Radio frequency switch circuit, radio frequency module and antenna tuner

Abstract

The invention provides a radio frequency switch circuit, a radio frequency module and an antenna tuner, the radio frequency switch circuit comprises a first voltage division branch, a second voltage division branch and a switch branch, the first voltage division branch and the second voltage division branch each comprise a switch unit and a switch bias unit; the switch branch comprises N first transistors which are connected in series, the body electrode of the mth first transistor is connected with the source electrode of the ith first transistor through the switch unit in the first voltage division branch, and the body electrode of the mth first transistor is connected with the drain electrode of the jth first transistor through the switch unit in the second voltage division branch; n, m, i and j meet the following relations: 1 < m < N, 0 < i < m, m < j < = N, and N > = 3; the switch bias unit can be used for intermittently providing a bias signal for the switch unit, so that the switch unit is intermittently switched on. According to the radio frequency switch circuit, voltage division can be achieved on the first transistors connected in series, and the voltage-resistant performance of the radio frequency switch circuit is improved.

Description

Technical Field

[0001] The present application relates to the field of radio frequency technology, and in particular to a radio frequency switching circuit, a radio frequency module and an antenna tuner. Background Art

[0002] In the field of communication technology, the RF switching circuit is one of the important components of the RF front-end module. Its function is to accurately switch the transmission path of the RF signal and select the corresponding RF path. When the wireless communication system shares the antenna, the reception and transmission of RF signals can be realized.

[0003] In related technologies, RF switching circuits usually need to work in high-voltage and high-power working scenarios and need to withstand large voltage fluctuations. Generally, RF switching circuits use multiple transistor stacking methods to improve the voltage resistance of RF switching circuits, but this stacking method easily leads to uneven transistor voltage division, causing some transistors to withstand larger voltages, which in turn leads to lower overall voltage tolerance of the RF switch. Summary of the invention

[0004] The present application provides a radio frequency switching circuit, a radio frequency module and an antenna tuner, aiming to improve the uniformity of voltage distribution of the radio frequency switching circuit.

[0005] In a first aspect, the present application provides a radio frequency switch circuit, the radio frequency switch circuit comprising:

[0006] a first connection end and a second connection end;

[0007] A voltage-dividing branch, wherein the voltage-dividing branch comprises a first voltage-dividing branch and a second voltage-dividing branch, wherein the first voltage-dividing branch and the second voltage-dividing branch both comprise a switch unit and a switch bias unit;

[0008] A switch branch, wherein the switch branch comprises N first transistors connected in series between the first connection terminal and the second connection terminal, the body of the mth first transistor is connected to the source of the ith first transistor through the switch unit in the first voltage dividing branch, and the body of the mth first transistor is connected to the drain of the jth first transistor through the switch unit in the second voltage dividing branch, wherein N, m, i and j are all positive integers and satisfy the following relationship: 1<m<N, 0<i<m, m<j≤N, N≥3;

[0009] Wherein, when the first transistor is turned off, the switch bias unit is used to intermittently provide a bias signal to the switch unit so that the switch unit is intermittently turned on.

[0010] In a second aspect, the present application further provides a radio frequency module, which includes a radio frequency switching circuit as provided in the first aspect.

[0011] In a third aspect, the present application further provides an antenna tuner, comprising a plurality of parallel tuning branches, each tuning branch comprising a tuning component and a radio frequency switching circuit as provided in the first aspect, the radio frequency switching circuit being connected in series with the tuning component.

[0012] The present application provides a radio frequency switching circuit, a radio frequency module and an antenna tuner. The present application connects the body of the mth first transistor to the source of the ith first transistor through the switch unit of the first voltage-dividing branch, and connects the body of the mth first transistor to the drain of the jth first transistor through the switch unit in the second voltage-dividing branch, so that when the first transistor is turned off, the switch bias unit in the first voltage-dividing branch and the second voltage-dividing branch can intermittently provide a bias signal to the switch unit, so that the switch unit is indirectly turned on, thereby realizing voltage division of the first transistor, making the voltage division of multiple first transistors in the radio frequency switching circuit more uniform, solving the problem of uneven voltage division caused by the transistor stacking setting method, and improving the voltage resistance of the radio frequency switching circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 A schematic diagram of the structure of a radio frequency switch circuit provided in one embodiment of the present application;

[0015] Figure 2 A schematic diagram of a radio frequency switch circuit provided in an embodiment of the present application;

[0016] Figure 3a A schematic diagram of the structure of a voltage dividing branch provided in an embodiment of the present application;

[0017] Figure 3b A schematic diagram of the structure of a voltage dividing branch provided in another embodiment of the present application;

[0018] Figure 3c A schematic diagram of the structure of a voltage dividing branch provided in yet another embodiment of the present application;

[0019] Figure 3d A schematic diagram of the structure of a voltage dividing branch provided in yet another embodiment of the present application;

[0020] Figure 4a A schematic diagram of the structure of a switch bias unit provided in an embodiment of the present application;

[0021] Figure 4bA schematic diagram of the structure of a switch bias unit provided in another embodiment of the present application;

[0022] Figure 4c A schematic structural diagram of a switch bias unit provided in yet another embodiment of the present application;

[0023] Figure 5 A schematic diagram of the structure of a voltage dividing branch provided in another embodiment of the present application;

[0024] Figure 6a A schematic diagram of the structure of a switch bias unit provided in an embodiment of the present application;

[0025] Figure 6b A schematic diagram of the structure of a switch bias unit provided in another embodiment of the present application;

[0026] Figure 6c A schematic structural diagram of a switch bias unit provided in yet another embodiment of the present application;

[0027] Figure 6d A schematic diagram of the structure of a switch bias unit provided in yet another embodiment of the present application;

[0028] Figure 7 A schematic diagram of a radio frequency module provided in one embodiment of the present application;

[0029] Figure 8 A schematic diagram of an antenna tuner provided in accordance with an embodiment of the present application.

[0030] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0033] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0034] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a radio frequency switch circuit provided in one embodiment of the present application.

[0035] like Figure 1 As shown, the radio frequency switch circuit includes a first connection terminal 11, a second connection terminal 12, a voltage dividing branch and a switch branch 13. Specifically, the voltage dividing branch includes a first voltage dividing branch 141 and a second voltage dividing branch 142, and the first voltage dividing branch 141 includes a switch unit 1411 and a switch bias unit 1412, and the second voltage dividing branch 142 includes a switch unit 1421 and a switch bias unit 1422; the switch branch 13 includes N first transistors connected in series between a first connection terminal 11 of the radio frequency switch circuit and a second connection terminal 12 of the radio frequency switch circuit, the body of the mth first transistor Qm is connected to the source of the ith first transistor Qi through the switch unit 1411 in the first voltage dividing branch 141, and the body of the mth first transistor Qm is connected to the drain of the jth first transistor Qj through the switch unit 1421 in the second voltage dividing branch 142, wherein N, m, i and j are all positive integers and satisfy the following relationship: 1<m<N, 0<i<m, m<j≤N, N≥3.

[0036] It should be noted that, in the related art, the RF switching circuit connects multiple transistors in series between the first connection terminal 11 and the second connection terminal 12 of the RF switching circuit to form a stacking structure, thereby improving the voltage resistance of the RF switching circuit. However, in the above-mentioned setting method, when the first transistor is turned off, there is a large voltage difference between the first connection terminal 11 and the second connection terminal 12, and the voltage difference is distributed on the above-mentioned N first transistors stacked on each other. The voltage difference between the source and drain terminals of different transistors in the stacking structure is inconsistent, that is, the voltage distribution of the RF switching circuit is uneven, resulting in different voltages borne by each transistor in the RF switching circuit, which reduces the power tolerance of the entire RF switching circuit.

[0037] It should be understood that in the embodiment of the present application, when the first transistor is turned off, the voltage difference between different first transistors enables the switch bias unit 1412 in the first voltage dividing branch 141 to intermittently provide a bias signal to the switch unit 1411 so that the switch unit 1411 is intermittently turned on; the switch bias unit 1422 in the second voltage dividing branch 142 is able to intermittently provide a bias signal to the switch unit 1421 so that the switch unit 1421 is intermittently turned on.

[0038] It can be understood that when all the first transistors are turned on, since the on-resistance of the first transistors is very small, the voltage difference between the first connection terminal 11 and the second connection terminal 12 is almost zero, so the switch units in the first voltage divider branch 141 and the second voltage divider branch 142 will not be turned on, thereby not affecting the transmission of the RF signal between the first connection terminal 11 and the second connection terminal 12.

[0039] In the present application, a first transistor in a radio frequency switch circuit is connected to another first transistor through a first voltage-dividing branch 141 and / or a second voltage-dividing branch 142, and when the first transistor is turned off, the switch bias unit 1412 in the first voltage-dividing branch 141 can intermittently provide a bias signal to the switch unit 1411, so that the switch unit 1411 is intermittently turned on, and the second voltage-dividing branch 142 can intermittently provide a bias signal to the switch unit 1421, so that the switch unit 1422 is intermittently turned on, so that the current can flow from the source of the i-th first transistor Qi to the body of the m-th first transistor Qm and from the body of the m-th first transistor Qm to the drain of the j-th first transistor Qj through the turned-on switch units 1411 and 1421, thereby making the voltage distribution to which each first transistor is subjected more uniformly, so as to solve the problem that some transistors in the radio frequency switch circuit are subjected to a large voltage.

[0040] It should be noted that Figure 1 Only the complete connection method of the mth first transistor Qm is shown, and the complete connection of the ith first transistor Qi and the jth first transistor Qj is not shown. It should be understood that the specific connection method of the ith first transistor Qi and the jth first transistor Qj can refer to the connection method of the mth first transistor Qm, so as to realize voltage division of multiple first transistors.

[0041] In some embodiments, when the RF signal is transmitted between the first connection terminal 11 and the second connection terminal 12 of the switch branch 13 , it passes through the i-th first transistor Qi, the m-th first transistor Qm and the j-th first transistor Qj in sequence.

[0042] Exemplarily, the i-th first transistor Qi, the m-th first transistor Qm, and the j-th first transistor Qj are sequentially connected in series in the switch branch 13 along the propagation direction of the RF signal in the switch branch 13 to improve the voltage withstand capability of the RF switch circuit. It should be understood that the i-th first transistor Qi, the m-th first transistor Qm, and the j-th first transistor Qj are for illustration only, and more first transistors may be connected in series in the switch branch 13, which is not limited in the present application.

[0043] like Figure 2 As shown, Figure 2 A schematic diagram of a radio frequency switch circuit provided in accordance with an embodiment of the present application.

[0044] In some embodiments, the body of the 1st first transistor Q1 is connected to the drain of the xth first transistor Qx through the second voltage divider branch 142; the body of the Nth first transistor QN is connected to the source of the yth first transistor Qy through the first voltage divider branch 141, where x and y are both positive integers and satisfy the following relationship: 1<x≤5, N-4≤y<N.

[0045] Exemplarily, the first first transistor Q1 indicates a first transistor adjacent to the first connection terminal 11 of the radio frequency switch circuit, and the Nth first transistor QN is a first transistor adjacent to the second connection terminal 12 of the radio frequency switch circuit. Since there is no first transistor that is earlier than the first first transistor Q1, the body of the first transistor is connected to the drain of the xth first transistor Qx through the second voltage divider branch 142, wherein the xth first transistor Qx is a first transistor that is later than the first first transistor Q1, and is less than or equal to 4 first transistors away from the first first transistor Q1. The first transistor is connected to the source of the yth first transistor Qy through the first voltage dividing branch 141, and the number of first transistors between the yth first transistor Qy and the Nth first transistor QN is also less than or equal to 4, so as to ensure the voltage dividing effect of the first voltage dividing branch 141.

[0046] In some embodiments, m, i and j also satisfy the following relationship: mi≤4, jm≤4.

[0047] Exemplarily, since the current leaked from the body of the first transistor is small, if the two first transistors connected by the voltage divider branch are separated by more first transistors, the voltage dividing effect of the voltage divider branch will be reduced. Therefore, the number of first transistors between the two first transistors connected by the first voltage divider branch 141 and / or the second voltage divider branch 142 is set to be no more than 4 to ensure the voltage dividing effect of the voltage divider branch, thereby improving the overall voltage resistance of the RF switching circuit.

[0048] In some embodiments, m, i and j also satisfy the following relationship: mi=jm.

[0049] Exemplarily, except for the 1st first transistor Q1 and the Nth first transistor QN, the bodies of the remaining first transistors can be simultaneously connected to the first voltage dividing branch 141 and the second voltage dividing branch 142. Specifically, taking the mth first transistor Qm as an example, mi is used to indicate the number of first transistors between the mth first transistor Qm and the i-th first transistor Qi, and jm is used to indicate the number of first transistors between the mth first transistor Qm and the j-th first transistor Qj. By separating the first transistors by the same number, the uniformity of the voltage division can be improved.

[0050] It should be noted that the number of first transistors separated from the first transistor connected through the first voltage divider branch 141 and the number of first transistors separated from the first transistor connected through the second voltage divider branch 142 may be the same or different, and this application does not impose any limitation.

[0051] In some embodiments, the first voltage-dividing branch 141 and the second voltage-dividing branch 142 each include at least one second transistor Q2 and at least one capacitor C; wherein the second transistor Q2 is connected between the first end and the second end of the corresponding voltage-dividing branch, and the capacitor is connected between the gate of the second transistor Q2 and the first end or the second end of the corresponding voltage-dividing branch.

[0052] Exemplarily, at least one second transistor Q2 and at least one capacitor are provided in the first voltage-dividing branch 141 and the second voltage-dividing branch 142, wherein the capacitor is connected between the controlled end of the second transistor Q2 and the first end or the second end of the voltage-dividing branch where the second transistor Q2 is located, so as to intermittently provide a bias signal for the second transistor Q2, so that the second transistor Q2 can be intermittently turned on. The second transistor Q2 is connected between the first end and the second end of the corresponding voltage-dividing branch, so that when the second transistor Q2 is turned on, the current leaked from the body of the first transistor can flow to the source or drain of another first transistor through the turned-on second transistor Q2, thereby making the voltage distribution of each first transistor more uniform.

[0053] In some embodiments, the number of second transistors Q2 in the first voltage-dividing branch 141 is equal to the number of second transistors Q2 in the second voltage-dividing branch 142, and the number of capacitors in the first voltage-dividing branch 141 is equal to the number of capacitors in the second voltage-dividing branch 142, so as to improve the convenience of circuit design and manufacturing and reduce the circuit manufacturing cost.

[0054] It should be noted that the electronic components in the first voltage-dividing branch 141 and the second voltage-dividing branch 142 may be the same or different, that is, the setting method and structure of the first voltage-dividing branch 141 and the second voltage-dividing branch 142 may be exactly the same, or the first voltage-dividing branch 141 or the second voltage-dividing branch 142 may be adjusted according to actual needs so that the voltage-dividing effect of the first voltage-dividing branch 141 is different from the voltage-dividing effect of the second voltage-dividing branch 142. The present application does not limit whether the first voltage-dividing branch 141 and the second voltage-dividing branch 142 are exactly the same.

[0055] See also Figure 3a , Figure 3a A schematic diagram of the structure of a voltage dividing branch provided in one embodiment of the present application.

[0056] In some embodiments, the switch unit 1411 of the first voltage-dividing branch 141 is a first switch unit 14111; the first switch unit 14111 includes at least one resistor and at least one second transistor Q2, the resistor and the second transistor Q2 are connected in series between the body of the mth first transistor Qm and the source of the i-th first transistor Qi, and the controlled end of the second transistor Q2 is connected to the switch bias unit 1412 of the first voltage-dividing branch 141.

[0057] Exemplarily, when the switch unit 1411 of the first voltage-dividing branch 141 is set to the first switch unit 14111, the first switch unit 14111 includes at least one resistor and at least one second transistor Q2, the resistor and the second transistor Q2 are connected in series between the body of the mth first transistor Qm and the source of the i-th first transistor Qi, and the controlled end of the second transistor Q2 is connected to the switch bias unit 1412 of the first voltage-dividing branch 141, so that when the switch bias unit 1412 provides a bias signal, the second transistor Q2 is turned on, thereby realizing voltage division of each first transistor.

[0058] In some embodiments, the first switch unit 14111 includes a second transistor Q2, and the resistor R and the second transistor Q2 are connected in series between the body of the mth first transistor Qm and the source of the ith first transistor Qi to achieve voltage division of the first transistors.

[0059] See also Figure 3b , Figure 3b A schematic structural diagram of a voltage divider branch provided in another embodiment of the present application.

[0060] In another embodiment, the first switching unit 14111 includes a plurality of second transistors Q2, and the plurality of second transistors Q2 are connected in series with a resistor between the body of the mth first transistor Qm and the source of the i-th first transistor Qi, and the controlled ends of the second transistors Q2 are connected to each other so that when the switching bias unit 1412 of the first voltage dividing branch 141 provides a bias signal, all the second transistors Q2 can be turned on, thereby realizing voltage division.

[0061] In one embodiment, if Figure 3b As shown, at least one resistor in the first switch unit 14111 includes a first resistor R1, a first end of the first resistor R1 is connected to the source of the i-th first transistor Qi, and a second end of the first resistor R1 is connected to the body of the m-th first transistor Qm through the second transistor Q2.

[0062] See also Figure 3c , Figure 3c A schematic structural diagram of a voltage dividing branch provided in yet another embodiment of the present application.

[0063] In another embodiment, at least one resistor in the first switch unit 14111 includes a second resistor R2, a first end of the second resistor R2 is connected to the source of the i-th first transistor Qi through the second transistor Q2, and a second end of the second resistor R2 is connected to the body of the m-th first transistor Qm.

[0064] See also Figure 3d , Figure 3d A schematic structural diagram of a voltage dividing branch provided in yet another embodiment of the present application.

[0065] In another embodiment, at least one resistor in the first switch unit 14111 includes a first resistor R1 and a second resistor R2, the first end of the first resistor R1 is connected to the source of the i-th first transistor Qi, the second end of the first resistor R1 is connected to the first end of the second resistor R2 through the second transistor Q2, and the second end of the second resistor R2 is connected to the body of the m-th first transistor Qm.

[0066] It should be noted that the resistor R in the first switch unit 14111 can be set in any of the three settings described above, but is not limited to any one of the three settings described above, and in the above settings, the first resistor R1 and / or the second resistor R2 can include multiple. For example, at least one resistor includes multiple first resistors R1, and the multiple first resistors R1 and at least one second transistor Q2 are connected in series between the source of the i-th first transistor Qi and the body of the m-th first transistor Qm. The remaining settings can refer to the setting of the first resistor R1, which will not be repeated here. For another example, at least one resistor includes multiple second resistors R2, and at least one second transistor Q2 and multiple second resistors R2 are connected in series between the source of the i-th first transistor Qi and the body of the m-th first transistor Qm. The remaining settings can refer to the setting of the second resistor R2, which will not be repeated here. For another example, at least one resistor includes multiple first resistors R1 and multiple second resistors R2. The specific setting can refer to the setting of the first resistor R1 and the second resistor R2, which will not be repeated here.

[0067] The present application does not limit the number and specific positions of the resistors. Those skilled in the art can set the resistors and their number based on the voltage difference between the first connection terminal 11 and the second connection terminal 12, the number of first transistors, the voltage difference between the body of the mth first transistor Qm and the source of the i-th first transistor Qi, etc.

[0068] See also Figure 4a , Figure 4a A schematic diagram of the structure of a switch bias unit 1412 provided in an embodiment of the present application.

[0069] In some embodiments, the switch bias unit 1412 of the first voltage divider branch 141 is a first switch bias unit 14121, and the first switch bias unit 14121 includes at least one capacitor, which is connected between the source of the i-th first transistor Qi and the body of the m-th first transistor Qm, and one end of the capacitor is connected to the controlled end of the second transistor Q2.

[0070] Exemplarily, the capacitor is connected between the source of the i-th first transistor Qi and the body of the m-th first transistor Qm, and one end of the capacitor is also connected to the controlled end of the second transistor Q2, so that when the first transistor is turned off, the capacitor can intermittently provide a bias signal to the second transistor Q2, thereby making the second transistor Q2 intermittently turned on, thereby achieving voltage division for different first transistors.

[0071] Please continue reading Figure 4aIn one embodiment, the first switch bias unit 14121 includes a first capacitor C1, a first end of the first capacitor C1 is connected to the source of the i-th first transistor Qi, and a second end of the first capacitor C1 is connected to the controlled end of the second transistor Q2 and the body of the m-th first transistor Qm; wherein the capacitance of the first capacitor C1 changes with the voltage difference across the first capacitor C1, that is, changes according to the voltage difference between the body of the m-th first transistor Qm and the source of the i-th first transistor Qi, so that when the voltage difference changes to a certain extent, a bias signal is provided to the second transistor Q2, so that the second transistor Q2 is turned on.

[0072] See also Figure 4b , Figure 4b A schematic diagram of the structure of a switch bias unit 1412 provided in another embodiment of the present application.

[0073] In another embodiment, if Figure 4b As shown, the first switch bias unit 14121 further includes a second capacitor C2; the second capacitor C2 is connected in reverse parallel to the first capacitor C1, and the capacitance of the second capacitor C2 changes with the voltage difference across the second capacitor C2.

[0074] In the specific implementation process, since the first capacitor C1 has directionality and the RF signal is an alternating signal, the first capacitor C1 cannot provide a bias signal to the second transistor Q2 in a negative voltage state, resulting in a short time for the second transistor Q2 to be turned on in one cycle of the RF signal. By setting a second capacitor C2 connected in reverse parallel to the first capacitor C1, the first switch bias unit 14121 can provide a bias signal to the second transistor Q2 in different states, thereby improving the voltage division effect of the circuit.

[0075] It should be noted that, by setting a transistor with its source and drain short-circuited as one plate of the first capacitor C1, and by using the gate of the transistor as the other plate of the first capacitor C1, the transistor can constitute a variable capacitance diode, that is, a first capacitor C1 with variable capacitance and directionality. Taking the transistor as an N-type field effect transistor as an example, when the voltage of the gate of the transistor is negative and the source and drain voltage is positive, the capacitance of the first capacitor C1 will change with the voltage difference between the gate and the source and drain. Correspondingly, another transistor with its source and drain short-circuited can also be set as the second capacitor C2, and its principle is similar to that of the first capacitor C1, which will not be repeated here.

[0076] See also Figure 4c , Figure 4c A schematic diagram of the structure of a switch bias unit 1412 provided in yet another embodiment of the present application.

[0077] In some embodiments, the first switch bias unit 14121 includes a first capacitor C1, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4; the first capacitor C1 and the third capacitor C3 are connected in series between the source of the i-th first transistor Qi and the body of the m-th first transistor Qm, and the connection node between the first capacitor C1 and the third capacitor C3 is connected to the controlled end of the second transistor Q2; the second capacitor C2 is connected in reverse parallel to the first capacitor C1, and the third capacitor C3 is connected in reverse parallel to the fourth capacitor C4.

[0078] It should be understood that the first switch bias unit 14121 can also be provided with a first capacitor C1, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4 at the same time to provide a bias signal for the second transistor Q2, so that the second transistor Q2 is intermittently turned on, thereby realizing voltage division of each first transistor in the switch branch 13. By providing the third capacitor C3 and the fourth capacitor C4, the first switch bias unit 14121 can provide a bias signal to the second transistor Q2 in a positive voltage or negative voltage state, so that the second transistor Q2 is turned on to divide the voltage, thereby improving the voltage division effect of the circuit and further improving the uniformity of the voltage division of multiple first transistors.

[0079] It should be noted that the capacitor setting method in the first switch bias unit 14121 can be but is not limited to any of the three settings mentioned above, and in the above settings, at least one of the first capacitor C1, the second capacitor C2, the third capacitor C3 and the fourth capacitor C4 can include multiple. For example, at least one capacitor includes multiple first capacitors C1, and the multiple first capacitors C1 are connected between the source of the i-th first transistor Qi and the body of the m-th first transistor Qm. The remaining settings can refer to the setting method of the first capacitor C1, which will not be repeated here. For another example, at least one resistor includes multiple second capacitors C2, and the multiple second capacitors C2 are connected between the source of the i-th first transistor Qi and the body of the m-th first transistor Qm. The remaining settings can refer to the setting method of the second capacitor C2, which will not be repeated here. For another example, at least one resistor also includes multiple third capacitors C3 and / or multiple fourth capacitors C4. The specific setting method can refer to the setting method of the third capacitor C3 and the fourth capacitor C4 mentioned above, which will not be repeated here.

[0080] In addition, the above Figure 4a-4c Any of the embodiments described can be applied to the Figure 3a-3d In the switch bias unit 1412 in any of the described embodiments, those skilled in the art may select a corresponding embodiment according to the voltage difference between the first connection terminal 11 and the second connection terminal 12, the number of first transistors, the voltage difference between the body of the mth first transistor Qm and the source of the i-th first transistor Qi, etc., and the present application does not limit this.

[0081] See also Figure 5 , Figure 5 A schematic structural diagram of a voltage divider branch provided in another embodiment of the present application.

[0082] In some embodiments, the switch unit 1411 of the first voltage-dividing branch 141 is a second switch unit 14112, and the second switch unit 14112 includes at least one third transistor Q3 and at least one third resistor R3, and the third transistor Q3 is connected between the body electrode of the mth first transistor Qm and the source electrode of the i-th first transistor Qi, and the controlled end of the third transistor Q3 is connected to the switch bias unit 1412 of the first voltage-dividing branch 141 through the third resistor R3.

[0083] Exemplarily, when the switch unit 1411 of the first voltage-dividing branch 141 is set to the second switch unit 14112, the second switch unit 14112 includes at least one third transistor Q3 and at least one third resistor R3, and the third transistor Q3 is connected between the body electrode of the mth first transistor Qm and the source electrode of the i-th first transistor Qi, so that when it is turned on, it can realize voltage division for the mth first transistor Qm and the i-th first transistor Qi, and the controlled end of the third transistor Q3 is connected to the switch bias unit 1412 of the first voltage-dividing branch 141 through the third resistor R3, so that the switch bias unit 1412 can provide a bias signal to the third transistor Q3 to control the third transistor Q3 to be turned on.

[0084] In a specific implementation process, the switch bias unit 1412 connected to the third resistor R3 may be, for example, the first switch bias unit 14121 provided above, or may be a switch bias unit 1412 having a structure different from that of the first switch bias unit 14121 .

[0085] See also Figure 6a , Figure 6a A schematic diagram of the structure of a switch bias unit 1412 provided in an embodiment of the present application.

[0086] In some embodiments, the switch bias unit 1412 of the first voltage dividing branch 141 is a second switch bias unit 14122, and the second switch bias unit 14122 includes at least one resistor and at least one capacitor C, and the resistor and capacitor C are connected in series between the body of the mth first transistor Qm and the source of the i-th first transistor Qi, and the resistor or capacitor C is also connected to the third resistor R3.

[0087] Exemplarily, the switch bias unit 1412 connected to the third circuit is a second switch bias unit 14122, and the second switch bias unit 14122 includes at least one resistor and at least one capacitor connected in series between the body of the mth first transistor Qm and the source of the i-th first transistor Qi, and the resistor or capacitor C is connected to the third resistor R3 to achieve the connection between the second switch bias unit 14122 and the second switch unit 14112, so that when the second switch bias unit 14122 provides a bias signal, the second switch unit 14112 is turned on, thereby achieving voltage division of the first transistor.

[0088] It should be noted that the second switch bias unit 14122 may also be connected to the first switch unit 14111 to provide a bias signal to the first switch unit 14111 so as to turn on the first switch unit 14111 .

[0089] It should be understood that the role played by the capacitor in the second switch bias unit 14122 is the same as that played by the capacitor in the first switch bias unit 14121, and will not be repeated here.

[0090] Exemplarily, the resistor R in the second switch bias unit 14122 may be set as in one of the following implementations.

[0091] Please continue reading Figure 6a In some embodiments, at least one resistor in the second switch bias unit 14122 includes a fourth resistor R4, a first end of the fourth resistor R4 is connected to the source of the i-th first transistor Qi, and a second end of the fourth resistor R4 is connected to the third resistor R3 and the body of the m-th first transistor Qm through a capacitor.

[0092] See also Figure 6b , Figure 6b A schematic diagram of the structure of a switch bias unit 1412 provided in another embodiment of the present application.

[0093] In another embodiment, at least one resistor in the second switch bias unit 14122 includes a fifth resistor R5, a first end of the fifth resistor R5 is connected to the source of the i-th first transistor Qi through the capacitor C, and a second end of the fifth resistor R5 is connected to the third resistor R3 and the body of the m-th first transistor Qm.

[0094] See also Figure 6c , Figure 6c A schematic diagram of the structure of a switch bias unit 1412 provided in yet another embodiment of the present application.

[0095] In another embodiment, at least one resistor in the second switch bias unit 14122 includes a fourth resistor R4 and a fifth resistor R5, the first end of the fourth resistor R4 is connected to the source of the i-th first transistor Qi, the second end of the fourth resistor R4 is connected to the first end of the fifth resistor R5 through a capacitor, the second end of the fifth resistor R5 is connected to the body of the m-th first transistor Qm, and the second end of the fifth resistor R5 is also connected to the third resistor R3.

[0096] It should be noted that the number of the fourth resistor R4 and / or the fifth resistor R5 in the above embodiments may be one or more, and the present application does not limit the specific number of the fourth resistor R4 and the fifth resistor R5.

[0097] See also Figure 6d , Figure 6d A schematic diagram of the structure of a switch bias unit 1412 provided in yet another embodiment of the present application.

[0098] In some embodiments, the capacitor in the second switch bias unit 14122 includes a fifth capacitor C5 and a sixth capacitor C6 connected in reverse parallel.

[0099] It should be understood that the fifth capacitor C5 and the sixth capacitor C6 are similar to the first capacitor C1 and the second capacitor C2 mentioned above, and both have directionality. By setting the fifth capacitor C5 and the sixth capacitor C6 connected in reverse parallel, when the first transistor is turned off, regardless of whether the RF signal is in the positive voltage range or the negative voltage range, the switch bias unit can intermittently provide a bias signal to the first switch unit 14111 or the second switch unit 14112, so that the first switch unit 14111 or the second switch unit 14112 is intermittently turned on, and then the first transistor is voltage divided by the turned-on first switch unit 14111 or the second switch unit 14112, so that the voltage division of multiple stacked first transistors in the RF switch circuit is more uniform.

[0100] In one embodiment, the switch unit 1421 of the second voltage-dividing branch 142 is a third switch unit, which includes at least one resistor and at least one fourth transistor. The resistor and the fourth transistor are connected in series between the body of the mth first transistor Qm and the drain of the jth first transistor Qj, and the controlled end of the fourth transistor is connected to the switch bias unit 1422 of the second voltage-dividing branch 142.

[0101] Exemplarily, the switch unit 1421 of the second voltage-dividing branch 142 includes a fourth transistor, and a resistor and the fourth transistor are connected in series between the body of the mth first transistor Qm and the drain of the jth first transistor Qj; or the switch unit 1421 of the second voltage-dividing branch 142 includes a plurality of fourth transistors, and the plurality of fourth transistors and the resistor are connected in series between the body of the mth first transistor Qm and the drain of the jth first transistor Qj, and the controlled ends of the fourth transistors are connected to each other.

[0102] Exemplarily, at least one resistor in the switch unit 1421 of the second voltage-dividing branch 142 includes a sixth resistor, a first end of the sixth resistor is connected to the drain of the jth first transistor Qj, and a second end of the sixth resistor is connected to the body of the mth first transistor Qm through a fourth transistor; or at least one resistor includes a seventh resistor, a first end of the seventh resistor is connected to the drain of the jth first transistor Qj through a fourth transistor, and a second end of the seventh resistor is connected to the body of the mth first transistor Qm; or at least one resistor includes a sixth resistor and a seventh resistor, and the sixth resistor, the fourth transistor and the seventh resistor are sequentially connected in series between the drain of the jth first transistor Qj and the body of the mth first transistor Qm. Exemplarily, the first end of the sixth resistor is connected to the drain of the jth first transistor Qj, the second end of the sixth resistor is connected to the first end of the seventh resistor through a fourth transistor, and the second end of the seventh resistor is connected to the body of the mth first transistor Qm. It should be understood that the above-mentioned sixth resistor and the seventh resistor can also be set to one or more, which is not limited here.

[0103] In the case where the switch unit 1421 of the second voltage-dividing branch 142 is an implementation as described above, the switch bias unit 1422 of the second voltage-dividing branch 142 is a third switch bias unit, and the third switch bias unit includes at least one capacitor, which is connected between the drain of the jth first transistor Qj and the body of the mth first transistor Qm, and one end of the capacitor is connected to the controlled end of the fourth transistor.

[0104] Exemplarily, the switch bias unit 1422 of the second voltage-dividing branch 142 includes a seventh capacitor, a first end of the seventh capacitor is connected to the drain of the jth first transistor Qj, and a second end of the seventh capacitor is connected to the controlled end of the fourth transistor and the body of the mth first transistor Qm; wherein the capacitance of the seventh capacitor changes with the voltage difference across the seventh capacitor.

[0105] Exemplarily, the switch bias unit 1422 of the second voltage dividing branch 142 further includes an eighth capacitor, which is connected in reverse parallel to the seventh capacitor, and the capacitance of the eighth capacitor changes according to the voltage difference across the eighth capacitor.

[0106] Exemplarily, the switch bias unit 1422 of the second voltage-dividing branch 142 includes a seventh capacitor, an eighth capacitor, a ninth capacitor and a tenth capacitor; the seventh capacitor and the ninth capacitor are connected in series between the body of the mth first transistor Qm and the drain of the jth first transistor Qj, and the connection node between the seventh capacitor and the ninth capacitor is connected to the controlled end of the fourth transistor; the eighth capacitor and the seventh capacitor are connected in reverse parallel, and the ninth capacitor and the tenth capacitor are connected in reverse parallel.

[0107] In another embodiment, the switch unit 1421 of the second voltage-dividing branch 142 includes at least one fifth transistor and at least one eighth resistor, the fifth transistor is connected between the body of the mth first transistor Qm and the drain of the jth first transistor Qj, and the controlled end of the fifth transistor is connected to the switch bias unit of the second voltage-dividing branch 142 through the eighth resistor.

[0108] In the case where the switch unit 1421 of the second voltage-dividing branch 142 is the embodiment described above, the switch bias unit 1422 of the second voltage-dividing branch 142 is a fourth switch bias unit, and the structure of the fourth switch bias unit can be the same as that of the second switch bias unit, except that the fourth switch bias unit is connected between the body of the mth first transistor Qm and the drain of the jth first transistor Qj. That is, the switch bias unit 1422 of the second voltage-dividing branch 142 includes at least one resistor and at least one capacitor, the resistor and the capacitor are connected in series between the body of the mth first transistor Qm and the drain of the jth first transistor Qj, and the resistor or the capacitor is also connected to the eighth resistor.

[0109] Exemplarily, at least one resistor in the fourth switch bias unit includes a ninth resistor, a first end of the ninth resistor is connected to the drain of the jth first transistor Qj, and a second end of the ninth resistor is connected to the eighth resistor and the body of the mth first transistor Qm through a capacitor; or, at least one resistor in the fourth switch bias unit includes a tenth resistor, a first end of the tenth resistor is connected to the drain of the jth first transistor Qj through a capacitor, and a second end of the tenth resistor is connected to the eighth resistor and the body of the mth first transistor Qm; or, at least one resistor in the fourth switch bias unit includes a ninth resistor and a tenth resistor, a first end of the ninth resistor is connected to the drain of the jth first transistor Qj, a second end of the ninth resistor is connected to the first end of the tenth resistor through a capacitor, and a second end of the tenth resistor is connected to the eighth resistor and the body of the mth first transistor Qm.

[0110] Exemplarily, the capacitor in the switch bias unit 1422 of the second voltage dividing branch 142 includes an eleventh capacitor and a twelfth capacitor connected in anti-parallel.

[0111] It should be understood that the above Figure 6a-6d The corresponding embodiments can be applied to Figure 5In the corresponding voltage divider branch, those skilled in the art may select any of the above embodiments according to the voltage difference between the first connection terminal 11 and the second connection terminal 12, the number of first transistors, the voltage difference between the body of the mth first transistor Qm and the source of the i-th first transistor Qi, etc., and this application does not limit this.

[0112] It should be noted that the switch unit 1411 and the switch bias unit 1412 in the second voltage-dividing branch 142 in the above embodiments can be set with reference to the setting method of the switch unit 1411 and the switch bias unit 1412 in the first voltage-dividing branch 141. Exemplarily, the switch unit 1411 in the second voltage-dividing branch 142 can have the same circuit structure as the switch unit in the first voltage-dividing branch 141, and the connection relationship between the two switch units can be symmetrically arranged with the body pole of the mth first transistor Qm as the center. Exemplarily, the switch bias unit 1412 in the second voltage-dividing branch 142 can have the same circuit structure as the switch bias unit in the first voltage-dividing branch 141, and the connection relationship between the two switch bias units can be symmetrically arranged with the body pole of the mth first transistor Qm as the center.

[0113] In some embodiments, the nth to zth first transistors are not connected to the voltage divider branch, wherein n and z are both positive integers and satisfy the following relationship: 0.25N<n<z<0.75N.

[0114] It should be noted that due to the characteristics of the stacking structure formed by multiple first transistors connected in series in the switch branch 13, when the number of first transistors is large, the voltage division unevenness of the first transistors near the two ends of the switch branch 13 will be more obvious, while the voltage division unevenness between the first transistors located in the middle part of the switch branch 13 is relatively slight. Therefore, the first transistors in the middle part can be disconnected from the voltage division branch to save the hardware cost of the RF switching circuit.

[0115] Exemplarily, the nth to zth first transistors are not connected to the voltage divider branch, wherein the number of the first transistors located at the front stage of the nth first transistor Qn is not less than one quarter of the total number of the first transistors, and similarly, the number of the first transistors located at the rear stage of the zth first transistor is not less than one quarter of the total number of the first transistors, so as to ensure that the first transistors near the two ends of the switch branch 13 can achieve voltage division more evenly, and the first transistors in the middle part are not connected to the voltage divider branch, which can simplify the structure of the RF switch circuit and reduce the manufacturing cost.

[0116] In addition, the first transistor and the second transistor Q2 are both field effect transistors, and the size of the first transistor is larger than that of the second transistor Q2.

[0117] In some embodiments, the first connection terminal 11 of the RF switch circuit is used to connect to the antenna through a tuning component, and the second connection terminal 12 of the RF switch circuit is used to be grounded or connected to a RF front-end module.

[0118] In a specific implementation process, the first connection terminal 11 of the RF switching circuit is also used to connect the antenna through a tuning component, and the second connection terminal 12 of the RF switching circuit is also used to ground or connect the RF front-end module to realize the reception and transmission of RF signals, and can also realize antenna impedance tuning to improve antenna efficiency.

[0119] The RF switch circuit provided in the above embodiment connects the body of the mth first transistor Qm to the source of the ith first transistor Qi through the first voltage dividing branch 141, and connects the body of the mth first transistor Qm to the drain of the jth first transistor Qj through the second voltage dividing branch 142, and the first voltage dividing branch 141 and the second voltage dividing branch 142 both include a switch unit 1411 and a switch bias unit 1412, so that when the first transistor is turned off, the switch bias unit 1412 can be used to transmit a bias signal to the switch unit 1411, so that the switch unit 1411 intermittently The RF switch 141 is turned on, so that the current on the source of the ith first transistor Qi can flow to the drain of the jth first transistor Qj through the switch unit 1411 turned on in the first voltage-dividing branch 141, and the current leaked from the body of the mth first transistor Qm can flow to the drain of the jth first transistor Qj through the switch unit 1411 turned on in the second voltage-dividing branch 142, thereby realizing the voltage division of the first transistors in the RF switch circuit, reducing the voltage that some of the first transistors need to withstand, making the voltage distribution of the RF switch circuit more uniform, and thus improving the voltage resistance of the RF switch circuit.

[0120] See also Figure 7 , Figure 7 A schematic diagram of a radio frequency module provided in accordance with an embodiment of the present application.

[0121] The present application also provides a radio frequency module, wherein the radio frequency module includes a radio frequency switching circuit 10 as provided in any of the above embodiments; the radio frequency module can be applied to electronic devices, for example, electronic devices include smart phones, tablet computers, smart watches and other devices with communication functions, and the above electronic devices can communicate with the outside world through the radio frequency module.

[0122] See also Figure 8 , Figure 8 A schematic diagram of an antenna tuner provided in accordance with an embodiment of the present application.

[0123] The present application also provides an antenna tuner, wherein the antenna tuner includes a plurality of parallel tuning branches, each tuning branch includes a tuning component and a radio frequency switch circuit 10 as provided in any of the above embodiments, the radio frequency switch circuit 10 is connected in series with the tuning component, and the working state of the antenna tuner can be adjusted through the radio frequency switch circuit 10 to achieve the reception and transmission of radio frequency signals and eliminate unnecessary resonance to improve the performance of the antenna. Specifically, the antenna tuner can be applied to the above-mentioned electronic devices, such as when applied to a mobile terminal, the antenna can be tuned by the antenna tuner to achieve more optimized performance in a wider frequency range.

[0124] It should be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0125] It should also be understood that the term "and / or" used in the specification of this application and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, including these combinations. It should be noted that, in this article, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "including a..." does not exclude the presence of other identical elements in the process, method, article or system including the element.

[0126] The serial numbers of the embodiments of the present application are for description only and do not represent the advantages and disadvantages of the embodiments. The above description is only a specific implementation mode of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A radio frequency switching circuit, characterized in that: include: a first connection end and a second connection end; A voltage-dividing branch, wherein the voltage-dividing branch comprises a first voltage-dividing branch and a second voltage-dividing branch, wherein the first voltage-dividing branch and the second voltage-dividing branch both comprise a switch unit and a switch bias unit; A switch branch, wherein the switch branch comprises N first transistors connected in series between the first connection terminal and the second connection terminal, the body of the mth first transistor is connected to the source of the ith first transistor through the switch unit in the first voltage dividing branch, and the body of the mth first transistor is connected to the drain of the jth first transistor through the switch unit in the second voltage dividing branch, wherein N, m, i and j are all positive integers and satisfy the following relationship: 1<m<N, 0<i<m, m<j≤N, N≥3; Wherein, when the first transistor is turned off, the switch bias unit is used to intermittently provide a bias signal to the switch unit so that the switch unit is intermittently turned on.

2. The radio frequency switch circuit according to claim 1, characterized in that: The body of the first first transistor is connected to the drain of the xth first transistor through the second voltage divider branch; the body of the Nth first transistor is connected to the source of the yth first transistor through the first voltage divider branch, where x and y are both positive integers and satisfy the following relationship: 1<x≤5, N-4≤y<N.

3. The radio frequency switch circuit according to claim 2, characterized in that: N, m, i, j, x and y also satisfy the following relationship: x-1=jm, Ny=mi.

4. The radio frequency switch circuit according to claim 1, characterized in that: m, i and j also satisfy the following relationship: mi≤4, jm≤4.

5. The radio frequency switch circuit according to claim 1, characterized in that: m, i and j also satisfy the following relationship: mi=jm.

6. The radio frequency switch circuit according to any one of claims 1 to 5, characterized in that: The first voltage dividing branch and the second voltage dividing branch each include at least one second transistor and at least one capacitor; The second transistor is connected between the first end and the second end of the corresponding voltage-dividing branch, and the capacitor is connected between the gate of the second transistor and the first end or the second end of the corresponding voltage-dividing branch.

7. According to the RF switching circuit of claim 6, the number of the second transistors in the first voltage-dividing branch is equal to the number of the second transistors in the second voltage-dividing branch, and the number of the capacitors in the first voltage-dividing branch is equal to the number of the capacitors in the second voltage-dividing branch.

8. The radio frequency switch circuit according to any one of claims 1 to 5, characterized in that: The switch unit of the first voltage-dividing branch is a first switch unit; the first switch unit includes at least one resistor and at least one second transistor, the resistor and the second transistor are connected in series between the body of the mth first transistor and the source of the ith first transistor, and the controlled end of the second transistor is connected to the switch bias unit of the first voltage-dividing branch; and / or The switch unit of the second voltage-dividing branch is a third switch unit, and the third switch unit includes at least one resistor and at least one fourth transistor. The resistor and the fourth transistor are connected in series between the body of the mth first transistor and the drain of the jth first transistor, and the controlled end of the fourth transistor is connected to the switch bias unit of the second voltage-dividing branch.

9. The radio frequency switch circuit according to claim 8, characterized in that: The first switch unit includes one second transistor, the resistor and the second transistor are connected in series between the body of the mth first transistor and the source of the ith first transistor; or, the first switch unit includes a plurality of second transistors, the plurality of second transistors and the resistor are connected in series between the body of the mth first transistor and the source of the ith first transistor, and the controlled ends of the second transistors are connected to each other; and / or, The third switching unit includes a fourth transistor, and the resistor and the fourth transistor are connected in series between the body of the mth first transistor and the drain of the jth first transistor; or, the switching unit of the second voltage divider branch includes multiple fourth transistors, and the multiple fourth transistors and the resistor are connected in series between the body of the mth first transistor and the drain of the jth first transistor, and the controlled ends of each of the fourth transistors are connected to each other.

10. The radio frequency switch circuit according to claim 9, characterized in that: At least one resistor in the first switch unit includes a first resistor, a first end of the first resistor is connected to the source of the i-th first transistor, and a second end of the first resistor is connected to the body of the m-th first transistor through the second transistor; Alternatively, at least one resistor in the first switch unit includes a second resistor, a first end of the second resistor is connected to the source of the i-th first transistor through the second transistor, and a second end of the second resistor is connected to the body of the m-th first transistor; Alternatively, at least one resistor in the first switch unit includes a first resistor and a second resistor, a first end of the first resistor is connected to a source of the i-th first transistor, a second end of the first resistor is connected to a first end of the second resistor through the second transistor, and a second end of the second resistor is connected to a body of the m-th first transistor; and / or, At least one resistor in the third switch unit includes a sixth resistor, a first end of the sixth resistor is connected to the drain of the jth first transistor, and a second end of the sixth resistor is connected to the body of the mth first transistor through the fourth transistor; Alternatively, at least one resistor in the third switch unit includes a seventh resistor, a first end of the seventh resistor is connected to the drain of the jth first transistor through the fourth transistor, and a second end of the seventh resistor is connected to the body of the mth first transistor; Alternatively, at least one resistor in the third switching unit includes a sixth resistor and a seventh resistor, a first end of the sixth resistor is connected to the drain of the jth first transistor, a second end of the sixth resistor is connected to the first end of the seventh resistor through the fourth transistor, and a second end of the seventh resistor is connected to the body of the mth first transistor.

11. The radio frequency switch circuit according to claim 8, characterized in that: The switch bias unit of the first voltage dividing branch is a first switch bias unit, the first switch bias unit includes at least one capacitor, the capacitor is connected between the source of the i-th first transistor and the body of the m-th first transistor, and one end of the capacitor is connected to the controlled end of the second transistor; and / or The switch bias unit of the second voltage dividing branch is a third switch bias unit, and the third switch bias unit includes at least one capacitor, which is connected between the drain of the jth first transistor and the body of the mth first transistor, and one end of the capacitor is connected to the controlled end of the fourth transistor.

12. The radio frequency switch circuit according to claim 11, characterized in that: The first switch bias unit comprises a first capacitor, a first end of the first capacitor is connected to the source of the i-th first transistor, and a second end of the first capacitor is connected to the controlled end of the second transistor and the body of the m-th first transistor; wherein the capacitance of the first capacitor changes with the voltage difference between the two ends of the first capacitor; and or, The third switch bias unit includes a seventh capacitor, a first end of the seventh capacitor is connected to the drain of the jth first transistor, and a second end of the seventh capacitor is connected to the controlled end of the fourth transistor and the body of the mth first transistor; wherein the capacitance of the seventh capacitor changes with the voltage difference across the seventh capacitor.

13. The radio frequency switch circuit according to claim 12, characterized in that: The first switch bias unit further includes a second capacitor; the second capacitor is connected in reverse parallel to the first capacitor, and the capacitance of the second capacitor changes with the voltage difference across the second capacitor; and / or, The third switch bias unit further includes an eighth capacitor, which is connected in reverse parallel to the seventh capacitor, and the capacitance of the eighth capacitor changes with the voltage difference across the eighth capacitor.

14. The radio frequency switch circuit according to claim 11, characterized in that: The first switch bias unit includes a first capacitor, a second capacitor, a third capacitor and a fourth capacitor; the first capacitor and the third capacitor are connected in series between the source of the i-th first transistor and the body of the m-th first transistor, and a connection node between the first capacitor and the third capacitor is connected to the controlled end of the second transistor; the second capacitor is connected in reverse parallel to the first capacitor, and the third capacitor is connected in reverse parallel to the fourth capacitor; and / or, The third switch bias unit includes a seventh capacitor, an eighth capacitor, a ninth capacitor and a tenth capacitor; the seventh capacitor and the ninth capacitor are connected in series between the body of the mth first transistor and the drain of the jth first transistor, and a connection node between the seventh capacitor and the ninth capacitor is connected to the controlled end of the fourth transistor; The eighth capacitor is connected in reverse parallel to the seventh capacitor, and the ninth capacitor is connected in reverse parallel to the tenth capacitor.

15. The radio frequency switch circuit according to claim 1, characterized in that: The switch unit of the first voltage-dividing branch is a second switch unit, the second switch unit includes at least one third transistor and at least one third resistor, the third transistor is connected between the body of the mth first transistor and the source of the ith first transistor, and the controlled end of the third transistor is connected to the switch bias unit of the first voltage-dividing branch through the third resistor; and / or The switch unit of the second voltage-dividing branch is a fourth switch unit, and the fourth switch unit includes at least one fifth transistor and at least one eighth resistor. The fifth transistor is connected between the body of the mth first transistor and the drain of the jth first transistor, and the controlled end of the fifth transistor is connected to the switch bias unit of the second voltage-dividing branch through the eighth resistor.

16. The radio frequency switch circuit according to claim 15, characterized in that: The switch bias unit of the first voltage dividing branch is a second switch bias unit, and the second switch bias unit includes at least one resistor and at least one capacitor, the resistor and the capacitor are connected in series between the body of the mth first transistor and the source of the ith first transistor, and the resistor or the capacitor is also connected to the third resistor; and / or The switch bias unit of the second voltage dividing branch is a fourth switch bias unit, and the fourth switch bias unit includes at least one resistor and at least one capacitor. The resistor and the capacitor are connected in series between the body of the mth first transistor Qm and the drain of the jth first transistor Qj, and the resistor or the capacitor is also connected to the eighth resistor.

17. The radio frequency switch circuit according to claim 16, characterized in that: The at least one resistor in the second switch bias unit includes a fourth resistor, a first end of the fourth resistor is connected to the source of the i-th first transistor, and a second end of the fourth resistor is connected to the third resistor and the body of the m-th first transistor through the capacitor; Alternatively, the at least one resistor in the second switch bias unit includes a fifth resistor, a first end of the fifth resistor is connected to the source of the i-th first transistor through the capacitor, and a second end of the fifth resistor is connected to the third resistor and the body of the m-th first transistor; Alternatively, at least one resistor in the second switch bias unit includes a fourth resistor and a fifth resistor, a first end of the fourth resistor is connected to the source of the i-th first transistor, a second end of the fourth resistor is connected to the first end of the fifth resistor through the capacitor, a second end of the fifth resistor is connected to the body of the m-th first transistor, and a second end of the fifth resistor is also connected to the third resistor; and / or The at least one resistor in the fourth switch bias unit includes a ninth resistor, a first end of the ninth resistor is connected to the drain of the jth first transistor, and a second end of the ninth resistor is connected to the eighth resistor and the body of the mth first transistor through the capacitor; Alternatively, the at least one resistor in the fourth switch bias unit includes a tenth resistor, a first end of the tenth resistor is connected to the drain of the jth first transistor through the capacitor, and a second end of the tenth resistor is connected to the eighth resistor and the body of the mth first transistor; Alternatively, at least one resistor in the fourth switch bias unit includes a ninth resistor and a tenth resistor, a first end of the ninth resistor is connected to the drain of the jth first transistor, a second end of the ninth resistor is connected to the first end of the tenth resistor through a capacitor, and a second end of the tenth resistor is connected to the eighth resistor and the body of the mth first transistor.

18. The radio frequency switch circuit according to claim 16 or 17, characterized in that: The capacitor in the second switch bias unit includes a fifth capacitor and a sixth capacitor connected in reverse parallel; and / or the capacitor in the fourth switch bias unit includes an eleventh capacitor and a twelfth capacitor connected in reverse parallel.

19. The radio frequency switch circuit according to any one of claims 1 to 5, characterized in that: The nth to zth first transistors are not connected to the voltage dividing branch, wherein n and z are both positive integers and satisfy the following relationship: 0.25N<n<z<0.75N.

20. The radio frequency switch circuit according to any one of claims 1 to 5, characterized in that: When the radio frequency signal is transmitted between the first connection end and the second connection end of the switch branch, it passes through the i-th first transistor, the m-th first transistor and the j-th first transistor in sequence.

21. The RF switch circuit according to any one of claims 1 to 5, wherein the first connection end of the RF switch circuit is used to connect to an antenna through a tuning component, and the second connection end of the RF switch circuit is used to be grounded or connected to a RF front-end module.

22. A radio frequency module, characterized in that: The radio frequency module includes the radio frequency switching circuit as described in any one of claims 1-21.

23. An antenna tuner, characterized in that: It comprises a plurality of parallel tuning branches, each tuning branch comprises a tuning component and a radio frequency switching circuit as claimed in any one of claims 1 to 21, and the radio frequency switching circuit is connected in series with the tuning component.

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