Output socket short circuit detection circuit

Abstract

The utility model relates to the technical field of short circuit detection, in particular to an output socket short circuit detection circuit. Comprising a load interface piece, a control module and an optical coupler U1, when the load interface piece is connected with a load, base voltages of two transistors are clamped through different loads accessed to a triode Q1 branch circuit, so that the working state of a triode Q2 is changed to control the optical coupler U1 to work, and therefore, the control module judges whether an output socket is short-circuited or not; therefore, the device can automatically identify whether the output port load is short-circuited, improves the safety and reliability of equipment, and reduces the operation and maintenance cost. According to the utility model, before equipment output, the equipment can automatically detect whether the load is short-circuited and judge whether normal output is needed, thereby reducing the operation and maintenance cost and improving the safety and reliability of the equipment.

Description

Technical Field

[0001] The utility model relates to the technical field of short - circuit detection, and particularly to a short - circuit detection circuit for an output socket. Background Art

[0002] At present, the short - circuit protection function of sockets is mainly realized by air switches and fuses. The main principle is that when a short - circuit occurs in the load, the current in the loop will suddenly increase, exceeding the rated current of the air switch and fuse, causing the protection device to act and disconnect its short - circuit loop, thereby realizing the protection function. The main problem with using air switches and fuses for short - circuit protection is the excessively high operation and maintenance cost. If a short - circuit occurs, maintenance personnel are now required to manually push the air switch and replace the fuse on - site. Moreover, this solution cannot determine whether the load is short - circuited before the load is powered on, and there is a chance that the device will burn out instantly at the moment of short - circuit.

[0003] In view of this, the utility model provides a short - circuit detection circuit for an output socket. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a short - circuit detection circuit for an output socket in view of the deficiencies of the prior art.

[0005] To solve the above - mentioned technical problems, the following technical solutions are adopted:

[0006] The short - circuit detection circuit for an output socket includes a load interface component, a control module, and an optocoupler U1.

[0007] One end of the optocoupler U1 is connected to a resistor R1. The resistor R1 is connected to the negative electrode of a diode D1, and the positive electrode of the diode D1 is connected to the AC live wire.

[0008] One end of the optocoupler U1 is connected to the positive electrode of a diode D2. The negative electrode of the diode D2 is connected to the collector of a triode Q1. The emitter of the triode Q1 is connected to the positive electrode of a diode D3. The negative electrode of the diode D3 is connected to the live - wire interface end of the load interface component. The base of the triode Q1 is respectively connected in parallel to a resistor R2 and the base of a triode Q2, and the resistor R2 is connected to the AC live wire.

[0009] The second end of the optocoupler U1 is connected to the collector of a triode Q. The base of the triode Q is connected to a resistor R2. The emitter of the triode Q is connected to a resistor R3. The resistor R3 is connected to the positive electrode of a diode D4. The negative electrode of the diode D4 is respectively connected in parallel to the AC neutral wire and the neutral - wire interface end of the load interface component.

[0010] The fourth end of the optocoupler U1 is connected to the control module.

[0011] On the basis of the above technical solution, a further improvement is that the control module is a single-chip microcomputer control module.

[0012] On the basis of the above technical solution, a further improvement is that the 4th terminal of the optocoupler U1 is connected to a resistor R4, the other end of the resistor R4 is connected to the voltage VDD, and the 3rd terminal of the optocoupler U1 is grounded.

[0013] On the basis of the above technical solution, a further improvement is that the load interface part is a socket load interface part or a plug load interface part.

[0014] Due to the adoption of the above technical solution, the following beneficial effects are achieved:

[0015] By providing an output socket short-circuit detection circuit, when the load interface part is connected to a load, different loads are accessed through the triode Q1 branch, the base voltages of the two transistors are clamped, and the working state of the triode Q2 is changed to control the operation of the optocoupler U1, so that the control module can judge whether the output socket is short-circuited. Therefore, the present utility model can automatically identify whether the output port load is short-circuited, improve the safety and reliability of the device, and reduce the operation and maintenance cost.

[0016] The present utility model can self-check whether the load is short-circuited before the device outputs, judge whether normal output is required, reduce the operation and maintenance cost, and improve the safety and reliability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present utility model will be further described below with reference to the drawings:

[0018] Figure 1 is the circuit diagram of the output socket short-circuit detection circuit of the embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] In order to make the purpose, technical solution and advantages of the present utility model clearer, the present utility model will be further described in detail below through the drawings and embodiments. However, it should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the scope of the present utility model. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessarily confusing the concept of the present utility model.

[0020] Refer to Figure 1 , the output socket short-circuit detection circuit includes a load interface part, a control module and an optocoupler U1.

[0021] The 1st terminal of the optocoupler U1 is connected to a resistor R1, the resistor R1 is connected to the negative electrode of a diode D1, and the positive electrode of the diode D1 is connected to the AC live wire.

[0022] One end of the optocoupler U1 is connected to the positive electrode of the diode D2. The negative electrode of the diode D2 is connected to the collector of the triode Q1. The emitter of the triode Q1 is connected to the positive electrode of the diode D3. The negative electrode of the diode D3 is connected to the live wire interface end of the load interface component. The base of the triode Q1 is respectively connected in parallel to the base of the resistor R2 and the triode Q2. The resistor R2 is connected to the AC live wire.

[0023] One end of the optocoupler U1 is connected to the collector of the triode Q. The base of the triode Q is connected to the resistor R2. The emitter of the triode Q is connected to the resistor R3. The resistor R3 is connected to the positive electrode of the diode D4. The negative electrode of the diode D4 is respectively connected in parallel to the AC neutral wire and the neutral wire interface end of the load interface component.

[0024] One end of the optocoupler U1 is connected to the control module.

[0025] The above-mentioned AC live wire and AC neutral wire can be normal 220V AC power.

[0026] As a further description of this embodiment, the control module is a single-chip microcomputer control module.

[0027] As a further description of this embodiment, one end of the optocoupler U1 is connected to the resistor R4. The other end of the resistor R4 is connected to the voltage VDD. One end of the optocoupler U1 is grounded.

[0028] As a further description of this embodiment, the load interface component is a socket load interface component or a plug load interface component.

[0029] The detection steps of the present utility model are as follows:

[0030] 1. On the two branches of diode D2 → triode Q1 → diode D3 and optocoupler U1 → triode Q2 → diode D4, the input end of the optocoupler U1 is approximately equal to the diode D2, making the parameters of the two branches equal and constituting a comparison circuit of R3 and the load. Among them, the value of R3 can be adjusted according to actual requirements.

[0031] 2. When 220V mains power is applied to the live wire and neutral wire of the device, when the AC power is in the positive half cycle, the triode Q1 and the triode Q2 are turned on, and the secondary of the optocoupler U1 outputs pulsating direct current.

[0032] 3. In the two loops of live wire → resistor R2 → base (BE) of triode Q1 → diode D3 → load → neutral wire and live wire → resistor R2 → base (BE) of triode Q2 → resistor R3 → diode D4 → neutral wire, the base (BE) of triode Q1 → diode D3 → load and the base (BE) of triode Q2 → resistor R3 → diode D4 are in a parallel relationship.

[0033] 4. When no load is connected, the current at the input end of the optocoupler U1 is the largest, and at this time, the conduction ability of the optocoupler U1 is the strongest.

[0034] 5. When a load is connected and the resistance value of the connected load decreases, the total impedance of the parallel circuit of the base (BE) of the triode Q1 → diode D3 → load and the base (BE) of the triode Q2 → resistor R3 → diode D4 decreases, the voltage across the resistor R2 increases, and the voltage across the branch of the base (BE) of the triode Q2 → resistor R3 → diode D4 decreases, causing the Ib of the triode Q2 to decrease and its Ic to also decrease.

[0035] 6. The current at the input end of the optocoupler U1 is equal to the Ic of the triode Q2. When the Ic of Q2 decreases, the conduction ability of the optocoupler U1 also weakens accordingly.

[0036] 7. Insert a load equal to the resistance value of R3 into the load interface, and adjust the size of R4 to make the minimum value of the pulsating direct current output by the secondary of the optocoupler U1 the maximum value that can be recognized as a low level by the single-chip microcomputer.

[0037] 8. When the output load is less than the resistor R3 or is short-circuited, the minimum value of the pulsating direct current output by the secondary of the optocoupler U1 is greater than the set value, causing the single-chip microcomputer to be unable to receive a low level, judging that the output socket is short-circuited, and making the load unable to work, thus realizing the short-circuit protection of the device.

[0038] The utility model changes the conduction current of the optocoupler U1, reduces its conduction ability, and raises the voltage drop at the secondary, so as to realize the self-check of the short circuit of the load at the device socket. If the self-check shows that the output socket is short-circuited, the device will not output, thereby realizing the short-circuit protection of the device.

[0039] The above are only specific embodiments of the utility model, but the technical features of the utility model are not limited thereto. Any simple changes, equivalent replacements, or modifications made based on the utility model to solve basically the same technical problems and achieve basically the same technical effects are all covered by the protection scope of the utility model.

Claims

1. Output socket short circuit detection circuit, characterized in that: Including load interface, control module and optocoupler U1, One end of the optical coupler U1 is connected to a resistor R1, the resistor R1 is connected to the cathode of a diode D1, and the anode of the diode D1 is connected to the AC live wire; One end of the optical coupler U1 is connected to the positive electrode of the diode D2, the negative electrode of the diode D2 is connected to the collector of the transistor Q1, the emitter of the transistor Q1 is connected to the positive electrode of the diode D3, the negative electrode of the diode D3 is connected to the live wire interface end of the load interface component, the base of the transistor Q1 is respectively connected in parallel with the resistor R2 and the base of the transistor Q2, and the resistor R2 is connected to the live wire of the AC power; Two ends of the optical coupler U1 are connected to the collector of the transistor Q, the base of the transistor Q is connected to the resistor R2, the emitter of the transistor Q is connected to the resistor R3, the resistor R3 is connected to the positive electrode of the diode D4, and the negative electrode of the diode D4 is connected in parallel to the neutral line of the AC power and the neutral line interface terminal of the load interface component; The four ends of the optical coupler U1 are connected to a control module.

2. The output socket short circuit detection circuit according to claim 1, characterized in that: The control module is a single chip microcomputer control module.

3. The output socket short circuit detection circuit according to claim 1, characterized in that: The 4th terminal of the optical coupler U1 is connected to a resistor R4, the other end of the resistor R4 is connected to a voltage VDD, and the 3rd terminal of the optical coupler U1 is grounded.

4. The output socket short circuit detection circuit according to claim 1, characterized in that: The load interface is a socket load interface or a plug load interface.

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