Rail transit-based output protection circuit

Abstract

The utility model provides an output protection circuit based on rail transit, which belongs to the technical field of electronic circuits and comprises a controlled switch circuit, an isolation power supply circuit, an MOS (metal oxide semiconductor) switch circuit and a current detection circuit. The controlled circuit is electrically connected between the MCU and the isolation power supply circuit to prevent the isolation power supply circuit from interfering with an MCU power supply when the isolation power supply circuit is turned on, the isolation power supply circuit is electrically connected with the MOS switching circuit, and the current detection circuit is electrically connected with the MCU, the MOS switching circuit and an output voltage negative electrode and is used for judging whether the output current is over-current. A rail transit output protection circuit is designed, and the safety of output control is improved by utilizing a series control mode of a two-way VCC3.3 V controlled switch circuit, an isolation power supply circuit, an MOS control circuit and an MOS switch circuit which are mutually incoherent.

Description

Technical Field

[0001] The utility model belongs to the technical field of electronic circuits, and in particular relates to a protection circuit based on rail transit output. Background Art

[0002] In the field of rail transit, output protection design is a key link to ensure the safe and stable operation of the system. Traditional power supply systems often lack effective output protection measures, which may cause damage to sensitive electronic equipment or even safety accidents in the event of power fluctuations or abnormal conditions. In addition, urban rail transit DC systems may encounter various faults and abnormal operating conditions during operation, which may threaten electrical equipment and personal safety. Therefore, the control and protection of DC power supply systems play an important role in ensuring the safe operation of rail transit.

[0003] By analyzing the low real-time and stability characteristics of traditional rail transit output relays, the present invention utilizes a dual-channel series isolated MOS switch circuit and real-time monitoring of the output current to significantly improve the safety, stability, real-time and load protection of the rail transit LCU. Utility Model Content

[0004] The purpose of the utility model is to provide a rail transit output protection circuit. The utility model aims to solve the problem of low real-time performance and low stability of traditional rail transit output relays.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] The rail transit output protection circuit includes: a controlled switch circuit, an isolated power supply circuit, a MOS switch circuit, and a current detection circuit; the controlled switch circuit is electrically connected between the MCU and the isolated power supply circuit to prevent the isolated power supply circuit from interfering with the MCU power supply when it is turned on, the isolated power supply circuit is electrically connected to the MOS switch circuit, and the current detection circuit is electrically connected to the MCU, the MOS switch circuit, and the negative pole of the output voltage, respectively, and is used to determine whether the output current is overcurrent.

[0007] As a preferred solution of the utility model, the controlled switch circuit is provided with two groups, namely a primary controlled switch circuit and a secondary controlled switch circuit. The primary controlled switch circuit is composed of resistors R6, R7, and MOS tube Q2. The resistor R6 is electrically connected between the G pole and the D pole of the MOS tube Q2. The S pole of the MOS tube Q2 is electrically connected to the resistor R7 and then grounded. The primary controlled switch circuit and the secondary controlled switch circuit receive the CTRL_1A signal and the CTRL_1B signal of the MCU respectively.

[0008] As a preferred solution of the utility model, the isolated power supply circuit is provided with two groups, namely a first isolated power supply circuit and a second isolated power supply circuit. The first isolated power supply circuit is composed of a power management chip U2, an isolation transformer T2, a rectifier chip D2, a resistor R8, a resistor R11, a resistor R12, a capacitor C5, a capacitor C6, and a capacitor C8. The power management chip U2 is electrically connected to the rectifier chip D2 through the isolation transformer T2. The resistor R11, the resistor R12, and the capacitor C5 are connected in parallel with each other. Pins 2 and 5 of the rectifier chip D2 are electrically connected to one end of the capacitor C5, and the other end of the capacitor C5 is electrically connected to pins 1 and 4 of the rectifier chip D2.

[0009] As a preferred solution of the utility model, the MOS switch circuit is provided with two groups, namely a first MOS switch circuit and a second MOS switch circuit, which are composed of a resistor R1, a resistor R3, a MOS tube Q1, and a capacitor C3. The resistor R1 is electrically connected to the G pole of the MOS tube Q1, and the resistor R3 and the capacitor C3 are electrically connected in series between the S pole and the D pole of the MOS tube Q1.

[0010] As a preferred solution of the utility model, the first MOS switch circuit and the second MOS switch circuit are electrically connected, and the MOS tube Q1 adopts a FCB070N65S3 high-current MOS tube with a withstand voltage of 650V and a maximum current of 44A.

[0011] As a preferred solution of the utility model, the current detection circuit is composed of a current detection chip U3, a capacitor C9, a capacitor C10, a diode D3, and a diode D4. The 3rd and 4th pins of the current detection chip U3 are connected in series with the diodes D3 and D4 and then grounded GND. The 6th pin of the current detection chip U3 is grounded GND after passing through the capacitor C10, and the 8th pin of the current detection chip U3 is grounded GND after passing through the capacitor C9.

[0012] As a preferred solution of the utility model, the first isolated power supply circuit, the first-level controlled switch circuit and the first MOS switch belt circuit together constitute a group of controlled switch circuits, and the second isolated power supply circuit, the second-level controlled switch circuit and the second MOS switch belt circuit constitute another group of controlled switch circuits.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] 1. The rail transit output protection circuit designed in this paper utilizes the series control method of independent dual-channel VCC_3.3V controlled switch circuit, isolated power supply circuit, MOS control circuit, and MOS switch circuit to improve the safety of output control.

[0015] 2. This design of rail transit output protection circuit monitors the output current information in real time, and determines whether there is overcurrent based on the current information, thereby determining whether to shut down the output power supply, thereby further ensuring the safety of the electrical circuit and load. Moreover, this design uses only a very small number of components for output protection and overcurrent protection, so that the output protection has good stability and the function of protecting the load, and the control current is high, the control is simple, the cost is low, and it is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0017] Figure 1 This is a schematic diagram of the utility model based on the rail transit output protection circuit;

[0018] Figure 2 This is a controlled switch circuit diagram based on the rail transit output protection circuit of the utility model;

[0019] Figure 3 This is the isolated power supply circuit and MOS switch circuit diagram based on the rail transit output protection circuit of the utility model;

[0020] Figure 4 This is a current detection circuit diagram of the utility model based on the rail transit output protection circuit;

[0021] Figure 5 This is a connection diagram of the utility model based on the rail transit output protection circuit. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the utility model in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] Example

[0024] See also Figure 1-5 , the utility model provides the following technical solutions:

[0025] Specific as Figure 1As shown, the rail transit output protection circuit includes: a controlled switching circuit, an isolated power supply circuit, a MOS switching circuit, and a current detection circuit; the controlled switching circuit is electrically connected between the MCU and the isolated power supply circuit to prevent the isolated power supply circuit from interfering with the MCU power supply when it is turned on, the isolated power supply circuit is electrically connected to the MOS switching circuit, and the current detection circuit is electrically connected to the MCU, the MOS switching circuit, and the negative pole of the output voltage, respectively, and is used to determine whether the output current is overcurrent.

[0026] Specific as Figure 2 As shown, the primary controlled switch circuit is composed of resistors R6, R7, and MOS tube Q2, and the secondary controlled switch circuit is composed of resistors R13, R14, and MOS tube Q4. The input voltage of the primary controlled switch circuit and the secondary controlled switch circuit are both 3.3V. The primary controlled switch circuit is turned on and off by the MCU through the CTRL_1A signal, and the secondary controlled switch circuit is turned on and off by the MCU through the CTRL_1B signal. They are respectively connected in series with the isolated power supply circuit and the MOS switch circuit to form a control output circuit, thereby improving the correctness and safety of the output.

[0027] Specific as Figure 3 As shown, the isolated power supply circuit is composed of a first isolated power supply circuit and a second isolated power supply circuit, and its purpose is to isolate the MCU power supply circuit from the high-voltage DC110V circuit to prevent the high-voltage circuit from interfering with and impacting the low-voltage circuit, wherein the first isolated power supply circuit is composed of a power management chip U1, an isolation transformer T1, a rectifier chip D1, a resistor R2, a resistor R4, a resistor R5, and capacitors C1, C2, and C4. The power management chip U1 is a chip MAX253ESA transformer driver chip, and capacitors C1, C2, and C4 are filter capacitors. The power management chip U2 is electrically connected to the rectifier chip D2 through the isolation transformer T2, and the resistors R11, R12, and C5 are connected in parallel with each other. The 2nd and 5th pins of the rectifier chip D2 are electrically connected to one end of the capacitor C5, and the other end of the capacitor C5 is electrically connected to the 1st and 4th pins of the rectifier chip D2, wherein the resistor R2 is a pull-up resistor, and the resistors R3 and R4 are load resistors. The first isolated power supply circuit, the first-level controlled switch circuit and the first MOS switch circuit together form a group of controlled switch circuits.

[0028] like Figure 3As shown, the MOS switch circuit is composed of a first MOS switch circuit and a second MOS switch circuit. Taking the first MOS switch circuit as an example, the first MOS switch circuit is composed of a resistor R1, a resistor R3, a MOS tube Q1, and a capacitor C3. The resistor R1 is electrically connected to the G pole of the MOS tube Q1, and the S pole and the D pole of the MOS tube Q1 are electrically connected in series with the resistor R3 and the capacitor C3, wherein the resistor R1 is a current limiting resistor, the MOS tube Q1 is an NMOS tube, and a FCB070N65S3 high current MOS tube is adopted. The resistor R3 and the capacitor C3 constitute an RC series protection circuit.

[0029] like Figure 4 As shown, the current detection circuit is composed of a current detection chip U3, a capacitor C9, a capacitor C10, a diode D3, and a diode D4. The 3rd and 4th pins of the current detection chip U3 are connected, and then the diodes D3 and D4 are connected in series in sequence to the ground GND. The 6th pin of the current detection chip U3 is connected to the ground GND through the capacitor C10. The 8th pin of the current detection chip U3 is connected to the ground GND through the capacitor C9. The current detection circuit converts the detected current into a voltage and inputs it to the MCU. The MCU determines whether the overcurrent is 2A-10A. When the overcurrent is 2A-10A for more than 100ms, it determines to turn off the MOS tubes Q1 and Q3 at the same time. The output safety is enhanced and the output circuit is protected.

[0030] In specific applications, the output current flows into the current detection circuit for detection, and the current detection circuit then converts the output current into a voltage and inputs it into the MCU. The MCU determines whether there is overcurrent and records the overcurrent time. When the overcurrent 2A-10A exceeds 100ms, the MCU outputs a CTRL_1A signal or a CTRL_1B signal to the controlled switch circuit. The output power is turned off through a control switch circuit composed of a controlled switch circuit, an isolation power supply circuit, and a MOS switch strip circuit to ensure the safety of the circuit and the load.

[0031] Finally, it should be noted that the above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. Based on rail transit output protection circuit, it is characterized by: include: Controlled switch circuit, isolated power supply circuit, MOS switch circuit, current detection circuit; The controlled switch circuit is electrically connected between the MCU and the isolation power supply circuit to prevent the isolation power supply circuit from interfering with the MCU power supply when it is turned on. The isolation power supply circuit is electrically connected to the MOS switch circuit. The MOS switch circuit is provided with two groups, namely, a first MOS switch circuit and a second MOS switch circuit. The first MOS switch circuit is composed of a resistor R1, a resistor R3, a MOS tube Q1, and a capacitor C3. The resistor R1 is electrically connected to the G pole of the MOS tube Q1. The S pole and the D pole of the MOS tube Q1 are electrically connected with a resistor R3 and a capacitor C3 in series. The current detection circuit is electrically connected to the MCU, the MOS switch circuit, and the negative pole of the output voltage respectively and is used to determine whether the output current is overcurrent. The current detection circuit is composed of a current detection chip U3, a capacitor C9, a capacitor C10, a diode D3, and a diode D4. The 3rd and 4th pins of the current detection chip U3 are connected, and then the diodes D3 and D4 are connected in series in sequence to ground GND. The 6th pin of the current detection chip U3 is connected to ground GND after passing through the capacitor C10. The 8th pin of the current detection chip U3 is connected to ground GND after passing through the capacitor C9.

2. The rail transit output protection circuit according to claim 1 is characterized in that: The controlled switch circuit is provided with two groups, namely a primary controlled switch circuit and a secondary controlled switch circuit. The primary controlled switch circuit is composed of resistors R6, R7, and MOS tube Q2. The resistor R6 is electrically connected between the G pole and the D pole of the MOS tube Q2. The S pole of the MOS tube Q2 is electrically connected to the resistor R7 and then grounded. The primary controlled switch circuit and the secondary controlled switch circuit receive the CTRL_1A signal and the CTRL_1B signal of the MCU respectively.

3. The rail transit output protection circuit according to claim 2 is characterized in that: The isolated power supply circuit is provided with two groups, namely a first isolated power supply circuit and a second isolated power supply circuit. The first isolated power supply circuit is composed of a power management chip U2, an isolation transformer T2, a rectifier chip D2, a resistor R8, a resistor R11, a resistor R12, a capacitor C5, a capacitor C6, and a capacitor C8. The power management chip U2 is electrically connected to the rectifier chip D2 through the isolation transformer T2. The resistor R11, the resistor R12, and the capacitor C5 are connected in parallel with each other. Pins 2 and 5 of the rectifier chip D2 are electrically connected to one end of the capacitor C5, and the other end of the capacitor C5 is electrically connected to pins 1 and 4 of the rectifier chip D2.

4. The rail transit output protection circuit according to claim 1 is characterized in that: The first MOS switch circuit and the second MOS switch circuit are electrically connected, and the MOS tube Q1 adopts a FCB070N65S3 high-current MOS tube with a withstand voltage of 650V and a maximum current of 44A.

5. The rail transit output protection circuit according to claim 3 is characterized in that: The first isolated power supply circuit, the primary controlled switch circuit and the first MOS switch belt circuit together form a group of controlled switch circuits, and the second isolated power supply circuit, the secondary controlled switch circuit and the second MOS switch belt circuit form another group of controlled switch circuits.

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