Capacitance compensation circuit, switch, radio frequency circuit and communication equipment

Abstract

The utility model provides a capacitance compensation circuit, a switch, a radio frequency circuit and a communication device, and relates to the technical field of antennas, and the method is used for realizing the more balanced voltage swing of each stage of switching circuit on the basis of realizing the lower total capacitance value. The circuit is applied to a radio frequency switch, the radio frequency switch is provided with an input end and an output end, the capacitance compensation circuit comprises N cascaded switch circuits, the output end of the upper-stage switch circuit in the N switch circuits is connected with the input end of the lower-stage switch circuit, and the output end of the lower-stage switch circuit in the N switch circuits is connected with the input end of the lower-stage switch circuit. The input end of the first stage of switch circuit in the N cascaded switch circuits is connected with the input end of the radio frequency switch, the output end of the last stage of switch circuit in the N cascaded switch circuits is connected with the output end of the radio frequency switch, and N is greater than or equal to 2; and at least one compensation capacitor, wherein any compensation capacitor is bridged between the at least two stages of switching circuits.

Description

Technical Field

[0001] This application relates to the field of antenna technology, and in particular to a capacitor compensation circuit, a switch, a radio frequency circuit, and a communication device. Background Technology

[0002] Radio frequency switches can be used in transceiver communication scenarios as transmit (TX) switching switches and in antennas as antenna switches.

[0003] Typically, RF switches are composed of cascaded multi-stage switching transistor circuits. When an RF switch is used as a transmit (TX) switching switch or an antenna switch, if the RF switch is open, in a transmission scenario, the RF signal transmitted from the RF chip is amplified by the power amplifier and can be transmitted from the transmit port to the antenna. However, during signal transmission, because the RF switch is grounded or grounded through the load and then disconnected, the two ends of the RF switch will experience a relatively large voltage difference from the RF front end. Moreover, the existence of the RF switch die parasitic effect will cause the voltage swing of each switching transistor to be unequal when the RF switch includes multiple switching transistors, resulting in poor voltage withstand capability of the switch, which can easily lead to the die breakdown of the previous stage switching transistor, and eventually the entire switch burns out and fails.

[0004] Therefore, how to solve the problem of uneven voltage swing distribution at each stage of RF switch in high-voltage scenarios is an urgent technical problem to be solved. Summary of the Invention

[0005] This application provides a capacitor compensation circuit, a switch, a radio frequency circuit, and a communication device. The method is used to achieve a more balanced voltage swing in each stage of the switching circuit while achieving a lower total capacitance value.

[0006] In a first aspect, embodiments of this application provide a capacitance compensation circuit applied in a switch (such as a radio frequency switch). The radio frequency switch has an input terminal and an output terminal. The capacitance compensation circuit includes: N cascaded switch circuits, wherein the output terminal of the previous stage switch circuit in the N cascaded switch circuits is connected to the input terminal of the next stage switch circuit, the input terminal of the first stage switch circuit in the N cascaded switch circuits is connected to the input terminal of the radio frequency switch, and the output terminal of the last stage switch circuit in the N cascaded switch circuits is connected to the output terminal of the radio frequency switch, wherein N is greater than or equal to 2.

[0007] At least one compensation capacitor, any one of which is connected across at least two stages of switching circuitry.

[0008] This application provides a capacitor compensation circuit. This solution uses a compensation capacitor connected in series between at least two stages of a multi-stage switching circuit. Specifically, any compensation capacitor is connected across at least two stages of the switching circuit. This allows for capacitor compensation for each stage of the at least two-stage switching circuit, resulting in a more balanced voltage swing for each stage. Furthermore, this method of connecting compensation capacitors between at least two stages of the switching circuit reduces the number of compensation capacitors, lowering the total capacitance value of the capacitor compensation circuit in both on and off states. A lower total capacitance value allows for stronger isolation of the RF switch against RF signals, and also addresses the problem of excessive degradation in the total resistance R_ON in the on state and the total capacitance C_OFF in the off state.

[0009] In one possible implementation of this application, the first terminal of any compensation capacitor is connected to the input terminal of the i-th stage switching circuit, the second terminal of any compensation capacitor is connected to the output terminal of the j-th stage switching circuit, and the first terminals of different compensation capacitors are connected to the input terminals of different switching circuits. i is an integer greater than or equal to 1 and less than or equal to N-1, and j is greater than or equal to i+1 and less than or equal to N. This scheme can achieve source and drain compensation for each stage of the switching circuit by connecting a compensation capacitor across the input terminal of one stage switching circuit and the output terminal of another stage switching circuit.

[0010] In one possible embodiment of this application, the first end of any compensation capacitor is connected to the input or output of the i-th stage switching circuit, and the second end of any compensation capacitor is connected to the gate control terminal of the j-th stage switching circuit. The first ends of different compensation capacitors are connected to the input or output of different switching circuits, where i is an integer greater than or equal to 1 and less than or equal to N-1, and j is greater than or equal to i+1 and less than or equal to N. This scheme can compensate for the gate and drain capacitances in each stage of the switching circuit by bridging the compensation capacitors.

[0011] In one possible implementation of this application, the j-th stage switching circuit is the next stage switching circuit after the i-th stage switching circuit. This scheme can achieve capacitance compensation between adjacent switching circuits using a bridging capacitor.

[0012] In one possible implementation of this application, at least one cascaded switching circuit is connected between the j-th stage switching circuit and the i-th stage switching circuit. This scheme can achieve capacitance compensation of multi-stage switching circuits using bridging capacitors.

[0013] In one possible implementation of this application, the switching circuit includes: a first switching transistor; wherein, the first end of the first switching transistor serves as the input end of the switching circuit, used to connect to the output end of the previous stage switching circuit or the input end of the radio frequency switch; the second end of the first switching transistor serves as the gate control end of the switching circuit; and the third end of the first switching transistor serves as the output end of the switching circuit, used to connect to the input end of the next stage switching circuit or the output end of the radio frequency switch.

[0014] In one possible implementation of this application, the switching circuit further includes a second switching transistor. The second terminal of the first switching transistor is connected to both the first and second terminals of the second switching transistor, and the body terminal of the first switching transistor is connected to the third terminal of the second switching transistor.

[0015] In one possible implementation of this application, the first terminal is the drain, the third terminal is the source, and the second terminal is the gate; wherein, a first resistor is connected in series between the first terminal and the third terminal of the first switching transistor.

[0016] In one possible implementation of this application, the gate control terminal of any switching circuit is connected to one end of a second resistor. The other end of the second resistor is connected to one end of a third resistor. The other end of the third resistor is used to receive a control signal.

[0017] In one possible implementation of this application, the first switching transistor and the second switching transistor are N-type MOS transistors or P-type MOS transistors.

[0018] Secondly, embodiments of this application provide a switch that includes the capacitor compensation circuit described in the first aspect or various possible implementations of the first aspect. For example, the switch can be a radio frequency switch.

[0019] Thirdly, embodiments of this application provide a radio frequency circuit, which includes a radio frequency switch as described in the second aspect or various possible implementations of the second aspect.

[0020] In one possible implementation of this application, the radio frequency circuit further includes a transmitting port and a receiving port, both of which are connected to an antenna. The transmitting port is connected to a first terminal of a first radio frequency switch, and a second terminal of the first radio frequency switch is connected to the antenna. The first terminal of the transmitting port is also grounded through a second radio frequency switch. The receiving port is connected to the antenna through a third radio frequency switch and is also grounded through a fourth radio frequency switch. The third radio frequency switch and the second radio frequency switch are radio frequency switches as described in the second aspect or various possible implementations of the second aspect.

[0021] In one possible implementation of this application, the radio frequency circuit further includes at least one tuning circuit connected to the antenna. Each tuning circuit includes one or more tuning branches, and any of the tuning branches includes a switch connected to the antenna and a load connected to the switch, the load being grounded. Any switch employs a radio frequency switch as described in the second aspect or various possible implementations of the second aspect.

[0022] Fourthly, embodiments of this application provide a communication device, the communication device including: a radio frequency front-end module, the radio frequency front-end module including a radio frequency circuit as described in the third aspect or various possible implementations of the third aspect or a radio frequency switch as described in the second aspect or various possible implementations of the second aspect. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the application of the radio frequency switch provided in this application in different scenarios;

[0024] Figure 2 This application provides an equivalent model of a high-voltage withstand frequency switch and an equivalent schematic diagram of uneven voltage distribution in the related technologies.

[0025] Figure 3 This is a schematic diagram of the source-drain capacitance compensation structure provided in related technologies;

[0026] Figure 4 yes Figure 3 The simulation benefit curve of the source-drain capacitance compensation structure is shown below.

[0027] Figure 5 This is a schematic diagram of another source-drain capacitance compensation structure provided in related technologies;

[0028] Figure 6 This is a schematic diagram of a capacitor compensation structure provided in an embodiment of this application;

[0029] Figure 7 This is a schematic diagram of a specific structure of a capacitor compensation structure provided in an embodiment of this application;

[0030] Figure 8 This is a schematic diagram of a capacitor compensation structure that performs capacitor compensation step by step in the related technology provided in the embodiments of this application;

[0031] Figures 9A to 9C These are simulation diagrams of different capacitor compensation structures provided in the embodiments of this application;

[0032] Figure 10 This is a schematic diagram comparing the layout area and Coff results of different capacitor compensation structures provided in the embodiments of this application;

[0033] Figure 11This is a schematic diagram of another capacitor compensation structure provided in the embodiments of this application;

[0034] Figure 12 Specific structural diagrams of different capacitor compensation structures provided in the embodiments of this application;

[0035] Figures 13-15 Simulation diagrams of different capacitor compensation structures are shown.

[0036] Figure 16 This is a schematic diagram comparing the layout area and Coff results of different capacitor compensation structures provided in the embodiments of this application;

[0037] Figure 17 This is a schematic diagram illustrating an application scenario of a radio frequency switch provided in an embodiment of this application;

[0038] Figure 18 This is a schematic diagram illustrating another application scenario of a radio frequency switch provided in an embodiment of this application. Detailed Implementation

[0039] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0040] In the description of this application, unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship. For example, A / B can represent A or B. "And / or" in this application merely describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone, where A and B can be singular or plural. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple. Additionally, to facilitate a clear description of the technical solutions of the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the words "first" and "second" do not limit the quantity or the order of execution, and that the words "first" and "second" do not necessarily imply that they are different.

[0041] In the various method embodiments of this application, the order of the sequence numbers does not imply the order of execution. The execution order should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0042] It is understood that in this application, descriptions such as "under the circumstances," "if," "when," and "if..." can be used interchangeably. Furthermore, these descriptions all refer to the corresponding actions that will be taken under certain objective circumstances, and are not time-limited, nor do they require any judgment action during implementation, nor do they imply any other limitations.

[0043] It is understood that in this application, "greater than or equal to" can be replaced with "greater than", and correspondingly, "less than" can also be replaced with "less than or equal to".

[0044] It is understood that some optional features in the embodiments of this application can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the apparatus given in the embodiments of this application can also implement these features or functions, which will not be elaborated here.

[0045] In this application, unless otherwise specified, the same or similar parts between the various embodiments can be referred to each other. In the various embodiments of this application, and in the various implementation methods / methods / implementations within each embodiment, unless otherwise specified or logically conflicting, the terminology and / or descriptions between different embodiments and between the various implementation methods / methods / implementations within each embodiment are consistent and can be mutually referenced. The technical features in different embodiments and the various implementation methods / methods / implementations within each embodiment can be combined according to their inherent logical relationships to form new embodiments, implementation methods, methods, or implementation approaches. The embodiments described below do not constitute a limitation on the scope of protection of this application.

[0046] The capacitor compensation circuit provided in this application embodiment can be applied to radio frequency switches, which can be used in the radio frequency front-end modules of communication devices such as terminals and network devices (e.g., base stations). For example, the terminal in this application embodiment can be a smartphone, tablet computer, laptop computer, customer premises equipment (CPE), router, smart bracelet, smartwatch, smart helmet, smart glasses, and other devices. The terminal 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, vehicle-mounted device, electronic device in a 5G network, or terminal device in a future public land mobile network (PLMN), etc. The embodiments of this application do not limit this to terminals using 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.

[0047] like Figure 1 As shown in (a), taking the use of RF switches in a transceiver communication scenario as an example, in the transmission scenario, when switch 3 is closed and switch 4 is open in the transmission path connected in series between the transmit end (TX) and the antenna (ANT), and switch 2 is open and switch 1 is on in series between the receive end (RX) and the antenna, the RF signal can be transmitted from the RF chip to the antenna after being amplified by the power amplifier. However, during the signal transmission process, since switch 4 is grounded and open, and switch 2 is open, the two ends of switch 2 and switch 4 will bear a relatively large voltage difference from the RF front end. Moreover, the existence of the die parasitic effect of switch 2 and switch 4 will cause the voltage swing of each switch tube to be unequal when switch 2 and switch 4 include multiple stages of switching tubes, resulting in poor voltage withstand capability of the switch, which can easily lead to die breakdown of the front-end switch tube, and then the entire switch burns out and fails.

[0048] like Figure 1 As shown in (b), the application of an RF switch as an antenna switch in a high-voltage scenario is illustrated. Figure 1 As shown in (b), one end of the antenna is grounded and the other end is connected to the radio frequency front-end module of the communication device. In order to adjust the frequency of the antenna, the antenna is also connected to one or more tuning circuits. Any tuning circuit may include multiple tuning sub-circuits. Any tuning sub-circuit includes a radio frequency switch and a load. One end of the load is connected to the radio frequency switch and the other end of the load is grounded.

[0049] For example, such as Figure 1 As shown in (b), the antenna can also be connected to tuning circuit 101 and tuning circuit 102. Taking any tuning circuit as an example, which includes three tuning sub-circuits, tuning circuit 101 includes tuning sub-circuit 1011, tuning sub-circuit 1012, and tuning sub-circuit 1013. Tuning sub-circuit 1011 includes RF switch 1011a and load 1011b. One end of RF switch 1011a is connected to the antenna, and the other end of RF switch 1011a is connected to load 1011b. The other end of load 1011b is grounded.

[0050] The tuner circuit 1012 includes an RF switch 1012a and a load 1012b. One end of the RF switch 1012a is connected to an antenna, and the other end of the RF switch 1012a is connected to the load 1012b. The other end of the load 1012b is grounded.

[0051] The tuner circuit 1013 includes an RF switch 1013a and a load 1013b. One end of the RF switch 1013a is connected to the antenna, and the other end of the RF switch 1013a is connected to the load 1013b. The other end of the load 1013b is grounded.

[0052] The tuning circuit 102 includes a tuning sub-circuit 1021, a tuning sub-circuit 1022, and a tuning sub-circuit 1023. The tuning sub-circuit 1021 includes an RF switch 1021a and a load 1021b. One end of the RF switch 1021a is connected to an antenna, and the other end of the RF switch 1021a is connected to the load 1021b. The other end of the load 1021b is grounded.

[0053] The tuner circuit 1022 includes an RF switch 1022a and a load 1022b. One end of the RF switch 1022a is connected to an antenna, and the other end of the RF switch 1022a is connected to the load 1022b. The other end of the load 1022b is grounded.

[0054] The tuner circuit 1023 includes an RF switch 1023a and a load 1023b. One end of the RF switch 1023a is connected to the antenna, and the other end of the RF switch 1023a is connected to the load 1023b. The other end of the load 1023b is grounded.

[0055] In practical applications, at least one tuning sub-circuit may be on in any tuning circuit, while the others may be off. For example, if RF switch 1011a is closed, tuning sub-circuit 1011 is on; if RF switch 1012a is open, tuning sub-circuit 1012 is off. When tuning sub-circuit 1012 is off, since the load 1012b in tuning sub-circuit 1012 is grounded, the voltage at the end of RF switch 1012a connected to the load is 0. However, the voltage at the end of RF switch 1012a connected to the antenna is usually not 0. For example, the voltage at the end of RF switch 1012a connected to the antenna can usually be the RF voltage output by the RF front-end module. This will result in a relatively large RF voltage difference at RF switch 1012a.

[0056] Since RF switches are typically formed by cascading multiple switching circuits, each circuit includes at least one switching transistor. Ideally, each stage of the switching circuit should withstand an equal voltage drop. Figure 2 As shown in (a), ideally, with the RF switch on, the voltage between the source and drain of each stage of the switch (referred to as the source-drain voltage) should be equal, meaning the voltage drop across each stage should be equal. However, due to the additional leakage current introduced by the losses in the gate and substrate of the switch die, and the inconsistent source-drain voltage values ​​across each stage, the voltage drop across each stage becomes uneven, as shown in (a). Figure 2 As shown in (b) above. Specifically, the losses in the gate and substrate of the switching transistor introduce additional leakage current. The voltage drop across the first few stages of the switching transistor is usually relatively large, while the voltage drop across the later stages is usually relatively small, such as... Figure 2 In the diagram, (d) represents the equivalent capacitance model of each stage of the switching transistors in the circuit structure shown, such as... Figure 2 As can be seen from (c) in the figure, the voltage drop of the die of each switching transistor decreases sequentially from high voltage to low voltage.

[0057] In order to achieve uniform voltage distribution of the switching transistor under high voltage, a body-terminal compensation capacitor Cbb can be connected across the body (sometimes called the substrate) of each adjacent switching transistor, and a feedforward capacitor C_fwd can be connected between the body of the first-stage field-effect transistor (FET) 1 and the source of the first-stage FET 1.

[0058] like Figure 3As shown in (a), the capacitor compensation circuit includes five field-effect transistors, i.e., five stages of field-effect transistors. For example, a body-end compensation capacitor Cbb1 can be connected between the body terminal of the first-stage FET1 and the body terminal of the second-stage FET2. A body-end compensation capacitor Cbb2 can be connected between the body terminal of the second-stage FET2 and the body terminal of the third-stage FET3. A body-end compensation capacitor Cbb3 can be connected between the body terminal of the third-stage FET3 and the body terminal of the fourth-stage FET4. A body-end compensation capacitor Cbb4 can be connected between the body terminal of the fourth-stage FET4 and the body terminal of the fifth-stage FET5. Any body-end compensation capacitor Cbb can equivalently compensate for the capacitance between the source and drain of each stage, balancing the capacitance of each stage. The body-end bridging capacitors are connected to the body terminals of adjacent stages to achieve uniform voltage distribution of the switching transistors under high voltage.

[0059] like Figure 3 As shown in (b), a feedforward capacitor C_fwd and a feedforward resistor R_fwd can be connected between the body terminal of the first-stage field-effect transistor (FET) 1 and its source. A body-terminal compensation resistor Rbb can be connected across the body terminal of each stage of the switching transistor. For example, a body-terminal compensation resistor Rbb1 can be connected between the body terminal of the first-stage FET 1 and the body terminal of the second-stage FET 2; a body-terminal compensation resistor Rbb2 can be connected between the body terminal of the second-stage FET 2 and the body terminal of the third-stage FET 3; a body-terminal compensation resistor Rbb3 can be connected between the body terminal of the third-stage FET 3 and the body terminal of the fourth-stage FET 4; and a body-terminal compensation resistor Rbb4 can be connected between the body terminal of the fourth-stage FET 4 and the body terminal of the fifth-stage FET 5. Any body-terminal compensation resistor Rbb can effectively compensate for the source-drain capacitance of each stage, balancing the capacitance of each stage. The body-terminal compensation resistors are connected to the body terminals of adjacent stages to achieve uniform voltage distribution of the switching transistors under high voltage.

[0060] like Figure 4 As shown, Figure 4 For example Figure 3 The circuit diagram and simulation benefit curve of the compensation circuit are shown. Figure 4 Curve 1 shows the voltage drop of each stage of the switching circuit without the cross-connection compensation capacitor. It can be seen from Curve 1 that the voltage drop is the largest in the first stage of the switching circuit, and the voltage drop of each stage of the switching circuit gradually decreases after the first stage. The voltage drop of each stage of the switching circuit is quite different, and the voltage swing of each stage of the switching circuit is not uniform. Curve 2 shows the voltage drop of each stage of the switching circuit with the cross-connection compensation capacitor. It can be seen from Curve 2 that after adding the cross-connection compensation capacitor, the voltage drop of each stage of the switching circuit does not vary much, and the voltage swing of each stage of the switching circuit tends to be uniform.

[0061] Although Figure 3The scheme shown can balance the voltage of each stage of the switching transistor by using a body-terminal compensation capacitor Cbb and a body-terminal feedforward capacitor & body-terminal bridging resistor Rbb for each stage, resulting in a uniform voltage distribution across stages. However, since the actual values ​​of the body-terminal compensation capacitor Cbb and the body-terminal feedforward capacitor & body-terminal bridging resistor Rbb for each stage may not be the same, the actual values ​​of the body-terminal compensation capacitor Cbb and the body-terminal feedforward capacitor & body-terminal bridging resistor Rbb for each stage need to be calculated through simulation. Generally, the capacitor is on the order of fF, and fluctuations in actual manufacturing parameters can lead to large fluctuations in the actual capacitor value, resulting in poor consistency of actual capacitor compensation and poor voltage balancing effect.

[0062] like Figure 5 As shown, an additional capacitor CB is connected in parallel between the source and drain of each switching transistor. For example, as... Figure 5 As shown, capacitor CB1 can be connected in parallel between the drain and source of switching transistor M1, capacitor CB2 between the source and drain of switching transistor M2, capacitor CB3 between the source and drain of switching transistor M3, and so on. A capacitor CBN can be connected in parallel between the source and drain of switching transistor MN to compensate for C_ds, balance the capacitance of each switching transistor, and thus balance the voltage drop of each stage.

[0063] Although Figure 5 The structure shown can ensure that the voltage drop across each stage of the switching circuit is uniform. However, in high-voltage scenarios, the number of CBN capacitor compensation stages is large, which increases the capacitance value C_off from the input to the output of the RF switch in the off state. Generally, the smaller the capacitance value C_off, the stronger the RF switch's ability to block RF signals and the better the isolation. The larger the capacitance value C_off, the lower the RF switch's ability to block RF signals and the worse the isolation. This will lead to more RF signal leakage and deteriorate the figure-of-merit (FOM) value of the RF switch.

[0064] Based on this, embodiments of this application provide a capacitor compensation circuit, an RF switch, and a communication device. This solution uses a compensation capacitor connected in series between at least two stages of a multi-stage switching circuit; that is, any compensation capacitor is connected across at least two stages of the switching circuit. This allows for capacitor compensation for each stage of the at least two-stage switching circuit, resulting in a more balanced voltage swing for each stage. Furthermore, by using a compensation capacitor across at least two stages of the switching circuit, this solution reduces the number of compensation capacitors, lowering the total capacitance value of the capacitor compensation circuit in both on and off states. A lower total capacitance value allows the RF switch to have stronger blocking capability and better isolation of RF signals. The lower capacitance value also addresses the problem of excessive degradation in the total resistance R_ON in the on state and the total capacitance C_OFF in the off state.

[0065] like Figure 6 As shown, Figure 6 This is a schematic diagram of a capacitor compensation circuit provided in an embodiment of this application. The capacitor compensation circuit can be applied to a switch (such as a radio frequency switch). The radio frequency switch has an input terminal 601 and an output terminal 602.

[0066] The capacitor compensation circuit includes: N sequentially connected (or cascaded) switching circuits 603 (e.g., first-stage switching circuit 6031, second-stage switching circuit 6032, third-stage switching circuit 6033, ..., N-1th-stage switching circuit 603(N-1), and Nth-stage switching circuit 603N (also known as the last-stage switching circuit)) and at least one compensation capacitor 604.

[0067] Each stage of the N-stage switching circuit 603 has an input terminal, an output terminal, and a gate control terminal. The output terminal of the previous stage of the N-stage switching circuit 603 is connected to the input terminal of the next stage of the switching circuit 603. The input terminal of the first stage switching circuit 6031 in the multiple cascaded switching circuits 603 is connected to the input terminal 601 of the RF switch, and the output terminal of the last stage switching circuit 603N in the multiple cascaded switching circuits 603 is connected to the output terminal 602 of the RF switch.

[0068] At least one compensation capacitor is included. For example, compensation capacitors 6041 to 604M, with any one of the compensation capacitors 604 connected across at least two switching circuits 603. That is, in this embodiment, a compensation capacitor 604 is connected between any at least two switching circuits 603. In other words, one end of the compensation capacitor 604 is connected to one switching circuit, and the other end is connected to another switching circuit. N is an integer greater than or equal to 2.

[0069] Any compensation capacitor 604 can provide capacitance compensation for at least two stages of switching circuits 603. N is an integer greater than or equal to 2. When N equals 2, it indicates that the capacitance compensation circuit includes two stages of switching circuits 603. In this case, M can be equal to 1, meaning that only one compensation capacitor 604 is needed to provide capacitance compensation for two stages of switching circuits 603. M is an integer greater than or equal to 1.

[0070] In the capacitor compensation circuit provided in this application embodiment, since a compensation capacitor 604 is connected between at least two stages of switching circuits 603, each compensation capacitor 604 can compensate the die of at least two stages of switching circuits 603. Any compensation capacitor 604 can achieve capacitance compensation for multiple stages of switching circuits 603, resulting in a more balanced voltage swing at each stage. Moreover, since the compensation capacitor is connected between at least two stages of switching circuits, the total compensation value of this capacitor compensation circuit is lower. Therefore, this solution can achieve a more balanced voltage swing at each stage while minimizing the degradation of key indicators such as the total resistance R_ON of the RF switch in the on state and the total capacitance C_OFF in the off state. It can simultaneously achieve a high-performance switch with high withstand voltage, low resistance R_ON, and low total capacitance C_OFF in the off state.

[0071] From the input terminal 601 to the output terminal 602 of the RF switch, except for the first-stage switch circuit 6031 and the last-stage switch circuit 603N, each stage switch circuit 603 has a connected previous-stage switch circuit 603 and a next-stage switch circuit 603. For example, the previous-stage switch circuit 603 of the second-stage switch circuit 6032 is the first-stage switch circuit 6031. The next-stage switch circuit 603 of the second-stage switch circuit 6032 is the third-stage switch circuit 6033.

[0072] In one possible embodiment of this application, the sizes of the different compensation capacitors 604 in the capacitor compensation circuit can be the same or different. The size of any compensation capacitor 604 can be determined by simulating the voltage swing of each stage of the switching circuit in the circuit, and selecting the compensation capacitance value that makes the voltage swing of each stage of the switching circuit most uniform.

[0073] In one possible embodiment of this application, the number of stages of the switching circuits 603 that different compensation capacitors 604 can be connected to may be the same or different. For example, one compensation capacitor 604 can be connected between the input terminal of one switching circuit 603 and the output terminal or gate control signal terminal of the next stage switching circuit 603. Another compensation capacitor 604 can be connected between the input terminal of one switching circuit 603 and the output terminal or gate control signal terminal of the next-next stage switching circuit 603.

[0074] In one possible embodiment of this application, any compensation capacitor 604 connected across at least two switching circuits 603 can mean that any compensation capacitor 604 is connected in series between the first terminal of any one switching circuit 603 and the second terminal of another switching circuit 603. The first terminals of different compensation capacitors 604 are connected to the first terminals of different switching circuits.

[0075] As an example, in a scenario where source-drain capacitance compensation is required for each stage of the switching circuit, the first terminal of the i-th stage switching circuit 603 can refer to the input terminal of the i-th stage switching circuit 603. The second terminal of the i-th or j-th stage switching circuit 603 can refer to the output terminal of the i-th or j-th stage switching circuit 603. That is, the first terminal of any compensation capacitor 604 is connected to the input terminal of the i-th stage switching circuit 603, and the second terminal of any compensation capacitor 604 is connected to the output terminal of the j-th stage switching circuit 603. i is an integer greater than or equal to 1 and less than or equal to N-1, and j is greater than or equal to i+1 and less than or equal to N.

[0076] As an example, in a scenario where gate-drain capacitance compensation is required for each stage of the switching circuit, the first terminal of the i-th stage switching circuit 603 can refer to either the input or output terminal of the i-th stage switching circuit 603. The second terminal of the i-th or j-th stage switching circuit 603 can refer to the gate control terminal of the i-th or j-th stage switching circuit 603. That is, the first terminal of any compensation capacitor 604 is connected to either the input or output terminal of the i-th stage switching circuit 603, and the second terminal of any compensation capacitor 604 is connected to the gate control terminal of the i-th or j-th stage switching circuit 603. The first terminals of different compensation capacitors 604 are connected to the input or output terminals of different switching circuits 603.

[0077] In one possible implementation of this application, for example, j = i + 1, then the j-th level switching circuit 603 is the next level switching circuit after the i-th level switching circuit 603. Alternatively, for example, j = i + 2, i + 3, or i + 4, indicating that at least one level of switching circuit 603 is cascaded between the j-th level switching circuit 603 and the i-th level switching circuit 603. For example, j = i + 2 indicates that one level of switching circuit 603 is cascaded between the j-th level switching circuit 603 and the i-th level switching circuit 603. If the i-th level switching circuit 603 is the second level switching circuit, then the j-th level switching circuit 603 is the fourth level switching circuit, and a third level switching circuit exists between the second and fourth level switching circuits. If j = i + 3, it means that there are two cascaded switching circuits 603 between the j-th level switching circuit 603 and the i-th level switching circuit 603. If i = 1, then j = 4. Therefore, the i-th level switching circuit 603 is the first level switching circuit, and the j-th level switching circuit 603 is the fourth level switching circuit. There are also a second level switching circuit and a third level switching circuit between the first level switching circuit and the fourth level switching circuit.

[0078] For example, the i-th stage switch circuit 603 can refer to the first stage switch circuit 6031 mentioned above, and the j-th stage switch circuit 603 can refer to the second stage switch circuit 6032, that is, a compensation capacitor 604 is connected in series between the first terminal of the first stage switch circuit 6031 and the second terminal of the second stage switch circuit 6032.

[0079] For example, the i-th stage switch circuit 603 can refer to the first stage switch circuit 6031 mentioned above, and the j-th stage switch circuit 603 can refer to the third stage switch circuit 6033, or a switch circuit 603 located after the third stage switch circuit 6033. For example, a compensation capacitor 604 can be connected in series between the first terminal of the first stage switch circuit 6031 and the second terminal of the third stage switch circuit 6033. In this case, the compensation capacitor 604 can be used to compensate for the first stage switch circuit 6031, the second stage switch circuit 6032, and the third stage switch circuit 6033.

[0080] In one possible embodiment of this application, the first end of any compensation capacitor 604 is connected to the input terminal of the i-th stage switching circuit 603, and the second end of any compensation capacitor 604 is connected to the output terminal of the j-th stage switching circuit 603. The first ends of different compensation capacitors 604 are connected to the input terminals of different switching circuits 603.

[0081] In the embodiments of this application, the structures of the N switching circuits may be the same or different. The following description takes any switching circuit 603 including a first switching transistor as an example.

[0082] The first terminal of the first switching transistor serves as the input terminal of the switching circuit 603, which is used to connect to the output terminal of the previous stage switching circuit 603 or to the input terminal of the radio frequency switch.

[0083] The second terminal of the first switching transistor serves as the control signal receiving terminal of the switching circuit. The third terminal of the first switching transistor serves as the output terminal of the switching circuit, used to connect to the input terminal of the next stage switching circuit or the output terminal of the radio frequency switch.

[0084] In one possible embodiment of this application, any switching circuit 603 may further include a second switching transistor. The body terminal of the first switching transistor is connected to the third terminal of the second switching transistor. The first terminal and the second terminal of the second switching transistor are shared and both connected to the second terminal of the first switching transistor. In this embodiment, by providing a second switching transistor in each switching circuit, the body terminal of the first switching transistor can be compensated using the second switching transistor.

[0085] In one possible embodiment of this application, the first terminal of any switch is the drain, the third terminal of any switch is the source, and the second terminal of any switch is the gate.

[0086] In one possible embodiment of this application, to achieve voltage compensation for each stage of the switching circuit, a first resistor is connected in series between the input and output terminals of any switching circuit. For example, a first resistor is also connected in series between the first terminal and the third terminal of the first switching transistor.

[0087] In one possible embodiment of this application, the gate control terminal of any switching circuit 603 is connected to one end of a second resistor, the other end of the second resistor is connected to one end of a third resistor, and the other end of the third resistor is used to receive a control signal.

[0088] like Figure 7 The diagram shown is a schematic representation of a capacitor compensation circuit suitable for compensating source and drain capacitances, provided in an embodiment of this application. Figure 7 The capacitor compensation circuit shown in (a) includes: a first-stage switch circuit 6031, a second-stage switch circuit 6032, a third-stage switch circuit 6033, a fourth-stage switch circuit 6034, a fifth-stage switch circuit 6035, a sixth-stage switch circuit 6036, ..., a N-2 stage switch circuit 603(N-2) and an Nth-stage switch circuit 603N, which are connected in sequence.

[0089] It is understandable that the first-stage switching circuit 6031 and the second-stage switching circuit 6032 may or may not have a switching circuit between them. If there are no other switching circuits between the first-stage switching circuit 6031 and the second-stage switching circuit 6032, then the second-stage switching circuit 6032 is the next-stage switching circuit after the first-stage switching circuit 6031. Similarly, the second-stage switching circuit 6032 and the third-stage switching circuit 6033 may or may not have a switching circuit between them; the third-stage switching circuit 6033 and the fourth-stage switching circuit 6034 may or may not have a switching circuit between them; the fourth-stage switching circuit 6033 and the fifth-stage switching circuit 6035 may or may not have a switching circuit between them; and so on. The (N-1)th stage switching circuit (not shown in the figure) and the Nth stage switching circuit 603N may or may not have a switching circuit between them.

[0090] The first-stage switching circuit 6031 includes switching transistors Q11 and Q12. The second-stage switching circuit 6032 includes switching transistors Q21 and Q22. The third-stage switching circuit 6033 includes switching transistors Q31 and Q32. The fourth-stage switching circuit 6034 includes switching transistors Q41 and Q42. The fifth-stage switching circuit 6035 includes switching transistors Q51 and Q52. The sixth-stage switching circuit 6036 includes switching transistors Q61 and Q62. ... The (N-2)th stage switching circuit 603(N-2) includes switching transistors Q(N-2)1 and Q(N-2)2. The Nth stage switching circuit 603N includes switching transistors QN1 and QN2.

[0091] In this circuit, the drain (D) of transistor Q11 serves as the input terminal of the first-stage switching circuit 6031, connecting to the input terminal 601 of the RF switch. The gate (G) of transistor Q11 is connected to the gate (G) of transistor Q12 and the drain of transistor Q12. The source (S) of transistor Q11 serves as the output terminal of the first-stage switching circuit 6031, connecting to the input terminal of the second-stage switching circuit 6032. The body of transistor Q11 is connected to the source (S) of transistor Q12. A resistor R11 (corresponding to the first resistor) is connected in series between the drain (D) and source (S) of transistor Q11. The gate (G) of transistor Q11 is connected to the gate (G) of transistor Q12 and the drain of transistor Q12, and is connected to one end of a diode gate resistor (corresponding to the third resistor) through resistor R12 (corresponding to the second resistor). The other end of the diode gate resistor is used to receive control signals.

[0092] The drain (D) of transistor Q21 serves as the input of the second-stage switching circuit 6032, connecting to the output of the first-stage switching circuit 6031 (i.e., the source (S) of transistor Q11). The gate (G) of transistor Q21 is connected to the gate (G) of transistor Q22 and its drain (D). The source of transistor Q21 serves as the output of the second-stage switching circuit 6032, connecting to the input of the third-stage switching circuit 6033. The body of transistor Q21 is connected to the source (S) of transistor Q22. A resistor R21 is connected in series between the drain (D) and source (S) of transistor Q21. The gate (G) of transistor Q21, the gate (G) of transistor Q22, and the drain of transistor Q22 are all connected together and are connected to one end of a diode gate resistor via resistor R22. The other end of the diode gate resistor is used to receive control signals.

[0093] The drain (D) of switching transistor Q31 serves as the input terminal of the third-stage switching circuit 6033, connecting to the output terminal of the second-stage switching circuit 6032 (i.e., the source (S) of switching transistor Q21). The gate (G) of switching transistor Q31 is connected to the gate (G) of switching transistor Q32 and its drain (D). The source of switching transistor Q31 serves as the output terminal of the third-stage switching circuit 6033, connecting to the input terminal of the fourth-stage switching circuit (not shown in the figure). The body of switching transistor Q31 is connected to the source (S) of switching transistor Q32. A resistor R31 is connected in series between the drain (D) and source (S) of switching transistor Q31. The gate (G) of switching transistor Q31 is connected to the gate (G) of switching transistor Q32 and the drain (D) of switching transistor Q32, and is connected to one end of a diode gate resistor through resistor R32. The other end of the diode gate resistor is used to receive control signals.

[0094] The drain (D) of switching transistor Q41 serves as the input of the fourth-stage switching circuit 6034, connecting to the output of the third-stage switching circuit 6033 (i.e., the source (S) of switching transistor Q31). The gate (G) of switching transistor Q41 is connected to the gate (G) of switching transistor Q42 and its drain (D). The source of switching transistor Q41 serves as the output of the fourth-stage switching circuit 6034, connecting to the input of the fifth-stage switching circuit 6035. The body of switching transistor Q41 is connected to the source (S) of switching transistor Q42. A resistor R41 is connected in series between the drain (D) and source (S) of switching transistor Q41. The gate (G) of switching transistor Q41 is connected to the gate (G) of switching transistor Q42 and its drain (D), and is connected to one end of a diode gate resistor R3 via resistor R42. The other end of the diode gate resistor R3 is used to receive control signals.

[0095] The drain (D) of transistor Q51 serves as the input of the fifth-stage switching circuit 6035, connecting to the output of the fourth-stage switching circuit 6034 (i.e., the source (S) of transistor Q41). The gate (G) of transistor Q51 is connected to the gate (G) of transistor Q52 and its drain (D). The source of transistor Q51 serves as the output of the fifth-stage switching circuit 6054, connecting to the input of the sixth-stage switching circuit 6036. The body of transistor Q51 is connected to the source (S) of transistor Q52. A resistor R51 is connected in series between the drain (D) and source (S) of transistor Q51. The gate (G) of transistor Q51 is connected to the gate (G) of transistor Q52 and the drain (D) of transistor Q52, and is connected to one end of a diode gate resistor R3 via resistor R52. The other end of the diode gate resistor R3 is used to receive control signals.

[0096] The drain D of switch Q(N-2)1 serves as the input terminal of the (N-2)th stage switching circuit 603(N-2), connecting to the output terminal of the (N-3)th stage switching circuit 603(N-3) (i.e., the source S of switch Q(N-3)1). The gate G of switch Q(N-2)1 is connected to the gate G of switch Q(N-2)2 and the drain D of switch Q(N-2)2. The source of switch Q(N-2)1 serves as the output terminal of the (N-2)th stage switching circuit 605(N-2), connecting to the input terminal of the (N-1)th stage switching circuit 603(N-1). The body of switch Q(N-2)1 is connected to the source S of switch Q(N-2)2. A resistor R(N-2)1 is connected in series between the drain D of switch Q(N-2)1 and the source S of switch Q(N-2)1. The gate G of switch Q(N-2)1 is connected to the gate G of switch Q(N-2)2 and the drain D of switch Q(N-2)2. They are connected to one end of the diode gate resistor R3 through resistor R(N-2)2. The other end of the diode gate resistor R3 is used to receive control signals.

[0097] The drain D of switch QN1 serves as the input terminal of the Nth-stage switching circuit 603N, connecting to the output terminal of the (N-1)th-stage switching circuit 603(N-1) (i.e., the source S of switch Q(N-1)1). The gate G of switch QN1 is connected to the gate G of switch QN2 and the drain D of switch QN2. The source of switch QN1 serves as the output terminal of the Nth-stage switching circuit 603N, connecting to the output terminal of the RF switch. The body of switch QN1 is connected to the source S of switch QN2. A resistor RN1 is connected in series between the drain D of switch QN1 and the source S of switch QN1. The gate G of switch QN1, the gate G of switch QN2, and the drain D of switch QN2 are all connected together and are connected to one end of a diode gate resistor through resistor RN2. The other end of the diode gate resistor is used to receive control signals.

[0098] like Figure 7As shown in (a), compensation capacitor 6041 is connected across the drain D of switching transistor Q11 and the source S of switching transistor Q31. That is, one end of compensation capacitor 6041 is connected to the drain D of switching transistor Q11, and the other end is connected to the source S of switching transistor Q31. Switching transistor Q31 is the switching transistor in the third-stage switching circuit 6033, and switching transistor Q11 is the switching transistor in the first-stage switching circuit 6031. The third-stage switching circuit 6033 is the next-next-stage switching circuit after the first-stage switching circuit 6031. Compensation capacitor 6042 is connected in series between the drain D of switching transistor Q21 and the source S of switching transistor Q41. Compensation capacitor 6043 is connected in series between the drain D of switching transistor Q31 and the source S of switching transistor Q51. Compensation capacitor 6044 is connected in series between the drain D of switching transistor Q41 and the source S of switching transistor Q61. The compensation capacitor 604M is connected in series between the drain D of the switching transistor Q(N-2)1 and the source S of the switching transistor QN1.

[0099] It is worth noting that, Figure 7 Example (a) illustrates this by connecting a compensation capacitor in series between the input terminal of any first-stage switching circuit 603 and the output terminal of the next-next-stage switching circuit 603. In practice, the compensation capacitor can also be connected across at least three switching circuits or in series between the input and output terminals of two adjacent switching circuits. For example, Figure 7 In (b), compensation capacitor 6041 is connected between the drain D of switch Q11 in the first-stage switching circuit 6031 and the source S of switch Q21 in the second-stage switching circuit 6032. Alternatively, compensation capacitor 1 is connected between the drain D of switch Q11 in the first-stage switching circuit 6031 and the source S of switch Q41 in the fourth-stage switching circuit 6034. This embodiment of the application does not limit this.

[0100] like Figure 8 As shown, Figure 8 (a) in the diagram is a schematic diagram of a capacitor compensation circuit in the related technology, where each stage of the switching circuit performs capacitor compensation. Figure 8 As shown, Figure 8 Taking a 17-stage switching circuit as an example, each stage of the switching circuit has a compensation capacitor and a resistor connected between its input and output terminals, for example... Figure 8 Capacitors 1 to N, and resistors R11, R21, R31, R41, ..., R171, are shown in diagram (a). Compensation capacitors connected in series at the input and output terminals of each switching circuit are connected in parallel with resistors connected in series at the input and output terminals of each switching circuit. For example... Figure 8 (b) in the text represents a scheme in the related technology where resistors are connected in series at the input and output terminals of each stage of the switching circuit to compensate for the source and drain, such as... Figure 8The resistors shown in (b) are R11, R21, R31, R41, ..., R171.

[0101] like Figure 9A As shown, Figure 9A As provided in the embodiments of this application Figure 7 Simulation results of the capacitor compensation circuit shown in (b) are shown below; Figure 9B and Figure 9C They are respectively as follows Figure 8 Simulation results of the capacitor compensation circuit shown in (a) and (b) are shown. Figure 7 (b) in the middle and as in Figure 8 The capacitor compensation circuits shown in (a) and (b) both have 17 cascaded switching circuits. Simulation results show that the embodiments of this application employ... Figure 7 The structure shown in (b) uses a compensation capacitor connected in series at the input and output of two adjacent switching circuits, such as... Figure 9A Figure (a) shows that the maximum swing of any single-stage switching circuit can be 3.48V, as shown in Figure (a). Figure 9A The insertion loss shown in Figure (b) is 0.253–0.294 dB, as... Figure 9A The isolation shown in Figure (c) is 27.6–38.2 dB. Using… Figure 8 The structure shown in (a) allows the maximum swing of any stage of the switching circuit to be maximized by connecting compensation capacitors in series at the input and output terminals of each stage, such as... Figure 9B (a) shows 3.48V, and the insertion loss is as follows: Figure 9B As shown in (b), the isolation ranges from 0.254 to 0.297 dB. Figure 9B (c) shows a range of 27.4–38 dB. Using... Figure 8 The structure shown in (b) allows for a maximum swing of 4.33V in any stage of the switching circuit by connecting compensation resistors in series at the input and output of each stage. Figure 9C As shown in (a), the insertion loss is 0.253–0.294 dB, as Figure 9C As shown in (b), the isolation is 28–38.6 dB, as Figure 9C As shown in (c) in the figure.

[0102] Simulation results show that, taking a 17-level switching circuit as an example, Figure 7 In the circuit structure shown in (b), due to the cross-stage placement of compensation capacitors, the first four stages require three compensation capacitors. The first compensation capacitor has a size of 140fF, the second compensation capacitor has a size of 30fF, and the third compensation capacitor has a size of 30fF. Figure 8In the circuit structure shown in (a), the first four stages of the switching circuit require four compensation capacitors: the first is 250fF, the second is 160fF, the third is 90fF, and the fourth is 40fF. Compared to Figure 8 (a) in the middle, Figure 7 The capacitor compensation circuit shown in (b) requires a lower capacitance value.

[0103] like Figure 10 As shown, Figure 10 for Figure 7 (b) Figure 8 (a) and Figure 8 The diagram (b) shows a comparison of the layout area of ​​the three capacitor compensation circuits and the total capacitance C_OFF when the RF switch is in the switching state, in a scenario where all circuits use a 17-stage switching circuit. Figure 7 The compensation capacitor area of ​​the circuit shown in (b) is 360 μm. 2 , Figure 8 The capacitor compensation area of ​​the circuit shown in (a) is 970 μm. 2 In the off state, Figure 7 The total capacitance C_OFF of the circuit shown in (b) is 75.2 fF in the off state. Figure 8 The total capacitance C_OFF of the circuit shown in (a) is 76.5fF. Figure 8 The total capacitance C_OFF of the circuit shown in (b) is 71.8 fF in the off state. A comparison shows that... Figure 7 The total compensation capacitor area shown in (b) is lower, and the total compensation capacitor area is [missing information]. Figure 8 37% of the circuit shown in (a) is... Figure 7 The total compensation capacitance of the capacitor compensation circuit shown in (b) is less than Figure 8 The total compensation capacitance of the circuit shown in (a) is low, making the compensation capacitance so that... Figure 7 The total capacitance C_OFF of the capacitor compensation circuit shown in (b) in the off state is compared to... Figure 8 (a) in the middle, Figure 7 The total capacitance C_OFF of the capacitor compensation circuit shown in (b) in the off state is compared to... Figure 8 The capacitor compensation circuit shown in (a) has a total capacitance value C_OFF that is 1.3fF lower in the off-state. In scenarios with lower stage numbers, the benefit of the total capacitance value C_OFF in the off-state is more significant. Moreover, the lower capacitance value of the compensation capacitor results in a smaller area of ​​the compensation capacitor, less parasitic interference to ground, and a lower impact on conduction and insertion losses. Figure 7The capacitor compensation circuit shown in (b) has 1-3 mdB better insertion loss than related technologies, and the benefits are more pronounced in low bump height packages.

[0104] like Figure 11 The diagram shown is a structural schematic of another capacitor compensation circuit provided in an embodiment of this application. Figure 11 The circuit shown is Figure 7 The difference between the circuit shown in (a) is that: Figure 11 Compensation capacitor 6041 is connected between the drain D of switching transistor Q11 and the gate G of switching transistor Q31, where switching transistor Q31 is the next-next stage switching transistor after switching transistor Q11. That is, compensation capacitor 6041 is connected between the drain D of switching transistor Q11 in the first-stage switching circuit 6031 and the gate of switching circuit 6033 in the third-stage switching circuit. Compensation capacitor 6032 is connected between the drain D of switching transistor Q21 and the gate G of switching transistor Q41. Compensation capacitor 6033 is connected between the drain D of switching transistor Q31 and the gate G of switching transistor Q51. Compensation capacitor 6034 is connected between the drain D of switching transistor Q41 and the gate G of switching transistor Q61. Compensation capacitor 6035 is connected between the drain D of switching transistor Q51 and the gate G of switching transistor Q71. Compensation capacitor 603M is connected between the drain D of switching transistor Q(N-2)1 and the gate G of switching transistor QN1.

[0105] It should be noted that, in Figure 11 In the circuit shown, the example is that the compensation capacitor 604 is connected across the drain D of a certain switching transistor and the gate G of the switching transistor in the next-next stage of the switching circuit where the switching transistor is located. In actual operation, the compensation capacitor 604 can also be connected across the drain D of a certain switching transistor and the gate G of the switching transistor in the next-next stage of the switching circuit where the switching transistor is located, or the compensation capacitor can be connected across the drain D of a certain switching transistor and the gate G of the switching transistor in a switching circuit with two, three, or even four or more stages between the switching transistor and the switching circuit where the switching transistor is located.

[0106] For example, the compensation capacitor 604 can also be connected across the drain D of a certain switching transistor and the gate G of the switching transistor in the next stage of the switching circuit where that switching transistor is located. Figure 12As shown in (a), compensation capacitor 6041 can be connected in series between the drain D of switching transistor Q11 and the gate G of switching transistor Q21, where switching transistor Q21 is the next stage switching transistor after switching transistor Q11. Compensation capacitor 6032 is connected in series between the drain D of switching transistor Q21 and the gate G of switching transistor Q31. Compensation capacitor 6033 is connected in series between the drain D of switching transistor Q31 and the gate G of switching transistor Q41. Compensation capacitor 6034 is connected in series between the drain D of switching transistor Q41 and the gate G of switching transistor Q51. Compensation capacitor 6035 is connected in series between the drain D of switching transistor Q51 and the gate G of switching transistor Q61 (not shown in the figure). Compensation capacitor 60316 is connected in series between the drain D of switching transistor Q161 and the gate G of switching transistor Q171. Figure 12 Taking a circuit with a total of 17 switching levels (N=17) as an example.

[0107] Figure 11 The solution shown addresses the uneven distribution of gate-drain capacitance in high-voltage scenarios. By connecting a compensation capacitor in series between the drain D of the first switching transistor in the first-stage switching circuit and the gate S of the first switching transistor in the second-stage switching circuit, a more uniform capacitance distribution can be achieved in the off-state of the RF switch, thereby improving the uniformity of voltage distribution.

[0108] like Figure 12 As shown, Figure 12 (a) shows an example where a compensation capacitor is connected across the input of the previous stage switch circuit and the gate of the next stage switch circuit in two adjacent switch circuits. Figure 12 (b) shows a scheme in the related art where a compensation capacitor is connected in series between the input terminal and the gate of each stage of the switching circuit, such as... Figure 12 Capacitors C1 to C17 are shown in (b). Figure 12 (c) shows a compensation scheme achieved by connecting a resistor in series between the input and output of each stage of the switching circuit, such as... Figure 12 Resistors R1 to R17 are shown in (c).

[0109] like Figure 13 for Figure 12 The simulation results of the capacitor compensation circuit shown in (a) are illustrated in Figure 1. Figure 14 for Figure 12 The simulation results of the capacitor compensation circuit shown in (b) are illustrated in the figure. Figure 15 for Figure 12 The simulation results of the capacitor compensation circuit shown in (c) are illustrated in the figure. Figures 13-15 (a) shows the maximum swing of each capacitor compensation circuit. Figures 13-15 (b) shows the insertion loss of each capacitor compensation circuit. Figures 13-15 (c) in the figure shows the isolation of each capacitor compensation circuit.

[0110] In the case of both having 17 cascaded switching circuits, compare Figures 13-15 As can be seen from Figure (a) of each figure... Figure 12 The capacitor compensation circuits shown in (a), (b), and (c) can all reduce the voltage of the maximum withstand voltage level (4.33V → 3.55V) through capacitor compensation. Figure 12 The capacitor compensation circuit shown in (a) requires four compensation capacitors for the first five stages of the switching circuit. The sizes of the four compensation capacitors are 290fF to 190fF to 80fF to 30fF, respectively. Figure 12 The capacitor compensation circuit shown in (b) requires five compensation capacitors for the first five switching stages. The sizes of the five compensation capacitors are 380fF~200fF~120fF~80fF~20fF respectively.

[0111] like Figure 13 As shown in (b) in the figure, Figure 12 The insertion loss of the circuit structure shown in (a) is 0.253–0.295 dB, as... Figure 13 As shown in (c) in the figure, Figure 12 The isolation of the circuit structure shown in (a) is -27.629 dB to -38.0399 dB; as Figure 14 As shown in (b) in the figure, Figure 12 The insertion loss of the circuit structure shown in (b) is 0.253–0.296 dB, as... Figure 14 As shown in (c) in the figure, Figure 12 The isolation of the circuit structure shown in (b) is -27.329 dB to -37.77 dB; as Figure 15 As shown in (b) in the figure, Figure 12 The insertion loss of the circuit structure shown in (c) is 0.253–0.294 dB, as... Figure 15 As shown in (c) in the figure, Figure 12 The isolation of the circuit structure shown in (c) is -28dB to -38.6dB; comparing the insertion loss of the three circuit structures, it can be seen that the isolation of this application is... Figure 12 The insertion loss ratio of the circuit structure shown in (a) is... Figure 12 The insertion loss shown in (b) is 1mdB better, and the benefit is more obvious in packages with low bump height. Furthermore, the isolation of the circuit structure shown in (a) of 12 in this application embodiment is better than that of the circuit structure shown in (b) of 12.

[0112] like Figure 16 As shown, Figure 16 It shows Figure 12 Comparison of layout simulation results for each structure in the diagram. Figure 16 (a) and (b) are Figure 12The layout simulation results of the capacitor compensation circuit shown in (a) are as follows; Figure 16 (c) and (d) in the text are Figure 12 The layout simulation results of the capacitor compensation circuit shown in (b) are shown in the figure. Figure 16 (e) and (f) in the text are Figure 12 The layout simulation results of the capacitor compensation circuit shown in (c) are shown below; where, Figure 12 The area of ​​the compensation capacitor in the capacitor compensation circuit shown in (a) is 1080 μm. 2 The total capacitance C_OFF in the off state is 82fF. Figure 12 The compensation capacitor area of ​​the capacitor compensation circuit shown in (b) is 1440 μm. 2 The total capacitance C_OFF in the off state is 84.4fF. Figure 12 The capacitor compensation circuit shown in (c) has a compensation capacitor area of ​​NA and a total capacitance C_OFF of 71.8fF in the off state.

[0113] By comparison, it can be seen that Figure 12 The compensation capacitor area of ​​the capacitor compensation circuit shown in (a) is lower than the total capacitance C_OFF in the off state, and the total capacitance is as follows: Figure 12 The circuit structure shown in (b) represents 73.75% of the capacitance value, and the low capacitance compensation results in a smaller degradation of C_OFF. Figure 12 The capacitor compensation circuit shown in (a) is compared to that shown in Figure 1. Figure 12 The capacitor compensation circuits shown in (b) and (c) have a total capacitance C_OFF value that is 2.4fF lower in the off state. The benefit of C_OFF is more obvious in scenarios with lower stage numbers. Moreover, the lower capacitance value of the compensation capacitor results in a smaller area of ​​the compensation capacitor, less parasitic to ground, and less impact on conduction insertion loss.

[0114] In another possible embodiment of this application, an embodiment of this application provides a radio frequency switch, which can adopt the above-described embodiments, for example... Figure 6 , Figure 7 or Figure 11 The capacitor compensation circuit described.

[0115] like Figure 17 and Figure 18 The figures shown are schematic diagrams illustrating application scenarios of the radio frequency switches provided in the embodiments of this application.

[0116] like Figure 17 As shown, the RF switch provided in this application embodiment can be applied to the RF front-end module of a wireless communication device, such as... Figure 17As shown, the RF front-end module includes an antenna 1401, an antenna feed line 1402, and one or more tuning circuits 1403. For example, one end of any tuning circuit 1403 is connected to the antenna 1401 or the antenna feed line 1402.

[0117] The other end of any tuning circuit 1403 is grounded.

[0118] For example, such as Figure 17 As shown, any tuning circuit 1403 may include one or more tuning branches, each tuning branch including a tuning load 14031 and an RF switch 14032. One end of the RF switch 14032 is connected to the antenna 1401 or the antenna feed line 1402, and the other end of the RF switch 14032 is connected to one end of the tuning load 14031. The other end of the tuning load 14031 is grounded.

[0119] For example, tuned load 14031 can refer to passive devices such as inductors.

[0120] It is worth noting that, Figure 17 Each RF switch 14032 in each tuning circuit 1403 can be implemented as described above, for example. Figure 6 , Figure 7 or Figure 11 The described capacitor compensation circuit balances the equivalent capacitance of the source-drain and gate-drain of each stage of the switching transistor, thereby achieving a uniform distribution of voltage swing and improving the voltage withstand capability of the switch.

[0121] like Figure 18 As shown, the RF switch provided in this application embodiment can be applied to the RF front-end module (FEM) of a wireless communication device, such as... Figure 18 As shown, the RF front-end module includes a TX switch 1501, an RX switch 1502, and an antenna port 1503. The TX switch 1501 includes a TX path serial transistor 15011 and a TX path parallel transistor 15012. The RX switch 1502 includes an RX path serial transistor 15021 and an RX path parallel transistor 15022.

[0122] The TX path parallel transistor 15012 is connected in series between the transmit port TX and ground; that is, one end of the TX path parallel transistor 15012 is connected to the transmit port TX, and the other end is grounded. The TX path switch 15011 is connected in series between the transmit port TX and the antenna; that is, one end of the TX path switch 15011 is connected to the transmit port TX, and the other end is connected to the antenna. The RX path serial transistor 15021 is connected in series between the antenna and the receive port TX; that is, one end of the RX path serial transistor 15021 is connected to the antenna, and the other end is connected to the receive port TX. The RX path parallel transistor 15022 is connected in series between the receive port TX and ground; that is, one end of the RX path parallel transistor 15022 is also connected to the other end of the RX path serial transistor 15021.

[0123] Among them, the TX path parallel transistor 15012 and the RX path serial transistor 15021 adopt the following... Figure 6 , Figure 7 or Figure 11 The described capacitor compensation circuit, namely the TX path parallel transistor 15012 and the RX path series transistor 15021, employs multi-stage inter-stage source-drain / gate-drain capacitor compensation to balance the equivalent capacitance of the source-drain and gate-drain of each stage die. This achieves a uniform distribution of voltage swing, improves the voltage withstand capability of the switch, and increases the power capacity of the TRX switch.

[0124] Optionally, the front-end module (FEM) can also connect to an RF chip. In addition to the aforementioned TX switch 1501 and RX switch 1502, the FEM may also include a gain unit (such as a power amplifier). In a transmission scenario, the TX path serial transistor 15011 is closed, the TX path parallel transistor 15012 is open, the RX path serial transistor 15021 is open, and the RX path parallel transistor 15022 is closed. Thus, the RF signal transmitted by the RF chip is amplified by the gain unit. Since the TX path serial transistor 15011 is closed, the amplified RF signal is transmitted to the antenna through the transmit port.

[0125] In another possible embodiment of this application, an embodiment of this application provides a radio frequency (RF) circuit, which includes an RF switch as described in the above embodiments. Specifically, the RF circuit may include an RF front-end module, which may include an RF switch. Specifically, the structure of the RF front-end module may be as follows: Figure 17 or Figure 18 As shown.

[0126] Optionally, the RF front-end module may also include RF chips and power amplifiers. The RF chip is used to transmit RF signals. The power amplifier is used to amplify the RF signals. When the RF switch is on, the RF signal can be transmitted to the antenna via the transmission channel.

[0127] In another possible embodiment of this application, this application provides a communication device that includes a radio frequency switch or radio frequency circuit as described in the above embodiments.

[0128] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video disc (DVD); or it can be a semiconductor medium, such as a solid-state drive (SSD).

[0129] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, the disclosure, and the appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple instances. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0130] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A capacitor compensation circuit, characterized in that, Applied in a switch, the switch having an input terminal and an output terminal, the capacitor compensation circuit includes: N cascaded switching circuits, wherein the output terminal of the previous stage of the N cascaded switching circuits is connected to the input terminal of the next stage of the switching circuit, the input terminal of the first stage of the N cascaded switching circuits is connected to the input terminal of the switch, and the output terminal of the last stage of the N cascaded switching circuits is connected to the output terminal of the switch, where N is greater than or equal to 2. At least one compensation capacitor, any one of which is connected across at least two stages of the switching circuit.

2. The capacitor compensation circuit according to claim 1, characterized in that, The first end of any of the compensation capacitors is connected to the input terminal of the i-th stage switching circuit, and the second end of any of the compensation capacitors is connected to the output terminal of the j-th stage switching circuit. The first ends of different compensation capacitors are connected to the input terminals of different switching circuits. i is an integer greater than or equal to 1 and less than or equal to N-1, and j is greater than or equal to i+1 and less than or equal to N.

3. The capacitor compensation circuit according to claim 1, characterized in that, The first end of any of the compensation capacitors is connected to the input or output of the i-th stage switching circuit, the second end of any of the compensation capacitors is connected to the gate control terminal of the j-th stage switching circuit, and the first ends of different compensation capacitors are connected to the input or output of different switching circuits. i is an integer greater than or equal to 1 and less than or equal to N-1, and j is greater than or equal to i+1 and less than or equal to N.

4. The capacitor compensation circuit according to claim 2 or 3, characterized in that, The j-th level switch circuit is the next level switch circuit after the i-th level switch circuit, or the j-th level switch circuit and the i-th level switch circuit are cascaded with at least one level switch circuit.

5. The capacitor compensation circuit according to any one of claims 1 to 4, characterized in that, The switching circuit includes: The first switching transistor and the second switching transistor; Wherein, the first terminal of the first switching transistor serves as the input terminal of the switching circuit, and is used to connect to the output terminal of the previous stage switching circuit or to the input terminal of the switch; The second terminal of the first switch transistor is connected to the first terminal of the second switch transistor and the second terminal of the second switch transistor, and serves as the gate control terminal of the switching circuit; The body terminal of the first switching transistor is connected to the third terminal of the second switching transistor; the third terminal of the first switching transistor serves as the output terminal of the switching circuit, used to connect to the input terminal of the next-stage switching circuit or the output terminal of the switch.

6. The capacitor compensation circuit according to claim 5, characterized in that, The first terminal is the drain, the third terminal is the source, and the second terminal is the gate; A first resistor is connected in series between the first terminal of the first switching transistor and the third terminal of the first switching transistor. The gate control terminal of any of the switching circuits is connected to one end of the second resistor, and the other end of the second resistor is connected to one end of the third resistor, the other end of which is used to receive a control signal.

7. A switch, characterized in that, The switch includes the capacitor compensation circuit described in any one of claims 1 to 6.

8. A radio frequency circuit, characterized in that, The radio frequency circuit includes: the switch as described in claim 7.

9. The radio frequency circuit according to claim 8, characterized in that, The radio frequency circuit further includes a transmitting port and a receiving port. Both the transmitting port and the receiving port are connected to an antenna. The transmitting port is connected to a first terminal of a first radio frequency switch, and a second terminal of the first radio frequency switch is connected to the antenna. The first terminal of the transmitting port is also grounded through a second radio frequency switch. The receiving port is connected to the antenna through a third radio frequency switch, and the receiving port is also grounded through a fourth radio frequency switch. The third radio frequency switch and the second radio frequency switch are the switches described in claim 7.

10. The radio frequency circuit according to claim 8, characterized in that, The radio frequency circuit further includes at least one tuning circuit connected to the antenna, each tuning circuit including one or more tuning branches, each tuning branch including a switch connected to the antenna and a load connected to the switch, the load being grounded, and each switch being a switch as described in claim 7.

11. A communication device, characterized in that, The communication device includes: a radio frequency front-end module, the radio frequency front-end module including the radio frequency circuit as described in any one of claims 8 to 10 or the switch as described in claim 7.

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