Railway safety equipment with two-way redundant power supply

Abstract

The railway safety equipment comprises a redundant power supply circuit, a power distributor, a controller and a main circuit, the output end of the power distributor is connected to the controller and the main circuit, and the input end of the power distributor is connected to the redundant power supply circuit; the redundant power supply circuit comprises a power output terminal, a first gated field effect transistor, a pull-down resistor, a first P-channel field effect transistor, a second P-channel field effect transistor, a third P-channel field effect transistor and a voltage division circuit, and a second diode is connected in parallel between the drain electrode and the source electrode of the second P-channel field effect transistor. And the positive electrode of the second diode is connected with the drain electrode of the second P-channel field effect transistor. Compared with the prior art, the invention can prevent reverse flow into the main power supply interface to break down other electric equipment when the standby power supply supplies power, and can improve the switching speed while quickly cutting off the standby circuit after the main power supply is conducted.

Description

Technical Field

[0001] The invention relates to the field of railway communication safety, and in particular to a railway safety device with dual redundant power supply. Background Art

[0002] To ensure the normal operation of safety equipment, safety equipment is often equipped with dual redundant 24V DC power supplies. The safety equipment is required to be able to work normally when any power supply is disconnected. When one of the power supplies is disconnected, it can immediately switch to the other power supply to ensure the uninterrupted operation of the equipment.

[0003] In the prior art, circuit switching mostly uses relays, which are bulky and have a slow switching speed. In addition, some technical personnel in this field have tried to use semiconductors to achieve the switching of reserve power supplies, but such circuits are still relatively complex in structure and cannot be switched to the main circuit in time when the main circuit resumes power supply, resulting in poor voltage stability, damage to precision components in safety equipment, or easy to reverse the output voltage of the power supply. Summary of the invention

[0004] The purpose of the present invention is to provide a railway safety device with dual redundant power supply, which can prevent the backup power supply from flowing back into the main power supply interface and breaking down other electrical equipment, and quickly cut off the backup circuit after the main power supply is turned on, while improving the switching speed.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A railway safety device with dual redundant power supply comprises a redundant power supply circuit, a power distributor, a controller and a main circuit, wherein the output end of the power distributor is respectively connected to the controller and the main circuit, and the input end is connected to the redundant power supply circuit, the redundant power supply circuit comprises a power output terminal, a first gated field effect transistor, a pull-down resistor, a first P-channel field effect transistor, a second P-channel field effect transistor, a third P-channel field effect transistor and a voltage divider circuit, a second diode is connected in parallel between the drain and source of the second P-channel field effect transistor, the anode of the second diode is connected to the drain of the second P-channel field effect transistor, and the cathode is connected to the source of the second P-channel field effect transistor, a third diode is connected in parallel between the drain and source of the third P-channel field effect transistor, the anode of the third diode is connected to the drain of the third P-channel field effect transistor, and the cathode is connected to the anode of the third P-channel field effect transistor,

[0007] The source of the first P-channel field effect transistor is connected to the positive electrode of the backup DC power supply, the gate is connected to the first end of the pull-down resistor, and the drain is connected to the drain of the second P-channel field effect transistor. The gate of the second P-channel field effect transistor is connected to the first end of the pull-down resistor, and the source is connected to the power output terminal. The second end of the pull-down resistor is grounded, and the first end is connected to the positive electrode of the main DC power supply. One end of the voltage divider circuit is connected to the positive electrode of the main DC power supply, and the other end is grounded. The voltage divider output end is connected to the gate of the first gated field effect transistor. The gate of the third P-channel field effect transistor is grounded through the drain and source of the first gated field effect transistor, the drain is connected to the positive electrode of the main DC power supply, and the source is connected to the power output terminal.

[0008] The first gate-controlled field effect transistor is an N-channel field effect transistor, a source of which is grounded, and a drain of which is connected to the gate of the third P-channel field effect transistor.

[0009] The redundant power supply circuit also includes a current limiting resistor, one end of which is respectively connected to the gate of the third P-channel field effect transistor and the drain of the first gated field effect transistor, and the other end of which is connected to the power output terminal.

[0010] A fourth diode is connected in parallel between the drain and source of the first gated field effect transistor, the anode of the fourth diode is connected to the source of the first gated field effect transistor, and the cathode of the fourth diode is connected to the drain of the first gated field effect transistor.

[0011] The fourth diode is integrated in the first gate-controlled field effect transistor.

[0012] The voltage-dividing resistor is formed by two fixed-value resistors with equal resistance values ​​connected in series.

[0013] The second diode is integrated in the second P-channel field effect transistor.

[0014] The third diode is integrated in the third P-channel field effect transistor.

[0015] A first diode is connected in parallel between the drain and source of the first P-channel field effect transistor, the anode of the first diode is connected to the drain of the first P-channel field effect transistor, and the cathode of the first diode is connected to the source of the first P-channel field effect transistor.

[0016] The first diode is integrated in the first P-channel field effect transistor.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] On the basis of realizing automatic switching, the main components are selected from semiconductor devices, so that the volume can be reduced. In addition, only four MOS tubes are used to realize all the functions of the circuit, and there are no comparators and other devices, which further reduces the overall volume.

[0019] On the premise of reducing the volume by the above means, the gates of the first P-channel field effect transistor and the second P-channel field effect transistor are designed to be grounded through a pull-down resistor and connected to the main DC power supply. When the main power supply is restored, the first P-channel field effect transistor and the second P-channel field effect transistor can be quickly cut off to complete the switching of the power supply source from the backup DC power supply to the main DC power supply. In parallel, in combination with the method of connecting the negative electrode of the third P-channel field effect transistor and the corresponding third triode to the power output terminal, it can be avoided that the current flows backward from the power output terminal to the main DC power supply side under the power supply of the backup DC power supply, and breaks down or damages other devices connected to the main DC power supply.

[0020] Through the design of the second diode and the third diode, it can be ensured that the second P-channel field effect transistor and the third P-channel field effect transistor can be normally turned on without the need for complex peripheral circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention;

[0022] Figure 2 A schematic diagram of the circuit principle of the redundant power supply circuit of the present invention;

[0023] Among them: 1. power distributor, 2. controller, 3. main circuit, 4. redundant power supply circuit, PWR_24V1, main DC power supply, PWR_24V2, backup DC power supply, V1, first gate field effect transistor, V2, first P-channel field effect transistor, V3, third P-channel field effect transistor, V4, second P-channel field effect transistor, R1, pull-down resistor, R2, current limiting resistor, R3, first voltage dividing resistor, R4, second voltage dividing resistor, 24VOUT, power output terminal. DETAILED DESCRIPTION

[0024] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0026] In the description of the present invention, it should be noted that, in addition, the terms "proximal", "distal" and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. Physical quantities in formulas, if not separately marked, should be understood as basic quantities of the basic units of the International System of Units, or derived quantities derived from basic quantities through mathematical operations such as multiplication, division, differentiation or integration.

[0027] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] A railway safety device with dual redundant power supply, such as Figure 1 As shown, it includes a redundant power supply circuit 4, a power distributor 1, a controller 2 and a main circuit 3. The output end of the power distributor 1 is connected to the controller 2 and the main circuit 3 respectively, and the input end is connected to the redundant power supply circuit 4. Figure 2 As shown, the redundant power supply circuit 4 includes a power output terminal 24VOUT, a first gated field effect transistor V1, a pull-down resistor R1, a first P-channel field effect transistor V2, a second P-channel field effect transistor V4, a third P-channel field effect transistor V3 and a voltage divider circuit, a second diode is connected in parallel between the drain and source of the second P-channel field effect transistor V4, the anode of the second diode is connected to the drain of the second P-channel field effect transistor V4, and the cathode is connected to the source of the second P-channel field effect transistor V4, a third diode is connected in parallel between the drain and source of the third P-channel field effect transistor V3, the anode of the third diode is connected to the drain of the third P-channel field effect transistor V3, and the cathode is connected to the anode of the third P-channel field effect transistor V3,

[0029] The source of the first P-channel field effect transistor V2 is connected to the positive electrode of the backup DC power supply PWR_24V2, the gate is connected to the first end of the pull-down resistor R1, and the drain is connected to the drain of the second P-channel field effect transistor V4. The gate of the second P-channel field effect transistor V4 is connected to the first end of the pull-down resistor R1, and the source is connected to the power output terminal 24VOUT. The second end of the pull-down resistor R1 is grounded, and the first end is connected to the positive electrode of the main DC power supply PWR_24V1. One end of the voltage divider circuit is connected to the positive electrode of the main DC power supply PWR_24V1, and the other end is grounded. The voltage divider output end is connected to the gate of the first gate-controlled field effect transistor V1. The gate of the third P-channel field effect transistor V3 is grounded through the drain and source of the first gate-controlled field effect transistor V1, the drain is connected to the positive electrode of the main DC power supply PWR_24V1, and the source is connected to the power output terminal 24VOUT.

[0030] On the basis of realizing automatic switching, the main components are selected from semiconductor devices, so that the volume can be reduced. In addition, only four MOS tubes are used to realize all the functions of the circuit, and there are no comparators and other devices, which further reduces the overall volume.

[0031] On the premise of reducing the volume by the above means, the gates of the first P-channel field effect transistor V2 and the second P-channel field effect transistor V4 are designed to be grounded through the pull-down resistor R1 and connected to the main DC power supply PWR_24V1. When the main power supply is restored, the first P-channel field effect transistor V2 and the second P-channel field effect transistor V4 can be quickly cut off to complete the switching of the power supply source from the backup DC power supply PWR_24V2 to the main DC power supply PWR_24V1. In parallel, in combination with the third P-channel field effect transistor V3 and the corresponding third triode, the negative electrode is connected to the power output terminal 24VOUT, so that the current can be prevented from flowing backward from the power output terminal 24VOUT to the main DC power supply PWR_24V1 side when the backup DC power supply is supplied, thereby breaking down or damaging other devices connected to the main DC power supply PWR_24V1.

[0032] Through the design of the second diode and the third diode, it can be ensured that the second P-channel field effect transistor V4 and the third P-channel field effect transistor V3 can be normally turned on without the need for complex peripheral circuits.

[0033] In this embodiment, the first gate-controlled field effect transistor V1 is an N-channel field effect transistor, the source is grounded, and the drain is connected to the gate of the third P-channel field effect transistor V3. This can reduce costs. In addition, the redundant power supply circuit 4 also includes a current limiting resistor R2, one end of which is respectively connected to the gate of the third P-channel field effect transistor V3 and the drain of the first gate-controlled field effect transistor V1, and the other end is connected to the power output terminal 24VOUT. In addition, a fourth diode is connected in parallel between the drain and source of the first gate-controlled field effect transistor V1, and the positive electrode of the fourth diode is connected to the source of the first gate-controlled field effect transistor V1, and the negative electrode is connected to the drain of the first gate-controlled field effect transistor V1. In this embodiment, the fourth diode is integrated in the first gate-controlled field effect transistor V1, so that cost can be taken into account.

[0034] Generally, a voltage-dividing resistor is formed by connecting two fixed resistors with equal resistance in series. In this embodiment, a first voltage-dividing resistor R3 and a second voltage-dividing resistor R4 are connected in series.

[0035] In this embodiment, the second diode is integrated into the second P-channel field effect transistor V4, and the third diode is integrated into the third P-channel field effect transistor V3.

[0036] Similarly, a first diode is connected in parallel between the drain and source of the first P-channel field effect transistor V2, the anode of the first diode is connected to the drain of the first P-channel field effect transistor V2, the cathode is connected to the source of the first P-channel field effect transistor V2, and the first diode is integrated in the first P-channel field effect transistor V2.

[0037] In this embodiment, the first P-channel field effect transistor V2, the second P-channel field effect transistor V4, and the third P-channel field effect transistor V3 can be selected from the Si7315DN model, with a drain-source saturation voltage VDS of up to 150V, a drain-source saturation current ID of up to 8.9A, a VGS of less than plus or minus 30V, and an on-resistance of less than 315mΩ.

[0038] The first gate field effect transistor V1 can be 2N7002, which is used for small signal control. It does not require high drain-source saturation current ID, and 110mA meets the requirement.

[0039] The pull-down resistor R1, the current limiting resistor R2, the first voltage-dividing resistor R3 and the second voltage-dividing resistor R4 all use 1M ohm fixed-value resistors. The maximum static current under 24V power supply is 24uA. The output voltage of the backup DC power supply PWR_24V2 and the main DC power supply PWR_24V1 are both 24V.

[0040] Here’s how this application works:

[0041] When it is assumed that both the backup DC power supply PWR_24V2 and the main DC power supply PWR_24V1 have no voltage output, all field effect transistors are in a closed state, and the power output terminal 24VOUT has no output voltage.

[0042] When the backup DC power supply PWR_24V2 is powered on and the main DC power supply PWR_24V1 has no output, at this time, the first gated field effect tube V1 is not turned on, and the first P-channel field effect tube V2 will be turned on because of the positive voltage difference between the drain and the gate. After being turned on, there is no positive voltage difference between the drain and the gate of the second P-channel field effect tube V4 in the initial state, so it is not turned on. However, due to the existence of the second diode, the second diode will be turned on. At this time, there will be a certain voltage drop on the second diode, generally about 0.4V, which is specifically determined by the model of the second diode. At this time, the source of the second P-channel field effect tube V4 forms a voltage close to 24V, and a positive voltage is formed between the source and the gate of the second P-channel field effect tube V4. Difference, so the second P-channel field effect transistor V4 is turned on, and the power supply of the backup DC power supply PWR_24V2 is supplied to the outside through the first P-channel field effect transistor V2 and the second P-channel field effect transistor V4 through the power output terminal 24VOUT. At this time, although the source of the third P-channel field effect transistor V3 obtains a voltage of 24V, since the first gate field effect transistor V1 is not turned on, the gate of the third P-channel field effect transistor V3 is in a disconnected state and a positive voltage difference cannot be formed. Therefore, the third P-channel field effect transistor V3 is not turned on, and the third diode is connected to the power output terminal 24VOUT as a negative pole, and the power output terminal 24VOUT cannot flow back to the main DC power supply PWR_24V1 through the third diode.

[0043] When the backup DC power supply PWR_24V2 supplies power, the main DC power supply PWR_24V1 switches from a no-power state to a powered state. At this time, first, the first gated field effect transistor V1 will be turned on. Since the first gated field effect transistor V1 is turned on, the power output terminal 24VOUT provides a 24V voltage to the source of the third P-channel field effect transistor V3, forming a positive voltage difference between the source and the gate. Therefore, the third P-channel field effect transistor V3 is turned on, and almost at the same time, at the moment when the main DC power supply PWR_24V1 outputs the voltage, the gate voltage of the first P-channel field effect transistor V2 and the second P-channel field effect transistor V4 is 24V, and a positive voltage difference cannot be formed between the source and the gate. Therefore, the first P-channel field effect transistor V2 and the second P-channel field effect transistor V4 will be turned off, and since the cathode of the second diode is toward the power output terminal 24VOUT, current cannot pass.

[0044] When both the backup DC power supply PWR_24V2 and the main DC power supply PWR_24V1 have no voltage output, the main DC power supply PWR_24V1 switches from a no-power state to a powered state. At this time, the first P-channel field effect transistor V2 and the second P-channel field effect transistor V4 cannot form a positive voltage difference between the source and the gate, and are in an off state. The first gated field effect transistor V1 will be turned on, but since the source of the third P-channel field effect transistor V3 has no voltage, a positive voltage difference cannot be formed between the source and the gate, so it cannot be turned on. However, due to the existence of the third transistor, current can flow to the power output terminal 24VOUT through the third transistor. At this time, the source of the third P-channel field effect transistor V3 obtains a 24V voltage, and a positive voltage difference is formed between the source and the gate of the third P-channel field effect transistor V3, and the third P-channel field effect transistor V3 is turned on. Similarly, since the cathode of the second diode is toward the power output terminal 24VOUT, current cannot pass through, which can protect other devices on the backup DC power supply PWR_24V2.

Claims

1. A railway safety device with dual redundant power supply, comprising a redundant power supply circuit, a power distributor, a controller and a main circuit, wherein the output end of the power distributor is respectively connected to the controller and the main circuit, and the input end is connected to the redundant power supply circuit, characterized in that: The redundant power supply circuit includes a power output terminal, a first gated field effect transistor, a pull-down resistor, a first P-channel field effect transistor, a second P-channel field effect transistor, a third P-channel field effect transistor and a voltage divider circuit, a second diode is connected in parallel between the drain and source of the second P-channel field effect transistor, the anode of the second diode is connected to the drain of the second P-channel field effect transistor, and the cathode is connected to the source of the second P-channel field effect transistor, a third diode is connected in parallel between the drain and source of the third P-channel field effect transistor, the anode of the third diode is connected to the drain of the third P-channel field effect transistor, and the cathode is connected to the anode of the third P-channel field effect transistor, The source of the first P-channel field effect transistor is connected to the positive electrode of the backup DC power supply, the gate is connected to the first end of the pull-down resistor, and the drain is connected to the drain of the second P-channel field effect transistor. The gate of the second P-channel field effect transistor is connected to the first end of the pull-down resistor, and the source is connected to the power output terminal. The second end of the pull-down resistor is grounded, and the first end is connected to the positive electrode of the main DC power supply. One end of the voltage divider circuit is connected to the positive electrode of the main DC power supply, and the other end is grounded. The voltage divider output end is connected to the gate of the first gated field effect transistor. The gate of the third P-channel field effect transistor is grounded through the drain and source of the first gated field effect transistor, the drain is connected to the positive electrode of the main DC power supply, and the source is connected to the power output terminal.

2. A railway safety device with dual redundant power supply according to claim 1, characterized in that: The first gate-controlled field effect transistor is an N-channel field effect transistor, a source of which is grounded, and a drain of which is connected to the gate of the third P-channel field effect transistor.

3. The railway safety device with dual redundant power supply according to claim 2, characterized in that: The redundant power supply circuit also includes a current limiting resistor, one end of which is respectively connected to the gate of the third P-channel field effect transistor and the drain of the first gated field effect transistor, and the other end is connected to the power output terminal.

4. The railway safety device with dual redundant power supply according to claim 2, characterized in that: A fourth diode is connected in parallel between the drain and source of the first gated field effect transistor, the anode of the fourth diode is connected to the source of the first gated field effect transistor, and the cathode of the fourth diode is connected to the drain of the first gated field effect transistor.

5. The railway safety device with dual redundant power supply according to claim 4, characterized in that: The fourth diode is integrated in the first gate-controlled field effect transistor.

6. The railway safety device with dual redundant power supply according to claim 1, characterized in that: The voltage-dividing resistor is formed by two fixed-value resistors with equal resistance values ​​connected in series.

7. The railway safety device with dual redundant power supply according to claim 1, characterized in that: The second diode is integrated in the second P-channel field effect transistor.

8. The railway safety device with dual redundant power supply according to claim 1, characterized in that: The third diode is integrated in the third P-channel field effect transistor.

9. The railway safety device with dual redundant power supply according to claim 1, characterized in that: A first diode is connected in parallel between the drain and source of the first P-channel field effect transistor, the anode of the first diode is connected to the drain of the first P-channel field effect transistor, and the cathode of the first diode is connected to the source of the first P-channel field effect transistor.

10. The railway safety device with dual redundant power supply according to claim 9, characterized in that: The first diode is integrated in the first P-channel field effect transistor.

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