CN219372406U - Radio frequency attenuation circuit and radio frequency module - Google Patents

Abstract

The application discloses a radio frequency attenuation circuit and a radio frequency module. The radio frequency attenuation circuit comprises an attenuation module, a bypass switch and a control module. The attenuation module comprises a first signal end, a second signal end, a first attenuation unit and a second attenuation unit. The first end of the first attenuation unit is connected with the first signal end, and the second end of the first attenuation unit is connected with the second signal end; one end of the first attenuation branch is connected to the first end of the first attenuation unit, and the other end of the first attenuation branch is connected to the second end of the first attenuation unit. The second attenuation unit comprises N second attenuation branches, one end of each second attenuation branch is connected to the second end of the first attenuation unit, and the other end of each second attenuation branch is grounded. The bypass switch is connected to the first signal terminal and the second signal terminal of the attenuation module. The control module is connected to the bypass switch. When the radio frequency attenuation circuit works in the bypass mode, the attenuation degree of the radio frequency signal is smaller than that of the radio frequency attenuation circuit in the prior art.

Description

Radio frequency attenuation circuit and radio frequency module

Technical Field

The present application relates to the field of radio frequency technologies, and in particular, to a radio frequency attenuation circuit and a radio frequency module.

Background

In the field of radio frequency technology, a radio frequency attenuation circuit is generally disposed in a radio frequency front end module of a mobile terminal, and the radio frequency attenuation circuit is used for accurately adjusting radio frequency power of a radio frequency signal. The radio frequency attenuation circuit generally comprises two operation modes: bypass mode and access mode. Specifically, the bypass mode refers to a mode in which the radio frequency signal does not pass through an attenuation module in the radio frequency attenuation circuit, so that the radio frequency signal cannot be attenuated. In contrast, the access mode refers to a mode in which the radio frequency signal passes through the attenuation module and is subjected to signal attenuation by the attenuation module.

In the existing radio frequency attenuation circuit, a structure that a plurality of attenuation modules are connected in series and then connected in parallel with a bypass switch is generally adopted, wherein the attenuation modules are used for providing different attenuation amounts and are provided with corresponding control switches. When the radio frequency attenuation circuit is in a bypass mode, the bypass switch is closed and the plurality of control switches are opened; when the radio frequency attenuation circuit is in an access mode, the bypass switch is opened, and at least one control switch is closed, so that the attenuation module corresponding to the control switch in the closed state carries out signal attenuation on radio frequency signals.

Then, when the radio frequency attenuation circuit is in the bypass mode, in the case that the bypass switch is in the closed state and the plurality of control switches are in the open state, parasitic capacitance to ground exists when the plurality of control switches are opened, and therefore a plurality of signal leakage paths exist in the radio frequency attenuation circuit. Thus, even in the bypass mode, there is still a large attenuation of the rf signal as it passes through the rf attenuation circuit.

Disclosure of Invention

The embodiment of the application provides a radio frequency attenuation circuit and a radio frequency module.

According to a first aspect of the present application, an embodiment of the present application provides a radio frequency attenuation circuit, which includes an attenuation module, a bypass switch, and a control module. The attenuation module comprises a first signal end, a second signal end, a first attenuation unit and a second attenuation unit. The first attenuation unit comprises a first end, a second end and N first attenuation branches. The first end of the first attenuation unit is connected with the first signal end, and the second end of the first attenuation unit is connected with the second signal end; one end of the first attenuation branch is connected with the first end of the first attenuation unit, the other end of the first attenuation branch is connected with the second end of the first attenuation unit, and N is larger than 1. The second attenuation unit comprises N second attenuation branches, one end of each second attenuation branch is connected to the second end of the first attenuation unit, and the other end of each second attenuation branch is grounded. The bypass switch is connected to the first signal terminal and the second signal terminal of the attenuation module. The control module is connected to the bypass switch.

In some alternative embodiments, the first attenuation branch includes a first attenuation resistor and a first attenuation switch, one end formed by connecting the first attenuation resistor and the first attenuation switch in series is connected to the first end of the first attenuation unit, and the other end is connected to the second end of the first attenuation unit; the N first attenuation branches comprise N first attenuation resistors with different resistance values; the control module is also connected with N first attenuation switches included in the N first attenuation branches.

In some alternative embodiments, the second attenuation branch includes a second attenuation resistor and a second attenuation switch, where one end formed by connecting the second attenuation resistor and the second attenuation switch in series is connected to the second end of the first attenuation unit, and the other end is grounded; the resistance values of N second attenuation resistors included in the N second attenuation branches are different; the control module is also connected with N second attenuation switches included in the N second attenuation branches.

Wherein in some alternative embodiments, the attenuation module further comprises a third attenuation unit; the third attenuation unit comprises N third attenuation branches, one end of each third attenuation branch is connected to the first end of the first attenuation unit, and the other end of each third attenuation branch is grounded.

In some optional embodiments, the third attenuation branch includes a third attenuation resistor and a third attenuation switch, where one end formed by connecting the third attenuation resistor and the third attenuation switch in series is connected to the first end of the first attenuation unit, and the other end is grounded; the resistance values of N third attenuation resistors included in the N third attenuation branches are different; the control module is also connected with N third attenuation switches included in the N third attenuation branches.

Wherein, in some alternative embodiments, the attenuation module further comprises a first control switch and a second control switch; the first control switch is connected between the first signal end and the first end of the first attenuation unit; the second control switch is connected between the second signal end and the second end of the first attenuation unit; the control module is also connected to the first control switch and the second control switch.

Wherein, in some alternative embodiments, the attenuation module further comprises a fourth attenuation unit; the fourth attenuation unit comprises a first end, a second end and N fourth attenuation branches, the first end of the fourth attenuation unit is connected with the second end of the first attenuation unit, and the second end of the fourth attenuation unit is connected with the second signal end; one end of the fourth attenuation branch is connected to the first end of the fourth attenuation unit, and the other end of the fourth attenuation branch is connected to the second end of the fourth attenuation unit.

In some alternative embodiments, the fourth attenuation branch includes a fourth attenuation resistor and a fourth attenuation switch, where one end formed by connecting the fourth attenuation resistor and the fourth attenuation switch in series is connected to the first end of the fourth attenuation unit, and the other end is connected to the second end of the fourth attenuation unit; the resistance values of N fourth attenuation resistors included in the N fourth attenuation branches are different; the control module is also connected with N fourth attenuation switches included in the N fourth attenuation branches.

Wherein in some alternative embodiments, the attenuation module further comprises a third control switch and a fourth control switch; the third control switch is connected between the first signal end and the first end of the first attenuation unit; the fourth control switch is connected between the second signal end and the second end of the fourth attenuation unit; the control module is also connected to the third control switch and the fourth control switch.

According to a second aspect of the present application, an embodiment of the present application provides a radio frequency module, including the radio frequency attenuation circuit described above.

In the radio frequency attenuation circuit and the radio frequency module provided with the radio frequency attenuation circuit provided by the embodiment of the application, the radio frequency attenuation circuit comprises an attenuation module, a bypass switch and a control module. The attenuation module comprises a first signal end, a second signal end, a first attenuation unit and a second attenuation unit. The first attenuation unit comprises N first attenuation branches, one end of each first attenuation branch is connected to the first end of the corresponding first attenuation unit, the other end of each first attenuation branch is connected to the second end of the corresponding first attenuation unit, and N is larger than 1. The second attenuation unit comprises N second attenuation branches, one end of each second attenuation branch is connected to the second end of the first attenuation unit, and the other end of each second attenuation branch is grounded. The bypass switch is connected to the first signal terminal and the second signal terminal of the attenuation module. The control module is connected to the bypass switch. The applicant finds through a lot of experiments that, since the first attenuation unit and the second attenuation unit in the radio frequency attenuation circuit provided in the present application each include a plurality of branches connected in parallel with each other, when the radio frequency attenuation circuit works in the bypass mode, the equivalent capacitance value of the parasitic capacitance of the plurality of parallel branches is smaller than that of the parasitic capacitance in the prior art, so that the attenuation degree of the radio frequency attenuation circuit on the radio frequency signal is smaller than that of the radio frequency attenuation circuit in the prior art, that is, the topology structure of the radio frequency attenuation circuit provided in the present application can have smaller signal leakage in the bypass mode.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a prior art rf attenuator circuit.

The equivalent circuit schematic of the rf attenuation circuit of fig. 1 in fig. 2 operating in bypass mode.

Fig. 3 is a schematic diagram of a first structure of a radio frequency attenuation circuit according to an embodiment of the present application.

Fig. 4 is a schematic diagram of a second structure of a radio frequency attenuation circuit according to an embodiment of the present application.

Fig. 5 is a schematic diagram of an equivalent circuit of the rf attenuation circuit of fig. 4 operating in bypass mode.

Fig. 6 is a schematic diagram of a third structure of a radio frequency attenuation circuit according to an embodiment of the present application.

Fig. 7 is a schematic diagram of signal attenuation according to an embodiment of the present application.

Fig. 8 is a schematic diagram of a fourth configuration of a radio frequency attenuation circuit according to an embodiment of the present application.

Fig. 9 is a schematic diagram of an equivalent circuit of the rf attenuation circuit of fig. 8 operating in bypass mode.

Fig. 10 is a schematic diagram of a fifth structure of a radio frequency attenuation circuit according to an embodiment of the present application.

Fig. 11 is a schematic diagram of another signal attenuation provided in an embodiment of the present application.

Fig. 12 is a schematic structural diagram of a radio frequency module according to an embodiment of the present application.

Detailed Description

In order to enable those skilled in the art to better understand the present application, the following description will make clear and complete descriptions of the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

In the existing radio frequency attenuation circuit, a structure that a plurality of attenuation modules are connected in series and then connected in parallel with a bypass switch is generally adopted, wherein the attenuation modules are used for providing different attenuation amounts and are provided with corresponding control switches. Referring to fig. 1, the radio frequency attenuation circuit in fig. 1 has three attenuation modules, and the three attenuation modules are connected in series and then connected in parallel with a bypass switch, where each attenuation module is used for providing different attenuation and includes three resistors and three control switches. The end A is a signal input end of the radio frequency attenuation circuit, and the end B is a signal output end of the radio frequency attenuation circuit. When the radio frequency attenuation circuit is in the bypass mode, the bypass switch is closed, and the control switches are opened, at this time, the radio frequency signal flowing in from the A end flows to the B end through the bypass switch. When the radio frequency attenuation circuit is in an access mode, the bypass switch is opened, and the control switch in the at least one attenuation module is closed, so that the attenuation module corresponding to the control switch in the closed state carries out signal attenuation on the radio frequency signal, namely, the radio frequency signal flowing in from the A end flows to the B end through the at least one attenuation module.

Then, when the radio frequency attenuation circuit is in the bypass mode, in the case that the bypass switch is in the closed state and the plurality of control switches are in the open state, parasitic capacitance to ground exists when the plurality of control switches are opened, and therefore a plurality of signal leakage paths exist in the radio frequency attenuation circuit. Referring to fig. 2, fig. 2 is an equivalent circuit schematic diagram of the rf attenuation circuit in the bypass mode. Since the bypass switch S10 is in the closed state, it can be equivalent to the resistor R10, and the control switches S1 to S9 are all in the open state, and thus can be equivalent to the capacitors C1 to C9. For simplicity of calculation, let c1=c2=c3=c4=c5=c6=c7=c8=c9=c, r1=r4=r7, r2=r3=r5=r6=r8=r9,and +.>When the influence of the equivalent resistance R10 of the bypass switch S10 on the circuit is ignored, the ratio of the B terminal voltage to the a terminal voltage is:

since Z1< z0+z1, the a-terminal voltage will be greater than the B-terminal voltage. That is, even in the bypass mode, the rf signal still has a larger attenuation when passing through the rf attenuation circuit, which results in a more serious signal leakage.

In order to solve the above problems, the applicant has made extensive studies to propose a new topology of a radio frequency attenuation circuit. Referring to fig. 3, an embodiment of a radio frequency attenuation circuit 100 is provided. The radio frequency attenuation circuit 100 includes an attenuation module 10, a bypass switch 30, and a control module 50. The attenuation module 10 includes a first signal terminal 110, a second signal terminal 120, a first attenuation unit 130, and a second attenuation unit 140. The first attenuation unit 130 includes a first end 134, a second end 136, and N first attenuation branches 132. The first end 134 of the first attenuation unit 130 is connected to the first signal end 110, and the second end 136 of the first attenuation unit 130 is connected to the second signal end 120; one end of the first attenuation branch 132 is connected to the first end 134 of the first attenuation unit 130, and the other end is connected to the second end 136 of the first attenuation unit 130, where n is greater than 1. The second attenuation unit 140 includes N second attenuation branches 142, where one end of the second attenuation branch 142 is connected to the second end 136 of the first attenuation unit 130, and the other end is grounded. The bypass switch 30 is connected to the first signal terminal 110 and the second signal terminal 120 of the attenuation module 10. The control module 50 is connected to the bypass switch 30.

Because the first attenuation unit 130 and the second attenuation unit 140 in the radio frequency attenuation circuit 100 provided in the present application each include a plurality of branches connected in parallel with each other, when the radio frequency attenuation circuit 100 works in the bypass mode, the equivalent capacitance value of the parasitic capacitance of the plurality of parallel branches is smaller than that of the parasitic capacitance in the prior art, so that the attenuation degree of the radio frequency attenuation circuit 100 to the radio frequency signal is smaller than that of the radio frequency attenuation circuit in the prior art, that is, the topology structure of the radio frequency attenuation circuit 100 provided in the present application can have smaller signal leakage in the bypass mode.

Each of the blocks in the rf attenuation circuit 100 is described in detail below.

The attenuation module 10 may include a first signal terminal 110 and a second signal terminal 120. The first signal terminal 110 may be a signal input terminal, and the second signal terminal 120 may be a signal output terminal. The first signal terminal 110 may also be a signal output terminal, and the second signal terminal 120 may be a signal input terminal. In the following embodiments, the first signal terminal 110 is taken as a signal input terminal for illustration.

The bypass switch 30 is connected to the first signal terminal 110 and the second signal terminal 120 of the attenuation module 10, and is used for controlling the operation mode of the radio frequency attenuation circuit 100. Specifically, when the bypass switch 30 is in the closed state, the radio frequency attenuation circuit 100 is in the bypass mode. Conversely, when the bypass switch 30 is in the off state, the radio frequency attenuation circuit 100 is in the on mode. As an embodiment, the bypass switch 30 may be a Metal-Oxide-semiconductor field effect transistor (MOSFET), hereinafter referred to as MOS transistor. The source and the drain of the MOS transistor may be connected to the first signal end 110 and the second signal end 120 of the attenuation module 10, respectively, and the gate of the MOS transistor may be connected to the control module 50, and the MOS transistor is in a closed or off state under the control of the control module 50. Specifically, the bypass switch 30 may be an N-channel MOS transistor or a P-channel MOS transistor, which is not particularly limited in this embodiment.

The control module 50 is connected to the bypass switch 30 for controlling the operation state of the bypass switch 30. The control module 50 may be a micro control unit (Micro Controller Unit, MCU) or may be implemented by using other control chips, which is not limited in this embodiment. Illustratively, taking the bypass switch 30 as an N-channel MOS transistor, the control module 50 is connected to the gate of the N-channel MOS transistor. When the control module 50 outputs high-level voltage to the grid electrode, the N-channel MOS transistor is in a closed state; conversely, when the control module 50 outputs a low level voltage to the gate, the N-channel MOS transistor is in an off state. Specifically, the high level voltage may be determined by an external supply, for example, the high level voltage may be 1.8V, 2.5V, or the like, and the low level voltage may be 0V, which is not particularly limited in this embodiment.

In this embodiment, the attenuation module 10 may further include a first attenuation unit 130 and a second attenuation unit 140, for providing signal attenuation for the radio frequency signal when the radio frequency attenuation circuit 100 is in the access mode.

The first attenuation unit 130 may include a first end 134, a second end 136, and N first attenuation branches 132. The first end 134 of the first attenuation unit 130 is connected to the first signal end 110, and the second end 136 of the first attenuation unit 130 is connected to the second signal end 120. One end of the first attenuation branch 132 is connected to the first end 134 of the first attenuation unit 130, and the other end is connected to the second end 136 of the first attenuation unit 130, where n is greater than 1.

In this embodiment, the first attenuation branch 132 may include a first attenuation resistor 1321 and a first attenuation switch 1323, where one end formed by connecting the first attenuation resistor 1321 and the first attenuation switch 1323 in series is connected to the first end 134 of the first attenuation unit 130, and the other end is connected to the second end 136 of the first attenuation unit 130. That is, the N first attenuation branches 132 are connected in parallel with each other. The N first attenuation resistors 1321 included in the N first attenuation branches 132 have different resistance values. Thus, different degrees of signal attenuation can be achieved as the radio frequency signal passes through the different first attenuation branches 132.

In some possible embodiments, the N first attenuation switches 1323 may be MOS transistors, and the control module 50 is further connected to the N first attenuation switches 1323 included in the N first attenuation branches 132, for example, the control module 50 may be connected to gates of the N MOS transistors, and used to control whether the first attenuation branch 132 where the MOS transistor is located is connected to the radio frequency attenuation circuit 100.

In some possible embodiments, N has a value of 3, that is, the first attenuation unit 130 includes three first attenuation branches 132. Referring to fig. 4, the three first attenuation branches 132 may be a branch formed by connecting the first attenuation switch S1 and the first attenuation resistor R1 in series, a branch formed by connecting the first attenuation switch S2 and the first attenuation resistor R2 in series, and a branch formed by connecting the first attenuation switch S3 and the first attenuation resistor R3 in series, respectively.

The second attenuation unit 140 includes N second attenuation branches 142, where one end of the second attenuation branch 142 is connected to the second end 136 of the first attenuation unit 130, and the other end is grounded. That is, the N second attenuation branches 142 are connected in parallel with each other. In this embodiment, the second attenuation branch 142 may include a second attenuation resistor 1421 and a second attenuation switch 1423, where one end formed by connecting the second attenuation resistor 1421 and the second attenuation switch 1423 in series is connected to the second end 136 of the first attenuation unit 130, and the other end is grounded. The N second attenuation branches comprise N second attenuation resistors with different resistance values. Thus, different degrees of signal attenuation can be achieved as the radio frequency signal passes through the different second attenuation branches 142.

In some possible embodiments, the N second attenuation switches 1423 may be MOS transistors, and the control module 50 is further connected to the N second attenuation switches 1423 included in the N second attenuation branches 142, for example, the control module 50 may be connected to gates of the N MOS transistors, and used to control whether the second attenuation branch 142 where the MOS transistor is located is connected to the radio frequency attenuation circuit 100.

In some possible embodiments, N has a value of 3, i.e. the second attenuation unit 140 comprises three second attenuation branches 142. Referring to fig. 4, the three second attenuation branches 142 may be a branch formed by connecting the second attenuation switch S7 and the second attenuation resistor R7 in series, a branch formed by connecting the second attenuation switch S8 and the second attenuation resistor R8 in series, and a branch formed by connecting the second attenuation switch S9 and the second attenuation resistor R9 in series, respectively.

In some embodiments, referring to fig. 4, the attenuation module 10 may further include a third attenuation unit 150. The third attenuation unit 150 includes N third attenuation branches 152, where one end of the third attenuation branch 152 is connected to the first end 134 of the first attenuation unit 130, and the other end is grounded. That is, the N third attenuation branches 152 are connected in parallel with each other. Specifically, in the embodiment shown in fig. 4, the third attenuation unit 150 and the second attenuation unit 140 are respectively located on opposite sides of the first attenuation unit 130, that is, the attenuation module 10 in fig. 4 is generally in a shape of a "n".

Specifically, the third attenuation branch 152 may include a third attenuation resistor 1521 and a third attenuation switch 1523, where one end formed by connecting the third attenuation resistor 1521 and the third attenuation switch 1523 in series is connected to the first end 134 of the first attenuation unit 130, and the other end is grounded. The N third attenuation branches 152 include N third attenuation resistors 1521 with different resistance values. Thus, different degrees of signal attenuation can be achieved as the radio frequency signal passes through the different third attenuation branches 152.

In some possible embodiments, the N third attenuation switches 1523 may be MOS transistors, and the control module 50 is further connected to the N third attenuation switches 1523 included in the N third attenuation branches 152, for example, the control module 50 may be connected to gates of the N MOS transistors, and used to control whether the third attenuation branch 152 where the MOS transistor is located is connected to the radio frequency attenuation circuit 100.

In some possible embodiments, N has a value of 3, i.e. the third attenuation unit 150 comprises three third attenuation branches 152. Referring to fig. 4, the three third attenuation branches 152 may be a branch formed by connecting the third attenuation switch S4 and the third attenuation resistor R4 in series, a branch formed by connecting the third attenuation switch S5 and the third attenuation resistor R5 in series, and a branch formed by connecting the third attenuation switch S6 and the third attenuation resistor R6 in series, respectively.

Specifically, in the embodiment shown in fig. 4, S1, R1, S6, R6, S9, and R9 may form a first "pi" type attenuator, S2, R2, S5, R5, S8, and R8 may form a second "pi" type attenuator, and S3, R3, S4, R4, S7, and R7 may form a third "pi" type attenuator. Wherein different attenuators may be provided for different attenuation ratios of the radio frequency signal. Here, taking the first "n" type attenuator composed of R1, R6, and R9 as an example, since the circuit configuration is symmetrical, when the input impedance, the output impedance, the load impedance, and the source output impedance of the attenuator are all equal (for example, 50 ohms), the resistance value of R6 and the resistance value of R9 are equal. The resistance values of R1, R6 and R9 may be determined by calculating or searching a corresponding resistance parameter table according to a formula under the condition that the attenuation ratio is known. Specifically, the larger the decay ratio, the smaller the resistance values of R6 and R9, and the larger the resistance value of R1.

It is to be noted that the attenuation module 10 in the rf attenuation circuit 100 shown in fig. 4 includes 9 resistors and 9 switches, and has the same hardware amount as the rf attenuation circuit in fig. 1. Similarly, the equivalent circuit analysis is performed for the radio frequency attenuation circuit 100 in fig. 4 in the bypass mode. Referring to fig. 5, fig. 5 shows the rf attenuation in the bypass modeAn equivalent circuit schematic of the circuit. Since the bypass switch 30 is in the closed state, it can be equivalent to the resistor R10, and the switches S1 to S9 are all in the open state, and thus can be equivalent to the capacitors C1 to C9. For simplicity of calculation, let c1=c2=c3=c4=c5=c6=c7=c8=c9=c, r1=r2=r3, r4=r5=r6=r7=r8=r9,and +.>When the influence of the equivalent resistance R10 of the bypass switch 30 on the circuit is ignored, the ratio of the B terminal voltage to the a terminal voltage is:

therefore, in the case where the voltages at the a terminals are the same, the ratio of the voltages at the B terminals and the a terminals corresponding to the radio frequency attenuating circuit 100 in fig. 4 is greater than the ratio of the voltages at the B terminals and the a terminals corresponding to the radio frequency attenuating circuit in fig. 1. That is, with the same amount of hardware, the topology employing the radio frequency attenuation circuit 100 of fig. 4 may have less signal leakage in bypass mode. Therefore, compared with the hardware circuit in the prior art, the radio frequency attenuation circuit provided in the application has smaller leakage to radio frequency signals in a bypass state.

In some possible embodiments, the attenuation module 10 may further include a first control switch 161 and a second control switch 163. Referring to fig. 6, the first control switch 161 is connected between the first signal terminal 110 and the first terminal 134 of the first attenuation unit 130. The second control switch 163 is connected between the second signal terminal 120 and the second terminal 136 of the first attenuation unit 130. Specifically, the first control switch 161 and the second control switch 163 may be MOS transistors, and the control module 50 is further connected to the first control switch 161 and the second control switch 163, for example, the control module 50 may be respectively connected to gates of the MOS transistors, for controlling the working states of the MOS transistors. In this embodiment, when the rf attenuation circuit 100 operates in the bypass mode, the first control switch 161 and the second control switch 163 are both in an off state; conversely, when the rf attenuation circuit 100 is operating in the access mode, both the first control switch 161 and the second control switch 163 are in a closed state.

Referring to fig. 7, fig. 7 is a schematic diagram illustrating signal attenuation of the rf attenuation circuits shown in fig. 1, fig. 4, and fig. 6 in a bypass mode, respectively. The first curve in fig. 7 is a signal attenuation trend of the radio frequency attenuation circuit in fig. 1 in the bypass mode, the second curve is a signal attenuation trend of the radio frequency attenuation circuit in fig. 4 in the bypass mode, and the third curve is a signal attenuation trend of the radio frequency attenuation circuit in fig. 6 in the bypass mode. As is apparent from fig. 7, the new topology of the rf attenuation circuit 100 in fig. 4 and 6 can have smaller signal leakage in the bypass mode, i.e., the rf attenuation circuit 100 has smaller insertion loss when inputting rf signals of different frequencies, compared to the prior art (i.e., fig. 1). In addition, when the frequency of the input radio frequency signal is higher than 3GHz, the signal insertion loss of the radio frequency attenuation circuit 100 in fig. 6 is smaller than that of the radio frequency attenuation circuit 100 in fig. 4. That is, in the case of adding the first control switch 161 and the second control switch 163, the radio frequency attenuation circuit 100 in the bypass mode can have less signal leakage to the radio frequency signal.

In other embodiments, referring to fig. 8, the attenuation module 10 may further include a fourth attenuation unit 170. The fourth attenuation unit 170 includes a first end 174, a second end 176, and N fourth attenuation branches 172, where the first end 174 of the fourth attenuation unit 170 is connected to the second end 136 of the first attenuation unit 130, and the second end 176 of the fourth attenuation unit 170 is connected to the second signal end 120. Specifically, one end of the fourth attenuation branch 172 is connected to the first end 174 of the fourth attenuation unit 170, and the other end of the fourth attenuation branch 172 is connected to the second end 176 of the fourth attenuation unit 170. That is, the N fourth attenuation branches 172 are connected in parallel with each other. Specifically, in the embodiment shown in fig. 8, the second attenuation unit 140 is located in the middle of the first attenuation unit 130 and the fourth attenuation unit 170, that is, the attenuation module 10 in fig. 8 is overall "T" shaped.

Specifically, the fourth attenuation branch 172 may include a fourth attenuation resistor 1721 and a fourth attenuation switch 1723, where one end formed by connecting the fourth attenuation resistor 1721 and the fourth attenuation switch 1723 in series is connected to the first end 174 of the fourth attenuation unit 170, and the other end is connected to the second end 176 of the fourth attenuation unit 170. The N fourth attenuation branches 172 include N fourth attenuation resistors 1721 having different resistance values. Thus, as the radio frequency signal passes through the different fourth attenuation branch 172, different degrees of signal attenuation can be achieved.

In some possible embodiments, the N fourth attenuation switches 1723 may be MOS transistors, and the control module 50 is further connected to the N fourth attenuation switches 1723 included in the N fourth attenuation branches 172, for example, the control module 50 may be connected to gates of the N MOS transistors, and used to control whether the fourth attenuation branch 172 where the MOS transistor is located is connected to the radio frequency attenuation circuit 100.

In some possible embodiments, N has a value of 3, i.e., the fourth attenuation unit 170 includes three fourth attenuation branches 172. In the embodiment shown in fig. 8, the three fourth attenuation branches 172 may be a branch formed by connecting the fourth attenuation switch S10 and the fourth attenuation resistor R10 in series, a branch formed by connecting the fourth attenuation switch S11 and the fourth attenuation resistor R11 in series, and a branch formed by connecting the fourth attenuation switch S12 and the fourth attenuation resistor R12 in series, respectively.

Specifically, in the embodiment shown in fig. 8, S1, R1, S7, R7, S10, and R10 may form a first "T" type attenuator, S2, R2, S8, R8, S11, and R11 may form a second "T" type attenuator, and S3, R3, S9, R9, S12, and R12 may form a third "T" type attenuator. Wherein different attenuators may be provided for different attenuation ratios of the radio frequency signal. Here, taking the first "T" type attenuator composed of R1, R7, and R10 as an example, since the circuit configuration is symmetrical, when the input impedance, the output impedance, the load impedance, and the source output impedance of the attenuator are all equal (for example, 50 ohms), the resistance value of R1 and the resistance value of R10 are equal. The resistance values of R1, R7 and R10 may be determined by calculating or searching the corresponding resistance parameter table according to a formula under the condition that the attenuation ratio is known. Specifically, the larger the decay ratio, the larger the resistance values of R1 and R10, and the smaller the resistance value of R7.

It is to be noted that the attenuation module 10 in the rf attenuation circuit 100 shown in fig. 8 includes 9 resistors and 9 switches, and has the same hardware amount as the rf attenuation circuit in fig. 1. Similarly, the equivalent circuit analysis is performed for the radio frequency attenuation circuit 100 in fig. 8 in the bypass mode. Referring to fig. 9, fig. 9 is an equivalent circuit diagram of the rf attenuation circuit in the bypass mode. Since the bypass switch 30 is in the closed state, it can be equivalently the resistor R20, and the switches S1 to S3, S7 to S12 are all in the open state, and thus can be equivalently the capacitors C1 to C3, C7 to C12. For simplicity of calculation, let c1=c2=c3=c7=c8=c9=c10=c11=c12=c, r7=r8=r9, r1=r2=r3=r10=r11=r12,and +.>When the influence of the equivalent resistance R20 of the bypass switch 30 on the circuit is ignored, the ratio of the B terminal voltage to the a terminal voltage is:

therefore, in the case where the voltages at the a terminals are the same, the ratio of the voltages at the B terminals and the a terminals corresponding to the radio frequency attenuating circuit 100 in fig. 8 is smaller than the ratio of the voltages at the B terminals and the a terminals corresponding to the radio frequency attenuating circuit in fig. 1. That is, the topology employing the radio frequency attenuation circuit 100 of fig. 8 may have less signal leakage in bypass mode with the same amount of hardware. Therefore, compared with the hardware circuit in the prior art, the radio frequency attenuation circuit provided in the application has smaller leakage to radio frequency signals in a bypass state.

In some possible embodiments, the attenuation module 10 may further include a third control switch 181 and a fourth control switch 183. Referring to fig. 10, the third control switch 181 is connected between the first signal terminal 110 and the first terminal 134 of the first attenuation unit 130. The fourth control switch 183 is connected between the second signal terminal 120 and the second terminal 176 of the fourth attenuation unit 170. Specifically, the third control switch 181 and the fourth control switch 183 may be MOS transistors, and the control module 50 is further connected to the third control switch 181 and the fourth control switch 183, for example, the control module 50 may be respectively connected to gates of the MOS transistors, for controlling the working states of the MOS transistors. In this embodiment, when the rf attenuation circuit 100 operates in the bypass mode, the third control switch 181 and the fourth control switch 183 are both in an off state; conversely, when the rf attenuation circuit 100 is operating in the access mode, the third control switch 181 and the fourth control switch 183 are both in a closed state.

Referring to fig. 11, fig. 11 is a schematic diagram illustrating signal attenuation of the rf attenuation circuits shown in fig. 1, 8 and 10 in a bypass mode, respectively. The first curve in fig. 11 is a signal attenuation trend of the radio frequency attenuation circuit in fig. 1 in the bypass mode, the second curve is a signal attenuation trend of the radio frequency attenuation circuit in fig. 8 in the bypass mode, and the third curve is a signal attenuation trend of the radio frequency attenuation circuit in fig. 10 in the bypass mode. As is apparent from fig. 11, the new topology of the rf attenuation circuit 100 in fig. 8 and 10 can have smaller signal leakage in the bypass mode, i.e., the rf attenuation circuit 100 has smaller insertion loss when inputting rf signals of different frequencies, compared to the prior art (i.e., fig. 1). In addition, when the radio frequency signals of different frequencies are input, the signal insertion loss of the radio frequency attenuation circuit 100 in fig. 10 is smaller than that of the radio frequency attenuation circuit 100 in fig. 8. That is, in the case of adding the third control switch 181 and the fourth control switch 183, the radio frequency attenuation circuit 100 in the bypass mode can have less signal leakage to the radio frequency signal.

Referring to fig. 12, the embodiment of the present application further provides a radio frequency module 200. The rf module 200 is configured with the rf attenuation circuit 100 described above. The rf module 200 is a component that integrates two or more discrete devices such as an rf switch, a low noise amplifier, a filter, a duplexer, a power amplifier, etc. into one independent module, thereby improving the integration level and hardware performance and miniaturizing the volume. Specifically, the radio frequency module 200 may be applied to 4G and 5G communication devices such as smart phones, tablet computers, smart watches, and the like.

The embodiment of the application provides a radio frequency attenuation circuit 100 and a radio frequency module 200 provided with the radio frequency attenuation circuit 100. The radio frequency attenuation circuit 100 includes an attenuation module 10, a bypass switch 30, and a control module 50. The attenuation module 10 includes a first signal terminal 110, a second signal terminal 120, a first attenuation unit 130, and a second attenuation unit 140. The first attenuation unit 130 includes a first end 134, a second end 136, and N first attenuation branches 132. The first end 134 of the first attenuation unit 130 is connected to the first signal end 110, and the second end 136 of the first attenuation unit 130 is connected to the second signal end 120; one end of the first attenuation branch 132 is connected to the first end 134 of the first attenuation unit 130, and the other end is connected to the second end 136 of the first attenuation unit 130, where n is greater than 1. The second attenuation unit 140 includes N second attenuation branches 142, where one end of the second attenuation branch 142 is connected to the second end 136 of the first attenuation unit 130, and the other end is grounded. The bypass switch 30 is connected to the first signal terminal 110 and the second signal terminal 120 of the attenuation module 10. The control module 50 is connected to the bypass switch 30.

Because the first attenuation unit 130 and the second attenuation unit 140 in the radio frequency attenuation circuit 100 provided in the present application each include a plurality of branches connected in parallel with each other, when the radio frequency attenuation circuit 100 works in the bypass mode, the equivalent capacitance value of the parasitic capacitance of the plurality of parallel branches is smaller than that of the parasitic capacitance in the prior art, so that the attenuation degree of the radio frequency attenuation circuit 100 to the radio frequency signal is smaller than that of the radio frequency attenuation circuit in the prior art, that is, the topology structure of the radio frequency attenuation circuit 100 provided in the present application can have smaller signal leakage in the bypass mode.

In this specification, certain terms are used throughout the description and claims to refer to particular components. Those of skill in the art will appreciate that a hardware manufacturer may refer to the same component by different names. The description and claims do not take the difference in name as a way of distinguishing between components, but rather take the difference in functionality of the components as a criterion for distinguishing. As used throughout the specification and claims, the word "comprise" and "comprises" are to be construed as "including, but not limited to"; by "substantially" is meant that a person skilled in the art can solve the technical problem within a certain error range, essentially achieving the technical effect.

In the description of the present application, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "inner," and the like indicate an orientation or a positional relationship based on that shown in the drawings, and are merely for convenience of description of the present application, but do not indicate or imply that the apparatus or element in question must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application.

In this application, the terms "mounted," "connected," "secured," and the like are to be construed broadly, unless otherwise specifically indicated or defined. For example, the connection can be fixed connection, detachable connection or integral connection; can be mechanically or electrically connected; the connection may be direct, indirect via an intermediate medium, or communication between two elements, or only surface contact. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless explicitly defined otherwise.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, one of ordinary skill in the art will appreciate that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not drive the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (10)

1. A radio frequency attenuation circuit, comprising:

the attenuation module comprises a first signal end, a second signal end, a first attenuation unit and a second attenuation unit;

the first attenuation unit comprises a first end, a second end and N first attenuation branches;

the first end of the first attenuation unit is connected with the first signal end, and the second end of the first attenuation unit is connected with the second signal end; one end of the first attenuation branch is connected with the first end of the first attenuation unit, the other end of the first attenuation branch is connected with the second end of the first attenuation unit, and N is larger than 1;

the second attenuation unit comprises N second attenuation branches, one end of each second attenuation branch is connected to the second end of the corresponding first attenuation unit, and the other end of each second attenuation branch is grounded;

the bypass switch is connected with the first signal end and the second signal end of the attenuation module; and

and the control module is connected with the bypass switch.

2. The radio frequency attenuation circuit according to claim 1, wherein the first attenuation branch circuit comprises a first attenuation resistor and a first attenuation switch, one end formed by connecting the first attenuation resistor and the first attenuation switch in series is connected to the first end of the first attenuation unit, and the other end is connected to the second end of the first attenuation unit; the resistance values of N first attenuation resistors included in the N first attenuation branches are different;

the control module is also connected with N first attenuation switches included in N first attenuation branches.

3. The radio frequency attenuation circuit according to claim 1, wherein the second attenuation branch circuit comprises a second attenuation resistor and a second attenuation switch, one end formed by connecting the second attenuation resistor and the second attenuation switch in series is connected to the second end of the first attenuation unit, and the other end is grounded; the resistance values of N second attenuation resistors included in the N second attenuation branches are different;

the control module is also connected with N second attenuation switches included in N second attenuation branches.

4. A radio frequency attenuation circuit according to any one of claims 1 to 3, wherein the attenuation module further comprises a third attenuation unit; the third attenuation unit comprises N third attenuation branches, one end of each third attenuation branch is connected to the first end of the first attenuation unit, and the other end of each third attenuation branch is grounded.

5. The radio frequency attenuation circuit according to claim 4, wherein the third attenuation branch circuit comprises a third attenuation resistor and a third attenuation switch, one end formed by connecting the third attenuation resistor and the third attenuation switch in series is connected to the first end of the first attenuation unit, and the other end is grounded; the resistance values of the N third attenuation resistors included in the N third attenuation branches are different;

the control module is also connected with N third attenuation switches included in N third attenuation branches.

6. The radio frequency attenuation circuit of claim 4, wherein the attenuation module further comprises a first control switch and a second control switch; the first control switch is connected between the first signal end and the first end of the first attenuation unit; the second control switch is connected between the second signal end and the second end of the first attenuation unit;

the control module is also connected to the first control switch and the second control switch.

7. A radio frequency attenuation circuit according to any one of claims 1 to 3, wherein the attenuation module further comprises a fourth attenuation unit; the fourth attenuation unit comprises a first end, a second end and N fourth attenuation branches, the first end of the fourth attenuation unit is connected with the second end of the first attenuation unit, and the second end of the fourth attenuation unit is connected with the second signal end;

one end of the fourth attenuation branch is connected to the first end of the fourth attenuation unit, and the other end of the fourth attenuation branch is connected to the second end of the fourth attenuation unit.

8. The radio frequency attenuation circuit according to claim 7, wherein the fourth attenuation branch comprises a fourth attenuation resistor and a fourth attenuation switch, one end formed by connecting the fourth attenuation resistor and the fourth attenuation switch in series is connected to the first end of the fourth attenuation unit, and the other end is connected to the second end of the fourth attenuation unit; the resistance values of the N fourth attenuation resistors included in the N fourth attenuation branches are different;

the control module is also connected with N fourth attenuation switches included in N fourth attenuation branches.

9. The radio frequency attenuation circuit of claim 7, wherein the attenuation module further comprises a third control switch and a fourth control switch; the third control switch is connected between the first signal end and the first end of the first attenuation unit; the fourth control switch is connected between the second signal end and the second end of the fourth attenuation unit;

the control module is also connected to the third control switch and the fourth control switch.

10. A radio frequency module, comprising: a radio frequency attenuation circuit according to any one of claims 1 to 9.