Protection circuit for preventing signal interface from being misconnected with AC power line

Abstract

The utility model relates to a protection circuit for preventing a signal interface from misconnecting an AC power line, which is characterized in that a first end of the signal interface is connected with a first end of a signal output interface through a first relay switch, and a second end of the signal interface is connected with a second end of the signal output interface through a second relay switch; the signal interface, the first relay switch, the signal output interface and the second relay switch form a closed loop; the first end and the second end of the signal interface are also connected with the rectifying circuit; the rectifying circuit is connected with the primary side of the optical coupler; the auxiliary DC power supply is connected with the fourth resistor and the collector of the triode. The fourth resistor is connected with the base electrode of the triode and the input end of the secondary side of the optical coupler. The output end of the secondary side of the optical coupler is grounded. The emitter of the triode is connected with the double-switch normally-open relay; and the double-switch normally-open relay is grounded through a third resistor. According to the utility model, the signal module can be effectively protected, and signal transmission during normal work is not affected.

Description

TECHNICAL FIELD

[0001] The utility model relates to a protection circuit for preventing signal interface from being connected with AC power line by mistake. BACKGROUND

[0002] In some occasions where manual wiring is needed for input interface and the line contains signal line and AC power line, etc., the risk of signal interface being connected with AC power line by mistake often accompanies. Once the line is connected by mistake, the AC mains will break through the low-voltage signal module in an instant, causing economic loss and safety hazard. The traditional method is to do foolproof processing or add identification on the interface to reduce the risk of misconnection, but it cannot provide effective protection for the circuit.

[0003] Therefore, a protection circuit for preventing signal interface from being connected with AC power line by mistake is provided. SUMMARY

[0004] The utility model aims at overcoming the defects of the prior art and providing a protection circuit for preventing signal interface from being connected with AC power line by mistake, which can effectively protect the signal module and will not affect the signal transmission during normal operation.

[0005] The technical scheme for achieving the above-mentioned purpose is as follows:

[0006] A protection circuit for preventing signal interface from being connected with AC power line by mistake, comprising: a signal interface, a signal output interface, a rectifier circuit and an auxiliary DC power supply.

[0007] The first end of the signal interface is connected to the first end of the signal output interface through a first relay switch, and the second end of the signal interface is connected to the second end of the signal output interface through a second relay switch, and the signal interface, the first relay switch, the signal output interface and the second relay switch form a closed loop.

[0008] The first end and the second end of the signal interface are also connected to the rectifier circuit, and the rectifier circuit is connected to the primary side of an optical coupler.

[0009] The auxiliary DC power supply is connected to the fourth resistor and the collector of a triode, respectively.

[0010] The fourth resistor is connected to the base of the triode and the input end of the secondary side of the optical coupler, respectively, and the output end of the secondary side of the optical coupler is grounded.

[0011] The emitter of the triode is connected to a double-switch normally open relay.

[0012] The double-switch normally open relay is grounded through a third resistor.

[0013] Preferably, the rectifier circuit comprises a first resistor, a thin film capacitor and a rectifier bridge.

[0014] The first end of the signal interface is connected with the 2 end of the rectifier bridge through the first resistance and the thin film capacitor;

[0015] The second end of the signal interface is connected with the 3 end of the rectifier bridge;

[0016] The 4 end of the rectifier bridge is grounded;

[0017] The 1 end of the rectifier bridge is connected with the cathode of the first voltage stabilizing diode and the second voltage stabilizing diode respectively;

[0018] The anode of the first voltage stabilizing diode is grounded;

[0019] The anode of the second voltage stabilizing diode is connected with the one end of the electrolytic capacitor and the input end of the primary side of the optical coupler respectively;

[0020] The other end of the electrolytic capacitor is grounded;

[0021] The output end of the primary side of the optical coupler is grounded through the second resistance.

[0022] Preferably, when the signal interface is connected with the signal line, the primary side of the optical coupler has no current, the triode is turned on, the auxiliary DC power supply supplies power for the double-switch normally open relay, the first relay switch and the second relay switch are attracted, and the signal is normally transmitted.

[0023] Preferably, when the signal interface is connected with the AC power line, the AC voltage supplies power for the optical coupler through the rectifier circuit, the secondary side of the optical coupler is turned on, the triode is turned off, the double-switch normally open relay has no current, the first relay switch and the second relay switch remain in the open state, and the signal stops outputting.

[0024] The utility model discloses the beneficial effect is: the utility model discloses the design in the middle of signal interface and signal receiving module, prevent signal receiving module when signal interface misconnects AC power line and damage because of high voltage AC voltage, be applicable to all have the risk of AC power line and signal line mix connection occasion, realize the protection to signal receiving module through the AC voltage of identification signal interface and disconnect the connection of signal interface and signal receiving module, circuit safety and reliability, small loss, and will not affect the normal transmission of signal. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the schematic diagram of the protection circuit of the utility model for preventing signal interface misconnects AC power line. DETAILED DESCRIPTION

[0026] The technical solutions of the utility model will be described clearly and completely below in combination with the drawings. In the description of the utility model, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as a limitation on the utility model that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. In addition, the terms "first", "second" and "third" are only for the purpose of description, and cannot be understood as indicating or implying the importance of the opposite.

[0027] The utility model will be further described below in combination with the drawings.

[0028] As Figure 1 shown, a protection circuit for preventing AC power line from being connected to signal interface in error, comprising: signal interface J1, signal output interface J2, rectifier circuit and auxiliary DC power supply VDD; the first end of signal interface J1 is connected to the first end of signal output interface J2 through first relay switch K1_S1, the second end of signal interface J1 is connected to the second end of signal output interface J2 through second relay switch K1_S2, signal interface J1, first relay switch K1_S1, signal output interface J2 and second relay switch K1_S2 form a closed loop; the first end and the second end of signal interface J1 are also connected to rectifier circuit, and the rectifier circuit is connected to the primary side of photo-coupler U1; auxiliary DC power supply VDD is connected to fourth resistor R4 and the collector of triode Q1 respectively; the base of triode Q1 and the input end of the secondary side of photo-coupler U1 are connected to fourth resistor R4 respectively, and the output end of the secondary side of photo-coupler U1 is grounded; the emitter of triode Q1 is connected to double-switch normally-open relay K1_W; double-switch normally-open relay K1_W is grounded through third resistor R3.

[0029] In the embodiment, the rectifier circuit comprises: first resistor R1, thin film capacitor CBB1 and rectifier bridge BR1, the first end of signal interface J1 is connected to the 2 end of rectifier bridge BR1 through first resistor R1 and thin film capacitor CBB1; the second end of signal interface J1 is connected to the 3 end of rectifier bridge BR1; the 4 end of rectifier bridge BR1 is grounded; the 1 end of rectifier bridge BR1 is connected to the cathode of first zener diode ZD1 and second zener diode ZD2 respectively; the anode of first zener diode ZD1 is grounded; the anode of second zener diode ZD2 is connected to one end of electrolytic capacitor CE1 and the input end of the primary side of photo-coupler U1 respectively; the other end of electrolytic capacitor CE1 is grounded; the output end of the primary side of photo-coupler U1 is grounded through second resistor R2.

[0030] In the embodiment, the current of the rectifier circuit is related to the capacitance of the thin film capacitor CBB1 and the frequency of the AC power supply, because the current is limited by the capacitor, even if the input voltage of the AC power supply is wide, the loss is small; the circuit is safe and reliable, and is suitable for all occasions where the AC power supply line and the signal line are mixed.

[0031] In the embodiment, when the signal interface J1 is connected to the signal line, the primary side of the optocoupler U1 has no current, the transistor Q1 is turned on, the auxiliary DC power supply VDD supplies power to the double-switch normally open relay K1_W, the first relay switch K1_S1 and the second relay switch K1_S2 are attracted, and the signal is normally transmitted and worked.

[0032] In the embodiment, when the signal interface J1 is connected to the AC power supply line, the AC voltage is rectified to supply power to the optocoupler U1, the secondary side of the optocoupler U1 is turned on, the transistor Q1 is turned off, the double-switch normally open relay K1_W has no current, and the first relay switch K1_S1 and the second relay switch K1_S2 remain in the open state, at this time, the signal interface and the rear-end signal receiving module are completely disconnected, thereby realizing the protection of the signal module, until the signal interface J1 is restored to normal, the first relay switch K1_S1 and the second relay switch K1_S2 are attracted.

[0033] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A protection circuit for preventing the connection of an AC power cord to a signal interface, comprising: The utility model relates to a signal interface (J1), signal output interface (J2), rectifier circuit and auxiliary DC power (VDD) are included: The first end of signal interface (J1) is connected with the first end of signal output interface (J2) through the first relay switch (K1_S1), and the second end of signal interface (J1) is connected with the second end of signal output interface (J2) through the second relay switch (K1_S2), and signal interface (J1), the first relay switch (K1_S1), signal output interface (J2) and the second relay switch (K1_S2) form a closed loop, The first end and the second end of signal interface (J1) are also connected with the rectifier circuit, and the rectifier circuit is connected with the primary side of photo-coupler (U1), The auxiliary DC power (VDD) is connected with the fourth resistance (R4) and the collector of triode (Q1) respectively, The fourth resistance (R4) is connected with the base of triode (Q1) and the input end of the secondary side of photo-coupler (U1) respectively, and the output end of the secondary side of photo-coupler (U1) is grounded, The emitter of triode (Q1) is connected with double switch normally open relay (K1_W), And double switch normally open relay (K1_W) is grounded through the third resistance (R3). The rectifier circuit includes: the first resistance (R1), the film capacitor (CBB1) and the rectifier bridge (BR1), 2. The protection circuit according to claim 1, wherein The first end of signal interface (J1) is connected with the 2 end of rectifier bridge (BR1) through the first resistance (R1) and the film capacitor (CBB1), The second end of signal interface (J1) is connected with the 3 end of rectifier bridge (BR1), The 4 end of rectifier bridge (BR1) is grounded, The 1 end of rectifier bridge (BR1) is connected with the cathode of first zener diode (ZD1) and second zener diode (ZD2) respectively, The anode of first zener diode (ZD1) is grounded, The anode of second zener diode (ZD2) is connected with one end of electrolytic capacitor (CE1) and the input end of the primary side of photo-coupler (U1) respectively, The other end of electrolytic capacitor (CE1) is grounded, The output end of the primary side of photo-coupler (U1) is grounded through the second resistance (R2). When the signal interface (J1) is connected with signal line, the primary side of photo-coupler (U1) has no current, triode (Q1) is turned on, the auxiliary DC power (VDD) supplies power for double switch normally open relay (K1_W), the first relay switch (K1_S1) and the second relay switch (K1_S2) are attracted, and signal normal transmission work.

3. The protection circuit for preventing the AC power line from being connected to the signal interface according to claim 1, wherein, When the signal interface (J1) is connected with AC power line, AC voltage supplies power for photo-coupler (U1) through the rectifier circuit, the secondary side of photo-coupler (U1) is turned on, triode (Q1) is closed, double switch normally open relay (K1_W) has no current, the first relay switch (K1_S1) and the second relay switch (K1_S2) keep the state of being disconnected, and signal stops outputting.

4. The protection circuit for preventing the AC power line from being connected to the signal interface according to claim 1, wherein, ​

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