Radio frequency switch circuit for optimizing voltage distribution uniformity of stacked switch transistors, and chip

Abstract

Disclosed in the present invention are a radio frequency switch circuit for optimizing voltage distribution uniformity of stacked switch transistors, and a chip. The radio frequency switch circuit is formed by linking and stacking sources and drains of N switch transistors, wherein N is a positive integer, and N≥3; the source end and the drain end of each switch transistor are connected by means of a source-drain bias resistor; the bulk end of each switch transistor is connected to a bulk end bias resistor; when the N bulk end bias resistors are sequentially connected in series, the head end is connected to a bulk end bias voltage source; and series diode branches connected to the bulk ends of even-numbered stages of switch transistors are connected to the source ends and drain ends of respective switch transistors, and series diode branches connected to the bulk ends of odd-numbered stages of switch transistors are connected to the source ends and drain ends of respective adjacent switch transistors. When the radio frequency switch circuit is turned off, bulk end leakage currents generated by the stages of switch transistors flow into a radio frequency main path by means of the series diode branches and cancel each other out, thereby realizing the optimization of the voltage distribution uniformity of the stacked switch transistors.

Description

RF switch circuit and chip with optimized voltage distribution balance of stacked switch tubes Technical Field

[0001] The present invention relates to a radio frequency switching circuit for optimizing voltage distribution balance of stacked switching tubes, and also relates to a chip including the radio frequency switching circuit and corresponding electronic equipment, belonging to the technical field of radio frequency integrated circuits. Background Art

[0002] As one of the important components of the RF front-end module, the RF switching circuit is responsible for accurately switching the transmission path of the RF signal and selecting the corresponding RF path. In the case of a shared antenna in a wireless communication system, it can realize the reception and transmission of RF signals. It can also be used for antenna impedance tuning to improve antenna efficiency. In the existing technology, the RF switching circuit usually operates in high-voltage and high-power working scenarios and needs to withstand large voltage fluctuations. The method of improving the power and voltage resistance of the RF switching circuit generally adopts a stacked structure of switching transistors, that is, the RF switching circuit is formed by multiple stages of switching transistors connected in series. However, the voltage distribution in the RF switching circuit of this stacked structure is uneven, which generates a large number of harmonics, limiting the power and voltage resistance of the RF switching circuit. This affects the signal processing capability of the RF transceiver, resulting in a decrease in the communication quality of the communication system. In addition, when the RF switching circuit is used for antenna impedance tuning, it reduces the antenna efficiency. Summary of the Invention

[0003] The primary technical problem to be solved by the present invention is to provide a radio frequency switching circuit that optimizes the voltage distribution balance of stacked switching tubes.

[0004] Another technical problem to be solved by the present invention is to provide a chip including the radio frequency switching circuit and corresponding electronic equipment.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] According to a first aspect of an embodiment of the present invention, there is provided a radio frequency switch circuit for optimizing voltage distribution balance of stacked switch tubes, wherein the radio frequency switch circuit is composed of a stack of N switch transistors with source and drain links connected, where N is a positive integer and N≥3; wherein:

[0007] The source and drain of each switching transistor are connected via a source-drain bias resistor; the body of each switching transistor is connected to a body bias resistor, and after N body bias resistors are connected in series, the first end is connected to a body bias voltage source;

[0008] At the same time, the body terminal of the switching transistor of the first stage is connected to the drain terminal of the switching transistor of the second stage through one or two branches each consisting of X diodes connected in series in positive and negative directions;

[0009] The body terminals of the switching transistors in the middle even-numbered stages are respectively connected to the source terminal and the drain terminal of the respective switching transistors through a branch circuit composed of X or Y diodes connected in series; the body terminals of the switching transistors in the middle odd-numbered stages are respectively connected to the source terminal of the switching transistor in the previous stage and the drain terminal of the switching transistor in the next stage through a branch circuit composed of X diodes connected in series;

[0010] The body terminal of the switching transistor of the Nth stage is connected to the source terminal of the switching transistor of the N-1th stage through one or two branches each consisting of X diodes connected in series in positive and negative directions;

[0011] Wherein, X and Y are both positive integers, and X≥1, Y≤X; the positive ends of the branches formed by the positive and negative series connection of the diodes are both connected to the body terminal of the switching transistor.

[0012] Preferably, when the RF switch circuit is in the off state, when the source-drain voltage difference of the switching transistor reaches the conduction voltage of the series diode branch, the series diode branch becomes a low-resistance path after being turned on, and the body leakage current of the switching transistor flows through the low-resistance path to the source and drain ends of its own switching transistor or the source and drain ends of the adjacent switching transistor and then cancels each other out, thereby avoiding the deterioration of the performance of the RF switch circuit caused by the increase of the body-end bias voltage of the switching transistor and optimizing the balance of the voltage distribution of the stacked switch tubes.

[0013] Preferably, when the radio frequency switch circuit is in the on state, the voltages at both ends of the series diode branch are equal and short-circuited, thus being in an open circuit state.

[0014] Preferably, the gate terminal of each of the switching transistors is connected to a gate bias resistor, and after the N gate bias resistors are sequentially connected in series, the first end is connected to a gate bias voltage source.

[0015] Preferably, when the source-drain voltage difference of the switching transistor meets the conduction condition of the series diode branch at the body end of the odd-numbered switching transistor, but does not meet the conduction condition of the series diode branch at the body end of the even-numbered switching transistor, the series diode branch at the body end of the odd-numbered switching transistor is turned on first, and the body leakage current of the even-numbered switching transistor first flows through the first-level body series resistor and then through the series diode branch at the body end of the odd-numbered switching transistor to the source-drain node of the RF switching circuit transistor.

[0016] Preferably, when the source-drain voltage difference of the switching transistor simultaneously satisfies the conduction conditions of the series diode branches at the body ends of the odd-numbered switching transistors and the even-numbered switching transistors, the series diode branches at the body ends of the odd-numbered switching transistors and the even-numbered switching transistors are turned on at the same time, and the body end leakage current of the switching transistor flows to the source-drain node of the RF switching circuit transistor through a low-resistance path.

[0017] Preferably, in the series diode branch connected to the body terminal of the switching transistor, the number of diodes is determined according to the turn-on voltage of the series diode branch and the source-drain voltage difference of the switching transistor.

[0018] According to a second aspect of an embodiment of the present invention, an integrated circuit chip is provided, wherein the integrated circuit chip includes the radio frequency switch circuit for optimizing the voltage distribution balance of stacked switch tubes.

[0019] According to a third aspect of an embodiment of the present invention, an electronic device is provided, wherein the electronic device includes the radio frequency switch circuit for optimizing the voltage distribution balance of stacked switch tubes.

[0020] Compared to the prior art, the RF switching circuit for optimizing the voltage distribution balance of stacked switching tubes provided by the present invention achieves optimized voltage distribution balance of the stacked switching tubes by providing series diode branches at the body terminals of each switching transistor. This technical solution directs the leakage current generated by the body terminals of each switching transistor into the main RF path and offsets the leakage current. This optimizes the voltage distribution balance of the stacked switching tubes, further improving the linearity and power handling capability of the RF switching circuit. Therefore, the RF switching circuit for optimizing the voltage distribution balance of the stacked switching tubes provided by the present invention has the advantages of a clever and reasonable structural design, low design cost, and excellent circuit performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG1 is a circuit diagram of a typical radio frequency switching circuit in the prior art;

[0022] FIG2 is a circuit schematic diagram of a radio frequency switch circuit for optimizing voltage distribution balance of stacked switch tubes provided by an embodiment of the present invention;

[0023] FIG3 is a comparison diagram of second-order harmonic simulation measurements of the radio frequency switch circuit according to the prior art solution and the technical solution of the present invention in an embodiment of the present invention;

[0024] FIG4 is a comparison diagram of third-order harmonic simulation measurements of the radio frequency switch circuit according to the prior art solution and the technical solution of the present invention in an embodiment of the present invention;

[0025] FIG5 is a comparison diagram of the simulated measurement of the source-drain voltage of the radio frequency switch circuit according to the prior art solution and the technical solution of the present invention in an embodiment of the present invention;

[0026] FIG6 is a schematic diagram of an electronic device using the radio frequency switching circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The technical content of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] To facilitate understanding and explanation, the following first briefly introduces the radio frequency switch circuit in the existing technical solution, and then describes in detail the specific technical solution of the embodiment of the present invention on this basis.

[0029] A typical RF switch circuit in the prior art is shown in FIG1 . The RF switch circuit is composed of N (N is a positive integer and N≥3) switching transistors M1 to M2. N The source and drain terminals of each switching transistor are connected through a source-drain bias resistor Rds; the gate terminal of each switching transistor is connected to a gate bias resistor R G Connect N gate bias resistors R G After being connected in series, the first terminal GC is connected to the gate bias voltage source Vg; the body terminal of each switching transistor is connected to a body bias resistor R B Connect the N-terminal bias resistor R B After being connected in series in sequence, the first end BC is connected to the body bias voltage source Vb.

[0030] Typically, when the RF switch circuit is on, the gate bias voltage Vg is 2.5V and the body bias voltage Vb is 0V. When the RF switch circuit is off, the gate bias voltage Vg is -2.5V and the body bias voltage Vb is -2.5V. The on and off states of the RF switch circuit are controlled by changing the voltage values ​​of the gate bias voltage Vg and the body bias voltage Vb. The source-drain bias resistor Rds provides a DC off potential for the off-state switching transistor, preventing charge accumulation on the source-drain node of the switching transistor, which could cause premature breakdown of the switching transistor.

[0031] Due to the structure of the switching transistors themselves, each switching transistor has a parasitic diode between its body terminal and its source and drain terminals. For example, in Figure 1, a parasitic diode Dbs1 exists between the body terminal B1 and the source terminal S1 of the first-stage switching transistor M1, and a parasitic diode Dbd1 exists between the body terminal B1 and the drain terminal D1. When the RF switch circuit is in the on state, each switching transistor short-circuits its own parasitic diode. In other words, the presence of the parasitic diode has no effect on the on-resistance of the RF switch circuit path in the on state.

[0032] When the RF switch circuit is in the off state, especially the RF switch circuit used for antenna impedance tuning is usually in the judgment state, a voltage difference will appear between the source and drain terminals of the stacked link structure switch transistor, and the higher the power value of the RF signal, the greater the voltage difference will be. When the voltage difference increases to a certain extent, the parasitic diode between the body terminal and the source terminal or between the body terminal and the drain terminal is turned on, thereby generating a body leakage current iB. The body leakage current iB will be generated at the body bias resistor R B A voltage drop is generated on the body, thereby raising the body bias voltage. The degree to which the body bias voltage is raised is closely related to the number of series-connected switching transistors. When the number of series-connected switching transistors is greater, the body bias resistor R B The greater the total body leakage current, the greater the increase in the body bias voltage. This increase in the body bias voltage of the switching transistor causes the RF switching circuit to rapidly generate a large number of harmonics, making nonlinearity more pronounced. This also exacerbates the voltage imbalance in the stacked link structure's switching transistors, making them more susceptible to breakdown and significantly reducing the power handling capacity of the RF switching circuit.

[0033] In order to solve the above problems existing in the prior art, an embodiment of the present invention provides a radio frequency switch circuit that optimizes the voltage distribution balance of stacked switch tubes. As shown in FIG2 , the radio frequency switch circuit comprises N (N is a positive integer and N ≥ 3) switching transistors M1 to M2. N The source and drain terminals of each switching transistor are connected through a source-drain bias resistor Rds; the gate terminal of each switching transistor is connected to a gate bias resistor R G Connect N gate bias resistors R G After being connected in series, the first terminal GC is connected to the gate bias voltage source Vg; the body terminal of each switching transistor is connected to a body bias resistor R B Connect the N-terminal bias resistor R B After being connected in series, the first terminal BC is connected to the body-side bias voltage source Vb. Simultaneously, the body of the first-stage switching transistor is connected to the drain of the second-stage switching transistor via two branches, each consisting of X (X is a positive integer, and X ≥ 1) diodes connected in series. The body of the intermediate even-numbered switching transistors is connected to the source and drain of each switching transistor via a branch consisting of X diodes connected in series. The body of the intermediate odd-numbered switching transistors is connected to the source of the previous-stage switching transistor and the drain of the next-stage switching transistor via a branch consisting of X diodes connected in series. The body of the Nth-stage (final-stage) switching transistor is connected to the source of the N-1th-stage switching transistor via two branches, each consisting of X diodes connected in series. The positive ends of the branches consisting of X diodes connected in series are connected to the body of the switching transistor.

[0034] When the RF switch circuit is in the on state, due to the source voltage V S and drain voltage V D are the same, the body voltage V B =(V S +V D ) / 2+Vb, where the body-side bias voltage Vb is 0 volts, so the body-side voltage is the same as the source-drain voltage. Therefore, each branch consisting of X diodes connected in series is effectively short-circuited, in an open-circuit state, and has no effect on the on-resistance of the RF signal path.

[0035] When the RF switch circuit is in the off state, when the source-drain voltage difference of the switching transistor of the stacked link structure reaches the conduction voltage of the series diode branch, the branch composed of the positive and negative series connection of X diodes is in the on state, compared with the bias resistor R B The bias network formed by the positive and negative series connection of the diodes is a low-resistance path. Therefore, due to the increase in the voltage difference between the source and drain terminals of the switching transistor, the parasitic diode between the body terminal and the source terminal or between the body terminal and the drain terminal is turned on, resulting in the body leakage current iB, which no longer flows through the body bias resistor R B Instead of forming a bias network, the diodes flow through the branch formed by the series connection of the positive and negative diodes to the source and drain of their own switching transistors or the source and drain of adjacent switching transistors. Furthermore, the leakage currents iB at each body end cancel each other out after flowing through the bias resistor Rds between the source and drain terminals. Therefore, the performance of the RF switch circuit, which would otherwise be degraded by an increased body-end bias voltage, is eliminated. The voltage distribution of the stacked switches is balanced, and the generation of large amounts of harmonics is avoided. This improves the linearity of the RF switch circuit and significantly enhances its power handling capability.

[0036] When the source-drain voltage difference of the switching transistor is small, that is, the voltage difference satisfies the conduction condition of the series diode branch at the body end of the odd-numbered switching transistor, but does not satisfy the conduction condition of the series diode branch at the body end of the even-numbered switching transistor, the series diode branch at the body end of the odd-numbered switching transistor is turned on first, and the leakage current at the body end of the even-numbered switching transistor first passes through the first-stage body end series resistor R B Then it flows to the source and drain nodes of the RF switch circuit transistor through the series diode branch at the body end of the odd-numbered switching transistor.

[0037] When the source-drain voltage difference of the switching transistor is large, that is, when the voltage difference satisfies the conduction condition of the series diode branches at the body ends of the odd-numbered switching transistor and the even-numbered switching transistor at the same time, the series diode branches at the body ends of the odd-numbered switching transistor and the even-numbered switching transistor are turned on at the same time, and the series diode branches at the body ends of the even-numbered switching transistor add an additional leakage path. The leakage current at the body end of the odd-numbered switching transistor can also be discharged through the first-level body end series resistor R B The current flows through the series diode branch at the body end of the even-numbered switching transistor and further flows to the source-drain node of the RF switching circuit transistor, thereby preventing the series diode branch of the odd-numbered switching transistor from being broken down.

[0038] In one embodiment of the present invention, the body terminals of the first-stage switching transistor and the body terminals of the N-stage (final-stage) switching transistor of the radio frequency switching circuit are both connected to the drain terminals or source terminals of adjacent switching transistors via two branches each consisting of X diodes connected in series. In other embodiments of the present invention, the body terminals of the first-stage switching transistor and the body terminals of the N-stage (final-stage) switching transistor of the radio frequency switching circuit may also be connected to the drain terminals or source terminals of adjacent switching transistors via a branch consisting of X diodes connected in series, without affecting the optimized performance of the circuit.

[0039] In one embodiment of the present invention, in a radio frequency switching circuit, the series diode branches connected to the body terminals of odd-numbered switching transistors and the series diode branches connected to the body terminals of even-numbered switching transistors are each composed of X diodes connected in series. In other embodiments of the present invention, depending on the needs of the radio frequency circuit, a technical solution can be adopted in which the series diode branches connected to the body terminals of odd-numbered switching transistors are composed of X diodes connected in series, and the series diode branches connected to the body terminals of even-numbered switching transistors are composed of Y diodes connected in series, where Y is a positive integer and Y≤X.

[0040] It should be noted that in a branch consisting of X diodes connected in series, the number X of diodes is usually determined by the on-state voltage of the branch consisting of the X diodes connected in series and the source-drain voltage difference of the switching transistor.

[0041] In the radio frequency switch circuit using the existing technical solution, when the number of series switch transistors increases, the current flowing through the body terminal bias resistor R B The greater the total body leakage current, the greater the degree to which the body bias voltage is raised, and the more obvious the nonlinearity of the RF switch circuit. The technical effect achieved by the embodiment of the present invention is exactly the opposite. In the embodiment of the present invention, the RF switch circuit composed of N switching transistors with source and drain links stacked together, when the number N of switching transistors is larger, the performance of optimizing the voltage distribution balance and linearization of the stacked switching tubes is more obvious, and the power handling capacity is improved more significantly.

[0042] In order to verify the excellent performance of the RF switching circuit for optimizing the voltage distribution balance of stacked switching tubes provided by an embodiment of the present invention, the inventors conducted multiple simulation comparison tests on the RF switching circuit and the RF switching circuit using the existing technical solution. The test results are shown in Figures 3, 4 and 5.

[0043] Figure 3 is a second-order harmonic simulation test curve of the RF switching circuit, with the horizontal axis representing input power and the vertical axis representing second-order harmonics, both in dBm. As can be seen from Figure 3, when the input power is low, the second-order harmonics generated by the RF switching circuit provided by the embodiment of the present invention and the RF switching circuit using the prior art solution are substantially the same. However, as the input power increases, the second-order harmonics generated by the RF switching circuit provided by the embodiment of the present invention are significantly smaller than those generated by the RF switching circuit using the prior art solution, and the second-order harmonic performance is significantly optimized.

[0044] Figure 4 is a third-order harmonic simulation test curve of the RF switching circuit, with the horizontal axis representing input power and the vertical axis representing third-order harmonics, both in dBm. As can be seen from Figure 4, when the input power is low, the third-order harmonics generated by the RF switching circuit provided by the embodiment of the present invention and the RF switching circuit using the prior art solution are substantially the same. However, as the input power increases, the third-order harmonics generated by the RF switching circuit provided by the embodiment of the present invention are significantly smaller than those generated by the RF switching circuit using the prior art solution, and the third-order harmonic performance is significantly optimized.

[0045] Figure 5 shows the simulation test results of the source-drain voltage of the RF switch circuit. The test circuit is a RF switch circuit with 24 switch transistors stacked and linked, and the test input power is 48dBm. In Figure 5, the horizontal axis is the switch transistors at each level (from the 1st to the 24th level), and the vertical axis is the actual voltage value of the source-drain voltage Vds of the switch transistor, in volts (V). As can be seen from Figure 5, the RF switch circuit provided by the embodiment of the present invention is compared with the RF switch circuit using the existing technology solution. In the RF switch circuit using the existing technology solution, the source-drain voltage Vds of the switch transistors at each level has a large difference, and the maximum difference of Vds is about 0.35V; while in the RF switch circuit provided by the embodiment of the present invention, the source-drain voltage Vds of the switch transistors at each level is relatively balanced, and the maximum difference of Vds is only about 0.05V. It shows that the RF switch circuit provided by the embodiment of the present invention can well optimize the balance of the voltage distribution of the stacked switch tubes, avoid the generation of a large number of harmonics, and thereby achieve improved linearization and improved power handling capacity.

[0046] The above describes in detail the structure and working principle of the RF switch circuit for optimizing the voltage distribution balance of stacked switch tubes provided by the present invention. Based on the RF switch circuit, an embodiment of the present invention further provides an integrated circuit chip, which includes the above-mentioned RF switch circuit for optimizing the voltage distribution balance of stacked switch tubes, and is used as an important component of the RF front-end module in a wireless communication system. Its function is to accurately switch the transmission path of the RF signal and select the corresponding RF path; or, in the case of a shared antenna in the wireless communication system, it can realize the reception and transmission of RF signals; it can also be used for antenna impedance tuning to improve antenna efficiency. The specific structure of the RF switch circuit for optimizing the voltage distribution balance of stacked switch tubes in the integrated circuit chip will not be described in detail here.

[0047] In addition, the RF switch circuit for optimizing the voltage distribution balance of stacked switch tubes provided by the present invention can be used in electronic devices as an important component of communication components. The electronic equipment mentioned here refers to computer equipment that can be used in a mobile environment and supports multiple communication standards such as GSM, EDGE, CDMA, TD_SCDMA, WCDMA, TDD_LTE, FDD_LTE, NR, etc., including mobile phones, laptops, tablets, car computers, etc. In addition, the technical solution provided by the present invention is also applicable to other applications of RF integrated circuits, such as communication base stations, smart connected cars, etc.

[0048] As shown in Figure 6, the electronic device includes at least a processor, a memory and a communication component, and may further include a sensor component, a power component, a multimedia component and an input / output interface according to actual needs. Among them, the memory, communication component, sensor component, power component, multimedia component and input / output interface are all connected to the processor. The memory can be a static random access memory (SRAM), an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a programmable read-only memory (PROM), a read-only memory (ROM), a magnetic memory, a flash memory, etc., and the processor can be a central processing unit (CPU), a graphics processing unit (GPU), a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a digital signal processing (DSP) chip, etc. Other communication components, sensor components, power components, multimedia components, etc. can all be implemented using general components and are not specifically described here.

[0049] In summary, compared with the prior art, the RF switching circuit for optimizing the voltage distribution balance of stacked switching tubes provided by the present invention optimizes the voltage distribution balance of stacked switching tubes by providing series diode branches at the body terminals of each switching transistor, thereby introducing the body leakage current generated by each switching transistor into the main RF path and offsetting each other. This technical solution achieves optimization of the voltage distribution balance of stacked switching tubes, further improving the linearity and power handling capability of the RF switching circuit. Therefore, the RF switching circuit for optimizing the voltage distribution balance of stacked switching tubes provided by the present invention has the beneficial effects of ingenious and reasonable structural design, low design cost, and excellent circuit performance.

[0050] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0051] The above describes in detail the RF switch circuit and chip for optimizing the voltage distribution balance of stacked switches provided by the present invention. For those skilled in the art, any obvious modification to this invention without departing from its essence would constitute an infringement of the present invention's patent rights and would incur corresponding legal liability.

Claims

1. A radio frequency switch circuit for optimizing the voltage distribution balance of stacked switching transistors, characterized in that The RF switch circuit is composed of N switch transistors with their source-drain terminals connected in series and stacked, where N is a positive integer and N≥3; among them, the source terminal and the drain terminal of each of the switch transistors are connected through a source-drain bias resistor; the body terminal of each of the switch transistors is connected to a body terminal bias resistor, and after the N body terminal bias resistors are connected in series in sequence, the head end is connected to a body terminal bias voltage source; meanwhile, the body terminal of the first-stage switch transistor is connected to the drain terminal of the second-stage switch transistor through one or two branches each composed of X diodes connected in series with positive and negative polarities; the body terminals of the switch transistors at the intermediate even levels are respectively connected to the source terminal and the drain terminal of their own switch transistors through a branch composed of X or Y diodes connected in series with positive and negative polarities; the body terminals of the switch transistors at the intermediate odd levels are respectively connected to the source terminal of the previous-stage switch transistor and the drain terminal of the next-stage switch transistor through a branch composed of X diodes connected in series with positive and negative polarities; the body terminal of the Nth-stage switch transistor is connected to the source terminal of the (N-1)th-stage switch transistor through one or two branches each composed of X diodes connected in series with positive and negative polarities; wherein, both X and Y are positive integers, and X≥1, Y≤X; the positive ends of the branches composed of diodes connected in series with positive and negative polarities are all connected to the body terminals of the switch transistors.

2. The RF switch circuit for optimizing the voltage distribution balance of stacked switch transistors according to claim 1, wherein: when the RF switch circuit is in the off state, when the voltage difference between the source and drain terminals of the switch transistor reaches the conduction voltage of the series diode branch, after the series diode branch conducts, it becomes a low-resistance path, and the body terminal leakage current of the switch transistor flows through this low-resistance path to the source terminal and the drain terminal of its own switch transistor or the source terminal and the drain terminal of the adjacent switch transistor and then cancels each other out.

3. The RF switch circuit for optimizing the voltage distribution balance of stacked switch transistors according to claim 1, wherein: when the RF switch circuit is in the on state, the voltages at both ends of the series diode branch are equal and it is short-circuited and in an open state.

4. The RF switch circuit for optimizing the voltage distribution balance of stacked switch transistors according to claim 2 or 3, wherein: the gate terminal of each of the switch transistors is connected to a gate terminal bias resistor, and after the N gate terminal bias resistors are connected in series in sequence, the head end is connected to a gate terminal bias voltage source.

5. The RF switch circuit for optimizing the voltage distribution balance of stacked switch transistors according to claim 1, wherein: when the source-drain voltage difference of the switch transistor satisfies the conduction condition of the series diode branch at the body terminal of the odd-level switch transistor but does not satisfy the conduction condition of the series diode branch at the body terminal of the even-level switch transistor, the series diode branch at the body terminal of the odd-level switch transistor conducts first, and the body terminal leakage current of the even-level switch transistor first flows through a body terminal series resistor and then through the series diode branch at the body terminal of the odd-level switch transistor to the source-drain node of the RF switch circuit transistor.

6. The RF switch circuit for optimizing the voltage distribution balance of stacked switch transistors according to claim 1, wherein: When the source-drain voltage difference of the switching transistor simultaneously satisfies the conduction conditions of the series diode branches at the body terminals of the switching transistors in the odd levels and the switching transistors in the even levels, the series diode branches at the body terminals of the switching transistors in the odd levels and the switching transistors in the even levels conduct simultaneously, and the body terminal leakage current of the switching transistor flows to the source-drain node of the radio frequency switch circuit transistor through a low-resistance path.

7. The radio frequency switch circuit for optimizing the voltage distribution balance of the stacked switching transistors according to claim 1, wherein: In the series diode branch connected to the body terminal of the switching transistor, the number of the diodes is determined according to the conduction voltage of the series diode branch and the source-drain voltage difference of the switching transistor.

8. A radio frequency switch circuit for optimizing the voltage distribution balance of stacked switching transistors, characterized in that The radio frequency switch circuit is formed by stacking N source-drain connections of switching transistors, where N is a positive integer and N≥3; among them, The source terminal and the drain terminal of each switching transistor are connected through a source-drain bias resistor; the body terminal of each switching transistor is connected to a body terminal bias resistor, and after the N body terminal bias resistors are connected in series in sequence, the first end is connected to the body terminal bias voltage source; At the same time, the body terminal of the switching transistor in the first level is connected to the drain terminal of the switching transistor in the second level through one or two branches each formed by connecting X diodes in series with positive and negative polarities; The body terminals of the switching transistors in the intermediate even levels are respectively connected to the source terminal and the drain terminal of their respective switching transistors through a branch formed by connecting X diodes in series with positive and negative polarities; or, through a branch formed by connecting Y diodes in series with positive and negative polarities to the source terminal and the drain terminal of their respective switching transistors; The body terminals of the switching transistors in the intermediate odd levels are respectively connected to the source terminal of the previous-level switching transistor and the drain terminal of the next-level switching transistor through a branch formed by connecting X diodes in series with positive and negative polarities; The body terminal of the switching transistor in the Nth level is connected to the source terminal of the switching transistor in the (N−1)th level through one or two branches each formed by connecting X diodes in series with positive and negative polarities; Both X and Y are positive integers, and X≥1, Y≤X; the positive ends of the branches formed by connecting the diodes in series with positive and negative polarities are all connected to the body terminals of the switching transistors; among them, when the radio frequency switch circuit is in the off state: When the source-drain voltage difference of the switching transistor only satisfies the conduction conditions of the series diode branches at the body terminals of the switching transistors in the odd levels, the series diode branches at the body terminals of the switching transistors in the odd levels conduct, and the body terminal leakage current of the switching transistors in the even levels first passes through the body terminal bias resistor and then through the series diode branches at the body terminals of the switching transistors in the odd levels and flows to the source-drain node of the switching transistor; When the source-drain voltage difference of the switching transistor simultaneously satisfies the conduction conditions of the series diode branches at the body terminals of the switching transistors in the odd levels and the switching transistors in the even levels, each series diode branch conducts simultaneously, and the body terminal leakage current of each switching transistor flows to the source-drain node of the switching transistor through a low-resistance path; Each body terminal leakage current cancels each other out after flowing through the source-drain bias resistor.

9. An integrated circuit chip, characterized in that Including the radio frequency switch circuit for optimizing the voltage distribution balance of the stacked switching transistors according to any one of claims 1 to 8.

10. An electronic device, characterized in that The radio frequency switch circuit for optimizing the voltage distribution balance of stacked switching tubes according to any one of claims 1 to 8.

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