Power supply equipment with protection function

Abstract

The utility model discloses power supply equipment with a protection function. The power supply equipment comprises a power supply input circuit and an output protection circuit, one end of the power supply input circuit is connected with commercial power, the other end of the power supply input circuit is connected with the output protection circuit, and the output protection circuit is connected with a load; the power supply input circuit comprises an isolation transformation circuit and a power supply circuit; one end of the isolation transformation circuit is connected with commercial power, the other end of the isolation transformation circuit is respectively connected with the power supply circuit and the output protection circuit, and the power supply circuit is connected with the output protection circuit. According to the utility model, the technical problem of how to instantly judge the load state and control the on-off of the relay according to the load state so as to guarantee the circuit safety is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply equipment, in particular to a power supply equipment with a protection function. Background Art

[0002] Existing power supply equipment only includes an isolation transformer, a fuse, and a switch. If the operator fails to turn off the switch in time, open circuit protection cannot be achieved, and there is still a risk of accidental electric shock. At the same time, the fuse needs to be replaced after a short circuit protection, which causes inconvenience in work. When operators repair and debug electricity meters on site, they often use the mains power supply directly, or simply use an isolation transformer for power supply. During the debugging process, it is inevitable to touch the electricity meter, resulting in a huge safety hazard in the process of testing the electricity meter circuit. It is also inconvenient to carry large factory calibration equipment. According to national and international standards, electricity meters have low power consumption and only use a simple small power supply. Therefore, in order to ensure safe use of electricity, there is an urgent need to improve miniaturized power supply equipment. Patent document with application number CN201520488260.2 discloses a fuse box and a car with a fuse box, a fuse and at least one relay, and also includes an electronic control unit ECU. The fuse includes a first fuse and at least one second fuse. The electronic control unit (ECU) is connected to at least one relay via the first fuse, the at least one relay is connected to an electrical device via the second fuse, and both the ECU and the at least one relay are connected to a power supply. The ECU controls the operating state of the at least one relay, the first fuse protects the ECU, and the second fuse protects the electrical device. Therefore, a power supply with a protective function is urgently needed to address the technical problem of how to instantly determine the load status and control the opening and closing of the relay based on the load status, thereby ensuring circuit safety. Utility Model Content

[0003] The main purpose of the utility model is to provide a power supply device with a protection function, aiming to solve the technical problem of how to instantly judge the load status and control the opening and closing of the relay according to the load status, thereby ensuring circuit safety.

[0004] To achieve the above-mentioned object, the present invention provides a power supply device with a protection function, wherein the power supply device with a protection function includes:

[0005] Power input circuit and output protection circuit;

[0006] One end of the power input circuit is connected to the mains, the other end of the power input circuit is connected to the output protection circuit, and the output protection circuit is connected to the load;

[0007] The power input circuit includes an isolation transformer circuit and a power supply circuit; one end of the isolation transformer circuit is connected to the mains, and the other end of the isolation transformer circuit is respectively connected to the power supply circuit and the output protection circuit, and the power supply circuit is connected to the output protection circuit.

[0008] In one of the preferred solutions, the isolation transformer circuit includes an isolation transformer T1; pin 1 of the isolation transformer T1 is connected to the mains input neutral terminal, pin 5 of the isolation transformer T1 is connected to the mains input live terminal, and pins 6 and 10 of the isolation transformer T1 are connected to the power supply circuit.

[0009] In one of the preferred embodiments, the power supply circuit includes an industrial frequency power transformer T2, a first power supply circuit, and a second power supply circuit; pins 1 and 5 of the industrial frequency power transformer T2 are connected to the isolation transformer circuit, pins 6 and 7 of the industrial frequency power transformer T2 are connected to the first power supply circuit, the first power supply circuit is connected to the output protection circuit, pins 9 and 10 of the industrial frequency power transformer T2 are connected to the second power supply circuit, and the second power supply circuit is connected to the output protection circuit.

[0010] In one of the preferred solutions, the first power supply circuit includes a diode D2 and a capacitor C6; the anode of the diode D2 is connected to pin 7 of the power frequency power transformer T2, the cathode of the diode D2 is respectively connected to the capacitor C6 and the output protection circuit, and the other end of the capacitor C6 is respectively connected to pins 5, 6, and 9 of the power frequency power transformer T2 and the ground.

[0011] In one of the preferred solutions, the second power supply circuit includes a diode D1 and a capacitor C2; the anode of the diode D1 is connected to pin 10 of the power frequency power transformer T2, the cathode of the diode D1 is connected to the capacitor C2 and the output protection circuit, and the other end of the capacitor C2 is respectively connected to pins 5, 6, and 9 of the power frequency power transformer T2 and the ground.

[0012] In one preferred embodiment, the output protection circuit includes a relay JD1, a relay JD2, a relay JD3, a switch K1, a light-emitting diode LED1, a freewheeling diode D6, a thermistor RT2, a thermistor RT3, a freewheeling diode D5, a resistor R4, a diode D3, a transistor Q1, and a freewheeling diode D4;

[0013] Pin 1 of the relay JD1 is connected to pin 2 of the relay JD2 and the anode of the freewheeling diode D6, pin 2 of the relay JD1 is connected to the cathode of the light-emitting diode LED1 and the freewheeling diode D6, pin 3 of the relay JD1 is connected to the power supply circuit, pin 4 of the relay JD1 is connected to the thermistor RT2, the other end of the thermistor RT2 is connected to the electric energy meter through the live terminal, one end of the thermistor RT3 is connected to the electric energy meter through the neutral terminal, the other end of the thermistor RT3 is connected to pin 4 of the relay JD2, pin 3 of the relay JD2 is connected to the resistor R4 and the anode of the diode D3, and the Pin 2 is connected to the cathode of the freewheeling diode D5, the cathode of the diode D3 is connected to the base of the transistor Q1, the collector of the transistor Q1 is respectively connected to pin 1 of the relay JD3 and the anode of the freewheeling diode D4, pin 2 of the relay JD3 is respectively connected to the cathode of the freewheeling diode D4 and the power supply circuit, pin 3 of the relay JD3 is connected to the power supply circuit and the switch K1, and the other end of the switch K1 is respectively connected to pin 4 of the relay JD3 and the other end of the light-emitting diode LED1; pin 1 of the relay JD2, the anode of the freewheeling diode D5, the emitter of the transistor Q1 and the other end of the resistor R4 are respectively connected to the ground and the power supply circuit.

[0014] In one of the preferred embodiments, the output protection circuit further includes a current limiting circuit; the current limiting circuit includes a resistor R2, a resistor R3, and a resistor R6; one end of the resistor R2 is connected to the base of the transistor Q1, the other end of the resistor R2 is connected to the cathode of the diode D3, one end of the resistor R3 is connected to the collector of the transistor Q1, the other end of the resistor R3 is respectively connected to the anode of the freewheeling diode D4 and pin 1 of the relay JD3, one end of the resistor R6 is connected to the light-emitting diode LED1, and the other end of the resistor R6 is respectively connected to the freewheeling diode D6 and pin 2 of the relay JD1.

[0015] In one of the preferred solutions, the output protection circuit further includes a filter circuit; the filter circuit includes a capacitor C5; one end of the capacitor C5 is connected to the cathode of the diode D3, and the other end of the capacitor C5 is respectively connected to the ground and the power supply circuit.

[0016] In one preferred embodiment, the relay JD1 includes a drive coil and a contact switch.

[0017] In one preferred solution, the relay JD1 has the same structure as the relay JD2 and the relay JD3.

[0018] In the above technical solution of the present utility model, the power supply device with a protection function includes: a power input circuit and an output protection circuit; one end of the power input circuit is connected to the mains, the other end of the power input circuit is connected to the output protection circuit, and the output protection circuit is connected to the load; the power input circuit includes an isolation transformer circuit and a power supply circuit; one end of the isolation transformer circuit is connected to the mains, the other end of the isolation transformer circuit is connected to the power supply circuit and the output protection circuit, respectively, and the power supply circuit is connected to the output protection circuit. The utility model solves the technical problem of how to instantly determine the load status and control the opening and closing of the relay according to the load status, thereby ensuring circuit safety.

[0019] In the utility model, after the input live wire and the input neutral wire are connected to the mains, isolated alternating current is output through the isolation transformer circuit, and the isolated alternating current is output through the power supply circuit to power the output protection circuit. The output protection circuit controls whether the output live wire and the output neutral wire are conductive according to whether the load is short-circuited or open-circuited. The utility model has a simple structure and is easy to use. It can realize open-circuit protection and can repeat short-circuit protection multiple times without replacing components, which greatly improves safety and practicality, meets the miniaturization requirements of power supply equipment, and is easy to carry.

[0020] In the present invention, the output side is completely electrically insulated from the mains side through an isolation transformer circuit, thereby ensuring safe power use on the output side. The input AC power is converted into a multi-volt DC voltage through a power supply circuit to power the output protection circuit, thereby meeting the different volt power supply requirements of the output protection circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the implementation methods or the description of the prior art. Obviously, the drawings described below are only some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0022] Figure 1 This is a schematic diagram of a power supply device with a protection function according to an embodiment of the present utility model;

[0023] Figure 2 This is a schematic diagram of a power input circuit according to an embodiment of the present utility model;

[0024] Figure 3 This is a schematic diagram of an output protection circuit according to an embodiment of the present utility model;

[0025] Figure 4 This is a flow chart of the output protection circuit according to an embodiment of the present invention.

[0026] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] In addition, in this utility model, the terms "first," "second," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include at least one of such features.

[0029] Moreover, the technical solutions between the various embodiments of the present invention can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0030] See also Figure 1 According to one aspect of the present invention, the present invention provides a power supply device with a protection function, wherein the power supply device with a protection function includes:

[0031] Power input circuit and output protection circuit;

[0032] One end of the power input circuit is connected to the mains, the other end of the power input circuit is connected to the output protection circuit, and the output protection circuit is connected to the load;

[0033] The power input circuit includes an isolation transformer circuit and a power supply circuit; one end of the isolation transformer circuit is connected to the mains, the other end of the isolation transformer circuit is connected to the power supply circuit, and the power supply circuit is connected to the output protection circuit.

[0034] Specifically, in this embodiment, see Figure 2The isolation transformer circuit includes an isolation transformer T1; pin 1 of the isolation transformer T1 is connected to the mains input neutral terminal, pin 5 of the isolation transformer T1 is connected to the mains input live terminal, pin 6 of the isolation transformer T1 is respectively connected to the power supply circuit and the output protection circuit, and pin 10 of the isolation transformer T1 is respectively connected to the power supply circuit and the output protection circuit; the isolation transformer circuit completely isolates the mains side electrical power from the L1-N1 electrical power on the output side of the isolation transformer T1 through the isolation transformer T1 to ensure the safety of the output side; the isolation transformer T1 is an isolation transformer with a turns ratio of 1:1, inputs an AC 220V voltage, and outputs an AC 220V voltage.

[0035] Specifically, in this embodiment, the power supply circuit includes an industrial frequency power transformer T2, a first power supply circuit, and a second power supply circuit; pin 1 of the industrial frequency power transformer T2 is respectively connected to pin 10 of the isolation transformer T1 and the live wire L1, and is connected to the output protection circuit through the live wire L1; pin 5 of the industrial frequency power transformer T2 is respectively connected to pin 6 of the isolation transformer T1, the neutral wire N1, and the ground terminal, and is connected to the output protection circuit through the neutral wire N1; pins 6 and 7 of the industrial frequency power transformer T2 are connected to the first power supply circuit, which is connected to the output protection circuit; pins 9 and 10 of the industrial frequency power transformer T2 are connected to the second power supply circuit, which is connected to the output protection circuit; the input side of the industrial frequency power transformer T2 inputs 220V AC, outputs a DC voltage of 12V through pins 9 and 10 of the industrial frequency transformer T2 and the second power supply circuit, and outputs a DC voltage of 24V through pins 6 and 7 of the industrial frequency transformer T2 and the first power supply circuit. Both the DC voltage of 12V and the DC voltage of 24V are power supplies for the output protection circuit.

[0036] Specifically, in this embodiment, the first power supply circuit includes a diode D2 and a capacitor C6; the anode of the diode D2 is connected to pin 7 of the power frequency power transformer T2, the cathode of the diode D2 is respectively connected to the capacitor C6 and the output protection circuit, and the other end of the capacitor C6 is respectively connected to pins 5, 6, and 9 of the power frequency power transformer T2 and the ground; the diode D2 is a rectifier diode, and the capacitor C6 is a filter capacitor; the 220V AC power connected to the input side is output as a 24V DC voltage to the output protection circuit through the first power supply circuit.

[0037] Specifically, in this embodiment, the second power supply circuit includes a diode D1 and a capacitor C2; the anode of the diode D1 is connected to pin 10 of the power frequency power transformer T2, the cathode of the diode D1 is connected to the capacitor C2 and the output protection circuit, and the other end of the capacitor C2 is respectively connected to pins 5, 6, and 9 of the power frequency power transformer T2 and the ground terminal; the power frequency transformer inputs 220V AC power, which is rectified by pins 9 and 10, and filtered by the diode D1, and outputs a DC voltage of 12V to the output protection circuit.

[0038] Specifically, in this embodiment, see Figure 3 The output protection circuit includes a relay JD1, a relay JD2, a relay JD3, a switch K1, a light-emitting diode LED1, a freewheeling diode D6, a thermistor RT2, a thermistor RT3, a freewheeling diode D5, a resistor R4, a diode D3, a transistor Q1 and a freewheeling diode D4; pin 1 of the relay JD1 is respectively connected to pin 2 of the relay JD2 and the anode of the freewheeling diode D6, pin 2 of the relay JD1 is respectively connected to the cathode of the light-emitting diode LED1 and the freewheeling diode D6, pin 3 of the relay JD1 is connected to the power supply circuit, pin 4 of the relay JD1 is connected to the thermistor RT2, the other end of the thermistor RT2 is connected to the electric energy meter through the output live wire terminal L2, one end of the thermistor RT3 is connected to the electric energy meter through the output neutral wire terminal N2, the other end of the thermistor RT3 is connected to pin 4 of the relay JD2, and pin 3 of the relay JD2 is respectively connected to the The resistor R4 is connected to the anode of the diode D3, the pin 2 of the relay JD2 is connected to the cathode of the freewheeling diode D5, the cathode of the diode D3 is connected to the base of the transistor Q1, the collector of the transistor Q1 is respectively connected to the pin 1 of the relay JD3 and the anode of the freewheeling diode D4, the pin 2 of the relay JD3 is respectively connected to the cathode of the freewheeling diode D4 and the power supply circuit, the pin 3 of the relay JD3 is connected to the power supply circuit and the switch K1, and the other end of the switch K1 is respectively connected to the pin 4 of the relay JD3 and the other end of the light-emitting diode LED1; the pin 1 of the relay JD2, the anode of the freewheeling diode D5, the emitter of the transistor Q1 and the other end of the resistor R4 are respectively connected to the ground and the power supply circuit; the freewheeling diode D4, the freewheeling diode D5 and the freewheeling diode D6 are used for the relay to release and provide a release reverse current path for the relay inductor; the switch K1 is a lockless switch.

[0039] Specifically, in this embodiment, the output protection circuit also includes a current limiting circuit; the current limiting circuit includes a resistor R2, a resistor R3 and a resistor R6; one end of the resistor R2 is connected to the base of the transistor Q1, the other end of the resistor R2 is connected to the cathode of the diode D3, one end of the resistor R3 is connected to the collector of the transistor Q1, the other end of the resistor R3 is respectively connected to the anode of the freewheeling diode D4 and pin 1 of the relay JD3, one end of the resistor R6 is connected to the light-emitting diode LED1, and the other end of the resistor R6 is respectively connected to the freewheeling diode D6 and pin 2 of the relay JD1.

[0040] Specifically, in this embodiment, the output protection circuit further includes a filter circuit; the filter circuit includes a capacitor C5; one end of the capacitor C5 is connected to the cathode of the diode D3, and the other end of the capacitor C5 is respectively connected to the ground and the power supply circuit.

[0041] Specifically, in this embodiment, the relay JD1 includes a drive coil and a contact switch.

[0042] Specifically, in this embodiment, the relay JD1 has the same structure as the relay JD2 and the relay JD3.

[0043] Specifically, in this embodiment, see Figure 4When the key switch K1 is pressed, the switch K1 is a non-locking switch and will automatically disconnect when released. The 24V power supply output from the first power supply circuit passes through the switch K1, the light-emitting diode LED1, the resistor R6, the relay JD1 drive coil, the relay JD2 drive coil, and finally reaches the ground terminal, forming a closed loop. The light-emitting diode LED1 lights up, and the contacts of relay JD1 and relay JD2 are closed. 220V is output through the output live wire terminal L2 and the output neutral wire terminal N2 to power the energy meter. It is determined whether the power supply terminal of the energy meter is open. If the power supply terminal of the energy meter is open, the current is zero. The voltage of resistor R4 is zero. After being rectified by diode D3, the base voltage of transistor Q1 is driven to zero. Transistor Q1 is not conducting, the coil of relay JD3 is not driven, and the contact is in the disconnected state; the coils of relay JD1 and relay JD2 are not driven either, the contacts are disconnected, the output live terminal L2 and the output neutral terminal N2 do not output voltage, the power supply protection takes effect, and the process ends; if the power supply terminal of the energy meter is not open, the current is approximately between a few mA and tens of mA according to the power consumption of the energy meter. The voltage drop of resistor R4 is equal to the resistance value of resistor R4 multiplied by the current. The voltage is driven after being rectified by diode D3. Transistor Q1, transistor Q1 is turned on, relay JD3 coil is driven, and contacts are closed; further determine whether the power supply terminal of the energy meter is short-circuited. If the power supply terminal of the energy meter is not short-circuited, the output live terminal L2 and the output neutral terminal N2 always output 220V, and the power supply of the energy meter is normal; if the power supply terminal of the energy meter is short-circuited, the thermistor RT2 and thermistor RT3 will be activated, the resistance value will increase, the current will decrease, and the voltage of the resistor R4 will decrease. After rectification by diode D3, the base voltage of the transistor Q1 will decrease, the transistor Q1 will not be turned on, the relay JD3 coil will not be driven, and the contacts will be in the open state. state; the coils of relay JD1 and relay JD2 are not driven, the contacts are disconnected, the output live terminal L2 and the output neutral terminal N2 do not output voltage, and the power supply protection takes effect; the output protection circuit determines whether the load is in an open circuit, short circuit or normal power supply state by detecting the current in the power supply loop, and controls the opening or closing of the relay according to the load state, thereby improving the safety of operation; the utility model is not only used for powering electric energy meters, but can also be used as a power supply equipment for maintenance and debugging of other low-power equipment. If the power of the power supply equipment needs to be increased, it can be done by selecting an adaptive isolation transformer and a voltage divider resistor R4.

[0044] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. All equivalent structural transformations made based on the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, within the scope of the present invention are included in the patent protection scope of the present invention.

Claims

1. A power supply device with a protection function, characterized in that: include: Power input circuit and output protection circuit; One end of the power input circuit is connected to the mains, the other end of the power input circuit is connected to the output protection circuit, and the output protection circuit is connected to the load; The power input circuit includes an isolation transformer circuit and a power supply circuit; One end of the isolation transformer circuit is connected to the mains, and the other end of the isolation transformer circuit is respectively connected to the power supply circuit and the output protection circuit, and the power supply circuit is connected to the output protection circuit.

2. The power supply device with protection function according to claim 1, characterized in that: The isolation transformer circuit includes an isolation transformer T1; pin 1 of the isolation transformer T1 is connected to the mains input neutral terminal, pin 5 of the isolation transformer T1 is connected to the mains input live terminal, and pins 6 and 10 of the isolation transformer T1 are connected to the power supply circuit.

3. A power supply device with a protection function according to any one of claims 1 to 2, characterized in that: The power supply circuit includes an industrial frequency power transformer T2, a first power supply circuit and a second power supply circuit; pins 1 and 5 of the industrial frequency power transformer T2 are connected to the isolation transformer circuit, pins 6 and 7 of the industrial frequency power transformer T2 are connected to the first power supply circuit, the first power supply circuit is connected to the output protection circuit, pins 9 and 10 of the industrial frequency power transformer T2 are connected to the second power supply circuit, and the second power supply circuit is connected to the output protection circuit.

4. The power supply device with protection function according to claim 3, characterized in that: The first power supply circuit includes a diode D2 and a capacitor C6; the anode of the diode D2 is connected to pin 7 of the power frequency power transformer T2, the cathode of the diode D2 is respectively connected to the capacitor C6 and the output protection circuit, and the other end of the capacitor C6 is respectively connected to pins 5, 6, and 9 of the power frequency power transformer T2 and the ground.

5. The power supply device with protection function according to claim 3, characterized in that: The second power supply circuit includes a diode D1 and a capacitor C2; the anode of the diode D1 is connected to pin 10 of the power frequency power transformer T2, the cathode of the diode D1 is connected to the capacitor C2 and the output protection circuit, and the other end of the capacitor C2 is respectively connected to pins 5, 6, and 9 of the power frequency power transformer T2 and the ground.

6. A power supply device with a protection function according to any one of claims 1-2, characterized in that: The output protection circuit includes a relay JD1, a relay JD2, a relay JD3, a switch K1, a light-emitting diode LED1, a freewheeling diode D6, a thermistor RT2, a thermistor RT3, a freewheeling diode D5, a resistor R4, a diode D3, a transistor Q1 and a freewheeling diode D4; Pin 1 of the relay JD1 is connected to pin 2 of the relay JD2 and the anode of the freewheeling diode D6, pin 2 of the relay JD1 is connected to the cathode of the light-emitting diode LED1 and the freewheeling diode D6, pin 3 of the relay JD1 is connected to the power supply circuit, pin 4 of the relay JD1 is connected to the thermistor RT2, the other end of the thermistor RT2 is connected to the electric energy meter through the live terminal, one end of the thermistor RT3 is connected to the electric energy meter through the neutral terminal, the other end of the thermistor RT3 is connected to pin 4 of the relay JD2, pin 3 of the relay JD2 is connected to the resistor R4 and the anode of the diode D3, and the Pin 2 is connected to the cathode of the freewheeling diode D5, the cathode of the diode D3 is connected to the base of the transistor Q1, the collector of the transistor Q1 is respectively connected to pin 1 of the relay JD3 and the anode of the freewheeling diode D4, pin 2 of the relay JD3 is respectively connected to the cathode of the freewheeling diode D4 and the power supply circuit, pin 3 of the relay JD3 is connected to the power supply circuit and the switch K1, and the other end of the switch K1 is respectively connected to pin 4 of the relay JD3 and the other end of the light-emitting diode LED1; pin 1 of the relay JD2, the anode of the freewheeling diode D5, the emitter of the transistor Q1 and the other end of the resistor R4 are respectively connected to the ground and the power supply circuit.

7. The power supply device with protection function according to claim 6, characterized in that: The output protection circuit also includes a current limiting circuit; the current limiting circuit includes a resistor R2, a resistor R3 and a resistor R6; one end of the resistor R2 is connected to the base of the transistor Q1, the other end of the resistor R2 is connected to the cathode of the diode D3, one end of the resistor R3 is connected to the collector of the transistor Q1, the other end of the resistor R3 is respectively connected to the anode of the freewheeling diode D4 and pin 1 of the relay JD3, one end of the resistor R6 is connected to the light-emitting diode LED1, and the other end of the resistor R6 is respectively connected to the freewheeling diode D6 and pin 2 of the relay JD1.

8. The power supply device with protection function according to claim 6, characterized in that: The output protection circuit further includes a filter circuit; the filter circuit includes a capacitor C5; one end of the capacitor C5 is connected to the cathode of the diode D3, and the other end of the capacitor C5 is connected to the ground and the power supply circuit respectively.

9. The power supply device with protection function according to claim 6, characterized in that: The relay JD1 includes a driving coil and a contact switch.

10. The power supply device with protection function according to claim 9, characterized in that: The relay JD1 has the same structure as the relay JD2 and the relay JD3.

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