A low-cost current load detection circuit and vehicle-mounted radio antenna

Abstract

This utility model relates to a low-cost current load detection circuit and a vehicle-mounted radio antenna, which can identify active and passive antennas and can be extended to various load current application scenarios with low application cost. The circuit includes: a sampling module and a detection module; the input terminal of the sampling module is connected to an external load, the first output terminal of the sampling module is connected to an external power supply and is connected to the first input terminal of the detection module, and the second output terminal of the sampling module is connected to the second input terminal of the detection module; the output terminal of the detection module is connected to an external MCU detection circuit.

Description

Technical Field

[0001] This utility model relates to the field of wireless communication technology, and in particular to a low-cost current load detection circuit and a vehicle-mounted radio antenna. Background Technology

[0002] Vehicle-mounted radio antennas come in two types: those with antenna amplifiers and those without, i.e., active antennas and passive antennas. Active antennas have a built-in low-noise amplifier (LNA) and filtering circuit, require an external power supply, and can compensate for transmission loss through two-stage signal amplification, achieving a gain of up to 18dBi, significantly improving weak signal reception capabilities. They also have strong anti-interference capabilities and are suitable for scenarios with complex electromagnetic environments (such as high-rise buildings and tunnels). Passive antennas are pure metal structures or ceramic dielectric antennas, without amplifiers or power supplies. They rely on antenna size (such as the area of ​​the ceramic sheet) to enhance the signal, achieving a gain of approximately 3dBi. They are also low in cost and small in size, but have stringent requirements for PCB layout and electromagnetic shielding. Different types of antennas require different radio reception parameters. In the past, the practice was to produce and ship two separate models, increasing operating costs.

[0003] A search of existing technical literature revealed a patent application with application number 201510192983.8, titled "Apparatus and Method for Vehicle-Mounted Terminal Compatible with Active and Passive Antennas." This patent includes: an antenna detection circuit for detecting whether the connected antenna is an active or passive antenna and outputting corresponding status information; a microcontroller for determining whether the antenna is active or passive based on the status information output by the antenna detection circuit and outputting corresponding control information; the microcontroller is connected to the antenna detection circuit; a memory for storing configuration files, including passive antenna configuration files and active antenna configuration files; and a central processing unit for retrieving the configuration file corresponding to the antenna from the memory based on the control information output by the microcontroller and configuring the antenna parameters in the configuration file into the receiver chip. This patent enables the same vehicle-mounted terminal to be compatible with both active and passive antennas and also achieves backward compatibility. However, this patent suffers from high cost and limited scalability. Utility Model Content

[0004] Therefore, it is necessary to provide a low-cost current load detection circuit and vehicle-mounted radio antenna to address the above-mentioned technical problems, so as to identify active and passive antennas, expand various load current application scenarios, and reduce application costs.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution: On the one hand, this utility model provides a low-cost current load detection circuit, including: a sampling module and a detection module; The sampling module has an external load connected to its input terminal, an external power supply connected to its first output terminal and connected to the first input terminal of the detection module, and a second output terminal connected to the second input terminal of the detection module. The output of the detection module is connected to an external MCU detection circuit.

[0006] Preferably, the detection module includes a detection transistor Q401, the first input terminal of the detection module is the emitter of the detection transistor Q401, the second input terminal of the detection module is the base of the detection transistor Q401, and the output terminal of the detection module is the collector of the detection transistor Q401.

[0007] Preferably, the sampling module includes: a sampling diode D402, a sampling resistor R425, a first diode D421, a first electrolytic capacitor E402, a second electrolytic capacitor E407, a first capacitor C430, a first resistor R405, a second resistor R414, and a third resistor R426. The input terminal of the sampling module is one end of the sampling resistor R425, the first output terminal of the sampling module is the anode of the sampling diode D402, and the second output terminal of the sampling module is the other end of the second resistor R414. One end of the sampling resistor R425 is connected to an external load and is connected to one end of the second resistor R414. The other end of the second resistor R414 is connected to the base of the detection transistor Q401. The other end of the sampling resistor R425 is connected to one end of the first resistor R405, one end of the first capacitor C430, the anode of the first electrolytic capacitor E402, the cathode of the sampling diode D402, and one end of the third resistor R426. The other end of the first resistor R405 is grounded, the other end of the first capacitor C430 is grounded, and the cathode of the first electrolytic capacitor E402 is grounded. The anode of the sampling diode D402 is connected to an external power supply and is connected to the other end of the third resistor R426, the cathode of the first diode D421, the anode of the second electrolytic capacitor E407, and the emitter of the detection transistor Q401. The anode of the first diode D421 is grounded, and the cathode of the second electrolytic capacitor E407 is grounded.

[0008] Preferably, one end of the sampling resistor R425 is connected to an external load, and an LC filter module is also included in between.

[0009] Preferably, the LC filter module includes: a first inductor LB401, a third capacitor C406, and a third electrolytic capacitor E403; One end of the first inductor LB401 is connected to an external load and is connected to one end of the third capacitor C406 and the anode of the third electrolytic capacitor E403, respectively. The other end of the third capacitor C406 is grounded and the cathode of the third electrolytic capacitor E403 is grounded. The other end of the first inductor LB401 is connected to one end of the sampling resistor R425 and one end of the second resistor R414, respectively.

[0010] Preferably, the collector of the detection transistor Q401 is connected to an external MCU detection circuit, and an anti-interference filter module is also included between them.

[0011] Preferably, the anti-interference filtering module includes: a fourth resistor R415, a second capacitor C402, a fifth resistor R403, and a Zener diode ZD403; One end of the fourth resistor R415 is connected to the collector of the detection transistor Q401, and the other end of the fourth resistor R415 is externally connected to the MCU detection circuit. It is also connected to one end of the second capacitor C402, one end of the fifth resistor R403, and the cathode of the Zener diode ZD403. The other end of the second capacitor C402 is grounded, the other end of the fifth resistor R403 is grounded, and the anode of the Zener diode ZD403 is grounded.

[0012] Preferably, the other end of the fourth resistor R415 is externally connected to the MCU detection circuit, and a sixth resistor R306 is also included in between.

[0013] Preferably, the detection transistor Q401 is a PNP type transistor.

[0014] On the other hand, this utility model provides a vehicle-mounted radio antenna, including the aforementioned low-cost current load detection circuit.

[0015] Compared with the prior art, the beneficial effects of this utility model are: This invention provides a low-cost current load detection circuit and vehicle-mounted radio antenna. By adding a simple antenna load detection circuit, the antenna type is determined based on the output level of the detection transistor, and the result is transmitted to the MCU detection circuit. The MCU recognizes the detection result and automatically switches the radio parameters, achieving the goal of using a single model with or without an antenna amplifier, reducing the number of models operated and lowering costs. The detection circuit is composed of conventional discrete components, making it simple and inexpensive. By adjusting the sampling resistor parameters, it can be easily expanded to various load current application scenarios, making it flexible in application. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a low-cost current load detection circuit architecture in one embodiment; Figure 2This is an extended schematic diagram of a low-cost current load detection circuit architecture in one embodiment; Figure 3 This is a schematic diagram of a low-cost current load detection circuit structure in one embodiment; Figure 4 This is a schematic diagram showing the connection of a low-cost current load detection circuit to the I / O detection port of the MCU detection circuit through a sixth resistor R306 in one embodiment. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0018] Example 1 like Figure 1 As shown, this embodiment proposes a low-cost current load detection circuit, including: a sampling module and a detection module; The sampling module has an external load connected to its input terminal, an external power supply connected to its first output terminal and connected to the first input terminal of the detection module, and a second output terminal connected to the second input terminal of the detection module. The output of the detection module is connected to an external MCU detection circuit.

[0019] The specific implementation method is as follows: When the antenna power interface is not connected to a load (passive antenna), no current flows through the sampling module. The base voltage and emitter voltage of the detection transistor Q401 are the same, so the detection transistor Q401 is in the cutoff state and outputs a low level. This is transmitted to the I / O detection terminal of the MCU detection circuit. The MCU detection circuit recognizes this state as a passive antenna and switches to passive antenna parameters. When the antenna power interface is connected to a load (active antenna), the active antenna consumes current through the sampling module, generating a voltage drop. The base voltage of the detection transistor Q401 is less than the emitter voltage of the detection transistor Q401 (adjust the sampling resistor value and power according to different loads to make the voltage drop greater than the Vbe conduction threshold). The detection transistor Q401 is in a saturated conduction state, and the collector voltage of the detection transistor Q401 rises, outputting a high-level state, which is transmitted to the I / O detection terminal of the MCU detection circuit. The MCU detection circuit recognizes this state as an active antenna and switches to active antenna parameters.

[0020] Example 2 A low-cost current load detection circuit includes: a sampling module and a detection module; The sampling module has an external load connected to its input terminal, an external power supply connected to its first output terminal and connected to the first input terminal of the detection module, and a second output terminal connected to the second input terminal of the detection module. The output of the detection module is connected to an external MCU detection circuit.

[0021] The specific implementation method is as follows: When the antenna power interface is not connected to a load (passive antenna), no current flows through the sampling module. The base voltage and emitter voltage of the detection transistor Q401 are the same, so the detection transistor Q401 is in the cutoff state and outputs a low level. This is transmitted to the I / O detection terminal of the MCU detection circuit. The MCU detection circuit recognizes this state as a passive antenna and switches to passive antenna parameters. When the antenna power interface is connected to a load (active antenna), the active antenna consumes current through the sampling module, generating a voltage drop. The base voltage of the detection transistor Q401 is less than the emitter voltage of the detection transistor Q401 (adjust the sampling resistor value and power according to different loads to make the voltage drop greater than the Vbe conduction threshold). The detection transistor Q401 is in a saturated conduction state, and the collector voltage of the detection transistor Q401 rises, outputting a high-level state, which is transmitted to the I / O detection terminal of the MCU detection circuit. The MCU detection circuit recognizes this state as an active antenna and switches to active antenna parameters.

[0022] The detection module includes a detection transistor Q401. The first input terminal of the detection module is the emitter of the detection transistor Q401, the second input terminal of the detection module is the base of the detection transistor Q401, and the output terminal of the detection module is the collector of the detection transistor Q401.

[0023] The sampling module includes: a sampling diode D402, a sampling resistor R425, a first diode D421, a first electrolytic capacitor E402, a second electrolytic capacitor E407, a first capacitor C430, a first resistor R405, a second resistor R414, and a third resistor R426. The input terminal of the sampling module is one end of the sampling resistor R425, the first output terminal of the sampling module is the anode of the sampling diode D402, and the second output terminal of the sampling module is the other end of the second resistor R414. One end of the sampling resistor R425 is connected to an external load and is connected to one end of the second resistor R414. The other end of the second resistor R414 is connected to the base of the detection transistor Q401. The other end of the sampling resistor R425 is connected to one end of the first resistor R405, one end of the first capacitor C430, the anode of the first electrolytic capacitor E402, the cathode of the sampling diode D402, and one end of the third resistor R426. The other end of the first resistor R405 is grounded, the other end of the first capacitor C430 is grounded, and the cathode of the first electrolytic capacitor E402 is grounded. The anode of the sampling diode D402 is connected to an external power supply and is connected to the other end of the third resistor R426, the cathode of the first diode D421, the anode of the second electrolytic capacitor E407, and the emitter of the detection transistor Q401. The anode of the first diode D421 is grounded, and the cathode of the second electrolytic capacitor E407 is grounded.

[0024] like Figure 2 As shown, one end of the sampling resistor R425 is connected to an external load, and an LC filter module is also included in between. The collector of the detection transistor Q401 is externally connected to the MCU detection circuit, and an anti-interference filter module is also included in between.

[0025] The LC filter module includes: a first inductor LB401, a third capacitor C406, and a third electrolytic capacitor E403; one end of the first inductor LB401 is connected to an external load and is connected to one end of the third capacitor C406 and the anode of the third electrolytic capacitor E403, respectively; the other end of the third capacitor C406 is grounded; the cathode of the third electrolytic capacitor E403 is grounded; and the other end of the first inductor LB401 is connected to one end of the sampling resistor R425 and one end of the second resistor R414, respectively.

[0026] The anti-interference filtering module includes: a fourth resistor R415, a second capacitor C402, a fifth resistor R403, and a Zener diode ZD403; one end of the fourth resistor R415 is connected to the collector of the detection transistor Q401, and the other end of the fourth resistor R415 is externally connected to the MCU detection circuit, and is connected to one end of the second capacitor C402, one end of the fifth resistor R403, and the cathode of the Zener diode ZD403 respectively; the other end of the second capacitor C402 is grounded, the other end of the fifth resistor R403 is grounded, and the anode of the Zener diode ZD403 is grounded.

[0027] like Figure 4 As shown, the other end of the fourth resistor R415 is connected to the MCU detection circuit, and a sixth resistor R306 is also included in between.

[0028] The detection transistor Q401 is a PNP type transistor.

[0029] Based on the above, we get the following: Figure 3 The diagram shows a low-cost current load detection circuit structure.

[0030] Example 3 A low-cost current load detection circuit includes: a sampling module and a detection module; The sampling module has an external load connected to its input terminal, an external power supply connected to its first output terminal and connected to the first input terminal of the detection module, and a second output terminal connected to the second input terminal of the detection module. The output of the detection module is connected to an external MCU detection circuit.

[0031] The specific implementation method is as follows: When the antenna power interface is not connected to a load (passive antenna), no current flows through the sampling module. The base voltage and emitter voltage of the detection transistor Q401 are the same, so the detection transistor Q401 is in the cutoff state and outputs a low level. This is transmitted to the I / O detection terminal of the MCU detection circuit. The MCU detection circuit recognizes this state as a passive antenna and switches to passive antenna parameters. When the antenna power interface is connected to a load (active antenna), the active antenna consumes current through the sampling module, generating a voltage drop. The base voltage of the detection transistor Q401 is less than the emitter voltage of the detection transistor Q401 (adjust the sampling resistor value and power according to different loads to make the voltage drop greater than the Vbe conduction threshold). The detection transistor Q401 is in a saturated conduction state, and the collector voltage of the detection transistor Q401 rises, outputting a high-level state, which is transmitted to the I / O detection terminal of the MCU detection circuit. The MCU detection circuit recognizes this state as an active antenna and switches to active antenna parameters.

[0032] The detection module includes a detection transistor Q401. The first input terminal of the detection module is the emitter of the detection transistor Q401, the second input terminal of the detection module is the base of the detection transistor Q401, and the output terminal of the detection module is the collector of the detection transistor Q401.

[0033] The sampling module includes: a sampling diode D402, a sampling resistor R425, a first diode D421, a first electrolytic capacitor E402, a second electrolytic capacitor E407, a first capacitor C430, a first resistor R405, a second resistor R414, and a third resistor R426. The input terminal of the sampling module is one end of the sampling resistor R425, the first output terminal of the sampling module is the anode of the sampling diode D402, and the second output terminal of the sampling module is the other end of the second resistor R414. One end of the sampling resistor R425 is connected to an external load and is connected to one end of the second resistor R414. The other end of the second resistor R414 is connected to the base of the detection transistor Q401. The other end of the sampling resistor R425 is connected to one end of the first resistor R405, one end of the first capacitor C430, the anode of the first electrolytic capacitor E402, the cathode of the sampling diode D402, and one end of the third resistor R426. The other end of the first resistor R405 is grounded, the other end of the first capacitor C430 is grounded, and the cathode of the first electrolytic capacitor E402 is grounded. The anode of the sampling diode D402 is connected to an external power supply and is connected to the other end of the third resistor R426, the cathode of the first diode D421, the anode of the second electrolytic capacitor E407, and the emitter of the detection transistor Q401. The anode of the first diode D421 is grounded, and the cathode of the second electrolytic capacitor E407 is grounded.

[0034] One end of the sampling resistor R425 is connected to an external load, and an LC filter module is also included in between.

[0035] The LC filter module includes: a first inductor LB401, a third capacitor C406, and a third electrolytic capacitor E403; One end of the first inductor LB401 is connected to an external load and is connected to one end of the third capacitor C406 and the anode of the third electrolytic capacitor E403, respectively. The other end of the third capacitor C406 is grounded and the cathode of the third electrolytic capacitor E403 is grounded. The other end of the first inductor LB401 is connected to one end of the sampling resistor R425 and one end of the second resistor R414, respectively.

[0036] The collector of the detection transistor Q401 is connected to an external MCU detection circuit, and an anti-interference filter module is also included between them.

[0037] The anti-interference filtering module includes: a fourth resistor R415, a second capacitor C402, a fifth resistor R403, and a Zener diode ZD403; One end of the fourth resistor R415 is connected to the collector of the detection transistor Q401, and the other end of the fourth resistor R415 is externally connected to the MCU detection circuit. It is also connected to one end of the second capacitor C402, one end of the fifth resistor R403, and the cathode of the Zener diode ZD403. The other end of the second capacitor C402 is grounded, the other end of the fifth resistor R403 is grounded, and the anode of the Zener diode ZD403 is grounded.

[0038] The other end of the fourth resistor R415 is connected to the MCU detection circuit, and a sixth resistor R306 is also included in between.

[0039] The detection transistor Q401 is a PNP type transistor.

[0040] Based on the above, this embodiment proposes a vehicle-mounted radio antenna, including the aforementioned low-cost current load detection circuit.

Claims

1. A low cost current load detection circuit, characterized by, include: Sampling module and detection module; The sampling module has an external load connected to its input terminal, an external power supply connected to its first output terminal and connected to the first input terminal of the detection module, and a second output terminal connected to the second input terminal of the detection module. The output of the detection module is connected to an external MCU detection circuit.

2. The low cost current load detection circuit of claim 1, wherein, The detection module includes a detection transistor Q401. The first input terminal of the detection module is the emitter of the detection transistor Q401, the second input terminal of the detection module is the base of the detection transistor Q401, and the output terminal of the detection module is the collector of the detection transistor Q401.

3. The low-cost current load detection circuit according to claim 2, characterized in that, The sampling module includes: a sampling diode D402, a sampling resistor R425, a first diode D421, a first electrolytic capacitor E402, a second electrolytic capacitor E407, a first capacitor C430, a first resistor R405, a second resistor R414, and a third resistor R426. The input terminal of the sampling module is one end of the sampling resistor R425, the first output terminal of the sampling module is the anode of the sampling diode D402, and the second output terminal of the sampling module is the other end of the second resistor R414. One end of the sampling resistor R425 is connected to an external load and is connected to one end of the second resistor R414. The other end of the second resistor R414 is connected to the base of the detection transistor Q401. The other end of the sampling resistor R425 is connected to one end of the first resistor R405, one end of the first capacitor C430, the anode of the first electrolytic capacitor E402, the cathode of the sampling diode D402, and one end of the third resistor R426. The other end of the first resistor R405 is grounded, the other end of the first capacitor C430 is grounded, and the cathode of the first electrolytic capacitor E402 is grounded. The anode of the sampling diode D402 is connected to an external power supply and is connected to the other end of the third resistor R426, the cathode of the first diode D421, the anode of the second electrolytic capacitor E407, and the emitter of the detection transistor Q401. The anode of the first diode D421 is grounded, and the cathode of the second electrolytic capacitor E407 is grounded.

4. The low-cost current load detection circuit according to claim 3, characterized in that, One end of the sampling resistor R425 is connected to an external load, and an LC filter module is also included in between.

5. The low-cost current load detection circuit according to claim 4, characterized in that, The LC filter module includes: a first inductor LB401, a third capacitor C406, and a third electrolytic capacitor E403; One end of the first inductor LB401 is connected to an external load and is connected to one end of the third capacitor C406 and the anode of the third electrolytic capacitor E403, respectively. The other end of the third capacitor C406 is grounded and the cathode of the third electrolytic capacitor E403 is grounded. The other end of the first inductor LB401 is connected to one end of the sampling resistor R425 and one end of the second resistor R414, respectively.

6. The low-cost current load detection circuit according to claim 2, characterized in that, The collector of the detection transistor Q401 is connected to an external MCU detection circuit, and an anti-interference filter module is also included between them.

7. The low-cost current load detection circuit according to claim 6, characterized in that, The anti-interference filtering module includes: a fourth resistor R415, a second capacitor C402, a fifth resistor R403, and a Zener diode ZD403; One end of the fourth resistor R415 is connected to the collector of the detection transistor Q401, and the other end of the fourth resistor R415 is externally connected to the MCU detection circuit. It is also connected to one end of the second capacitor C402, one end of the fifth resistor R403, and the cathode of the Zener diode ZD403. The other end of the second capacitor C402 is grounded, the other end of the fifth resistor R403 is grounded, and the anode of the Zener diode ZD403 is grounded.

8. The low-cost current load detection circuit according to claim 7, characterized in that, The other end of the fourth resistor R415 is connected to the MCU detection circuit, and a sixth resistor R306 is also included in between.

9. The low-cost current load detection circuit according to claim 2, characterized in that, The detection transistor Q401 is a PNP type transistor.

10. A vehicle-mounted radio antenna, characterized in that, The current load detection circuit includes any one of claims 1 to 9.

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