CN114095049B - Radio frequency receiving and transmitting switch circuit, radio frequency front-end circuit and radio frequency transceiver - Google Patents

Abstract

The application provides a radio frequency receiving and transmitting switch circuit, a radio frequency front-end circuit and a radio frequency transceiver, wherein the radio frequency receiving and transmitting switch circuit is characterized in that a first switch and a second switch for realizing radio frequency receiving and transmitting switching are respectively arranged between corresponding points and ground in a serial-parallel branch, the radio frequency receiving and transmitting switching can be realized through on-off control of the two switches, and a matching network required by the radio frequency front-end circuit is formed at the same time, so that the radio frequency receiving and transmitting switch circuit is high in universality and high in integration level; the two switches are not in the signal path, so that the problems of insertion loss and deterioration of the receiving and transmitting performance caused by adding the radio frequency receiving and transmitting switch in the signal path of the antenna can be avoided while the time-sharing high-performance work of the radio frequency receiving and transmitting is realized; in addition, the scheme can realize the higher harmonic suppression of the transmitting carrier wave by connecting a capacitor in parallel at the inductance of the transmitting matching unit.

Description

A radio frequency transceiver switch circuit, radio frequency front-end circuit and radio frequency transceiver

technical field

The invention relates to the field of communication electronic integrated circuits, in particular to a radio frequency transceiver switch circuit, a radio frequency front end circuit and a radio frequency transceiver.

Background technique

In a time-division wireless communication device, generally only one antenna is provided. The radio frequency front-end circuit in the device must include a radio frequency transceiver switch circuit for switching between the receiving path and the transmitting path.

As shown in Figure 1, the existing RF transceiver switching circuit mainly uses MOS tubes (M1, M2, M3, M4 in Figure 1) to form a single-pole double-throw switching circuit, which is controlled by the control signals Vc and Vc', so that the antenna The ANT port is respectively connected to the input port Rx of the receiving path or the output port Tx of the transmitting path. Since the radio frequency transceiver switch circuit is equipped with a radio frequency transceiver switch in the signal path of the antenna, it will cause insertion loss and deteriorate the transceiver performance.

Contents of the invention

In this regard, the application provides a radio frequency transceiver switch circuit, a radio frequency front-end circuit and a radio frequency transceiver to solve the problem of insertion loss and deterioration of transceiver performance caused by adding a radio frequency transceiver switch in the signal path of the antenna in the existing radio frequency transceiver switch circuit question.

In order to achieve the above purpose, embodiments of the present invention provide the following technical solutions:

The first aspect of the present application discloses a radio frequency transceiver switch circuit, including: a series-parallel branch, a first switch, and a second switch; wherein:

The series-parallel branches are respectively connected to the input port of the receiving path, the output port of the transmitting path, and the antenna;

The first switch and the second switch are respectively arranged between corresponding points in the series-parallel branch and ground;

When the first switch is opened and the second switch is closed, the output port of the transmitting path is shorted to ground; the connection between the input port of the receiving path and the antenna of the series-parallel branch is part, is the corresponding matching network;

When the first switch is closed and the second switch is opened, the input port of the receiving path is shorted to ground; the connection between the output port of the transmitting path and the antenna of the series-parallel branch is Part, at least including: a transmission matching unit, or N transmission matching units connected in series in sequence, where N is a positive integer greater than 1;

The emission matching unit includes: two capacitors and an inductance; the inductance is connected in parallel with one of the capacitors, and one end of the parallel connection is grounded through the other capacitor, and is used as the output end of the emission matching unit for connecting The input end of the antenna or the latter transmission matching unit; the other end of the parallel connection is used as the input end of the transmission matching unit, and is used to connect the output end of the previous transmission matching unit or the output port of the transmission path ;

The second switch is arranged between any point on the series branch of the N transmitting matching units and ground.

Optionally, in the above radio frequency transceiver switch circuit, when the first switch is open and the second switch is closed, the connection between the input port of the receiving path and the antenna of the series-parallel branch is The part is an equivalent form of a π-type matching network or an equivalent or simplified form of a T-type matching network;

When the first switch is closed and the second switch is opened, the part of the series-parallel branch between the output port of the transmission path and the antenna is a second-order LC impedance matching network or a second-order LC Equivalent or simplified form of an impedance matching network.

Optionally, in the above-mentioned radio frequency transceiver switch circuit, N=2, and the series-parallel branch includes: a first capacitor, a second capacitor, a first inductor, a third capacitor, a fourth capacitor, a second inductor, and a first capacitor. Three inductors;

One end of the first capacitor is respectively connected to one end of the first inductor and one end of the third capacitor, and the connection point is connected to the antenna;

The other end of the first capacitor is connected to one end of the second inductor, and the connection points are respectively connected to the first end of the first switch and the input port of the receiving path;

The other end of the second inductor and the other end of the first switch are grounded;

The other end of the first inductor is respectively connected to the other end of the third capacitor, one end of the third inductor, one end of the second capacitor, one end of the fourth capacitor and the second switch. connected to the first end;

The other end of the third inductor is respectively connected to the other end of the fourth capacitor and the output port of the transmission path;

The other end of the second capacitor and the second end of the second switch are both grounded.

Optionally, in the above-mentioned radio frequency transceiver switch circuit, N=1, and the series-parallel branch includes: a first capacitor, a second capacitor, a third capacitor, a first inductor, and a second inductor;

One end of the first capacitor is respectively connected to one end of the first inductor and one end of the third capacitor, and the connection point is connected to the antenna;

The other end of the first capacitor is connected to one end of the second inductor, and the connection points are respectively connected to the first end of the first switch and the input port of the receiving path;

The other end of the second inductor and the second end of the first switch are both grounded;

The other end of the first inductor is respectively connected to the other end of the third capacitor, one end of the second capacitor, the first end of the second switch, and the output port of the transmission path;

The other end of the second capacitor and the second end of the second switch are both grounded.

Optionally, in the above-mentioned radio frequency transceiver switch circuit, N=2, and the series-parallel branch includes: a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a an inductance, a second inductance and a third inductance;

One end of the first capacitor is respectively connected to one end of the second capacitor, one end of the second inductor and one end of the fifth capacitor, and the connection point is connected to the antenna;

The other end of the first capacitor is respectively connected to one end of the first inductor, the first end of the first switch, and one end of the third capacitor;

The other end of the third capacitor is connected to the input port of the receiving channel;

The other end of the first inductor and the second end of the first switch are both grounded;

The other end of the second inductor is respectively connected to the other end of the fifth capacitor, one end of the fourth capacitor, the first end of the second switch, one end of the sixth capacitor, and the third capacitor. One end of the inductor is connected;

The other end of the third inductor is respectively connected to the other end of the sixth capacitor and the output port of the transmission path;

The other end of the second capacitor, the other end of the fourth capacitor and the second end of the second switch are all grounded.

Optionally, in the above-mentioned radio frequency transceiver switch circuit, N=1, and the series-parallel branch includes: a first capacitor, a second capacitor, a fifth capacitor, a first inductor, and a second inductor;

One end of the first capacitor is respectively connected to one end of the second capacitor, one end of the fifth capacitor and one end of the second inductor, and the connection point is connected to the antenna;

The other end of the first capacitor is connected to one end of the first inductor, and the connection points are respectively connected to the first end of the first switch and the input port of the receiving path;

The other end of the first inductor and the second end of the first switch are both grounded;

The other end of the second inductor is respectively connected to the other end of the fifth capacitor, the first end of the second switch, and the output port of the transmission path;

The other end of the second capacitor and the second end of the second switch are both grounded.

Optionally, in the above radio frequency transceiver switch circuit, both the first switch and the second switch are electronic switches.

The second aspect of the present application discloses a radio frequency front-end circuit, including: a receiving path, a transmitting path, and any radio frequency transceiver switch circuit disclosed in the first aspect above.

The third aspect of the present application discloses a radio frequency transceiver, including: an antenna and at least one radio frequency front-end circuit as disclosed in the second aspect.

In the radio frequency transceiver switch circuit provided by the present invention, the first switch and the second switch for realizing radio frequency transceiver switching are respectively arranged between corresponding points in the series-parallel branch and the ground, and the radio frequency transceiver can be realized through the on-off control of the two switches switch, and at the same time constitute the matching network required by the RF front-end circuit, with strong versatility and high integration; and the two switches are not in the signal path, while realizing the time-sharing high-performance work of RF transceiver, it can also avoid The insertion loss caused by the addition of a radio frequency transceiver switch in the signal path of the antenna and the deterioration of the transceiver performance; in addition, this solution connects a capacitor in parallel to the inductance of the transmitting matching unit, which can also suppress the high-order harmonics of the transmitting carrier.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

Fig. 1 is the circuit structural representation of existing a kind of radio frequency transceiver switch circuit;

FIG. 2 is a schematic structural diagram of a radio frequency transceiver switch circuit provided by an embodiment of the present application;

Fig. 3a is a schematic structural diagram of a first switch provided in an embodiment of the present application;

Fig. 3b is a schematic structural diagram of a second switch provided by the embodiment of the present application;

Fig. 4 to Fig. 7 are the circuit structural diagrams of four kinds of radio frequency transceiver switch circuits provided by the embodiment of the present application;

FIG. 8 is a schematic structural diagram of a radio frequency front-end circuit provided by an embodiment of the present application;

FIG. 9 is a schematic structural diagram of a radio frequency transceiver provided by an embodiment of the present application.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The embodiment of the present application provides a radio frequency transceiver switch circuit to solve the problems of insertion loss and deterioration of transceiver performance caused by adding a radio frequency transceiver switch in the signal path of the antenna in the existing radio frequency transceiver switch circuit.

Please refer to FIG. 2 , the radio frequency transceiver switch circuit mainly includes: a series-parallel branch 101 , a first switch S1 and a second switch S2 .

Wherein, the series-parallel branch 101 is respectively connected to the input port Rx of the receiving path, the output port Tx of the transmitting path, and the antenna. Port ANT in FIG. 2 is a port connected to an antenna.

The first switch S1 and the second switch S2 are respectively arranged between corresponding points in the series-parallel branch 101 and ground. The specific implementation devices of the first switch S1 and the second switch S2 may be electronic switches, such as MOS transistors (as shown in FIG. 3a and FIG. 3b ), and of course other types of switch tubes may also be used. The present application does not limit the specific types of the first switch S1 and the second switch S2, and both belong to the protection scope of the present application.

Wherein, if the specific structure of the first switch S1 is as shown in Figure 3a, the drain Ts1 of the first switch S1 is the first end of the first switch S1, and the source of the first switch S1 is the second end of the first switch S1 , grounded, and the gate of the first switch S1 receives the control signal Vc through a resistor. If the specific structure of the second switch S2 is shown in Figure 3b, the drain Ts2 of the second switch S2 is the first end of the second switch S2, the source of the second switch S2 is the second end of the second switch S2, and is grounded. , the gate of the second switch S2 receives the control signal Vc' through a resistor.

In practical applications, the series-parallel branch 101 may also be composed of a receiving matching module and a transmitting matching module. Specifically, when both the first switch S1 and the second switch S2 are turned off, the part of the series-parallel branch 101 between the output port Tx of the transmission path and the antenna is a receiving matching module (as shown in the upper part of FIG. 2 ), and the part of the series-parallel branch 101 between the output port Tx of the transmission path and the antenna is a transmission matching module (not shown). When the first switch S1 is opened and the second switch S2 is closed, the output port TX of the transmission path is shorted to the ground by the second switch S2, and the part of the series-parallel branch 101 between the input port RX of the reception path and the antenna ANT , that is, the topology jointly formed by the transmitting matching module, the second switch S2 and the receiving matching module is a corresponding matching network. When the first switch S1 is closed and the second switch S2 is turned off, the output port TX of the transmission path is shorted to ground by the second switch S2, and the part of the series-parallel branch between the output port TX of the transmission path and the antenna ANT, That is, the topology jointly constituted by the receiving matching module, the first switch S1 and the transmitting matching module includes at least one transmitting matching unit 102 , or N transmitting matching units 102 sequentially connected in series, where N is a positive integer.

It should be noted that the specific value of N can be determined according to actual application conditions and user needs, and this application does not make specific limitations. No matter what value N takes, it belongs to the protection scope of this application.

In practical applications, as shown in FIG. 2 , the emission matching unit 102 includes: two capacitors and an inductor; the inductor is connected in parallel with one capacitor, and one end of the parallel connection is grounded through another capacitor, and serves as the output end of the emission matching unit 102 , used to connect the antenna or the input end of the next transmission matching unit 102; the other end of the parallel connection is used as the input end of the transmission matching unit 102, and is used to connect the output end of the previous transmission matching unit 102 or the output port TX of the transmission path. Two emission matching units 102 are shown in Fig. 2: in the former emission matching unit 102, the inductance Ln and the capacitance Cn' are connected in parallel between its input end and the output end, and its output end is grounded through the capacitance Cn; the latter emission matching unit In the unit 102, the inductor L1 and the capacitor C1' are connected in parallel between its input terminal and its output terminal, and its output terminal is grounded through the capacitor C1. Through the parallel connection of inductors and capacitors in the N transmitting matching units 102, N-order harmonic suppression can be realized, and harmonics output by the carrier can be suppressed.

The first switch S1 is set between any point in the receiving matching module and the ground; the second switch S2 is set between any point on the series branch of the N transmitting matching units 102 and the ground. At this time, if the first switch S1 is open and the second switch S2 is closed, the output port TX of the transmission path is directly shorted to the ground by the second switch S2, or, through the connection between the output port TX of the transmission path and the second switch S2 The transmission matching unit 102 between is shorted to the ground by the second switch S2; and the part between the input port RX of the receiving path and the antenna ANT of the series-parallel branch 101, that is, the transmission matching between the antenna ANT and the second switch S2 The topology jointly formed by the unit 102, the second switch S2 and the receiving matching module is a corresponding matching network. If the first switch S1 is closed and the second switch S2 is open, the input port RX of the receiving path is directly shorted to the ground by the first switch S1, or, the input port RX of the receiving path in the receiving matching module and the first switch S1 Part of the device in between is short-circuited to ground by the first switch S1; and the part of the series-parallel branch between the output port TX of the transmission path and the antenna ANT, that is, the receiving matching module is between the antenna ANT and the first switch S1 The topology composed of some devices, the first switch S1 and the emission matching module at least includes: one emission matching unit 102, or N emission matching units 102 connected in series in sequence, N is a positive integer, and Fig. 2 only uses two The transmission matching unit 102 is taken as an example.

It should be noted that, in practical applications, the series-parallel branch 101 includes at least two inductors and at least one capacitor. Simpler, take N as 1 or 2 as an example for illustration:

When the first switch S1 is open and the second switch S2 is closed, the part of the series-parallel branch 101 between the input port Rx of the receiving path and the antenna is an equivalent form of a π-type matching network or an equivalent form of a T-type matching network. Or a simplified form; the output port Tx of the transmission path is shorted to the ground; thus the radio frequency reception can be realized. At this time, regardless of the impedance of the low noise amplifier (LNA) connected to the input port Rx of the receiving path when it is turned off, the equivalent form of the π-type matching network can be passed between the antenna and the output port Tx of the transmitting path Or an equivalent or simplified form of a T-shaped matching network, flexibly adjusting the impedance matching between the antenna and the input port Rx of the receiving path.

When the first switch S1 is closed and the second switch S2 is open, the part of the series-parallel branch 101 between the output port Tx of the transmission path and the antenna is a second-order LC impedance matching network or a second-order LC impedance matching network. The equivalent or simplified form; the input port Rx of the receiving path is shorted to the ground; and then the radio frequency transmission can be realized. At this time, regardless of the impedance of the power amplifier (Power amplifier, PA) connected to the output port Tx of the transmission path when it is turned off, the antenna and the input port Rx of the reception path can pass through a second-order LC impedance matching network or a second-order LC impedance matching network. The equivalent or simplified form of the impedance matching network realizes the change of the output impedance between the antenna and the output port Tx of the transmission path.

It can be seen from the above that in the radio frequency transceiver switch circuit provided by the present application, since the first switch S1 and the second switch S2 are respectively arranged between the corresponding points in the series-parallel branch circuit 101 and the ground, they are not connected in series to the radio frequency transceiver circuit. In the signal path of the antenna, the influence of the switch on the radio frequency performance can be avoided. Compared with the existing RF transceiver switch circuit in which the RF transceiver switch is installed in the signal path of the antenna, the insertion loss and the insertion loss caused by the addition of the switch can be further avoided. The problem of deteriorating transceiver performance is to achieve good transceiver performance and time-sharing high-performance work of radio frequency transceiver.

Moreover, since the output port Tx of the transmission path is shorted to the ground when the radio frequency reception is in operation; and the input port Rx of the reception path is shorted to the ground when the radio frequency transmission is in operation; that is, the radio frequency transceiver switch provided by the application The circuit has no requirement on the turn-off impedance of the output port Tx of the transmitting path and the input port Rx of the receiving path, and has wide applicability.

It is worth noting that there is also a radio frequency transceiver switch circuit in the prior art. The radio frequency transceiver switch circuit uses the matching circuit of LNA and PA to cooperate with the switch to switch the transceiver state, avoiding the use of switches composed of MOS tubes on the transceiver path, and then Additional insertion loss can be avoided. However, when the switch is switched, a given condition needs to be met when the LNA or PA is turned off, otherwise the performance of the radio frequency transceiver switching circuit will be deteriorated. However, the RF transceiver switch circuit provided by the present application has no requirements on the output impedance when the LNA or PA is turned off, can ensure the transceiver performance of the RF transceiver switch circuit, and has better versatility. Moreover, the matching circuit of the LNA in the existing radio frequency transceiver switch circuit only uses a single inductor, and the degree of freedom is limited, which is not conducive to wide application. In the RF transceiver switch circuit provided by the present application, the matching circuit is at least the equivalent of a π-type matching network or the equivalent or simplified form of a T-type matching network, which has a good degree of freedom and versatility. Therefore, there is no problem that the matching circuit only uses a single inductor, the degree of freedom is limited, and it is not conducive to wide application.

On the basis of the previous embodiment, another embodiment of the present application provides the following specific forms for the specific structure of the series-parallel branch 101 and the connection relationship between it and the two switches:

Optionally, please refer to FIG. 4. In practical applications, if N=2, the series-parallel branch 101 in the radio frequency transceiver switch circuit may specifically include: a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth Capacitor C4, first inductor L1, second inductor L2 and third inductor L3.

Wherein, one end of the first capacitor C1 is respectively connected to one end of the first inductor L1 and one end of the third capacitor C3, and the connection point is connected to the antenna. Port ANT in FIG. 4 is a port connected to an antenna.

The other end of the first capacitor C1 is connected to one end of the second inductor L2, and the connection points are respectively connected to the first end of the first switch S1 and the input port Rx of the receiving path.

The other end of the second inductor L2 and the other end of the first switch S1 are both grounded.

The other end of the first inductor L1 is respectively connected to the other end of the third capacitor C3, one end of the third inductor L3, one end of the second capacitor C2, one end of the fourth capacitor C4 and the first end of the second switch S2.

Specifically, the common connection point of the first inductor L1, the second switch S2, the second capacitor C2 and the third inductor L3 is point X in the figure.

The other end of the third inductor L3 is respectively connected to the other end of the fourth capacitor C4 and the output port Tx of the transmission channel.

The other end of the second capacitor C2 and the second end of the second switch S2 are both grounded.

It should be noted that the second capacitor C2, the third capacitor L3 and the fourth capacitor C4 in FIG. C1 constitutes another transmit matching unit.

In the actual application process:

When the RF transceiver switch circuit is in the RF receiving working state, the second switch S2 is closed, the first switch S1 is open, and point X is shorted to ground. Therefore, regardless of the impedance of the PA connected to the output port Tx of the transmission path when it is turned off, the antenna and the input port Rx of the reception path form an equivalent π-type matching network, that is, the series-parallel branch 101 is connected to the input port of the reception path. The part between Rx and the antenna is an equivalent π-type matching network, which can flexibly adjust the input impedance matching between the antenna and the input port Rx of the receiving path.

When the radio frequency transceiver switch circuit is in the radio frequency transmission working state, the first switch S1 is closed, the second switch S2 is open, and the input port Rx of the receiving path is shorted to ground. Similarly, without considering the turn-off impedance of the LNA connected to the input port Rx of the receiving path, the antenna and the output port Tx of the transmitting path form an equivalent LC impedance matching network, that is, the series-parallel branch 101 is connected to the output port of the transmitting path The part between Tx and the antenna is an equivalent form of a second-order LC impedance matching network, which can realize impedance transformation between the antenna and the output port Tx of the transmission path.

Since the inductance in the transmission matching unit between the antenna and the output port Tx of the transmission path is connected in parallel with capacitance, as shown in the figure, the third capacitance C3 is connected in parallel with the first inductance L1, and the fourth capacitance is connected in parallel with the third inductance L3 C4, therefore, can further suppress the harmonics of the carrier output, and at the same time, can provide additional harmonic suppression with little increase in cost, thereby omitting off-chip filter components, and can meet the FCC (Federal Communications Commission, U.S. Federal Communications Commission) spectrum emission requirements.

On the basis of FIG. 4 , the carrier frequency f ₀ transmitted by the radio frequency transceiver switching circuit is taken as an example for illustration. After the capacitor C3 and the inductor L1 are connected in parallel, it can ensure that the resonance is at the frequency of the n-order harmonic n*f ₀ (n=2, 3, . . . ), providing an additional level of suppression for the n-order harmonic. Similarly, after the capacitor C4 and the inductor L3 are connected in parallel, it can ensure that the resonance is at the frequency of the n-order harmonic n*f ₀ (n=2, 3, . . . ), providing an additional level of suppression for the n-order harmonic. In practical applications, the specific value of n can be selected according to user needs and application environment. No matter what value n is, it belongs to the protection scope of the present application.

Optionally, please refer to FIG. 5. In practical applications, if N=2, the series-parallel branch 101 in the radio frequency transceiver switch circuit may also specifically include: a first capacitor C1, a second capacitor C2, a third capacitor C3, a Four capacitors C4, fifth capacitor C5, sixth capacitor C6, first inductor L1, second inductor L2 and third inductor L3.

One end of the first capacitor C1 is respectively connected to one end of the second capacitor C2, one end of the second inductor L2 and one end of the fifth capacitor C5, and the connecting point is connected to the antenna. Port ANT in FIG. 5 is a port connected to an antenna.

The other end of the first capacitor C1 is connected to one end of the first inductor L1, and the connection points are respectively connected to the first end of the first switch S1 and one end of the third capacitor C3.

Specifically, the common connection point of the first capacitor C1 , the first inductor L1 , the first switch S1 and the third capacitor C3 is point Y in the figure.

The other end of the third capacitor C3 is connected to the input port Rx of the receiving path.

The other end of the first inductor L1 and the second end of the first switch S1 are both grounded.

The other end of the second inductor L2 is respectively connected to the other end of the fifth capacitor C5, one end of the fourth capacitor C4, the first end of the second switch S2, one end of the sixth capacitor C6 and one end of the third inductor L3.

Specifically, the common connection point of the second inductor L2, the fourth capacitor C4, the second switch S2 and the third inductor L3 is point X in the figure.

The other end of the third inductor L3 is respectively connected to the other end of the sixth capacitor C6 and the output port Tx of the transmission path.

The other end of the second capacitor C2, the other end of the fourth capacitor C4 and the second end of the second switch S2 are all grounded.

It should be noted that the third inductor L3, the sixth capacitor C6 and the fourth capacitor C4 in FIG. 5 constitute a transmission matching unit. When the first switch S1 is closed, the first capacitor C1 and the second capacitor C2 in FIG. 5 are connected in parallel with the second inductor L2 and the fifth capacitor C5 to form another transmitting matching unit.

In practical applications, the working process of the series-parallel branch 101 in the RF transceiver switch circuit shown in FIG. 5 is as follows:

When the radio frequency transceiver switch circuit is in the radio frequency receiving working state, the second switch S2 is closed, the first switch S1 is opened, and the output port Tx of the transmission path is shorted to ground. In this way, regardless of the impedance of the PA connected to the output port Tx of the transmission path when it is turned off, the antenna and the input port Rx of the reception path form an equivalent T-shaped matching network, that is, the series-parallel branch 101 is connected to the input port of the reception path. The part between Rx and the antenna is an equivalent T-shaped matching network, which can flexibly adjust the input impedance matching between the antenna and the LNA connected to the output port Tx of the transmission path.

When the RF transceiver switch circuit is in the RF transmitting working state, the first switch S1 is closed, the second switch S2 is open, and the point Y is shorted to ground. Similarly, there is no need to consider the impedance of the LNA connected to the input port Rx of the receiving path when it is turned off. At this time, the antenna and the output port Tx of the transmitting path form an equivalent LC-type impedance matching network, that is, the series-parallel branch 101 in the transmitting path The part between the output port Tx of the antenna and the equivalent form of the second-order LC impedance matching network can realize the impedance transformation of the output between the antenna and the output port Tx of the transmission path.

Due to this embodiment, the inductance in the transmission matching unit between the antenna and the output port Tx of the transmission path is connected in parallel with a capacitor, such as the fifth capacitor C5 in parallel with the second inductance L2 in the figure, and the third inductance L3 in parallel The sixth capacitor C6, therefore, can further suppress the harmonics of the carrier output, and at the same time, can provide additional harmonic suppression with little increase in cost, thereby omitting off-chip filter components, and can meet the FCC spectrum launch request.

On the basis of FIG. 5 , the carrier frequency f ₀ transmitted by the radio frequency transceiver switching circuit is taken as an example for illustration. After the capacitor C5 and the inductor L2 are connected in parallel, it can ensure that the resonance is at the frequency of the n-order harmonic n*f ₀ (n=2, 3, . . . ), providing an additional level of suppression for the n-order harmonic. Similarly, after the capacitor C6 and the inductor L3 are connected in parallel, it can ensure that the resonance is at the frequency of the n-order harmonic n*f ₀ (n=2, 3, . . . ), providing an additional level of suppression for the n-order harmonic. In practical applications, the specific value of n can be selected according to user needs and application environment. No matter what value n is, it belongs to the protection scope of the present application.

Optionally, please refer to FIG. 6. In practical applications, if N=1, the series-parallel branch 101 in the radio frequency transceiver switch circuit specifically includes: a first capacitor C1, a second capacitor C2, a fifth capacitor C5, a first inductor L1 and the second inductor L2.

Wherein, one end of the first capacitor C1 is respectively connected to one end of the second capacitor C2, one end of the fifth capacitor C5 and one end of the second inductor L2, and the connecting point is connected to the antenna.

The other end of the first capacitor C1 is connected to one end of the first inductor L1, and the connection points are respectively connected to the first end of the first switch S1 and the input port Rx of the receiving channel. Port ANT in FIG. 6 is a port connected to an antenna.

The other end of the first inductor L1 and the second end of the first switch S1 are both grounded.

The other end of the second inductor L2 is respectively connected to the other end of the fifth capacitor C5, the first end of the second switch S2 and the output port Tx of the transmission path.

The other end of the second capacitor C2 and the second end of the second switch S2 are both grounded.

It should be noted that, in order to make the radio frequency transceiver switch circuit more integrated, the radio frequency transceiver switch circuit provided in this embodiment is based on the radio frequency transceiver switch circuit provided in the embodiment corresponding to FIG. capacitors (the third inductor L3, the third capacitor C3, the fourth capacitor C4 and the sixth capacitor C6 in FIG. 5). In this way, not only can components be saved, but also the layout area and manufacturing cost can be reduced when the radio frequency transceiver switching circuit is integrated on the chip, and the integration degree of the radio frequency transceiver switching circuit can be improved.

It should also be noted that when the first switch S1 is closed, the first capacitor C1 is connected in parallel with the second capacitor C2 and then forms a transmission matching unit with the second inductor L2 and the fifth capacitor C5.

In practical applications, the working process of the series-parallel branch 101 in the RF transceiver switch circuit shown in FIG. 6 is as follows:

When the radio frequency transceiver switch circuit is in the radio frequency receiving working state, the second switch S2 is closed, the first switch S1 is opened, and the output port Tx of the transmission path is shorted to ground. The antenna and the input port Rx of the receiving path form an equivalent LC-type matching network, that is, the part of the series-parallel branch 101 between the input port Rx of the receiving path and the antenna is the simplified equivalent LC impedance of the π-type matching network matching network.

When the radio frequency transceiver switch circuit is in the radio frequency transmission working state, the first switch S1 is closed, the second switch S2 is open, and the input port Rx of the receiving path is shorted to ground. At this time, the antenna and the output port Tx of the transmission path form an equivalent LC-type impedance matching network, that is, the part of the series-parallel branch 101 between the output port Tx of the transmission path and the antenna is a simplified second-order LC impedance matching network The subsequent equivalent LC impedance matching network can realize the output impedance transformation between the antenna and the output port Tx of the transmission path.

Due to this embodiment, the inductance in the transmission matching unit between the antenna and the output port Tx of the transmission path is connected in parallel with a capacitor, such as the fifth capacitor C5 connected in parallel with the second inductance L2 in the figure, therefore, in order to further suppress Harmonics of the carrier output. At the same time, it can also provide additional harmonic suppression with little increase in cost, thereby omitting off-chip filter components, and can meet the spectrum emission requirements of the FCC.

On the basis of FIG. 6 , the carrier frequency f ₀ transmitted by the radio frequency transceiver switching circuit is taken as an example for illustration. After the capacitor C5 and the inductor L2 are connected in parallel, it can ensure that the resonance is at the frequency of the n-order harmonic n*f ₀ (n=2, 3, . . . ), providing an additional level of suppression for the n-order harmonic.

Optionally, please refer to FIG. 7. In practical applications, N=1, and the series-parallel branch 101 in the radio frequency transceiver switch circuit specifically includes: a first capacitor C1, a second capacitor C2, a third capacitor C3, and a first inductor L1 and the second inductor L2.

One end of the first capacitor C1 is respectively connected to one end of the first inductor L1 and one end of the third capacitor C3, and the connection point is connected to the antenna. Port ANT in FIG. 7 is a port connected to an antenna.

The other end of the first capacitor C1 is connected to one end of the second inductor L2, and the connection points are respectively connected to the first end of the first switch S1 and the input port Rx of the receiving channel.

The other end of the second inductor L2 and the second end of the first switch S1 are both grounded.

The other end of the first inductor L1 is respectively connected to the other end of the third capacitor C3, one end of the second capacitor C2, the first end of the second switch S2 and the output port Tx of the transmission channel.

Specifically, the common connection point of the first inductor L1, the second capacitor C2 and the second switch S2 is point X in the figure.

The other end of the second capacitor C2 and the second end of the second switch S2 are both grounded.

It should be noted that, in order to make the RF transceiver switch circuit more integrated, the RF transceiver switch circuit provided in this embodiment reduces an inductor and a Capacitors (the third inductor L3 and the fourth capacitor C4 in FIG. 4 ) can not only save components, but also reduce the layout area when the RF transceiver switching circuit is integrated on-chip, and improve the integration degree of the RF transceiver switching circuit.

It should also be noted that when the first switch S1 is closed, the first capacitor C1, the first inductor L1 and the third capacitor C3 form a transmission matching unit, and at this time the series-parallel branch 101 is connected to the antenna at the output port Tx of the transmission path In the matching network part between, the second capacitor C2 is used as a device other than the emission matching unit.

In practical applications, the working process of the series-parallel branch 101 in the RF transceiver switch circuit shown in FIG. 7 is as follows:

When the radio frequency transceiver switch circuit is in the radio frequency receiving working state, the second switch S2 is closed, the first switch S1 is opened, and the output port Tx of the transmission path is shorted to ground. Therefore, regardless of the impedance of the PA connected to the output port Tx of the transmission path when it is turned off, the antenna and the input port Rx of the reception path form an equivalent π-type matching network, that is, the series-parallel branch 101 is connected to the input port of the reception path. The part between Rx and the antenna is an equivalent π-type matching network, which can flexibly adjust the impedance matching between the antenna and the LNA input.

When the radio frequency transceiver switch circuit is in the radio frequency transmission working state, the first switch S1 is closed, the second switch S2 is open, and the input port Rx of the receiving path is shorted to ground. Therefore, the antenna and the output port Tx of the transmission path form an equivalent π-type impedance matching network, that is, the part of the series-parallel branch 101 between the output port Tx of the transmission path and the antenna is a simplified second-order LC impedance matching network The equivalent π-type matching network can realize the impedance transformation and filtering of the output between the antenna and the output port Tx of the transmission path.

Due to this embodiment, the inductance in the transmission matching unit between the antenna and the output port Tx of the transmission path is connected in parallel with a capacitor, such as the third capacitor C3 in parallel with the first inductance L1 in the figure, therefore, it can be ensured that the resonance is at At the frequency of the n-order harmonic n*f ₀ (n=2, 3, . . . ), an additional level of suppression is provided for the n-order harmonic, further reducing the requirements for off-chip filter components.

Optionally, the embodiment of the present application also provides a radio frequency front-end circuit, please refer to FIG. 8 , the front-end circuit mainly includes: a receiving path 201, a transmitting path 203, and a radio frequency transceiver switch circuit 202 as provided in any of the above-mentioned embodiments.

Wherein, the receiving channel 201 includes an LNA inside, and the LNA is mainly used to amplify the radio frequency signal of the receiving channel.

The transmit channel 203 includes a PA inside, and the PA is mainly used to amplify radio frequency signals of the transmit channel.

It should be noted that the radio frequency front-end circuit is the core component of the mobile communication system, which mainly plays the role of sending and receiving radio frequency signals, and generally consists of four parts: PA, radio frequency switch, filter and LNA.

Among them, the radio frequency switch is mainly used to realize the switching between the receiving and transmitting of the radio frequency signal, and the switching between different frequency bands. Filters are mainly used to retain signals within a specific frequency band and filter out signals outside a specific frequency band.

In practical applications, a duplexer can also be added in the radio frequency front-end circuit to realize the isolation of the transmitted and received signals.

It should also be noted that, in addition to the devices described above, the radio frequency front-end circuit can also be equipped with other devices. For the configuration of each device in the radio frequency front-end circuit, please refer to the prior art. The scope of protection applied for.

In this embodiment, after the radio frequency transceiver switch circuit 202 is set in the radio frequency front-end circuit, because the radio frequency transceiver switch circuit 202 has the characteristics of strong versatility, high integration, good transceiver performance, reliable and stable operation, etc., a radio frequency transceiver circuit 202 is provided. The radio frequency front-end circuit of the switch circuit 202 can not only ensure that the receiving path 201 and the transmitting path 203 are switched and connected to the antenna, but also can further improve the working stability of the radio frequency front-end circuit.

Optionally, the embodiment of the present application also provides a radio frequency transceiver, please refer to FIG. FIG. 9 only shows the case where the number of transmitting front-end circuits 203 is 1).

In practical applications, the antenna 301 cooperates with the radio frequency front-end circuit 302 to enable the radio frequency transceiver to realize radio frequency transceiving function; the baseband circuit is used to process the frequency signal captured by the antenna.

It should be noted that, for the relevant description of the radio frequency front-end circuit 302, reference may be made to the embodiment corresponding to FIG. 8 , which will not be repeated here.

It should also be noted that the relevant description of the radio frequency transceiver can also refer to the prior art, which will not be repeated in this application, and all of them belong to the protection scope of this application.

The features recorded in the various embodiments in this specification can be replaced or combined with each other, and the same and similar parts of the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for related parts, please refer to the part of the description of the method embodiment. The systems and system embodiments described above are only illustrative, and the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is It can be located in one place, or it can be distributed to multiple network elements. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. It can be understood and implemented by those skilled in the art without creative effort.

Professionals can further realize that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software or a combination of the two. In order to clearly illustrate the possible For interchangeability, in the above description, the composition and steps of each example have been generally described according to their functions. Whether these functions are executed by hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may use different methods to implement the described functions for each specific application, but such implementation should not be regarded as exceeding the scope of the present invention.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

It should also be noted that in this article, relational terms such as first and second etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations Any such actual relationship or order exists between. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

Claims (8)

1. A radio frequency transceiver switch circuit, characterized in that it comprises: a series-parallel branch, a first switch and a second switch; wherein: The series-parallel branches are respectively connected to the input port of the receiving path, the output port of the transmitting path, and the antenna; The first switch and the second switch are respectively arranged between corresponding points in the series-parallel branch and ground; When the first switch is opened and the second switch is closed, the output port of the transmitting path is shorted to ground; the connection between the input port of the receiving path and the antenna of the series-parallel branch is The part is the corresponding matching network; the part between the input port of the receiving path and the antenna of the series-parallel branch is the equivalent form of the π-type matching network or the equivalent or simplified version of the T-type matching network form; When the first switch is closed and the second switch is opened, the input port of the receiving path is shorted to ground; the connection between the output port of the transmitting path and the antenna of the series-parallel branch is part, at least including: a transmission matching unit, or N transmission matching units connected in series in sequence, N being a positive integer greater than 1; the series-parallel branch is between the output port of the transmission path and the antenna The part of is a second-order LC impedance matching network or an equivalent or simplified form of a second-order LC impedance matching network; The emission matching unit includes: two capacitors and an inductance; the inductance is connected in parallel with one of the capacitors, and one end of the parallel connection is grounded through the other capacitor, and is used as the output end of the emission matching unit for connecting The input end of the antenna or the latter transmission matching unit; the other end of the parallel connection is used as the input end of the transmission matching unit, and is used to connect the output end of the previous transmission matching unit or the output port of the transmission path ; The second switch is arranged between any point on the series branch of the N transmitting matching units and ground. 2. The radio frequency transceiver switch circuit according to claim 1, wherein N=2, the series-parallel branch comprises: a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first inductor, a second inductance and a third inductance; One end of the first capacitor is respectively connected to one end of the first inductor and one end of the third capacitor, and the connection point is connected to the antenna; The other end of the first capacitor is connected to one end of the second inductor, and the connection points are respectively connected to the first end of the first switch and the input port of the receiving path; The other end of the second inductor and the other end of the first switch are grounded; The other end of the first inductor is respectively connected to the other end of the third capacitor, one end of the third inductor, one end of the second capacitor, one end of the fourth capacitor and the second switch. connected to the first end; The other end of the third inductor is respectively connected to the other end of the fourth capacitor and the output port of the transmission path; The other end of the second capacitor and the second end of the second switch are both grounded. 3. The radio frequency transceiver switch circuit according to claim 1, wherein N=1, and the series-parallel branch comprises: a first capacitor, a second capacitor, a third capacitor, a first inductor, and a second inductor; One end of the first capacitor is respectively connected to one end of the first inductor and one end of the third capacitor, and the connection point is connected to the antenna; The other end of the first capacitor is connected to one end of the second inductor, and the connection points are respectively connected to the first end of the first switch and the input port of the receiving path; The other end of the second inductor and the second end of the first switch are both grounded; The other end of the first inductor is respectively connected to the other end of the third capacitor, one end of the second capacitor, the first end of the second switch, and the output port of the transmission path; The other end of the second capacitor and the second end of the second switch are both grounded. 4. The radio frequency transceiver switch circuit according to claim 1, wherein N=2, the series-parallel branch comprises: a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first inductor, a second inductor and a third inductor; One end of the first capacitor is respectively connected to one end of the second capacitor, one end of the second inductor and one end of the fifth capacitor, and the connection point is connected to the antenna; The other end of the first capacitor is respectively connected to one end of the first inductor, the first end of the first switch, and one end of the third capacitor; The other end of the third capacitor is connected to the input port of the receiving path; The other end of the first inductor and the second end of the first switch are both grounded; The other end of the second inductor is respectively connected to the other end of the fifth capacitor, one end of the fourth capacitor, the first end of the second switch, one end of the sixth capacitor, and the third capacitor. One end of the inductor is connected; The other end of the third inductor is respectively connected to the other end of the sixth capacitor and the output port of the transmission path; The other end of the second capacitor, the other end of the fourth capacitor and the second end of the second switch are all grounded. 5. The radio frequency transceiver switch circuit according to claim 1, wherein N=1, the series-parallel branch comprises: a first capacitor, a second capacitor, a fifth capacitor, a first inductor, and a second inductor; One end of the first capacitor is respectively connected to one end of the second capacitor, one end of the fifth capacitor and one end of the second inductor, and the connection point is connected to the antenna; The other end of the first capacitor is connected to one end of the first inductor, and the connection points are respectively connected to the first end of the first switch and the input port of the receiving path; The other end of the first inductor and the second end of the first switch are both grounded; The other end of the second inductor is respectively connected to the other end of the fifth capacitor, the first end of the second switch, and the output port of the transmission path; The other end of the second capacitor and the second end of the second switch are both grounded. 6. The radio frequency transceiver switch circuit according to any one of claims 1-5, wherein the first switch and the second switch are both electronic switches. 7. A radio frequency front-end circuit, characterized by comprising: a receiving path, a transmitting path, and the radio frequency transceiver switch circuit according to any one of claims 1-6. 8. A radio frequency transceiver, comprising: an antenna and at least one radio frequency front-end circuit according to claim 7.

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