Current detection circuit for rail transit vehicle-mounted radio station

Abstract

The utility model discloses a current detection circuit for a rail transit vehicle-mounted radio station, which belongs to the field of rail transit vehicle-mounted radio stations and comprises a voltage acquisition circuit, a comparator circuit, an ADC (analog-to-digital conversion) circuit and an MCU (microprogrammed control unit) circuit. The voltage acquisition circuit samples an input voltage signal, and the comparator circuit is used for comparing the sampled voltage signal with a reference voltage and generating a comparison result; the ADC digital-to-analog conversion circuit converts an analog voltage signal into a digital signal, and the MCU circuit adjusts the measuring range and calculates the collected voltage and resistance values to obtain a current value. The device is simple in structure and low in cost, adapts to vehicle-mounted radio hardware, and adapts to current changes in different scenes through an adjustable measuring range design; and the current can be accurately monitored in real time under the conditions of high load and frequent communication, and corresponding protection measures are taken to ensure that the radio station normally works in each operation mode. As a part of an electronic device, the circuit works cooperatively with other equipment of the rail transit system, so that the safety and the operation efficiency of the system are improved.

Description

Technical Field

[0001] This patent relates to the field of vehicle-mounted radios for rail transit, and in particular to a current detection circuit for a vehicle-mounted radio for rail transit, which is used to detect the current of the vehicle-mounted radio in real time. Background Art

[0002] Urban transportation is booming, and rail transportation has become an indispensable part. Vehicles rely on radio communication to ensure efficient and safe operation of the system. In order to ensure that the radio can work normally in a complex operating environment, a reliable current detection circuit has become an indispensable key element. This circuit is used to monitor the status of the radio, detect abnormalities in real time and take protective measures, which is especially important in high-load and frequent communication situations. However, existing current detection circuits have defects and usually only have single-channel measurement, resulting in limited range. This is insufficient in high-load and frequent communication situations. Therefore, there is an urgent need for a stable and reliable current detection circuit with multi-channel measurement and adjustable range. Summary of the invention

[0003] Based on the problems existing in the prior art, the utility model provides a current detection circuit for rail transit vehicle-mounted radio stations, which uses a four-channel sampling circuit and has the characteristics of a large measurement range and a fast switching speed. The range can be automatically switched according to the size of the existing voltage, thereby realizing the precise measurement function of different currents. It combines the characteristics of fast response of analog sampling, digital reading and current digital transmission, and at the same time adopts an active amplifier circuit with low internal resistance to improve the measurement accuracy.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a current detection circuit for a rail transit vehicle-mounted radio station, comprising: a voltage acquisition circuit, a comparator circuit, an ADC analog-to-digital conversion circuit, and an MCU circuit, wherein the voltage acquisition circuit is respectively connected to the comparator circuit, the ADC analog-to-digital conversion circuit, and the MCU circuit, and the MCU circuit is respectively connected to the ADC analog-to-digital conversion circuit and the comparator circuit, wherein the voltage acquisition circuit is used to sample and amplify the input voltage signal, wherein the comparator circuit is used to compare the sampled voltage signal measured by the voltage acquisition circuit with the set reference voltage, and to generate a corresponding comparison result, i.e., a high level or a low level, wherein the ADC analog-to-digital conversion circuit is used to convert the analog voltage signal output by the voltage acquisition circuit into a digital signal that can be processed by the MCU controller chip, and wherein the MCU circuit is used to select the range of the acquisition voltage, and to calculate the sampled voltage value and resistance value to obtain the current value, thereby realizing the current measurement.

[0005] The utility model has the characteristics of simple circuit structure and low cost, and can be well adapted to the hardware circuit of the existing vehicle-mounted radio. Through the design of adjustable range, the current detection circuit can flexibly adapt to the changes in current intensity under different working scenarios. This flexibility allows the circuit to accurately monitor the current under high load and frequent communication conditions, ensuring that the radio works normally under various operating modes. The function of real-time current detection enables the system to perceive the changes in current intensity at any time and detect any abnormal conditions in time. When working under high load, corresponding protective measures can be taken in time to prevent the current from exceeding the set range, thereby ensuring the stability and reliability of the radio. In addition, as part of the electronic device, the current detection circuit works in coordination with other equipment in the rail transit system to realize real-time communication between vehicles and information exchange with the control center. This two-way communication mechanism effectively ensures that vehicles can obtain operating instructions, traffic information and guidance in emergency situations in a timely manner, further improving the safety and operating efficiency of the entire rail transit system. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is the overall structural diagram of the utility model;

[0007] Figure 2 It is a circuit diagram of the voltage acquisition circuit of the utility model;

[0008] Figure 3 It is a circuit diagram of the comparator circuit of the utility model;

[0009] Figure 4 It is a circuit diagram of the ADC analog-to-digital conversion circuit of the utility model;

[0010] Figure 5 It is a circuit diagram of the MCU circuit of the utility model;

[0011] Figure 6 It is a connection circuit diagram between the digital ground and the analog ground of the utility model. DETAILED DESCRIPTION

[0012] The specific implementation of the utility model is described in detail below in conjunction with the accompanying drawings:

[0013] like Figure 1As shown, a current detection circuit for a rail transit vehicle radio station includes: a voltage acquisition circuit, a comparator circuit, an ADC analog-to-digital conversion circuit, and an MCU circuit. The voltage acquisition circuit is connected to the comparator circuit, the ADC analog-to-digital conversion circuit, and the MCU circuit respectively, and the MCU circuit is connected to the ADC analog-to-digital conversion circuit and the comparator circuit respectively; the whole system collects the voltage used by the current vehicle radio station, the voltage acquisition circuit is responsible for sampling the input voltage signal, and amplifies it through the amplifier in the circuit and outputs it to the comparator circuit and the ADC analog-to-digital conversion circuit respectively, the comparator circuit compares the voltage signal measured by the voltage acquisition circuit with the set reference voltage, and generates a corresponding comparison result. When the voltage exceeding the current gear is collected, the comparator outputs an interrupt on the rising edge, triggering the MCU gear to switch to a higher range; the ADC analog-to-digital converter converts the analog voltage signal output by the comparator circuit into a digital signal that can be processed by the MCU, and transmits the voltage digital quantity to the MCU controller. The MCU controller adjusts the resistance value in the sampling circuit through different ranges, and calculates the current value through the calculation formula I=V / R set by the internal program according to the recorded sampling voltage value and the corresponding sampling resistance value, so as to achieve accurate current measurement.

[0014] like Figure 2As shown, the voltage acquisition circuit includes: resistors R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23, R101, R102, R103, R104, R105, R106, R107, R108, capacitors C101, C102, C103, C104, C105, C106, N-channel field effect transistor Q6 of model AON7544, P-channel field effect transistor Q3, Q4, Q5, Q7, Q8, Q9, Q10 of model AO3400, and current feedback of model TLV3201AIDBVR Amplifiers U9 and U10; wherein, resistors R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22 and R23, together with field effect transistors Q3, Q4, Q5, Q6, Q7, Q8, Q9 and Q10 form a variable range sampling circuit, resistors R20, R21, R22 and R23 are sampling resistors with different resistance values, and the corresponding current ranges are 1ma, 200ma, 1A and 5A respectively. The high and low levels output by the IO port of the MCU can control the opening and closing of the P-channel field effect transistor to realize the function of switching the voltage acquisition path corresponding to the current range. The function of the operational amplifier is to perform operational amplification on the collected signal, output it to the subsequent comparator circuit to determine the range, and output it to the ADC analog-to-digital conversion circuit for analog-to-digital conversion. The ADC analog-to-digital conversion circuit converts the collected analog signal into a digital signal and transmits it to the MCU circuit for processing.

[0015] The specific circuit of the voltage acquisition circuit is as follows: the input voltage V_input is connected to the drain of transistors Q6, Q3, Q5, Q4, respectively; the gate of transistor Q6 is connected to one end of resistor R15, one end of resistor R19 and the gate of transistor Q7, and then connected to the 16th pin SW_0.04R of U1 in the MCU circuit; the other end of resistor R15 is connected to the digital ground GND; the source of transistor Q6 is connected to one end of resistor R20 and the drain of transistor Q7, respectively; the gate of transistor Q3 is connected to one end of resistor R13, one end of resistor R16 and the gate of transistor Q8, and then connected to the 17th pin SW_0.02R of U1 in the MCU circuit; the other end of R13 is connected to the analog ground AGND; the source of transistor Q3 is connected to one end of resistor R21 and the drain of transistor Q8, respectively; the gate of transistor Q5 is connected to one end of resistor R14, one end of resistor R17 and the gate of transistor Q9, and then connected to the 18th pin SW_0 of U1 in the MCU circuit.1R is connected, the other end of R14 is connected to the analog ground AGND, the source of transistor Q5 is connected to one end of resistor R22 and the drain of transistor Q9 respectively, the gate of transistor Q4 is connected to one end of resistor R12, one end of resistor R18 and the gate of transistor Q10 respectively, and then connected to pin 19 SW_20R of U1 in the MCU circuit, the other end of R12 is connected to the drain of transistor Q10 and then connected to the analog ground GND, the source of transistor Q4 is connected to one end of resistor R23, the other end of resistor R20 is connected to the other end of R21, the other end of R22 and R23 respectively. The other end of R104 is connected to the analog ground AGND, the other end of R19, the other end of R16, the other end of R17 and the other end of R18 are connected to the analog ground AGND respectively, the sources of transistors Q7, Q8, Q9 and Q10 are connected in parallel and connected to one end of R104, the other end of R104 is connected to pin 3 of amplifier U9, pin 1 of U9 is connected to one end of resistor R103, one end of capacitor C101 and pin 3 of amplifier U10 respectively, pin 2 of U9 is connected to the analog ground AGND, pin 4 of U9 is connected to one end of resistor R101, one end of resistor R102 and pin The other end of capacitor C101 is connected, pin 5 of U9 is connected to one end of capacitor C102, one end of C103 and +3V3_A respectively, the other end of resistor R102 is connected to the other end of resistor R103, the other end of capacitor C102 is connected to the other end of capacitor C103 and then connected to analog ground AGND, the other end of resistor R101 is connected to analog ground AGND, pin 1 of U10 is connected to one end of resistor R107, one end of capacitor C104 and one end of resistor R108 respectively, pin 2 of U10 is connected to analog ground AGND, pin 4 of U10 is connected to resistor R105 One end of the resistor R106 and the other end of the capacitor C104 are connected, the 5th pin of U10 is connected to one end of the capacitor C106, one end of C106 and the power supply end +3V3_A respectively, the other end of the resistor R106 is connected to the other end of the resistor R107, the other end of the capacitor C105 is connected to the other end of the capacitor C106 and then connected to the analog ground AGND, the other end of the resistor R105 is connected to the analog ground AGND, the other end of the resistor R108 is respectively connected to the 3rd pin of the amplifier chip U7 in the comparator circuit and the 1st pin OUT1 of the ADC analog-to-digital conversion chip U8;.

[0016] like Figure 3 As shown, the comparator circuit includes: capacitors C17, C18, C19 and a current feedback amplifier U7 of model TLV3201AIDBVR; the amplifier U7 and the peripheral circuit form a comparator circuit to compare the voltage signal collected by the voltage acquisition circuit with the set reference voltage, and output high and low levels to the MCU circuit according to the comparison result, triggering the MCU controller to switch the corresponding range;

[0017] The specific circuit is as follows: pin 1 of U7 is connected to pin 13 TLIT_SW of chip U1 in the MCU circuit, pin 2 of U7 is connected to the analog ground AGND, pin 4 of U7 is connected to one end of capacitor C19, pin 5 of U7 is respectively connected to one end of capacitor C17, one end of capacitor C18 and the power supply end +3V3_A, the other end of capacitor C19 is connected to the analog ground AGND, and the other end of capacitor C17 is connected to the other end of capacitor C18 and then connected to the analog ground AGND.

[0018] like Figure 4 As shown, the ADC analog-to-digital conversion circuit includes an ADC analog-to-digital converter chip U8 of model MCP3421A0T-E / CH. The specific circuit is as follows: Pin 1 of U8 is connected to the output terminal OUT1 of the voltage acquisition circuit, Pins 2 and 5 are connected to the analog ground AGND, Pin 3 of U8 is connected to Pin 12 SCL of the MCU controller chip U1, Pin 4 of U8 is connected to Pin 11 SDA of the MCU circuit chip U1, and Pin 6 of U8 is connected to the power supply terminal +3V3_A. The analog-to-digital converter U8 converts the voltage analog quantity collected by the voltage acquisition circuit into a digital quantity, and transmits the data to the MCU for subsequent processing through the IIC bus, i.e., Pin 3 SCL and Pin 4 SDA of U8;

[0019] like Figure 5 As shown, the MCU circuit includes capacitors: C1, C2, C3 and a controller chip U1 of model STM8S003F3P6. U1 is used to switch the corresponding acquisition range, calculate the sampled voltage and resistance value, and obtain and process the digital current value;

[0020] The specific circuit is as follows: VCC is connected to one end of capacitor C1 and one end of capacitor C2, the other end of capacitor C1 is respectively connected to the other end of capacitor C2, one end of capacitor C3 and pin 9 VDD of U1 and then connected to the digital ground GND, the other end of capacitor C3 is connected to pin 8 of U1, pin 7 of U1 is connected to the digital ground GND, pins 2 and 3 of U1 are serial data ports for transmitting current value data, pin 11 SDA and pin 12 SLC are connected to the ADC analog-to-digital converter for receiving the digital signal output by the ADC analog-to-digital conversion circuit, pin 13 TLY_SW is connected to the comparator circuit for receiving the comparison result output by the comparator circuit and switching the range according to the result, pins 16 to 19 are connected to the voltage acquisition circuit for selecting different ranges and sampling the resistance; pins 1, 4, 5, 6, 10, 14, 15 and 20 are vacant.

[0021] like Figure 6As shown, in order to prevent the high-frequency noise of the digital signal from affecting the analog circuit, or the accuracy of the analog signal from being affected by the current fluctuation generated by the digital circuit, the utility model connects an inductor L1 of model CBW321609U101 in series between the digital ground GND and the analog AGND.

[0022] The working principle of the current detection circuit for a rail transit vehicle-mounted radio station of the utility model is as follows: the voltage acquisition circuit acquires the analog quantity of the input voltage, and the current range gear is selected through the MCU controller, that is, the high and low levels of the 16 to 19 pins of U1 are adjusted; for example, when the 19th pin SW_20R is at a high level and the other several pins are at a low level, the P-channel field effect tubes of Q4 and Q10 are turned on, the voltage sampling path of this range is opened, R23 is the sampling resistor at this time, and the corresponding current range is 1ma. Since this path is opened, a voltage difference will be generated at both ends of R23, so that the voltage acquisition is realized, and the collected voltage analog quantity is output to U The voltage amplifier circuit composed of U9 and U10 realizes signal amplification and outputs it to the comparator circuit and ADC analog-to-digital conversion circuit respectively. If the collected voltage exceeds the maximum value accepted by the current range, the comparator circuit will output a high level and be collected by the MCU. The MCU will switch the 18-pin SW_0.1R to a high level. At this time, Q6 and Q9 are turned on, and the path of the 200ma range corresponding to R22 is opened to realize the switching of the high-level position, and so on; if after switching, the collected voltage exceeds the maximum range designed for this circuit, all 16 to 19 of U1 are set to a low level and no data is collected. Under normal circumstances, the ADC analog-to-digital conversion circuit chip U8 converts the collected voltage digital quantity into analog-to-digital conversion, converts the analog signal into a digital signal that can be recognized by the MCU, and outputs the converted voltage digital quantity data to the MCU through the IIC bus, that is, the SCL and SDA terminals of U8. The MCU calculates the collected digital voltage value and resistance value through the formula I=V / R set by the program and outputs the corresponding current value. Finally, the digital value of the current is output through the serial data ports at pins 2 and 3 of U1 to realize the real-time numerical display and monitoring functions.

Claims

1. A current detection circuit for a rail transit vehicle radio, characterized in that: include: A voltage acquisition circuit, a comparator circuit, an ADC analog-to-digital conversion circuit, and an MCU circuit. The voltage acquisition circuit is connected to the comparator circuit, the ADC analog-to-digital conversion circuit, and the MCU circuit respectively. The MCU circuit is connected to the ADC analog-to-digital conversion circuit and the comparator circuit respectively. The voltage acquisition circuit is used to sample and amplify the input voltage signal. The comparator circuit is used to compare the sampled voltage signal measured by the voltage acquisition circuit with the set reference voltage and generate a corresponding comparison result, i.e., a high level or a low level. The ADC analog-to-digital conversion circuit is used to convert the analog voltage signal output by the voltage acquisition circuit into a digital signal that can be processed by the MCU controller chip. The MCU circuit is used to select the range of the acquisition voltage, and calculate the sampled voltage value and resistance value to obtain the current value to achieve current measurement.

2. A current detection circuit for a rail transit vehicle-mounted radio according to claim 1, characterized in that: The voltage acquisition circuit is as follows: the input voltage V_input is connected to the drain of transistors Q6, Q3, Q5, Q4, respectively; the gate of transistor Q6 is connected to one end of resistor R15, one end of resistor R19 and the gate of transistor Q7, and then connected to the 16th pin SW_0.04R of U1 in the MCU circuit; the other end of resistor R15 is connected to the digital ground GND; the source of transistor Q6 is connected to one end of resistor R20 and the drain of transistor Q7, respectively; the gate of transistor Q3 is connected to one end of resistor R13, one end of resistor R16 and the gate of transistor Q8, and then connected to the 17th pin SW_0.02R of U1 in the MCU circuit; the other end of R13 is connected to the analog ground AGND; the source of transistor Q3 is connected to one end of resistor R21 and the drain of transistor Q8, respectively; the gate of transistor Q5 is connected to one end of resistor R14, one end of resistor R17 and the gate of transistor Q9, and then connected to the 18th pin SW_0 of U1 in the MCU circuit.1R is connected, the other end of R14 is connected to the analog ground AGND, the source of transistor Q5 is connected to one end of resistor R22 and the drain of transistor Q9 respectively, the gate of transistor Q4 is connected to one end of resistor R12, one end of resistor R18 and the gate of transistor Q10 respectively, and then connected to pin 19 SW_20R of U1 in the MCU circuit, the other end of R12 is connected to the drain of transistor Q10 and then connected to the analog ground GND, the source of transistor Q4 is connected to one end of resistor R23, the other end of resistor R20 is connected to the other end of R21, the other end of R22 and the gate of R23 respectively. The other end is connected to the analog ground AGND, the other end of R19, the other end of R16, the other end of R17 and the other end of R18 are respectively connected to the analog ground AGND, the sources of transistors Q7, Q8, Q9 and Q10 are connected in parallel to one end of R104, the other end of R104 is connected to pin 3 of amplifier U9, pin 1 of U9 is respectively connected to one end of resistor R103, one end of capacitor C101 and pin 3 of amplifier U10, pin 2 of U9 is connected to the analog ground AGND, pin 4 of U9 is respectively connected to one end of resistor R101, one end of resistor R102 and capacitor C The other end of U10 is connected to the other end of resistor R107, one end of capacitor C104 and one end of resistor R108, the 2nd end of U10 is connected to the analog ground AGND, and the 4th end of U10 is connected to the resistor R107. 5, one end of resistor R106 and the other end of capacitor C104 are connected, pin 5 of U10 is respectively connected to one end of capacitor C106, one end of C106 and power supply terminal +3V3_A, the other end of resistor R106 is connected to the other end of resistor R107, the other end of capacitor C105 is connected to the other end of capacitor C106 and then connected to analog ground AGND, the other end of resistor R105 is connected to analog ground AGND, the other end of resistor R108 is respectively connected to pin 3 of amplifier chip U7 in the comparator circuit and pin 1 OUT1 of ADC analog-to-digital conversion chip U8;. The transistor Q6 is an N-channel field effect transistor of model AON7544, the transistors Q3, Q4, Q5, Q7, Q8, Q9, and Q10 are P-channel field effect transistors of model AO3400, and the amplifiers U9 and U10 are current feedback amplifiers of model TLV3201AIDBVR.

3. A current detection circuit for a rail transit vehicle-mounted radio according to claim 2, characterized in that: The comparator circuit is as follows: Pin 1 of the amplifier U7 is connected to Pin 13 TLIT_SW of the chip U1 in the MCU circuit, Pin 2 of U7 is connected to the analog ground AGND, Pin 4 of U7 is connected to one end of the capacitor C19, Pin 5 of U7 is respectively connected to one end of the capacitor C17, one end of the capacitor C18 and the power supply end +3V3_A, the other end of the capacitor C19 is connected to the analog ground AGND, and the other end of the capacitor C17 is connected to the other end of the capacitor C18 and then connected to the analog ground AGND; The amplifier U7 is a current feedback amplifier of model TLV3201AIDBVR.

4. The current detection circuit for a rail transit vehicle-mounted radio according to claim 2, characterized in that: The ADC analog-to-digital conversion circuit includes an ADC analog-to-digital converter chip U8, pin 2 of U8 is connected to the analog ground AGND, pin 3 of U8 is connected to pin 12 SCL of the MCU circuit chip U1, pin 4 of U8 is connected to pin 11 SDA of the MCU circuit chip U1, pin 5 of U8 is connected to the analog ground AGND, and pin 6 of U8 is connected to the power supply terminal +3V3_A; the model of the analog-to-digital converter chip U8 is MCP3421A0T-E / CH.

5. The current detection circuit for a rail transit vehicle-mounted radio according to claim 2, characterized in that: The MCU circuit includes a controller chip U1, VCC is connected to one end of capacitor C1 and one end of capacitor C2, the other end of capacitor C1 is respectively connected to the other end of capacitor C2, one end of capacitor C3 and pin 9 of U1 and then connected to the digital ground GND, the other end of capacitor C3 is connected to pin 8 of U1, pin 7 of U1 is connected to the digital ground GND, pins 2 and 3 of U1 are serial data ports for transmitting current value data, pin 11 SDA and pin 12 SLC are connected to the analog-to-digital conversion circuit, pin 13 TLY_SW is connected to the comparator circuit, pins 16 to 19 are used as selections of different ranges and are connected to the voltage acquisition circuit, and pins 1, 4, 5, 6, 10, 14, 15 and 20 are vacant.

6. The current detection circuit for a rail transit vehicle-mounted radio according to claim 2, characterized in that: An inductor L1 is connected in series between the digital ground GND and the analog AGND to prevent the high-frequency noise of the digital signal from affecting the analog circuit and the accuracy of the analog signal from being affected by the current fluctuation generated by the digital circuit.

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