CN114421421A - Protection control circuit, navigation system, communication terminal and control method - Google Patents

Abstract

The invention discloses a protection control circuit, a navigation system, a communication terminal and a control method. By setting the selection control circuit, when the signal at the enable signal terminal and the signal at the load connection terminal are both at the second level, the selection control circuit can output the conduction The control signal is used to control the conduction of the switch control unit, so as to make conduction between the output terminal of the unit to be protected and the load connection terminal, so that the signal output by the to-be-protected unit can be input to the load through the load connection terminal. When at least one of the signal at the enable signal end and the signal at the load connection end is at the first level, the selection control circuit may output a disconnection control signal to control the switch control unit to be disconnected, so as to control the output end of the unit to be protected and the The load connection terminals are disconnected, so as to effectively avoid the problem that the output current of the unit to be protected is too large and burns out due to the short circuit of the load.

Description

Protection control circuit, navigation system, communication terminal and control method

technical field

The invention relates to the technical field of circuit protection, in particular to a protection control circuit, a navigation system, a communication terminal and a control method.

Background technique

With the rapid development of science and technology, more and more components are set in the communication terminal. Among these components, there are units that provide signals and units that receive signals. If the unit that receives the signal is short-circuited, the unit that provides the signal will burn out.

SUMMARY OF THE INVENTION

In a first aspect, an embodiment of the present invention provides a protection control circuit, including:

The selection control circuit is configured to output a signal through the selection output terminal according to the signal of the load connection terminal and the signal of the enable signal terminal of the unit to be protected;

The switch control unit is configured to be connected to the selection output terminal, and according to the signal output from the selection output terminal, control the on and off between the output terminal of the unit to be protected and the load connection terminal.

The beneficial effects of the present invention are as follows: by setting a switch control unit between the output end of the unit to be protected and the load connection end, and by setting a selection control circuit, the signal at the enable signal end and the signal at the load connection end are the first At two levels, the selection control circuit can output a conduction control signal to control the conduction of the switch control unit, so that the output terminal of the control unit to be protected and the load connection terminal are connected, so that the output signal of the unit to be protected can be Input the load through the load connection terminal. When at least one of the signal at the enable signal end and the signal at the load connection end is at the first level, the selection control circuit may output a disconnection control signal to control the switch control unit to be disconnected, so as to control the output end of the unit to be protected and the The load connection terminals are disconnected, so that the unit to be protected and the load can be disconnected, so as to effectively avoid the problem that the output current of the unit to be protected is too large and burn out due to the short circuit of the load.

In a second aspect, an embodiment of the present invention provides a navigation system, including: an active antenna, a power supply unit, and the above-mentioned protection control circuit; the unit to be protected is the power supply unit, and the load connection end is connected to the active antenna .

The beneficial effects of the present invention are as follows: when the protection control circuit in the embodiment of the present invention is applied to a navigation system, a switch control unit is arranged between the output end of the unit to be protected and the load connection end that needs to be protected, and the selection is made by setting The control circuit, when the signal of the enable signal terminal and the signal of the load connection terminal are both at the second level, the selection control circuit can output a conduction control signal to control the conduction of the switch control unit, so as to control the output terminal of the unit to be protected and the load The connection terminals are connected, so that the signal output by the unit to be protected can be input to the load through the load connection terminal. When at least one of the signal at the enable signal end and the signal at the load connection end is at the first level, the selection control circuit may output a disconnection control signal to control the switch control unit to be disconnected, so as to control the output end of the unit to be protected and the The load connection terminals are disconnected, so that the unit to be protected and the load can be disconnected, so as to effectively avoid the problem that the output current of the unit to be protected is too large and burn out due to the short circuit of the load.

In a third aspect, an embodiment of the present invention provides a communication terminal, including: the above-mentioned navigation system.

The beneficial effects of the present invention are as follows: when the protection control circuit in the embodiment of the present invention is applied to a communication terminal, a switch control unit is arranged between the output end of the unit to be protected and the load connection end that needs to be protected, and the selection is made by setting The control circuit, when the signal of the enable signal terminal and the signal of the load connection terminal are both at the second level, the selection control circuit can output a conduction control signal to control the conduction of the switch control unit, so as to control the output terminal of the unit to be protected and the load The connection terminals are connected, so that the signal output by the unit to be protected can be input to the load through the load connection terminal. When at least one of the signal at the enable signal end and the signal at the load connection end is at the first level, the selection control circuit may output a disconnection control signal to control the switch control unit to be disconnected, so as to control the output end of the unit to be protected and the The load connection terminals are disconnected, so that the unit to be protected and the load can be disconnected, so as to effectively avoid the problem that the output current of the unit to be protected is too large and burn out due to the short circuit of the load.

In a fourth aspect, an embodiment of the present invention provides a control method for a protection control circuit, including:

When at least one of the signal at the enable signal terminal and the signal at the load connection terminal is at a first level, the selection control circuit outputs a signal with a first level through the selection output terminal; the switch controls The unit controls the disconnection between the output end of the unit to be protected and the load connection end according to the signal with the first level output by the selection output end;

When the signal at the enable signal terminal and the signal at the load connection terminal are both at the second level, the selection control circuit outputs a signal with the second level through the selection output terminal; the switch control unit according to the The signal with the second level output from the selection output terminal controls the conduction between the output terminal of the unit to be protected and the load connection terminal.

The beneficial effects of the present invention are as follows: by setting a switch control unit between the output end of the unit to be protected and the load connection end, and by setting a selection control circuit, the signal at the enable signal end and the signal at the load connection end are the first At two levels, the selection control circuit can output a conduction control signal to control the conduction of the switch control unit, so that the output terminal of the control unit to be protected and the load connection terminal are connected, so that the output signal of the unit to be protected can be Input the load through the load connection terminal. When at least one of the signal at the enable signal end and the signal at the load connection end is at the first level, the selection control circuit may output a disconnection control signal to control the switch control unit to be disconnected, so as to control the output end of the unit to be protected and the The load connection terminals are disconnected, so that the unit to be protected and the load can be disconnected, so as to effectively avoid the problem that the output current of the unit to be protected is too large and burn out due to the short circuit of the load.

Description of drawings

1a is a schematic diagram of some structures of a navigation system in an embodiment of the present invention;

FIG. 1b is a schematic structural diagram of a communication terminal in an embodiment of the present invention;

2 is another schematic structural diagram of a navigation system in an embodiment of the present invention;

3 is another schematic structural diagram of a navigation system in an embodiment of the present invention;

FIG. 4 is another schematic structural diagram of the navigation system in the embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, embodiments of the present invention. Also, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict. Based on the described embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

Unless otherwise defined, technical or scientific terms used in the present invention should have the ordinary meaning as understood by one of ordinary skill in the art to which the present invention belongs. The terms "first," "second," and similar terms used herein do not denote any order, quantity, or importance, but are merely used to distinguish different components. "Comprises" or "comprising" and similar words mean that the elements or things appearing before the word encompass the elements or things recited after the word and their equivalents, but do not exclude other elements or things. Words like "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

It should be noted that the dimensions and shapes of the figures in the accompanying drawings do not reflect the actual scale, and are only intended to illustrate the content of the present invention. And the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout.

Generally, in a navigation system, for example, a Global Navigation Satellite System (Global Navigation Satellite System, GNSS), there are mainly two types of antennas used in the GNSS receiver, namely passive antennas and active antennas. Among them, passive antennas, that is, ordinary ceramic antennas or built-in planar inverted-F antennas (PIFA), have no amplifiers on the antennas and can work without power supply. In some special products, such as car navigation and professional navigation equipment, it is not recommended to use passive antennas, but active antennas.

An active antenna refers to an antenna with a low noise amplifier (external Low Noise Amplifier, eLNA), which requires power supply to work, and the power supply is completed by a special power supply unit. Compared with passive antennas, active antennas are larger in size, and the eLNA is placed close to the antenna, which can greatly reduce the noise figure of the system, thereby obtaining better satellite signal reception performance, and can be applied to higher positioning performance requirements. PAD, three-proof machine, car navigator, mobile phone and other products.

Usually, the passive antenna can be connected to the GNSS chip through the antenna shrapnel (sometimes by means of coaxial wire snapping). Since the antenna does not require power, even a short circuit of the antenna will not have any destructive effect on the entire RF path.

1a, the active antenna 14 will have a coaxial line 15 leading out, and the main board 10 (for example, the main board 10 of the mobile phone or the main board 10 provided with the GNSS chip 11 in the navigator) is designed with a coaxial line socket 13. 15 is fastened to the coaxial socket 13 , and the GPS radio frequency signal and the DC current of the power supply unit 12 on the main board 10 can enter the active antenna 14 through the coaxial socket 13 and the coaxial cable 15 . Since there is a power supply unit 12 for supplying power to the antenna on the main board 10, if there is a short circuit inside the active antenna 14 or where the coaxial cable 15 and the coaxial cable socket 13 are buckled (that is, the transmission path of the radio frequency signal is short-circuited to the ground), the power supply Cell 12 will burn out due to excessive current flow.

In this embodiment of the present invention, the navigation system may include an active antenna 14 , a power supply unit 12 and a protection control circuit 100 . Wherein, the unit to be protected connected to the protection control circuit 100 can be set as the power supply unit 12 on the main board 10 having the GNSS chip 11, and the load connection end can be set as the coaxial socket 13, that is, the load connection end can be connected with the active antenna 14 .

Exemplarily, the navigation system in the embodiment of the present invention may be applied to a communication terminal. Exemplarily, the communication terminal may be a product such as a PAD, a three-proof machine, a car navigator, a mobile phone, and a smart TV.

FIG. 1 b shows a schematic structural diagram of the communication terminal 01 .

The embodiment will be specifically described below by taking the communication terminal 01 as an example. It should be understood that the communication terminal 01 shown in Figure 1b is only an example, and that the communication terminal 01 may have more or fewer components than those shown in Figure 1b, two or more components may be combined, or Different component configurations are possible. The various components shown in the figures may be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and/or application specific integrated circuits.

FIG. 1b exemplarily shows a block diagram of the hardware configuration of the communication terminal 01 according to the exemplary embodiment. As shown in FIG. 1b, the communication terminal 01 includes: a radio frequency (RF) circuit 0110, a memory 120, a display unit 130, a camera 140, a sensor 150, an audio circuit 160, and a Wireless Fidelity (Wi-Fi) module 170 , a processor 180 , a Bluetooth module 181 , an input unit 182 , a power supply 190 and other components.

The RF circuit 0110 can be used for receiving and sending signals during sending and receiving information or during a call, can receive downlink data from the base station and then hand it over to the processor 180 for processing; and can send uplink data to the base station. Generally, the RF circuit includes but is not limited to active antenna, protection control circuit 100, power supply unit 12, GNSS chip 11, at least one amplifier, transceiver, coupler, low noise amplifier, duplexer and other devices. For example, the processor 180 may input a signal to the enable signal terminal in response to the operation to control the operation of the GNSS chip 11 and the power supply unit 12 in the navigation system 290 .

Memory 120 may be used to store software programs and data. The processor 180 executes various functions of the communication terminal 01 and data processing by executing software programs or data stored in the memory 120 . Memory 120 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other volatile solid state storage device. The memory 120 stores an operating system that enables the communication terminal 01 to operate. In this application, the memory 120 may store an operating system and various application programs, and may also store codes for executing the methods described in the embodiments of this application.

The display unit 130 can be used to receive input digital or character information, and generate signal input related to user settings and function control of the communication terminal 01. Touch operations on or near it, such as clicking a button, dragging a scroll box, etc.

The display unit 130 may also be used to display information input by the user or information provided to the user and a graphical user interface (GUI) of various menus of the terminal 100 . Specifically, the display unit 130 may include a display screen 132 disposed on the front of the communication terminal 01 . The display screen 132 may be configured in the form of a liquid crystal display, a light emitting diode display, or the like. The display unit 130 may be used to display various graphical user interfaces described in this application. The touch screen 131 may cover the display screen 132, or the touch screen 131 and the display screen 132 may be integrated to realize the input and output functions of the communication terminal 01, which may be referred to as touch screen after integration. In this application, the display unit 130 can display application programs and corresponding operation steps.

Camera 140 may be used to capture still images or video. The object is projected through the lens to generate an optical image onto the photosensitive element. The photosensitive element may be a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) phototransistor. The photosensitive element converts the optical signal into an electrical signal, and then transmits the electrical signal to the processor 180 for conversion into a digital image signal.

The communication terminal 01 may further include at least one sensor 150 , such as an acceleration sensor 151 , a distance sensor 152 , a fingerprint sensor 153 , and a temperature sensor 154 . The communication terminal 01 may also be configured with other sensors such as a gyroscope, a barometer, a hygrometer, a thermometer, an infrared sensor, a light sensor, and a motion sensor.

The audio circuit 160 , the speaker 161 , and the microphone 162 may provide an audio interface between the user and the communication terminal 01 . The audio circuit 160 can transmit the electrical signal converted from the received audio data to the speaker 161, and the speaker 161 converts it into a sound signal and outputs it. The communication terminal 01 can also be configured with a volume button for adjusting the volume of the sound signal. On the other hand, the microphone 162 converts the collected sound signal into an electrical signal, which is received by the audio circuit 160 and converted into audio data, and then outputs the audio data to the RF circuit 0110 for transmission to, for example, another terminal, or outputs the audio data to memory 120 for further processing. In this application, the microphone 162 can acquire the user's voice.

Wi-Fi is a short-distance wireless transmission technology. The communication terminal 01 can help users to send and receive emails, browse web pages, and access streaming media through the Wi-Fi module 170, which provides users with wireless broadband Internet access.

The processor 180 is the control center of the communication terminal 01, uses various interfaces and lines to connect various parts of the entire terminal, and executes the communication terminal by running or executing the software programs stored in the memory 120 and calling the data stored in the memory 120. 01's various functions and processing data. In some embodiments, the processor 180 may include one or more processing units; the processor 180 may also integrate an application processor and a baseband processor, wherein the application processor mainly processes the operating system, user interface and application programs, etc., and the baseband The processor mainly handles wireless communication. It can be understood that, the above-mentioned baseband processor may not be integrated into the processor 180 . In this application, the processor 180 may run an operating system, an application program, a user interface display and a touch response, as well as the processing methods described in the embodiments of this application.

The bluetooth module 181 is used to exchange information with other bluetooth devices having bluetooth modules through the bluetooth protocol. For example, the communication terminal 01 can establish a Bluetooth connection with a wearable electronic device (such as a smart watch) that also has a Bluetooth module through the Bluetooth module 181, so as to perform data interaction.

The input unit 182 is used for receiving user instructions, wherein the input unit 182 may be a touch screen, a microphone or a remote control receiving device. Exemplarily, for example, the remote control is an infrared remote control, and the remote control receiving device is an infrared receiver; for example, the remote control is a Bluetooth remote control, and the remote control receiving device is a Bluetooth receiving device; for example, the remote control is a remote control transmitted via a wireless network, The remote control receiver is a receiver capable of receiving wireless network transmissions. In addition, the processor 180 is coupled with the display unit 130 and the input unit 182 .

The communication terminal 01 also includes a power source 190 (eg, a battery) for powering the various components. The power supply can be logically connected to the processor 180 through a power management system, so that functions such as managing charging, discharging, and power consumption are implemented through the power management system. The communication terminal 01 can also be configured with a power button, which is used to power on and off the terminal, and lock the screen and other functions.

In this embodiment of the present invention, the unit to be protected may also be the power supply unit 12 on the motherboard 10 where the System on Chip (SOC) is located, and the load connection end may be configured as an interface such as GPIO. Of course, the to-be-protected unit may also be the power supply unit 12 on the motherboard 10 where other types of chips are located, which may be specifically determined according to actual application requirements, which is not limited herein.

In the embodiment of the present invention, as shown in FIG. 2 , the enable signal terminal GPS-EN is connected to the GNSS chip 11 and the power supply unit 12 respectively. When the enable signal terminal GPS-EN is at the first level (eg, low level), the GNSS chip 11 and the power supply unit 12 can be controlled to not work. When the enable signal terminal GPS-EN is at the second level (for example, a high level), the GNSS chip 11 and the power supply unit 12 can be controlled to start working, so that the power supply unit 12 outputs a DC current to the active antenna, and the GNSS chip 11 sends a direct current to the active antenna. The active antenna outputs GPS RF signals.

In the following, the unit to be protected can be set as the power supply unit 12 on the main board 10 having the GNSS chip 11 , and the load connection end is the coaxial socket 13 . For example, the first level is a low level and the second level is a high level. Of course, the first level may also be a high level, and the second level may also be a low level, which is not limited herein.

In this embodiment of the present invention, as shown in FIG. 2 , the protection control circuit 100 may include: a selection control circuit 110 and a switch control unit 120 . Wherein, the selection control circuit 110 can output the signal through the selection output terminal according to the signal of the enable signal terminal GPS-EN and the signal of the load connection terminal. The switch control unit 120 can be connected to the selection output terminal, and according to the signal output by the selection output terminal, controls the connection and disconnection between the output terminal of the unit to be protected and the load connection terminal. The unit to be protected may be connected to the load through the load connection terminal, and the unit to be protected may output a signal to the load through the load connection terminal.

In the above protection control circuit provided by the embodiment of the present invention, a switch control unit is arranged between the output end of the unit to be protected and the load connection end to be protected, and by setting a selection control circuit, the signal at the enable signal end and the load connection end are connected. When the signals are all at the second level, the selection control circuit can output a conduction control signal to control the switch control unit to conduct, so as to make the output terminal of the unit to be protected and the load connection terminal to conduct conduction, so that the unit to be protected can be turned on. The output signal can be input to the load through the load connection terminal. When at least one of the signal at the enable signal end and the signal at the load connection end is at the first level, the selection control circuit may output a disconnection control signal to control the switch control unit to be disconnected, so as to control the output end of the unit to be protected and the The load connection terminals are disconnected, so that the unit to be protected and the load can be disconnected, so as to effectively avoid the problem that the output current of the unit to be protected is too large and burn out due to the short circuit of the load.

In the embodiment of the present invention, as shown in FIG. 2 , the selection control circuit 110 is connected to the enable signal terminal GPS-EN, the load connection terminal and the switch control unit 120 . In this way, the selection control circuit 110 can input a control signal to the switch control unit 120 according to the signal of the enable signal terminal GPS-EN and the signal of the load connection terminal. The switch control unit 120 can also be connected to the power supply unit 12 and the coaxial socket 13 . In this way, the switch control unit 120 can control the conduction and disconnection between the power supply unit 12 and the coaxial socket 13 under the control of the selection control circuit 110 . For example, as long as one of the signal of the enable signal terminal GPS-EN and the signal of the load connection terminal is low level, the selection control circuit 110 will output a low level signal to control the switch control unit 120 to switch the power supply unit 12 and the coaxial socket 13 are disconnected. For example, when there is a short circuit inside the active antenna or at the joint of the coaxial cable, because it is a short circuit to ground, the signal at the coaxial cable socket 13 is at a low level, and the power supply unit 12 and the coaxial cable socket 13 are disconnected. , so that the problem of burnout of the power supply unit 12 due to excessive output current can be effectively avoided. For example, when the signal of the enable signal terminal GPS-EN and the signal of the load connection terminal are both at a high level, it means that the power supply unit 12 and the active antenna are both working normally, that is, there is no short circuit inside the active antenna or at the joint of the coaxial cable. Then the selection control circuit 110 will output a high level signal to control the switch control unit 120 to conduct the power supply unit 12 and the coaxial socket 13, so that the power supply unit 12 can supply power to the active antenna normally.

In this embodiment of the present invention, as shown in FIG. 3 , the selection control circuit 110 may include an AND gate; wherein, the first input end of the AND gate is electrically connected to the enable signal end GPS-EN, and the second input end of the AND gate is electrically connected to The load connection terminal (for example, the coaxial socket 13 ) is electrically connected, and the output terminal of the AND gate is used as the selection output terminal. Exemplarily, when both the first input terminal and the second input terminal of the AND gate input a high-level signal, the output terminal of the AND gate outputs a high-level signal. When only one of the first input terminal and the second input terminal of the AND gate inputs a low-level signal, its output terminal will output a low-level signal.

In this embodiment of the present invention, as shown in FIG. 3 , the AND gate may include: a first resistor R1, a first diode AD1 and a second diode AD2; wherein the first end of the first resistor R1 is connected to the reference power supply The voltage terminal VCC is connected, and the second terminal of the first resistor R1 is connected to the anode of the first diode AD1 and the anode of the second diode AD2 respectively, as the output terminal of the AND gate; the cathode of the first diode AD1 is used as the output terminal of the AND gate. The first input terminal; the cathode of the second diode AD2 is used as the second input terminal.

Exemplarily, the resistance value of the first resistor R1 may range from 1 kΩ to 10 kΩ. For example, the resistance value of the first resistor R1 can be 1kΩ, the resistance value of the first resistor R1 can also be 2kΩ, the resistance value of the first resistor R1 can also be 3kΩ, the resistance value of the first resistor R1 can also be 5kΩ, and the resistance value of the first resistor R1 can also be 5kΩ. The resistance value of the first resistor R1 may also be 8kΩ, and the resistance value of the first resistor R1 may also be 10kΩ, which is not limited herein.

Exemplarily, the voltage of the reference power supply voltage terminal VCC is a positive voltage. For example, the voltage of the reference power voltage terminal VCC may be 4V. Of course, in practical applications, the voltage of the reference power supply voltage terminal VCC can be determined according to the requirements of practical applications, which is not limited here.

In the embodiment of the present invention, the reference power supply voltage terminal VCC is also connected to the power supply unit 12, and the power supply unit 12 receives the input power supply voltage of the reference power supply voltage terminal VCC, and can convert the power supply voltage to be converted into the power supply voltage required by the active antenna. voltage. For example, the voltage input by the reference power supply voltage terminal VCC is 4V, and the power supply unit 12 receives the voltage of 4V, converts the voltage of 4V into 1.8V, and provides it to the active antenna.

In this embodiment of the present invention, as shown in FIG. 3 , the switch control unit 120 may include a first switch K1; wherein the control end of the first switch K1 is connected to the selection output end, and the first end of the first switch K1 is connected to the unit to be protected The output end of the first switch K1 is connected to the load connection end, and the second end of the first switch K1 is connected. The first switch K1 is in a conducting state when the signal whose output terminal is at a high level is selected. When the first switch K1 selects a signal whose output terminal is at a low level, it is in an off state.

Exemplarily, the first switch K1 may include a triode. The base of the triode serves as the control end of the first switch K1, the collector of the triode serves as the first end of the first switch K1, and the emitter of the triode serves as the second end of the first switch K1.

Exemplarily, the first switch K1 may also include a metal-oxide-semiconductor field-effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET). The gate of the MOSFET is used as the control terminal of the first switch K1, the source of the MOSFET is used as the first terminal of the first switch K1, and the drain of the MOSFET is used as the second terminal of the first switch K1.

In this embodiment of the present invention, as shown in FIG. 4 , the protection control circuit 100 may further include: a first protection inductor L1 ; wherein the switch control unit 120 is connected to the load connection end through the first protection inductor L1 . Exemplarily, the second end of the first switch K1 is electrically connected to the coaxial socket 13 through the first protection inductor L1. In this way, when the switch control unit 120 is turned on, the GPS radio frequency signal can be prevented from entering the power supply unit 12 and the radio frequency performance is deteriorated.

Exemplarily, the inductance of the first protection inductor L1 may be set to 68nH. Of course, in practical applications, the inductance of the first protection inductor L1 can be determined according to the requirements of practical applications, which is not limited here.

In the embodiment of the present invention, as shown in FIG. 4 , the protection control circuit 100 further includes: a second protection inductor L2; wherein, the selection control circuit 110 is connected to the load connection end through the second protection inductor L2. Exemplarily, the cathode of the second diode AD2 is electrically connected to the coaxial socket 13 through the second protection inductor L2. In this way, the GPS radio frequency signal can be prevented from entering the selection control circuit 110, resulting in misjudgment of the signal at the load connection end.

Exemplarily, the inductance of the second protection inductor L2 may be set to 68nH. Of course, in practical applications, the inductance of the second protection inductor L2 can be determined according to the requirements of practical applications, which is not limited here.

In the embodiment of the present invention, as shown in FIG. 4 , the navigation system further includes a capacitor C0 and a surface acoustic filter (Saw) 16 . The GNSS chip is connected to the coaxial socket 13 through the Saw16 and the capacitor C0 in sequence. Exemplarily, the capacitance value of the capacitor C0 is 33pF. Of course, the capacitance value of the capacitor C0 can also be determined according to the requirements of practical applications, which is not limited here.

The structure of the protection control circuit 100 shown in FIG. 4 will be described below.

Exemplarily, when at least one of the signal at the enable signal terminal and the signal at the load connection terminal is at the first level, the selection control circuit outputs a disconnection control signal through the selection output terminal; the switch control unit outputs a disconnection control signal according to the selection output terminal. The control signal controls the disconnection between the output terminal of the unit to be protected and the load connection terminal. For example, when at least one of the signal of the enable signal terminal VS and the signal of the coaxial socket 13 is at the first level (eg, low level), the selection control circuit 110 selects the output terminal to output a signal having the first level (for example, a low level) disconnection control signal; the switch control unit 120 controls the output end of the unit to be protected and the coaxial line according to the disconnection control signal with a first level (for example, a low level) output from the selected output end Disconnect between sockets 13.

In the first example: the enable signal terminal GPS-EN is a low level signal, the GNSS chip 11 does not work, and the power supply unit 12 does not work either. When a short circuit occurs inside the active antenna or at the clasp of the coaxial cable, the signal at the coaxial cable socket 13 is a low-level signal. Then the negative electrodes of the first diode AD1 and the second diode AD2 are both low-level signals, so that the base of the triode is at a low level, so as to control the triode to be turned off, and then the power supply unit 12 can be controlled to be disconnected from the active antenna. open to avoid the problem that the power supply unit 12 is burned out due to excessive current.

In the second example: the enable signal terminal GPS-EN is a low level signal, the GNSS chip 11 does not work, and the power supply unit 12 does not work either. When there is no short circuit inside the active antenna or at the joint of the coaxial cable, the negative electrode of the second diode AD2 is equivalent to an open circuit. In addition, the cathode of the first diode AD1 is a low-level signal, so that the base of the triode is low-level, so that the triode is controlled to be turned off, and the power supply unit 12 can be controlled to be disconnected from the active antenna. In this way, when the GNSS chip 11 does not work and the power supply unit 12 does not work, it can prevent the problem that the power supply unit 12 is burnt out due to excessive current when a short circuit occurs inside the active antenna or at the coaxial cable clasp.

In the third example: when the enable signal terminal GPS-EN is switched from a low-level signal to a high-level signal (for example, corresponding to a voltage of 1.8V), the GNSS chip 11 has just started to work, and the power supply unit 12 has also just started. Work. When a short circuit occurs inside the active antenna or at the joint of the coaxial cable, the signal at the coaxial cable socket 13 is a low-level signal, and the negative electrode of the second diode AD2 is a low-level signal. Then the cathode of the first diode AD1 is a high-level signal, and the cathode of the second diode AD2 is a low-level signal, so that the base of the triode is at a low level, thereby controlling the triode to turn off, and then the power supply unit can be controlled 12 is disconnected from the active antenna to avoid the problem that the power supply unit 12 is burned out due to excessive current.

In the fourth example: when the enable signal terminal GPS-EN is stable at a high level signal (for example, corresponding to a voltage of 1.8V), the GNSS chip 11 works stably, and the power supply unit 12 also works stably. When a short circuit occurs suddenly inside the active antenna or at the joint of the coaxial cable, the signal at the coaxial cable socket 13 is a low-level signal, and the negative electrode of the second diode AD2 is switched from a high-level signal to a low-level signal . In addition, the negative electrode of the first diode AD1 is a high-level signal, and the base of the triode is a low-level signal, so that the triode is controlled to be turned off, and then the power supply unit 12 can be controlled to be disconnected from the active antenna, so as to avoid the power supply unit 12 due to the current Oversized and burned out problem.

Exemplarily, when the signal at the enable signal terminal and the signal at the load connection terminal are both at the second level, the selection control circuit outputs a conduction control signal through the selection output terminal; the switch control unit controls the There is conduction between the output terminal of the unit to be protected and the load connection terminal. For example, when the signal of the enable signal terminal VS and the signal of the coaxial socket 13 are both at the second level (eg high level), the selection control circuit 110 selects the output terminal to output a second level (eg high level) The switch control unit 120 controls the connection between the output end of the unit to be protected and the coaxial socket 13 according to the conduction control signal with the second level (eg high level) output by the selected output end on.

In the first example: when the enable signal terminal GPS-EN is switched from a low-level signal to a high-level signal (for example, corresponding to a voltage of 1.8V), the GNSS chip 11 has just started to work, and the power supply unit 12 has also just started. Work. When there is no short circuit inside the active antenna or at the joint of the coaxial cable, the negative electrode of the second diode AD2 is equivalent to an open circuit. Then the first diode AD1 and the negative electrode of the first diode AD1 are high-level signals, so that the base of the triode is high-level, so as to control the conduction of the triode, and then the power supply unit 12 and the active antenna can be controlled to conduct. so that the power supply unit 12 can supply power to the active antenna normally.

In the second example: when the enable signal terminal GPS-EN is stable at a high level signal (for example, corresponding to a voltage of 1.8V), the GNSS chip 11 works stably, and the power supply unit 12 also works stably. When there is no short circuit inside the active antenna or at the joint of the coaxial cable, the negative electrode of the second diode AD2 is equivalent to a path. Then the negative electrodes of the first diode AD1 and the second diode AD2 are both high-level signals, so that the base of the triode is high-level, so as to control the conduction of the triode, and then the power supply unit 12 and the active antenna can be controlled. On, so that the power supply unit 12 can supply power to the active antenna normally.

It should be noted that, before the GNSS chip 11 and the power supply unit 12 are activated, the power supply unit 12 has no output voltage, and the transmission path of the radio frequency signal is in a voltage-free state. Therefore, the transmission path of the radio frequency signal is neither low level nor high The level can be understood as being in an open-circuit state (no-level state), so the cathode of the second diode is also in an open-circuit state, and its anode is also in an open-circuit state. Moreover, since the anodes of the first diode and the second diode are connected together, since the anode of the first diode is 1.8V, and the anode of the second diode has no level, the second and second The level of the anode of the pole tube will be consistent with the anode of the first diode. Therefore, if the anode of the first diode is low, the anode of the second diode is low. If the anode of the first diode is high, the anode of the second diode is high.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims (10)

1. a protection control circuit, is characterized in that, comprises: The selection control circuit is configured to output a signal through the selection output terminal according to the signal of the load connection terminal and the signal of the enable signal terminal of the unit to be protected; The switch control unit is configured to be connected to the selection output terminal, and according to the signal output from the selection output terminal, control the on and off between the output terminal of the unit to be protected and the load connection terminal. 2. The protection control circuit of claim 1, wherein the selection control circuit comprises an AND gate; The first input terminal of the AND gate is electrically connected to the enable signal terminal, the second input terminal of the AND gate is electrically connected to the load connection terminal, and the output terminal of the AND gate is used as the selection output terminal . 3. The protection control circuit of claim 2, wherein the AND gate comprises: a first resistor, a first diode and a second diode; The first end of the first resistor is connected to the reference power supply voltage end, and the second end of the first resistor is connected to the positive electrode of the first diode and the positive electrode of the second diode, respectively. the output of the AND gate; The cathode of the first diode is used as the first input end; The cathode of the second diode serves as the second input terminal. 4 . The protection control circuit according to claim 1 , wherein the protection control circuit further comprises: a first protection inductor; wherein the switch control unit passes the first protection inductor through the switch control unit. 5 . The device is connected to the load connection end. 5 . The protection control circuit according to claim 1 , wherein the protection control circuit further comprises: a second protection inductor; wherein the selection control circuit passes the second protection inductor through the selection control circuit. 6 . The device is connected to the load connection end. 6. The protection control circuit according to any one of claims 1-3, wherein the switch control unit comprises a first switch; The control end of the first switch is connected to the selection output end, the first end of the first switch is connected to the output end of the unit to be protected, and the second end of the first switch is connected to the load connection end connect. 7. The protection control circuit of claim 6, wherein the first switch comprises at least one of a triode and a metal oxide semiconductor field effect transistor. 8. A navigation system, characterized in that, comprising: an active antenna, a power supply unit and the protection control circuit according to any one of claims 1-7; The unit to be protected is the power supply unit, and the load connection end is connected to the active antenna. 9. A communication terminal, comprising: the navigation system according to claim 8. 10. A control method for a protection control circuit as claimed in any one of claims 1-7, characterized in that, comprising: When at least one of the signal of the enable signal terminal and the signal of the load connection terminal is at the first level, the selection control circuit outputs a disconnection control signal through the selection output terminal; the switch control unit The disconnection control signal output by the selection output terminal controls the disconnection between the output terminal of the unit to be protected and the load connection terminal; When the signal at the enable signal terminal and the signal at the load connection terminal are both at the second level, the selection control circuit outputs a conduction control signal through the selection output terminal; the switch control unit outputs a conduction control signal according to the selection output terminal The output conduction control signal controls the conduction between the output end of the unit to be protected and the load connection end.

Images