Radio-frequency circuit and terminal device

Abstract

Provided in the embodiments of the present application are a radio-frequency circuit and a terminal device. The radio-frequency circuit comprises: a first circuit board and a second circuit board, wherein the first circuit board is connected to the second circuit board, the second circuit board is connected to an antenna module, and the first circuit board at least comprises a radio-frequency chip. The second circuit board comprises: a first switch circuit and a first gain unit, wherein the first switch circuit is used for realizing the transmission of a first radio-frequency signal on the second circuit board via the first gain unit, and the first gain unit is used for performing gain processing on the first radio-frequency signal; the first radio-frequency signal is a radio-frequency signal received by the antenna module; and the radio-frequency chip is used for receiving the first radio-frequency signal which has been subjected to the gain processing. By means of deploying a first gain unit on a second circuit board, which is arranged close to an antenna module, the solution can solve the problem of the overall wireless performance being degraded when a line loss of a long cable or an FPC is too large to be ignored due to a relatively long distance between an antenna and a PCB mainboard in a terminal device.

Description

A radio frequency circuit and a terminal device

[0001] This application claims priority to Chinese Patent Application No. 202510087096.8, filed on January 17, 2025, entitled "A Radio Frequency Circuit and Terminal Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of terminal technology, and in particular to radio frequency circuits and terminal devices. Background Technology

[0003] In mobile phones, tablets, and other terminal devices, the antenna and printed circuit board (PCB) are typically located close together, and can be directly connected to the antenna via metal springs, short cables, or flexible printed circuit boards (FPCs). However, when the distance between the antenna and the PCB is too great, and the line loss of long cables or FPCs becomes too significant to be ignored, substantial line loss can lead to a decrease in the overall wireless performance of the device. Summary of the Invention

[0004] This application provides a radio frequency circuit and a terminal device to solve the problem of degraded overall wireless performance when the antenna is far from the PCB motherboard inside the terminal device and the loss of long cable or FPC line is too great to be ignored.

[0005] In a first aspect, embodiments of this application provide a radio frequency (RF) circuit, including a first circuit board and a second circuit board. The first and second circuit boards are connected, and the second circuit board is connected to an antenna module. The first circuit board includes an RF chip. The second circuit board includes a first switching circuit and a first gain unit. The first switching circuit is used to enable a first RF signal to be transmitted on the second circuit board via or without passing through the first gain unit. The first gain unit is used to perform gain processing on the first RF signal. The first RF signal is the RF signal received by the antenna module. The RF chip is used to receive the first RF signal after gain processing or the first RF signal without gain processing.

[0006] For example, the RF chip is used to receive a first RF signal after it has been amplified by a first gain unit and / or a second gain unit deployed on a first circuit board. Alternatively, the first RF signal may not have been amplified by either the first or second gain unit.

[0007] This application provides a radio frequency (RF) circuit with two circuit boards: a first circuit board and a second circuit board. The second circuit board can be positioned close to an antenna module, while the first circuit board can be positioned away from the antenna module. The first circuit board can be connected to the antenna module via the second circuit board. The second circuit board houses a first switching circuit and a first gain unit (e.g., an LNA) for amplifying the received RF signal. The first switching circuit determines whether the received RF signal is amplified by the first gain unit or not. By arranging the first gain unit and the first switching circuit on the second circuit board, this application achieves RF signal gain using the first gain unit. Furthermore, the pre-positioning of the first gain unit (i.e., its proximity to the antenna module) reduces the noise figure (NF) of the receiving link, improving reception sensitivity. Additionally, the proximity of the second circuit board to the antenna module allows for the use of short cable lines or FPC connections, reducing line loss compared to related technologies where long cable lines or FPCs are used due to the greater distance between the antenna module and the PCB. The solution in this application, by pre-positioning the first gain unit, maintains overall transmission performance and improves reception sensitivity. On the other hand, the first gain unit can be bypassed by receiving the first radio frequency signal through the first switching circuit.

[0008] In one possible implementation of this application, the first gain unit includes a first low-noise amplifier (LNA). This allows the first LNA to amplify the first radio frequency signal.

[0009] It is understood that the first switching circuit is used to switch the transmission of the first radio frequency signal on the second circuit board without passing through the first gain unit or through the first gain unit.

[0010] In one possible implementation of this application, the first circuit board further includes a radio frequency (RF) front-end module, and the RF chip includes a transmit port. The transmit port of the RF chip is connected to the first port of the RF front-end module. The second circuit board also has a first transmit channel connecting the RF front-end module and the antenna module. The first transmit channel is used to transmit a second RF signal transmitted by the RF chip. This allows the second RF signal transmitted by the RF chip to be transmitted to the antenna module via the first transmit channel on the second circuit board.

[0011] For example, there is an inter-board connection between the first and second circuit boards, which can be achieved through an FPC and / or a cable line. Specifically, the first transmission channel can be a signal transmission line deployed on the FPC and / or cable line, which is used to connect the RF front-end module and the antenna module. For example, one end of the signal transmission line is connected to the second port of the RF front-end module, and the other end of the signal transmission line is used to connect to the antenna module.

[0012] In one possible implementation of this application, the first switching circuit is further used to enable or disable the first transmitting channel. Specifically, disabling the connection between the second port of the RF front-end module and the antenna module via the first switching circuit will disable the first transmitting channel, or enabling the connection between the second port of the RF front-end module and the antenna module will enable the first transmitting channel. Specifically, the first switching circuit can be deployed on the first transmitting channel, thereby enabling the connection between the second port of the RF front-end module and the antenna module (i.e., the first transmitting channel) to be disabled when the first switching circuit is disabled, and the connection between the second port of the RF front-end module and the antenna module (i.e., the first transmitting channel) to be enabled when the first switching circuit is closed.

[0013] In one possible implementation of this application, the first circuit board further includes a radio frequency (RF) front-end module, with the transmitter port of the RF chip connected to the first port of the RF front-end module. The second port of the RF front-end module is connected to the antenna module. In this way, the second RF signal transmitted by the RF chip can be directly transmitted to the antenna module via the first circuit board and then transmitted by the antenna module. For example, the second port of the RF front-end module can be connected to the antenna module via a signal transmission line (such as a cable).

[0014] In one possible implementation of this application, the receiving port of the RF chip is connected to a first switching circuit. The first switching circuit is specifically used to switch between a first receiving channel and a second receiving channel. The first receiving channel is a channel between the antenna module and the receiving port of the RF chip via a first gain unit. The second receiving channel is a channel between the antenna module and the RF chip that does not pass through the first gain unit. For example, the receiving port of the RF chip is connected to the first switching circuit via an inter-board connection between the first and second circuit boards. Specifically, the inter-board connection between the first and second circuit boards can use a cable and / or an FPC. A signal transmission line is deployed on the FPC as a signal receiving line, or a cable line is used as the signal receiving line. One end of the signal receiving line is connected to the receiving port of the RF chip, and the other end is connected to the first communication port of the first switching circuit. It is understood that the first receiving channel and the second receiving channel are formed by the channel between the antenna module on the second circuit board and the first communication port of the first switching circuit, as well as the aforementioned signal receiving line.

[0015] In one possible implementation of this application, the first switching circuit includes a first sub-switching circuit and a second sub-switching circuit. The second terminal of the first sub-switching circuit is connected to the receiving port of the RF chip. The first terminal of the first sub-switching circuit is connected to the output terminal of the first gain unit, and the third terminal of the first sub-switching circuit is connected to the fourth terminal of the second sub-switching circuit. The input terminal of the first gain unit is connected to the third terminal of the second sub-switching circuit, and the first terminal of the second sub-switching circuit is connected to the RF front-end module. The second terminal of the second sub-switching circuit is connected to the antenna module. The solution of this application embodiment, through the cooperation of the first and second sub-switching circuits, can realize the switching of the first transmitting channel, the second receiving channel, and the first receiving channel.

[0016] In one possible implementation of this application, a first switching circuit is used to receive a first control signal and a second control signal, and a first gain unit is used to receive a third control signal. When the RF circuit is in a receiving state, the first switching circuit is used to switch the channel between the antenna module and the receiving port of the RF chip to a first receiving channel according to the first control signal and the second control signal, and the first gain unit is used to turn on the first gain unit according to the third control signal. When the RF circuit is in a receiving state, the first switching circuit is used to control the channel between the antenna module and the receiving port of the RF chip to switch to a second receiving channel according to the first control signal and the second control signal, and the first gain unit is used to turn off the first gain unit according to the third control signal.

[0017] In one possible implementation of this application, the radio frequency circuit further includes: a logic circuit, wherein a first output terminal of the logic circuit is connected to a second control terminal of the first switching circuit, and a second output terminal of the logic circuit is connected to a first control terminal of the first switching circuit and a control terminal of the first gain unit. The logic circuit is used to output the first control signal and the third control signal to the first switching circuit and the first gain unit respectively through the second output terminal, and to output a second control signal to the first switching circuit through the first output terminal; the first control signal and the second control signal are used to trigger the first switching circuit to switch the channel between the antenna module and the receiving port of the radio frequency chip to the first receiving channel or the second receiving channel. The third control signal triggers the first gain unit to turn on or off. This scheme can realize the control of the first switching circuit using a logic circuit.

[0018] In one possible implementation of this application, a logic circuit is connected to a radio frequency (RF) chip, which is also connected to an RF front-end module. Specifically, the logic circuit converts multiple level signals provided by the RF chip to the RF front-end module into a first control signal, a second control signal, and a third control signal. This scheme enables the logic circuit to perform logical conversion on multiple level signals output by the RF chip to obtain the first control signal, the second control signal, and the third control signal.

[0019] In one possible implementation of this application, the logic circuit can be deployed on either a second circuit board or a first circuit board. Regardless of whether the logic circuit is deployed on the first or second circuit board, the inter-board connection between the first and second circuit boards includes at least one logic signal transmission line. When the logic circuit is deployed on the first circuit board, the logic signal transmission line includes at least two logic signal transmission lines. One end of each logic signal transmission line is connected to one of the two output terminals of the logic circuit, and the other ends are respectively connected to the first control terminal and the second control terminal of the first switching circuit. Specifically, one logic signal transmission line is used to transmit a first control signal or a third control signal, and the other logic signal transmission line is used to transmit a second control signal. When the logic circuit is deployed on the first circuit board, the logic signal transmission line includes at least three logic signal transmission lines, with one end of each of the three logic signal transmission lines connected to the output terminal of the RF chip and the other end connected to the input terminal of the logic circuit.

[0020] In one possible implementation of this application, the logic circuit includes: a first OR gate, a second OR gate, and a first NOT gate. The first and second input terminals of the first OR gate are respectively connected to the first and third control pins of the RF front-end module. The input terminal of the first NOT gate is connected to the second control pin of the RF front-end module. The output terminals of the first OR gate and the first NOT gate are respectively connected to the two input terminals of the second OR gate. The first, second, and third control pins are used to receive level signals. The output terminal of the second OR gate serves as the second output terminal of the logic circuit and is connected to the first control terminal of the first switching circuit and the control terminal of the first gain unit. The output terminal of the first OR gate serves as the first output terminal of the logic circuit and is connected to the second control terminal of the first switching circuit.

[0021] In one possible implementation of this application, the logic circuit includes: a third OR gate, a fourth OR gate, a fifth OR gate, and a second NOT gate. The first and second input terminals of the third OR gate are respectively connected to the first and third control pins of the RF front-end module. The input terminal of the second NOT gate is used to connect to the second control pin of the RF front-end module. The first, second, and third control pins are used to receive level signals. The output terminals of the third OR gate and the second NOT gate are respectively connected to the two input terminals of the fourth OR gate. The output terminal of the fourth OR gate serves as the second output terminal of the logic circuit, connecting to the first control terminal of the first switching circuit and the control terminal of the first gain unit. The first input terminal of the fifth OR gate is connected to the output terminal of the second NOT gate, the second input terminal of the fifth OR gate is connected to the first input terminal of the third OR gate, and the output terminal of the fifth OR gate serves as the first output terminal of the logic circuit, connecting to the second control terminal of the first switching circuit.

[0022] In one possible implementation of this application, the radio frequency chip is also connected to a first switching circuit and a first gain unit. The radio frequency chip is used to output a first control signal and a third control signal to the first control terminal of the first switching circuit and the control terminal of the first gain unit, respectively, and to output a second control signal to the second control terminal of the first switching circuit. The first control signal and the second control signal are used to trigger the first switching circuit to switch the channel between the antenna module and the receiving port of the radio frequency chip to a first receiving channel or a second receiving channel. The third control signal is used to trigger the first gain unit to turn on or off.

[0023] In one possible implementation of this application, the radio frequency (RF) circuit further includes a second switching circuit. The receiving port of the RF chip is connected to the first switching circuit via the second switching circuit. The first switching circuit is used to switch between a first receiving channel and a second receiving channel. The first receiving channel is a channel between the antenna module and the receiving port of the RF chip via a first gain unit, and the second receiving channel is a channel between the antenna module and the RF chip without passing through the first gain unit. When the RF circuit is in receiving mode, the second switching circuit is used to connect the first communication port of the first switching circuit and the receiving port of the RF chip, with the first communication port connected to either the first receiving channel or the second receiving channel. This allows the first RF signal to be transmitted to the RF chip via either the first receiving channel or the second receiving channel during the receiving process, since the second switching circuit connects the first communication port of the first switching circuit and the receiving port of the RF chip.

[0024] The second switching circuit has a first terminal connected to the second port of the RF front-end module deployed on the first circuit board, a second terminal connected to the receiving port of the RF chip, and a third terminal connected to the first communication port of the first switching circuit. The second switching circuit is used to connect the second port of the RF front-end module to the first communication port of the first switching circuit, or to connect the first communication port of the first switching circuit to the receiving port of the RF chip.

[0025] This solution employs a second circuit board, allowing the connection between the first and second circuit boards to receive or transmit radio frequency signals using only a single signal transmission line.

[0026] In one possible implementation of this application, the second switching circuit can be deployed on the first circuit board. The signal transmission line connecting the first and second circuit boards can be implemented using a cable or an FPC. Specifically, one end of the signal transmission line is connected to the third port of the second switching circuit, and the other end is connected to the first communication port of the first switching circuit.

[0027] In one possible implementation of this application, when the radio frequency circuit is in a transmitting state, the second switching circuit connects the second port of the radio frequency front-end module and the first communication port of the first switching circuit. The radio frequency front-end module is deployed on the first circuit board, and the first communication port is connected to the first transmitting channel. Because the second switching circuit connects the second port of the radio frequency front-end module and the first communication port of the first switching circuit, the second radio frequency signal emitted by the radio frequency chip can enter the second circuit board through the first communication port after passing through the radio frequency front-end module, and then be transmitted to the antenna module through the first transmitting channel on the second circuit board.

[0028] In one possible implementation of this application, the second switching circuit is connected to the radio frequency chip; when the radio frequency circuit is in the transmitting state, the radio frequency chip is used to output a fourth control signal to the second switching circuit, the fourth control signal is used to control the second switching circuit to connect the second port of the radio frequency front-end module and the first communication port of the first switching circuit, the first communication port being connected to the first transmitting channel on the first circuit board;

[0029] When the radio frequency circuit is in the receiving state, the radio frequency chip is used to output a fifth control signal to the second switching circuit. The fifth control signal is used to control the second switching circuit to connect the first communication port of the first switching circuit and the receiving port of the radio frequency chip. The first communication port is connected to the first receiving channel or the second receiving channel.

[0030] In one possible implementation of this application, the first circuit board further includes a radio frequency (RF) front-end module, the RF chip having a receiving port, the receiving port of the RF chip being connected to a third port of the RF front-end module; the second port of the RF front-end module being connected to the first switching circuit;

[0031] The first switching circuit is used to switch between the third and fourth receiving channels on the second circuit board. The third receiving channel is the channel between the antenna module and the second port of the RF front-end module via the first gain unit, and the fourth receiving channel is the channel between the antenna module and the second port of the RF front-end module without passing through the first gain unit. This allows the first RF signal to be transmitted on the second circuit board via either the fourth or third receiving channel, and then enters the RF front-end module via its second port. Afterward, the first RF signal is transmitted to the RF chip through the RF front-end module.

[0032] Specifically, the transmit port of the RF chip is connected to the first port of the RF front-end module, and the receive port of the RF chip is connected to the third port of the RF front-end module.

[0033] The RF front-end module is used to switch between the second transmit channel, the fifth receive channel, and the sixth receive channel within the RF front-end module. The second transmit channel amplifies the second RF signal transmitted by the RF chip and connects the transmit port of the RF chip to the second port of the RF front-end module. The fifth receive channel is the channel between the receive port of the RF chip and the second port of the RF front-end module. The fifth receive channel is used to amplify the first RF signal before transmission to the RF chip. The sixth receive channel connects the receive port of the RF chip to the second port of the RF front-end module. The sixth receive channel is used to prevent the first RF signal from undergoing amplification.

[0034] In one possible implementation of this application, the RF front-end module includes: a second power amplifier, a second gain unit, and a third switching circuit; the second gain unit is located on the fifth receiving channel, the second power amplifier is located on the second transmitting channel, the input terminal of the second power amplifier is connected to the transmitting port of the RF chip, the output terminal of the second power amplifier is connected to the first terminal of the third switching circuit, and the second terminal of the third switching circuit is connected to the second circuit board. The third terminal of the third switching circuit is connected to the input terminal of the second gain unit, and the output terminal of the second gain unit is connected to the receiving port of the RF chip; the third switching circuit is used to switch between the second transmitting channel, the fifth receiving channel, and the sixth receiving channel.

[0035] In one possible implementation of this application, the first switching circuit includes a third sub-switching circuit and a fourth sub-switching circuit, wherein the second terminal of the third sub-switching circuit serves as the first communication port of the first switching circuit, the third terminal of the third sub-switching circuit is connected to the third terminal of the fourth sub-switching circuit, the first terminal of the third sub-switching circuit is connected to the output terminal of the first gain unit, the input terminal of the first gain unit is connected to the first terminal of the fourth sub-switching circuit, and the second terminal of the fourth sub-switching circuit serves as the third communication port of the first switching circuit and is connected to the antenna module.

[0036] In one possible implementation of this application, the first switching circuit and the first gain unit are also connected to the radio frequency chip;

[0037] The radio frequency chip is used to output a fifth control signal to the first control terminal of the first switching circuit and a sixth control signal to the control terminal of the first gain unit. The fifth control signal is used to control the first gain unit to turn on or off, and the sixth control signal is used to control the first switching circuit to switch between the second receiving channel and the first receiving channel.

[0038] In one possible implementation of this application, the connection between the second circuit board and the first circuit board includes: the third terminal of the second switching circuit is connected to the first communication port of the first switching circuit via a flexible printed circuit board (FPC) and / or a cable line.

[0039] In one possible implementation of this application, the radio frequency circuit further includes a filter connected in series between the second circuit board and the antenna module.

[0040] Secondly, embodiments of this application provide a terminal device, which includes the radio frequency circuit described in any of the first aspects above. Attached Figure Description

[0041] Figure 1 is a schematic diagram of a radio frequency circuit provided in an embodiment of this application;

[0042] Figure 2 is a schematic diagram of the layout of radio frequency circuit in a terminal device provided in an embodiment of this application;

[0043] Figure 3 is a schematic diagram of a radio frequency circuit provided in an embodiment of this application;

[0044] Figure 4 is a schematic diagram of a first structure of a radio frequency circuit provided in an embodiment of this application;

[0045] Figure 5 is a schematic diagram of a first structure of a radio frequency circuit provided in an embodiment of this application;

[0046] Figure 6 is a schematic diagram of a first structure of a logic circuit provided in an embodiment of this application;

[0047] Figure 7 is a schematic diagram of a first structure of a radio frequency circuit provided in an embodiment of this application;

[0048] Figure 8 is a schematic diagram of the inter-board connection of a first structure of a radio frequency circuit provided in an embodiment of this application;

[0049] Figure 9 is a schematic diagram of a second structure of a radio frequency circuit provided in an embodiment of this application;

[0050] Figure 10 is a schematic diagram of the circuit structure of a second structure of a radio frequency circuit provided in an embodiment of this application in different scenarios;

[0051] Figure 11 is a comparative schematic diagram of the first structure of the radio frequency circuit provided in the embodiment of this application and the radio frequency circuit in the related art;

[0052] Figure 12 is a schematic diagram of a third structure of a radio frequency circuit provided in an embodiment of this application;

[0053] Figure 13 is a schematic diagram of a third structure of a radio frequency circuit provided in an embodiment of this application;

[0054] Figure 14 is a schematic diagram of a third structure of a radio frequency circuit provided in an embodiment of this application.

[0055] Figures 15 to 19 are schematic diagrams of the structure of a radio frequency circuit under different states provided in the embodiments of this application. Detailed Implementation

[0056] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B; "and / or" in this text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0057] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this embodiment, unless otherwise stated, "a plurality of" means two or more.

[0058] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0059] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0060] It should be understood that in this application, "at least one (item)" means one or more. "More than one" means two or more. "At least two (items)" means two or three or more. "And / or" is used to describe the relationship between related objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural.

[0061] The character " / " generally indicates that the preceding and following objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any single or multiple items. For example, "at least one of a, b, or c" can be expressed as: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0062] Both "...when" and "if" indicate that a corresponding action will be taken under certain objective circumstances. They are not time limits, nor do they require a judgment action to be taken when the action is taken, nor do they imply any other limitations.

[0063] As shown in Figure 1, the current terminal device deploys an antenna module 101 (e.g., antenna module 101 (including antenna 1011 and antenna 1012)) and a circuit board 102, on which radio frequency (RF) circuitry is deployed. The RF circuitry includes an RF chip (also known as a radio frequency integrated circuit) 1021 and a power amplifier (PA) 1022 / low noise amplifier (LNA) 1023.

[0064] As shown in Figure 1(a), the circuit board 102 is positioned close to the antenna module 101. The circuit board 102 and the antenna module 101 can be connected via a short cable, a metal spring, or a flexible printed circuit (FPC). As shown in Figure 1(b), the circuit board 102 can be connected to one antenna 1011 via a cable, a metal spring, or an FPC. The circuit board 102 can also be connected to another antenna 1012 via a small PCB board. Specifically, for example, the circuit board 102 is connected to the small PCB board via a cable, and then the small PCB board is connected to another antenna 1012 via a cable, a metal spring, or an FPC.

[0065] In this application embodiment, circuit board 102 may refer to PCB.

[0066] As shown in Figure 2, the terminal device includes a battery and an antenna module in addition to the radio frequency (RF) circuitry. If the RF circuitry is deployed far from the antenna module within the terminal device—for example, the RF circuitry is deployed on one side of the terminal device while the antenna module is deployed on the other—the RF circuitry and antenna module need to be connected via a long cable or FPC. When the terminal device is large, such as a tablet or computer, the distance between the RF circuitry and the antenna module is greater, thus requiring a longer cable. This increased cable or FPC length leads to increased line loss. Since overall device performance equals circuit conduction performance minus connection loss plus antenna efficiency, even with constant circuit conduction performance and antenna efficiency, excessive line loss from the cable or FPC can degrade the overall wireless performance.

[0067] Based on this, this application provides a radio frequency (RF) circuit with two circuit boards: a first circuit board and a second circuit board. The second circuit board can be positioned close to the antenna module, while the first circuit board can be positioned away from the antenna module. The first circuit board can be connected to the antenna module via the second circuit board. Since the second circuit board houses a first switching circuit and a first gain unit (e.g., an LNA) for amplifying the received RF signal, the first switching circuit determines whether the received RF signal is amplified by the first gain unit or not. This application, by arranging the first gain unit and the first switching circuit on the second circuit board, achieves RF signal gain using the first gain unit. Furthermore, the pre-positioning of the first gain unit (i.e., its proximity to the antenna module) reduces the noise figure (NF) of the receiving link, improving reception sensitivity. Additionally, the proximity of the second circuit board to the antenna module allows for the use of short cable lines or FPC connections, reducing line loss compared to related technologies where long cable lines or FPCs are used due to the greater distance between the antenna module and the PCB. The solution in this application, by pre-positioning the first gain unit, maintains overall transmission performance and improves reception sensitivity. On the other hand, the first gain unit can be bypassed by receiving the first radio frequency signal through the first switching circuit.

[0068] The radio frequency circuits provided in this application embodiment can be applied in terminal devices.

[0069] The terminal device in this application embodiment can be a smartphone, tablet computer, laptop computer, customer premises equipment (CPE), router, smart bracelet, smartwatch, smart helmet, smart glasses, etc. The terminal device can also be a cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, in-vehicle device, electronic device in a 5G network, or terminal device in a future evolved public land mobile network (PLMN), etc., and this application embodiment is not limited to these categories.

[0070] The technical solutions provided in this application are applicable to terminal devices that employ one or more of the following communication technologies: Bluetooth (BT) communication technology, Global Positioning System (GPS) communication technology, Wireless Fidelity (WiFi) communication technology, Long Term Evolution (LTE) communication technology, 5G communication technology, and other future communication technologies.

[0071] As shown in Figure 3, which is a schematic diagram of a radio frequency (RF) circuit according to an embodiment of this application, the RF circuit includes a first circuit board 200 and a second circuit board 300. The first circuit board 200 is connected to the antenna module 400 via the second circuit board 300. That is, the first circuit board 200 is connected to the second circuit board 300, and the second circuit board 300 is connected to the antenna module 400.

[0072] For example, the first circuit board 200 may include a radio frequency (RF) front-end circuit (also known as an RF front-end module). The RF front-end circuit may include an RF chip 201 and a radio frequency front-end module (FEM) 202.

[0073] As shown in Figure 3, the second circuit board 300 includes a first switching circuit 301 and a first gain unit 302. The first switching circuit 301 is used to enable the first radio frequency (RF) signal to be transmitted on the second circuit board 300 via the first gain unit 302 or without passing through the first gain unit 302. The first gain unit 302 is used to perform gain processing on the first RF signal. The first RF signal is the RF signal received by the antenna module 400. The RF chip 201 is used to receive the first RF signal after being amplified by the first gain unit 302 or the first RF signal without being amplified by the first gain unit 302.

[0074] The first radio frequency signal not being transmitted through the first gain unit 302 can also be understood as the first radio frequency signal bypassing the first gain unit 302 during transmission.

[0075] In this embodiment of the application, the first switching circuit 301 can bypass the first gain unit 302 to enable the first radio frequency signal to be transmitted without passing through the first gain unit 302.

[0076] For example, in this embodiment of the application, bypassing the first gain unit 302 can be understood as disconnecting the connection between the first gain unit 302 and the receiving port 2012, and / or disconnecting the connection between the first gain unit 302 and the antenna module 400, so that the first radio frequency signal is not transmitted through the first gain unit 302.

[0077] Specifically, the antenna module 400 receives a first radio frequency (RF) signal. If the first RF signal is transmitted through the first gain unit 302, it can be amplified by the first gain unit 302 before being transmitted to the RF chip 201. This allows for amplification of the received RF signal when the RF circuit is in a receiving scenario. If the first RF signal is not transmitted through the first gain unit 302, it will bypass the first gain unit 302 before being transmitted to the RF chip 201. In the scenario where the first RF signal is not transmitted through the first gain unit 302, the first RF signal received by the antenna module 400 will not undergo amplification processing by the first gain unit 302. This allows the first RF signal to be transmitted to the RF chip 201 without amplification by bypassing the first gain unit 302 when the RF circuit is in a receiving scenario.

[0078] This application provides a radio frequency (RF) circuit with two circuit boards: a first circuit board and a second circuit board. The second circuit board can be positioned close to an antenna module, while the first circuit board can be positioned away from the antenna module. The first circuit board can be connected to the antenna module via the second circuit board. The second circuit board houses a first switching circuit and a first gain unit (e.g., an LNA) for amplifying the received RF signal. The first switching circuit determines whether the received RF signal is amplified by the first gain unit or not. By arranging the first gain unit and the first switching circuit on the second circuit board, this application can achieve RF signal gain using the first gain unit. Furthermore, the pre-positioning of the first gain unit (i.e., its proximity to the antenna module) reduces the NF (noise, ductility, and power) of the receiving link, improving reception sensitivity. Additionally, the proximity of the second circuit board to the antenna module allows for the use of short cable lines or FPCs for connection. Compared to related technologies where long cable lines or FPCs are used due to the greater distance between the antenna module and the PCB, this reduces line loss. The solution in this application, by pre-positioning the first gain unit, maintains overall transmission performance and improves reception sensitivity. On the other hand, the first gain unit can be bypassed by receiving the first radio frequency signal through the first switching circuit.

[0079] In one embodiment of this application, the two circuit boards can each be a PCB. For example, the first circuit board 200 can be a first PCB, and the second circuit board 300 can be a second PCB. As an example, the first circuit board 200 can be referred to as the main circuit board, and the second circuit board 300 can be referred to as the secondary circuit board. The main circuit board typically integrates a processor, RF chip, RF front-end module, memory, flash memory, camera, various sensors, and card slots, etc. The secondary circuit board can also house other devices besides the first switch circuit 301 and the first gain unit 302; this embodiment of the application does not limit this. In one possible embodiment of this application, the second circuit board can be positioned close to the antenna module 400.

[0080] In one embodiment of this application, the radio frequency chip 201 can be used to modulate and demodulate radio frequency signals, and can upconvert (increase the frequency of the radio frequency signal) and downconvert (decrease the frequency of the radio frequency signal) the radio frequency signal.

[0081] In one embodiment, during the transmission of the second radio frequency signal, the radio frequency chip 201 can be used to modulate the frequency of the second radio frequency signal, up-converting it to increase the frequency of the first radio frequency signal to the frequency required for communication. During the reception of the first radio frequency signal, the radio frequency chip 201 can be used to demodulate the frequency of the first radio frequency signal, down-converting it to reduce the frequency of the first radio frequency signal to the frequency required for the remaining processing by the radio frequency chip 201.

[0082] In one possible embodiment of this application, if the RF chip 201 determines that the power of the received first RF signal is too high, it can trigger the first switching circuit 301, causing the first switching circuit 301 to conduct the first RF signal to a channel that does not need to pass through the first gain unit 302. Conversely, if the RF chip 201 determines that the power of the received first RF signal is too low, it can trigger the first switching circuit 301, causing the first switching circuit 301 to conduct the first RF signal to a channel that needs to pass through the first gain unit 302. For example, the RF circuit can default to a receiving channel that passes through the first gain unit 302; if it determines that the power of the received first RF signal is relatively high, it can switch the receiving channel to a channel that does not pass through the first gain unit 302.

[0083] As an example, the radio frequency chip 201 in this application embodiment may be a Wi-Fi chip.

[0084] As an example, antenna module 400 may include one or more antennas, and this application embodiment does not limit this. For example, antenna module 400 may include at least one transmitting antenna and at least one receiving antenna. The transmitting antenna is used to transmit radio frequency signals, and the receiving antenna is used to receive radio frequency signals. Alternatively, antenna module 400 may include at least one antenna, which can be used for both transmitting and receiving radio frequency signals, and this application embodiment does not limit this.

[0085] In one possible embodiment of this application, the first circuit board 200 may be disposed away from the antenna module 400, while the second circuit board 300 may be disposed close to the antenna module 400. The second circuit board 300 may be connected to the antenna module 400 via the first switching circuit 301. There is an inter-board connection between the first circuit board 200 and the second circuit board 300. For example, the first circuit board 200 and the second circuit board 300 may be connected via an FPC, a cable, or both.

[0086] In one possible embodiment of this application, the first gain unit may include a first LNA3021.

[0087] In one embodiment of this application, the first switching circuit 301 may include a switching device connected in series between the first gain unit 302 and the antenna module 400 and / or a switching device connected in series between the first gain unit 302 and the receiving port 2012. Bypassing the first gain unit 302 can be understood as disconnecting at least one of the aforementioned two switching devices. Alternatively, if the input terminal of the first gain unit 302 is connected to the antenna module 400, and the output terminal of the first gain unit 302 is connected to the receiving port via a signal transmission line, then the first switching circuit 301 may include a switching device connected in parallel with the first gain unit 302. In this case, when the first switching circuit 301 is closed, the first gain unit 302 is bypassed, and the first radio frequency signal bypasses the first gain unit 302 and is transmitted to the receiving port 2012 of the radio frequency chip 201. When the first switching circuit 301 is open, the first gain unit 302 is not bypassed, and the first radio frequency signal is transmitted to the receiving port 2012 of the radio frequency chip 201 via the first gain unit 302.

[0088] Alternatively, in one embodiment of this application, if the first switching circuit includes a first sub-switching circuit 3011 connected in series between the first gain unit 302 and the antenna module 400, and a second sub-switching circuit 3012 connected in series between the first gain unit 302 and the receiving port 2012, then bypassing the first gain unit 302 can be understood as: disconnecting the connection between the second terminal of either the first sub-switching circuit 3011 or the second sub-switching circuit 3012 and the target terminal. The target terminal is the port in either the first sub-switching circuit 3011 or the second sub-switching circuit 3012 that is connected to the first gain unit 302.

[0089] As shown in Figure 3, the radio frequency chip 201 provided in this embodiment of the application has a transmit port 2011 and a receive port 2012. It can be understood that the radio frequency chip 201 is used to receive radio frequency signals from the antenna module 400 through the receive port 2012, and to transmit radio frequency signals through the transmit port 2011.

[0090] In this embodiment, the receiver port 2012 of the RF chip 201 can be connected to the second circuit board 300 or the RF front-end module 202, which will be described separately below:

[0091] Case 1) The receiving port 2012 of the RF chip 201 is connected to the first switching circuit 301.

[0092] In this scenario, the channel through which the first radio frequency signal is transmitted via the first gain unit 302 can be referred to as the first receiving channel, and the channel through which the first radio frequency signal is transmitted without passing through the first gain unit 302 can be referred to as the second receiving channel. In other words, the second circuit board 300 includes both the first receiving channel and the second receiving channel. The first switching circuit 301 can then switch between the second receiving channel and the first receiving channel to allow the first radio frequency signal to either pass through or not pass through the first gain unit 302.

[0093] In one embodiment of this application, the first receiving channel is the channel between the antenna module 400 and the RF chip 201 via the first gain unit 302. That is, the first gain unit 302 is located on the first receiving channel and is used to amplify the first RF signal received from the antenna module 400 through the first receiving channel. The second receiving channel is the channel between the antenna module 400 and the RF chip 201 (specifically, between the antenna module 400 and the RF chip 201's receiving port 2012) that does not pass through or bypasses the first gain unit 302. In other words, the first switching circuit 301 is used to connect the first receiving channel between the antenna module 400 and the receiving port 2012, or to bypass the first gain unit 302 to connect the second receiving channel between the antenna module 400 and the receiving port 2012. This allows the RF chip 201 to receive the first RF signal using either the second receiving channel or the first receiving channel.

[0094] It is understandable that when the first switching circuit 301 bypasses the first gain unit 302, it can be assumed that the first switching circuit 301 switches the receiving channel to the second receiving channel (i.e., the first receiving channel is closed and the second receiving channel is open). In this way, the first radio frequency signal from the antenna module 400 will be transmitted to the radio frequency chip 201 without passing through the first gain unit 302.

[0095] When the first switching circuit 301 does not bypass the first gain unit 302, it can be assumed that the first switching circuit 301 switches the receiving channel to the first receiving channel (i.e., the first receiving conduction is turned on and the second receiving conduction is turned off). At this time, the first radio frequency signal from the antenna module 400 is amplified by the first gain unit 302 and then transmitted to the radio frequency chip 201 through the first receiving channel.

[0096] In one possible embodiment of this application, the radio frequency front-end module 202 has a first port 2021 and a second port 2022. The transmit port 2011 of the radio frequency chip 201 is connected to the first port 2021 of the radio frequency front-end module 202. The radio frequency front-end module 202 is at least used to amplify the second radio frequency signal received through the first port 2021, and to transmit the amplified second radio frequency signal through the second port 2022 of the radio frequency front-end module 202.

[0097] In one possible implementation of this application, the second port 2022 is connected to the antenna module 400, so that the amplified second radio frequency signal can be transmitted to the antenna module 400 through the second port 2022 and radiated out through the antenna module 400.

[0098] In another possible implementation of this application, the second port 2022 can be connected to the antenna module 400 via a switching device, which is used to conduct the transmission channel between the second port 2022 and the antenna module 400. Specifically, the switching device can be the first switching circuit 301, or it can be other switching circuits besides the first switching circuit 301. This application embodiment does not limit this.

[0099] In one possible embodiment of this application, as shown in Figures 3(a) and (b), the radio frequency circuit can also be used to transmit a second radio frequency signal, which can be transmitted to the antenna module 400 via the first transmission channel. The difference between Figures 3(a) and (b) is that in Figure 3(a), the second port 2022 of the radio frequency front-end module 202 can be connected to the antenna module 400 to form the first transmission channel, while in Figure 3(b), the second port 2022 of the radio frequency front-end module 202 is connected to the antenna module 400 via the second circuit board 300 to form the first transmission channel.

[0100] As an example, the first switching circuit 301 is also connected to the second port 2022 of the RF front-end module 202. The first switching circuit 301 is also used to disconnect the connection between the second port 2022 of the RF front-end module 202 and the antenna module 400, thereby disconnecting the first transmission path between the second port 2022 of the RF front-end module 202 and the antenna module 400. Alternatively, the first switching circuit 301 is used to connect the connection between the second port 2022 of the RF front-end module 202 and the antenna module 400, thereby connecting the first transmission path between the second port 2022 of the RF front-end module 202 and the antenna module 400.

[0101] With the connection between the second port 2022 of the RF front-end module 202 and the antenna module 400, the second RF signal emitted by the RF chip 201 through the transmit port 2011 can enter the RF front-end module 202 through the first port 2021. After the RF front-end module 202 processes the second RF signal, the processed second RF signal is transmitted to the antenna module 400 through the first transmit channel via the second port 2022, and then radiated out by the antenna module 400.

[0102] In one embodiment of this application, when the radio frequency circuit is in the transmitting state, the first switching circuit 301 is used to turn on the first transmission path between the second port 2022 of the radio frequency front-end module 202 and the antenna module 400, so that the second radio frequency signal transmitted by the radio frequency chip 201 through the transmitting port 2011 is transmitted to the antenna module 400 through the first transmission path after passing through the radio frequency front-end module 202.

[0103] In one embodiment of this application, the RF front-end module 202 further has a third port 2026, and there is no connection between the receiving port 2012 of the RF chip and the third port 2026 of the RF front-end module. Alternatively, although the receiving port 2012 of the RF chip is connected to the third port 2026 of the RF front-end module, there is no channel between the antenna module 400 and the third port 2026, so the first RF signal received by the antenna module 400 will not be transmitted to the RF chip 201 through the RF front-end module 202.

[0104] The structure of the radio frequency front-end module 202 provided in the embodiment of this application will be described below with reference to Figure 4.

[0105] As shown in Figure 4, the RF front-end module 202 includes a second power amplifier PA2023 and a third switching circuit 2025. The second power amplifier PA2023 is used to amplify the second RF signal received through the first port 2021.

[0106] Integrating the power amplifier (PA) and switching devices into the RF front-end module can reduce the area occupied by the PA and switching devices, effectively improving the integration of the circuit.

[0107] The second power amplifier PA2023 is connected in series between the transmit port 2011 of the RF chip 201 and the first terminal 20251 of the third switching circuit 205. Specifically, the input terminal of the second power amplifier PA2023 is connected to the first port 2021 of the RF front-end module (the first port 2021 is connected to the transmit port 2011). The output terminal of the second power amplifier PA2023 is connected to the first terminal 20251 of the third switching circuit 2025.

[0108] The second terminal 20252 of the third switching circuit 2025 serves as the second port 2022 of the RF front-end module 202. Alternatively, the second terminal 20252 of the third switching circuit 2025 can be connected to the second port 2022 of the RF front-end module 202.

[0109] In an optional embodiment of this application, the RF front-end module 202 further includes a second gain unit. The second gain unit is used to amplify the received signal. For example, the second gain unit can be a second LNA2024.

[0110] In a scenario where the RF front-end module 202 also includes a second gain unit, the third terminal of the third switching circuit 2025 is connected to the input terminal of the second LNA 2024. The output terminal of the second LNA 2024 is connected to the third port 2026 of the RF front-end module 202, or the output terminal of the second LNA 2024 can be referred to as the third port 2026 of the RF front-end module 202.

[0111] If the second LNA2024 is not included in the RF front-end module 202, the third switching circuit 2025 can also be a single-pole single-throw (SPST) switch. In this case, the second end of the third switching circuit 2025 is one end of the SPST switch, and the other end of the SPST switch is the first end of the third switching circuit 2025 connected to the output of the second power amplifier PA2023.

[0112] When the RF front-end module 202 includes a second LNA 2024, the third switching circuit 2025 can be a single-pole double-throw (SPDT) switch, a single-pole multi-throw switch, a double-pole double-throw switch, or a multi-pole multi-throw switch as shown in Figure 4. This application embodiment does not limit this.

[0113] Understandably, when the third switching circuit 2025 uses a double-pole double-throw switch or a multi-pole multi-throw switch, one of the common ports (i.e., the moving end) can be selected as the second end of the third switching circuit 2025, and then at least two input ports (i.e., the stationary ends) can be selected as the first and third ends of the third switching circuit 2025 respectively.

[0114] In another possible embodiment of this application, the third switching circuit 2025 may also include a switching device 1 connected in series between the output terminal of the second port 2022 and the second PA2023, and a switching device 2 connected in series between the input terminal of the second port 2022 and the second LNA2024.

[0115] For example, when the switching device 1 is turned on, the second transmission channel between the second port 2022 and the output terminal of the second PA2023 in the RF front-end module 202 is turned on.

[0116] For example, when the switching device 1 is turned off, the second transmission channel between the second port 2022 and the output terminal of the second PA2023 in the RF front-end module 202 is turned off.

[0117] For example, when the switching device 2 is turned on, the receiving channel between the second port 2022 in the RF front-end module 202 and the input terminal of the second LNA 2024 is turned on.

[0118] For example, when the switching device 2 is turned off, the receiving channel between the second port 2022 in the RF front-end module 202 and the input terminal of the second LNA 2024 is turned off.

[0119] As shown in Figure 4, taking the RF front-end module 202 as an example, which includes a second LNA 2024 and a third switching circuit 2025 using a single-pole double-throw switch, one input port of the single-pole double-throw switch serves as the first terminal of the third switching circuit 2025. The other input port of the single-pole double-throw switch serves as the third terminal of the third switching circuit 2025. The common port of the single-pole double-throw switch serves as the second terminal of the third switching circuit 2025.

[0120] The second PA2023 can be set on the second transmission channel between the first port 2021 and the second port 2022 to amplify the power of the transmitted second radio frequency signal.

[0121] The second LNA 2024 can be located on the receiving channel within the RF front-end module 202 to amplify the power of the first RF signal received by the antenna module 400. The receiving channel within the RF front-end module 202 refers to the channel between the third port 2026 and the third terminal of the third switching circuit 2025. The third switching circuit 2025 can be used to switch the RF channel (transmit channel or receive channel) connected to the antenna module in different time slots.

[0122] For example, the second LNA2024 and the second PA2023 can be deployed in the same RF front-end module 202 or in different RF front-end modules 202.

[0123] The different electrical connection states of the third switching circuit 2025 shown in Figure 4 (switching the antenna module to the transmit channel or the receive channel) enable the RF front-end circuit to operate in a time division dual (TDD) communication system.

[0124] For example, in the time slot corresponding to the transmitted signal, the third switching circuit 2025 switches to the second transmission channel, so that the second transmission channel is electrically connected to the antenna module 400 through the second circuit board 300. The second radio frequency signal is amplified by the second PA2023 and transmitted to the antenna module 400 through the second transmission channel and the first transmission channel and radiated to the outside.

[0125] In the transmit channel of the RF front-end circuit, the power amplifier (PA) is used to amplify the power of the RF signal to meet communication requirements. Among them, the PA based on the Doherty architecture has advantages such as low power consumption, high efficiency, and good linearity, and is used in RF modules.

[0126] When the RF circuit is in transmit mode, the RF chip 201 transmits a second RF signal through the transmit port 2011, and the first port 2021 of the RF front-end module 202 receives the second RF signal. After passing through the second PA 2023, the second RF signal is amplified by the second PA 2023. The amplified second RF signal is transmitted to the second circuit board 300 through the second port 2022, and then transmitted to the antenna module 400 through the first transmit channel on the second circuit board 300, and radiated outward by the antenna module 400.

[0127] It is understandable that the RF front-end module 202 may not have a second power amplifier PA2023. In this scenario, the third switch circuit 2025 is used to connect the second transmission path between the second port 2022 and the first port 2021 in the transmission state, as shown in Figure 4(a), where the second terminal of the third switch circuit 2025 is connected to the first terminal of the third switch circuit 2025. In the transmission state, the RF chip 201 transmits the second RF signal through the transmit port 2011, and the first port 2021 of the RF front-end module 202 receives the second RF signal. After being transmitted through the second transmission channel, the second RF signal is transmitted to the second circuit board through the second port 2022, and then transmitted to the antenna module 400 through the first transmission channel on the second circuit board 300, and radiated to the outside by the antenna module 400.

[0128] It is understandable that if the second power amplifier PA2023 is in the RF front-end module 202 and the second power amplifier PA2023 is in the off state, then the second RF signal passing through the second power amplifier PA2023 will not be amplified.

[0129] Specifically, when the RF front-end module 202 includes a second power amplifier PA2023, the RF chip 201 can determine whether to turn on the second power amplifier PA2023 based on the power of the transmitted second RF signal. For example, if the power of the second RF signal meets the requirements, the RF chip 201 can control the second power amplifier PA2023 to turn off. If the power of the second RF signal does not meet the requirements, the RF chip 201 can control the second power amplifier PA2023 to turn on.

[0130] In one possible embodiment of this application, the second power amplifier PA2023 can be a high-power amplifier, or it can be composed of multiple power amplifier stages. By increasing the PA's transmission power, the losses in the inter-board connections can be compensated, maintaining the overall transmission performance of the device.

[0131] In one possible embodiment of this application, taking the radio frequency chip 201 as a Wi-Fi chip as an example, for Wi-Fi products, the radio frequency front-end module 202 can be divided into 2.4G FEM and 5G FEM, which are applied to the 2.4G frequency band and 5G frequency band respectively.

[0132] As an example, the structure of the first switching circuit 301 involved in the embodiments of this application will be described below with reference to FIG4.

[0133] As shown in Figure 4, the first switching circuit 301 includes a first sub-switching circuit 3011 and a second sub-switching circuit 3012. The first gain unit 302 may include a first LNA 3021.

[0134] The first sub-switch circuit 3011 and the second sub-switch circuit 3012 can be single-pole multi-throw switches or multi-pole multi-throw switches.

[0135] The first sub-switch circuit 3011 is connected in series between the receiver port 2012 of the RF chip 201 and the output terminal of the first LNA 3021, and is used to turn on or off the channel between the receiver port 2012 and the output terminal of the first LNA 3021. The second sub-switch circuit 3012 is connected in series between the antenna module 400 and the input terminal of the first LNA 3021, and is used to turn on or off the channel between the antenna module 400 and the output terminal of the first LNA 3012. The second sub-switch circuit 3012 is also connected to the second port 2022 of the RF front-end module 202 and the first sub-switch circuit 3011. The second sub-switch circuit 3012 is used to turn on the first transmission channel between the second port 2022 of the RF front-end module 202 and the antenna module 400, and is also used to combine with the first sub-switch circuit 3011 to bypass the first LNA 3021.

[0136] In this circuit, the second terminal 30111 of the first sub-switch circuit 3011 is connected to the receiving port 2012 of the RF chip 201. The first terminal 30112 of the first sub-switch circuit 3011 is connected to the output terminal of the first LNA 3021. The third terminal 30113 of the first sub-switch circuit 3011 is connected to the fourth terminal 30124 of the second sub-switch circuit 3012. The third terminal of the second sub-switch circuit 3012 is connected to the input terminal of the first LNA 3021. The first terminal 30122 of the second sub-switch circuit 3012 is connected to the second port 2022 of the RF front-end module 202. The second terminal 30121 of the second sub-switch circuit 3012 is connected to the antenna module 400.

[0137] For example, in one possible implementation, as shown in the transmission scenario in Figure 4(a), the second terminal 30121 of the second sub-switch circuit 3012 is connected to the first terminal 30122 of the second sub-switch circuit 3012 to establish a first transmission channel between the antenna module 400 and the second port 2022 of the RF front-end module 202. In scenarios other than the transmission scenario, the second terminal 30121 of the second sub-switch circuit 3012 can be disconnected from the first terminal of the second sub-switch circuit 30122.

[0138] In this way, during transmission, the second radio frequency signal or the amplified second radio frequency signal is transmitted to the antenna module 400 through the first transmission channel and radiated to the outside by the antenna module 400.

[0139] In one possible implementation, as shown in Figure 4(b) of the receiving scenario, the second terminal 30121 of the second sub-switch circuit 3012 is connected to the fourth terminal 30124 of the second sub-switch circuit 3012. The second terminal 30111 of the first sub-switch circuit 3011 is connected to the third terminal 30113 of the first sub-switch circuit 3011 to bypass the first LNA 3021. This opens the second receiving channel between the antenna module 400 and the receiving port 2012 of the RF chip 201. It can be understood that when the first LNA 3021 is bypassed, the first receiving channel between the antenna module 400, the first LNA 3021, and the receiving port 2012 of the RF chip 201 will be unusable. Thus, the first RF signal received by the antenna module 400 is transmitted to the receiving port 2012 of the RF chip 201 through the second receiving channel and is received by the RF chip 201.

[0140] It is understandable that when the second terminal 30121 of the second sub-switch circuit 3012 is connected to the fourth terminal 30124 of the second sub-switch circuit 3012, it can be assumed that one end of the second receiving channel is connected to the antenna module 400. When the second terminal 30111 of the first sub-switch circuit 3011 is connected to the third terminal 30113 of the first sub-switch circuit 3011, it can be assumed that the other end of the second receiving channel is connected to the receiving port 2012.

[0141] The circuit shown in Figure 4(b) enables the RF circuit to be bypassed by the first LNA3021 when it is in the receiving state, thereby enabling the RF chip 201 to receive the first RF signal received by the antenna module 400 through the second receiving channel.

[0142] In another possible implementation, as shown in Figure 4(c) of the receiving scenario, the second terminal 30121 of the second sub-switch circuit 3012 is connected to the second terminal 30123 of the second sub-switch circuit 3012. The second terminal 30111 of the first sub-switch circuit 3011 is connected to the first terminal 30112 of the first sub-switch circuit 3011, thereby connecting the channel between the antenna module 400 and the first LNA 3021, and the channel between the output terminal of the first LNA 3021 and the receiving port 2012, thus realizing the conduction of the first receiving channel. Since the first radio frequency signal received by the antenna module 400 is transmitted to the first LNA 3021 for amplification after passing through the second sub-switch circuit 3012, and the amplified first radio frequency signal obtained after passing through the first LNA 3021 is transmitted to the radio frequency chip 201 through the receiving port 2012 via the first receiving channel, the RX gain function can be realized.

[0143] It is understood that, in the embodiments of this application, the first receiving channel includes: the channel between the antenna module 400 and the input terminal of the first gain unit 302, and the channel between the output terminal of the first LNA 3021 and the receiving port 2012.

[0144] When the second terminal 30121 of the second sub-switch circuit 3012 is connected to the second terminal 30123 of the second sub-switch circuit 3012, it can be assumed that one end of the first receiving channel is connected to the antenna module 400. When the second terminal 30121 of the first sub-switch circuit 3011 is connected to the first terminal 30112 of the first sub-switch circuit 3011, it can be assumed that the other end of the first receiving channel is connected to the receiving port 2012.

[0145] In one embodiment of this application, the antenna module 400 is connected to the second circuit board 300 via a filter. The filter can be used to filter out out-of-band spurious signals of the first radio frequency signal input to the radio frequency chip 201, thereby improving the operating efficiency of the radio frequency chip 201. Alternatively, the filter can also be used to filter out out-of-band spurious signals of the transmitted second radio frequency signal.

[0146] For example, as shown in Figure 4, specifically, in this embodiment of the application, a filter 500 is connected in series between the antenna module 400 and the second terminal 30121 of the second sub-switch circuit 3012. For example, the filter 500 can be a bandpass filter, a low-pass filter, or an LC filter composed of an inductor and a capacitor.

[0147] In one embodiment of this application, the filter is integrated within the second circuit board 300, reducing the area occupied by the filter layout and improving the integration of the radio frequency circuit.

[0148] During the signal reception process of the radio frequency circuit, as shown in Figure 4(b), the antenna module 400 receives the radiated electromagnetic wave and converts it into a first radio frequency signal. Then, the antenna module 400 transmits the first radio frequency signal to the filter 500. Since the second receiving channel is turned on, the first radio frequency signal processed by the filter 500 is transmitted to the radio frequency chip 201 through the second receiving channel.

[0149] It is understandable that, with a filter 500 connected in series between the antenna module 400 and the second terminal 30121 of the second sub-switch circuit 3012, the first LNA 3021 is specifically used to amplify the first radio frequency signal after it has been filtered by the filter 500. During the signal reception process of the radio frequency circuit, as shown in Figure 4(c), the antenna module 400 receives the radiated electromagnetic wave and converts it into a first radio frequency signal. Then, the antenna module 400 transmits the first radio frequency signal to the filter 500. Since the first receiving channel is active, the first radio frequency signal processed by the filter 500 is transmitted to the first LNA 3021 for amplification after passing through the first receiving channel. The first radio frequency signal after passing through the first LNA 3021 is then transmitted to the radio frequency chip 201 through the first receiving channel.

[0150] In the above embodiments, the first sub-switch circuit 3011 can be a single-pole double-throw (SPDT) switch, and the second sub-switch circuit 3012 can be a single-pole triple-throw (SPTX) switch. In practical applications, the first sub-switch circuit 3011 can also be a single-pole x-throw (SPXT) switch. Whether it is a single-pole double-throw switch, a single-pole triple-throw switch, a double-pole double-throw switch, or a multi-pole triple-throw switch, these switches include at least one common port (i.e., the moving end) and X input ports (X>2) (i.e., the stationary ends). Two of the X input ports can be used as the first and third ends of the first sub-switch circuit 3011 in the above embodiments. The common port can be used as the second end of the first sub-switch circuit 3011. Alternatively, the first sub-switch circuit 3011 can also be a double-pole double-throw (DPDT), a double-pole x-throw (DPXT), or a multi-pole x-throw (XPXT) switch, which can also be used in the above embodiments.

[0151] Regardless of whether the second sub-switch circuit 3012 adopts a single-pole triple-throw switch, a double-pole triple-throw switch (DPDT), a double-pole multi-throw switch (DPXT), or a multi-pole multi-throw switch (XPXT), these switches include at least one common port and Y input ports (Y>3). Three of the Y input ports can be used as the first, third, and fourth terminals of the second sub-switch circuit 3012. One of the at least one common port can be used as the second terminal of the second sub-switch circuit 3012.

[0152] The following describes how the first switching circuit 301 can be used to bypass the first LNA 3021 to form a first receiving channel or a second receiving channel.

[0153] In one possible implementation of this application, the first switching circuit 301 is used to receive a first control signal and a second control signal. The first gain unit 302 is used to receive a third control signal.

[0154] As one example, the first control signal and the second control signal can be control signals output from the same output terminal, that is, the first control terminal of the first switching circuit 301 and the control terminal of the first gain unit 302 are connected to the same output terminal or output pin. As another example, the first control signal and the second control signal of the first gain unit 302 are control signals output from different control terminals, that is, the first control terminal of the first switching circuit 301 and the control terminal of the first gain unit 302 are connected to different output terminals or output pins.

[0155] As an example, in this embodiment of the application, the first control signal, the second control signal, and the third control signal can all be level signals. For instance, the first control signal and the third control signal can both be first level signals, and the second control signal can be a second level signal. In this case, one of the second level signal and the first level signal is a high-level signal, and the other is a low-level signal.

[0156] When the RF circuit is in transmit mode, the first control signal and the second control signal are used to trigger the first switching circuit 301 to turn on the first transmit channel. Correspondingly, the first switching circuit 301 is used to turn on the first transmit channel according to the first control signal and the second control signal. The first gain unit 302 is used to turn off the first gain unit 302 according to the third control signal. For example, in transmit mode, the first control signal, the third control signal, and the second control signal can be high-level signals.

[0157] Specifically, referring to Figure 4, taking the first switching circuit 301, which includes a first sub-switching circuit 3011 and a second sub-switching circuit 3012, as an example, the first sub-switching circuit 3011 has a first control terminal. The second sub-switching circuit 3012 has a first control terminal and a second control terminal. The first control terminal of the first switching circuit 301 includes: the first control terminal of the first sub-switching circuit 3011 and the first control terminal of the second sub-switching circuit 3012. The second control terminal of the first switching circuit 301 includes: the second control terminal of the second sub-switching circuit 3012. The first control terminal of the first sub-switching circuit 3011 is used to receive a first control signal. The first control terminal of the second sub-switching circuit 3012 is used to receive the first control signal, and the second control terminal of the second sub-switching circuit 3012 is used to receive a second control signal. The control terminal of the first gain unit 302 is used to receive a third control signal.

[0158] For example, after the second sub-switch circuit 3012 receives the first control signal and the second control signal through the first control terminal and the second control terminal respectively, the second sub-switch circuit 3012 connects its second terminal 30121 to its first terminal 30122. The first sub-switch circuit 3011 connects its second terminal to its first terminal 30112 based on the first control signal. The specific circuit structure is shown in Figure 4(a).

[0159] In one possible implementation of this application, when the radio frequency circuit is in a receiving state, a first control signal and a second control signal are used to trigger a first switching circuit 301 to turn on the first receiving channel. The first switching circuit 301 is also used to turn on the first receiving channel according to the first control signal and the second control signal. A first gain unit 302 is used to turn on the first gain unit 302 according to a third control signal. For example, the first control signal and the third control signal can be low-level signals. The second control signal can also be a low-level signal.

[0160] For example, after receiving the first control signal and the second control signal, the second sub-switch circuit 3012 connects its second terminal 30121 to its third terminal 30123. The first sub-switch circuit 3011 connects its second terminal 30111 to its first terminal 30112 based on the first control signal, as shown in Figure 4(c).

[0161] When the RF circuit is in receiving mode, the first control signal and the second control signal trigger the first switching circuit 301 to turn on the second receiving channel. The first switching circuit 301 is used to turn on the second receiving channel according to the first control signal and the second control signal. The first gain unit 302 is used to turn off the first gain unit 302 according to the third control signal. For example, the first control signal and the third control signal can be high-level signals. The second control signal can be a low-level signal.

[0162] For example, as shown in Figure 4(b), after receiving the first control signal and the second control signal, the second sub-switch circuit 3012 connects its second terminal 30121 to its fourth terminal 30124. The first sub-switch circuit 3011 connects its second terminal 30111 to its third terminal 30113 based on the first control signal.

[0163] The following description, in conjunction with Figures 5 and 7, describes the apparatus in this application that provides a first control signal and a second control signal to a first switching circuit 301 and a third control signal to a first gain unit 302.

[0164] It is understandable that, in addition to the logic circuit and the RF chip 201 providing control signals for the first switching circuit 301 and the first gain unit 302, other devices may also provide control signals for the first switching circuit 301 and the first gain unit 302. This application embodiment does not limit this.

[0165] (1) The control signal is provided by the logic circuit.

[0166] In one possible embodiment of this application, as shown in FIG5, the radio frequency circuit provided in this application embodiment may further include: logic circuit 600.

[0167] The logic circuit 600 is connected to the first switching circuit 301 and the first gain unit 302. When the RF circuit is in transmit mode, the logic circuit 600 controls the first switching circuit 301 to turn on the first receiving channel. When the RF circuit is in receive mode, the logic circuit 600 controls the first switching circuit 301 to turn on either the first receiving channel or the second receiving channel. When the RF circuit is in receive mode, the logic circuit 600 also controls the first gain unit 302 to turn on or off via a third control signal; and when the RF circuit is in transmit mode, the logic circuit 600 also controls the first gain unit 302 to turn off via the third control signal.

[0168] As an example, logic circuit 600 has a first output terminal (out1) and a second output terminal (out2), wherein logic circuit 600 is used to output a first control signal and a third control signal to the first switching circuit 301 and the first gain unit 302 respectively through the second output terminal, and to output a second control signal to the first switching circuit 301 through the first output terminal.

[0169] For example, the second output terminal of logic circuit 600 is connected to the first control terminal of the second sub-switch circuit 3012 (e.g., SP4T-VC1), the control terminal of the first gain unit 302 (e.g., LNA Ven), and the first control terminal of the first sub-switch circuit 3011 (e.g., SPDT-Vct1). The second output terminal of logic circuit 600 is used to output the first control signal (i.e., the third control signal). The first output terminal of logic circuit 600 is connected to the second control terminal of the second sub-switch circuit 3012 (e.g., SP4T-VC2) and is used to output the second control signal.

[0170] In one example of this application, when the radio frequency circuit is in the transmitting state, the logic circuit 600 outputs a high-level signal as a first control signal to the first control terminal of the second sub-switch circuit 3012, the control terminal of the first gain unit 302, and the first control terminal of the first sub-switch circuit 3011, and outputs a high-level signal as a second control signal to the second control terminal of the second sub-switch circuit 3012. That is, when the radio frequency circuit is in the transmitting state, both the first control signal and the second control signal can be high-level signals.

[0171] In one example of this application, when the RF circuit is in the receiving state, to achieve the received signal gain function, the logic circuit 600 outputs a low-level signal as a first control signal to the first control terminal of the second sub-switch circuit 3012, the control terminal of the first gain unit 302, and the first control terminal of the first sub-switch circuit 3011, and outputs a low-level signal as a second control signal to the second control terminal of the second sub-switch circuit 3012. That is, when the RF circuit is in the receiving state, both the first and second control signals can be low-level signals to achieve the received signal gain.

[0172] In one example of this application, when the RF circuit is in the receiving state, to achieve the bypass function, the logic circuit 600 outputs a high-level signal as a first control signal to the first control terminal of the second sub-switch circuit 3012, the control terminal of the first gain unit 302, and the first control terminal of the first sub-switch circuit 3011, and outputs a low-level signal as a second control signal to the second control terminal of the second sub-switch circuit 3012. That is, when the RF circuit is in the receiving state, the first control signal can be a high-level signal, and the second control signal can be a low-level signal. Thus, the first control signal controls the first gain unit 302 to turn off, and the first control signal controls the combination of the first sub-switch circuit 3011 and the second sub-switch circuit 3012 to bypass the first gain unit 302.

[0173] In one possible embodiment of this application, the logic circuit 600 may be deployed on the first circuit board 200 or on the second circuit board 300, and this embodiment of the application does not limit this.

[0174] The above scheme describes the first control signal and the second control signal provided by logic circuit 600. The following will describe the structure of logic circuit 600 and how logic circuit 600 provides the first control signal and the second control signal.

[0175] In one possible embodiment of this application, as shown in Figure 6(a), the logic circuit 600 can also be connected to the radio frequency chip 201, which is further connected to the radio frequency front-end module 202. The radio frequency chip 201 is used to output multiple level signals; the multiple level signals are used to control the radio frequency front-end module 202. Specifically, the logic circuit 600 is used to convert the multiple level signals into a first control signal and a second control signal.

[0176] For example, the RF chip 201 has multiple output terminals. In the case of a Wi-Fi chip operating in the 2.4GHz band, the multiple output terminals of the RF chip 201 include GPIO0 to GPIO3. The RF front-end module 202, also operating in the 2.4GHz band, includes ports C0 to C3. For instance, GPIO0 is connected to port C0, GPIO1 to port C1, GPIO2 to port C2, and GPIO3 to port C3. The multiple input terminals of the logic circuit 600 are connected one-to-one with the multiple output terminals of the RF chip 201.

[0177] Specifically, when the Wi-Fi chip operates on the 5G band, the RF chip 201 has multiple outputs including GPIO0 to GPIO2, and the RF front-end module 202, also operating on the 5G band, includes ports C0 to C2. For example, GPIO0 is connected to port C0, GPIO1 to port C1, and GPIO2 to port C2. The logic circuit 600 has multiple inputs that are connected one-to-one with the multiple outputs of the RF chip 201.

[0178] Specifically, the RF chip 201 is used to output level signals to control the RF front-end module 202 through multiple output ports. For example, as shown in Table 1, when the RF circuit is in the transmit state, the RF chip 201 is used to output level signals 1, 2, and 3 through GPIO0 to GPIO2 respectively. Level signals 1, 2, and 3 are used to control the second PA 2023, the third switching circuit 2025, and the second LNA 2024 respectively.

[0179] For example, when the RF circuit is in transmit mode, level signal 1 is used to control the second PA2023 to turn on. When the RF circuit is in transmit mode, level signal 2 is used to control the third switch circuit 2025 to turn on the second transmit channel. When the RF circuit is in transmit mode, level signal 3 is used to control the second LNA2024 to turn off.

[0180] For example, level signal 1 can be a high-level signal to trigger the second PA2023 to turn on. Level signal 2 can be a low-level signal to connect the second terminal 20252 of the third switch circuit 2025 to the first terminal 20251. Level signal 1 can also be a high-level signal to connect the second terminal 20252 of the third switch circuit 2025 to the third terminal 20253. Level signal 3 can be a high-level signal to trigger the second LNA2024 to turn off, or a low-level signal to trigger the second LNA2024 to turn on.

[0181] The logic circuit 600 is specifically used to convert multiple level signals (e.g., level signal 1 to level signal 2) provided by the RF chip 201 to the RF front-end module 202 into a first control signal and a second control signal.

[0182] The specific structure of the logic circuit 600 is not limited in the embodiments of this application. Any circuit structure or control device that can realize the function of outputting the first control signal and the second control signal can be used as the logic circuit in the embodiments of this application.

[0183] The specific structure of the logic circuit 600 involved in the embodiments of this application will be described below with reference to FIG6.

[0184] As shown in Figure 6(a), this is a structure of a logic circuit 600 involved in an embodiment of this application. The logic circuit 600 includes: a first OR gate device 601a, a first NOT gate device 602a and a second OR gate device 603a.

[0185] The first input terminal and the second input terminal of the first OR gate device 601a are respectively connected to the C2 port and the C0 port of the RF front-end module 202. Alternatively, the first input terminal and the second input terminal of the first OR gate device 601a can be considered to be connected to GPIO2 and GPIO0 of the RF chip 201, respectively.

[0186] The input terminal of the first NOT gate device 602a is connected to the C1 port of the RF front-end module 202. Alternatively, it can be considered that the input terminal of the first NOT gate device 602a is connected to GPIO1 of the RF chip 201.

[0187] The outputs of the first NOT gate 602a and the first OR gate 601a are respectively connected to the first and second inputs of the second OR gate 603a. The output of the second OR gate 603a serves as the second output of the logic circuit 600 and is connected to the first control terminal of the second sub-switch circuit 3012 (e.g., SP4T-VC1), the first control terminal of the first sub-switch circuit 3011 (e.g., SPDT-Vct1), and the control terminal of the first LNA 3021 (e.g., LNA Ven). The output of the first OR gate 601a serves as the first output of the logic circuit 600 and is connected to the second control terminal of the second sub-switch circuit 3012 (e.g., SP4T-VC2).

[0188] Understandably, when the level signal at either port C0 or port C1 is high, the first output of logic circuit 600 outputs a high-level signal as the second control signal. When the level signals at both ports C0 and C1 are low, the first output of logic circuit 600 outputs a low-level signal as the second control signal.

[0189] Similarly, when the level signal at either the output terminal of the first OR gate 501a or the output terminal of the first NOT gate 602a is a high-level signal, the second output terminal of the logic circuit 600 outputs a high-level signal as the first control signal. When the level signals at both ports of the first OR gate 501a and the first NOT gate 602a are low-level signals, the first output terminal of the logic circuit 600 outputs a low-level signal as the first control signal.

[0190] As shown in Table 1, Table 1 is a truth table of the first and second control signals output by the logic circuit 600 and the multiple level signals output by the radio frequency chip 201 in the 2.4G frequency band scenario provided by the embodiments of this application.

[0191] Table 1 Truth Table for 2.4G

[0192] In the table, 1 represents a high level and 0 represents a low level. HPM indicates high power mode (HPM) transmission. LPM indicates low power mode (LPM) transmission. MPM indicates medium power mode (MPM) transmission.

[0193] It is understandable that regardless of whether the sub-switch circuit uses a single-pole multi-throw (SPMD) switch or a single-pole double-throw (SPCD) switch, the SPMD switch includes multiple RF pins as input ports, an ANT pin as a common port (the output pin of the switch), and a VC pin corresponding to each RF pin.

[0194] Taking a single-pole double-throw switch as an example, when the VC1 pin is low and the VC2 pin is high, the analog switch will connect the RF1 pin and the ANT pin; when the VC2 pin is low and the VC1 pin is high, the analog switch will connect the RF2 pin and the ANT pin.

[0195] Taking the second sub-switch circuit 3011 as a single-pole four-throw (SP4T) switch and the first sub-switch circuit 3012 as a single-pole double-throw (SP2T) switch as an example, the SP4T switch has pins SP4T-VC1 and SP4T-VC2. The SP2T switch has SPDT-Vct1 and an ANT pin, as well as multiple RF pins (RF pin 1 to RF pin 4). RF pin 4 corresponds to the fourth terminal 30124 of the second sub-switch circuit 3012. RF pin 3 corresponds to the third terminal 30123 of the second sub-switch circuit 3012. The SP2T switch has an ANT pin and multiple RF pins (RF pin 1 to RF pin 2). RF pin 1 corresponds to the first terminal 30111 of the first sub-switch circuit 3011, and RF pin 2 corresponds to the third terminal 30113 of the first sub-switch circuit 3011.

[0196] Specifically, as shown in Table 1, when the RF circuit is in the transmit state and the C0 port of the RF front-end module 202 receives a high-level signal, the first control signal and the second control signal output by the first output terminal and the second output terminal of the logic circuit 600 are both high-level signals. Referring to Figure 5, the first control signal received by the SPDT-Vct1 pin of the single-pole double-throw switch is a high-level signal. The ANT pin of the single-pole double-throw switch is connected to the RF pin 2 of the single-pole double-throw switch. The first LNA3021 is in a closed state based on the received high-level signal. The second control signal received by the SP4T-VC2 pin of the single-pole four-throw switch is also a high-level signal. In this scenario, the ANT pin of the single-pole four-throw switch is connected to the RF pin 3 of the single-pole four-throw switch, thereby enabling the first transmit channel to conduct.

[0197] When the RF circuit is in the receiving state, as shown in Table 1, if the RF chip 201 outputs a low-level signal through GPIO0, the level signal output by GPIO1 is a high-level signal. The level signal output by GPIO2 is a low-level signal. Then, after processing by the logic circuit 600 shown in Figure 6(a), the first control signal output by the second output terminal of the logic circuit 600 and the second control signal output by the first output terminal are both low-level signals. Referring to Figure 5, the single-pole double-throw switch controls the ANT pin of the single-pole double-throw switch to connect to the RF pin 1 (i.e., the first stationary terminal) of the single-pole double-throw switch based on the first control signal (i.e., the low-level signal). The first LNA3021 is in the on state based on the received low-level signal. The SP4T-VC1 and SP4T-VC2 pins of the single-pole quad-throw switch respectively receive low-level signals. In this scenario, the ANT pin of the single-pole quad-throw switch is connected to the RF pin 4 of the single-pole quad-throw switch, thereby realizing the conduction of the first receiving channel.

[0198] When the RF circuit is in the receiving state, as shown in Table 1, if the level signal output by RF chip 201 through GPIO0 is a low level signal, the level signal output by GPIO1 is a low level signal, and the level signal output by GPIO2 is a low level signal 0, then after processing by the logic circuit 600 shown in Figure 6(a), the first control signal output by the second output terminal of logic circuit 600 is a high level signal, and the second control signal output by the first output terminal of logic circuit 600 is a low level signal. Referring to Figure 5, it can be seen that the single-pole double-throw switch controls the ANT pin of the single-pole double-throw switch to connect to the RF pin 2 of the single-pole double-throw switch based on the high level signal. The first LNA is in the off state based on the received high level signal. When the SP4T-VC1 pin of the single-pole four-throw switch receives a high-level signal and the SP4T-VC2 pin receives a low-level signal, in this scenario, the ANT pin of the single-pole four-throw switch is connected to the RF pin 2 of the single-pole four-throw switch, thereby bypassing the first LNA so that the first RF signal received by the antenna is transmitted to the RF chip 201 through the second receiving channel.

[0199] In another possible embodiment of this application, as shown in Figure 6(b), the logic circuit 600 includes: a first OR gate device 601b, a first NOT gate device 602b, a second OR gate device 603b, and a third OR gate device 604.

[0200] The first input terminal and the second input terminal of the first OR gate device 601b are respectively connected to the C2 port (or the GPIO2 and C0 ports (or the GPIO0 of the RF chip 201) of the RF front-end module 202.

[0201] The output of the first OR gate 601b is connected to the first input of the second OR gate 603b. The input of the first NOT gate 602b is connected to port C1 (or GPIO1 of the RF chip 201). The output of the first NOT gate 602b is connected to the second input of the second OR gate 603b. The output of the second OR gate 603b serves as the second output of the logic circuit 600 and is connected to the first control terminal of the second sub-switch circuit 3012 (e.g., SP4T-VC1), the first control terminal of the first sub-switch circuit 3011 (e.g., SPDT-Vct1), and the control terminal of the first LNA 3021 (e.g., LNA Ven). The output of the first NOT gate 602b is connected to the first input of the third OR gate 604, and the second input of the third OR gate 604 is connected to port C2 of the RF front-end module 202. The output of the third OR gate 604 serves as the first output of the logic circuit 600 and is connected to the second control terminal of the second sub-switch circuit 3012 (e.g., SPDT-Vct2).

[0202] As shown in Figure 6(b), the first control signal output by the second output terminal of the logic circuit 600 is determined by the level signal output by the first OR gate device 601b and the level signal output by the first NOT gate device 602b.

[0203] For example, if at least one of the output signals of the first OR gate 601b and the first NOT gate 602b is a high-level signal, then the first control signal output from the second output of the logic circuit 600 will also be a high-level signal. If both of the output signals of the first OR gate 601b and the first NOT gate 602b are low-level signals, then the first control signal output from the second output of the logic circuit 600 will also be a low-level signal.

[0204] The second control signal output from the first output terminal of logic circuit 600 is determined by the level signal output from the output terminal of the first NOT gate device 602b and the level signal of port C2.

[0205] For example, if at least one of the output signal from the first NOT gate 602b and the level signal from the C2 port of the RF front-end module 202 is a high-level signal, then the first output of the logic circuit 600 outputs a high-level signal as the second control signal. If both of the output signal from the first NOT gate 602b and the level signal from the C2 port of the RF front-end module 202 are low-level signals, then the first output of the logic circuit 600 outputs a low-level signal as the second control signal.

[0206] As shown in Table 2, Table 2 is a truth table of the first and second control signals output by the logic circuit 600 and the multiple level signals output by the radio frequency chip 201 in the 5G band scenario provided by the embodiments of this application.

[0207] Table 2 5G Truth Table

[0208] Specifically, as shown in Table 2, when the RF circuit is in the transmit state, if the GPIO0 output signal of the RF chip 201 is a high-level signal, then the first input terminal of the first OR gate device 601b receives a high-level signal. When the RF chip 201 outputs high-level signals through GPIO1 and GPIO2 respectively, the second input terminal of the first OR gate device 601b and the input terminal of the first NOT gate device 602b both receive high-level signals. After processing by the logic circuit 600 shown in Figure 6(b), the second control signal output by the first output terminal (out1) of the logic circuit 600 is a high-level signal, and the first control signal output by the second output terminal (out2) of the logic circuit 600 is a high-level signal. Referring to Figure 5, as shown in Figure 4(a), the SPDT-Vct1 pin of the first sub-switch circuit 3011 (e.g., a single-pole double-throw switch) receives a high-level signal. The second terminal 30111 of the first sub-switch circuit 3011 (i.e., the ANT pin of the single-pole double-throw switch) is connected to the first terminal 30112 of the first sub-switch circuit 3011 (i.e., the RF pin 1 of the single-pole double-throw switch). The first LNA 3021 is in the off state based on the received high-level signal. The SP4T-VC2 pin of the second sub-switch circuit 3012 (taking a single-pole four-throw switch as an example) and the SP4T-VC1 pin of the second sub-switch circuit 3012 both receive high-level signals. The second terminal 30121 of the second sub-switch circuit 3012 (i.e., the ANT pin of the single-pole four-throw switch) is connected to the first terminal 30122 of the second sub-switch circuit 3012 (i.e., the RF pin 3 of the single-pole four-throw switch), thereby realizing the conduction of the first transmission channel.

[0209] When the RF circuit is in the receiving state, as shown in Table 2, if the RF chip 201 outputs a low-level signal through GPIO0, the first input terminal of the first OR gate device 601b receives a high-level signal. If the RF chip 201 outputs a high-level signal through GPIO1, the input terminal of the first NOT gate device 602b receives a high-level signal. If the RF chip 201 outputs a low-level signal through GPIO2, the second input terminal of the first OR gate device 601b receives a low-level signal. After processing by the logic circuit 600 shown in Figure 6(a), the first control signal output by the second output terminal of the logic circuit 600 is a low-level signal. The second control signal output by the first output terminal of the logic circuit 600 is a low-level signal. Referring to Figure 5, as shown in Figure 4(c), the first sub-switch circuit 3011 controls the second terminal 30112 (i.e., the ANT pin of the single-pole double-throw switch device) connected to the first terminal 30112 (i.e., the RF pin 1 of the single-pole double-throw switch device) based on the received low-level signal. The first LNA3021 is in the ON state based on the received low-level signal. The SP4T-VC1 and SP4T-VC2 pins of the second sub-switch circuit 3012 (e.g., a single-pole four-throw switch) both receive low-level signals. The second terminal 30121 of the second sub-switch circuit 3012 (i.e., the ANT pin of the single-pole four-throw switch) is connected to the third terminal 30123 of the second sub-switch circuit 3012 (RF pin 4 of the single-pole four-throw switch) to enable the first receiving channel. Because the first receiving channel is active, the first LNA3021 is in the ON state, thus the RX GAIN function can be implemented in this scheme.

[0210] When the RF circuit is in the receiving state, as shown in Table 2, if the level signal output by GPIO0 is a high-level signal, then the first input terminal of the first OR gate device 601b receives a high-level signal, the level signal output by GPIO1 is a high-level signal, and the input terminal of the first NOT gate device 602b receives a high-level signal. If the level signal output by GPIO2 is a low-level signal, then the second input terminal of the first OR gate device 601b receives a low-level signal. After processing by the logic circuit 600 shown in Figure 6(a), the first control signal output by the second output terminal of the logic circuit 600 is a high-level signal. The second control signal output by the first output terminal of the logic circuit 600 is a low-level signal. Referring to Figure 5, as shown in Figure 4(b), the first sub-switch circuit 3011 conducts the second terminal 30111 (i.e., the ANT pin of the single-pole double-throw switch device) and the third terminal 30113 (i.e., the RF pin 2 of the single-pole double-throw switch device) of the first sub-switch circuit 3011 based on the high-level signal. The first LNA 3021 is in a closed state based on the received high-level signal. The second sub-switch circuit 3012 (e.g., a single-pole four-throw switch) receives a high-level signal at its SP4T-VC 1 pin, and a low-level control signal at its SP4T-VC 2 pin. In this scenario, the second terminal 30121 of the second sub-switch circuit 3012 (e.g., the ANT pin of the single-pole four-throw switch) is connected to the fourth terminal 30124 of the second sub-switch circuit 3012, thereby enabling the second receiving channel to conduct. Since this scheme can use a combination of a single-pole four-throw switch and a single-pole double-throw switch to bypass the first LNA and thus enable the second receiving channel, the received first RF signal in this scheme is not amplified.

[0211] It is worth noting that the structures shown in Figures (a) and (b) of Figure 6 are only examples of logic circuits. Any logic circuit that can achieve the functions described above can be used as a logic circuit in the embodiments of this application. The embodiments of this application do not limit the specific structure of the logic current. The logic circuit can also adopt other structures besides those shown in Figures (a) and (b) of Figure 6. The embodiments of this application do not limit this.

[0212] In one possible implementation of this application, the logic circuit 600 may also be connected to other circuits besides the RF chip 201. These other circuits provide the logic circuit 600 with multiple level signals output by the RF chip 201, enabling the logic circuit 600 to convert these multiple level signals to obtain a first control signal and a second control signal. For example, the other circuit may be a detection circuit. The detection circuit is used to detect the multiple level signals output by the RF chip 201 via GPIO.

[0213] Figure 6(a) applies to RF chips using the 2.4 GHz band, and Figure 6(b) applies to RF chips using the 5 GHz band. The truth tables shown in Tables 1 and 2 above are merely examples and do not constitute a limitation on the scheme of this application.

[0214] (2) The level signal is provided by the radio frequency chip 201.

[0215] As shown in Figure 7, the RF chip 201 provided in this application embodiment may also have multiple output ports, one of which is connected to the first control terminal of the first switch circuit 301 for outputting a first control signal, one output port is connected to the control terminal of the first gain unit 302 for outputting a second control signal, and another output port is connected to the second control terminal of the first switch circuit 301 for outputting a third control signal.

[0216] For example, the RF chip 201 has a first output port (e.g., GPIO4) and a second output port (GPIO5). The first output port can be connected to the first control terminal of the first switching circuit 301 and the control terminal of the first gain unit 302. The second output port can be connected to the second control terminal of the first switching circuit 301. The first output port of the RF chip 201 is used to output a first control signal (i.e., a third control signal). The second output port of the RF chip 201 is used to output a second control signal.

[0217] For example, referring to Figure 5, as shown in Figure 7, the first output port of the RF chip 201 is connected to the first control terminal (e.g., SP4T-VC1) of the second sub-switch circuit 3012, the first control terminal (e.g., SPDT-Vct1) of the first sub-switch circuit 3011, and the control terminal (e.g., LNA Ven) of the first LNA 3021. The second output port of the RF chip 201 is connected to the second control terminal (e.g., the SP4T-VC2 pin) of the second sub-switch circuit 3012.

[0218] In the 2.4G band scenario, if the RF circuit is in the transmit state, the RF chip 201 is used to output a high-level signal through the first output port as a second control signal, and to output a high-level signal through the second output port as a first control signal and a third control signal. As shown in Figure 4(a), the high-level signal is used to trigger the second terminal of the first sub-switch circuit 3011 to connect to the third terminal 30113 of the first sub-switch circuit 3011, and to trigger the first LNA 3021 to turn off, and to trigger the second terminal 30121 of the second sub-switch circuit 3012 to connect to the first terminal 30122 of the second sub-switch circuit 3012.

[0219] When the RF circuit is in receiving mode, to achieve the Rx gain function, the RF chip 201 outputs a low-level signal through the first output port as a second control signal, and outputs a low-level signal through the second output port as a first control signal and a third control signal. As shown in Figure 4(c), the low-level signal is used to trigger the second terminal 30111 of the first sub-switch circuit 3011 to be connected to the first terminal 30112 of the first sub-switch circuit 3011, and the first LNA 3021 is in the on state based on the received low-level signal. The level signals received by the SP4T-VC 1 pin and SP4T-VC 2 pin of the second sub-switch circuit 3012 are also low-level signals. In this scenario, the second terminal 30121 of the second sub-switch circuit 3012 is connected to the third terminal 30121 of the second sub-switch circuit 3012.

[0220] When the RF circuit is in the receiving state, in order to realize the Rx bypass function, the RF chip 201 is used to output a high-level signal through the first output port as a second control signal, and to output a low-level signal through the second output port as a first control signal and a third control signal.

[0221] As shown in Figure 4(b), the second terminal 30111 of the first sub-switch circuit 3011 is connected to the third terminal 30113 of the first sub-switch circuit 3011. The first LNA 3021 is in the off state based on the received high-level signal. The SP4T-VC 1 pin of the second sub-switch circuit 3012 receives a low-level signal, and the SP4T-VC 2 pin receives a high-level signal. In this scenario, the second terminal 30121 of the second sub-switch circuit 3012 is connected to the fourth terminal 30124 of the second sub-switch circuit 3012.

[0222] In the radio frequency circuits shown in Figures 4 to 7 of this application embodiment, there is an inter-board connection between the first circuit board 200 and the second circuit board 300. This inter-board connection includes at least the following transmission lines: a radio frequency signal transmission line RF_TX (used to transmit a second radio frequency signal, i.e., the TX signal), a radio frequency signal transmission line RF_Rx (used to transmit a first radio frequency signal, i.e., the RX signal), a power transmission line, and a logic control signal transmission line.

[0223] For example, the first circuit board 200 and the second circuit board 300 can be connected via PFC, as shown in Figure 8(a). The FPC includes at least an RF signal transmission line RF_TX, an RF signal transmission line RF_Rx, a logic control signal transmission line (e.g., a transmission line for transmitting the level signal of RXFEM_C0, a transmission line for transmitting the level signal of RXFEM_C1), and power supply lines (e.g., Vdd) for the first switch circuit 301 and the first LNA 302. Alternatively, as shown in Figure 8(b), the first circuit board 200 and the second circuit board 300 can also be connected via FPC+Cable. For example, the FPC can deploy logic control signals (RXFEM_C0, RxFEM_C1), the power supply lines for the first switch circuit 301 and the first LNA 302. One cable line is used as the RF signal transmission line RF_TX, and another cable line is used as the RF signal transmission line RF_Rx.

[0224] For example, the first circuit board 200 or the second circuit board 300 can be connected to the FPC via a BTB (Board-to-Board) connector.

[0225] In another possible embodiment of this application, as shown in FIG9, the radio frequency circuit may further include a second switching circuit 700. The embodiment shown in FIG9 differs from the embodiments shown in FIGS. 4-8 in that a second switching circuit 700 is further provided between the first circuit board 200 and the second circuit board 300. The second switching circuit 700 is used to connect the first communication port of the first switching circuit 301 to the second port 2022 of the radio frequency front-end module 202, or to connect the first communication port of the first switching circuit 301 to the receiving port 2012 of the radio frequency chip 201. That is, the second switching circuit 700 is used to switch the channel between the second port 2022 of the radio frequency front-end module 202 and the first communication port of the first switching circuit 301, and the channel between the first communication port of the first switching circuit 301 and the receiving port 2012 of the radio frequency chip 201.

[0226] Specifically, the first terminal 7001 and the second terminal 7002 of the second switching circuit 700 are respectively connected to the second port 2022 of the RF front-end module 202 and the receiving port 2012 of the RF chip 201. The third terminal 7003 of the second switching circuit 700 is connected to the first communication port of the first switching circuit 301.

[0227] In one implementation of this application, when the RF circuit is in the transmitting state, the second switch circuit 700 is used to enable the channel between the second port 2022 of the RF front-end module 202 and the first communication port of the first switch circuit 301. The first switch circuit 301 is used to enable the first transmission path, so that the second RF signal is transmitted to the first transmission channel within the RF front-end module 202, and then transmitted to the antenna module via the first transmission channel. That is, in the circuit shown in FIG10(a), the transmission channel between the transmitting port 2011 of the RF chip 201 and the antenna module 400 includes the second transmission channel and the first transmission channel. The second transmission channel and the first transmission channel are connected through the second switch circuit 700.

[0228] In one implementation of this application, when the radio frequency circuit is in the receiving state, the second switching circuit 700 is used to enable the conduction of the channel between the first communication port of the first switching circuit 301 and the receiving port 2012 of the radio frequency chip 201. The first switching circuit 301 is used to enable the conduction of the first receiving channel or the second receiving channel, so that the first radio frequency signal is transmitted after being amplified by the first receiving channel, as shown in Figure 10(c), or to enable the conduction of the second receiving channel, so that the first radio frequency signal is transmitted through the first receiving channel bypassing the first gain unit 302, as shown in Figure 10(b).

[0229] Specifically, in the radio frequency circuits shown in Figures 9 and 10, when the radio frequency circuit is in the transmitting state, the control terminal of the second switching circuit 700 is also used to receive a fourth control signal. This fourth control signal is used to trigger the second switching circuit 700 to connect the third terminal 7003 of the second switching circuit 700 to the first terminal 7001 of the second switching circuit 700, so as to open the channel between the second port of the radio frequency front-end module and the first communication port of the first switching circuit, as shown in Figure 10(a).

[0230] For example, when the radio frequency circuit is in the receiving state, the control terminal of the second switching circuit 700 is also used to receive a fifth control signal. The fifth control signal is used to trigger the second switching circuit 700 to connect the third terminal 7003 of the second switching circuit 700 to the second terminal 7002 of the second switching circuit 700, as shown in (b) or (c) of Figure 10.

[0231] In one implementation of this application, the second switching circuit 700 can be deployed on the first circuit board 200. By deploying the second switching circuit 700, signal reception and transmission can be achieved between the first circuit board 200 and the second circuit board 300 using a single transmission line.

[0232] In one possible embodiment of this application, the aforementioned fifth control signal and fourth control signal can be provided by a radio frequency (RF) circuit. For example, they can be provided by the RF chip 201 in the RF circuit, or by the processor in the RF circuit, or by other devices; this embodiment of the application does not limit this.

[0233] For example, an output port (such as GPIO6) of the RF chip 201 is connected to the control terminal of the second switching circuit 700. When the RF circuit is in the transmitting state, the RF chip 201 is used to output a fourth control signal to the second switching circuit 700. The fourth control signal is used to control the second switching circuit to turn on the channel between the second port of the RF front-end module and the first communication port of the first switching circuit. The first communication port is connected to the first transmitting channel.

[0234] When the radio frequency circuit is in the receiving state, the radio frequency chip 201 is used to output a fifth control signal to the second switch circuit 700. The fifth control signal is used to control the second switch circuit to open the channel between the first communication port of the first switch circuit 301 and the receiving port 2012 of the radio frequency chip 201. The first communication port is connected to the first receiving channel or the second receiving channel.

[0235] For example, when the RF circuit is in transmit mode, the fourth control signal can be level signal 1, and when in receive mode, the fifth control signal can be level signal 2. One of level signal 1 and level signal 2 can be a high-level signal, and the other can be a low-level signal.

[0236] In one possible embodiment of this application, the first control terminal of the first switching circuit 301 is further configured to receive a sixth control signal, and the control terminal of the first gain unit 302 is configured to receive a seventh control signal. The sixth control signal and the fifth control signal may be the same control signal or different control signals. The sixth and seventh control signals may be provided by the RF chip 201, by the processor in the RF circuit, or by other devices; this embodiment of the application does not limit this provision.

[0237] The sixth control signal is used to control the first gain unit 302 to turn on or off, and the seventh control signal is used to control the first switching circuit 301 to switch between the first transmitting channel, the second receiving channel, or the first receiving channel.

[0238] Specifically, the output port (GPIO7) of the RF chip 201 is used to output the seventh control signal or the sixth control signal to the first control terminal of the first switching circuit 301 and the control terminal of the first gain unit 302. The sixth control signal or the sixth control signal can be a level signal, such as a high-level signal or a low-level signal, and this embodiment of the application does not limit it.

[0239] The structure of the first switching circuit 301 in the embodiment shown in FIG9 will be described below.

[0240] In one example of this application, as shown in FIG9, the first switching circuit 301 includes a third sub-switching circuit 9011 and a fourth sub-switching circuit 9012. The first gain unit 302 may be a third LNA 9013.

[0241] As shown in Figure 9, the second terminal 90111 of the third sub-switch circuit 9011 serves as the first communication port of the first switch circuit 301 and is connected to the third terminal 7003 of the second switch circuit 700.

[0242] The third terminal 90113 of the third sub-switch circuit 9011 is connected to the third terminal 90123 of the fourth sub-switch circuit 9012. The first terminal 90112 of the third sub-switch circuit 9011 is connected to the output terminal of the third LNA 9013. The input terminal of the third LNA 9013 is connected to the first terminal 90122 of the fourth sub-switch circuit 9012. The second terminal 90121 of the fourth sub-switch circuit 9012 is connected to the antenna module 400. Specifically, the second terminal 90121 of the fourth sub-switch circuit 9012 is connected to the antenna module 400 through the filter 500. The first terminal 7001 of the second switch circuit 700 is connected to the second port 2022 of the RF front-end module 202. The second terminal 7002 of the second switch circuit 700 is connected to the receiving port 2012 of the RF chip 201.

[0243] Specifically, when the RF circuit is in the transmit state, as shown in Figure 10(a), the first and second terminals of the third switching circuit 2025 are turned on to enable the second transmit channel, and the first terminal 7001 and the third terminal 7003 of the second switching circuit 700 are also turned on. The third terminal 90113 of the third sub-switching circuit 9011 is connected to the second terminal 90111 of the third sub-switching circuit 9011. The third terminal 90123 of the fourth sub-switching circuit 9012 is connected to the second terminal 90121 of the fourth sub-switching circuit 9012 to enable the first transmit channel.

[0244] In the transmission scenario shown in Figure 10(a), the second radio frequency signal is emitted by the radio frequency chip 201 through the transmission port 2011 and then enters the second PA 2023 for amplification. The amplified first radio frequency signal enters the third switch circuit 2025 through the first terminal of the third switch circuit 2025 and is then transmitted to the first terminal 7001 of the second switch circuit 700. Since the first terminal of the second switch circuit 700 is connected to the third terminal (moving terminal) of the second switch circuit 700, the amplified first radio frequency signal is transmitted to the third sub-switch circuit 9011 through the transmission line between the third terminal of the second switch circuit 700 and the third terminal (moving terminal) of the third sub-switch circuit 9011. Since the first transmission channel is turned on, the amplified first radio frequency signal is transmitted to the antenna module 400 through the first transmission channel and is then radiated by the antenna module 400.

[0245] Specifically, when the RF circuit is in the receiving state, as shown in Figure 10(b), to enable the second receiving channel, the second terminal 90121 of the fourth sub-switch circuit 9012 is connected to the third terminal 90123 of the fourth sub-switch circuit 9012. The second terminal 90111 of the third sub-switch circuit 9011 is connected to the third terminal 90123 of the third sub-switch circuit 9011. The third terminal 90123 of the third sub-switch circuit 9011 is connected to the third terminal 90123 of the fourth sub-switch circuit 9012. The third terminal 7030 of the second switch circuit 700 and the second terminal 7002 of the second switch circuit 700 are connected to enable the second receiving channel.

[0246] In the receiving scenario shown in Figure 10(b), the antenna module 400 receives electromagnetic waves and converts them into a first radio frequency signal. The first radio frequency signal passes through the filter 500 and is then transmitted to the radio frequency chip 201 through the second receiving channel.

[0247] It is understood that in the receiving scenario shown in Figure 10(b), the second receiving channel includes: the channel between the antenna module 400 and the second terminal 90121 of the fourth sub-switch circuit 9012, the channel between the third terminal 90123 of the fourth sub-switch circuit 9012 and the third terminal 90113 of the third sub-switch circuit 9011, the channel between the second terminal 90111 of the third sub-switch circuit 9011 and the third terminal 7003 of the second switch circuit 700, and the channel between the second terminal 7002 of the second switch circuit 700 and the receiving port 2012 of the RF chip 201.

[0248] Specifically, when the RF circuit is in the receiving state, as shown in Figure 10(c), to enable the first receiving channel, the second terminal 90121 of the fourth sub-switch circuit 9012 is connected to the first terminal 90122 of the fourth sub-switch circuit 9012. The second terminal 90111 of the third sub-switch circuit 9011 is connected to the first terminal 90112 of the third sub-switch circuit 9011. The third terminal 7003 of the second switch circuit 700 is connected to the second terminal 7002 of the second switch circuit 700, thereby enabling the first receiving channel to be turned on.

[0249] In the receiving scenario shown in Figure 10(c), the antenna module 400 receives electromagnetic waves and converts them into a first radio frequency (RF) signal. This first RF signal passes through a filter 500 and enters the second circuit board 300, where it is transmitted via a first receiving channel. After being amplified (e.g., by a third LNA 9013), the first RF signal enters the RF chip 201 via the first receiving channel between the second terminal 90111 of the third sub-switch circuit 9011 and the receiving port 2012 of the RF chip 201.

[0250] It is understood that in the receiving scenario shown in Figure 10(c), the first receiving channel includes: the channel between the antenna module 400 and the second terminal 90121 of the fourth sub-switch circuit 9012, the channel between the first terminal of the fourth sub-switch circuit 9012, the third LNA 9013 and the first terminal 90112 of the third sub-switch circuit 9011, the channel between the second terminal 90111 of the third sub-switch circuit 9011 and the third terminal 703 of the second switch circuit 700, and the channel between the second terminal 7002 of the second switch circuit 700 and the receiving port 2012 of the RF chip 201.

[0251] Specifically, in the radio frequency circuits shown in Figures 9 and 10, the control terminal of the first switching circuit 301 may include the control terminal of the third sub-switching circuit 9011 and the control terminal of the fourth sub-switching circuit 9012.

[0252] The control terminals of the third sub-switch circuit 9011 (e.g., SPDT-Vct1) and the fourth sub-switch circuit 9012 (e.g., SPDT-Vct1) are also used to receive a sixth control signal. This sixth control signal can be control signal a or control signal b. One of the control signal a or control signal b can be a high-level signal, and the other can be a low-level signal; this embodiment does not limit this.

[0253] Specifically, when the radio frequency circuit is in the transmit state, control signal a is used to trigger the second terminal 90111 of the third sub-switch circuit 9011 to be connected to the third terminal 90113 of the third sub-switch circuit 9011, and control signal a is used to trigger the second terminal 90121 of the fourth sub-switch circuit 9012 to be connected to the third terminal 90123 of the fourth sub-switch circuit 9012, as shown in Figure 10(a).

[0254] Specifically, when the radio frequency circuit is in the receiving state, the control signal a is used to trigger the second terminal 90111 of the third sub-switch circuit 9011 to be connected to the third terminal 90113 of the third sub-switch circuit 9011, and the control signal a is used to trigger the second terminal 90121 of the fourth sub-switch circuit 9012 to be connected to the third terminal 90123 of the fourth sub-switch circuit 9012, as shown in (b) of Figure 10.

[0255] Alternatively, when the RF circuit is in the receiving state, the control signal b is used to trigger the second terminal 90111 of the third sub-switch circuit 9011 to connect to the first terminal 90112 of the third sub-switch circuit 9011, and the control signal b is used to trigger the second terminal 90121 of the fourth sub-switch circuit 9012 to connect to the first terminal 90122 of the fourth sub-switch circuit 9012, as shown in (c) of Figure 10.

[0256] Specifically, in the RF circuits shown in Figures 9 and 10, the control terminal of the third LNA9013 is also used to receive a seventh control signal, which is used to control the third LNA9013 to turn on or off. For example, when the RF circuit is in the transmitting state, the second control signal is used to control the third LNA9013 to turn off. When the RF circuit is in the receiving state, the second control signal is used to control the third LNA9013 to turn on.

[0257] Specifically, in the scenario of implementing RX gain, this seventh control signal is used to control the third LNA9013 to turn on. In the scenario of implementing RX bypass function, this seventh control signal is used to control the third LNA9013 to turn off.

[0258] It is worth noting that in the embodiments shown in Figures 9 and 10, the first transmitting channel and the second receiving channel can be the same channel.

[0259] In one possible embodiment of this application, the aforementioned sixth and seventh control signals can be provided by the RF chip 201. For example, the control terminals of the fourth sub-switch circuit 9012, the third LNA 9013, and the third sub-switch circuit 9011 can be connected to the output port GPIO7 of the RF chip 201. The control terminal of the second switch circuit 700 can also be connected to GPIO6 of the RF chip 201. Either GPIO6 or GPIO7 is used to output the corresponding control signal.

[0260] In another possible implementation of this application, the sixth and seventh control signals mentioned above can also be provided by a second logic circuit. The second logic circuit can output corresponding control signals according to the level signals provided by the RF chip 201 to the C0 to C2 ports of the RF front-end module 202. This application embodiment does not limit this.

[0261] In one possible embodiment of this application, as shown in Figures 10 and 9, the inter-board connection between the first circuit board 200 and the second circuit board 300 includes at least the following transmission lines: signal transmission lines (for transmitting a second radio frequency signal (such as a Wi-Fi signal) and / or transmitting a first radio frequency signal (such as a Wi-Fi signal)), power transmission lines, and logic control signal transmission lines.

[0262] The power transmission line is used to provide power to the first switching circuit 301 and the first gain unit 302. For example, one end of the power transmission line is connected to a power source, and the other end is connected to the power source terminals of the first sub-switching circuit 9011, the second sub-switching circuit 9012, and the third LNA 9013, respectively.

[0263] The aforementioned signal transmission line is used to transmit the second radio frequency signal emitted by the radio frequency chip 201 to the second circuit board 300, and to transmit the first radio frequency signal received by the antenna module 400. One end of the signal transmission line is connected to the third terminal 7003 of the second switching circuit 700. The other end of the signal transmission line is connected to the second terminal 90111 of the first sub-switching circuit 9011 on the second circuit board 300. Alternatively, the other end of the signal transmission line is connected to a signal transmission port on the second circuit board 300. This signal transmission port is connected to the first receiving channel, the second receiving channel, or the first transmitting channel.

[0264] The aforementioned signal transmission line can be a single line. Alternatively, it can include two lines (e.g., signal transmission line 1 and signal transmission line 2). Signal transmission line 1 is used to transmit the second radio frequency signal emitted by the radio frequency chip 201 to the second circuit board 300. Signal transmission line 2 is used to transmit the first radio frequency signal from the second circuit board 300 to the first circuit board 200.

[0265] If the aforementioned signal transmission line is a single line, then one end of the signal transmission line is connected to the third terminal 7003 of the second switching circuit 700, and the other end is connected to the signal transmission port on the second circuit board 300. This signal transmission port is connected to either the first receiving channel or the second receiving channel.

[0266] If the aforementioned signal transmission lines may include two signal transmission lines, then the second switching circuit 700 can be implemented using two switching devices (e.g., switching device A and switching device B). One end of switching device A is connected to the second port 2022, and the other end of switching device A is connected to one end of signal transmission line 1. The other end of signal transmission line 1 is connected to signal transmission port 1 on the second circuit board 300. Signal transmission port 1 is connected to the first transmitting channel. One end of signal transmission line 2 is connected to the second port 2022 of the RF front-end module 202 via switching device B, and the other end of signal transmission line 2 is connected to signal transmission port 2 on the second circuit board. Signal transmission port 2 is connected to either the first receiving channel or the second receiving channel. When the RF circuit is in the transmitting state, switching device A is turned on, and switching device B is turned off. When the RF circuit is in the receiving state, switching device B is turned on, and switching device A is turned off.

[0267] The logic control signal transmission line provides level signals to the first control terminal of the first sub-switch circuit 9011, the first control terminal of the second sub-switch circuit 9012, and the control terminal of the third LNA 9013. One end of the logic control signal transmission line can be connected to the output port (GPIO6 or GPIO7) of the logic circuit or the RF chip 201. The other end of the logic control signal transmission line can be connected to the first control terminal of the first sub-switch circuit 9011, the first control terminal of the second sub-switch circuit 9012, and the control terminal of the third LNA 9013. The logic control signal transmission line may include one or more lines; this embodiment does not limit this.

[0268] For example, the connection between the first circuit board 200 and the second circuit board 300 can be achieved using an FPC. Alternatively, the connection between the first circuit board 200 and the second circuit board 300 can be entirely achieved using cable lines. Or, the connection between the first circuit board 200 and the second circuit board 300 can be achieved using both FPC and cable lines.

[0269] In the embodiments shown in Figures 10 and 9, compared to the embodiments shown in Figures 3 to 8, the addition of a second switching circuit 700 (e.g., an SPDT switch) between the first and second circuit boards allows for switching between the receiving and transmitting channels. This enables the transmission and reception of radio frequency signals to be achieved with only one radio frequency transmission line between the first circuit board 200 and the second circuit board 300. This increases the flexibility and feasibility of the overall board-to-board connection method.

[0270] Comparing Figure 11(a) and Figure 11(b), in the scheme shown in Figure 11(a), a secondary PCB board is arranged on the antenna module 400 side. The main PCB board and the secondary PCB board are connected by an FPC. Circuit devices for amplifying the radio frequency signal are arranged on the secondary PCB board.

[0271] Figure 11(b) is a schematic diagram of the connection between the antenna module 400 and the RF front-end module 202 in the related art. If the RF front-end module 202 and the RF chip 201 are deployed on the main PCB board, which is far from the antenna module, then the output of the RF front-end module needs to be connected to the antenna module 400 through a relatively long cable. In the 2.4 GHz band, the solution shown in Figure 11(a) improves the RX sensitivity by 2.1 dB compared to the solution shown in Figure 11(b). Furthermore, in the solution shown in Figure 11(a) of this application, the connection between the main PCB board and the sub-PCB board via FPC can achieve an inter-board connection loss of 1.6 dB. In contrast, the line loss in Figure 11(b) where the main PCB board and the antenna module are connected via a long cable is approximately 0.5 dB.

[0272] In another embodiment of this application, a terminal device is provided, which may include the radio frequency circuits shown in Figures 3 to 10.

[0273] Optionally, the terminal device may also include an antenna module 400. For example, the first circuit board 200 is located on the side of the terminal device away from the antenna module 400. The second circuit board 300 is located on the side of the terminal device closer to the antenna module.

[0274] Case 2) The receiving port 2012 of the RF chip 201 is connected to the RF front-end module 202.

[0275] Figure 12 shows the structure of another radio frequency circuit provided in an embodiment of this application. The difference between the radio frequency circuit shown in Figure 12 and the radio frequency circuits shown in Figures 4 to 10 is as follows:

[0276] In the RF circuits shown in Figures 4-10, the receiving port 2012 of the RF chip 201 is connected to the second circuit board 300, meaning the first RF signal received by the antenna module 400 can be transmitted to the RF chip 201 without passing through the RF front-end module 202. However, in the RF circuit shown in Figure 12, the receiving port 2012 of the RF chip 201 is connected to the third port 2026 of the RF front-end module 202. Thus, the first RF signal received by the antenna module 400 enters the RF front-end module 202 after passing through the receiving channel (i.e., the first or second receiving channel described below) within the second circuit board 300. The first RF signal then enters the RF chip 201 through the receiving channel (the fifth or sixth receiving channel described below) within the RF front-end module 202.

[0277] As shown in Figure 12, the radio frequency circuit includes a first circuit board 200 and a second circuit board 300, wherein the first circuit board 200 is connected to the second circuit board 300, and the second circuit board 300 is used to connect the antenna module 400. In other words, the first circuit board 200 is connected to the antenna module 400 through the second circuit board 300.

[0278] The first circuit board 200 may include a radio frequency (RF) front-end circuit. The RF front-end circuit may include an RF IC 201 and a RF front-end module (FEM) 202.

[0279] As shown in Figure 12, the RF chip 201 has a receiving port 2012. The RF front-end module 202 has a first port 2021, a second port 2022, and a third port 2026. The receiving port 2012 of the RF chip 201 is connected to the third port 2026 of the RF front-end module 202. The second port of the RF front-end module 202 is connected to the first communication port of the first switching circuit 301.

[0280] The second circuit board 300 includes a first gain unit 302 and a first switching circuit 301. The first switching circuit 301 is used to switch between a third receiving channel and a fourth receiving channel. Specifically, the first switching circuit 301 is used to enable the third receiving channel between the second port 2022 of the RF front-end module 202, the first gain unit 302, and the antenna module 400. Alternatively, the first switching circuit 301 is used to bypass the first gain unit 302 to enable the fourth receiving channel between the second port 2022 of the RF front-end module 202 and the antenna module 400.

[0281] Specifically, the third receiving channel is the channel between the antenna module 400 and the second port 2022 of the RF front-end module 202 that passes through the first gain unit 302, and the fourth receiving channel is the channel between the antenna module 400 and the second port 2022 of the RF front-end module 202 that does not pass through the first gain unit 302.

[0282] In one possible embodiment of this application, the transmit port 2011 of the RF chip 201 is connected to the first port 2021 of the RF front-end module 202. In this way, the second RF signal transmitted by the RF chip 201 through the transmit port 2011 can enter the RF front-end module 202 through the first port 2021 and be transmitted through the second port 2022 of the RF front-end module 202.

[0283] In one possible embodiment of this application, on the one hand, the second port 2022 of the radio frequency front-end module 202 is connected to the antenna module 400, so the second radio frequency signal can be transmitted to the antenna module 400 through the second port 2022.

[0284] In one possible embodiment of this application, the second circuit board 300 also has a first transmission channel. On the other hand, the second port 2022 of the RF front-end module 202 is connected to the antenna module 400 through the first transmission channel. That is, one end of the first transmission channel is connected to the second port 2022 of the RF front-end module 202, and the other end is connected to the antenna module 400. In this way, the second RF signal can enter the second circuit board 300 through the second port 2022 and be transmitted to the antenna module 400 through the first transmission channel.

[0285] In one possible embodiment of this application, the first switching circuit 301 is specifically used to switch between the first transmitting channel, the fourth receiving channel, and the third receiving channel.

[0286] The first transmitting channel is used to transmit the second radio frequency signal output by the radio frequency chip 201, and the fourth receiving channel is used to transmit the first radio frequency signal received by the antenna module 400 to the radio frequency front-end module 202. The third receiving channel is used to transmit the first radio frequency signal, after being amplified by the first gain unit 302, to the radio frequency front-end module 202.

[0287] In one possible embodiment of this application, the first transmitting channel and the fourth receiving channel may be the same channel, and this application does not limit this.

[0288] This application does not limit the specific structure of the first switching circuit 301 or the specific connection relationship between the first switching circuit 301 and the first gain unit 302. In practice, as long as the first switching circuit 301 can cooperate with the first gain unit 302 to form a communication channel (i.e., the fourth receiving channel) on the second circuit board 300 to receive the first radio frequency signal, or to form a third receiving channel on the second circuit board, it is acceptable.

[0289] Optionally, the first switching circuit 301 can also be used to enable the conduction of the first transmission channel between the second port 2022 of the RF front-end module 202 and the antenna module 400.

[0290] For example, the first switching circuit 301 may further include a switching device X, which is connected between the second port 2022 of the RF front-end module 202 and the antenna module 400. When the RF circuit is in the transmitting state, the switching device X is closed to enable the first transmitting channel; when the RF circuit is in the receiving state, the switching device X can be opened to disable the first transmitting channel. For example, the first switching circuit 301 may further include a switching device Y and / or a switching device Z, where switching device Y is connected between the second port 2022 of the RF front-end module 202 and the first gain unit 302, and switching device Z is connected between the first gain unit 302 and the antenna module 400. When the RF circuit is in the receiving state, switching devices Y and Z are closed to enable the third receiving channel to achieve signal gain. The first switching circuit 301 may further include a switching device M, which is connected in series between the second port 2022 of the RF front-end module 202 and the antenna module 400 to bypass the first gain unit 302, thereby forming a fourth receiving channel. When the RF circuit is in receive mode, the switch M can be closed to enable the fourth receive channel. In scenarios where gain is achieved during reception, the switch M is open, thus disabling the fourth receive channel.

[0291] The specific structure of the first switching circuit 301 involved in the embodiments of this application will be described below with reference to FIG13 or FIG14. As shown in FIG13 or FIG14, the first switching circuit 301 includes a third sub-switching circuit 9011 and a fourth sub-switching circuit 9012. The first gain unit 302 can be a third LNA 9013.

[0292] As shown in Figure 13, the structure and connection relationship of the third sub-switch circuit 9011, the fourth sub-switch circuit 9012, and the third LNA 9013 can be referred to the structure and connection relationship shown in Figure 10 or Figure 9, and will not be repeated here.

[0293] In one embodiment of this application, as shown in FIG12 or FIG13, the radio frequency circuit further includes a filter 500, which is connected in series between the second circuit board 300 and the antenna module 400.

[0294] It is understandable that in scenarios where the radio frequency circuit also includes a filter 500, the second circuit board 300 is also connected to the antenna module 400 through the filter 500.

[0295] In one possible embodiment of this application, the radio frequency front-end module 202 has at least one or more of the following functions: amplifying a second radio frequency signal transmitted by the radio frequency chip 201 through the transmit port 2011; transmitting the amplified second radio frequency signal through the second port 2022 of the radio frequency front-end module 202; and amplifying a first radio frequency signal received through the second port 2022 of the radio frequency front-end module 202.

[0296] Referring to Figure 13, which shows the structure of a radio frequency circuit provided in an embodiment of this application, the radio frequency front-end module 202 in Figure 13 includes: a second power amplifier PA2023, a second LNA2024, and a third switching circuit 2025.

[0297] Integrating the PA, the second LNA2024, and the switching devices into the RF front-end module 202 can reduce the area occupied by the PA and the switching devices and effectively improve the integration of the circuit.

[0298] In this configuration, the second power amplifier PA2023 is connected in series between the transmit port 2011 of the RF chip 201 and the first terminal 20251 of the third switching circuit 2025. Specifically, the input terminal of the second power amplifier PA2023 is connected to the first port 2021 of the RF front-end module 202. The output terminal of the second power amplifier PA2023 is connected to the first terminal 20251 of the third switching circuit 2025. The second terminal 20252 of the third switching circuit 2025 serves as the second port 2022 of the RF front-end module 202. Alternatively, the second terminal 20252 of the third switching circuit 2025 is connected to the second port 2022 of the RF front-end module 202. The third terminal 20253 of the third switching circuit 2025 is connected to the input terminal of the second LNA 2024. The output terminal of the second LNA 2024 is connected to the third port 2026 of the RF front-end module 202, or alternatively, the output terminal of the second LNA 2024 serves as the third port 2026 of the RF front-end module 202.

[0299] Understandably, the third switching circuit 2025 is primarily used to switch between the second transmit channel and the fifth receive channel within the RF front-end module 202. The second transmit channel refers to the channel between the transmit port 2011 of the RF chip 201 and the second port 2022 of the RF front-end module 202. The second power amplifier PA 2023 is located on the second transmit channel. The fifth receive channel refers to the channel between the receive port 2012 of the RF chip 201 and the second port 2022 of the RF front-end module 202. The second LNA 2024 is located on the fifth receive channel. The second LNA 2024 is used to perform gain processing on the RF signal transmitted via the fifth receive channel, and the fifth receive channel is used to ensure that the first RF signal, after being amplified by the second LNA 2024, is transmitted to the RF chip.

[0300] Optionally, the third switching circuit 2025 is also used to switch the sixth receiving channel. The sixth receiving channel is used to connect the receiving port 2012 of the RF chip 201 to the second port 2022 of the RF front-end module 202. The sixth receiving channel is used to allow the first RF signal to bypass the second LNA 2024 and be transmitted to the RF chip 201.

[0301] The third switching circuit 2025 in this embodiment can be controlled by the RF chip 201 or the processor in the RF circuit. That is, the RF chip 201 or the processor provides a control signal to the third switching circuit 2025 to control the switching of the second transmitting channel and the fifth receiving channel in the RF front-end module 202.

[0302] In Figure 13, the third switching circuit 2025 is taken as a single-pole double-throw switch. In practice, the third switching circuit 2025 can also be a single-pole multi-throw switch, or it can be combined with two or more other single-pole single-throw switches to achieve the above function. When the third switching circuit 2025 is a single-pole multi-throw switch, the common port of the single-pole multi-throw switch serves as the second terminal 20252 of the third switching circuit 2025. One input port of the single-pole multi-throw switch serves as the first terminal 20251 of the third switching circuit 2025. The other input port of the single-pole multi-throw switch serves as the second terminal 20253 of the third switching circuit 2025.

[0303] For example, as shown in Figure 14, which illustrates another RF circuit structure of this application, the difference between Figure 13 and Figure 14 is that in Figure 13, the third switching circuit 2025 can be implemented using a single-pole multi-throw switch or a single-pole double-throw switch, while in Figure 14, the third switching circuit 2025 can be formed by combining multiple switching devices. For example, as shown in Figure 14, the third switching circuit 2025 may also include switching device 1 and switching device 2. Switching device 1 is connected in series between the output terminal of the second power amplifier PA2023 and the second port 2022. Switching device 2 is connected in series between the second port 2022 and the input terminal of the second LNA 2024.

[0304] In one possible embodiment of this application, both switching device 1 and switching device 2 can be implemented using single-pole single-throw switching devices. It is worth noting that Figures 14 and 13 respectively exemplarily illustrate two implementations of the third switching circuit 2025, and do not constitute a limitation on the structure of the third switching circuit 2025. In specific implementations, any structure of the third switching circuit 2025 can be used to achieve the functions of this application, and this application embodiment does not limit this.

[0305] In one possible embodiment of this application, the third switching circuit 2025 is further used to bypass the second LNA 2024 so that a sixth receiving channel can be formed within the RF front-end module 202. This sixth receiving channel is a channel between the receiving port 2012 of the RF chip 201 and the second port 2022 of the RF front-end module 202, and bypasses the second LNA 2024, thereby achieving bypass of the second LNA 2024. Thus, the RF signal transmitted through the sixth receiving channel does not receive gain in the RF front-end module 202. For example, in this scenario, the third switching circuit 2025 may also have a fourth port, which is connected to the receiving port 2012 or to the third port 2026 of the RF front-end module 202. For example, the third switching circuit 2025 may employ a single-pole triple-throw switch.

[0306] Of course, the third switching circuit 2025 may also include: a second switching device 2027.

[0307] In one possible embodiment of this application, the radio frequency circuit shown in FIG13 or FIG14 may further include a second switching device 2027, and the second LNA 2024 may be connected in parallel with the second switching device 2027. The second switching device 2027 is used to bypass the second LNA 2024.

[0308] When the second switching device 2027 is off, the second LNA 2024 is not bypassed. The first radio frequency signal that enters the radio frequency front-end module 202 through the second port 2022 is transmitted through the fifth receiving channel and is amplified by the second LNA 2024 before being transmitted to the radio frequency chip 201.

[0309] When the second switching device 2027 is closed, the second LNA 2024 is bypassed. With the second switching device 2027 bypassing the second LNA 2024, the first radio frequency signal that enters the radio frequency front-end module 202 through the second port 2022 is transmitted to the radio frequency chip 201 through the sixth receiving channel.

[0310] In one possible implementation of this application, the second switching device 2027 can be controlled by the radio frequency chip 201, that is, the second switching device 2027 can be connected to an output port (such as GPIO3) of the radio frequency chip 201, and the radio frequency chip 201 is used to provide a switching signal to the second switching device 2027 through the output port.

[0311] Specifically, when the RF circuit is in receiving mode and the RF front-end module 202 is not needed to achieve receiving gain, the switching signal is used to instruct the second switching device 2027 to switch to the sixth receiving channel. When the RF circuit is in receiving mode and the RF front-end module 202 is needed to achieve receiving gain, the switching signal is used to instruct the second switching device 2027 to switch to the fifth receiving channel. For example, the switching signal can be a high-level signal or a low-level signal.

[0312] It is worth noting that in the scenario where the third switching circuit 2025 adopts a single-pole multi-throw switch, the third switching circuit 2025 can bypass or not bypass the second LNA 2024 based on the level signal provided by the RF chip 201.

[0313] The following describes the workflow within the RF front-end module 202, in both transmitting and receiving scenarios:

[0314] (1) The radio frequency circuit is in the transmitting state.

[0315] Alternatively, when the RF circuit is in receiving mode, the RF chip 201 receives the second RF signal, and the second switching device 2027 bypasses the second LNA 2024 to enable the sixth receiving channel between the RF chip 201 and the second port 2022 of the RF front-end module 202. Thus, the first RF signal entering the RF front-end module 202 through the second port 2022 is transmitted through the sixth receiving channel and then enters the RF chip 201 through the receiving port 2012.

[0316] In one possible embodiment of this application, as shown in Figures 12-14, the first control terminal of the third sub-switch circuit 9011 and the first control terminal of the fourth sub-switch circuit 9012 can receive a first control signal. The control terminal of the third LNA 913 can be used to receive a third control signal.

[0317] In the embodiments of this application, the first control signal and the third control signal can be the same control signal or different control signals, and the embodiments of this application do not limit this.

[0318] The third control signal can be either level signal 11 or level signal 12. Level signal 11 is a high-level signal, and level signal 12 is a low-level signal. Level signal 11 is used to trigger the third LNA 913 to turn off. Level signal 12 is used to trigger the third LNA 913 to turn on. The first control signal can be either level signal 13 or level signal 14. Level signal 13 is a high-level signal, and level signal 14 is a low-level signal. Level signal 13 is used to trigger the second terminal of the third sub-switch circuit 9011 or the fourth sub-switch circuit 9012 to connect to the first terminal. Level signal 14 is used to trigger the second terminal of the third sub-switch circuit 9011 or the fourth sub-switch circuit 9012 to connect to the third terminal. Alternatively, level signal 14 can be used to trigger the second terminal of the third sub-switch circuit 9011 or the fourth sub-switch circuit 9012 to connect to the first terminal, and level signal 13 can be used to trigger the second terminal of the third sub-switch circuit 9011 or the fourth sub-switch circuit 9012 to connect to the third terminal.

[0319] When the RF circuit is in transmit / receive mode, the third control signal, which can be a level signal 11, can trigger the third LNA 9013 to turn off. The third sub-switch circuit 9011 is used to connect the second terminal 90111 and the third terminal 90113 of the third sub-switch circuit 9011 based on the level signal 14. The fourth sub-switch circuit 9012 is used to connect the second terminal 90121 and the third terminal 90122 of the fourth sub-switch circuit based on the level signal 14. The third terminal 90122 of the fourth sub-switch circuit is connected to the third terminal 90113 of the third sub-switch circuit 9011, thus enabling the conduction of the fourth receiving channel or the first transmitting channel on the second circuit board 300.

[0320] When the RF circuit is in receiving mode, the third control signal can be a low-level signal, i.e., level signal 12, used to trigger the third LNA 9013 to turn on. The third sub-switch circuit 9011 is used to connect its second terminal 90111 and its first terminal 90112 based on level signal 14. The fourth sub-switch circuit 9012 is used to connect its second terminal 90121 and its first terminal 90122 based on level signal 14, thereby enabling the third receiving channel to be activated. This achieves signal gain.

[0321] In another possible implementation of this application, in order to achieve reception bypass when the radio frequency circuit is in the transmitting state or in the receiving state, the radio frequency circuit may also output a level signal 11 as a third control signal and output a level signal 14 as a first control signal to the first control terminal of the third sub-switch circuit 9011 and the first control terminal of the fourth sub-switch circuit 9012.

[0322] In order to achieve receiving gain, the RF circuit can also output level signal 12 as a third control signal and output level signal 13 as a first control signal to the first control terminal of the third sub-switch circuit 9011 and the first control terminal of the fourth sub-switch circuit 9012 when the RF circuit is in the receiving state.

[0323] Specifically, the first control signal and the third control signal can be provided by the radio frequency chip 201.

[0324] Specifically, the first control terminal of the third sub-switch circuit 9011 and the first control terminal of the fourth sub-switch circuit 9012 are connected to one output interface of the RF chip 201, and the other output interface of the RF chip 201 is connected to the third LNA 9013.

[0325] In this embodiment, the first and third control signals can be provided by the RF chip 201 or a processor within the RF circuit. For example, the RF chip 201 has GPIO8 and GPIO9, where GPIO8 is used to output the first control signal and GPIO9 is used to output the third control signal. Specifically, GPIO8 is connected to the first control terminal of the third sub-switch circuit 9011 and the first control terminal of the fourth sub-switch circuit 9012. GPIO9 is connected to the control terminal of the third LNA 913.

[0326] Alternatively, the first control signal and the third control signal in this embodiment can be provided by logic circuitry. Optionally, the logic circuitry can perform logical operations on the multiple level signals provided by the RF chip 201 to the RF front-end module 202 through GPIO0 and GPIO3 to obtain the signal; this embodiment does not limit this approach.

[0327] In the RF circuit structure shown in Figures 12-14, the first circuit board 200 can be arranged on the side of the terminal device away from the antenna module 400, and the second circuit board 300 can be arranged on the side of the terminal device closer to the antenna module 400. For example, the second circuit board 300 and the antenna module 400 can be connected by an FPC, a metal spring, or a cable.

[0328] In one possible embodiment of this application, as shown in Figures 12 to 14, the inter-board connection between the first circuit board 200 and the second circuit board 300 includes at least one signal transmission line (e.g., for transmitting Wi-Fi TRX signals), a power transmission line, and a logic control signal transmission line.

[0329] The power transmission line is used to provide power to the first switching circuit 301 and the first gain unit 302. For example, one end of the power transmission line is connected to the power supply, and the other end is connected to the power supply terminals of the first sub-switching circuit 9011, the second sub-switching circuit 9012, and the third LNA 9013, respectively.

[0330] The aforementioned signal transmission line is used to transmit the second radio frequency signal emitted by the radio frequency chip 201 and to receive the first radio frequency signal received by the antenna module. One end of the signal transmission line is connected to the second port 2022 of the radio frequency front-end module 202, and the other end is connected to the second terminal 90111 of the first sub-switch circuit 9011 on the second circuit board 300. Alternatively, the other end of the signal transmission line is connected to a signal transmission port on the second circuit board. This signal transmission port is connected to a third receiving channel, a fourth receiving channel, or a first transmitting channel.

[0331] The aforementioned signal transmission line can be a single line. Alternatively, it can include two lines (e.g., signal transmission line 1 and signal transmission line 2). One signal transmission line 1 transmits the second radio frequency signal emitted by the radio frequency chip 201 to the second circuit board 300. The other signal transmission line 2 transmits the first radio frequency signal from the second circuit board 300 to the first circuit board 200. If the aforementioned signal transmission line can include two lines, one end of signal transmission line 1 is connected to the second port 2022 of the radio frequency front-end module 202. The other end of signal transmission line 1 is connected to signal transmission port 1 on the second circuit board. Signal transmission port 1 is connected to the first transmitting channel. One end of signal transmission line 2 is connected to the second port 2022 of the radio frequency front-end module 202, and the other end of signal transmission line 2 is connected to signal transmission port 2 on the second circuit board. Signal transmission port 2 is connected to the third or fourth receiving channel.

[0332] The logic control signal transmission line provides level signals to the first control terminal of the first sub-switch circuit 9011, the first control terminal of the second sub-switch circuit 9012, and the control terminal of the third LNA 9013. One end of the logic control signal transmission line can be connected to the output port of the logic circuit or the RF chip 201. The other end of the logic control signal transmission line can be connected to the first control terminal of the first sub-switch circuit 9011, the first control terminal of the second sub-switch circuit 9012, and the control terminal of the third LNA 9013. The logic control signal transmission line may include one or more lines; this embodiment does not limit this.

[0333] For example, the connection between the first circuit board 200 and the second circuit board 300 can be achieved using an FPC. Alternatively, the connection between the first circuit board 200 and the second circuit board 300 can be entirely achieved using cable lines. Or, the connection between the first circuit board 200 and the second circuit board 300 can be achieved using both FPC and cable lines.

[0334] In one embodiment of this application, the first circuit board 200 and the second circuit board 300 can be connected via an FPC and / or a cable. For example, taking the connection between the first circuit board 200 and the second circuit board 300 via an FPC and a cable as an example, the cable can serve as a signal transmission line between the first circuit board 200 and the second circuit board 300. One end of the signal transmission line is connected to the second port 2022, and the other end is connected to the second terminal 20252 of the third switching circuit 2025 or the second terminal 2022 of the RF front-end module 202. This signal transmission line is used to transmit a first RF signal and / or a second RF signal. Power lines and logic control signal transmission lines can be arranged on the FPC. The logic control signal transmission lines are used to transmit level signals for controlling the first switching circuit 301 and the first gain unit 302. The power line provides power to the first switching circuit 301 and the first gain unit 302. One end of the power line is connected to a power source, and the other end is connected to the power supply terminal of the first switching circuit 301 (e.g., the third sub-switching circuit 9011 and the fourth sub-switching circuit 9012) and the power supply terminal of the first gain unit 302. There may be one or more logic control signal transmission lines. One end of each logic control signal transmission line is connected to the first control terminal of the third sub-switching circuit 9011, the first control terminal of the fourth sub-switching circuit 9012, or the control terminal of the first gain unit 302. The other end of the logic control signal transmission line is connected to the circuit providing the first or third control signal. For example, the other end of the logic control signal transmission line may be connected to the output port of the logic circuit or the RF chip 201 (e.g., GPIO8 or GPIO9) or the processor in the RF circuit. This embodiment does not limit this.

[0335] Alternatively, taking the connection between the first circuit board 200 and the second circuit board 300 via an FPC as an example, the first circuit board 200 and the second circuit board 300 can be connected via an FPC, on which the aforementioned signal transmission lines, power lines and logic control signal transmission lines are arranged.

[0336] Alternatively, taking the connection between the first circuit board 200 and the second circuit board 300 via a cable line as an example, the first circuit board 200 and the second circuit board 300 may include multiple cable lines. For example, the cable lines may include signal transmission lines, power lines for the first switching circuit 301, power lines for the first gain unit 302, and transmission lines for logic control signals, etc.

[0337] In the RF circuit structures shown in Figures 12-14, the RF front-end module 202 of the first circuit board 200 and the first switching circuit 301 of the second circuit board 300 can be combined to form three functional channels: TX, RX GAIN, and RX Bypass. The two gain units located on the first circuit board 200 and the second circuit board 300, namely the third LNA9013 and the second LNA2024, can be combined to form various receive gain modes, including: third LNA9013 Gain (i.e., using the third LNA9013 to achieve receive signal gain) + second LNA2024 Gain (i.e., using the second LNA2024 to achieve receive signal gain), third LNA9013 Gain + second LNA2024 Bypass (i.e., bypassing the second LNA2024), third LNA9013 Bypass + second LNA2024 Gain, or third LNA9013 Bypass + second LNA2024 Bypass, etc.

[0338] The working process of the radio frequency circuit in the embodiments of this application in the receiving and transmitting scenarios is now described with reference to the structure of the radio frequency circuit shown in Figures 12 to 14.

[0339] (1) The radio frequency circuit is in the transmitting state.

[0340] For example, as shown in Figure 15, the RF chip 201 is used to transmit a second RF signal, and the third switching circuit 2025 is used to connect the second transmission channel between the transmit port 2011 of the RF chip 201 and the second port 2022 of the RF front-end module 202. The first power amplifier 2023 is located on the second transmission channel. Thus, the second RF signal transmitted by the RF chip 201 through the transmit port 2011 is transmitted to the first power amplifier 2023 via the second transmission channel. After the first power amplifier 2023 amplifies the second RF signal, the amplified second RF signal enters the second circuit board 300 through the second port 2022 of the RF front-end module 202.

[0341] Because the second terminal 90111 of the third sub-switch circuit 9011 on the second circuit board 300 is connected to the third terminal 90113 of the third sub-switch circuit 9011, and the second terminal 90121 of the fourth sub-switch circuit 9012 is connected to the third terminal 90123 of the fourth sub-switch circuit 9012, and the third terminal 90113 of the third sub-switch circuit 9011 is connected to the third terminal 90123 of the fourth sub-switch circuit 9012, the first transmission channel on the second circuit board 300 is turned on, and the amplified second radio frequency signal is transmitted to the antenna module 400 through the first transmission channel. For example, it can be filtered by the filter 500 and then sent to the antenna module 400 for transmission by the antenna module 400.

[0342] In the scenario shown in Figure 15, it can be assumed that the transmission channel between the transmitter port 2011 of the RF chip 201 and the antenna module 400 includes the aforementioned second transmission channel and the first transmission channel. The first and second transmission channels are connected by a signal transmission line between the second circuit board 300 and the first circuit board 200.

[0343] The following describes how the following functions are achieved when the RF circuit is in receive mode:

[0344] (2) Two-level RX Bypass function

[0345] When the RF circuit is in receiving mode, the RF chip 201 is used to receive RF signals.

[0346] Specifically, as shown in Figure 16, the second terminal 90111 of the third sub-switch circuit 9011 is connected to the third terminal 90113 of the third sub-switch circuit 9011, and the second terminal 90121 of the fourth sub-switch circuit 9012 is connected to the third terminal 90123 of the fourth sub-switch circuit 9012. Since the third terminal 90113 of the third sub-switch circuit 9011 is connected to the third terminal 90123 of the fourth sub-switch circuit 9012, the third LNA 9013 is bypassed, forming a fourth receiving channel on the second circuit board 300 that does not pass through the third LNA 9013. That is, the fourth receiving channel is a channel that bypasses the third LNA 9013 and connects the RF front-end module 202 and the antenna module 400. In this way, the first RF signal received by the antenna module 400 is processed by the filter 500, transmitted through the fourth receiving channel, and enters the RF front-end module 202 through the second port 2022 of the RF front-end module 202.

[0347] Within the RF front-end module 202, a third switching circuit 2025 is used to connect the sixth receiving channel between the RF chip 201 and the second port 2022 of the RF front-end module 202. That is, the third switching circuit 2025 within the RF front-end module 202 is used to bypass the second LNA 2024, or the second switching device 2027 and / or switching device 2 are closed to bypass the second LNA 2024. Thus, the first RF signal entering the RF front-end module 202 is transmitted through the sixth receiving channel and enters the RF chip 201 through the receiving port 2012 of the RF chip 201.

[0348] In this scheme, the third LNA9013 on the second circuit board 300 is bypassed, and the second LNA2024 on the first circuit board 200 is bypassed. Since the first radio frequency signal received by the antenna module 400 is not amplified by the third LNA9013 and the second LNA2024, the radio frequency circuit can realize a two-stage RX Bypass function, namely the third LNA9013 Bypass + second LNA2024 Bypass circuit scheme.

[0349] In the scenario shown in Figure 16, it can be assumed that the receiving channel between the receiving port 2012 of the RF chip 201 and the antenna module 400 includes the aforementioned fourth receiving channel and sixth receiving channel. The fourth and sixth receiving channels are connected by a signal transmission line between the second circuit board 300 and the first circuit board 200.

[0350] The first radio frequency signal does not require gain processing after passing through the fourth and sixth receiving channels.

[0351] (3) Third LNA9013 Gain + Second LNA2024 Bypass function.

[0352] When the RF circuit is in receiving mode, as shown in Figure 17, the second terminal 90111 of the third sub-switch circuit 9011 is connected to the first terminal 90112 of the third sub-switch circuit 9011. The second terminal 90121 of the fourth sub-switch circuit 9011 is connected to the first terminal 90122 of the fourth sub-switch circuit 9012. The second terminal 90112 of the third sub-switch circuit 9011 is connected to the output terminal of the third LNA 9013, and the input terminal of the third LNA 9013 is connected to the first terminal 90122 of the fourth sub-switch circuit 9012. The third LNA 9013 is turned on, so the third receiving channel on the second circuit board 300 is turned on by the third sub-switch circuit 9011 and the fourth sub-switch circuit 9012. The first RF signal received by the antenna module 400 is processed by the filter 500 and then transmitted through the third receiving channel. The first RF signal is amplified by the third LNA 9013 in the third receiving channel and then enters the RF front-end module 202 through the second port 2022 of the RF front-end module 202.

[0353] Within the RF front-end module 202, a third switching circuit 2025 is used to connect the sixth receiving channel between the RF chip 201 and the second port 2022 of the RF front-end module 202. That is, the third switching circuit 2025 within the RF front-end module 202 is used to bypass the second LNA 2024, or the second switching device 2027 and / or switching device 2 are closed to bypass the second LNA 2024. Thus, the first RF signal entering the RF front-end module 202 is transmitted through the sixth receiving channel and enters the RF chip 201 through the receiving port 2012 of the RF chip 201.

[0354] In this embodiment, the third sub-switch circuit 9011 and the fourth sub-switch circuit 9012 on the second circuit board 300 jointly enable the conduction of the third receiving channel within the second circuit board 300. The second switching device 2027 on the first circuit board 200 is disconnected, and the second LNA 2024 on the first circuit board 200 achieves the gain of the first radio frequency signal, thus realizing the function of third LNA 9013 Bypass + second LNA 2024 Gain.

[0355] It is understood that in the circuit shown in Figure 17, the receiving channel between the receiving port 2012 of the RF chip 201 and the antenna module 400 includes the third receiving channel located on the second circuit board 300 and the sixth receiving channel located on the first circuit board 200. The sixth receiving channel and the third receiving channel are connected by a signal transmission line between the second circuit board 300 and the first circuit board 200.

[0356] (4) Second LNA 2024 Gain + Third LNA 9013 Bypass Function

[0357] When the RF circuit is in receiving mode, as shown in Figure 18, the second terminal 90111 of the third sub-switch circuit 9011 is connected to the third terminal 90113 of the third sub-switch circuit 9011. The second terminal 90121 of the fourth sub-switch circuit 9012 is connected to the third terminal 90123 of the fourth sub-switch circuit 9012. Since the third terminal 90113 of the third sub-switch circuit 9011 is connected to the third terminal 90123 of the fourth sub-switch circuit 9012, the third LNA 9013 is bypassed, forming a fourth receiving channel on the second circuit board 300 that does not pass through the third LNA 9013. That is, the fourth receiving channel is a channel that bypasses the third LNA 9013 and connects the RF front-end module 202 and the antenna module 400. Within the second circuit board 300, the first RF signal received by the antenna module 400 is processed by the filter 500 and then transmitted through the fourth receiving channel. The first RF signal enters the RF front-end module 202 through the second port 2022 of the RF front-end module 202.

[0358] If the switching device 2 in the RF front-end module 202 is closed and the second switching device 2027 is open, or if the second switching device 2027 is open and the second terminal 20252 of the third switching circuit 2025 is connected to the third terminal 20253 of the third switching circuit 2025, then the fifth receiving channel between the second port 2022 in the RF front-end module 202 and the receiving port 2012 of the RF chip 201 is connected. Alternatively, the receiving channel in the RF front-end module 202 can be considered as the fifth receiving channel. The second LNA 2024 is located on the fifth receiving channel, so the first RF signal entering the RF front-end module 202 (i.e., the first RF signal that has been amplified) is transmitted to the RF chip 201 after being amplified again by the second LNA 2024.

[0359] In this embodiment, the third sub-switch circuit 9011 and the fourth sub-switch circuit 9012 on the second circuit board 300 jointly bypass the third LNA 9013, so that the receiving channel within the second circuit board 300 becomes the fourth receiving channel, i.e., the fourth receiving channel is turned on. The second switching device 2027 on the first circuit board 200 is turned off, and the second LNA 2024 on the first circuit board 200 gains the first RF signal entering the RF front-end module 202, thus realizing the function of third LNA 9013 Bypass + second LNA 2024 Gain.

[0360] It is understood that in the circuit shown in Figure 18, the receiving channel between the receiving port 2012 of the RF chip 201 and the antenna module 400 includes the fourth receiving channel located on the second circuit board 300 and the fifth receiving channel located on the first circuit board 200. The fifth receiving channel and the fourth receiving channel are connected by a signal transmission line between the second circuit board 300 and the first circuit board 200.

[0361] (5) Two-stage gain function

[0362] When the RF circuit is in receiving mode, as shown in Figure 19, the second terminal 90111 of the third sub-switch circuit 9011 is connected to the first terminal 90112 of the third sub-switch circuit 9011. The second terminal 90121 of the fourth sub-switch circuit 9011 is connected to the first terminal 90122 of the fourth sub-switch circuit 9012. The second terminal 90112 of the third sub-switch circuit 9011 is connected to the output terminal of the third LNA 9013, and the input terminal of the third LNA 9013 is connected to the first terminal 90122 of the fourth sub-switch circuit 9012. The third LNA 9013 is turned on. Therefore, the third receiving channel on the second circuit board 300 is turned on by the third sub-switch circuit 9011 and the fourth sub-switch circuit 9012. The first RF signal received by the antenna module 400 is processed by the filter 500 and transmitted through the third receiving channel, and enters the RF front-end module 202 through the second port 2022 of the RF front-end module 202.

[0363] If the switching device 2 in the RF front-end module 202 is closed and the second switching device 2027 is open, or if the second switching device 2027 is open and the second terminal 20252 of the third switching circuit 2025 is connected to the third terminal 20253 of the third switching circuit 2025, then the fifth receiving channel between the second port 2022 in the RF front-end module 202 and the receiving port 2012 of the RF chip 201 is connected. Alternatively, the receiving channel in the RF front-end module 202 can be considered as the fifth receiving channel. The second LNA 2024 is located on the fifth receiving channel, so the first RF signal entering the RF front-end module 202 (i.e., the first RF signal that has been amplified) is transmitted to the RF chip 201 after being amplified again by the second LNA 2024.

[0364] In this scheme, the third sub-switch circuit 9011 and the fourth sub-switch circuit 9012 on the second circuit board 300 jointly enable the conduction of the third receiving channel to amplify the first RF signal using the third LNA 9013. On the first circuit board 200, the second LNA 2024 can be used to further amplify the first RF signal, which has already been amplified by the third LNA 9013, entering the RF front-end module 202. Therefore, it is possible to amplify the first RF signal using LNAs on both PCBs, achieving a two-stage RX Gain function: second LNA 2024 Gain + third LNA 9013 Gain.

[0365] It is understood that in the circuit shown in Figure 19, the receiving channel between the receiving port 2012 of the RF chip 201 and the antenna module 400 includes the third receiving channel located on the second circuit board 300 and the fifth receiving channel located on the first circuit board 200. The fifth receiving channel and the third receiving channel are connected by a signal transmission line between the second circuit board 300 and the first circuit board 200.

[0366] In the embodiments shown in Figures 3 to 19 of this application, a first LNA and a first switching circuit are added to a small PCB board (i.e., the second circuit board 300) near the antenna module. The small PCB board and the main PCB board (i.e., the first circuit board 200) are connected via a long cable or FPC to improve the performance of the entire transceiver system. By using the first LNA as a pre-amplifier, the NF of the receiving link can be reduced, making the line loss almost equal to the line loss generated on the second circuit board 300. This improves the receiving sensitivity. By increasing the PA's transmit power, the loss between the boards is compensated, and the overall transmission performance is maintained. Specifically, in this application embodiment, the NF of the receiving link can be determined by the following formula:

[0367] Among them, F 小板 This indicates the loss on the second circuit board 300. F 连接 This indicates the connection loss between the second circuit board 300 and the first circuit board 200. (F) 主板 This indicates the loss on the first circuit board 200. G 小板(LNA) This indicates the gain of the first LNA. The G connection indicates the connection loss between the second circuit board 300 and the antenna module 400. F RFIC This indicates the loss of the radio frequency chip. G 主板 This indicates the gain of the LNA on the first circuit board 200.

[0368] In another embodiment of this application, this application provides a terminal device, which may include the radio frequency circuits shown in Figures 12 to 19.

[0369] Optionally, the terminal device may also include an antenna module 400. For example, the first circuit board 200 is located on the side of the terminal device away from the antenna module 400. The second circuit board 300 is located on the side of the terminal device closer to the antenna module.

[0370] Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0371] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0372] In the several embodiments provided in this application, it should be understood that the disclosed systems and devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the direct coupling or communication connection between devices or units may be electrical or other forms.

[0373] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A radio frequency circuit, characterized in that, The circuit includes: a first circuit board and a second circuit board, the first circuit board and the second circuit board being connected, and the second circuit board being connected to the antenna module; The first circuit board includes a radio frequency chip; The second circuit board includes: a first switching circuit and a first gain unit; The first switching circuit is at least used to enable the first radio frequency signal to be transmitted on the second circuit board through the first gain unit, and the first gain unit is used to perform gain processing on the first radio frequency signal; the first radio frequency signal is the radio frequency signal received by the antenna module; The radio frequency chip is used to receive the first radio frequency signal after gain.

2. The radio frequency circuit according to claim 1, characterized in that, The first gain unit includes a first low-noise amplifier (LNA).

3. The radio frequency circuit according to claim 1 or 2, characterized in that, The first switching circuit is also used to enable the first radio frequency signal to be transmitted on the second circuit board without passing through the first gain unit; the radio frequency chip is used to receive the first radio frequency signal without the gain unit.

4. The radio frequency circuit according to any one of claims 1 to 3, characterized in that, The first circuit board also includes a radio frequency front-end module, and the radio frequency chip includes a transmit port; The transmitter port of the radio frequency chip is connected to the first port of the radio frequency front-end module; The second port of the radio frequency front-end module is connected to the antenna module through the first transmission channel on the second circuit board. The first transmission channel is used to transmit the second radio frequency signal transmitted by the radio frequency chip through the transmission port.

5. The radio frequency circuit according to claim 4, characterized in that, The first switching circuit is also used to disconnect the connection between the second port of the RF front-end module and the antenna module, or to connect the second port of the RF front-end module and the antenna module.

6. The radio frequency circuit according to any one of claims 1 to 3, characterized in that, The first circuit board also includes a radio frequency front-end module, the transmit port of the radio frequency chip is connected to the radio frequency front-end module, and the radio frequency front-end module is also connected to the antenna module.

7. The radio frequency circuit according to any one of claims 1 to 6, characterized in that, The receiving port of the radio frequency chip is connected to the first switching circuit, and the second circuit board includes a first receiving channel and a second receiving channel. The first switching circuit is specifically used to switch between the first receiving channel and the second receiving channel. The first receiving channel is the channel between the antenna module and the receiving port of the RF chip that passes through the first gain unit, and the second receiving channel is the channel between the antenna module and the RF chip that does not pass through the first gain unit.

8. The radio frequency circuit according to claim 7, characterized in that, The first switching circuit includes a first sub-switching circuit and a second sub-switching circuit; The second terminal of the first sub-switch circuit is connected to the receiving port of the radio frequency chip; The first terminal of the first sub-switch circuit is connected to the output terminal of the first gain unit, and the third terminal of the first sub-switch circuit is connected to the fourth terminal of the second sub-switch circuit. The input terminal of the first gain unit is connected to the third terminal of the second sub-switch circuit, and the first terminal of the second sub-switch circuit is connected to the RF front-end module. The second terminal of the second sub-switch circuit is connected to the antenna module.

9. The radio frequency circuit according to any one of claims 1 to 8, characterized in that, The radio frequency circuit also includes: A logic circuit, wherein the first output terminal of the logic circuit is connected to the second control terminal of the first switching circuit, and the second output terminal of the logic circuit is connected to the first control terminal of the first switching circuit and the control terminal of the first gain unit. The logic circuit is used to output a first control signal and a third control signal to the first switching circuit and the first gain unit respectively through the second output terminal, and to output a second control signal to the first switching circuit through the first output terminal; the first control signal and the second control signal are used to trigger the first switching circuit to switch the channel between the antenna module and the receiving port of the radio frequency chip to the first receiving channel or the second receiving channel, and the third control signal is used to trigger the first gain unit to turn on or off.

10. The radio frequency circuit according to claim 9, characterized in that, The logic circuit is connected to the radio frequency chip, and the radio frequency chip is also connected to the radio frequency front-end module; The logic circuit is specifically used to convert multiple level signals provided by the RF chip to the RF front-end module into the first control signal, the second control signal, and the third control signal.

11. The radio frequency circuit according to claim 9 or 10, characterized in that, The logic circuit includes: First OR gate, second OR gate, and first NOT gate The first input terminal and the second input terminal of the first OR gate device are respectively connected to the first control pin and the third control pin of the RF front-end module; The input terminal of the first NOT gate is connected to the second control pin of the RF front-end module, and the output terminals of the first OR gate and the first NOT gate are respectively connected to the two input terminals of the second OR gate; the first control pin, the second control pin, and the third control pin are respectively used to receive level signals; The output terminal of the second OR gate device is connected as the second output terminal of the logic circuit to the first control terminal of the first switching circuit and the control terminal of the first gain unit. The output terminal of the first OR gate device is connected to the second control terminal of the first switching circuit as the first output terminal of the logic circuit.

12. The radio frequency circuit according to claim 9 or 10, characterized in that, The logic circuit includes: The third OR gate, the fourth OR gate, the fifth OR gate, and the second NOT gate. The first and second input terminals of the third OR gate device are respectively connected to the first and third control pins of the RF front-end module. The input terminal of the second NOT gate is used to connect to the second control pin of the RF front-end module; the first control pin, the second control pin, and the third control pin are respectively used to receive level signals; The output terminal of the third OR gate and the output terminal of the second NOT gate are respectively used to connect to the two input terminals of the fourth OR gate. The output terminal of the fourth OR gate device serves as the second output terminal of the logic circuit, connecting to the first control terminal of the first switching circuit and the control terminal of the first gain unit. The first input terminal of the fifth OR gate is connected to the output terminal of the second NOT gate, the second input terminal of the fifth OR gate is connected to the first input terminal of the third OR gate, and the output terminal of the fifth OR gate is connected to the second control terminal of the first switching circuit as the first output terminal of the logic circuit.

13. The radio frequency circuit according to any one of claims 1 to 8, characterized in that, The radio frequency chip is also connected to the first switching circuit and the first gain unit. The radio frequency chip is used to output a first control signal to the first control terminal of the first switching circuit and a third control signal to the control terminal of the first gain unit, and to output a second control signal to the second control terminal of the first switching circuit; the first control signal and the second control signal are used to trigger the first switching circuit to switch the channel between the antenna module and the receiving port of the radio frequency chip to a first receiving channel or a second receiving channel, and the third control signal triggers the first gain unit to turn on or off.

14. The radio frequency circuit according to any one of claims 1 to 6, characterized in that, The radio frequency circuit further includes a second switching circuit, wherein the receiving port of the radio frequency chip is connected to the first switching circuit through the second switching circuit, and the second circuit board includes a first receiving channel and a second receiving channel, wherein the first switching circuit is used to switch between the first receiving channel and the second receiving channel. The first receiving channel is the channel between the antenna module and the receiving port of the RF chip that passes through the first gain unit, and the second receiving channel is the channel between the antenna module and the RF chip that does not pass through the first gain unit. When the radio frequency circuit is in the receiving state, the second switching circuit is used to connect the first communication port of the first switching circuit and the receiving port of the radio frequency chip, wherein the first communication port is connected to the first receiving channel or the second receiving channel.

15. The radio frequency circuit according to claim 14, characterized in that, The first terminal of the second switching circuit is connected to the second port of the RF front-end module. When the radio frequency circuit is in the transmitting state, the second switching circuit is used to connect the second port of the radio frequency front-end module and the first communication port of the first switching circuit, and the radio frequency front-end module is deployed on the first circuit board.

16. The radio frequency circuit according to claim 15, characterized in that, The second switching circuit is connected to the radio frequency chip; When the radio frequency circuit is in the transmitting state, the radio frequency chip is used to output a fourth control signal to the second switching circuit. The fourth control signal is used to control the second switching circuit to connect the second port of the radio frequency front-end module and the first communication port of the first switching circuit. The first communication port is connected to the first transmitting channel on the first circuit board. When the radio frequency circuit is in the receiving state, the radio frequency chip is used to output a fifth control signal to the second switching circuit. The fifth control signal is used to control the second switching circuit to connect the first communication port of the first switching circuit and the receiving port of the radio frequency chip. The first communication port is connected to the first receiving channel or the second receiving channel.

17. The radio frequency circuit according to any one of claims 1 to 6, characterized in that, The first circuit board further includes an RF front-end module, the RF chip has a receiving port, the receiving port of the RF chip is connected to the third port of the RF front-end module; the second port of the RF front-end module is connected to the first switching circuit. The first switching circuit is used to switch between the third receiving channel and the fourth receiving channel on the second circuit board; the third receiving channel is the channel between the antenna module and the second port of the RF front-end module through the first gain unit, and the fourth receiving channel is the channel between the antenna module and the second port of the RF front-end module without passing through the first gain unit.

18. The radio frequency circuit according to claim 17, characterized in that, The radio frequency front-end module is used to switch between the fifth and sixth receiving channels within the radio frequency front-end module. The fifth receiving channel is the channel between the receiving port of the RF chip and the second port of the RF front-end module; The fifth receiving channel is used to transmit the first radio frequency signal to the radio frequency chip after amplification. The sixth receiving channel is used to connect the receiving port of the RF chip to the second port of the RF front-end module; the sixth receiving channel is used to prevent the first RF signal from undergoing gain processing.

19. The radio frequency circuit according to claim 18, characterized in that, The radio frequency front-end module includes: a second power amplifier, a second gain unit, and a third switching circuit; The second gain unit is located on the fifth receiving channel. The second power amplifier is located on the second transmission channel within the RF front-end module. The input terminal of the second power amplifier is connected to the transmission port of the RF chip, and the output terminal of the second power amplifier is connected to the first terminal of the third switching circuit. The second terminal of the third switching circuit is connected to the second circuit board. The third terminal of the third switching circuit is connected to the input terminal of the second gain unit, and the output terminal of the second gain unit is connected to the receiving port of the RF chip; the third switching circuit is used to switch between the second transmitting channel, the fifth receiving channel, and the sixth receiving channel.

20. The radio frequency circuit according to any one of claims 14 to 18, characterized in that, The first switching circuit includes: a third sub-switching circuit and a fourth sub-switching circuit, wherein, The second terminal of the third sub-switch circuit serves as the first communication port of the first switch circuit. The third terminal of the third sub-switch circuit is connected to the third terminal of the fourth sub-switch circuit. The first terminal of the third sub-switch circuit is connected to the output terminal of the first gain unit. The input terminal of the first gain unit is connected to the first terminal of the fourth sub-switch circuit. The second terminal of the fourth sub-switch circuit serves as the third communication port of the first switch circuit and is connected to the antenna module.

21. The radio frequency circuit according to any one of claims 14 to 20, characterized in that, The first switching circuit and the first gain unit are also connected to the radio frequency chip; The radio frequency chip is used to output a fifth control signal to the first control terminal of the first switching circuit and a sixth control signal to the control terminal of the first gain unit. The fifth control signal is used to control the first gain unit to turn on or off, and the sixth control signal is used to control the first switching circuit to switch between the second receiving channel and the first receiving channel.

22. The radio frequency circuit according to any one of claims 1 to 21, characterized in that, The connection between the second circuit board and the first circuit board includes: the third terminal of the second switching circuit is connected to the first communication port of the first switching circuit via a flexible printed circuit board (FPC) and / or a cable line.

23. The radio frequency circuit according to any one of claims 1 to 22, characterized in that, The radio frequency circuit further includes a filter, which is connected in series between the second circuit board and the antenna module.

24. A terminal device, characterized in that, Includes the radio frequency circuit as described in any one of claims 1 to 23.

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