Radio frequency front-end module

Abstract

The invention provides a radio frequency front end module. The circuit comprises 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. The hysteresis comparator is used for controlling the input end of the first radio frequency switch to be communicated with the first output end of the first radio frequency switch or the second output end of the first radio frequency switch; and meanwhile, the control circuit is used for controlling the first input end of the second radio frequency switch or the second input end of the second radio frequency switch to be communicated with the output end of the second radio frequency switch. According to the radio frequency front-end module, on the premise that the power amplification circuit is not damaged, normal output of the radio frequency signal can be ensured, and meanwhile the situation that a post-stage output signal is distorted due to reduction of the bias voltage is avoided.

Description

Technical Field

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

[0002] In wireless communication devices such as mobile terminals and routers, RF power amplifiers are used to amplify small RF signals output by the previous circuit, such as small RF signals output by the modulation circuit. When the small RF signal is amplified to the rated power by the RF power amplifier, it will be output to the antenna to transmit the amplified RF signal through the antenna.

[0003] For wireless products such as mobile phones and routers, the maximum input signal power of the RF power amplifier is usually below 5dBm, and the maximum gain of the RF power amplifier is around 30dB. However, in some abnormal cases, the input power of the RF power amplifier can reach 10-20dBm, which can easily damage the RF power amplifier and make the entire product ineffective.

[0004] The prior art method for avoiding damage to the RF power amplifier due to large input power is to shut down or reduce the subsequent stage bias voltage by detecting the input power. Although this method can avoid damage to the RF power amplifier, it will cause the RF signal to be unable to be output, or the subsequent stage output signal will be severely distorted due to the reduction of the bias voltage. Summary of the invention

[0005] In view of the above shortcomings of the prior art, the present invention proposes a RF front-end module to solve the problem that the prior art method of avoiding damage to the RF power amplifier by detecting the size of the input power to shut down or reduce the subsequent stage bias voltage will cause the RF signal to be unable to be output, or the subsequent stage output signal will be severely distorted due to the reduction of the bias voltage.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: In a first aspect, 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 input end of the first matching circuit is used to receive a radio frequency signal; 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 RF main 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 radio frequency signal; 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; An input end of the second matching circuit is connected to an output end of the second RF switch; The input end of the secondary 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 secondary power amplifier circuit, and the output end of the third matching circuit is used to output a radio frequency signal; The input end of the power detection circuit is connected to the coupling end of the coupler, and is used to convert the received radio frequency signal into a direct current voltage; 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 radio frequency signal component and baseband envelope signal; The input terminal of the first operational amplifier is connected to the output terminal 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 the 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, and 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 of the first RF switch or the second output end of the first RF switch, and control the first input end of the second RF switch or the second input end of the second RF switch to be connected to the output end of the second RF switch.

[0007] Preferably, 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 a coupling end of the coupler; A first end of the first resistor is connected to a second end of the second microstrip line, and a second end of the first resistor is grounded.

[0008] 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.

[0009] Preferably, the first radio frequency switch is a first single-pole double-throw switch; the second radio frequency switch is a second single-pole double-throw switch; The common end of the first single-pole double-throw switch serves as the input end of the first radio frequency switch, the first connection end of the first single-pole double-throw switch serves as the first output end of the first radio frequency switch, the second connection end of the first single-pole double-throw switch serves as the second output end of the first radio frequency switch, and the control end of the first single-pole double-throw switch serves as the control end of the first radio frequency switch; The first connection end of the second single-pole double-throw switch serves as the first input end of the second radio frequency switch, the second connection end of the second single-pole double-throw switch serves as the second input end of the second radio frequency switch, the common end of the second single-pole double-throw switch serves as the output end of the second radio frequency switch, and the control end of the second single-pole double-throw switch serves as the control end of the second radio frequency switch.

[0010] Preferably, the attenuation path includes a third resistor, a fourth resistor and a fifth resistor; 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.

[0011] Preferably, the attenuation path includes a third resistor, a fourth resistor and a fifth resistor; 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.

[0012] Preferably, the low-pass filter comprises a sixth resistor and a capacitor; 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; 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.

[0013] Preferably, the hysteresis comparator comprises a seventh resistor, a second operational amplifier and an eighth resistor; The first end of the seventh resistor serves as the first input end of the hysteresis comparator; The non-inverting input terminal of the second operational amplifier is connected to the second end of the seventh resistor, and the output terminal of the second operational amplifier serves as the output terminal of the hysteresis comparator; 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.

[0014] 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 respectively include a plurality of the same number, and the power attenuation amounts of the plurality of attenuation paths are different; The second output end of each of the first RF switches is connected to the first end of the attenuation path; the second input end of each of the first RF switches is connected to the second end of the attenuation path; the output end of each of the hysteresis comparators is respectively connected to a control end of the first RF switch and a control end of the second RF switch, and is used to control the input end of the first RF switch to be connected to one of the second output ends of the first RF switch, and is also used to control one of the second input ends of the second RF switch to be connected to the output end of the second RF switch.

[0015] Compared with the prior art, the RF front-end module in the present invention designs a first matching circuit, a first-stage power amplifier circuit, a coupler, a first RF switch, an RF main 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 limits the hysteresis comparator 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 of the first RF switch or the second output end of the first RF switch, and control the first input end of the second RF switch 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 by the hysteresis comparator to attenuate the input power to the maximum input power of the power amplifier circuit, thereby avoiding damage to the power amplifier circuit, and there is no need to shut down or reduce the bias voltage of the subsequent stage, thereby ensuring the normal output of the RF signal, and at the same time, the subsequent output signal will not be distorted due to the reduction of the bias voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be described in detail below in conjunction with the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings. In the accompanying drawings: Figure 1 A circuit schematic diagram of a first RF front-end module provided by an embodiment of the present invention; Figure 2 A circuit schematic diagram of a first coupler in a first RF front-end module provided in an embodiment of the present invention; Figure 3 A circuit schematic diagram of a second coupler in a first RF front-end module provided in an embodiment of the present invention; Figure 4 A circuit schematic diagram of another attenuation path in the first RF front-end module provided in an embodiment of the present invention; Figure 5 A circuit schematic diagram of a second RF front-end module provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0018] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Embodiment 1 The embodiment of the present invention provides a radio frequency front-end module 100, Figures 1 to 4As shown, it includes a first matching circuit 1, a first-stage power amplifier circuit 2, a coupler 3, a first RF switch SW1, a 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.

[0021] The input end of the first matching circuit 1 is used to receive the radio frequency signal TXIn.

[0022] An input end of the first-stage power amplifier circuit 2 is connected to an output end of the first matching circuit 1 .

[0023] The input end of the coupler 3 is connected to the output end of the first-stage power amplifier circuit 2 .

[0024] The input end of the first RF switch SW1 is connected to the output end of the coupler 3 , the first output end of the first RF switch SW1 is connected to the first end of the RF main path 4 , and the second output end of the first RF switch SW1 is connected to the first end of the attenuation path 5 .

[0025] The attenuation path 5 is used to attenuate the power of the received radio frequency signal.

[0026] A first input end of the second RF switch SW2 is connected to a second end of the RF main path 4 , and a second input end of the second RF switch SW2 is connected to a second end of the attenuation path 5 .

[0027] An input end of the second matching circuit 6 is connected to an output end of the second RF switch SW2 .

[0028] An input end of the secondary power amplifier circuit 7 is connected to an output end of the second matching circuit 6 .

[0029] The input end of the third matching circuit 8 is connected to the output end of the secondary power amplifier circuit 7 , and the output end of the third matching circuit 8 is used to output the radio frequency signal TXOut.

[0030] 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 direct current voltage.

[0031] 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.

[0032] An input terminal of the first operational amplifier Amp1 is connected to an output terminal of the low-pass filter 10 .

[0033] A first input end of the hysteresis comparator 11 is connected to an output end of the first operational amplifier Amp1, a second input end of the hysteresis comparator 11 is used to access a reference signal, an output end of the 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, and the hysteresis comparator 11 is used to output a level signal according to a received voltage signal and a reference signal to control the input end of the first RF switch SW1 to be connected to a first output end of the first RF switch SW1 or a second output end of the first RF switch SW1, and to control the first input end of the second RF switch SW2 or the second input end of the second RF switch SW2 to be connected to an output end of the second RF switch SW2.

[0034] like Figure 2 As shown in FIG. 1 , as one design 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 .

[0035] 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 .

[0036] The first end of the second microstrip line 32 serves as a coupling end of the coupler 3 .

[0037] A first end of the first resistor R1 is connected to a second end of the second microstrip line 32 , and a second end of the first resistor R1 is grounded.

[0038] like Figure 3 As shown, as another design mode 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 RF switch SW1 serves as the output end of the coupler 3. Compared with the above-mentioned design mode of the coupler 3, this design mode of the coupler 3 has the advantages of simple circuit, small chip area and flexible adjustment.

[0039] In this embodiment, Figure 1 As 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.

[0040] 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.

[0041] 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.

[0042] In this embodiment, the attenuation path 5 includes a third resistor R3, a fourth resistor R4 and a fifth resistor R5.

[0043] like Figure 1 As shown in the figure, as one of the designs 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 can be understood as a π-type attenuator.

[0044] like Figure 4 As shown in FIG. 1 , as another design 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 can be understood as a T-type attenuator.

[0045] In this embodiment, Figure 1 As shown, the low pass filter 10 includes a sixth resistor R6 and a capacitor C.

[0046] A first end of the sixth resistor R6 serves as an input end of the low-pass filter 10 , and a second end of the sixth resistor R6 serves as an output end of the low-pass filter 10 .

[0047] A first end of the capacitor C is connected to a second end of the sixth resistor R6 , and a second end of the capacitor C is grounded.

[0048] In this embodiment, Figure 1 As shown, the hysteresis comparator 11 includes a seventh resistor R7, a second operational amplifier and an eighth resistor R8.

[0049] A first end of the seventh resistor R7 serves as a first input end of the hysteresis comparator 11 .

[0050] The non-inverting input terminal of the second operational amplifier is connected to the second end of the seventh resistor R7 , and the output terminal of the second operational amplifier serves as the output terminal of the hysteresis comparator 11 .

[0051] A first end of the eighth resistor R8 is connected to a second end of the seventh resistor R7 , and a second end of the eighth resistor R8 is connected to an output end of the second operational amplifier.

[0052] In this embodiment, the first operational amplifier Amp1 of the RF front-end module 100 is also called a low-frequency amplifier, which 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, and the reference signal connected to the second input terminal of the hysteresis comparator 11 is a voltage signal or a level signal, which can be provided by an internally designed low-dropout linear regulator (Low-dropout regulator, LDO) or provided in other ways.

[0053] 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. After the DC voltage is buffered and amplified by the first operational amplifier Amp1, the DC voltage output is Vdet2. The reference signal connected to the second input terminal of the hysteresis comparator 11 is Vref.

[0054] 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. Wherein, Vh and V1 are obtained by the following formulas respectively: ; ; It can be seen from this that the decision threshold, ie, whether the hysteresis comparator 11 outputs a high level signal or a low level signal, can be adjusted by modifying the reference voltage Vref.

[0055] Set the common end of the first single-pole double-throw switch to RF11, the first connection end of the first single-pole double-throw switch to RF12, the second connection end of the first single-pole double-throw switch to RF13, the common end of the second single-pole double-throw switch to RF21, the first connection end of the second single-pole double-throw switch to RF22, the second connection end of the second single-pole double-throw switch to RF33, and the level signal output by the hysteresis comparator 11 is CNT.

[0056] 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 to RF22 through RF12 and output to RF21.

[0057] 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 to the attenuation path 5 through RF13. The attenuation path 5 attenuates the RF signal to a certain degree of power, such as 20Db, and then outputs it to RF21 through RF23.

[0058] This is equivalent to when the RF front-end module 100 in this embodiment inputs a high-power signal, by switching to the attenuation path 5, the post-stage amplifier can be protected, and at the same time, the transmitted RF signal can continue to be transmitted without interruption.

[0059] 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, a 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, and 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 RF switch The first output end of the switch SW1 or the second output end of the first RF switch SW1, and the first input end of the second RF switch SW2 or the second input end of the second RF switch SW2 are connected to the output end of the second RF switch SW2, so that when the input power is large, the attenuation path 5 can be selected by the hysteresis comparator 11 to attenuate the input power to the maximum input power of the power amplifier circuit, thereby avoiding damage to the power amplifier circuit, and there is no need to shut down or reduce the subsequent stage bias voltage, thereby 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.

[0060] Embodiment 2 The RF front-end module 200 in this embodiment is different from the RF front-end module 100 in the above-mentioned embodiment 1 in that 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 in the RF front-end module 200 in this embodiment respectively include multiple and the same number, and the multiple attenuation paths 5 have different amounts of power attenuation.

[0061] 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, and is used to control 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 to control 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.

[0062] Compared with the design of the first embodiment, this design can make power control more flexible.

[0063] like Figure 5 As shown, in 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 respectively include two.

[0064] It is equivalent to that the attenuation path 5 includes two attenuation paths, namely a first attenuation path 51 and a second attenuation path 52 ; the hysteresis comparator 11 includes two hysteresis comparators, namely a first hysteresis comparator 111 and a second hysteresis comparator 112 .

[0065] 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.

[0066] The common end of the first single-pole three-throw switch serves as the input end of the first radio frequency switch SW1, the first connection end of the first single-pole three-throw switch serves as the first output end of the first radio frequency switch SW1, the second connection end of the first single-pole three-throw switch serves as one of the second output ends of the first radio frequency switch SW1, the third connection end of the first single-pole three-throw switch serves as another second output end of the first radio frequency switch SW1, the first control end of the first single-pole three-throw switch serves as one of the control ends of the first radio frequency switch SW1, and the second control end of the first single-pole three-throw switch serves as another control end of the first radio frequency switch SW1.

[0067] The first connection end of the second single-pole three-throw switch serves as the first input end of the second radio frequency switch SW2, the second connection end of the second single-pole three-throw switch serves as one of the second input ends of the second radio frequency switch SW2, the third connection end of the second single-pole three-throw switch serves as another second input end of the second radio frequency switch SW2, the common end of the second single-pole three-throw switch serves as the output end of the second radio frequency switch SW2, the first control end of the second single-pole three-throw switch serves as one of the control ends of the second radio frequency switch SW2, and the second control end of the second single-pole three-throw switch serves as another control end of the second radio frequency switch SW2.

[0068] Set the common end of the first single-pole three-throw switch to RF31, the first connection end of the first single-pole three-throw switch to RF32, the second connection end of the first single-pole three-throw switch to RF33, the third connection end of the first single-pole three-throw switch to RF34, the common end of the second single-pole three-throw switch to RF41, the first connection end of the second single-pole three-throw switch to RF42, the second connection end of the second single-pole three-throw switch to RF43, the third connection end of the second single-pole three-throw switch to RF44, the level signal output by the first hysteresis comparator 11 is CNT1, and the connected reference signal is Vref1, the level signal output by the second hysteresis comparator 11 is CNT2, and the connected reference signal is Vref2, and Vref1 is less than Vref2, the attenuation of the first attenuation path 5 is Att1, the attenuation of the second attenuation path 5 is Att2, and Att1 is less than Att2.

[0069] The control logic truth table of the first single-pole three-throw switch and the second single-pole three-throw switch is as follows:

[0070] When a low-power signal is input, both CNT1 and CNT2 output low-level signals, RF31 is connected to RF32, and then connected to RF42 and transmitted to RF41, and then amplified by the secondary power amplifier circuit 7 and output.

[0071] When a medium power signal is input, CNT1 outputs a high level signal and CNT2 outputs a low level signal. RF31 is connected to RF33, and then after power attenuation through the first attenuation path 5, it is connected to RF43 and transmitted to RF41, and then amplified by the secondary power amplifier circuit 7 and output.

[0072] When a high-power signal is input, both CNT1 and CNT2 output high-level signals, RF31 is connected to RF34, and then after power attenuation through the second attenuation path 5, it is connected to RF44 and transmitted to RF41, and then amplified by the secondary power amplifier circuit 7 and output.

[0073] Since the principle of the RF front-end module 200 of this embodiment is the same as or similar to the principle of the RF front-end module 100 in the above-mentioned embodiment 1, the RF front-end module 200 of this embodiment can also achieve the technical effect achieved by the RF front-end module 100 in the above-mentioned embodiment 1, which will not be repeated here.

[0074] It should be noted that the various embodiments described above with reference to the accompanying drawings are only used to illustrate the present invention rather than to limit the scope of the present invention. Those skilled in the art should understand that any modification or equivalent substitution of the present invention without departing from the spirit and scope of the present invention should be included within the scope of the present invention. In addition, unless otherwise indicated by the context, words appearing in the singular include the plural form, and vice versa. In addition, unless otherwise specified, all or part of any embodiment may 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-level power amplifier circuit, a coupler, a first RF switch, a RF main path, an attenuation path, a second RF switch, a second matching circuit, a second-level 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 a radio frequency signal; 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 RF main 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 radio frequency signal; 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; An input end of the second matching circuit is connected to an output end of the second RF switch; The input end of the secondary 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 secondary power amplifier circuit, and the output end of the third matching circuit is used to output a radio frequency signal; The input end of the power detection circuit is connected to the coupling end of the coupler, and is used to convert the received radio frequency signal into a direct current voltage; 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 radio frequency signal component and baseband envelope signal; The input terminal of the first operational amplifier is connected to the output terminal 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 the 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, and 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 of the first RF switch or the second output end of the first RF switch, and control the first input end of the second RF switch 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, characterized in that: 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 a coupling end of the coupler; A first end of the first resistor is connected to a second end of the second microstrip line, and a second end of the first resistor is grounded.

3. The RF front-end module according to claim 1, characterized in that: 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 radio frequency switch serves as the output end of the coupler.

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

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; 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.

7. The RF front-end module according to claim 1, characterized in that: The low-pass filter includes a sixth resistor and a capacitor; 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; 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.

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

9. The RF front-end module according to claim 1, characterized in that: 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 respectively include a plurality of the same number, and the attenuation amounts of the plurality of attenuation paths for power are different; The second output end of each of the first RF switches is connected to the first end of the attenuation path; the second input end of each of the first RF switches is connected to the second end of the attenuation path; the output end of each of the hysteresis comparators is respectively connected to a control end of the first RF switch and a control end of the second RF switch, and is used to control the input end of the first RF switch to be connected to one of the second output ends of the first RF switch, and is also used to control one of the second input ends of the second RF switch to be connected to the output end of the second RF switch.

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