WO2013131230A1

WO2013131230A1 - Antenna switching circuit and wireless terminal device

Info

Publication number: WO2013131230A1
Application number: PCT/CN2012/071928
Authority: WO
Inventors: 彭勇; 景丰华
Original assignee: 华为终端有限公司
Priority date: 2012-03-05
Filing date: 2012-03-05
Publication date: 2013-09-12
Also published as: CN103384962A; CN103384962B

Abstract

Embodiments of the present invention provide an antenna switching circuit and a wireless terminal device. The device comprises a radio frequency input port, a detection port, a built-in antenna and a radio frequency connector, and further comprises: a detection circuit, for forming a direct current detection loop when the radio frequency connector is in communication with an external antenna to form a radio frequency channel, so that the detection port acquires direct current voltage change in the radio frequency channel of the direct current detection loop; and a changeover switch circuit, comprising an input end connected with the radio frequency input port, a control end connected with the detection port, and two output ends respectively connected with the radio frequency connector and the built-in antenna, the changeover switch circuit being used for switching connection relations between the input end and two output ends according to the direct current voltage change acquired by the detection port. In the present invention, through the characteristic that the external antenna uses the direct current, switching is performed automatically between the built-in antenna and the external antenna by using the detection circuit and the switch circuit, so as to ensure continuous communication.

Description

Antenna switching circuit and wireless terminal equipment

TECHNICAL FIELD Embodiments of the present invention relate to wireless communication technologies, and in particular, to an antenna switching circuit and a wireless terminal device. BACKGROUND OF THE INVENTION Setting an antenna on a wireless communication device is a basic structure for implementing wireless communication, and an external antenna is generally connected to an internal device of the wireless communication device through a radio frequency connector. Many wireless communication devices, especially wireless terminal devices, use RF connectors to transmit RF signals between internal devices and external antennas.

However, there are some defects in the above-mentioned RF antenna connection structure, and the RF connector is often used in a situation where no one is watching or inside the casing, such as a power communication wireless communication device. When the RF connector is loose or disconnected, the communication quality will be seriously degraded, and the RF signal will not be transmitted and received normally, which will affect normal wireless communication. SUMMARY OF THE INVENTION Embodiments of the present invention provide an antenna switching circuit and a wireless terminal device to prevent normal wireless communication from being affected by disconnection of a radio frequency connector.

The embodiment of the present invention provides an antenna switching circuit, including a radio frequency input port, a detection port, an internal antenna, and an RF connector. The switching circuit further includes:

a detecting circuit, configured to form a DC detecting loop when the RF connector is connected to the external antenna to form an RF channel, so that the detecting port acquires a DC voltage change in the RF channel in the DC detecting loop;

a switch circuit comprising: an input coupled to the RF input port, a control coupled to the detection port, a first output coupled to the RF connector, and a second output coupled to the internal antenna The switching circuit is configured to switch a connection relationship between the input end and the two output ends according to a DC voltage change acquired by the detecting port.

The embodiment of the invention further provides another antenna switching circuit, including a radio frequency input port, and a check The switching circuit further includes: a detecting circuit, configured to form a DC detecting loop when the RF connector is connected to the external antenna to form an RF channel, so that the detecting port is obtained DC voltage change in the RF channel in the DC detection loop;

An inverter, an input end of the inverter is connected to the detection port;

a switch circuit comprising: an input connected to the RF input port, a first control terminal connected to the detection port, a second control terminal connected to the inverter output terminal, and the RF connector a first output end, and a second output end connected to the built-in antenna, the switch circuit is configured to switch the input end and the two according to a DC voltage change acquired by the detection port and the inverter output end The connection relationship of the output.

The embodiment of the present invention further provides a wireless terminal device, including a radio frequency input port, a detection port, a radio frequency connector, and a built-in antenna, where the wireless terminal device further includes:

a detecting circuit, configured to form a DC detecting loop when the RF connector is connected to the external antenna to form an RF channel, so that the detecting port obtains a direct voltage change in the RF channel in the DC detecting loop;

The embodiment of the present invention further provides another wireless terminal device, including a radio frequency input port, a detection port, a radio frequency connector, and a built-in antenna. The wireless terminal device further includes:

An inverter, an input end of the inverter is connected to the detection port;

a switch circuit comprising: an input connected to the RF input port, a first control terminal connected to the detection port, a second control terminal connected to the inverter output terminal, and the RF connector a first output end, and a second output end connected to the internal antenna, the switch circuit is configured to switch the input end according to a DC voltage change acquired by the detection port and the inverter output end The connection relationship with the two outputs. The antenna switching circuit and the wireless terminal device provided by the embodiments of the present invention can automatically monitor the connection relationship between the external antenna and the RF connector by using the detection circuit to realize the connection between the external antenna and the RF connector, and automatically switch through the switch circuit. Switch the connection between the built-in antenna and the external antenna to avoid the impact on communication. 1 is a schematic structural diagram of an antenna switching circuit according to Embodiment 1 of the present invention;

2 is a schematic structural diagram of an antenna switching circuit according to Embodiment 2 of the present invention;

3 is a schematic structural diagram of an antenna switching circuit according to Embodiment 3 of the present invention;

4 is a schematic structural diagram of an antenna switching circuit according to Embodiment 4 of the present invention;

FIG. 5 is a schematic structural diagram of an antenna switching circuit according to Embodiment 5 of the present invention; FIG.

6 is a schematic diagram of a path of a radio frequency input port connected to an external antenna according to Embodiment 5 of the present invention; FIG. 7 is a schematic diagram of a path of a radio frequency input port connecting an internal antenna according to Embodiment 5 of the present invention; FIG. 8 is an antenna according to Embodiment 6 of the present invention; The structure of the switching circuit is schematic. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a schematic structural diagram of an antenna switching circuit according to Embodiment 1 of the present invention. The antenna switching circuit can be applied to various types of wireless communication devices, such as wireless terminal devices such as mobile phones and power gateways.

The antenna switching circuit of this embodiment includes a radio frequency input port 10 for inputting a radio frequency signal, a detecting port 80, a radio frequency connector 30 for connecting the external antenna 20, and an internal antenna 40, and the external antenna 20 is connected to the radio frequency connector 30. To form an RF channel.

Generally, the external antenna 20 can be detachably connected to the RF connector 30, and in particular, the external antenna is connected to the RF connector 30, for example, through a connector to the RF connector 30. Alternatively, the external antenna 20 can be soldered to the RF connector 30 or to the RF connector 30 via a RF cable. The built-in antenna 40 is an antenna provided in a wireless communication device.

The antenna switching circuit provided in this embodiment further includes a detecting circuit 50 and a switching switch circuit 60.

The detecting circuit 50 is configured to form a DC detecting loop when the RF connector 30 communicates with the external antenna 20 to form an RF channel, so that the detecting port 80 acquires the RF channel in the DC detecting loop. The change in DC voltage.

The switch circuit 60 includes an input terminal connected to the RF input port 10, a control terminal connected to the detection port 80, and two output terminals respectively connected to the RF connector 30 and the built-in antenna 40, that is, the RF connector 30. The first output end of the connection, and the second output end connected to the built-in antenna 40, the switch circuit 60 is configured to switch the connection relationship between the input end and the two output terminals according to the DC voltage change acquired by the detection port 80. That is, the connection relationship between the RF input port 10 and the internal antenna 40 and the external antenna 20 is switched.

In the technical solution of the embodiment, the detecting circuit is connected in series with the RF connector and the external antenna, and is configured to detect whether the RF connector and the external antenna are normally connected based on the DC characteristics of the external antenna. The so-called DC-DC characteristics of an antenna refer to the characteristics that a radiator (ie, an antenna, or a feed point) can form a DC channel under the action of a DC voltage. The technical solution of the embodiment of the present invention utilizes this feature, and the detection circuit forms a DC detection loop with the RF connector and the external antenna, and the detection port is connected with the RF path, and the DC voltage variation therein can be detected. When the RF connector is connected to an external antenna, the DC voltage at the RF channel is grounded through an external antenna or connected to an additional voltage source, in a high or low state. When the RF connector is disconnected from the external antenna, the RF channel is suspended, in a high-impedance state, and the level state changes. The detection port is connected to the RF channel, that is, the RF channel is at an equipotential point, and the change of the DC voltage value in the RF channel is detected. In this embodiment, the switch circuit can be a single-pole double-throw switch circuit, and is a single-control switch circuit. The DC voltage detected at the detection port changes to a high level and a low level, which is equivalent to "1". " and "0" control signal, the control signal received by the control terminal can control the switch circuit to complete the switch.

Preferably, the first blocking unit 91 is disposed between the RF connector 30 and the switch circuit 60 for ensuring the direction of the DC signal and avoiding erroneous operation of the switch circuit.

The second blocking unit 92 and the third blocking unit 93 may also be disposed in the antenna switching circuit. The second blocking unit 92 is disposed between the RF input port 10 and the switch circuit 60, and the third blocking unit 93 is disposed in the built-in Between the antenna 40 and the switch circuit 60, the direction of the DC signal is ensured, and the erroneous operation of the detection circuit and the switch circuit can be avoided. The blocking unit can be a device such as a capacitor or a coupler that can function as a DC-connected AC.

Embodiment 2 FIG. 2 is a schematic structural diagram of another antenna switching circuit according to Embodiment 2 of the present invention. This embodiment is similar to the first embodiment except that the structure of the switching switch circuit is controlled.

The antenna switching circuit provided in this embodiment includes a radio frequency input port 10, a detecting port 80, an internal antenna 40, and a radio frequency connector 30. The switching circuit further includes a detecting circuit 50, an inverter 70, and a switch circuit 60. The detecting circuit 50 is configured to form a DC detecting loop when the RF connector 30 communicates with the external antenna 20 to form a RF channel, so that the detecting port 80 acquires a DC voltage change in the RF channel in the DC detecting loop; the input end of the inverter 70 The switch switch circuit 60 includes an input terminal connected to the RF input port 10, and two control terminals connected to the output port of the detection port 80 and the inverter 70, which are recorded as a first control terminal and a second control terminal. Also included is a first output connected to the RF connector 30 and a second output connected to the internal antenna 40. The switch circuit 60 is configured to switch the input according to the DC voltage change acquired at the output of the detection port 80 and the inverter 70. The connection relationship between the terminal and the first output terminal and the second output terminal.

In this embodiment, the detection circuit detects the change of the DC voltage in the RF channel in the first embodiment. The difference is that the switch circuit includes two control terminals, and the first control terminal is connected to the detection port, and the second control terminal is connected to the second control terminal. The output of the inverter. Since the input of the inverter is connected to the detection port, the level of the detection port can be inversely processed based on the inverting action of the inverter. Then, the levels input at the first control terminal and the second control terminal are opposite, and the two-level signals collectively control the switching action of the switching circuit.

In this embodiment, the switch circuit can be a single-pole double-throw switch circuit, and is a switch circuit of the dual control terminal, and the DC voltage detected at the detection port changes to a high level and a 氐 level change, which is equivalent to "1" "With the control signal of "0", the control signal received by the two control terminals is composed of "1, 0" or "0, 1", which can control the switching circuit to complete the switch.

This embodiment is similar to the first embodiment. Preferably, the first blocking unit 91, the second blocking unit 92 and/or the third blocking unit 93 may be further provided to isolate the DC signal.

The above embodiment uses a DC detection loop formed by a detection circuit, typically including a pull-up voltage and a voltage dividing unit. The voltage dividing unit is generally a resistor, and the relative position of the RF channel in the DC detection loop is not limited. If the voltage dividing unit is in the form of a pull-up resistor, the voltage value can be pulled to a high voltage when the RF channel is suspended, if In the form of a pull-down resistor, the voltage value can be pulled to a low voltage when the RF channel is left floating. The pull-up voltage may specifically be a pull-up voltage input port, or may be provided by a pull-up voltage of other internal components of the wireless communication device, and the voltage value of the pull-up voltage may be If the positive or negative value is considered, as long as a potential difference can be generated between the ground and the ground, the detection requirement of the detection port can be satisfied. The voltage value detected by the detection port is related to the pull-up voltage value, the setting position of the voltage dividing unit, and the resistance value of the voltage dividing unit. This can be set according to specific needs.

In order to avoid leakage or loss of RF signals, an isolation unit such as an inductor or a magnetic bead may be disposed between the RF channel and each device of the detection circuit. For example, the interconnection unit can be placed between the pull-up voltage and the RF channel to isolate the AC RF signal in the RF channel to avoid leakage or loss of the RF signal. An isolation unit is similarly disposed between the detection port and the RF channel to isolate the AC RF signal. The interfacing units can be shared or independently set.

The form of the detecting circuit can be various. The structure of the detecting circuit in the antenna switching circuit is further described by the preferred embodiment. In the following embodiments, the voltage dividing unit is used as a blocking unit, and the capacitor is used as a blocking unit. The unit, but those skilled in the art will appreciate that the voltage dividing unit, the blocking unit, and the blocking unit may also employ other devices having this function.

Embodiment 3

FIG. 3 is a schematic structural diagram of an antenna switching circuit according to Embodiment 3 of the present invention. This embodiment may provide a preferred detection circuit implementation manner based on the foregoing embodiments. For the sake of clarity, the switching circuit is not shown.

In this implementation, the RF channel between the RF connector and the RF input port is connected to the ground through the voltage dividing unit, and is used to form a DC detection loop when the RF connector is connected to the external antenna and the pull-up voltage connected to the external antenna. .

In this embodiment, as shown in FIG. 3, the external antenna D passes through the connector E and the RF connector.

F is connected; the number of the overlapping units is two, which is recorded as the first blocking inductance L1 and the second blocking inductance L2 in the embodiment; the pull-up voltage port Vcc is connected to the connector E through the first blocking inductor L1 and The RF channel between the external antenna D is provided to provide a pull-up voltage, and the RF channel between the RF connector F and the RF input port A is connected to the ground through the voltage dividing resistor R1 to form a DC detection loop; The two-interconnect inductor L2 is connected to the RF channel between the RF connector F and the RF input port A. In practical applications, the pull-up voltage port Vcc can be connected to the RF channel through an additional resistor R2 to obtain a suitable sense voltage value.

The technical solution of this embodiment divides the detection circuit into two parts, which are respectively disposed on the side of the RF connector F and the side of the external antenna D. When the connector E with the external antenna D is connected to the external RF connector F, since the DC resistance of the first blocking inductor L1 is small, the voltage at the RF channel is The value is pulled high by the voltage dividing resistor R1, and the detection port B detects a high level, and the system knows that the external antenna D is connected to the RF connector F. When the RF connector F is disconnected or not connected with the connector E with the external antenna D, the RF channel voltage value is pulled to the low level by the grounded voltage dividing resistor R1, and the detection port B detects the low level. The system can recognize that the connection is disconnected, which can trigger the switching switch circuit action, and can also be used to alarm the abnormal connection. Here, the external antenna D can be any form of active antenna, and can have a certain voltage difference from the pull-up voltage without having a DC to ground characteristic.

Embodiment 4

4 is a schematic structural diagram of an antenna switching circuit according to Embodiment 4 of the present invention. This embodiment may provide another preferred detection circuit implementation manner based on the foregoing embodiments. For the sake of clarity, the switch is not shown. Circuit.

In this embodiment, the detecting circuit includes a pull-up voltage and a voltage dividing unit; the pull-up voltage is connected to the RF channel between the RF connector and the RF input port through the voltage dividing unit, and forms a DC detecting loop with the external antenna.

In this embodiment, the number of the intervening inductances L may be one. Pull-up voltage through a voltage divider resistor

R3 and the isolation inductor L are connected to the RF channel between the RF connector F and the RF input port A, and form a DC detection loop with the external antenna D. The detection port B is connected to the RF channel between the RF connector F and the RF input port A through the gap inductance L. In the present embodiment, the external antenna D is an antenna having a DC-DC grounding characteristic and can be used as a low-voltage source in the DC detection circuit.

The working principle of this embodiment is as follows. When the external antenna D with DC grounding characteristics is connected to the RF connector F, the voltage value at the RF channel is small because the DC resistance of the blocking inductor L and the external antenna D is small. When pulled low, the detection port B detects a low level, and the system knows that the external antenna D is connected to the RF connector F. When the connection between the RF connector F and the external antenna D is disconnected or the external RF connector F is not connected to the external antenna D, the RF channel is in a floating high impedance state, and the voltage at the RF channel is pulled up to the high by the voltage dividing resistor R. Level, at this time, detecting port B detects a high level, which can be used to trigger the switching circuit operation, and can also be used to disconnect the external antenna D of the alarm.

Embodiment 5

FIG. 5 is a schematic structural diagram of an antenna switching circuit according to Embodiment 5 of the present invention. This embodiment may provide a preferred inverter and switch circuit implementation based on the foregoing embodiment. The mode and FIG. 5 are specifically described by taking the structure of the detecting circuit of the fourth embodiment as an example.

The input end of the inverter 70 is connected to the detection port B, and the level of the detection port B is inverted, and is output from the output terminal. The switch circuit 60 is disposed between the RF input port A and the RF connector F and the built-in antenna G. The two control ends of the switch circuit 60 are respectively connected to the output terminals of the detection port B and the inverter 70, and are used for switching the connection relationship between the RF input port A and the RF connector F and the built-in antenna G according to the switching control signals input by the two control terminals. The switch 62 includes a first input connected to the detection port B and a second input connected to the output of the inverter 70 for respectively receiving an input signal to form a switching control signal . Each end of the switch circuit 60 is connected to the RF input port A, the RF connector F and the built-in antenna G through the DC blocking capacitors Cl, C2 and C3, respectively, to prevent the switching circuit 60 from malfunctioning. Specifically, the DC blocking capacitor C2 prevents the pull-up voltage Vcc, the voltage dividing resistor R3, the blocking inductance L, and the switching circuit from forming a DC link, thereby preventing the detecting circuit from detecting an error when the external antenna D is connected. The DC blocking capacitor C3 prevents the pull-up voltage Vcc, the resistor R4, the inverter, the diverter switch circuit, and the built-in antenna G from forming a loop to prevent the switch circuit from functioning properly. DC blocking capacitor C1 prevents the pull-up voltage VCC, resistor R4, switching circuit and DC blocking capacitor C1 from forming a DC loop, which prevents the switching circuit from working properly.

In this embodiment, the output terminal of the inverter 70 can be connected in series with a resistor R4 and then connected to the pull-up voltage port Vcc, so that the output terminal of the inverter 70 can output a level signal opposite to the input according to the level signal of the input terminal, The changeover switch circuit 60 is controlled.

The switch circuit is further provided with a ground terminal according to actual design requirements. The signals input by the first control terminal and the second control terminal are "0, 1" and "1, 0" by the action of the inverter, and are identified. Whether the external antenna is disconnected, so as to timely decide whether to switch to the internal antenna or the external antenna to ensure normal communication.

The working principle of the antenna switching circuit of this embodiment is as follows:

As shown in Figure 6, when the external antenna D with DC characteristics is connected to the RF connector F,

The DC detection circuit (pull-up voltage Vcc, voltage-dividing resistor R3, blocking inductor L, RF connector F, and external antenna D) shown by the thick medium line in 6 will be formed due to the DC resistance of the isolated inductor L and The DC resistance of the external antenna D is small, the voltage at the RF channel is pulled to a low level, and the detection port B detects a low level, that is, "0", combined with the high level generated by the output of the inverter 70, that is, The "1" signal is used to control the switching circuit 60, and the RF input port A is connected to the RF connector F. The path (shown by the thick dashed line in Fig. 6) is turned on, and the external antenna D operates normally.

As shown in FIG. 7, when the connection between the RF connector F and the external antenna D is disconnected or the RF connector F is not connected to the external antenna D, the DC detection loop is broken or cannot be formed, and the voltage at the RF channel is equal to the pull-up voltage. The voltage of the port Vcc is detected, and the voltage of the detection port B is pulled up to a high level. At this time, the inverter 70 is turned on, and the input terminal voltage of the inverter 70 is equal to the high level at the detection port B, and the pull-up voltage Vcc, A direct current loop is formed between the inverter 70 and the ground. At this moment, the input signal of the second control terminal of the switch circuit 60 is "0", and the input signal of the first control terminal is "1". The high level of the detection port B is combined with the low level signal generated by the output of the inverter 70 to control the switching switch circuit 60, and the RF path of the RF input port A to the internal antenna G is turned on, and the built-in antenna G operates normally. At this time, the high level of the detection port B is detected, and it can also be used for disconnecting the external antenna D of the alarm.

In addition, if the switch circuit is a single-ended device, such as a single-control device with a single-control terminal, the inverter can be saved by directly connecting the detection port B to the control terminal of the single-ended control switch circuit.

Embodiment 6

FIG. 8 is a schematic structural diagram of an antenna switching circuit according to Embodiment 6 of the present invention. This embodiment may provide a preferred implementation manner of an inverter and a switching circuit based on the foregoing embodiment, and FIG. 8 is specifically implemented. The detection circuit structure of the third example is taken as an example for explanation.

In this embodiment, an inverter 70 and a switch circuit 60 are included. The input end of the inverter 70 is connected to the detection port B. The switch circuit 60 is disposed between the RF input port A and the RF connector F and the built-in antenna G, and is used for switching the RF according to the switching control signals input by the two control terminals. The connection relationship between the input port A and the RF connector F and the built-in antenna G. The switch circuit 60 includes a first input coupled to the sense port B and a second input coupled to the output of the inverter 70 for receiving input signals to form a switching control signal, respectively. .

In this embodiment, the switching circuit is similar to the working principle of the fifth embodiment. The signals input by the first control terminal and the second control terminal are in the states of "0, 1" and "1, 0", and the switching circuit can be different according to different conditions. The status identifies whether the external antenna is disconnected from the RF connector, so as to determine whether to switch to the internal antenna or the external antenna in time to ensure the normal operation of the RF signal and the antenna.

For the switch control circuit of the single control terminal provided in the implementation of the first, it can be set without The inverter directly connects the detection port to the control end of the single-ended control switch circuit, and the other connection structures are similar to those of the fourth and fifth embodiments.

The technical solution of the embodiments of the present invention provides a mechanism for automatically monitoring the connection state of the cable and the connector of the RF connector and the external antenna or the antenna, and automatically switches the RF channel to the internal antenna, and preferably also alarms. The RF connector is loose or loose. Applicable RF connectors include, but are not limited to, RF coaxial SMA (Small A Type) connectors, RF switches (bend RF connectors), RF switches (RF Switch) - Straight RF connections , "Mount" coaxial connectors, etc.

The embodiment of the invention further provides a wireless terminal device, including a radio frequency input port, a detection port, a radio frequency connector and an internal antenna, and a device required by other wireless terminal devices, and the radio frequency connector can be connected to an external antenna, the wireless terminal The apparatus further includes a detection circuit and a diverter switch circuit, or further includes a detection circuit, an inverter, and a diverter switch circuit, that is, specifically including an antenna switching circuit provided by any of the embodiments of the present invention. The wireless terminal device typically can be a cell phone, a power gateway, or the like.

The technical solution of the embodiment of the invention has many advantages: converting the connection state of the external antenna into a DC level output, which facilitates software detection or control of other circuits; and the connection state detection result of the external antenna is widely used, for example: The terminal device can intelligently switch between the internal and external antennas according to whether an external antenna is connected. When the external antenna is detached or damaged, the terminal can switch to the internal antenna without causing the communication to terminate. Or on a mobile or vibrating terminal device, when the RF connector is easy to loose or fall off, the communication quality is seriously degraded or the communication cannot be performed normally. By detecting the connection state of the external antenna, the problem can be found in time for maintenance, and avoiding In the case of antenna connection (ie, port mismatch), for example, the hardware damage caused by the high-power transmission of the RF transceiver is turned on; the technical solution is easy to implement, the detection is reliable and stable, and the circuit is simple and the cost is low.

It should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present invention. range.

Claims

Claim

An antenna switching circuit, comprising: a radio frequency input port, a detection port, an internal antenna, and a radio frequency connector, the switching circuit further comprising:

The antenna switching circuit according to claim 1, wherein the switching switch circuit is a single-pole double-throw switch circuit.

The antenna switching circuit according to claim 1 or 2, further comprising: a first blocking unit disposed between the RF connector and the switching circuit.

The antenna switching circuit according to any one of claims 1 to 3, further comprising a second blocking unit and a third blocking unit, wherein the second blocking unit is disposed at the radio frequency input port and the Between the switch circuits, the third blocker unit is disposed between the internal antenna and the switch circuit.

The antenna switching circuit according to any one of claims 1 to 3, wherein: the radio frequency channel between the radio frequency connector and the radio frequency input port is connected to the ground through a voltage dividing unit, and is used for the radio frequency connection. When the device is connected to the external antenna, the pull-up voltage connected to the external antenna forms the DC detection loop.

The antenna switching circuit according to any one of claims 1 to 3, wherein: the detecting circuit comprises a pull-up voltage and a voltage dividing unit;

The pull-up voltage is connected to the RF channel between the RF connector and the RF input port through the voltage dividing unit, and forms a DC detection loop with the external antenna.

An antenna switching circuit, comprising: a radio frequency input port, a detection port, an internal antenna, and an RF connector, the switching circuit further comprising:

a detecting circuit, configured to form a DC detecting loop when the RF connector is connected to the external antenna to form an RF channel, so that the detecting port obtains a straight line in the RF channel in the DC detecting loop Current voltage change

An inverter, an input end of the inverter is connected to the detection port;

a switch circuit comprising: an input connected to the RF input port, a first control terminal connected to the detection port, a second control terminal connected to the inverter output terminal, and the RF connector a first output end, and a second output end connected to the internal antenna, the switch circuit is configured to switch the input end according to a DC voltage change acquired by the detection port and the inverter output end The connection relationship with the two outputs.

8. The antenna switching circuit according to claim 7, further comprising: a first blocking unit disposed between the RF connector and the switching circuit.

The antenna switching circuit according to claim 7 or 8, further comprising a second blocking unit and a third blocking unit, wherein the second blocking unit is disposed at the RF input port and the switch Between the circuits, the third blocking unit is disposed between the internal antenna and the switching circuit.

The antenna switching circuit according to any one of claims 7-9, wherein: the RF channel between the RF connector and the RF input port is connected to the ground through a voltage dividing unit, and is used for the RF connection. When the device is connected to the external antenna, the pull-up voltage connected to the external antenna forms the DC detection loop.

The antenna switching circuit according to any one of claims 7-9, wherein: the detecting circuit comprises a pull-up voltage and a voltage dividing unit;

A wireless terminal device, comprising: a radio frequency input port, a detection port, a radio frequency connector, and a built-in antenna, the wireless terminal device further comprising:

13. The wireless terminal device according to claim 12, wherein: the switching switch circuit is a single-pole double-throw switch circuit.

The wireless terminal device according to claim 12 or 13, further comprising:

A first blocking unit is disposed between the RF connector and the switch circuit.

The wireless terminal device according to any one of claims 12-14, further comprising a second blocking unit and a third blocking unit, wherein the second blocking unit is disposed at the radio frequency input port and the Between the switch circuits, the third blocker unit is disposed between the internal antenna and the switch circuit.

The wireless terminal device according to any one of claims 12-14, wherein: the radio frequency channel between the radio frequency connector and the radio frequency input port is connected to the ground through the voltage dividing unit, and is used for the radio frequency connection. When the device is connected to the external antenna, the pull-up voltage connected to the external antenna forms the DC detection loop.

The wireless terminal device according to any one of claims 12-14, wherein: said detecting circuit comprises a pull-up voltage and a voltage dividing unit;

The wireless terminal device according to any one of claims 12-14, wherein: the wireless terminal device is a power gateway.

An inverter, an input end of the inverter is connected to the detection port;

20. The wireless terminal device of claim 21, further comprising: a first blocking unit disposed between the RF connector and the switch circuit.

The wireless terminal device according to claim 19 or 20, further comprising a second blocking unit and a third blocking unit, wherein the second blocking unit is disposed at the radio frequency input port and the switch Between the circuits, the third blocking unit is disposed between the internal antenna and the switching circuit.

The wireless terminal device according to any one of claims 19 to 21, wherein: the radio frequency channel between the radio frequency connector and the radio frequency input port is connected to the ground through the voltage dividing unit, and is used for the radio frequency connection. When the device is connected to the external antenna, the pull-up voltage connected to the external antenna forms the DC detection loop.

The wireless terminal device according to any one of claims 19 to 21, wherein: the detecting circuit comprises a pull-up voltage and a voltage dividing unit;

The wireless terminal device according to any one of claims 19-21, wherein: the wireless terminal device is a power gateway.