Low-power-consumption surge leakage protection circuit and leakage protector

Abstract

The utility model discloses a surge leakage protection circuit with low power consumption and a leakage protector, a silicon controlled rectifier trigger circuit in the surge leakage protection circuit is directly connected to an alternating current power supply loop, and when a leakage detection circuit detects that leakage current occurs in the alternating current power supply loop, the silicon controlled rectifier trigger circuit is conducted; the tripping circuit is driven to act so as to disconnect the alternating current power supply loop; the current limiting circuit is arranged at the input end of the rectifying circuit, and the step-down circuit is arranged at the output end of the rectifying circuit, so that limitation on large current before rectification and suppression on voltage spike possibly generated in the rectification process after rectification are ensured, and subsequent stable operation of the electric leakage detection circuit is ensured; therefore, the peak suppression circuit is adopted on the alternating current power supply circuit to deal with the 4kV surge design, the single piezoresistor can not only reduce the power consumption of the circuit board to achieve the purpose of energy conservation and improve the working safety of the circuit board, but also reduce the size of the circuit board, and the circuit board can be widely applied to residual current circuit breaker products with limited space.

Description

Technical Field

[0001] The utility model relates to the technical field of leakage protectors, in particular to a low-power surge leakage protection circuit and a leakage protector. Background Art

[0002] A leakage protector, also known as a leakage switch or leakage circuit breaker, is mainly used to protect equipment from leakage faults and to protect people from fatal electric shock.

[0003] The core of a leakage protector's (RCP) protection is its internal RCPC. To prevent the circuit's fluctuating voltage or lightning strikes from affecting and interfering with the RCPC, it's typically equipped with surge protection components. However, conventional full-bridge rectifier RCPCs require a dual varistor combination to withstand a 4kV surge test. This inevitably increases the heat generated by the varistor, leading to increased circuit power consumption and hindering current energy-saving production requirements for RCPCs. Furthermore, the large size of the varistor makes the RCPC with a dual varistor combination difficult to install within the RCPC housing.

[0004] Therefore, it is urgent to design a surge leakage protection circuit that can meet the 4kV surge test and has low power consumption. Summary of the Invention

[0005] In order to solve the above problems, the technical solution provided by the present invention is as follows:

[0006] A low-power surge and leakage protection circuit, comprising a spike suppression circuit, a tripping circuit, a current limiting circuit, a rectification circuit, a voltage reduction circuit, a thyristor trigger circuit, and a leakage detection circuit;

[0007] The peak suppression circuit is connected in parallel at both ends of the AC power supply circuit, the first end of the tripping circuit is connected to the first end of the peak suppression circuit, the first end of the current limiting circuit is connected to the second end of the peak suppression circuit, the second end of the tripping circuit and the second end of the current limiting circuit are respectively connected to the input end of the rectifier circuit, and the input end of the leakage detection circuit detects the leakage current of the AC power supply circuit;

[0008] The two ends of the step-down circuit are respectively connected to the positive output end and the negative output end of the rectifier circuit, the output end of the step-down circuit is connected to the power supply input end of the leakage detection circuit, the first end of the thyristor trigger circuit is connected to the second end of the spike suppression circuit, the second end of the thyristor trigger circuit is connected to the negative output end of the rectifier circuit, and the third end of the thyristor trigger circuit is connected to the output end of the leakage detection circuit.

[0009] The present invention is further configured to include a test circuit, which is connected in parallel at both ends of the AC power supply circuit. The test circuit is used to simulate leakage current and detect whether the leakage circuit breaker can operate normally.

[0010] A leakage protector adopts the above-mentioned low-power surge leakage protection circuit.

[0011] Compared with the prior art, the technical solution provided by this utility model has the following beneficial effects:

[0012] In the surge and leakage protection circuit of this technical solution, the thyristor trigger circuit is directly connected to the AC power supply circuit. When the leakage detection circuit detects leakage current in the AC power supply circuit, the thyristor trigger circuit is turned on to drive the tripping circuit to disconnect the AC power supply circuit. A current limiting circuit is provided at the input end of the rectifier circuit and a step-down circuit is provided at the output end of the rectifier circuit to ensure the limitation of large current before rectification and the suppression of voltage spikes that may be generated in the rectification process after rectification, thereby ensuring the subsequent stable operation of the leakage detection circuit. Based on the layout of the current limiting circuit, the rectifier circuit and the step-down circuit, the design for dealing with 4kV surges on the AC power supply circuit can adopt a spike suppression circuit. The single varistor can not only reduce the power consumption of the circuit board to achieve the purpose of energy saving and improve the working safety of the circuit board, but also reduce the volume of the circuit board, and can be widely used in leakage circuit breaker products with limited space. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a circuit principle block diagram of an embodiment of the utility model.

[0014] Figure 2 This is a circuit diagram of an embodiment of the utility model. DETAILED DESCRIPTION

[0015] In order to further understand the content of the present invention, the present invention is described in detail with reference to the accompanying drawings and embodiments.

[0016] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0017] In the description of the present utility model, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, an integral connection, or a detachable connection; it can be a mechanical connection or an electrical connection, or it can be the internal communication between two components; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0018] Example 1

[0019] Combined with attachment Figure 1 and attached Figure 2 The technical solution of the utility model is a low-power surge and leakage protection circuit, which includes a spike suppression circuit 10, a tripping circuit 20, a current limiting circuit 30, a rectifier circuit 40, a step-down circuit 50, a thyristor trigger circuit 60 and a leakage detection circuit 70;

[0020] The spike suppression circuit 10 is connected in parallel to both ends of the AC power supply circuit (the live wire L and the neutral wire N). The first end of the trip circuit 20 is connected to the first end of the spike suppression circuit 10. The first end of the current limiting circuit 30 is connected to the second end of the spike suppression circuit 10. The second end of the trip circuit 20 and the second end of the current limiting circuit 30 are respectively connected to the input end of the rectifier circuit 40. The input end of the leakage detection circuit 70 detects the leakage current of the AC power supply circuit.

[0021] The two ends of the step-down circuit 50 are respectively connected to the positive output end and the negative output end of the rectifier circuit 40, the output end of the step-down circuit 50 is connected to the power supply input end of the leakage detection circuit 70, the first end of the thyristor trigger circuit 60 is connected to the second end of the spike suppression circuit 10, the second end of the thyristor trigger circuit 60 is connected to the negative output end of the rectifier circuit 40, and the third end of the thyristor trigger circuit 60 is connected to the output end of the leakage detection circuit 70.

[0022] In the above embodiment, the rectifier circuit 40 is a full-bridge rectifier, and the thyristor trigger circuit 60 uses thyristor components.

[0023] In this embodiment, the spike suppression circuit 10 includes a varistor RV1, the current limiting circuit 30 includes a resistor R2, the step-down circuit 50 includes a resistor R3 and a capacitor C1, the rectifier circuit 40 is a rectifier bridge U2, and the tripping circuit 20 includes a tripping coil T1 and a tripper;

[0024] The two ends of the varistor RV1 are respectively connected to the two ends of the AC power supply circuit (the live wire L and the neutral wire N), the first end of the varistor RV1 is connected to the first end of the trip coil T1, the second end of the varistor RV1 is connected to the first end of the resistor R2, the second end of the trip coil T1 and the second end of the resistor R2 are respectively connected to the input end of the rectifier bridge U2, the trip device is located at the incoming end of the AC power supply circuit, the trip coil T1 is connected to the trip device in a linkage manner, the first end of the resistor R3 is connected to the positive output end of the rectifier bridge U2, the second end of the resistor R3 is connected to the first end of the capacitor C1, and the second end of the capacitor C1 is connected to the negative output end of the rectifier bridge U2.

[0025] In the above embodiment, when DC power is supplied to the tripping coil T1 , the tripping device is driven to operate so as to disconnect the AC power supply circuit.

[0026] In the above embodiment, the step-down circuit 50 is composed of a resistor R3 and a capacitor C1 connected in series. The principle that the voltage of the capacitor C1 cannot change suddenly is determined by the volt-ampere characteristic of the capacitor C1 to prevent voltage spikes caused by voltage fluctuations on the input side of the AC power supply circuit. The resistor R3 is used to suppress the generation of current spikes, thereby reducing the number of surge components at the input end of the rectifier bridge U2.

[0027] In the above embodiment, the model of the rectifier bridge U2 is MB10F.

[0028] In this embodiment, the thyristor trigger circuit 60 includes a thyristor SCR1, the anode of the thyristor SCR1 is connected to the second end of the varistor RV1, the cathode of the thyristor SCR1 is connected to the negative output end of the rectifier bridge U2, and the gate of the thyristor SCR1 is connected to the output end of the leakage detection circuit 70.

[0029] In this embodiment, the leakage detection circuit 70 includes a leakage protection chip U1, capacitors C1 to C7, resistors R4 to R6, a switching diode D1, and a leakage detection magnetic ring M1. The AC power supply circuit is inserted into the leakage detection magnetic ring M1. A detection winding is wound around the leakage detection magnetic ring M1. The resistor R6, the capacitor C8, and the switching diode D1 are all connected in parallel to the two ends of the detection winding. The first end of the detection winding is connected to the first end of the resistor R4, and the second end of the detection winding is connected to the first end of the resistor R5. The second end of the resistor R4 is respectively connected to the first end of the capacitor C7, the first end of the capacitor C6, and the first pin of the leakage protection chip U1. The second end of the resistor R5 is respectively connected to the second end of the capacitor C7. , the second pin of the leakage protection chip U1 and the first end of the capacitor C5, the first end of the capacitor C4 is respectively connected to the fourth pin of the leakage protection chip U1 and the fifth pin of the leakage protection chip U1, the second end of the capacitor C6, the second end of the capacitor C5, the second end of the capacitor C4 and the third pin of the leakage protection chip U1 are connected to a common ground, the sixth pin of the leakage protection chip U1 is connected to the first end of the capacitor C3, the second end of the capacitor C3, the seventh pin of the leakage protection chip U1 and the first end of the capacitor C2 are all connected to the gate of the thyristor SCR1, the second end of the capacitor C2 is connected to the negative output end of the rectifier bridge U2, and the eighth pin of the leakage protection chip U1 is connected to the second end of the resistor R3.

[0030] In this embodiment, the model of the leakage protection chip U1 is M54123L.

[0031] In this embodiment, the model of the switching diode D1 is BAV99.

[0032] In this embodiment, a test circuit 80 is further included. The test circuit 80 includes a test button S1 and a resistor R1 connected in series. One end of the test button S1 is connected to the second end of the spike suppression circuit 10, and the first end of the resistor R1 is connected to the second end of the trip coil T1.

[0033] In this embodiment, the resistance of the resistor R2 is 47K ohms to 100K ohms, preferably, the resistance of the resistor R2 is 68K; the resistance of the resistor R3 is 22K ohms to 47K ohms, preferably, the resistance of the resistor R3 is 33K; the value range of the capacitor C1 is 100nF to 4.7μF, preferably, the value of the capacitor C1 is 1μF.

[0034] Example 2

[0035] The technical solution of the utility model is a leakage protector, which adopts the low-power surge leakage protection circuit described in Example 1.

[0036] In this embodiment, the leakage protector is suitable for a voltage circuit with an AC frequency of 50 Hz and a rated voltage of 380 volts or less.

[0037] The above is a schematic description of the present invention and its embodiments, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by this and, without departing from the inventive purpose of the present invention, designs a structure and embodiment similar to the technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. A low-power surge and leakage protection circuit, characterized in that: Including spike suppression circuit, tripping circuit, current limiting circuit, rectification circuit, step-down circuit, thyristor trigger circuit and leakage detection circuit; The peak suppression circuit is connected in parallel at both ends of the AC power supply circuit, the first end of the tripping circuit is connected to the first end of the peak suppression circuit, the first end of the current limiting circuit is connected to the second end of the peak suppression circuit, the second end of the tripping circuit and the second end of the current limiting circuit are respectively connected to the input end of the rectifier circuit, and the input end of the leakage detection circuit detects the leakage current of the AC power supply circuit; The two ends of the step-down circuit are respectively connected to the positive output end and the negative output end of the rectifier circuit, the output end of the step-down circuit is connected to the power supply input end of the leakage detection circuit, the first end of the thyristor trigger circuit is connected to the second end of the spike suppression circuit, the second end of the thyristor trigger circuit is connected to the negative output end of the rectifier circuit, and the third end of the thyristor trigger circuit is connected to the output end of the leakage detection circuit.

2. A low-power surge and leakage protection circuit according to claim 1, characterized in that: The spike suppression circuit includes a varistor RV1, the current limiting circuit includes a resistor R2, the voltage step-down circuit includes a resistor R3 and a capacitor C1, the rectifier circuit is a rectifier bridge U2, and the tripping circuit includes a tripping coil T1 and a tripper; The two ends of the varistor RV1 are respectively connected to the two ends of the AC power supply circuit, the first end of the varistor RV1 is connected to the first end of the trip coil T1, the second end of the varistor RV1 is connected to the first end of the resistor R2, the second end of the trip coil T1 and the second end of the resistor R2 are respectively connected to the input end of the rectifier bridge U2, the trip device is located at the incoming end of the AC power supply circuit, the trip coil T1 is connected to the trip device in a linkage manner, the first end of the resistor R3 is connected to the positive output end of the rectifier bridge U2, the second end of the resistor R3 is connected to the first end of the capacitor C1, and the second end of the capacitor C1 is connected to the negative output end of the rectifier bridge U2.

3. A low-power surge and leakage protection circuit according to claim 2, characterized in that: The thyristor trigger circuit includes a thyristor SCR1, the anode of the thyristor SCR1 is connected to the second end of the varistor RV1, the cathode of the thyristor SCR1 is connected to the negative output end of the rectifier bridge U2, and the gate of the thyristor SCR1 is connected to the output end of the leakage detection circuit.

4. A low-power surge and leakage protection circuit according to claim 3, characterized in that: The leakage detection circuit includes a leakage protection chip U1, capacitors C1 to C7, resistors R4 to R6, a switching diode D1 and a leakage detection magnetic ring M1. The AC power supply circuit is inserted into the leakage detection magnetic ring M1. A detection winding is wound around the leakage detection magnetic ring M1. The resistor R6, the capacitor C8 and the switching diode D1 are all connected in parallel to the two ends of the detection winding. The first end of the detection winding is connected to the first end of the resistor R4, and the second end of the detection winding is connected to the first end of the resistor R5. The second end of the resistor R4 is respectively connected to the first end of the capacitor C7, the first end of the capacitor C6 and the first pin of the leakage protection chip U1. The second end of the resistor R5 is respectively connected to the second end of the capacitor C7, the leakage The second pin of the leakage protection chip U1 and the first end of the capacitor C5, the first end of the capacitor C4 are respectively connected to the fourth pin of the leakage protection chip U1 and the fifth pin of the leakage protection chip U1, the second end of the capacitor C6, the second end of the capacitor C5, the second end of the capacitor C4 and the third pin of the leakage protection chip U1 are connected to a common ground, the sixth pin of the leakage protection chip U1 is connected to the first end of the capacitor C3, the second end of the capacitor C3, the seventh pin of the leakage protection chip U1 and the first end of the capacitor C2 are all connected to the gate of the thyristor SCR1, the second end of the capacitor C2 is connected to the negative output end of the rectifier bridge U2, and the eighth pin of the leakage protection chip U1 is connected to the second end of the resistor R3.

5. A low-power surge and leakage protection circuit according to claim 4, characterized in that: The model of the leakage protection chip U1 is M54123L.

6. The low-power surge and leakage protection circuit according to claim 4, characterized in that: The model of the switching diode D1 is BAV99.

7. A low-power surge and leakage protection circuit according to any one of claims 2 to 6, characterized in that: It also includes a test circuit, which includes a test button S1 and a resistor R1 connected in series, one end of the test button S1 is connected to the second end of the spike suppression circuit, and the first end of the resistor R1 is connected to the second end of the trip coil T1.

8. A low-power surge and leakage protection circuit according to any one of claims 2 to 6, characterized in that: The resistance value of the resistor R2 is 47K ohms to 100K ohms, the resistance value of the resistor R3 is 22K ohms to 47K ohms, and the value range of the capacitor C1 is 100nF to 4.7μF.

9. A leakage protector, characterized in that: A low-power surge and leakage protection circuit according to any one of claims 1 to 8 is used.

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