuit 1 are not connected between the two nodes, and the first node P1 is grounded through the first capacitor C11, and the second node P2 is grounded through the second capacitor C12. At this time, the first capacitor C11 and the second capacitor C12 can play a decoupling role. When the capacitance value of the third capacitor C3 is determined to not meet the power-added efficiency and linearity requirements based on the operating frequency band of the RF amplifier circuit, at least one switching switch K11 in the capacitor switching circuit 1 can be controlled to be in the off state. At this time, two capacitors in at least one capacitor switching unit 11 are connected between the two nodes. The two capacitors in the capacitor switching unit 11 are used to increase the linear compensation of the bias circuit 2 to improve the power-added efficiency and linearity of the power amplifier.

[0062] In one embodiment, the bias transistor M2 is a bias MOS transistor, the gate of the bias MOS transistor is connected to the bias power supply terminal, the drain of the bias MOS transistor is connected to the power supply terminal VBatt, and the source of the bias MOS transistor is connected to the bias resistor R1. Alternatively, the bias transistor M2 is a bias BJT, with its base connected to the bias power supply terminal, its collector connected to the power supply terminal VBatt, and its emitter connected to the bias resistor R1.

[0063] As an example, the bias transistor M2 can be a bias MOSFET. The gate of the bias MOSFET is connected to the bias power supply terminal and can receive the bias signal received by the bias power supply terminal. The drain of the bias MOSFET is connected to the power supply terminal VBatt, and the source of the bias MOSFET is connected to the first terminal of the bias resistor R1. In this example, the gate voltage determined by the bias signal received by the gate of the bias MOSFET can be used to evaluate whether the drain and source of the bias MOSFET are conducting, thereby controlling the bias MOSFET to turn on or off. When the drain and source of the bias MOSFET are conducting, the bias MOSFET provides bias current to the amplifying transistor M1 through the bias resistor R1. At this time, a third capacitor C3 and a capacitor switching circuit 1 are provided between the signal input terminal In of the RF amplifier circuit and the source of the bias MOSFET. The third capacitor C3 is used to adjust the power-added efficiency and linearity of the RF amplifier circuit. Based on the operating frequency band of the RF amplifier circuit, it is determined whether the two capacitors in the capacitor switching circuit 1 need to be used to increase the linear compensation of the bias circuit 2 to ensure the power-added efficiency and linearity of the RF amplifier circuit.

[0064] As another example, the bias transistor M2 can be a bias BJT. The base of the bias BJT is connected to the bias power supply terminal and can receive the bias signal received from the bias power supply terminal. The drain of the bias BJT is connected to the power supply terminal VBatt, the collector of the bias BJT is connected to the power supply terminal VBatt, and the emitter of the bias BJT is connected to the first terminal of the bias resistor R1. In this example, the base voltage of the bias BJT can be determined based on the bias signal received at its base, and the conduction status of the collector and emitter of the bias BJT can be evaluated to achieve the effect of controlling the bias BJT to turn on or off. When the collector and emitter of the bias BJT are conducting, the bias BJT provides bias current to the amplifying transistor M1 through the bias resistor R1. At this time, a third capacitor C3 and a capacitor switching circuit 1 are provided between the signal input terminal In of the RF amplifier circuit and the emitter of the bias BJT. The third capacitor C3 is used to adjust the power-added efficiency and linearity of the RF amplifier circuit. Based on the operating frequency band of the RF amplifier circuit, it is determined whether the two capacitors in the capacitor switching circuit 1 need to be used to increase the linear compensation of the bias circuit 2 to ensure the power-added efficiency and linearity of the RF amplifier circuit.

[0065] This invention provides an RF front-end module, including the capacitor switching circuit described above, or including the RF amplifier circuit described above.

[0066] A capacitor switching circuit is provided in the RF front-end module. A first capacitor and a second capacitor are connected in series between the first and second connection terminals. A switching switch is used, with one end coupled between the first and second capacitors and the other end grounded. When the switching switch is open, the two capacitors in the capacitor switching unit are connected between the two connection terminals. When the switching switch is on, each connection terminal is grounded through a capacitor. The capacitance value between the two connection terminals is adjusted by using the capacitance value connected to the capacitor switching circuit. This enables effective switching of the capacitance value presented by the capacitor switching circuit, thereby ensuring the overall performance of the circuit.

[0067] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A radio frequency amplifier circuit, characterized in that, The radio frequency amplifier circuit is provided with a first node and a second node, and at least one component is provided between the first node and the second node; The radio frequency amplifier circuit further includes a capacitor switching circuit. The first connection terminal of the capacitor switching circuit is coupled to the first node, and the second connection terminal of the capacitor switching circuit is coupled to the second node. The capacitor switching circuit includes at least one capacitor switching circuit. Each capacitor switching unit includes a first capacitor, a second capacitor, and a switching switch. The first terminal of the first capacitor is connected to the first connection terminal, the second terminal of the first capacitor is connected to the first terminal of the second capacitor, and the second terminal of the second capacitor is connected to the second connection terminal. The first terminal of the switching switch is connected to the second terminal of the first capacitor, and the second terminal of the switching switch is grounded. The radio frequency (RF) amplifier circuit includes an amplifying transistor and a bias circuit; the input terminal of the amplifying transistor is coupled to a signal input terminal, and a first node is provided between the input terminal of the amplifying transistor and the signal input terminal; one end of the bias circuit is coupled to the input terminal of the amplifying transistor, and a second node is provided on the bias circuit; the RF amplifier circuit further includes a third capacitor disposed between the first node and the second node; wherein: When the capacitor switching circuit includes a capacitor switching unit, the capacitor switching circuit is configured such that, when the operating frequency band of the RF amplifier circuit is a first frequency band, the switching state of the switching switch is in the ON state; when the operating frequency band of the RF amplifier circuit is a second frequency band, the switching state of the switching switch is in the OFF state; the first frequency band is less than the second frequency band; or... The capacitor switching circuit includes two capacitor switching units. When the operating frequency band of the RF amplifier circuit is less than a first threshold, both switching units are in the ON state. When the operating frequency band of the RF amplifier circuit is less than a second threshold but not less than the first threshold, one of the two switching units is in the OFF state and the other is in the ON state. When the operating frequency band of the RF amplifier circuit is not less than the second threshold, both switching units are in the OFF state.

2. The radio frequency amplifier circuit as described in claim 1, characterized in that, Both the first connection terminal and the second connection terminal are non-grounded terminals.

3. The radio frequency amplifier circuit as described in claim 1, characterized in that, The switching switch is a first MOSFET. The gate of the first MOSFET is connected to the control power supply terminal, the drain of the first MOSFET is connected to the second terminal of the first capacitor, and the source of the first MOSFET is grounded.

4. The radio frequency amplifier circuit as described in claim 1, characterized in that, The capacitor switching circuit is configured to control the switching state of at least one of the switching switches according to the operating frequency band of the radio frequency amplifier circuit.

5. The radio frequency amplifier circuit as described in claim 1, characterized in that, The capacitor switching circuit is configured to determine the number of switching switches in the off state in the capacitor switching circuit according to the operating frequency band of the radio frequency amplifier circuit.

6. The radio frequency amplifier circuit as described in claim 1, characterized in that, The bias circuit includes a bias transistor and a bias resistor; The first end of the bias resistor is connected to the bias transistor, and the second end of the bias resistor is coupled to the input terminal of the amplifying transistor. The second node is provided between the bias transistor and the first terminal of the bias resistor.

7. The radio frequency amplifier circuit as described in claim 6, characterized in that, The radio frequency amplifier circuit also includes a DC blocking capacitor, with a first end of the DC blocking capacitor coupled to the signal input terminal and a second end of the DC blocking capacitor coupled to the input terminal of the amplifying transistor; The second end of the bias resistor is coupled to the second end of the DC blocking capacitor; The first node is provided between the signal input terminal and the first terminal of the DC blocking capacitor.

8. The radio frequency amplifier circuit as described in claim 6, characterized in that, The bias transistor is a bias MOS transistor, the gate of the bias MOS transistor is connected to the bias power supply terminal, the drain of the bias MOS transistor is connected to the power supply terminal, and the source of the bias MOS transistor is connected to the bias resistor. Alternatively, the bias transistor is a bias BJT, with its base connected to the bias power supply terminal, its collector connected to the power supply terminal, and its emitter connected to the bias resistor.

9. A radio frequency front-end module, comprising the radio frequency amplifier circuit as described in any one of claims 1-8.

Images