CN217087493U

CN217087493U - Leakage protection circuit

Info

Publication number: CN217087493U
Application number: CN202123047845.0U
Authority: CN
Inventors: 吴瑞勋; 龚峰
Original assignee: Hangzhou Youwang Electronics Co ltd
Current assignee: Hangzhou Youwang Electronics Co ltd
Priority date: 2021-12-06
Filing date: 2021-12-06
Publication date: 2022-07-29
Anticipated expiration: 2031-12-06

Abstract

Disclosed is a leakage protection circuit including: the rectification module is used for rectifying an alternating current signal generated by the alternating current circuit and outputting a rectified signal; the induction module is coupled with the alternating current main line and generates a trigger signal according to the change of the magnetic flux at the coupling part; the voltage detection module receives the rectification signal, detects the power grid voltage on the alternating current main line and compares the power grid voltage with a protection threshold value to generate a voltage detection signal; the leakage protection chip is connected with the induction module and the voltage detection module, receives the trigger signal and the voltage detection signal, and generates a conduction signal according to the trigger signal and the voltage detection signal; the tripping protection module is respectively connected with the alternating current main line and the leakage protection chip and used for disconnecting the power supply connection of the alternating current main line according to the conduction signal, the leakage protection circuit can detect the voltage in the circuit, and can cut off the power supply in time when an overvoltage or undervoltage condition occurs, so that the circuit and personal safety are ensured, the structure is simple, and the reliability is high.

Description

Leakage protection circuit

Technical Field

The utility model relates to a power electronics field of relevance, specificly relate to an earth leakage protection circuit.

Background

The appliance leakage protection circuit breaker (ALCI) has the leakage protection function and can effectively prevent the human body from electric shock and fire accidents, thereby being widely applied to household appliances. Circuit breakers are typically connected between a power source and a load to protect the load.

At present, most of common small-sized leakage protection circuit breakers in the market do not have the overvoltage and undervoltage protection function. That is, when the voltage exceeds a certain threshold or is far below a certain threshold, the breaker cannot be found in time. Specifically, in some situations where overvoltage and undervoltage protection is required, for example, when the load is a motor and the power supply is under-voltage, if the circuit breaker cannot be timely found and tripped out for protection, the motor may be burned out due to the temperature rise of the motor, which may cause a safety hazard. And the leakage protection chip of the circuit breaker is provided with a power supply overvoltage and undervoltage protection circuit, so that the corresponding protection function can be realized only by arranging more peripheral devices, which is more tedious and has higher cost.

SUMMERY OF THE UTILITY MODEL

In view of the above, an object of the present invention is to provide a leakage protection circuit based on circuit breaker, which can adopt fewer simple components to configure an under-voltage protection circuit for the circuit breaker, thereby realizing the under-voltage protection function, the circuit implementation cost is low, the reliability is high, the chip power supply can be quickly realized, the under-voltage protection can be realized, and the problem that the leakage protection system does not have the power supply under-voltage protection function in the prior art can be solved.

According to the utility model provides an earth leakage protection circuit, include:

the rectification module is used for rectifying an alternating current signal generated by the alternating current circuit and outputting a rectified signal;

the induction module is coupled with the alternating current main line and generates a trigger signal according to the change of the magnetic flux at the coupling part;

the voltage detection module receives the rectification signal, detects the power grid voltage on the alternating current main line and compares the power grid voltage with a protection threshold value to generate a voltage detection signal;

the leakage protection chip is connected with the induction module and the voltage detection module, receives the trigger signal and the voltage detection signal and generates a conduction signal according to the trigger signal and the voltage detection signal; and

and the tripping protection module is respectively connected with the alternating current trunk line and the leakage protection chip and used for disconnecting the power supply connection of the alternating current trunk line according to the conduction signal.

Optionally, the leakage protection circuit further comprises:

and the power supply module is connected with the rectifying module and the electric leakage protection chip and is used for providing the rectified alternating current signal to the electric leakage protection chip.

Optionally, the leakage protection circuit further comprises:

and the self-checking module is connected to the alternating current main line and used for changing the magnetic flux at the coupling position of the induction module and the alternating current main line according to external control so as to control the induction module to generate a trigger signal.

Optionally, the voltage detection module includes an overvoltage detection module, when the grid voltage on the ac main line is greater than an overvoltage protection threshold, the voltage detection signal is an overvoltage detection signal, and the leakage protection chip controls the trip protection module to disconnect the power connection of the ac main line according to the overvoltage detection signal.

Optionally, the voltage detection module includes an under-voltage detection module, when the grid voltage on the ac main line is smaller than an under-voltage protection threshold, the voltage detection signal is an under-voltage detection signal, and the leakage protection chip controls the trip protection module to disconnect the power supply connection of the ac main line according to the under-voltage detection signal.

Optionally, the voltage detection module includes an overvoltage detection module and an undervoltage detection module, and when a grid voltage on the ac main line is greater than an overvoltage protection threshold and the grid voltage on the ac main line is less than an undervoltage protection threshold, the leakage protection chip controls the trip protection module to disconnect the power connection of the ac main line according to the voltage detection signal.

Optionally, the overvoltage detection module comprises: the overvoltage protection device comprises a voltage dividing module, a voltage dividing voltage filtering module, an overvoltage sampling module and a sampling voltage filtering module, wherein the voltage dividing voltage filtering module is right for filtering the divided voltage of the voltage dividing module, the sampling voltage filtering module is right for filtering the voltage sampled by the overvoltage sampling module, and the overvoltage sampling module is right for sampling the voltage of the voltage dividing module and outputting an overvoltage detection signal to the leakage protection chip.

Optionally, the brown-out detection module includes: partial pressure module, partial pressure voltage filter module, undervoltage sampling trigger module, undervoltage sampling module and sampling voltage filter module, partial pressure voltage filter module is right the voltage that partial pressure module divides is filtered, sampling voltage filter module is right the voltage of undervoltage sampling module sampling filters, zener diode in the undervoltage sampling trigger module is in grid voltage is less than do not switch on when the undervoltage protection threshold value, triggers the control termination ground of the transistor in the undervoltage sampling module switches on, the second end of transistor to the undervoltage detection signal of earth leakage protection chip output.

Optionally, the voltage detection module includes a voltage division module, a voltage division voltage filtering module, an overvoltage sampling module, a sampling voltage filtering module, an undervoltage sampling trigger module, and an undervoltage sampling module, where the voltage division voltage filtering module filters the voltage divided by the voltage division module, the sampling voltage filtering module filters the voltage sampled by the overvoltage sampling module or the undervoltage sampling module, the overvoltage sampling module samples the voltage of the voltage division module, and a cathode of a second diode in the overvoltage sampling module outputs an overvoltage detection signal to the leakage protection chip; and when the voltage of the power grid is smaller than the undervoltage protection threshold value, a voltage stabilizing diode in the undervoltage sampling trigger module is not conducted, so that the control end of a transistor in the undervoltage sampling module is triggered to be conducted in a grounded mode, and the second end of the transistor outputs an undervoltage detection signal to the leakage protection chip.

Optionally, in the overvoltage detection module, the voltage dividing module includes a first resistor, a second resistor, a third resistor, and a fourth resistor, the divided voltage filtering module includes a first capacitor, the sampled voltage filtering module includes a second capacitor, the overvoltage sampling module includes a second diode and a seventh resistor, wherein,

the first resistor to the fourth resistor are sequentially connected in series between a live wire and ground of the alternating current main line;

the first end of the first capacitor is connected between the first resistor and the second resistor, and the second end of the first capacitor is grounded;

a first end of the seventh resistor is connected between the third resistor and the fourth resistor, a second end of the seventh resistor is connected with an anode of the second diode, and a cathode of the second diode is grounded;

the first end of the second capacitor is connected with the cathode of the second diode, the second end is grounded,

the overvoltage sampling module samples the voltage of the first end of the fourth resistor, and the cathode of a second diode in the overvoltage sampling module outputs an overvoltage detection signal to the leakage protection chip.

Optionally, in the under-voltage detection module, the voltage dividing module includes a first resistor, a second resistor, a third resistor, and a fourth resistor, the voltage dividing and filtering module includes a first capacitor, the under-voltage sampling and triggering module includes a fifth resistor, a zener diode, an eighth resistor, and a ninth resistor, the under-voltage sampling module includes a sixth resistor and a transistor, the sampling voltage filtering module includes a second capacitor,

the first end of the fifth resistor is connected between the first resistor and the second resistor, and the second end of the fifth resistor is connected with the cathode of the voltage stabilizing diode;

the first end of the eighth resistor is connected with the second end of the first capacitor, and the second end of the eighth resistor is connected with the anode of the voltage stabilizing diode;

a first end of the ninth resistor is connected with the anode of the voltage stabilizing diode, and a second end of the ninth resistor is connected with the control end of the transistor;

a first end of the sixth resistor is connected between the second resistor and the third resistor, and a second end of the sixth resistor is connected with the first end of the transistor;

the first end of the second capacitor is connected with the second end of the transistor, the second end is grounded,

and the voltage stabilizing diode in the undervoltage sampling trigger module is not conducted when the power grid voltage is smaller than the undervoltage protection threshold value, the control end of the transistor in the undervoltage sampling trigger module is triggered to be conducted, and the second end of the transistor outputs an undervoltage detection signal to the leakage protection chip.

Optionally, in the voltage detection module, the voltage dividing module includes a first resistor, a second resistor, a third resistor, and a fourth resistor, the voltage dividing and filtering module includes a first capacitor, the sampling voltage filtering module includes a second capacitor, the overvoltage sampling module includes a second diode and a seventh resistor, the undervoltage sampling trigger module includes a fifth resistor, a zener diode, an eighth resistor, and a ninth resistor, the undervoltage sampling module includes a sixth resistor and a transistor, wherein,

a first end of the sixth resistor is connected between the second resistor and the third resistor, and a second end of the sixth resistor is connected with a first end of the transistor;

a first end of the seventh resistor is connected between the third resistor and the fourth resistor, a second end of the seventh resistor is connected with an anode of the second diode, and a cathode of the second diode is connected with a second end of the transistor;

the overvoltage sampling module samples the voltage of the first end of the fourth resistor, and the cathode of a second diode in the overvoltage sampling module outputs an overvoltage detection signal to the leakage protection chip; and the voltage stabilizing diode in the undervoltage sampling trigger module is not conducted when the power grid voltage is smaller than the undervoltage protection threshold value, the control end of the transistor in the undervoltage sampling trigger module is triggered to be conducted, and the second end of the transistor outputs an undervoltage detection signal to the leakage protection chip.

Optionally, the rectifier module comprises:

and the anode of the first diode is connected with the live wire, and the cathode of the first diode is connected with the power supply module and the voltage detection module.

Optionally, the sensing module comprises:

the transformer is coupled on the AC trunk line and comprises a first output end and a second output end;

the two ends of the tenth resistor are respectively connected with the first output end and the second output end of the mutual inductor;

the third capacitor is connected in parallel with the tenth resistor and is connected between the first output end and the second output end of the mutual inductor;

a first end of the fourth capacitor is connected with the first output end of the mutual inductor;

the first end of the eleventh resistor is connected with the second output end of the mutual inductor, and the second end of the eleventh resistor is connected with the second end of the fourth capacitor; and

and the first end of the fifth capacitor is connected with the first end of the fourth capacitor, and the second end of the fifth capacitor is grounded.

Optionally, the trip protection module includes:

a solenoid having a first end connected to the hot line of the ac mains for disconnecting or making a power connection to the ac mains;

a first diode having an anode connected to a second terminal of the solenoid, the first diode being configured to rectify an ac signal to generate a rectified signal;

the first end of the controlled silicon is connected to the cathode of the first diode, the second end of the controlled silicon is grounded, and the control electrode of the controlled silicon is connected to the leakage protection chip and used for receiving the conducting signal;

the third diode is connected between the leakage protection chip and the control electrode of the controllable silicon, and the cathode of the third diode is connected with the control electrode of the controllable silicon;

the first end of the eighth capacitor is connected to the cathode of the third diode, and the second end of the eighth capacitor is grounded; and

and the twelfth resistor is connected with the eighth capacitor in parallel.

Optionally, the earth leakage protection chip comprises a first pin to an eighth pin, wherein,

a first pin is connected to a first end of the fourth capacitor,

a second pin is connected to a second end of the fourth capacitor, and the first pin and the second pin are used for receiving the trigger signal;

the third pin is grounded;

the fourth pin is connected to the fifth pin,

the fifth pin is connected to the ground terminal through a seventh capacitor;

the sixth pin is connected to the voltage detection module and used for receiving the voltage detection signal;

the seventh pin is connected with the anode of the third diode and used for outputting a conduction signal of the Silicon Controlled Rectifier (SCR) according to the voltage detection signal;

the eighth pin is connected to the power module and receives a supply voltage.

Optionally, the voltage detection module includes an overvoltage detection module and an undervoltage detection module, when the grid voltage on the ac main line is greater than an overvoltage protection threshold, the voltage detection signal is an overvoltage detection signal, when the grid voltage on the ac main line is less than the undervoltage protection threshold, the voltage detection signal is an undervoltage detection signal, the sixth pin of the leakage protection chip receives the overvoltage detection signal output by the overvoltage detection module and the undervoltage detection signal output by the undervoltage detection module, compares the overvoltage detection signal and the undervoltage detection signal with a saturation voltage drop of the sixth pin of the leakage protection chip, and outputs a turn-on signal through the seventh pin of the leakage protection chip to drive the trip protection module to disconnect the power supply connection of the ac main line.

Optionally, the power module comprises:

a thirteenth resistor, wherein a first end of the thirteenth resistor is connected to the cathode of the first diode, and a second end of the thirteenth resistor is connected to the eighth pin of the leakage protection chip;

and a first end of the sixth capacitor is connected with the second end of the thirteenth resistor, and the second end of the sixth capacitor is grounded.

Optionally, during a positive half cycle of the alternating current signal, the voltage detection module and the induction module operate simultaneously.

Optionally, the leakage protection circuit further comprises a piezoresistor, wherein the piezoresistor is connected between a zero line and a live line of the alternating current main line and forms lightning surge resistance to the leakage protection circuit.

The utility model discloses earth leakage protection circuit has set up voltage detection module in the circuit breaker, can detect alternating current circuit's mains voltage, when mains voltage surpassed or was less than the protection threshold value, send voltage detection signal to the detection pin of the earth leakage protection chip of circuit breaker, earth leakage protection chip receives this voltage detection signal and by another pin output control signal, the control silicon controlled rectifier switches on to connect through the power of dropout protection module disconnection alternating current circuit, play the guard action to circuit and follow-up load. The leakage protection circuit adopts simple elements to realize the over-voltage and under-voltage protection function, can quickly realize the over-voltage and under-voltage protection of the chip, protects the personal safety of a user, improves the working efficiency of the circuit breaker, reduces the manufacturing cost and has high circuit reliability.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.

Fig. 1 shows a schematic circuit diagram of a prior art circuit breaker.

Fig. 2 shows a schematic block diagram of a leakage protection circuit according to an embodiment of the present invention.

Fig. 3 shows a schematic block diagram of a leakage protection circuit according to an embodiment of the invention connected to an ac mains.

Fig. 4 shows a schematic circuit diagram of a leakage protection circuit according to a first embodiment of the present invention.

Fig. 5 shows a schematic circuit diagram of a leakage protection circuit according to a second embodiment of the present invention.

Fig. 6 shows a schematic circuit diagram of a leakage protection circuit according to a third embodiment of the present invention.

Detailed Description

Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.

Fig. 1 shows a schematic circuit diagram of a prior art circuit breaker. As shown in fig. 1, an induction coil N1 is coupled to the live line L and the neutral line N, an outgoing line of the induction coil N1 is connected to the leakage protection module 10, the leakage protection module 10 includes a leakage protection chip, and the induction coil N1 is configured to input a leakage signal to the leakage protection module 10. The earth leakage protection module 10 is connected to the control end of a thyristor SQ, the anode of the thyristor SQ is connected with the first end of a solenoid L1, and the cathode is grounded; the second end of the solenoid L1 is connected to the live wire L and is used for controlling the switch S to be turned on and off, and the rectifier bridge BD is used for rectifying the power grid voltage and generating a power supply voltage for supplying power to the leakage protection module; and a manual detection button BT and a resistor R which are connected in series are connected between the live wire L and the zero wire N. When the power grid has a leakage fault, for example, a factor affecting a main line current appears at a node Q, which causes that the sum of current vectors between the live line L and the zero line N is not zero, so that the magnetic flux in the induction coil N1 changes, an induction potential is induced and sent to the leakage protection module 10, the leakage protection module 10 sends a conduction signal to the control end of the thyristor SQ, the thyristor SQ and the solenoid L1 are conducted, the solenoid L1 opens the switch S, and a closed loop between the live line L and the zero line N is cut off, thereby playing a protection role. The manual detection switch BT can be used for manually detecting whether the circuit breaker can work normally. Therefore, the circuit breaker is often used for protecting the circuit, and when the circuit breaks down, the circuit circulation is cut off in time, and personal safety is guaranteed. But the circuit breaker does not have overvoltage and undervoltage detection and protection functions.

Fig. 2 shows a schematic block diagram of a leakage protection circuit according to an embodiment of the present invention. Fig. 3 shows a schematic block diagram of a leakage protection circuit connected to an ac main according to an embodiment of the present invention.

As shown in fig. 2, the leakage protection circuit 100 includes a rectifying module 110, a sensing module 120, a power supply module 130, a trip protection module 140, a voltage detection module 150, a self-test module 180, and a leakage protection chip IC 1. The voltage detection module 150 includes a voltage division module 101, a voltage division filtering module 105, an under-voltage sampling trigger module 102, an under-voltage sampling module 103, an over-voltage sampling module 104, and a sampling voltage filtering module 106.

As shown in fig. 3, the leakage protection circuit 100 of fig. 2 is connected to an ac main line. Referring to fig. 2, the live line L and the neutral line N are connected to a power supply terminal and a load 190, the switch S1 controls the on/off of the power supply circuit, and the power supply terminal receives an ac signal for supplying a grid voltage.

The rectifying module 110 includes a first diode D1 (not shown in the figure), connected to the live line L of the ac main line, for example, connected to the ac main line through the trip protection circuit 140, for rectifying an ac signal generated by the ac circuit, and transmitting the rectified signal to the power module 130 and the voltage detection module 150, respectively; the sensing module 120 is coupled to an ac main line (including a live line L and a neutral line N), and is configured to convert a magnetic flux variation at the coupling into a trigger signal and output the trigger signal to the earth leakage protection chip IC1, where when a sum of current vectors on the ac main line is not zero, a magnetic flux variation is caused, and the sensing module 120 generates the trigger signal according to the magnetic flux variation; the power supply module 130 is connected with the rectifying module 110 and the leakage protection chip IC1, and supplies rectified alternating current signals to the leakage protection chip IC1 to supply power to the leakage protection chip IC 1; the leakage protection chip IC1 is connected to the sensing module 120, and generates a conduction signal according to the received trigger signal; the voltage detection module 150 is connected with the rectification module 110 and the leakage protection chip IC1, detects the grid voltage on the ac main line and compares the grid voltage with a protection threshold, generates a voltage detection signal according to the comparison result, inputs the voltage detection signal to the leakage protection chip IC1 (compared with the threshold voltage at the corresponding pin inside the chip IC 1), and generates a conduction signal according to the voltage detection signal by the leakage protection chip IC 1; the trip protection module 140 is connected to the ac main line and the leakage protection chip IC1, respectively, and is configured to disconnect a power connection on the ac main line according to the conduction signal, thereby disconnecting the power supply loop.

Further, the voltage detection module 150 includes an overvoltage detection module 160 and an undervoltage detection module 170, a composition of the overvoltage detection module 160 is shown inside the voltage detection module 150 of fig. 2, a composition of the undervoltage detection module 170 is shown inside the voltage detection module 150 of fig. 3, and some modules inside the voltage detection module 150 are shared by the overvoltage detection module 160 and the undervoltage protection module 170. Specifically, the overvoltage detection module 160 and the undervoltage detection module 170 multiplex the voltage division module 101, the divided voltage filtering module 105 and the sampling voltage filtering module 106, wherein the divided voltage filtering module 105 filters the voltage divided by the voltage division module 101, the sampling voltage filtering module 106 filters the sampling voltage, and the voltage division module 101 is connected with the rectification module 110; the overvoltage detection module 160 further includes an overvoltage sampling module 104, the overvoltage sampling module 104 is connected to the leakage protection chip IC1, the overvoltage detection signal is input to the leakage protection chip IC1, and compared with a threshold voltage (saturation voltage drop of a diode) inside the chip IC1, the leakage protection chip IC1 generates a conduction signal according to a comparison result (the voltage of the overvoltage detection signal is higher than the saturation voltage drop of the diode); the undervoltage detection module 170 further includes an undervoltage sampling trigger module 102 and an undervoltage sampling module 103, the undervoltage sampling module 103 is connected to the leakage protection chip IC1, a voltage regulator diode in the undervoltage sampling trigger module 102 is not turned on under the condition that the power grid voltage is undervoltage (the power grid voltage is smaller than an undervoltage protection threshold), so that a control end of a transistor in the undervoltage sampling module 103 is triggered to be turned on, an undervoltage detection signal is input to the leakage protection chip IC1, and compared with a threshold voltage (diode saturation voltage drop) inside the chip IC1, the leakage protection chip IC1 generates a turn-on signal according to a comparison result.

The trip protection module 140 is connected to the trip unit S1 through a solenoid L1 (not shown in the figure), and can control the on/off of the trip unit S1, when the trip protection module 140 receives a conducting signal output by the leakage protection chip IC1, it indicates that a problem occurs somewhere in the circuit, for example, the power grid has a leakage, a grid voltage overvoltage or an undervoltage, and cannot supply power to the load any more, the conducting signal turns on the circuit inside the trip protection module 140, and controls the trip unit S1 to be off, and the power connection of the ac main line is disconnected, thereby protecting the circuit.

Further, the overvoltage detection module 160 and the undervoltage detection module 170 are configured to detect a voltage of the power grid, and when the voltage of the power grid is too large or too small, that is, the voltage of the power grid exceeds a set overvoltage protection threshold or is much smaller than the set undervoltage protection threshold, the power supply loop needs to be disconnected, and at this time, the overvoltage detection module 160 and the undervoltage detection module 170 send a voltage detection signal to the leakage protection chip IC1, where the voltage detection signal is used to indicate overvoltage or undervoltage of the power grid. Specifically, the voltage detection signal includes an overvoltage detection signal and an undervoltage detection signal, and when the grid voltage on the ac main line is greater than the overvoltage protection threshold, the overvoltage sampling module 104 in the overvoltage detection module 160 outputs the overvoltage detection signal; when the grid voltage on the ac main is smaller than the undervoltage protection threshold, the undervoltage sampling trigger module 102 in the undervoltage detection module 170 triggers the undervoltage sampling module 103 to output an undervoltage detection signal.

The leakage protection circuit 100 of this embodiment further includes a self-checking module 180, the self-checking module 180 is connected to the ac main line and connected between the live line L and the neutral line N, and the self-checking module 180 is coupled to the sensing module 120, and configured to change magnetic flux at a coupling position between the sensing module 120 and the ac main line according to external control, so as to control the sensing module 120 to generate a trigger signal. When the internal structure of the self-checking module 180 is controlled externally, the magnetic flux on the ac main line can be changed, and the sensing module 120 detects the change and generates a trigger signal, so as to perform self-checking on the leakage protection circuit, and detect whether the leakage protection chip IC1, the sensing module 120, and the trip protection module 140 can work normally, i.e., ensure the circuit breaker function of the leakage protection circuit.

According to the earth leakage protection circuit 100 of this embodiment, increased voltage detection module 150 on earth leakage protection's basis for detect grid voltage, and indicate when grid voltage is too high or low excessively, make earth leakage protection circuit 100 increase and cross undervoltage protection function, appear when grid voltage crosses undervoltage in the circuit, the circuit breaker can reliably break off, breaks off power supply circuit, therefore protection range is wider, more safe and reliable.

The leakage protection circuit 100 of the present embodiment has both the overvoltage protection function and the undervoltage protection function. The leakage protection circuit 100 comprises a rectification module 110, an induction module 120, a power module 130, a trip protection module 140, a voltage detection module 150, a self-checking module 180 and a leakage protection chip IC1, wherein the voltage detection module 150 comprises a voltage division module 101, a voltage division filtering module 105, a sampling voltage filtering module 106, an overvoltage sampling module 104, an undervoltage sampling trigger module 102 and an undervoltage sampling module 103. The functions of the modules are the same as those described in fig. 2 and 3, and the earth leakage protection chip IC1 includes first to eighth pins, which are connected to the modules respectively.

A live wire L and a zero line N in an alternating current main line are connected with a power supply end and a load end, the on-off of a power supply loop of the alternating current main line is controlled by a release S1, and the zero line N is grounded. The trip protection module 140 controls the opening and closing of the trip unit S1.

The leakage protection circuit 100 further comprises a piezoresistor, wherein the piezoresistor RV1 is connected between a zero line N and a live line L of an alternating current main line, overvoltage surge impact of power grid access is prevented, and lightning surge resistance is formed on the leakage protection circuit.

The rectifying module 110 includes a first diode D1, wherein the anode of the first diode D1 is connected to a solenoid L1 in the trip protection module 140, and is connected to the hot line of the main line through a solenoid L1, the solenoid L1 is also called a trip coil, and the cathode of the first diode D1 is connected to the power supply module 130 and the voltage dividing module 101.

The trip protection module 140 includes a solenoid L1, a rectifier diode D1 (a first diode D1) and a thyristor SCR, the solenoid L1, the rectifier diode D1 and the thyristor SCR are connected in series between the live line L and the ground, the rectifier diode D1 is mainly used for rectification, and due to the forward conduction characteristic of the diodes, the rectifier diode D1 rectifies the alternating current signal received by the power supply terminal to obtain a rectified signal, which is a sinusoidal half-wave signal and is valid only in the positive half-cycle. The cathode of the rectifier diode D1 is connected with the voltage dividing module 101 and the power module 130 respectively, the power module 130 generates a supply voltage for supplying power to the leakage protection chip IC1 according to the rectification signal, the voltage dividing module 101 is used for dividing the rectified voltage, and the overvoltage sampling module 104 and the undervoltage sampling module 103 triggered and conducted by the undervoltage sampling trigger module 102 generate an overvoltage detection signal and an undervoltage detection signal respectively. The rectification scheme adopted by the embodiment has strong anti-interference capability, easy popularization and strong practicability.

The power module 130 includes a thirteenth resistor R13 and a sixth capacitor C6, wherein one end of the thirteenth resistor R13 is connected to the cathode of the first diode D1, the other end of the thirteenth resistor R13 is connected to the eighth pin VDD of the leakage protection chip IC1, a first end of the sixth capacitor C6 is connected to the first end of the thirteenth resistor R13 and the eighth pin of the leakage protection chip IC1, and a second end of the sixth capacitor C6 is connected to ground. The intermediate node of the thirteenth resistor R13 and the sixth capacitor C6 provides a supply voltage for supplying power to the leakage protection chip IC 1.

The sensing module 120 is coupled to the ac main line and connected to the leakage protection IC1 for detecting the magnetic flux variation on the ac main line and generating the trigger signal Vtri according to the magnetic flux variation. The sensing module 120 includes a transformer SC1, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a tenth resistor R10, and an eleventh resistor R11. Two ends of the third capacitor C3, the fourth capacitor C4 and the tenth resistor R10 are connected in parallel to two output ends of the transformer SC 1. A common connection point of the third capacitor C3, the fourth capacitor C4 and the tenth resistor R10 is used as a first output end of the transformer SC1, one end of the eleventh resistor R11 is connected with a common end of the tenth resistor R10 and the third capacitor C3, the other end of the eleventh resistor R11 is connected with the fourth capacitor C4, a middle node of the eleventh resistor R11 and the fourth capacitor C4 is used as a second output end of the transformer SC1, the first output end and the second output end are respectively connected with the first pin InputA and the second pin InputB of the leakage protection chip IC1, and the trigger signal Vtri is provided to the leakage protection chip IC 1. A first end of the fifth capacitor C5 is connected to the first pin InputA of the leakage protection chip IC1, and the other end is grounded. The mutual inductor SC1 may induce a sum of current vectors on the ac main line, when a factor affecting current appears on the ac main line, such that the sum of current vectors between the live line L and the neutral line N is not zero, a change of magnetic flux may be generated in the coil, and the induction module 110 generates the trigger signal Vtri according to the change of magnetic flux, and outputs the trigger signal Vtri to the first pin InputA and the second pin InputB of the leakage protection chip IC1 through two output terminals.

The voltage detection module 150 has both functions of overvoltage detection and undervoltage detection, and when the grid voltage of the alternating current main line is greater than an overvoltage protection threshold, a voltage detection signal is an overvoltage detection signal and is transmitted to the leakage protection chip IC1 by the overvoltage sampling module 104; when the voltage of the power grid is smaller than the undervoltage protection threshold, the voltage detection signal is an undervoltage detection signal and is transmitted to the leakage protection chip IC1 by the undervoltage sampling module 103.

The leakage protection chip IC1 includes a plurality of pins, in this embodiment, 8 pins are taken as an example, and the first pin InputA and the second pin InputB are used for receiving the trigger signal Vtri; the third pin GND is grounded; the fourth pin NC is connected to the fifth pin Amout, and the fifth pin Amout is connected to the ground terminal through a seventh capacitor C7, that is, the seventh capacitor C7 is connected between the fifth pin Amout and the ground terminal as a filter capacitor; the sixth pin delay is connected to the voltage detection module 150, and is configured to receive the overvoltage detection signal Vover and the undervoltage detection signal Vunder; a seventh pin of the leakage protection chip IC1 is configured to generate a conducting signal Vcon according to the trigger signal Vtri and the voltage detection signal (Vover or Vunder), and a seventh pin SCR of the leakage protection chip IC1 is connected to the trip protection module 140 and provides the conducting signal Vcon to the trip protection module 140; the eighth pin VDD is connected to an intermediate node of the thirteenth resistor R13 and the sixth capacitor C6, and receives a supply voltage. Further, in the leakage protection chip IC1, a diode is connected between the sixth pin and the seventh pin, and when the voltage received by the sixth pin is higher than the saturation voltage drop of the diode, the voltage of the seventh pin is raised, and the voltage of the seventh pin is higher than 0.7V, which is enough to drive the SCR to turn on and pull the release S1 to trip. When the voltage detection module 150 transmits the voltage detection signal to the sixth pin of the leakage protection chip IC1, the leakage protection chip IC1 compares the voltage detection signal with the saturation voltage drop of the diode, so as to output the conduction signal Vcon at the seventh pin.

The voltage detection module 150 includes: the voltage stabilizing circuit comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a first capacitor C1, a second capacitor C2, a voltage stabilizing diode VD1, a second diode D2 and a transistor Q1. Specifically, the voltage dividing module 101 includes a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4, the voltage dividing and filtering module 105 includes a first capacitor C1, the sampling voltage filtering module 106 includes a second capacitor C2, the overvoltage sampling module includes a second diode D2 and a seventh resistor R7, the undervoltage sampling trigger module 102 includes a fifth resistor R5, a voltage stabilizing diode VD1, an eighth resistor R8 and a ninth resistor R9, and the undervoltage sampling module 103 includes a sixth resistor R6 and a transistor Q1. The divided voltage filtering module 105 filters the voltage divided by the divided voltage module 101, the sampling voltage filtering module 106 filters the voltage sampled by the overvoltage sampling module 104 or the undervoltage sampling module 103, the overvoltage sampling module 104 samples the voltage at the first end of the fourth resistor R4, and the cathode of the second diode D2 in the overvoltage sampling module 104 outputs an overvoltage detection signal to the leakage protection chip IC 1; the zener diode VD1 in the under-voltage sampling trigger module 102 is not turned on when the grid voltage is less than the under-voltage protection threshold, so that the control end of the transistor Q1 in the under-voltage sampling trigger module 103 is turned on, and the second end of the transistor Q1 outputs an under-voltage detection signal to the leakage protection chip IC 1. The sixth pin of the leakage protection chip IC1 receives the overvoltage detection signal and the undervoltage detection signal, compares the overvoltage detection signal with the threshold voltage (diode saturation drop) inside the leakage protection chip IC1, compares the undervoltage detection signal with the threshold voltage (diode saturation drop) inside the leakage protection chip IC1, and outputs the conduction signal Vcon through the seventh pin of the leakage protection chip IC1 to drive the trip protection module 140 to disconnect the power connection of the ac main line.

The first resistor R1 to the fourth resistor R4 are connected in series between the live line L of the ac main line and the ground in sequence, and serve as a plurality of voltage dividing resistors for dividing the rectified signal. The first end of the first resistor R1 is connected with the cathode of the first diode D1, the second end is connected with the first ends of the second resistor R2, the fifth resistor R5 and the first capacitor C1 respectively, the second end of the second resistor R2 is connected with the first ends of the third resistor R3 and the sixth resistor R6, the other end of the fifth resistor R5 is connected with the cathode of the zener diode VD1, and the other end of the first capacitor C1 is grounded. The first capacitor C1 is used for filtering, and the first capacitor C1 is, for example, a ceramic chip capacitor. The anode of the zener diode VD1 is connected to the first ends of the eighth resistor R8 and the ninth resistor R9, respectively, the second end of the eighth resistor R8 is grounded, the second end of the sixth resistor R6 is connected to the first end of the transistor Q1, the second end of the transistor Q1 outputs the voltage detection signal, the control end of the transistor Q1 is connected to the second end of the ninth resistor R9, and the transistor Q1 is, for example, a PNP-type triode. The seventh resistor R7 and the second diode D2 are connected in series between the second terminal of the third resistor R3 and the second terminal of the transistor Q2, and the second capacitor C2 is connected between the cathode of the second diode D2 and ground.

Further, the seventh resistor R7 is a current-limiting resistor, the second diode D2 is an inverting protection tube, the seventh resistor R7 and the second diode D2 are used for overvoltage detection, and when the grid voltage exceeds an overvoltage protection threshold, the overvoltage sampling module 104 outputs an overvoltage detection signal Vover to the leakage protection chip IC 1. The fifth resistor R5, the eighth resistor R8, the zener diode VD1, the sixth resistor R6, the ninth resistor R9, and the transistor Q1 are used for undervoltage detection in cooperation with the sixth pin delay of the leakage protection chip, when the voltage of the power grid is lower than an undervoltage protection threshold, the zener diode VD1 in the undervoltage sampling trigger module 102 is not turned on, the control end of the transistor Q1 in the undervoltage sampling module 103 is triggered to be turned on by grounding, and the undervoltage sampling module 103 outputs an undervoltage detection signal Vunder to the leakage protection chip IC 1. The over-voltage protection threshold is greater than the under-voltage protection threshold. The embodiment can realize the functions of overvoltage detection and undervoltage detection at the same time by arranging the voltage detection module 150, and has the advantages of simple circuit structure and lower cost.

The trip protection module further includes a third diode D3, an eighth capacitor C8, and a twelfth resistor R12. The first diode D1 is used to block the current path between the thyristor SCR and the solenoid L1 during the negative half cycle of the ac signal as a reverse protection tube. A control electrode (or called as a trigger pin) of the SCR is connected to the first ends of the third diode D3, the eighth capacitor C8, and the twelfth resistor R12, and is configured to receive the conduction signal Vcon, which controls the conduction of the SCR. The second ends of the eighth capacitor C8 and the twelfth resistor R12 are grounded, the anode of the third diode D3 is connected to the seventh pin SCR of the earth leakage protection chip IC1, the cathode of the thyristor SCR is grounded, that is, the eighth capacitor C2 and the twelfth resistor R12 are connected in parallel between the cathode of the third diode D3 and the ground, and the third diode D3 is a reverse protection tube. When the leakage protection chip IC1 receives the trigger signal Vtri or the voltage detection signal (the overvoltage detection signal Vover or the undervoltage detection signal Vunder), the conduction signal Vcon is output from the seventh pin SCR, so as to control the conduction of the silicon controlled rectifier SCR, so that the solenoid L1 operates, and the switch S1 is turned off, thereby disconnecting the power supply circuit and playing a role in protection. Therefore, in the positive half period of the alternating current signal, the overvoltage sampling module 104, the undervoltage sampling trigger module 102, the undervoltage sampling module 103 and the induction module 120 work simultaneously, the overvoltage sampling module 104 is used for overvoltage detection of the grid voltage, the undervoltage sampling trigger module 102 and the undervoltage sampling module 103 are used for undervoltage detection of the grid voltage, and the induction module 120 is used for leakage detection.

The self-checking module 180 includes a touch switch B1 and a fourteenth resistor R14, and the self-checking module 180 is a testing module of the whole leakage protection circuit, and is also a control module for artificially performing leakage detection, and is used for testing whether the leakage protection function is intact. When the touch switch B1 is pressed, the "live line L-fourteenth resistor R14-zero line N" forms a loop, the loop passes through the transformer SC1, the fourteenth resistor R14 determines the magnitude of the loop current, and the loop current passes through the transformer SC1 as an analog leakage current, and then is converted into the trigger signal Vtri by the transformer SC1 and is provided to the leakage protection chip IC 1. The leakage protection chip IC1 receives the trigger signal Vtri, and generates a turn-on signal Vcon according to the trigger signal Vtri to control the turn-on of the SCR. After the silicon controlled rectifier SCR is conducted, a loop formed by a live wire L-solenoid L1, a first diode D1, the silicon controlled rectifier SCR and a zero line N passes through a large current, and the solenoid L1 pulls a switch S1 to trip after the large current, so that the leakage protection function is realized.

The embodiment of the utility model provides an utilize earth leakage protection chip IC 1's sixth pin delay to carry out undervoltage detection, from circuit structure and with the cost, the circuit structure of this embodiment is simple, low cost, and the stable performance has more advantages from price and performance. An alarm module can be further arranged, when the circuit is under-voltage, the alarm is carried out, and the alarm can be realized in an LED flashing mode or a buzzer buzzing mode.

In this embodiment, the voltage detection signal is received mainly through the sixth pin delay of the leakage protection chip IC1, and the overvoltage/undervoltage detection determination is performed. The specific working principle is as follows: in the internal of the leakage protection chip IC1, the sixth pin delay and the seventh pin SCR are connected through a diode, and when the voltage of the sixth pin delay is higher than the saturation voltage drop of the diode, the voltage of the seventh pin SCR is raised, and the voltage of the seventh pin SCR is higher than 0.7V, which is enough to drive the SCR to turn on, so that the switch S1 is turned off.

The principle of the leakage protection chip IC1 for realizing overvoltage detection is as follows: the voltage pulled down by the fourth resistor R4 in the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 is provided to the sixth pin delay of the leakage protection chip IC1 through the seventh resistor R7 and the second diode D2, that is, a voltage detection signal is output to the leakage protection chip IC1, when the grid voltage exceeds the overvoltage protection threshold, the voltage pulled down by the fourth resistor R4 rises to exceed the threshold voltage of the sixth pin delay, the turn-on signal Vcon generated by the seventh pin is driven to control the turn-on of the thyristor SCR, and the switch S1 is driven to turn off.

The principle of the leakage protection chip IC1 for realizing undervoltage detection is as follows: the voltage pulled down by the third resistor R3 and the fourth resistor R4 in the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 is provided to the sixth pin delay of the leakage protection chip IC1 by the sixth resistor R6 and the transistor Q1, that is, the voltage detection signal is output to the leakage protection chip IC 1. When the grid voltage is less than the undervoltage protection threshold, the voltage obtained by pulling down the second resistor R2, the third resistor R3 and the fourth resistor R4 in the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 is lower than the voltage stabilizing value of the zener diode VD1, the transistor Q1 is turned on, the voltage (>3.5V) obtained by pulling down the third resistor R3 and the fourth resistor R4 is provided to the sixth pin delay of the leakage protection chip IC1, the turn-on signal Vcon generated by the seventh pin is driven to control the turn-on of the SCR, and the switch S1 is driven. The overvoltage protection threshold and the undervoltage protection threshold are determined by the resistance values of the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4.

In practical application, the working principle of the leakage protection circuit is as follows: the 230V ac signal is rectified by the first diode D1 to obtain a rectified signal, the rectified signal generates a supply voltage through the thirteenth resistor R13 and the sixth capacitor C6, and is provided to the power supply terminal of the leakage protection chip IC1, i.e., the eighth pin VDD, and the rectified signal is provided to the overvoltage detection module 160 and the undervoltage detection module 170, when the grid voltage is overvoltage, the voltage value of the common terminal of the third resistor R3 and the fourth resistor R4 exceeds 3.5V, the seventh pin SCR of the leakage protection chip IC1 outputs a high-level conduction signal Vcon to control the conduction of the silicon controlled SCR, and the solenoid L1 drives the switch S1 to turn off, and turns off the power supply to perform overvoltage protection.

When the voltage of the power grid is under-voltage, the current flowing through the voltage-stabilizing diode VD1 is sharply reduced, the voltage at the control end of the transistor Q1 becomes a low level, the transistor Q1 is turned on, the voltage at the common end of the second resistor R2 and the third resistor R3 is provided to the sixth pin delay of the leakage protection chip IC1 through the transistor Q1, the seventh pin SCR of the leakage protection chip IC1 outputs a high-level conduction signal Vcon to control the conduction of the silicon controlled rectifier SCR, and the solenoid L1 drives the switch S1 to be turned off to disconnect the power supply to perform under-voltage protection.

The leakage protection circuit of the present embodiment is basically the same as the first embodiment, except that the voltage detection module of the present embodiment only includes the overvoltage detection module 260, and thus, only has an overvoltage detection function.

The leakage protection circuit 200 includes a rectifying module 210, an induction module 220, a power module 230, a trip protection module 240, an overvoltage detection module 260, a self-detection module 280, and a leakage protection chip IC1, and except for the overvoltage detection module 260, circuit connections, functions, and the like of other modules are the same as those in the first embodiment, and are not described herein again.

The overvoltage detection module 260 includes a voltage dividing module 201, a voltage dividing and filtering module 205, an overvoltage sampling module 204 and a sampling voltage filtering module 206, wherein the voltage dividing module 201 includes a first resistor R1 to a fourth resistor R4, the voltage dividing and filtering module 205 includes a first capacitor C1, the sampling voltage filtering module 206 includes a second capacitor C2, the overvoltage sampling module 204 includes a second diode D2 and a seventh resistor R7, the voltage dividing and filtering module 205 filters the voltage divided by the voltage dividing and filtering module 201, the sampling voltage filtering module 206 filters the voltage sampled by the overvoltage sampling module 204, the overvoltage sampling module 204 samples the voltage at the first end of the fourth resistor R4, and the cathode of the second diode D2 in the overvoltage sampling module 204 outputs an overvoltage detection signal Vover to the leakage protection chip 1.

The overvoltage detection module 250 of the present embodiment removes the fifth resistor R5, the zener diode VD1, the eighth resistor R8, the ninth resistor R9, the sixth resistor R6, and the transistor Q1 from the first embodiment, so that only the overvoltage protection function can be implemented. At this time, when the grid voltage is overvoltage, the voltage pulled down by the fourth resistor R4 in the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 is provided to the sixth pin delay of the leakage protection chip IC1 through the seventh resistor R7 and the second diode D2, that is, the overvoltage detection signal Vover, so as to implement overvoltage protection. And in this embodiment the leakage protection function is not affected.

The leakage protection circuit of this embodiment is basically the same as the first embodiment, except that the voltage detection module of this embodiment only includes the under-voltage detection module 360, and thus only has an under-voltage detection function.

The leakage protection circuit 300 includes a rectifying module 310, an induction module 320, a power module 330, a trip protection module 340, an undervoltage detection module 370, a self-checking module 380, and a leakage protection chip IC1, and except for the undervoltage detection module 370, the circuit connections and functions of other modules are the same as those in the first embodiment, and are not described herein again.

The undervoltage detection module 370 includes a voltage dividing module 301, a voltage dividing and filtering module 305, an undervoltage sampling trigger module 302, an undervoltage sampling module 303 and a sampling voltage filtering module 306, wherein the voltage dividing module 301 includes a first resistor R1 to a fourth resistor R4, the voltage dividing and filtering module 305 includes a first capacitor C1, the undervoltage sampling trigger module 302 includes a fifth resistor R5, a voltage regulator diode VD1, an eighth resistor R8 and a ninth resistor R9, the undervoltage sampling module 303 includes a sixth resistor R6 and a transistor Q1, the voltage dividing and filtering module 305 filters the voltage divided by the voltage dividing and sampling module 301, the sampling voltage filtering module 306 filters the voltage sampled by the undervoltage sampling module 303, the voltage regulator diode VD1 in the undervoltage sampling trigger module 302 is not turned on when the grid voltage is less than the undervoltage protection threshold, the control terminal of the transistor Q1 in the trigger sampling module 303 is turned on to ground, the second terminal of the transistor Q1 outputs an under-voltage detection signal to the leakage protection chip IC 1.

The undervoltage detection module 370 of this embodiment is formed by removing the seventh resistor R7 and the second diode D2 from the first embodiment, and has only an undervoltage protection function. When the grid voltage is undervoltage, the transistor Q1 is turned on, and the voltage obtained by pulling down the third resistor R3 and the fourth resistor R4 in the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 is provided to the sixth pin delay of the leakage protection chip by the sixth resistor R6 and the transistor Q1, that is, the undervoltage signal Vunder. And in this embodiment, the leakage protection function is not affected.

The utility model discloses set up voltage detection module among the earth leakage protection circuit, can detect grid voltage, when grid voltage surpassed the overvoltage protection threshold value or was less than the undervoltage protection threshold value, send the voltage detection signal to the detection pin of earth leakage protection chip, the earth leakage protection chip produces turn-on signal according to this received voltage detection signal, and by another pin output turn-on signal, the control silicon controlled rectifier switches on, thereby connect through dropout protection module disconnection source, play the guard action to circuit and follow-up load. The leakage protection circuit adopts simple elements to realize the over-voltage and under-voltage protection function, can quickly realize the over-voltage and under-voltage protection of the chip and protect the personal safety of a user, has simple circuit structure and stable performance, improves the working efficiency, also reduces the manufacturing cost and has high circuit reliability.

The embodiments of the invention are described above, and these embodiments do not set forth any exhaustive details, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and its various embodiments with various modifications as are suited to the particular use contemplated. The protection scope of the present invention should be subject to the scope defined by the claims of the present invention.

Claims

1. An earth leakage protection circuit, comprising:

the induction module is coupled with an alternating current main line and generates a trigger signal according to the change of the magnetic flux at the coupling part;

2. The earth leakage protection circuit of claim 1, further comprising:

3. The earth leakage protection circuit of claim 2, further comprising:

4. The earth leakage protection circuit of claim 2, wherein the voltage detection module comprises an overvoltage detection module, the voltage detection signal is an overvoltage detection signal when the grid voltage on the ac main line is greater than an overvoltage protection threshold, and the earth leakage protection chip controls the trip protection module to disconnect the power supply connection of the ac main line according to the overvoltage detection signal.

5. The leakage protection circuit of claim 2, wherein the voltage detection module comprises an under-voltage detection module, the voltage detection signal is an under-voltage detection signal when the grid voltage on the ac main line is smaller than an under-voltage protection threshold, and the leakage protection chip controls the trip protection module to disconnect the power connection of the ac main line according to the under-voltage detection signal.

6. The earth leakage protection circuit of claim 2, wherein the voltage detection module comprises an overvoltage detection module and an undervoltage detection module, and when the grid voltage on the ac main line is greater than an overvoltage protection threshold and the grid voltage on the ac main line is less than an undervoltage protection threshold, the earth leakage protection chip controls the trip protection module to disconnect the power connection of the ac main line according to the voltage detection signal.

7. The earth leakage protection circuit of claim 4, wherein the overvoltage detection module comprises: the overvoltage protection device comprises a voltage dividing module, a voltage dividing voltage filtering module, an overvoltage sampling module and a sampling voltage filtering module, wherein the voltage dividing voltage filtering module is right for filtering the divided voltage of the voltage dividing module, the sampling voltage filtering module is right for filtering the voltage sampled by the overvoltage sampling module, and the overvoltage sampling module is right for sampling the voltage of the voltage dividing module and outputting an overvoltage detection signal to the leakage protection chip.

8. The leakage protection circuit of claim 5, wherein the under-voltage detection module comprises: partial pressure module, partial pressure voltage filter module, undervoltage sampling trigger module, undervoltage sampling module and sampling voltage filter module, partial pressure voltage filter module is right the voltage that partial pressure module divides is filtered, sampling voltage filter module is right the voltage of undervoltage sampling module sampling filters, zener diode in the undervoltage sampling trigger module is in grid voltage is less than do not switch on when the undervoltage protection threshold value, triggers the control termination ground of the transistor in the undervoltage sampling module switches on, the second end of transistor to the undervoltage detection signal of earth leakage protection chip output.

9. The leakage protection circuit of claim 6, wherein the voltage detection module comprises a voltage division module, a voltage division voltage filtering module, an overvoltage sampling module, a sampling voltage filtering module, an undervoltage sampling trigger module and an undervoltage sampling module, the voltage division voltage filtering module filters the voltage divided by the voltage division module, the sampling voltage filtering module filters the voltage sampled by the overvoltage sampling module or the undervoltage sampling module, the overvoltage sampling module samples the voltage of the voltage division module, and a cathode of a second diode in the overvoltage sampling module outputs an overvoltage detection signal to the leakage protection chip; and when the voltage of the power grid is smaller than the undervoltage protection threshold value, a voltage stabilizing diode in the undervoltage sampling trigger module is not conducted, so that the control end of a transistor in the undervoltage sampling module is triggered to be conducted in a grounded mode, and the second end of the transistor outputs an undervoltage detection signal to the leakage protection chip.

10. The leakage protection circuit of claim 7, wherein the over-voltage detection module comprises a first resistor, a second resistor, a third resistor, and a fourth resistor, wherein the divided-voltage filtering module comprises a first capacitor, wherein the sampled-voltage filtering module comprises a second capacitor, and wherein the over-voltage sampling module comprises a second diode and a seventh resistor, wherein,

11. The leakage protection circuit of claim 8, wherein the under-voltage detection module comprises a first resistor, a second resistor, a third resistor, and a fourth resistor, wherein the voltage-dividing module comprises a first capacitor, wherein the under-voltage sampling trigger module comprises a fifth resistor, a zener diode, an eighth resistor, and a ninth resistor, wherein the under-voltage sampling module comprises a sixth resistor and a transistor, wherein the sampling voltage filtering module comprises a second capacitor, and wherein,

12. The leakage protection circuit of claim 9, wherein the voltage detection module, the voltage division module, the sampling voltage filtering module, the overvoltage sampling module, the undervoltage sampling triggering module, the undervoltage sampling module, the transistor and the voltage regulation module are arranged in parallel, wherein the voltage division module comprises a first resistor, a second resistor, a third resistor and a fourth resistor, the voltage division module comprises a first capacitor, the sampling voltage filtering module comprises a second capacitor, the overvoltage sampling module comprises a second diode and a seventh resistor, the undervoltage sampling triggering module comprises a fifth resistor, a voltage regulation diode, an eighth resistor and a ninth resistor, the undervoltage sampling module comprises a sixth resistor and a transistor, and wherein,

13. The leakage protection circuit of any of claims 2-12, wherein the rectifying module comprises:

14. The earth leakage protection circuit of claim 2, wherein the sensing module comprises:

15. The earth leakage protection circuit of claim 14, wherein the trip protection module comprises:

and the twelfth resistor is connected with the eighth capacitor in parallel.

16. The earth leakage protection circuit of claim 15, wherein the earth leakage protection chip comprises a first pin through an eighth pin, wherein,

a first pin is connected to a first end of the fourth capacitor,

the third pin is grounded;

the fourth pin is connected to the fifth pin,

the fifth pin is connected to the ground terminal through a seventh capacitor;

the eighth pin is connected to the power module and receives a supply voltage.

17. The leakage protection circuit of claim 16, wherein the voltage detection module comprises an over-voltage detection module and an under-voltage detection module, when the grid voltage on the alternating current main line is larger than the overvoltage protection threshold value, the voltage detection signal is an overvoltage detection signal, when the voltage of the power grid on the alternating current main line is smaller than the undervoltage protection threshold value, the voltage detection signal is an undervoltage detection signal, the sixth pin of the leakage protection chip receives an overvoltage detection signal output by the overvoltage detection module and an undervoltage detection signal output by the undervoltage detection module, compares the overvoltage detection signal and the undervoltage detection signal with a saturation voltage drop of the sixth pin of the leakage protection chip, and outputting a conducting signal through the seventh pin of the leakage protection chip to drive the tripping protection module to disconnect the power supply connection of the alternating current trunk line.

18. The leakage protection circuit of claim 16, wherein the power module comprises:

19. The leakage protection circuit of claim 18, wherein the voltage detection module and the sensing module operate simultaneously during a positive half-cycle of the ac signal.

20. The earth leakage protection circuit of any one of claims 1-12, further comprising a varistor connected between the neutral line and the live line of the ac mains to provide lightning surge protection to the earth leakage protection circuit.