Analog front-end circuit and transceiver

Abstract

The invention discloses an analog front-end circuit and a transceiver, which are applied to the technical field of signal processing and are used for solving the problems that the power consumption of the analog front-end circuit is relatively high and the linearity of a receiving circuit is reduced in the prior art. Specifically, a signal sending module performs digital-to-analog conversion and amplitude adjustment on an original sending signal output by a sending circuit to obtain a target sending signal in a voltage form, outputs the target sending signal to an external device through a receiving and sending port, copies the target sending signal according to a preset proportion through a signal copying module to obtain a synchronous voltage signal, and sends the synchronous voltage signal to an external device. And performing voltage-current conversion on the synchronous voltage signal to obtain a synchronous current signal, and offsetting the target sending signal in the mixed signal based on the synchronous current signal to obtain a target receiving signal. Therefore, the target sending signal is transmitted in a voltage form, and the power consumption is reduced; before the signal enters the receiving circuit, the target receiving signal is separated from the mixed signal, and the linearity of the receiving circuit is improved.

Description

Technical Field

[0001] The present application relates to the field of signal processing technology, and in particular to an analog front-end circuit and a transceiver. Background Art

[0002] SBD (Simultaneous Bidirectional) transceiver is a device that can send and receive data simultaneously on the same communication line. SBD transceivers can be set with different types of full-duplex interfaces, such as A-PHY (Automotive PHY), a high-speed, long-distance asymmetric serial interface for automotive applications. The full-duplex serial port feature of A-PHY, where the uplink and downlink signals are on the same line, requires the use of the analog front-end circuit in the A-PHY transceiver to effectively separate the target transmission signal from the target reception signal in the mixed signal.

[0003] At present, there are two ways to separate the target transmission signal from the target receiving signal in the analog front-end circuit. The first signal separation method is to generate a current signal opposite to the target transmission signal in the current form, and the opposite current signal and the mixed signal act on the same impedance, so that the target transmission signal in the mixed signal is offset, and the target receiving signal is obtained, and the signal separation is further realized. However, this method requires the generation and transmission of current signals, which often consumes a large amount of power. The second signal separation method is to generate a voltage signal opposite to the target transmission signal in the voltage form, and the opposite voltage signal and the mixed signal act on the input end of the receiving circuit respectively, so that the target transmission signal in the mixed signal is offset, and the target receiving signal is obtained, and the signal separation is further realized. However, in this method, the mixed signal and the opposite voltage signal act on the input end of the receiving circuit respectively, resulting in a large signal amplitude at the input end of the receiving circuit, which makes the linearity of the receiving circuit poor. Summary of the invention

[0004] The present application provides an analog front-end circuit and a transceiver, which are used to solve the problem in the prior art that the analog front-end circuit has high power consumption and reduces the linearity of the receiving circuit.

[0005] The technical solutions provided by this application are as follows: On the one hand, the present application provides an analog front-end circuit, including: a signal sending module, a signal copying module, a signal conversion module and a signal cancellation module; The input end of the signal sending module and the input end of the signal copying module are respectively connected to the sending circuit of the transceiver, and the output end of the signal sending module and the first input end of the signal cancellation module are connected to the transceiver port of the transceiver; the output end of the signal copying module is connected to the input end of the signal conversion module, the output end of the signal conversion module is connected to the second input end of the signal cancellation module, and the output end of the signal cancellation module is connected to the receiving circuit of the transceiver; The signal transmission module is used to perform digital-to-analog conversion and amplitude adjustment on the original transmission signal output by the transmission circuit to obtain a target transmission signal in the form of voltage; and output the target transmission signal to an external device through a transceiver port; The signal replication module is used to replicate the target transmission signal according to a preset ratio to obtain a synchronous voltage signal; The signal conversion module is used to perform voltage-current conversion on the synchronous voltage signal to obtain a synchronous current signal; The signal cancellation module is used to collect the mixed signal of the transceiver port, wherein the mixed signal includes a target transmission signal and a target reception signal; receive the synchronous current signal, cancel the target transmission signal in the mixed signal based on the synchronous current signal, and obtain the target reception signal.

[0006] Optionally, the signal sending module includes: a main driving module, a first resistor and a second resistor; The first input end of the main driving module is connected to the forward output end of the sending circuit, and the second input end of the main driving module is connected to the reverse output end of the sending circuit; the first output end of the main driving module is connected to the first end of the transceiver port via a first resistor; the second output end of the main driving module is connected to the second end of the transceiver port via a second resistor.

[0007] Optionally, the signal replication module includes: a secondary driving module, a third resistor, a fourth resistor and a fifth resistor; The first input end of the auxiliary driving module is connected to the forward output end of the transmitting circuit, and the second input end of the auxiliary driving module is connected to the reverse output end of the transmitting circuit; the first output end of the auxiliary driving module is connected to the first end of the fifth resistor and the first input end of the signal conversion module via the third resistor; the second output end of the auxiliary driving module is connected to the second end of the fifth resistor and the second input end of the signal conversion module via the fourth resistor.

[0008] Optionally, the fifth resistor is an adjustable resistor.

[0009] Optionally, the signal conversion module includes: a voltage extraction module, an impedance matching module and a current output module; The voltage extraction module, the impedance matching module and the current output module are connected in sequence, the input end of the voltage extraction module is connected to the output end of the signal replication module, and the output end of the current output module is connected to the second input end of the signal cancellation module; The voltage extraction module is used to track and collect the synchronous voltage signal to obtain the target voltage signal; The impedance matching module is used to perform impedance matching with the signal cancellation module to convert the target voltage signal into a synchronous current signal; The current output module is used to output synchronous current signals.

[0010] Optionally, the module includes a first impedance module and a second impedance module; the current output module includes a first field effect transistor, a second field effect transistor, a third field effect transistor, a fourth field effect transistor and a first power supply; The positive input terminal of the first operational amplifier is connected to the first output terminal of the signal replication module, and the reverse input terminal of the first operational amplifier and the output terminal of the first operational amplifier are both connected to the ground via the first impedance module; the source of the first field effect transistor and the second field effect transistor are respectively connected to the first power supply, and the gate of the first field effect transistor is respectively connected to the source of the second field effect transistor and the output terminal of the first operational amplifier; the drain of the first field effect transistor is connected to the output terminal of the first operational amplifier; and the drain of the second field effect transistor is connected to the second input terminal of the signal cancellation module; The positive input terminal of the second operational amplifier is connected to the second output terminal of the signal replication module, and the reverse input terminal of the second operational amplifier and the output terminal of the second operational amplifier are connected to the ground via the second impedance module; the sources of the third field effect transistor and the fourth field effect transistor are respectively connected to the first power supply, and the gate of the third field effect transistor is respectively connected to the source of the fourth field effect transistor and the output terminal of the second operational amplifier; the drain of the third field effect transistor is connected to the output terminal of the second operational amplifier; and the drain of the fourth field effect transistor is connected to the second input terminal of the signal cancellation module.

[0011] Optionally, the signal cancellation module includes: a first current source, a second current source, a third impedance module, a fourth impedance module and a second power supply; The input end of the first current source and the input end of the second current source are respectively connected to the second power supply, and the output end of the first current source is respectively connected to the first end of the third impedance module and the first output end of the signal conversion module; the first end of the third impedance module is also connected to the first input end of the receiving circuit; the second end of the third impedance module is connected to the second end of the transceiver port; The output end of the second current source is respectively connected to the first end of the fourth impedance module and the second output end of the signal conversion module; the first end of the fourth impedance module is also connected to the second input end of the receiving circuit; the second end of the fourth impedance module is connected to the first end of the transceiver port.

[0012] Optionally, the third impedance module includes at least one of a resistor, a capacitor and an inductor; the fourth impedance module includes at least one of a resistor, a capacitor and an inductor; and the total impedance of the third impedance module is the same as the total impedance of the third impedance module.

[0013] Optionally, the signal cancellation module further includes: a fifth field effect transistor and a sixth field effect transistor; The gate of the fifth field effect tube is connected to the gate of the sixth field effect tube, the source of the fifth field effect tube is respectively connected to the output end of the first current source and the first output end of the signal conversion module, and the drain of the fifth field effect tube is respectively connected to the first end of the third impedance module and the second end of the transceiver port; The source of the fifth field effect tube is respectively connected to the output end of the second current source and the second output end of the signal conversion module, and the drain of the fifth field effect tube is respectively connected to the first end of the fourth impedance module and the first end of the transceiver port.

[0014] On the other hand, the present application provides a transceiver, including: a transceiver port, a transmitting circuit, a receiving circuit and the above-mentioned analog front-end circuit; The analog front-end circuit is respectively connected with the transceiver port, the transmitting circuit and the receiving circuit.

[0015] The beneficial effects of this application are as follows: The present application uses a signal transmission module to perform digital-to-analog conversion and amplitude adjustment on the original transmission signal output by the transmission circuit to obtain a target transmission signal in voltage form, and outputs the target transmission signal to an external device through a transceiver port, that is, the target transmission signal is transmitted in voltage form, reducing the power consumption of the transmission and transmission of the target transmission signal; the present application also uses a signal replication module to copy the target transmission signal according to a preset ratio to obtain a synchronous voltage signal, and then uses a signal conversion module to perform voltage-current conversion on the synchronous voltage signal to obtain a synchronous current signal, and a signal cancellation module cancels the target transmission signal in the mixed signal based on the synchronous current signal to obtain a target receiving signal. Before the signal enters the receiving circuit, the target receiving signal is separated from the mixed signal to avoid processing a high-amplitude mixed signal at the input end of the receiving circuit, thereby improving the linearity of the receiving circuit.

[0016] Other features and advantages of the present application will be described in the subsequent description, and in part, will become apparent from the description, or will be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 This is a schematic diagram of a first circuit structure of an analog front-end circuit in an embodiment of the present application; Figure 2This is a schematic diagram of a second circuit structure of the analog front-end circuit in an embodiment of the present application; Figure 3 This is a schematic diagram of a third circuit structure of the analog front-end circuit in an embodiment of the present application; Figure 4 This is a fourth circuit structure diagram of the analog front-end circuit in the embodiment of the present application; Figure 5 Schematic diagram of the structure of the transceiver in the embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and beneficial effects of this application clearer, the technical solution in the embodiment of this application will be clearly and completely described below in conjunction with the drawings in the embodiment of this application. Obviously, the described embodiment is only a part of the embodiment of this application, not all the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0019] First, the application scenarios and design concepts of the embodiments of the present application are briefly introduced.

[0020] At present, SBD (Simultaneous Bidirectional) transceivers, i.e., simultaneous bidirectional transceivers, are devices that can send and receive data simultaneously on the same communication line. SBD transceivers are widely used in situations where high-speed and efficient data transmission is required, such as computer networks, communication networks, industrial automation and other fields. SBD transceivers can be set with different types of full-duplex interfaces, such as A-PHY (Automotive PHY), a high-speed, long-distance asymmetric serial interface for automotive applications, released by the MIPI (Mobile Industry Processor Interface) Alliance and incorporated into the IEEE standard. A-PHY meets the needs of asymmetric, high-throughput data communication between sensors (such as cameras, lidars, radars, etc.) and display devices and the system CPU through high-speed links. It provides a main unidirectional data flow, a bidirectional low-throughput control command and control data flow, and can also choose to directly provide the required power to peripheral devices (i.e., sensors and / or displays at the edge of the network) through the A-PHY data line. The full-duplex serial port feature of A-PHY's uplink and downlink signals are on the same line, so it is necessary to use the analog front-end circuit in the A-PHY transceiver to effectively separate the target transmission signal from the target reception signal in the mixed signal. The analog front-end circuit can separate the target transmission signal from the target reception signal in the following two ways. The first signal separation method is to generate a current signal opposite to the target transmission signal in the form of current, and the opposite current signal and the mixed signal act on the same impedance, so that the target transmission signal in the mixed signal is offset, and the target reception signal is obtained, and the signal separation is further realized. However, this method requires the generation and transmission of current signals, which often consumes a large amount of power. The second signal separation method is to generate a voltage signal opposite to the target transmission signal in the form of voltage, and the opposite voltage signal and the mixed signal act on the input end of the receiving circuit respectively, so that the target transmission signal in the mixed signal is offset, and the target reception signal is obtained, and the signal separation is further realized. However, in this method, the mixed signal and the opposite voltage signal act on the input end of the receiving circuit respectively, resulting in a large signal amplitude at the input end of the receiving circuit, which makes the linearity of the receiving circuit poor.

[0021] To this end, the present application performs digital-to-analog conversion and amplitude adjustment on the original transmission signal output by the transmission circuit through a signal transmission module to obtain a target transmission signal in voltage form, and outputs the target transmission signal to an external device through a transceiver port, that is, the target transmission signal is transmitted in voltage form, reducing the transmission and power consumption of the target transmission signal; the present application also performs voltage-current conversion on the synchronous voltage signal through a signal conversion module after copying the target transmission signal according to a preset ratio to obtain a synchronous voltage signal, and the signal cancellation module cancels the target transmission signal in the mixed signal based on the synchronous current signal to obtain a target receiving signal. Before the signal enters the receiving circuit, the target receiving signal is separated from the mixed signal to avoid processing a high-amplitude mixed signal at the input end of the receiving circuit, thereby improving the linearity of the receiving circuit.

[0022] After introducing the application scenarios and design concepts of the embodiments of the present application, the technical solutions provided by the embodiments of the present application are described in detail below.

[0023] The present application embodiment provides an analog front-end circuit, referring to Figure 1 As shown, the analog front-end circuit 100 provided in the embodiment of the present application at least includes: a signal sending module 110, a signal copying module 120, a signal conversion module 130 and a signal cancellation module 140; The input end of the signal sending module 110 and the input end of the signal copying module 120 are respectively connected to the sending circuit of the transceiver, and the output end of the signal sending module 110 and the first input end of the signal cancellation module 140 are connected to the transceiver port of the transceiver; the output end of the signal copying module 120 is connected to the input end of the signal conversion module 130, the output end of the signal conversion module 130 is connected to the second input end of the signal cancellation module 140, and the output end of the signal cancellation module 140 is connected to the receiving circuit of the transceiver; The signal transmission module 110 is used to perform digital-to-analog conversion and amplitude adjustment on the original transmission signal output by the transmission circuit to obtain a target transmission signal in the form of a voltage; and output the target transmission signal to an external device through a transceiver port; The signal replication module 120 is used to replicate the target transmission signal according to a preset ratio to obtain a synchronous voltage signal; The signal conversion module 130 is used to perform voltage-current conversion on the synchronous voltage signal to obtain a synchronous current signal; The signal cancellation module 140 is used to collect the mixed signal of the transceiver port, wherein the mixed signal includes a target transmission signal and a target reception signal; receive the synchronous current signal, cancel the target transmission signal in the mixed signal based on the synchronous current signal, and obtain the target reception signal.

[0024] exist Figure 1In the analog front-end circuit shown, the transceiver's transceiver port is a single-line full-duplex port for receiving and sending signals. The mixed signal of the transceiver port includes a target transmission signal and a target reception signal. The target transmission signal is a signal that needs to be sent to the external first device, and the target reception signal is a signal received from the external second device. The external first device and the external second device can be the same device or different devices. The original transmission signal output by the transmission circuit of the transceiver is a digital signal generated by the transmission circuit. The signal transmission module 110 performs digital-to-analog conversion on the digital signal to obtain an analog signal in the form of voltage. In order to maintain the accuracy and stability of the signal and adapt to other modules in the analog front-end circuit and the external first device, the amplitude of the analog signal in the form of voltage can be reduced or amplified as a whole to obtain the target transmission signal in the form of voltage. The signal replication module 120 replicates the target transmission signal according to a preset ratio to obtain a synchronous voltage signal, wherein the size of the preset ratio can be determined according to actual needs, and the general selection range is 0.125~0.5. The signal conversion module 130 performs voltage-to-current conversion on the synchronous voltage signal to obtain a synchronous current signal, wherein the voltage-to-current conversion is a linear conversion according to a preset first conversion ratio. After receiving the synchronous current signal, the signal cancellation module 140 performs current-to-voltage conversion on the synchronous current signal, and the synchronous current signal is linearly converted according to a preset second conversion ratio to obtain a synchronous cancellation signal in voltage form; wherein the synchronous cancellation signal in voltage form is equal in magnitude to the target transmission signal in the mixed signal and opposite in direction. The signal cancellation module 140 combines the synchronous cancellation signal in voltage form with the mixed signal to cancel the target transmission signal in the mixed signal and accurately separate the target received signal.

[0025] In specific implementation, the signal sending module in the analog front-end circuit has a variety of structures to achieve its function, see Figure 2 As shown, the signal sending module may include: a main driving module MD1, a first resistor R1 and a second resistor R2; The first input end of the main driving module MD1 is connected to the forward output end of the transmitting circuit, and the second input end of the main driving module MD1 is connected to the reverse output end of the transmitting circuit; the first output end of the main driving module MD1 is connected to the first end of the transceiver port via the first resistor R1; the second output end of the main driving module MD1 is connected to the second end of the transceiver port via the second resistor R2.

[0026] exist Figure 2In the analog front-end circuit shown, the resistance values ​​of the first resistor R1 and the second resistor R2 are equal. The original transmission signal is a differential signal, including a forward original transmission signal DIN and a reverse original transmission signal DIN-B. The transmission circuit inputs the forward original transmission signal DIN to the first input end of the main driving module through the forward output end, and the transmission circuit inputs the reverse original transmission signal DIN-B to the second input end of the main driving module MD1 through the reverse output end. The main driving module MD1 is used to perform digital-to-analog conversion on the forward original transmission signal and the reverse original transmission signal respectively. The main driving module and the first resistor R1 adjust the amplitude of the forward original transmission signal DIN to obtain the forward target transmission signal VTXP. The main driving module MD1 and the second resistor R2 adjust the amplitude of the reverse original transmission signal DIN-B to obtain the reverse target transmission signal VTXN.

[0027] In specific implementation, the signal replication module in the analog front-end circuit has a variety of structures to achieve its function, see Figure 2 As shown, the signal replication module may include: a secondary driving module CD1, a third resistor R3, a fourth resistor R4 and a fifth resistor R5; The first input end of the auxiliary driving module CD1 is connected to the forward output end of the transmitting circuit, and the second input end of the auxiliary driving module CD1 is connected to the reverse output end of the transmitting circuit; the first output end of the auxiliary driving module CD1 is connected to the first end of the fifth resistor R5 and the first input end of the signal conversion module via the third resistor R3; the second output end of the auxiliary driving module CD1 is connected to the second end of the fifth resistor R5 and the second input end of the signal conversion module via the fourth resistor R4.

[0028] exist Figure 2In the analog front-end circuit shown, the structure of the signal copy module is the same as that of the signal transmission module, and the structure of the auxiliary driving module CD1 is the same as that of the main driving module MD1, but the current output capacity of the main driving module MD1 is 2 to 8 times that of the auxiliary driving module CD1. The resistance values ​​of the third resistor R3 and the fourth resistor R4 are equal, and the resistance value of the third resistor R3 is greater than the resistance value of the first resistor R1, and is proportional to the resistance value of the first resistor R1. By inputting the forward original transmission DIN signal and the reverse original transmission signal DIN-B into the auxiliary driving module CD1, and through the third resistor R3, the fourth resistor R4 and the fifth resistor R5, it is possible to copy the target transmission signal according to a preset ratio to obtain a synchronous voltage signal, wherein the size of the preset ratio is determined according to the ratio of the current output capacity of the main driving module MD1 to the auxiliary driving module CD1, the ratio of the resistance values ​​of the first resistor R1 to the third resistor R3, and the size of the fifth resistor R5. The synchronous voltage signal includes a forward synchronous voltage signal VREPP and a reverse synchronous voltage signal VREPN. The forward synchronous voltage signal VREPP is obtained by copying the forward target sending VRXP signal according to a preset ratio, and the reverse synchronous voltage signal VREPN is obtained by copying the reverse target sending signal VRXN according to a preset ratio.

[0029] In a possible implementation manner, the fifth resistor R5 is an adjustable resistor and is used to adjust the voltage difference between the forward synchronous voltage signal VREPP and the reverse synchronous voltage signal VREPN.

[0030] In specific implementation, the signal conversion module in the analog front-end circuit has a variety of structures to achieve its function, see Figure 3 As shown, the signal conversion module 130 may include: a voltage extraction module 131, an impedance matching module 132 and a current output module 133; The voltage extraction module 131, the impedance matching module 132 and the current output module 133 are connected in sequence, the input end of the voltage extraction module 131 is connected to the output end of the signal replication module 120, and the output end of the current output module 133 is connected to the second input end of the signal cancellation module 140; The voltage extraction module 131 is used to track and collect the synchronous voltage signal to obtain the target voltage signal; The impedance matching module 132 is used to perform impedance matching with the signal cancellation module to convert the target voltage signal into a synchronous current signal; The current output module 133 is used to output a synchronous current signal.

[0031] exist Figure 3In the analog front-end circuit shown, the voltage extraction module 131 can generate a target voltage signal obtained by tracking the synchronous voltage signal in a synchronous closed-loop or open-loop manner. The purpose of collecting the synchronous voltage signal by tracking rather than directly acquiring the synchronous voltage signal is to avoid drawing current from the generating end of the synchronous voltage signal, increasing the load and driving difficulty or speed of the signal replication module 120. The impedance matching module 132 converts the target voltage signal into a synchronous current signal by setting an impedance proportional to and of the same type as the signal cancellation module 140, and by using an impedance proportional to and of the same type as the signal cancellation module 140, so that the current output module 133 outputs the synchronous current signal to the signal cancellation module.

[0032] For details, see Figure 4 As shown, the voltage extraction module includes a first operational amplifier OTA1 and a second operational amplifier OTA2; the impedance matching module includes a first impedance module Z1 and a second impedance module Z2; the current output module includes a first field effect transistor M1, a second field effect transistor M2, a third field effect transistor M3, a fourth field effect transistor M4 and a first power supply; The positive input terminal of the first operational amplifier OTA1 is connected to the first output terminal of the signal replication module, and the reverse input terminal of the first operational amplifier OTA1 and the output terminal of the first operational amplifier are connected to the ground via the first impedance module Z1; the source of the first field effect transistor M1 and the second field effect transistor M2 are respectively connected to the first power supply, and the gate of the first field effect transistor M1 is respectively connected to the source of the second field effect transistor M2 and the output terminal of the first operational amplifier OTA1; the drain of the first field effect transistor M1 is connected to the output terminal of the first operational amplifier OTA1; the drain of the second field effect transistor M2 is connected to the second input terminal of the signal cancellation module; The positive input terminal of the second operational amplifier OTA2 is connected to the second output terminal of the signal replication module, and the reverse input terminal of the second operational amplifier OTA2 and the output terminal of the second operational amplifier OTA2 are both connected to the ground via the second impedance module Z2; the sources of the third field effect transistor M3 and the fourth field effect transistor M4 are respectively connected to the first power supply, and the gate of the third field effect transistor M3 is respectively connected to the source of the fourth field effect transistor M4 and the output terminal of the second operational amplifier OTA2; the drain of the third field effect transistor M3 is connected to the output terminal of the second operational amplifier OTA2; the drain of the fourth field effect transistor M4 is connected to the second input terminal of the signal cancellation module.

[0033] exist Figure 4In the analog front-end circuit shown, the first operational amplifier OTA1 generates a forward target voltage signal VG1 through a synchronous closed loop. Specifically, the gain of the first operational amplifier OTA2 is set to a high gain so that the voltage signals at the positive input and output of the first operational amplifier are the same. The input of the first operational amplifier is the forward synchronous voltage signal VREPP, and the output of the first operational amplifier is the forward target voltage signal VG1 obtained by tracking the forward synchronous voltage signal VREPP. The forward target voltage signal VG1 flows through the first impedance module Z1 to generate a forward synchronous current signal I BIAS1 The first field effect tube M1 and the second field effect tube M2 form a current mirror, and the forward synchronous current signal I BIAS1 The output is sent to the signal cancellation module through the current mirror. Correspondingly, the second operational amplifier OTA2 generates a reverse target voltage signal VG2 through a synchronous closed loop. Specifically, the gain of the second operational amplifier OTA2 is set to a high gain so that the voltage signals at the positive input and output of the second operational amplifier OTA2 are the same. The input of the second operational amplifier OTA2 is the reverse synchronous voltage signal VREPN, and the output of the second operational amplifier OTA2 is the reverse target voltage signal VG2 obtained by tracking the reverse synchronous voltage signal VREPN. The reverse target voltage signal VG2 flows through the second impedance module Z2 to generate a reverse synchronous current signal I BIAS2 The third field effect tube M3 and the fourth field effect tube M4 form a current mirror, and the reverse synchronous current signal I BIAS2 The first impedance module Z1 and the second impedance module Z2 have the same internal structure, and both the first impedance module Z1 and the second impedance module Z2 are provided with at least one of a resistor, a capacitor and an inductor; the total impedance of the first impedance module Z1 is the same as the total impedance of the second impedance module Z2.

[0034] In specific implementation, the signal cancellation module in the analog front-end circuit has a variety of structures to achieve its function, see Figure 4 As shown, the signal cancellation module may include: a first current source I1, a second current source I2, a third impedance module Z3, a fourth impedance module Z4 and a second power supply; The input end of the first current source I1 and the input end of the second current source I2 are respectively connected to the second power supply, and the output end of the first current source I1 is respectively connected to the first end of the third impedance module Z3 and the first output end of the signal conversion module; the first end of the third impedance module Z3 is also connected to the first input end of the receiving circuit; the second end of the third impedance module Z3 is connected to the second end of the transceiver port; The output end of the second current source I2 is respectively connected to the first end of the fourth impedance module Z4 and the second output end of the signal conversion module; the first end of the fourth impedance module Z4 is also connected to the second input end of the receiving circuit; the second end of the fourth impedance module Z4 is connected to the first end of the transceiver port.

[0035] In a possible implementation, the third impedance module includes at least one of a resistor, a capacitor, and an inductor; the fourth impedance module includes at least one of a resistor, a capacitor, and an inductor; the total impedance of the third impedance module is the same as the total impedance of the fourth impedance module. The first impedance module and the third impedance module have the same impedance type, and the total impedances are proportional. The second impedance module and the fourth impedance module have the same impedance type, and the total impedances are proportional.

[0036] In one possible implementation, see Figure 4 As shown, the signal cancellation module further includes: a fifth field effect transistor M5 and a sixth field effect transistor M6; The gate of the fifth field effect transistor M5 is connected to the gate of the sixth field effect transistor M6, the source of the fifth field effect transistor M5 is respectively connected to the output end of the first current source I1 and the first output end of the signal conversion module, and the drain of the fifth field effect transistor M5 is respectively connected to the first end of the third impedance module Z3 and the second end of the transceiver port; The source of the sixth field effect transistor M6 is respectively connected to the output end of the second current source I2 and the second output end of the signal conversion module, and the drain of the sixth field effect transistor M6 is respectively connected to the first end of the fourth impedance module Z4 and the first end of the transceiver port.

[0037] exist Figure 4 In the analog front-end circuit shown, the fifth field effect transistor M5 is used to implement isolation between the first output end of the signal conversion module and the second end of the transceiver port, and to remove the restriction that the voltage of the first output end of the signal conversion module and the second end of the transceiver port are the same. The sixth field effect transistor M6 is used to implement isolation between the second output end of the signal conversion module and the first end of the transceiver port, and to remove the restriction that the voltage of the second output end of the signal conversion module and the first end of the transceiver port are the same.

[0038] Next, Figure 4 Taking the analog front-end circuit shown in the figure as an example, the principle of canceling the target transmitted signal in the mixed signal to obtain the target received signal is explained in detail.

[0039] Taking the output terminal RXP of the analog front-end circuit connected to the receiving circuit as an example, according to Kirchhoff's law, the voltage V at the output terminal RXP of the analog front-end circuit can be calculated. RXPO for: (1) Among them, V RXPOis the voltage value of the output terminal RXP of the analog front-end circuit, V TXP The voltage value of the signal sent to the target in the mixed signal; V RXP I is the voltage value of the target received signal in the mixed signal; REPN The signal conversion module converts the voltage V of the synchronous voltage signal REPN The current value of the synchronous current signal obtained after voltage-current conversion; Z HBY4 is the impedance value of the fourth impedance module Z4 in the signal cancellation module.

[0040] Current value I of the synchronous current signal REPN The signal conversion module converts the voltage V of the synchronous voltage signal REPN The current value I of the synchronous current signal obtained after voltage-current conversion REPN It is expressed by the following formula (2); (2) Among them, V REPN The signal copy module copies the voltage value V of the target sending signal according to the preset ratio TXN The voltage value of the synchronous voltage signal is obtained. HBY2 is the impedance value of the second impedance module Z2 in the voltage extraction module.

[0041] The voltage value of the synchronous voltage signal V REPN The voltage value V of the target transmission signal output by the signal transmission module TXN There is a proportional relationship between them, so we can get: (3) Wherein, a is the preset ratio of the signal replication module to replicate the target transmission signal.

[0042] Substituting the above formula (2) and formula (3) into formula (1), we can obtain: (4) Since the forward original transmission signal DIN and the reverse original transmission signal DIN-B are two completely opposite signals, correspondingly, the forward target transmission signal VTXP and the reverse target transmission signal VTXN obtained by digital-to-analog conversion and amplitude adjustment of the forward original transmission signal DIN and the reverse original transmission signal DIN-B are two completely opposite signals. Therefore, the voltage value V of the forward target transmission signal VTXP can be determined. TXP and the voltage value V of the reverse target transmission signal VTXN TXN The sum of is zero, that is, V TXP +V TXN =0. In formula (4), When the voltage at the output terminal RXP connecting the analog front-end circuit and the receiving circuit is , canceling the target transmission signal VTXP in the mixed signal to obtain the target reception signal VRXP. Similarly, for the output terminal RXN connected to the analog front-end circuit and the receiving circuit, the target transmission signal VTXN in the mixed signal can also be canceled to obtain the target reception signal VRXN.

[0043] Based on the above embodiments, the present application provides a transceiver. Figure 5 As shown, the transceiver 200 provided in the embodiment of the present application at least includes: a transceiver port 210, a transmitting circuit 220, a receiving circuit 230 and the analog front-end circuit 100 provided in the above embodiment; The analog front end circuit 100 is connected to the transceiver port 210 , the transmitting circuit 220 , and the receiving circuit 230 , respectively.

[0044] It should be noted that, although several units or subunits of the device are mentioned in the above detailed description, this division is merely exemplary and not mandatory. In fact, according to the embodiments of the present application, the features and functions of two or more units described above can be embodied in one unit. Conversely, the features and functions of one unit described above can be further divided into multiple units to be embodied.

[0045] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0046] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. An analog front-end circuit, characterized in that: include: Signal sending module, signal copying module, signal conversion module and signal cancellation module; The input end of the signal sending module and the input end of the signal copying module are respectively connected to the sending circuit of the transceiver, and the output end of the signal sending module and the first input end of the signal cancellation module are connected to the transceiver port of the transceiver; the output end of the signal copying module is connected to the input end of the signal conversion module, the output end of the signal conversion module is connected to the second input end of the signal cancellation module, and the output end of the signal cancellation module is connected to the receiving circuit of the transceiver; The signal transmission module is used to perform digital-to-analog conversion and amplitude adjustment on the original transmission signal output by the transmission circuit to obtain a target transmission signal in the form of a voltage; and output the target transmission signal to an external device through a transceiver port; The signal replication module is used to replicate the target transmission signal according to a preset ratio to obtain a synchronous voltage signal; The signal conversion module is used to perform voltage-current conversion on the synchronous voltage signal to obtain a synchronous current signal; The signal cancellation module is used to collect the mixed signal of the transceiver port, wherein the mixed signal includes a target transmission signal and a target reception signal; receive the synchronous current signal, and cancel the target transmission signal in the mixed signal based on the synchronous current signal to obtain a target reception signal.

2. The analog front-end circuit according to claim 1, characterized in that: The signal sending module includes: a main driving module, a first resistor and a second resistor; The first input end of the main driving module is connected to the forward output end of the sending circuit, and the second input end of the main driving module is connected to the reverse output end of the sending circuit; the first output end of the main driving module is connected to the first end of the transceiver port via a first resistor; the second output end of the main driving module is connected to the second end of the transceiver port via a second resistor.

3. The analog front-end circuit according to claim 1, characterized in that: The signal replication module includes: a secondary driving module, a third resistor, a fourth resistor and a fifth resistor; The first input end of the auxiliary driving module is connected to the forward output end of the transmitting circuit, and the second input end of the auxiliary driving module is connected to the reverse output end of the transmitting circuit; the first output end of the auxiliary driving module is connected to the first end of the fifth resistor and the first input end of the signal conversion module via a third resistor; the second output end of the auxiliary driving module is connected to the second end of the fifth resistor and the second input end of the signal conversion module via a fourth resistor.

4. The analog front-end circuit according to claim 3, characterized in that: The fifth resistor is an adjustable resistor.

5. The analog front-end circuit according to any one of claims 1 to 4, characterized in that: The signal conversion module includes: a voltage extraction module, an impedance matching module and a current output module; The voltage extraction module, the impedance matching module and the current output module are connected in sequence, the input end of the voltage extraction module is connected to the output end of the signal replication module, and the output end of the current output module is connected to the second input end of the signal cancellation module; The voltage extraction module is used to track and collect the synchronous voltage signal to obtain a target voltage signal; The impedance matching module is used to perform impedance matching with the signal cancellation module to convert the target voltage signal into a synchronous current signal; The current output module is used to output the synchronous current signal.

6. The analog front-end circuit according to claim 5, characterized in that: The voltage extraction module includes a first operational amplifier and a second operational amplifier; the impedance matching module includes a first impedance module and a second impedance module; the current output module includes a first field effect transistor, a second field effect transistor, a third field effect transistor, a fourth field effect transistor and a first power supply; The positive input terminal of the first operational amplifier is connected to the first output terminal of the signal replication module, and the reverse input terminal of the first operational amplifier and the output terminal of the first operational amplifier are both connected to the ground via the first impedance module; the source terminals of the first field effect transistor and the second field effect transistor are respectively connected to the first power supply, and the gate terminal of the first field effect transistor is respectively connected to the source terminal of the second field effect transistor and the output terminal of the first operational amplifier; the drain terminal of the first field effect transistor is connected to the output terminal of the first operational amplifier; and the drain terminal of the second field effect transistor is connected to the second input terminal of the signal cancellation module; The positive input terminal of the second operational amplifier is connected to the second output terminal of the signal replication module, and the reverse input terminal of the second operational amplifier and the output terminal of the second operational amplifier are both connected to the ground via the second impedance module; the sources of the third field effect transistor and the fourth field effect transistor are respectively connected to the first power supply, and the gate of the third field effect transistor is respectively connected to the source of the fourth field effect transistor and the output terminal of the second operational amplifier; the drain of the third field effect transistor is connected to the output terminal of the second operational amplifier; and the drain of the fourth field effect transistor is connected to the second input terminal of the signal cancellation module.

7. The analog front-end circuit according to claim 6, characterized in that: The signal cancellation module includes: a first current source, a second current source, a third impedance module, a fourth impedance module and a second power supply; The input end of the first current source and the input end of the second current source are respectively connected to the second power supply, and the output end of the first current source is respectively connected to the first end of the third impedance module and the first output end of the signal conversion module; the first end of the third impedance module is also connected to the first input end of the receiving circuit; the second end of the third impedance module is connected to the second end of the transceiver port; The output end of the second current source is respectively connected to the first end of the fourth impedance module and the second output end of the signal conversion module; the first end of the fourth impedance module is also connected to the second input end of the receiving circuit; the second end of the fourth impedance module is connected to the first end of the transceiver port.

8. The analog front-end circuit according to claim 7, characterized in that: The third impedance module includes at least one of a resistor, a capacitor and an inductor; the fourth impedance module includes at least one of a resistor, a capacitor and an inductor; and the total impedance of the third impedance module is the same as the total impedance of the fourth impedance module.

9. The analog front-end circuit according to claim 7, characterized in that: The signal cancellation module further includes: a fifth field effect transistor and a sixth field effect transistor; The gate of the fifth field effect transistor is connected to the gate of the sixth field effect transistor, the source of the fifth field effect transistor is respectively connected to the output end of the first current source and the first output end of the signal conversion module, and the drain of the fifth field effect transistor is respectively connected to the first end of the third impedance module and the second end of the transceiver port; The source of the fifth field effect transistor is respectively connected to the output end of the second current source and the second output end of the signal conversion module, and the drain of the fifth field effect transistor is respectively connected to the first end of the fourth impedance module and the first end of the transceiver port.

10. A transceiver, characterized in that: include: A transceiver port, a transmitting circuit, a receiving circuit, and an analog front-end circuit as claimed in any one of claims 1 to 9; The analog front-end circuit is connected to the transceiver port, the transmitting circuit and the receiving circuit respectively.

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