Radio Frequency Front-End Module

Abstract

The present invention provides a radio frequency front-end module, which includes a first matching circuit, a first-stage power amplifier circuit, a coupler, a first radio frequency switch, a radio frequency main path, an attenuation path, a second radio frequency switch, a second matching circuit, a second-stage power amplifier circuit, a third matching circuit, a power detection circuit, a low-pass filter, a first operational amplifier, and a hysteresis comparator; the hysteresis comparator is used to control the input end of the first radio frequency switch to be connected to the first output end or the second output end of the first radio frequency switch, and at the same time is used to control the first input end or the second input end of the second radio frequency switch to be connected to the output end of the second radio frequency switch. The radio frequency front-end module in the present invention can ensure the normal output of radio frequency signals on the premise of ensuring that the power amplifier circuit will not be damaged, and at the same time will not cause distortion of the subsequent-stage output signal due to the reduction of the bias voltage.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and in particular, to a radio frequency front-end module. Background Art

[0002] In wireless communication devices such as mobile terminals and routers, a radio frequency power amplifier is used to amplify a radio frequency small signal output by a front-stage circuit, such as a radio frequency small signal output by a modulation circuit. When the radio frequency small signal is amplified to a rated power by the radio frequency power amplifier, it will be output to an antenna, so as to transmit the amplified radio frequency signal through the antenna.

[0003] For wireless products such as mobile phones and routers, the power of the maximum input signal of the radio frequency power amplifier is usually below 5 dBm, and the maximum gain of the radio frequency power amplifier is about 30 dB. However, in some abnormal situations, the input power of the radio frequency power amplifier can reach 10 - 20 dBm. At this time, it is very easy to cause the radio frequency power amplifier to be damaged, thus making the entire product ineffective.

[0004] The existing technology to avoid damage to the radio frequency power amplifier due to a large input power is to turn off or reduce the bias voltage of the subsequent stage by detecting the magnitude of the input power. Although this method can avoid damage to the radio frequency power amplifier, this method will cause the radio frequency signal not to be output, or the output signal of the subsequent stage to be severely distorted due to the reduction of the bias voltage. Summary of the Invention

[0005] In view of the above deficiencies of the prior art, the present invention proposes a radio frequency front-end module to solve the problem that the method of turning off or reducing the bias voltage of the subsequent stage by detecting the magnitude of the input power in the prior art to avoid damage to the radio frequency power amplifier will cause the radio frequency signal not to be output, or the output signal of the subsequent stage to be severely distorted due to the reduction of the bias voltage.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a radio frequency front-end module, which includes a first matching circuit, a first-stage power amplification circuit, a coupler, a first radio frequency switch, a radio frequency main path, an attenuation path, a second radio frequency switch, a second matching circuit, a second-stage power amplification circuit, a third matching circuit, a power detection circuit, a low-pass filter, a first operational amplifier, and a hysteresis comparator;

[0008] The input end of the first matching circuit is used to receive a radio frequency signal;

[0009] The input end of the first-stage power amplification circuit is connected to the output end of the first matching circuit;

[0010] The input end of the coupler is connected to the output end of the first-stage power amplifier circuit;

[0011] The input end of the first RF switch is connected to the output end of the coupler. The first output end of the first RF switch is connected to the first end of the RF main path, and the second output end of the first RF switch is connected to the first end of the attenuation path;

[0012] The attenuation path is used for attenuating the power of the received RF signal;

[0013] The first input end of the second RF switch is connected to the second end of the RF main path, and the second input end of the second RF switch is connected to the second end of the attenuation path;

[0014] The input end of the second matching circuit is connected to the output end of the second RF switch;

[0015] The input end of the second-stage power amplifier circuit is connected to the output end of the second matching circuit;

[0016] The input end of the third matching circuit is connected to the output end of the second-stage power amplifier circuit, and the output end of the third matching circuit is used for outputting an RF signal;

[0017] The input end of the power detection circuit is connected to the coupling end of the coupler, and is used for converting the received RF signal into a DC voltage;

[0018] The input end of the low-pass filter is connected to the output end of the power detection circuit, and is used for filtering out the received RF signal component and the baseband envelope signal;

[0019] The input end of the first operational amplifier is connected to the output end of the low-pass filter;

[0020] The first input end of the hysteresis comparator is connected to the output end of the first operational amplifier. The second input end of the hysteresis comparator is used for accessing a reference signal. The output end of the hysteresis comparator is respectively connected to the control end of the first RF switch and the control end of the second RF switch. The hysteresis comparator is used for outputting a level signal according to the received voltage signal and the reference signal to control the input end of the first RF switch to be connected to the first output end or the second output end of the first RF switch, and to control the first input end or the second input end of the second RF switch to be connected to the output end of the second RF switch.

[0021] Preferably, the coupler includes a first microstrip line, a second microstrip line coupled to the first microstrip line, and a first resistor;

[0022] The first end of the first microstrip line serves as the input end of the coupler, and the second end of the first microstrip line serves as the output end of the coupler;

[0023] The first end of the second microstrip line serves as the coupling end of the coupler;

[0024] The first end of the first resistor is connected to the second end of the second microstrip line, and the second end of the first resistor is grounded.

[0025] Preferably, the coupler includes a second resistor; the first end of the second resistor is connected to the output end of the first-stage power amplifier circuit, and the second end of the second resistor serves as the coupling end of the coupler; the output end of the first-stage power amplifier circuit serves as the input end of the coupler, and the input end of the first RF switch serves as the output end of the coupler.

[0026] Preferably, the first RF switch is a first single-pole double-throw switch; the second RF switch is a second single-pole double-throw switch;

[0027] The common end of the first single-pole double-throw switch serves as the input end of the first RF switch, the first connection end of the first single-pole double-throw switch serves as the first output end of the first RF switch, the second connection end of the first single-pole double-throw switch serves as the second output end of the first RF switch, and the control end of the first single-pole double-throw switch serves as the control end of the first RF switch;

[0028] The first connection end of the second single-pole double-throw switch serves as the first input end of the second RF switch, the second connection end of the second single-pole double-throw switch serves as the second input end of the second RF switch, the common end of the second single-pole double-throw switch serves as the output end of the second RF switch, and the control end of the second single-pole double-throw switch serves as the control end of the second RF switch.

[0029] Preferably, the attenuation path includes a third resistor, a fourth resistor, and a fifth resistor;

[0030] The first end of the third resistor serves as the first end of the attenuation path, and the second end of the third resistor is grounded; the first end of the fourth resistor is connected to the first end of the third resistor, and the second end of the fourth resistor serves as the second end of the attenuation path; the first end of the fifth resistor is connected to the second end of the fourth resistor, and the second end of the fifth resistor is grounded.

[0031] Preferably, the attenuation path includes a third resistor, a fourth resistor, and a fifth resistor;

[0032] The first end of the third resistor serves as the first end of the attenuation path; the first end of the fourth resistor is connected to the second end of the third resistor, and the second end of the fourth resistor is grounded; the first end of the fifth resistor is connected to the first end of the fourth resistor, and the second end of the fifth resistor serves as the second end of the attenuation path.

[0033] Preferably, the low-pass filter includes a sixth resistor and a capacitor;

[0034] The first end of the sixth resistor serves as the input end of the low-pass filter, and the second end of the sixth resistor serves as the output end of the low-pass filter;

[0035] The first end of the capacitor is connected to the second end of the sixth resistor, and the second end of the capacitor is grounded.

[0036] Preferably, the hysteresis comparator includes a seventh resistor, a second operational amplifier, and an eighth resistor;

[0037] The first end of the seventh resistor serves as the first input end of the hysteresis comparator;

[0038] The non-inverting input end of the second operational amplifier is connected to the second end of the seventh resistor, and the output end of the second operational amplifier serves as the output end of the hysteresis comparator;

[0039] The first end of the eighth resistor is connected to the second end of the seventh resistor, and the second end of the eighth resistor is connected to the output end of the second operational amplifier.

[0040] Preferably, the second output end of the first RF switch, the control end of the first RF switch, the attenuation path, the input end of the second RF switch, the control end of the second RF switch, and the hysteresis comparator each include a plurality and the same number, and the amounts of power attenuation of the plurality of attenuation paths are all different;

[0041] The second output end of each first RF switch is connected to the first end of an attenuation path; the second input end of each first RF switch is connected to the second end of an attenuation path; the output end of each hysteresis comparator is respectively connected to a control end of the first RF switch and a control end of the second RF switch, for controlling the input end of the first RF switch to communicate with one of the second output ends of the first RF switch, and at the same time for controlling one of the second input ends of the second RF switch to communicate with the output end of the second RF switch.

[0042] Compared with the prior art, in the RF front-end module of the present invention, by designing a first matching circuit, a first-stage power amplifier circuit, a coupler, a first RF switch, a main RF path, an attenuation path, a second RF switch, a second matching circuit, a second-stage power amplifier circuit, a third matching circuit, a power detection circuit, a low-pass filter, a first operational amplifier, and a hysteresis comparator, and defining that the hysteresis comparator is used to output a level signal according to the received voltage signal and the reference signal to control the input end of the first RF switch to be connected to the first output end or the second output end of the first RF switch, and to control the first input end or the second input end of the second RF switch to be connected to the output end of the second RF switch. In this way, when the input power is large, the attenuation path can be selected through the hysteresis comparator to attenuate the input power within the maximum input power of the power amplifier circuit, thereby avoiding damage to the power amplifier circuit, and there is no need to turn off or reduce the bias voltage of the subsequent stage, ensuring the normal output of the RF signal, and at the same time, the output signal of the subsequent stage will not be distorted due to the reduction of the bias voltage. Description of the Drawings

[0043] The present invention will be described in detail below with reference to the drawings. Through the detailed description in combination with the following drawings, the above or other aspects of the present invention will become clearer and easier to understand. In the drawings:

[0044] Figure 1 is the circuit schematic diagram of the first RF front-end module provided by the embodiment of the present invention;

[0045] Figure 2 is the circuit schematic diagram of the first coupler in the first RF front-end module provided by the embodiment of the present invention;

[0046] Figure 3 is the circuit schematic diagram of the second coupler in the first RF front-end module provided by the embodiment of the present invention;

[0047] Figure 4 is the circuit schematic diagram of another attenuation path in the first RF front-end module provided by the embodiment of the present invention;

[0048] Figure 5 is the circuit schematic diagram of the second RF front-end module provided by the embodiment of the present invention. Detailed Embodiments

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification, claims or drawings of this application are used to distinguish different objects and not to describe a specific order.

[0050] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in connection with the embodiments can be included in at least one embodiment of this application. The phrase does not necessarily refer to the same embodiment at each occurrence in the specification, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0052] Embodiment 1

[0053] An embodiment of the present invention provides a radio frequency front-end module 100, as shown in combination with Figures 1 to 4 It includes a first matching circuit 1, a first-stage power amplifier circuit 2, a coupler 3, a first radio frequency switch SW1, a radio frequency main path 4, an attenuation path 5, a second radio frequency switch SW2, a second matching circuit 6, a second-stage power amplifier circuit 7, a third matching circuit 8, a power detection circuit 9, a low-pass filter 10, a first operational amplifier Amp1, and a hysteresis comparator 11.

[0054] Among them, the input end of the first matching circuit 1 is used to receive a radio frequency signal TXIn.

[0055] The input end of the first-stage power amplifier circuit 2 is connected to the output end of the first matching circuit 1.

[0056] The input end of the coupler 3 is connected to the output end of the first-stage power amplifier circuit 2.

[0057] The input end of the first radio frequency switch SW1 is connected to the output end of the coupler 3. The first output end of the first radio frequency switch SW1 is connected to the first end of the radio frequency main path 4. The second output end of the first radio frequency switch SW1 is connected to the first end of the attenuation path 5.

[0058] The attenuation path 5 is used to attenuate the power of the received radio frequency signal.

[0059] The first input end of the second radio frequency switch SW2 is connected to the second end of the radio frequency main path 4. The second input end of the second radio frequency switch SW2 is connected to the second end of the attenuation path 5.

[0060] The input end of the second matching circuit 6 is connected to the output end of the second radio frequency switch SW2.

[0061] The input end of the two-stage power amplifier circuit 7 is connected to the output end of the second matching circuit 6.

[0062] The input end of the third matching circuit 8 is connected to the output end of the two-stage power amplifier circuit 7. The output end of the third matching circuit 8 is used to output the radio frequency signal TXOut.

[0063] The input end of the power detection circuit 9 is connected to the coupling end of the coupler 3, and is used to convert the received radio frequency signal into a DC voltage.

[0064] The input end of the low-pass filter 10 is connected to the output end of the power detection circuit 9, and is used to filter out the received radio frequency signal component and the baseband envelope signal, that is, to filter out the high-frequency component.

[0065] The input end of the first operational amplifier Amp1 is connected to the output end of the low-pass filter 10.

[0066] The first input end of the hysteresis comparator 11 is connected to the output end of the first operational amplifier Amp1. The second input end of the hysteresis comparator 11 is used to access the reference signal. The output end of the hysteresis comparator 11 is respectively connected to the control ends of the first radio frequency switch SW1 and the second radio frequency switch SW2. The hysteresis comparator 11 is used to output a level signal according to the received voltage signal and the reference signal, so as to control the input end of the first radio frequency switch SW1 to be connected to the first output end or the second output end of the first radio frequency switch SW1, and to control the first input end or the second input end of the second radio frequency switch SW2 to be connected to the output end of the second radio frequency switch SW2.

[0067] As Figure 2 shown, as one of the design methods of the coupler 3, the coupler 3 includes a first microstrip line 31, a second microstrip line 32 coupled to the first microstrip line 31, and a first resistor R1.

[0068] The first end of the first microstrip line 31 serves as the input end of the coupler 3, and the second end of the first microstrip line 31 serves as the output end of the coupler 3.

[0069] The first end of the second microstrip line 32 serves as the coupling end of the coupler 3.

[0070] The first end of the first resistor R1 is connected to the second end of the second microstrip line 32, and the second end of the first resistor R1 is grounded.

[0071] As Figure 3 shown, as another design method of the coupler 3, the coupler 3 includes a second resistor R2; the first end of the second resistor R2 is connected to the output end of the first-stage power amplifier circuit 2, and the second end of the second resistor R2 serves as the coupling end of the coupler 3; the output end of the first-stage power amplifier circuit 2 serves as the input end of the coupler 3, and the input end of the first radio frequency switch SW1 serves as the output end of the coupler 3. This design method of the coupler 3 has the advantages of simple circuit, small chip area occupation, and flexible adjustment compared with the above-mentioned design method of the coupler 3.

[0072] In this embodiment, as Figure 1 shown, the first radio frequency switch SW1 is a first single-pole double-throw switch; the second radio frequency switch SW2 is a second single-pole double-throw switch.

[0073] The common end of the first single-pole double-throw switch serves as the input end of the first radio frequency switch SW1, the first connection end of the first single-pole double-throw switch serves as the first output end of the first radio frequency switch SW1, the second connection end of the first single-pole double-throw switch serves as the second output end of the first radio frequency switch SW1, and the control end of the first single-pole double-throw switch serves as the control end of the first radio frequency switch SW1.

[0074] The first connection end of the second single-pole double-throw switch serves as the first input end of the second radio frequency switch SW2, the second connection end of the second single-pole double-throw switch serves as the second input end of the second radio frequency switch SW2, the common end of the second single-pole double-throw switch serves as the output end of the second radio frequency switch SW2, and the control end of the second single-pole double-throw switch serves as the control end of the second radio frequency switch SW2.

[0075] In this embodiment, the attenuation path 5 includes a third resistor R3, a fourth resistor R4, and a fifth resistor R5.

[0076] As Figure 1As shown in the figure, as one of the design methods of the attenuation path 5, the first end of the third resistor R3 serves as the first end of the attenuation path 5, and the second end of the third resistor R3 is grounded; the first end of the fourth resistor R4 is connected to the first end of the third resistor R3, and the second end of the fourth resistor R4 serves as the second end of the attenuation path 5; the first end of the fifth resistor R5 is connected to the second end of the fourth resistor R4, and the second end of the fifth resistor R5 is grounded. The attenuation path 5 of this design method can be understood as a π-type attenuator.

[0077] As Figure 4 shown in the figure, as another design method of the attenuation path 5, the first end of the third resistor R3 serves as the first end of the attenuation path 5; the first end of the fourth resistor R4 is connected to the second end of the third resistor R3, and the second end of the fourth resistor R4 is grounded; the first end of the fifth resistor R5 is connected to the first end of the fourth resistor R4, and the second end of the fifth resistor R5 serves as the second end of the attenuation path 5. The attenuation path 5 of this design method can be understood as a T-type attenuator.

[0078] In this embodiment, as Figure 1 shown in the figure, the low-pass filter 10 includes a sixth resistor R6 and a capacitor C.

[0079] The first end of the sixth resistor R6 serves as the input end of the low-pass filter 10, and the second end of the sixth resistor R6 serves as the output end of the low-pass filter 10.

[0080] The first end of the capacitor C is connected to the second end of the sixth resistor R6, and the second end of the capacitor C is grounded.

[0081] In this embodiment, as Figure 1 shown in the figure, the hysteresis comparator 11 includes a seventh resistor R7, a second operational amplifier, and an eighth resistor R8.

[0082] The first end of the seventh resistor R7 serves as the first input end of the hysteresis comparator 11.

[0083] The non-inverting input end of the second operational amplifier is connected to the second end of the seventh resistor R7, and the output end of the second operational amplifier serves as the output end of the hysteresis comparator 11.

[0084] The first end of the eighth resistor R8 is connected to the second end of the seventh resistor R7, and the second end of the eighth resistor R8 is connected to the output end of the second operational amplifier.

[0085] In this embodiment, the first operational amplifier Amp1 of the RF front-end module 100, also known as the low-frequency amplifier, is used to buffer and amplify the received signal and has the characteristic of high input impedance. The hysteresis comparator 11 can avoid the ping-pong effect of the comparator. The reference signal connected to the second input terminal of the hysteresis comparator 11 can be a voltage signal or a level signal, which can be provided by an internally designed low-dropout regulator (LDO) or in other ways.

[0086] In this embodiment, after the power detection circuit 9 of the RF front-end module 100 converts the RF signal into a DC voltage, the DC voltage is Vdet1. The DC voltage output after being buffered and amplified by the first operational amplifier Amp1 is Vdet2. The reference signal connected to the second input terminal of the hysteresis comparator 11 is Vref.

[0087] When Vdet2 is greater than Vh, the hysteresis comparator 11 outputs a high-level signal Voh; when Vdet2 is less than V1, the hysteresis comparator 11 outputs a low-level signal Vol. Among them, Vh and V1 are obtained by the following formulas respectively:

[0088] ;

[0089] ;

[0090] It can be seen that by modifying the reference voltage Vref, the decision threshold can be adjusted, that is, whether the hysteresis comparator 11 outputs a high-level signal or a low-level signal.

[0091] Set the common terminal of the first single-pole double-throw switch as RF11, the first connection terminal of the first single-pole double-throw switch as RF12, the second connection terminal of the first single-pole double-throw switch as RF13, the common terminal of the second single-pole double-throw switch as RF21, the first connection terminal of the second single-pole double-throw switch as RF22, the second connection terminal of the second single-pole double-throw switch as RF33, and the level signal output by the hysteresis comparator 11 as CNT.

[0092] When CNT is a low-level signal, RF11 is connected to RF12, RF13 is not connected, RF22 is connected to RF21, and R23 is not connected. At this time, the RF signal is transmitted from RF12 to RF22 and output to RF21.

[0093] When CNT is a high-level signal, RF11 is connected to RF13, RF12 is not connected, RF23 is connected to RF21, and R22 is not connected. At this time, the RF signal is transmitted from RF13 to the attenuation path 5. The attenuation path 5 attenuates the power of the RF signal to a certain extent, such as 20 Db, and then outputs it to RF21 through RF23.

[0094] When a high-power signal is input to the RF front-end module 100 in this embodiment, by switching to the attenuation path 5, the subsequent-stage amplifier can be protected, and at the same time, the transmitted RF signal can continue to be transmitted without interruption.

[0095] Compared with the prior art, the RF front-end module 100 in this embodiment is designed with a first matching circuit 1, a first-stage power amplifier circuit 2, a coupler 3, a first RF switch SW1, an RF main path 4, an attenuation path 5, a second RF switch SW2, a second matching circuit 6, a second-stage power amplifier circuit 7, a third matching circuit 8, a power detection circuit 9, a low-pass filter 10, a first operational amplifier Amp1, and a hysteresis comparator 11. The hysteresis comparator 11 is defined to output a level signal according to the received voltage signal and the reference signal to control the input end of the first RF switch SW1 to be connected to the first output end or the second output end of the first RF switch SW1, and to control the first input end or the second input end of the second RF switch SW2 to be connected to the output end of the second RF switch SW2. In this way, when the input power is large, the attenuation path 5 can be selected by the hysteresis comparator 11 to attenuate the input power within the maximum input power of the power amplifier circuit, thereby avoiding damage to the power amplifier circuit, and there is no need to turn off or reduce the subsequent-stage bias voltage, ensuring the normal output of the RF signal, and at the same time, the subsequent-stage output signal will not be distorted due to the reduction of the bias voltage.

[0096] Embodiment Two

[0097] The difference between the RF front-end module 200 in this embodiment and the RF front-end module 100 in the first embodiment above is that in the RF front-end module 200 of this embodiment, the second output end of the first RF switch SW1, the control end of the first RF switch SW1, the attenuation path 5, the input end of the second RF switch SW2, the control end of the second RF switch SW2, and the hysteresis comparator 11 each include a plurality and the same number, and the amounts of power attenuation of the plurality of attenuation paths 5 are all different.

[0098] The second output end of each first RF switch SW1 is connected to the first end of an attenuation path 5; the second input end of each first RF switch SW1 is connected to the second end of an attenuation path 5; the output end of each hysteresis comparator 11 is respectively connected to a control end of the first RF switch SW1 and a control end of the second RF switch SW2, for controlling the input end of the first RF switch SW1 to be connected to one of the second output ends of the first RF switch SW1, and at the same time for controlling one of the second input ends of the second RF switch SW2 to be connected to the output end of the second RF switch SW2.

[0099] This design method can make the power control more flexible compared with the design method of the first embodiment above.

[0100] As Figure 5 shown, the second output terminal, the control terminal of the first radio frequency switch SW1, the attenuation path 5, the input terminal of the second radio frequency switch SW2, the control terminal of the second radio frequency switch SW2, and the hysteresis comparator 11 in this embodiment each include two.

[0101] That is, the attenuation path 5 includes two, namely the first attenuation path 51 and the second attenuation path 52; the hysteresis comparator 11 includes two, namely the first hysteresis comparator 111 and the second hysteresis comparator 112.

[0102] The first radio frequency switch SW1 is a first single-pole triple-throw switch; the second radio frequency switch SW2 is a second single-pole triple-throw switch.

[0103] The common terminal of the first single-pole triple-throw switch serves as the input terminal of the first radio frequency switch SW1, the first connection terminal of the first single-pole triple-throw switch serves as the first output terminal of the first radio frequency switch SW1, the second connection terminal of the first single-pole triple-throw switch serves as one of the second output terminals of the first radio frequency switch SW1, the third connection terminal of the first single-pole triple-throw switch serves as the other second output terminal of the first radio frequency switch SW1, the first control terminal of the first single-pole triple-throw switch serves as one of the control terminals of the first radio frequency switch SW1, and the second control terminal of the first single-pole triple-throw switch serves as the other control terminal of the first radio frequency switch SW1.

[0104] The first connection terminal of the second single-pole triple-throw switch serves as the first input terminal of the second radio frequency switch SW2, the second connection terminal of the second single-pole triple-throw switch serves as one of the second input terminals of the second radio frequency switch SW2, the third connection terminal of the second single-pole triple-throw switch serves as the other second input terminal of the second radio frequency switch SW2, the common terminal of the second single-pole triple-throw switch serves as the output terminal of the second radio frequency switch SW2, the first control terminal of the second single-pole triple-throw switch serves as one of the control terminals of the second radio frequency switch SW2, and the second control terminal of the second single-pole triple-throw switch serves as the other control terminal of the second radio frequency switch SW2.

[0105] Set the common terminal of the first single-pole triple-throw switch as RF31, the first connection terminal of the first single-pole triple-throw switch as RF32, the second connection terminal of the first single-pole triple-throw switch as RF33, the third connection terminal of the first single-pole triple-throw switch as RF34, the common terminal of the second single-pole triple-throw switch as RF41, the first connection terminal of the second single-pole triple-throw switch as RF42, the second connection terminal of the second single-pole triple-throw switch as RF43, the third connection terminal of the second single-pole triple-throw switch as RF44, the level signal output by the first hysteresis comparator 11 as CNT1, the reference signal connected thereto as Vref1, the level signal output by the second hysteresis comparator 11 as CNT2, the reference signal connected thereto as Vref2, and Vref1 is less than Vref2, the attenuation amount of the first attenuation path 5 is Att1, the attenuation amount of the second attenuation path 5 is Att2, and Att1 is less than Att2.

[0106] The control logic truth tables of the first single-pole triple-throw switch and the second single-pole triple-throw switch are as follows:

[0107]

[0108] When a low-power signal is input, both CNT1 and CNT2 output low-level signals. RF31 is connected to RF32, then connected to RF42 and transmitted to RF41, and output after being amplified by the two-stage power amplifier circuit 7.

[0109] When a medium-power signal is input, CNT1 outputs a high-level signal, CNT2 outputs a low-level signal. RF31 is connected to RF33, then after power attenuation through the first attenuation path 5, it is connected to RF43 and transmitted to RF41, and output after being amplified by the two-stage power amplifier circuit 7.

[0110] When a high-power signal is input, both CNT1 and CNT2 output high-level signals. RF31 is connected to RF34, then after power attenuation through the second attenuation path 5, it is connected to RF44 and transmitted to RF41, and output after being amplified by the two-stage power amplifier circuit 7.

[0111] Since the principle of the RF front-end module 200 in this embodiment is the same as or similar to that of the RF front-end module 100 in the first embodiment above, the RF front-end module 200 in this embodiment can also achieve the technical effects achieved by the RF front-end module 100 in the first embodiment above, which will not be elaborated here.

[0112] It should be noted that the various embodiments described above with reference to the accompanying drawings are only used to illustrate the present invention and not to limit the scope of the present invention. Those of ordinary skill in the art should understand that any modification or equivalent replacement made to the present invention without departing from the spirit and scope of the present invention shall be covered within the scope of the present invention. In addition, unless otherwise indicated by the context, words in the singular form include the plural form and vice versa. Additionally, unless otherwise specified, all or part of any embodiment can be used in combination with all or part of any other embodiment.

Claims

1. A radio frequency front-end module, characterized in that, The RF front-end module includes a first matching circuit, a first-stage power amplifier circuit, a coupler, a first RF switch, a main RF path, an attenuation path, a second RF switch, a second matching circuit, a second-stage power amplifier circuit, a third matching circuit, a power detection circuit, a low-pass filter, a first operational amplifier, and a hysteresis comparator; The input end of the first matching circuit is used to receive RF signals; The input end of the first-stage power amplifier circuit is connected to the output end of the first matching circuit; The input end of the coupler is connected to the output end of the first-stage power amplifier circuit; The input end of the first RF switch is connected to the output end of the coupler. The first output end of the first RF switch is connected to the first end of the main RF path, and the second output end of the first RF switch is connected to the first end of the attenuation path; The attenuation path is used to attenuate the power of the received RF signals; The first input end of the second RF switch is connected to the second end of the main RF path, and the second input end of the second RF switch is connected to the second end of the attenuation path; The input end of the second matching circuit is connected to the output end of the second RF switch; The input end of the second-stage power amplifier circuit is connected to the output end of the second matching circuit; The input end of the third matching circuit is connected to the output end of the second-stage power amplifier circuit, and the output end of the third matching circuit is used to output RF signals; The input end of the power detection circuit is connected to the coupling end of the coupler, and is used to convert the received RF signals into DC voltages; The input end of the low-pass filter is connected to the output end of the power detection circuit, and is used to filter out the received RF signal components and baseband envelope signals; The input end of the first operational amplifier is connected to the output end of the low-pass filter; The first input end of the hysteresis comparator is connected to the output end of the first operational amplifier. The second input end of the hysteresis comparator is used to access a reference signal. The output end of the hysteresis comparator is respectively connected to the control ends of the first RF switch and the second RF switch. The hysteresis comparator is used to output a level signal according to the received voltage signal and the reference signal, so as to control the input end of the first RF switch to be connected to the first output end or the second output end of the first RF switch, and to control the first input end or the second input end of the second RF switch to be connected to the output end of the second RF switch.

2. The RF front-end module according to claim 1, wherein The coupler includes a first microstrip line, a second microstrip line coupled to the first microstrip line, and a first resistor; The first end of the first microstrip line serves as the input end of the coupler, and the second end of the first microstrip line serves as the output end of the coupler; The first end of the second microstrip line serves as the coupling end of the coupler; The first end of the first resistor is connected to the second end of the second microstrip line, and the second end of the first resistor is grounded.

3. The RF front-end module according to claim 1, wherein The coupler includes a second resistor; a first end of the second resistor is connected to an output end of the first-stage power amplifier circuit, and a second end of the second resistor serves as a coupling end of the coupler; the output end of the first-stage power amplifier circuit serves as an input end of the coupler, and an input end of the first RF switch serves as an output end of the coupler.

4. The RF front-end module according to claim 1, wherein The first RF switch is a first single-pole double-throw switch; the second RF switch is a second single-pole double-throw switch. A common end of the first single-pole double-throw switch serves as an input end of the first RF switch, a first connection end of the first single-pole double-throw switch serves as a first output end of the first RF switch, a second connection end of the first single-pole double-throw switch serves as a second output end of the first RF switch, and a control end of the first single-pole double-throw switch serves as a control end of the first RF switch. A first connection end of the second single-pole double-throw switch serves as a first input end of the second RF switch, a second connection end of the second single-pole double-throw switch serves as a second input end of the second RF switch, a common end of the second single-pole double-throw switch serves as an output end of the second RF switch, and a control end of the second single-pole double-throw switch serves as a control end of the second RF switch.

5. The RF front-end module according to claim 1, wherein The attenuation path includes a third resistor, a fourth resistor, and a fifth resistor. A first end of the third resistor serves as a first end of the attenuation path, and a second end of the third resistor is grounded; a first end of the fourth resistor is connected to the first end of the third resistor, and a second end of the fourth resistor serves as a second end of the attenuation path; a first end of the fifth resistor is connected to the second end of the fourth resistor, and a second end of the fifth resistor is grounded.

6. The RF front-end module according to claim 5, characterized in that The attenuation path includes a third resistor, a fourth resistor, and a fifth resistor. A first end of the third resistor serves as a first end of the attenuation path; a first end of the fourth resistor is connected to a second end of the third resistor, and a second end of the fourth resistor is grounded; a first end of the fifth resistor is connected to the first end of the fourth resistor, and a second end of the fifth resistor serves as a second end of the attenuation path.

7. The radio frequency front-end module according to claim 1, wherein The low-pass filter includes a sixth resistor and a capacitor. A first end of the sixth resistor serves as an input end of the low-pass filter, and a second end of the sixth resistor serves as an output end of the low-pass filter. A first end of the capacitor is connected to the second end of the sixth resistor, and a second end of the capacitor is grounded.

8. The RF front-end module according to claim 1, wherein, The hysteresis comparator includes a seventh resistor, a second operational amplifier, and an eighth resistor. A first end of the seventh resistor serves as a first input end of the hysteresis comparator. A non-inverting input end of the second operational amplifier is connected to a second end of the seventh resistor, and an output end of the second operational amplifier serves as an output end of the hysteresis comparator. A first end of the eighth resistor is connected to the second end of the seventh resistor, and a second end of the eighth resistor is connected to the output end of the second operational amplifier.

9. The RF front-end module according to claim 1, wherein, The second output terminal of the first RF switch, the control terminal of the first RF switch, the attenuation path, the input terminal of the second RF switch, the control terminal of the second RF switch, and the hysteresis comparator each include a plurality and the same number, and the amounts of power attenuation of the plurality of attenuation paths are all different from each other; The second output terminal of each first RF switch is connected to one first end of an attenuation path; the second input terminal of each first RF switch is connected to one second end of an attenuation path; the output terminal of each hysteresis comparator is respectively connected to one control terminal of the first RF switch and one control terminal of the second RF switch, and is used for controlling the input terminal of the first RF switch to communicate with one of the second output terminals of the first RF switch, and at the same time for controlling one of the second input terminals of the second RF switch to communicate with the output terminal of the second RF switch.

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