CN216356718U

CN216356718U - Communication circuit and mobile terminal

Info

Publication number: CN216356718U
Application number: CN202123300360.8U
Authority: CN
Inventors: 陈朝喜
Original assignee: Beijing Xiaomi Mobile Software Co Ltd
Current assignee: Beijing Xiaomi Mobile Software Co Ltd
Priority date: 2021-12-23
Filing date: 2021-12-23
Publication date: 2022-04-19
Anticipated expiration: 2031-12-23

Abstract

The present disclosure relates to a communication circuit and a mobile terminal. The communication circuit (100) comprises: the middle frame antenna (10) is connected with a middle frame of the terminal and used for receiving and transmitting radio frequency signals; the radio frequency front end (40) is arranged in a radio frequency communication link where the middle frame antenna (10) is located; a static protection circuit (50) disposed in a radio frequency communication link between the center frame antenna (10) and the radio frequency front end (40) for reducing static electricity transmitted from the center frame antenna (10) to the radio frequency front end (40). Thus, when static electricity is input from the middle frame antenna (10), the static electricity protection circuit (50) is arranged on the front path in the radio frequency communication link, so that the risk of communication circuit breakdown caused by the static electricity is effectively reduced, and the reliability is high.

Description

Communication circuit and mobile terminal

Technical Field

The present disclosure relates to the field of mobile terminal technologies, and in particular, to a communication circuit and a mobile terminal.

Background

In the related art, a middle frame of a mobile terminal is provided with one or more antennas. The middle frame antenna back stage is connected with an antenna tuner (tuner) which is linked to a radio frequency front end or a modem (modem) through a high speed control line and a radio frequency path for communication control. If the middle frame is made of metal, the terminal is at risk of static electricity introduced by the middle frame antenna, and when the static electricity is transmitted to the inside of the mobile terminal through the middle frame antenna, the static electricity is conducted to the modem through a control line of the antenna tuner, so that a modem crash (crash) phenomenon is easily caused.

SUMMERY OF THE UTILITY MODEL

To overcome the problems in the related art, the present disclosure provides a communication circuit including:

the middle frame antenna is connected with a middle frame of the terminal and used for receiving and transmitting radio frequency signals;

the radio frequency front end is arranged in a radio frequency communication link where the middle frame antenna is positioned;

and the electrostatic protection circuit is arranged in a radio frequency communication link between the middle frame antenna and the radio frequency front end and is used for reducing static electricity transmitted from the middle frame antenna to the radio frequency front end.

Optionally, the communication circuit further includes an antenna tuner and a modem, where the antenna tuner is connected to the middle frame antenna, the modem, and the radio frequency front end is connected to the modem, and the modem is configured to control the antenna tuner to modulate and demodulate signals in the radio frequency communication link.

The electrostatic protection circuit is connected with any one of the following parts: a node between the antenna tuner and the modem, a node between the midframe antenna and the antenna tuner, and a node between the antenna tuner and the radio frequency front end.

Optionally, the electrostatic protection circuit comprises a transient voltage suppression diode TVS.

Optionally, an anode of the TVS is connected to a node between the antenna tuner and the modem, and a cathode of the TVS is connected to a ground line.

Optionally, an anode of the TVS is connected to a node between the middle frame antenna and the antenna tuner, and a cathode of the TVS is connected to a ground line.

Optionally, an anode of the TVS is connected to a node between the antenna tuner and the rf front end, and a cathode of the TVS is connected to a ground line.

Optionally, the electrostatic protection circuit comprises a filter circuit, a varistor or a gas discharge tube.

Optionally, the filter circuit is an LC filter circuit, a first inductor in the LC filter circuit is connected between the antenna tuner and the modem, and one end of a first capacitor in the LC filter circuit is connected to the antenna tuner and the other end is connected to the ground.

Optionally, the filter circuit is an LC filter circuit, a second inductor in the LC filter circuit is connected between the middle frame antenna and the antenna tuner, one end of a second capacitor in the LC filter circuit is connected to the middle frame antenna, and the other end is connected to a ground line.

Optionally, the filter circuit is an LC filter circuit, a third inductor in the LC filter circuit is connected between the antenna tuner and the radio frequency front end, one end of a third capacitor in the LC filter circuit is connected to the antenna tuner, and the other end of the third capacitor is connected to a ground line.

The present disclosure also provides a mobile terminal, which includes the above communication circuit provided by the present disclosure.

The technical scheme provided by the embodiment of the disclosure can have the following beneficial effects:

the electrostatic protection circuit is arranged in the radio frequency communication link between the middle frame antenna and the radio frequency front end, namely when static electricity is input from the middle frame antenna, the electrostatic protection circuit is arranged on a front path in the radio frequency communication link to reduce the static electricity transmitted from the middle frame antenna to the radio frequency communication link, so that the risk of communication circuit breakdown caused by the static electricity is effectively reduced, and the reliability is high.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.

Fig. 1 is a block diagram illustrating a structure of a communication circuit according to an exemplary embodiment.

Fig. 2 is a block diagram illustrating a structure of a communication circuit according to another exemplary embodiment.

Fig. 3 is a block diagram illustrating a structure of a communication circuit according to yet another exemplary embodiment.

Fig. 4 is a block diagram illustrating a structure of a communication circuit according to yet another exemplary embodiment.

Fig. 5 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment.

Fig. 6 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment.

Fig. 7 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment.

Fig. 8 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment.

Fig. 9 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment.

Fig. 10 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

Fig. 1 is a block diagram illustrating a structure of a communication circuit according to an exemplary embodiment. As shown in fig. 1, the communication circuit 100 includes a middle frame antenna 10, a radio frequency front end 40, and an electrostatic protection circuit 50.

The middle frame antenna 10 is connected to a middle frame of the terminal, and is configured to receive and transmit radio frequency signals. The radio frequency front end 40 is arranged in the radio frequency communication link in which the center antenna 10 is located. The electrostatic protection circuit 50 is disposed in the rf communication link between the center antenna 10 and the rf front end 40, and is configured to reduce the static electricity transmitted from the center antenna 10 to the rf front end 40.

The center antenna 10 is an antenna connected to a center of the terminal. The middle frame is an area connected between the front panel and the rear cover of the terminal, and if the terminal is a mobile phone, a card slot, a key, an interface and the like are usually arranged on the middle frame. The static electricity is conducted through the center antenna into the radio frequency communication link, which is a link including the center antenna 10 and the radio frequency front end 40 for transmitting radio frequency signals.

A Radio Frequency Front-End (RFFE) is a core component of a mobile communication system, and includes Power Amplifiers (PA), duplexers (duplex and duplex), Radio Frequency switches (Switch), filters (Filter), low-noise amplifiers (LNA), Radio Frequency transceivers (Transceiver), Band Pass Filters (BPF), and so on. The structure of the rf front end is well known in the art and will not be described herein.

Through the technical scheme, the electrostatic protection circuit is arranged in the radio frequency communication link between the middle frame antenna and the radio frequency front end, namely when static electricity is input from the middle frame antenna, the electrostatic protection circuit is arranged on a front path in the radio frequency communication link to reduce the static electricity transmitted from the middle frame antenna to the radio frequency communication link, so that the risk of breakdown of the communication circuit caused by the static electricity is effectively reduced, and the reliability is high.

Fig. 2-4 are block diagrams of the structures of communication circuits shown according to three exemplary embodiments, respectively. As shown in fig. 2, the communication circuit 100 further includes an antenna tuner 20 and a modem 30 on the basis of fig. 1. The antenna tuner 20 is connected to the center antenna 10, the modem 30, and the rf front end 40 is connected to the modem 30. The modem 30 is used for controlling the antenna tuner 20 to modulate and demodulate signals in the radio frequency communication link.

The electrostatic protection circuit 50 is connected to any one of the following: a node between the antenna tuner 20 and the modem 30, a node between the middle frame antenna 10 and the antenna tuner 20, and a node between the antenna tuner 20 and the radio frequency front end 40.

The modem 30 may be disposed inside a Central Processing Unit (CPU) (not shown in fig. 1) or may be external to the CPU.

In fig. 2, the electrostatic protection circuit 50 is connected to a node between the antenna tuner 20 and the modem 30, in fig. 3, the electrostatic protection circuit 50 is connected to a node between the center antenna 10 and the antenna tuner 20, and in fig. 4, the electrostatic protection circuit 50 is connected to a node between the antenna tuner 20 and the radio frequency front end 40.

In one embodiment, the esd protection circuit 50 may include a Transient Voltage suppression diode (TVS). Fig. 5 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment. In the embodiment of fig. 5, the esd protection circuit 50 may include a first TVS D1, an anode of the first TVS D1 connected to a node between the antenna tuner 20 and the modem 30, and a cathode of the first TVS D1 connected to ground.

The TVS is started only when a certain starting voltage is reached, so that the static electricity interfering the incoming can be introduced into a signal ground of the middle frame, and the interference of a rear-stage radio frequency communication link is prevented. It should be noted that, because the TVS has parasitic capacitance and the mipi protocol is used by the modem control antenna tuner, the signal rate of transmission is high, and therefore, the TVS should be selected to meet the signal integrity requirement of the mipi high-speed signal.

Fig. 6 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment. In the embodiment of fig. 6, the esd protection circuit 50 may include a second TVS D2, an anode of the second TVS D2 is connected to a node between the middle frame antenna 10 and the antenna tuner 20, and a cathode ground of the second TVS D2, i.e., a TVS is designed at the middle frame antenna end. Because TVS has parasitic capacitance, TVS with smaller capacitance value of parasitic capacitance should be selected, and meanwhile, when the middle frame antenna is debugged and matched, the TVS should be added to debug, so that the TVS is prevented from influencing the matching of the antenna frequency band.

Fig. 7 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment. In the embodiment of fig. 7, the esd protection circuit 50 may include a third TVS D3, an anode of the third TVS D3 being connected to the node between the antenna tuner 20 and the rf front end 40, and a cathode of the third TVS D3 being connected to the ground. Similarly, a TVS with a smaller parasitic capacitance should be selected, and the radio frequency front end 40 should add the TVS to debug during debugging and matching, so as to prevent the TVS from affecting matching of the radio frequency band. Moreover, since the TVS is a nonlinear device, it may mix with the frequency band transmitted by the rf communication link to generate, for example, a third harmonic or a fifth harmonic, i.e., a third-order intermodulation or a fifth-order intermodulation, for which a filter circuit for the third-order intermodulation and the fifth-order intermodulation of the rf channel frequency should be reserved for the rf communication link.

In yet another embodiment, the electrostatic protection circuit 50 may include a filter circuit, a voltage dependent resistor, or a gas discharge tube, all of which are capable of functioning to protect against static electricity.

Fig. 8 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment. In the embodiment of fig. 8, the filter circuit is an LC filter circuit, and the filter circuit includes a first inductor L1 and a first capacitor C1. The first inductor L1 is connected between the antenna tuner 20 and the modem 30, and one end of the first capacitor C1 is connected to the antenna tuner 20, and the other end is connected to the ground.

Because the electrostatic interference frequency has a certain frequency band, the impedance to the ground in the electrostatic interference frequency band can be lower by selecting the LC filter circuit, and the impedance to the static can be maximum by the inductance in the LC filter circuit, so that the signal loss to the normal transmission is smaller. In this embodiment, the transmission of static electricity can be blocked from the radio frequency communication link between the antenna tuner 20 and the modem 30, which are relatively front.

Fig. 9 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment. In the embodiment of fig. 9, the filter circuit is an LC filter circuit, and the filter circuit includes a second inductor L2 and a second capacitor C2. The second inductor L2 is connected between the center antenna 10 and the antenna tuner 20, and one end of the second capacitor C2 is connected to the center antenna 10 and the other end is connected to the ground.

The LC filter circuit with appropriate parameters can be selected so that the added LC filter circuit does not affect the matching of the middle frame antenna, i.e., does not affect each performance index in each frequency band of the middle frame antenna. In this embodiment, the transmission of static electricity can be blocked from the radio frequency communication link between the center antenna 10 and the antenna tuner 20 that are relatively front.

Fig. 10 is a schematic diagram of a communication circuit shown in accordance with yet another exemplary embodiment. In the embodiment of fig. 10, the filter circuit is an LC filter circuit, and the filter circuit includes a third inductor L3 and a third capacitor C3. The third inductor L3 is connected between the antenna tuner 20 and the rf front end 40, and one end of the third capacitor C3 is connected to the antenna tuner 20, and the other end is connected to the ground. In this embodiment, the transmission of static electricity can be blocked from the rf communication link between the antenna tuner 20 and the rf front end 40, which are relatively front.

The filter circuit in the present disclosure may be of a crosstalk communication link, i.e. a high impedance state for the interfering signal frequency band.

The present disclosure also provides a mobile terminal including the above communication circuit 100 provided by the present disclosure.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure. This application is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

It will be understood that the present disclosure is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A communication circuit, characterized in that the communication circuit (100) comprises:

the middle frame antenna (10) is connected with a middle frame of the terminal and used for receiving and transmitting radio frequency signals;

the radio frequency front end (40) is arranged in a radio frequency communication link where the middle frame antenna (10) is located;

a static protection circuit (50) disposed in a radio frequency communication link between the center frame antenna (10) and the radio frequency front end (40) for reducing static electricity transmitted from the center frame antenna (10) to the radio frequency front end (40).

2. The communication circuit according to claim 1, wherein the communication circuit (100) further comprises an antenna tuner (20) and a modem (30), the antenna tuner (20) is respectively connected to the center antenna (10), the modem (30) and the radio frequency front end (40), the radio frequency front end (40) is connected to the modem (30), wherein the modem (30) is configured to control the antenna tuner (20) to modulate and demodulate signals in the radio frequency communication link;

the electrostatic protection circuit (50) is connected with any one of the following components: a node between the antenna tuner (20) and the modem (30), a node between the midframe antenna (10) and the antenna tuner (20), a node between the antenna tuner (20) and the radio frequency front end (40).

3. The communication circuit according to claim 2, wherein the electrostatic protection circuit (50) comprises a transient voltage suppression diode TVS.

4. The communication circuit of claim 3, wherein an anode of the TVS is connected to a node between the antenna tuner (20) and the modem (30), and a cathode of the TVS is connected to ground.

5. The communication circuit of claim 3, wherein an anode of the TVS is connected to a node between the center antenna (10) and the antenna tuner (20), and a cathode of the TVS is connected to ground.

6. The communication circuit of claim 3, wherein an anode of the TVS is connected to a node between the antenna tuner (20) and the radio frequency front end (40), and a cathode of the TVS is connected to ground.

7. The communication circuit according to claim 2, wherein the electrostatic protection circuit (50) comprises a filter circuit, a varistor or a gas discharge tube.

8. The communication circuit according to claim 7, wherein the filter circuit is an LC filter circuit, a first inductor of the LC filter circuit is connected between the antenna tuner (20) and the modem (30), and a first capacitor of the LC filter circuit is connected to the antenna tuner (20) at one end and to ground at the other end.

9. The communication circuit according to claim 7, wherein the filter circuit is an LC filter circuit, a second inductor of the LC filter circuit is connected between the middle frame antenna (10) and the antenna tuner (20), and a second capacitor of the LC filter circuit has one end connected to the middle frame antenna (10) and the other end connected to the ground.

10. The communication circuit according to claim 7, wherein the filter circuit is an LC filter circuit, a third inductor of the LC filter circuit is connected between the antenna tuner (20) and the rf front end (40), and a third capacitor of the LC filter circuit has one end connected to the antenna tuner (20) and the other end connected to ground.

11. A mobile terminal, characterized in that the mobile terminal comprises a communication circuit (100) according to any of claims 1-10.