A control circuit of a leakage protection switch device

Abstract

The invention discloses a control circuit of a leakage protection switch device, which includes a power supply terminal connected to an input power supply, an output terminal connected to a load, and an MCU control circuit. A switch controlled by a coil is connected to the live wire, neutral wire, and ground wire between the power supply terminal and the output terminal. The MCU control circuit is connected with a power supply anti-shake detection circuit for detecting the positive and negative cycle voltage waveforms of the input power supply, and a coil large current suction circuit for outputting a large current to make the coil energized and suck the switch when the power supply anti-shake detection circuit detects that the input power supply voltage waveform is a sine wave within a preset time. The power supply terminal is connected with a coil small current suction circuit for maintaining the coil energized and sucked after the coil sucks the switch. The invention realizes automatic reset after power failure and re-power on, and must be manually reset to be powered on after pressing the test switch or leakage. The standby power consumption is low, and accidental accidents are avoided.

Description

Technical Field

[0001] The present invention relates to a control circuit for a leakage protection switch device. Background Art

[0002] At present, leakage protection switch devices on the domestic market, such as leakage protection plugs, generally have the following defects:

[0003] 1. After the input power supply is disconnected, the switch of the control circuit cannot be automatically disconnected and remains in the connected state.

[0004] 2. When the user presses the test switch or reconnects the input power supply after a leakage accident, since the switch has been in the connected state, the switch is turned on to connect the power supply, which may damage the load electrical appliance and cause a safety accident.

[0005] 3. When the leakage protection plug is in poor contact with the socket, the voltage waveform of the input power supply is not a sine wave, which may also damage the load electrical appliance and shorten the service life of the load electrical appliance.

[0006] 4. The standby power of the leakage protection plug is high, consuming too much electricity, which does not conform to the concept of green and environment-friendly electricity use.

[0007] 5. The control circuit and structure of the leakage protection plug are complex, with low production efficiency and high product cost, which is not conducive to market promotion. Summary of the Invention

[0008] The present invention overcomes the above-mentioned deficiencies in the art and provides a control circuit for a leakage protection switch device.

[0009] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0010] A control circuit for a leakage protection switch device of the present invention includes a power supply terminal 1 connected to an input power supply, an output terminal 4 connected to a load, and an MCU control circuit 6. A switch 2 controlled by a coil 3 is connected to the live wire, neutral wire, and ground wire between the power supply terminal 1 and the output terminal 4. The MCU control circuit 6 is connected to a power supply anti-shake detection circuit 5 for detecting the positive and negative cycle voltage waveforms of the input power supply, and a coil large current suction circuit 7 for outputting a large current to energize the coil 3 to attract the switch 2 when the power supply anti-shake detection circuit 5 detects that the input power supply voltage waveform is a sine wave within a preset time. The power supply terminal 1 is connected to a coil small current suction circuit 8 for maintaining the coil 3 energized and attracted after the coil 3 attracts the switch 2.

[0011] A control circuit of a leakage protection switch device as described above, characterized in that the MCU control circuit 6 is further connected to an MCU leakage signal detection circuit 10, the MCU leakage signal detection circuit 10 is connected to a thyristor SCR1, an LN line leakage detection and control circuit 11 for detecting a leakage signal of the live wire or neutral wire at the output terminal 4, and a PE line fault current detection and control circuit 12 for detecting a leakage signal of the ground wire at the output terminal 4. When the LN line leakage detection and control circuit 11 or the PE line fault current detection and control circuit 12 detects a leakage signal, the MCU leakage signal detection circuit 10 outputs the leakage signal to the MCU control circuit 6 and controls the thyristor SCR1 to conduct, so that the coil 3 is powered off and does not attract the switch 2.

[0012] A control circuit of a leakage protection switch device as described above, characterized in that the MCU control circuit 6 is connected to an over-temperature detection circuit 17 for detecting the temperature of the live wire or neutral wire pin, an over-temperature protection control circuit 9 for outputting an analog leakage signal when the pin temperature exceeds the set temperature. The live wire at the output terminal 4 is connected to a TEST analog leakage circuit 15 for manually testing and outputting an analog leakage signal. When the LN line leakage detection and control circuit 11 detects the analog leakage signal of the over-temperature protection control circuit 9 or the TEST analog leakage circuit 15, the MCU leakage signal detection circuit 10 outputs the analog leakage signal to the MCU control circuit 6 and controls the thyristor SCR1 to conduct, so that the coil 3 is powered off and does not attract the switch 2.

[0013] A control circuit of a leakage protection switch device as described above, characterized in that a ground fault indication circuit 13 that emits light when the ground wire is energized is connected between the neutral wire and the ground wire of the power supply terminal 1, a power indication circuit 14 that emits light when the live wire at the output terminal 4 is energized is connected between the live wire at the output terminal 4 and the neutral wire of the power supply terminal 1. The MCU control circuit 6 is powered by an MCU control power supply resistor-capacitor step-down circuit 16. The MCU control circuit 6 is connected to a power-on reset circuit 18 for manual reset, a TEST and leakage alarm indication circuit 19 that emits light during leakage. The LN line leakage detection and control circuit 11 and the PE line fault current detection and control circuit 12 are powered by a leakage control power supply resistor-capacitor step-down circuit 20.

[0014] A control circuit of a leakage protection switch device as described above, characterized in that the power supply anti-shake detection circuit 5 includes a triode Q2. The emitter of the triode Q2 is electrically connected to the neutral line of the power supply terminal 1. The base of the triode Q2 is electrically connected to one end of a resistor 26 and one end of a resistor 27. The other end of the resistor 26 is electrically connected to one end of a resistor R14. The other end of the resistor R14 is electrically connected to the live wire of the power supply terminal 1. The other end of the resistor R27 is electrically connected to the neutral line of the power supply terminal 1. The collector of the triode Q2 is electrically connected to the pin P00 of the MCU control circuit 6.

[0015] A control circuit of a leakage protection switch device as described above, characterized in that the coil large current suction circuit 7 includes a micro control unit U2. The pin LED+ of the micro control unit U2 is electrically connected to one end of a resistor R11. The other end of the resistor R11 is electrically connected to the pin P01 of the MCU control circuit 6. The pin LED- of the micro control unit U2 is electrically connected to the neutral line of the power supply terminal 1. The pin Terminal1 of the micro control unit U2 is electrically connected to one end of the coil 3. The pin Terminal2 of the micro control unit U2 is electrically connected to the negative electrode of a diode D9. The positive electrode of the diode D9 is electrically connected to one end of a resistor R15. The other end of the resistor R15 is electrically connected to the live wire of the power supply terminal 1. The other end of the coil 3 is electrically connected to the neutral line of the power supply terminal 1.

[0016] A control circuit of a leakage protection switch device as described above, characterized in that the small current suction circuit 8 includes a resistor R1A. One end of the resistor R1A is electrically connected to one end of a resistor R1B. The other end of the resistor R1B is electrically connected to one end of a capacitor C1 and the live wire of the power supply terminal 1. The other end of the resistor R1A is electrically connected to the other end of the capacitor C1, the negative electrode of a diode D5 and the positive electrode of a diode D7. The positive electrode of the diode D5 is electrically connected to the neutral line of the power supply terminal 1, the negative electrode of a polar capacitor C6 and one end of the coil 3. The negative electrode of the diode D7 is electrically connected to the positive electrode of the polar capacitor C6 and the other end of the coil 3.

[0017] A control circuit of a leakage protection switch device as described above, characterized in that the MCU leakage signal detection circuit 10 includes a triode Q5. The collector of the triode Q5 is electrically connected to one end of a resistor R6 and the pin P02 of the MCU control circuit 6. The other end of the resistor R6 is electrically connected to the pin VDD of the MCU control circuit 6. The emitter of the triode Q5 is electrically connected to one end of a capacitor C19 and the neutral wire of the power supply terminal 1. The base of the triode Q5 is electrically connected to the other end of the capacitor C19 and one end of a resistor R9. The other end of the resistor R9 is electrically connected to one end of a resistor R12 and the output terminal of a dual-path switching diode Q3. One input terminal of the dual-path switching diode Q3 is electrically connected to the pin SCR of the micro control unit U1 of the LN line leakage detection control circuit 11. The other input terminal of the dual-path switching diode Q3 is electrically connected to the pin SCR of the micro control unit U1E of the PE line fault current detection control circuit 12. The other end of the resistor R12 is electrically connected to one end of a capacitor C7 and the control electrode of the thyristor SCR1. The other end of the capacitor C7 is electrically connected to the neutral wire of the power supply terminal 1 and the negative electrode of the thyristor SCR1. The positive electrode of the thyristor SCR1 is electrically connected to one end of the coil 3.

[0018] A control circuit of a leakage protection switch device as described above, characterized in that the LN line leakage detection control circuit 11 includes a micro control unit U1. One end of the pin Neutral of the micro control unit U1 is electrically connected to one end of the capacitor C11 and the neutral line of the power supply terminal 1. One end of the pin Line of the micro control unit U1 is electrically connected to one end of the resistor R2 of the leakage control power supply capacitive voltage reduction circuit 20 and one end of the capacitor C8. The other end of the capacitor C8 is electrically connected to the neutral line of the power supply terminal 1. One end of the pin VREF of the micro control unit U1 is electrically connected to the other end of the capacitor C11, one end of the capacitor C9, one end of the resistor R16 and one end of the zero-sequence current transformer ZCT1. The other end of the zero-sequence current transformer ZCT1 is electrically connected to the other end of the resistor R16, the other end of the capacitor C9 and one end of the resistor R17. The other end of the resistor R17 is electrically connected to one end of the capacitor C10, one end of the resistor R18 and the pin VFB of the micro control unit U1. The pin AmpOUT of the micro control unit U1 is electrically connected to the other end of the capacitor C10 and the other end of the resistor R18. The live wire and neutral line of the output terminal 4, the connection line between the emitter of the triode Q1 of the over-temperature protection control circuit 9 and the neutral line of the power supply terminal 1, and the connection line between the test switch TEST of the TEST analog leakage circuit 15 and the live wire of the output terminal 4 all pass through the center of the zero-sequence current transformer ZCT1. The PE line fault current detection control circuit 12 includes a micro control unit U1E. One end of the pin Neutral of the micro control unit U1E is electrically connected to one end of the capacitor C14 and the neutral line of the power supply terminal 1. One end of the pin Line of the micro control unit U1E is electrically connected to one end of the resistor R2 of the leakage control power supply capacitive voltage reduction circuit 20 and one end of the capacitor C8. One end of the pin VREF of the micro control unit U1E is electrically connected to the other end of the capacitor C14, one end of the capacitor C13, one end of the resistor R20 and one end of the zero-sequence current transformer ZCT2. The other end of the zero-sequence current transformer ZCT2 is electrically connected to the other end of the resistor R20, the other end of the capacitor C13 and one end of the resistor R21. The other end of the resistor R21 is electrically connected to one end of the capacitor C12, one end of the resistor R19 and the pin VFB of the micro control unit U1E. The pin AmpOUT of the micro control unit U1E is electrically connected to the other end of the capacitor C12 and the other end of the resistor R19. The ground wire of the output terminal 4 passes through the center of the zero-sequence current transformer ZCT2.

[0019] A control circuit of a leakage protection switch device as described above, characterized in that the over-temperature detection circuit 17 includes a thermistor R3. One end of the thermistor R3 is electrically connected to the neutral line of the power supply terminal 1 and one end of a capacitor C5. The other end of the thermistor R3 is electrically connected to one end of a resistor R4 and one end of a resistor R5. The other end of the resistor R4 is electrically connected to the pin VDD of the MCU control circuit 6. The other end of the resistor R5 is electrically connected to the pin P03 of the MCU control circuit 6 and the other end of the capacitor C5. The over-temperature protection control circuit 9 includes a triode Q1. The collector of the triode Q1 is electrically connected to one end of a resistor R15B. The other end of the resistor R15B is electrically connected to one end of a resistor R15A. The other end of the resistor R15A is electrically connected to the negative electrode of a diode D8. The positive electrode of the diode D8 is electrically connected to the live wire of the power supply terminal 1. The emitter of the triode Q1 is electrically connected to the neutral line of the power supply terminal 1. The base of the triode Q1 is electrically connected to one end of a resistor R28 and one end of a resistor R7. The other end of the resistor R28 is electrically connected to the neutral line of the power supply terminal 1. The other end of the resistor R7 is electrically connected to the pin P05 of the MCU control circuit 6. The TEST analog leakage circuit 15 includes a test switch TEST. One end of the test switch TEST is electrically connected to the live wire of the output terminal 4. The other end of the test switch TEST is electrically connected to one end of a resistor R9B. The other end of the resistor R9B is electrically connected to one end of a resistor R9A. The other end of the resistor R9A is electrically connected to the neutral line of the power supply terminal 1.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. After the present invention is powered on, it first detects the positive and negative cycle voltage waveforms of the input power supply. When the input power supply voltage waveform is a sine wave within a preset time, the control circuit closes the switch to connect the power supply, and the load electrical appliance connected to the output terminal is powered on and works; when the input power supply is disconnected, the switch of the control circuit can automatically disconnect.

[0022] 2. When the input power supply is disconnected and then powered on again, the control circuit can automatically reset without manual operation.

[0023] 3. When the user actively presses the test switch or a leakage accident occurs, the input power supply can be immediately disconnected and an alarm prompt is issued. It is necessary to manually press the reset switch to reset and power on.

[0024] 4. When the voltage waveform of the input power supply is not a sine wave, such as when the leakage protection plug is in poor contact with the socket, the control circuit can actively disconnect the power supply to avoid damaging the load electrical appliance and extend the service life of the load electrical appliance.

[0025] 5. When the pin temperature of the live wire or the neutral wire exceeds the set temperature, the control circuit can actively disconnect the input power supply. When the pin temperature drops below the set temperature, the control circuit can automatically connect the power supply.

[0026] 6. The power supply of the control circuit adopts a resistor-capacitor step-down circuit, which can reduce the heat generated during operation, reduce the power consumption during standby, and is green and environmentally friendly.

[0027] 7. The structure of the present invention is simple and easy to implement, has good practicability, and can greatly improve the use safety. [Description of the Drawings]

[0028] Figure 1 is the logic diagram of the control circuit of the present invention;

[0029] Figure 2 is the schematic diagram of the control circuit of the present invention. [Detailed Embodiments]

[0030] The following is a more detailed description in conjunction with the drawings and the embodiments of the present invention:

[0031] As Figure 1-2 shown, a control circuit of a leakage protection switch device includes a power supply terminal 1 connected to the input power supply, an output terminal 4 connected to the load, and an MCU control circuit 6. A switch 2 controlled by a coil 3 is connected to the live wire, neutral wire, and ground wire between the power supply terminal 1 and the output terminal 4. The MCU control circuit 6 is connected to a power supply anti-shake detection circuit 5 for detecting the positive and negative cycle voltage waveforms of the input power supply, and a coil large current suction circuit 7 for outputting a large current to make the coil 3 energized and attract the switch 2 when the power supply anti-shake detection circuit 5 detects that the input power supply voltage waveform is a sine wave within a preset time. The power supply terminal 1 is connected to a coil small current suction circuit 8 for maintaining the coil 3 energized and attracted after the coil 3 attracts the switch 2.

[0032] When the power is just turned on, the power supply anti-shake detection circuit 5 processes the voltage waveform of the input power supply and outputs the processed input power supply voltage waveform to the MCU control circuit 6. When the voltage waveform is a sine wave within the preset time of 2 seconds, the MCU control circuit 6 outputs a high level to the coil large current suction circuit 7, and the high level lasts for within 50 milliseconds, driving the coil large current suction circuit 7 to output a large current to make the coil 3 energized to suck the switch 2. The coil small current suction circuit 8 can output a small current to the coil 3 to maintain the coil 3 energized to suck the switch 2. When the input power supply is disconnected, the entire control circuit is powered off and stops working, the coil 3 loses current, stops sucking the switch 2, and the switch 2 is disconnected. When the power is turned on again, the control circuit repeats the above process, thus realizing the function that the switch automatically disconnects after the input power supply is disconnected and automatically resets and powers on again when the input power supply is connected again, without manual operation. When the voltage waveform of the input power supply is not a sine wave, such as when the leakage protection plug is in poor contact with the socket, the control circuit actively disconnects the power supply to avoid damaging the load electrical appliance and extend the service life of the load electrical appliance.

[0033] Among them, the above preset time of 2 seconds and the high level duration of 50 milliseconds are the numerical values of an embodiment of this case, and the preset time and the high level duration can be set to other values according to actual applications.

[0034] As Figure 1-2 shown, the MCU control circuit 6 is also connected to an MCU leakage signal detection circuit 10. The MCU leakage signal detection circuit 10 is connected to a thyristor SCR1, an LN line leakage detection control circuit 11 for detecting the leakage signal of the live wire or neutral wire at the output end 4, and a PE line fault current detection control circuit 12 for detecting the leakage signal of the ground wire at the output end 4. When the LN line leakage detection control circuit 11 or the PE line fault current detection control circuit 12 detects a leakage signal, the MCU leakage signal detection circuit 10 outputs the leakage signal to the MCU control circuit 6 and controls the thyristor SCR1 to conduct, so that the coil 3 is powered off and does not suck the switch 2. When there is no leakage, neither the LN line leakage detection control circuit 11 nor the PE line fault current detection control circuit 12 detects a leakage signal, the MCU leakage signal detection circuit 10 will not output a leakage signal to the MCU control circuit 6, and the MCU leakage signal detection circuit 10 controls the thyristor SCR1 to disconnect, maintaining the coil 3 energized to suck the switch 2.

[0035] As Figure 1-2As shown, the MCU control circuit 6 is connected to an over-temperature detection circuit 17 for detecting the temperature of the live or neutral pin, and an over-temperature protection control circuit 9 for outputting an analog leakage signal when the pin temperature exceeds the set temperature. The live wire at the output terminal 4 is connected to a TEST analog leakage circuit 15 for manually testing and outputting an analog leakage signal. When the LN wire leakage detection and control circuit 11 detects the analog leakage signal from the over-temperature protection control circuit 9 or the TEST analog leakage circuit 15, the MCU leakage signal detection circuit 10 outputs the analog leakage signal to the MCU control circuit 6 and controls the thyristor SCR1 to conduct, so that the coil 3 is powered off and does not attract the switch 2. When the pin temperature is lower than the set temperature and the user does not press the test switch TEST, the over-temperature protection control circuit 9 and the TEST analog leakage circuit 15 do not output an analog leakage signal, and the MCU leakage signal detection circuit 10 will not output an analog leakage signal to the MCU control circuit 6. The MCU leakage signal detection circuit 10 controls the thyristor SCR1 to disconnect, maintaining the coil 3 energized to attract the switch 2.

[0036] When the LN wire leakage detection and control circuit 11 or the PE wire fault current detection and control circuit 12 detects a leakage signal, the MCU leakage signal detection circuit 10 transmits the received leakage signal to the MCU control circuit 6, and at the same time controls the thyristor SCR1 to conduct, so that the coil 3 is powered off and does not attract the switch 2. The switch 2 disconnects the input power supply, and the MCU control circuit 6 controls the TEST key and the leakage alarm prompt circuit 19 to emit light to give an alarm prompt. After the user checks and handles the leakage accident, the leakage signal disappears. The MCU leakage signal detection circuit 10 controls the thyristor SCR1 to disconnect. The user must manually press the reset switch RESET of the power-on reset circuit 18. After the MCU control circuit 6 receives the reset signal of the power-on reset circuit 18, it outputs a high level to drive the coil large current attraction circuit 7 to output a large current to make the coil 3 energized to attract the switch 2. The coil small current attraction circuit 8 outputs a small current to maintain the coil 3 energized to attract the switch 2. The MCU control circuit 6 controls the TEST key and the leakage alarm prompt circuit 19 not to emit light to complete the reset power-on. When neither the LN wire leakage detection and control circuit 11 nor the PE wire fault current detection and control circuit 12 detects a leakage signal, the MCU leakage signal detection circuit 10 will not output a leakage signal to the MCU control circuit 6. The MCU leakage signal detection circuit 10 controls the thyristor SCR1 to disconnect, maintaining the coil 3 energized to attract the switch 2.

[0037] As Figure 1-2As shown, a ground fault indication circuit 13 that emits light when the ground wire is energized is connected between the neutral wire and the ground wire of the power supply terminal 1. When the ground wire of the power supply terminal 1 is properly grounded, the ground fault indication circuit 13 does not emit light. A power indication circuit 14 that emits light when the live wire of the output terminal 4 is energized is connected between the live wire of the output terminal 4 and the neutral wire of the power supply terminal 1. When the live wire of the output terminal 4 is not energized, the power indication circuit 14 does not emit light. The MCU control circuit 6 is connected to a TEST and leakage alarm indication circuit 19 that emits light when a leakage occurs. When no leakage occurs, the TEST and leakage alarm indication circuit 19 does not emit light. The MCU control circuit 6 is connected to a power-on reset circuit 18 for manual reset. After the user checks and eliminates the leakage accident, pressing the reset switch RESET realizes reset and power-on. The MCU control circuit 6 is powered by an MCU control power resistor-capacitor step-down circuit 16, and the LN line leakage detection and control circuit 11 and the PE line fault current detection and control circuit 12 are powered by a leakage control power resistor-capacitor step-down circuit 20. The coil small current suction circuit 8, the MCU control power resistor-capacitor step-down circuit 16, and the leakage control power resistor-capacitor step-down circuit 20 all adopt resistor-capacitor step-down circuits, which are beneficial to reducing the heat generation during operation, reducing the power consumption during standby, and being green and environmentally friendly.

[0038] As Figure 2 shown, the specific structure of the power supply anti-shake detection circuit 5 is as follows: The power supply anti-shake detection circuit 5 includes a triode Q2. The emitter of the triode Q2 is electrically connected to the neutral wire of the power supply terminal 1. The base of the triode Q2 is electrically connected to one end of a resistor 26 and one end of a resistor 27. The other end of the resistor 26 is electrically connected to one end of a resistor R14. The other end of the resistor R14 is electrically connected to the live wire of the power supply terminal 1. The other end of the resistor R27 is electrically connected to the neutral wire of the power supply terminal 1. The collector of the triode Q2 is electrically connected to the pin P00 of the MCU control circuit 6. The power supply anti-shake detection circuit 5 can process the voltage waveform of the input power supply in real time and output the processed input power supply voltage waveform to the MCU control circuit 6, so that the voltage waveform can meet the electrical reception requirements of the pin P00 of the MCU control circuit 6.

[0039] As Figure 2As shown in the figure, the specific structure of the coil high-current suction circuit 7 is as follows: The coil high-current suction circuit 7 includes a microcontroller unit U2. One end of the pin LED+ of the microcontroller unit U2 is electrically connected to one end of a resistor R11. The other end of the resistor R11 is electrically connected to the pin P01 of the MCU control circuit 6. The pin LED- of the microcontroller unit U2 is electrically connected to the neutral wire of the power supply terminal 1. The pin Terminal1 of the microcontroller unit U2 is electrically connected to one end of the coil 3. The pin Terminal2 of the microcontroller unit U2 is electrically connected to the negative electrode of a diode D9. The positive electrode of the diode D9 is electrically connected to one end of a resistor R15. The other end of the resistor R15 is electrically connected to the live wire of the power supply terminal 1. The other end of the coil 3 is electrically connected to the neutral wire of the power supply terminal 1. The coil high-current suction circuit 7 can receive the high level output by the MCU control circuit 6 and output a large current during the duration of the high level, so that the coil 3 completes the action of sucking the switch 2 under the drive of the large current. When the MCU control circuit 6 stops outputting the high level to the coil high-current suction circuit 7, the coil high-current suction circuit 7 no longer outputs a large current to the coil 3. Instead, the coil low-current suction circuit 8 outputs a small current to maintain the coil 3 to energize and suck the switch 2, avoiding excessive power consumption and increased heat generation caused by the coil high-current suction circuit 7 outputting a large current for a long time, reducing the power loss during standby, and being green and environmentally friendly.

[0040] As Figure 2 shown in the figure, the specific structure of the coil low-current suction circuit 8 is as follows: The coil low-current suction circuit 8 includes a resistor R1A. One end of the resistor R1A is electrically connected to one end of a resistor R1B. The other end of the resistor R1B is electrically connected to one end of a capacitor C1 and the live wire of the power supply terminal 1. The other end of the resistor R1A is electrically connected to the other end of the capacitor C1, the negative electrode of a diode D5, and the positive electrode of a diode D7. The positive electrode of the diode D5 is electrically connected to the neutral wire of the power supply terminal 1, the negative electrode of a polarized capacitor C6, and one end of the coil 3. The negative electrode of the diode D7 is electrically connected to the positive electrode of the polarized capacitor C6 and the other end of the coil 3. After the coil 3 completes the action of sucking the switch 2, the coil low-current suction circuit 8 outputs a small current to maintain the coil 3 to energize and suck the switch 2. The coil low-current suction circuit 8 adopts the structural mode of a resistor-capacitor step-down circuit, with a small output current. While realizing long-term maintenance of the coil 3 to energize and suck the switch 2, it can reduce the heat generation during operation, reduce the power loss during standby, and be green and environmentally friendly.

[0041] As Figure 2As shown, the specific structure of the MCU leakage signal detection circuit 10 is as follows: The MCU leakage signal detection circuit 10 includes a triode Q5. The collector of the triode Q5 is electrically connected to one end of a resistor R6 and the pin P02 of the MCU control circuit 6. The other end of the resistor R6 is electrically connected to the pin VDD of the MCU control circuit 6. The emitter of the triode Q5 is electrically connected to one end of a capacitor C19 and the neutral line of the power supply terminal 1. The base of the triode Q5 is electrically connected to the other end of the capacitor C19 and one end of a resistor R9. The other end of the resistor R9 is electrically connected to one end of a resistor R12 and the output terminal of a dual-way switch diode Q3. One input terminal of the dual-way switch diode Q3 is electrically connected to the pin SCR of the micro-control unit U1 of the LN line leakage detection control circuit 11. The other input terminal of the dual-way switch diode Q3 is electrically connected to the pin SCR of the micro-control unit U1E of the PE line fault current detection control circuit 12. The other end of the resistor R12 is electrically connected to one end of a capacitor C7 and the control electrode of the thyristor SCR1. The other end of the capacitor C7 is electrically connected to the neutral line of the power supply terminal 1 and the negative electrode of the thyristor SCR1. The positive electrode of the thyristor SCR1 is electrically connected to one end of the coil 3.

[0042] As Figure 2As shown, the specific structure of the LN line leakage detection and control circuit 11 is as follows: The LN line leakage detection and control circuit 11 includes a micro-control unit U1. One end of the pin Neutral of the micro-control unit U1 is electrically connected to one end of the capacitor C11 and the neutral line of the power supply terminal 1. One end of the pin Line of the micro-control unit U1 is electrically connected to one end of the resistor R2 of the leakage control power capacitive voltage reduction circuit 20 and one end of the capacitor C8. The other end of the capacitor C8 is electrically connected to the neutral line of the power supply terminal 1. One end of the pin VREF of the micro-control unit U1 is electrically connected to the other end of the capacitor C11, one end of the capacitor C9, one end of the resistor R16, and one end of the zero-sequence current transformer ZCT1. The other end of the zero-sequence current transformer ZCT1 is electrically connected to the other end of the resistor R16, the other end of the capacitor C9, and one end of the resistor R17. The other end of the resistor R17 is electrically connected to one end of the capacitor C10, one end of the resistor R18, and the pin VFB of the micro-control unit U1. One end of the pin AmpOUT of the micro-control unit U1 is electrically connected to the other end of the capacitor C10 and the other end of the resistor R18. The live wire and the neutral line of the output terminal 4, the connecting wire between the emitter of the triode Q1 of the overtemperature protection control circuit 9 and the neutral line of the power supply terminal 1, and the connecting wire between the test switch TEST of the TEST simulated leakage circuit 15 and the live wire of the output terminal 4 all pass through the center of the zero-sequence current transformer ZCT1. When the live wire or the neutral line of the output terminal 4 leaks electricity, the zero-sequence current transformer ZCT1 generates an induced current, and the micro-control unit U1 outputs the leakage signal to the MCU leakage signal detection circuit 10.

[0043] As Figure 2As shown in the figure, the specific structure of the PE line fault current detection and control circuit 12 is as follows: The PE line fault current detection and control circuit 12 includes a micro control unit U1E. One end of the pin Neutral of the micro control unit U1E is electrically connected to one end of the capacitor C14 and the neutral line of the power supply terminal 1. One end of the pin Line of the micro control unit U1E is electrically connected to one end of the resistor R2 and one end of the capacitor C8 of the leakage control power capacitive voltage reduction circuit 20. One end of the pin VREF of the micro control unit U1E is electrically connected to the other end of the capacitor C14, one end of the capacitor C13, one end of the resistor R20, and one end of the zero-sequence current transformer ZCT2. The other end of the zero-sequence current transformer ZCT2 is electrically connected to the other end of the resistor R20, the other end of the capacitor C13, and one end of the resistor R21. The other end of the resistor R21 is electrically connected to one end of the capacitor C12, one end of the resistor R19, and the pin VFB of the micro control unit U1E. One end of the pin AmpOUT of the micro control unit U1E is electrically connected to the other end of the capacitor C12 and the other end of the resistor R19. The ground wire of the output terminal 4 passes through the center of the zero-sequence current transformer ZCT2. When the ground wire of the output terminal 4 fails and becomes energized, the zero-sequence current transformer ZCT2 generates an induced current, and the micro control unit U1E outputs a leakage signal to the MCU leakage signal detection circuit 10.

[0044] As Figure 2 As shown in the figure, the over-temperature detection circuit 17 includes a thermistor R3. One end of the thermistor R3 is electrically connected to the neutral line of the power supply terminal 1 and one end of the capacitor C5. The other end of the thermistor R3 is electrically connected to one end of the resistor R4 and one end of the resistor R5. The other end of the resistor R4 is electrically connected to the pin VDD of the MCU control circuit 6. The other end of the resistor R5 is electrically connected to the pin P03 of the MCU control circuit 6 and the other end of the capacitor C5. The over-temperature protection control circuit 9 includes a triode Q1. The collector of the triode Q1 is electrically connected to one end of the resistor R15B. The other end of the resistor R15B is electrically connected to one end of the resistor R15A. The other end of the resistor R15A is electrically connected to the negative electrode of the diode D8. The positive electrode of the diode D8 is electrically connected to the live wire of the power supply terminal 1. The emitter of the triode Q1 is electrically connected to the neutral line of the power supply terminal 1. The base of the triode Q1 is electrically connected to one end of the resistor R28 and one end of the resistor R7. The other end of the resistor R28 is electrically connected to the neutral line of the power supply terminal 1. The other end of the resistor R7 is electrically connected to the pin P05 of the MCU control circuit 6.

[0045] The over-temperature detection circuit 17 transmits the detected pin temperature of the live wire or the neutral wire to the MCU control circuit 6. When the pin temperature exceeds the set temperature, the MCU control circuit 6 controls the over-temperature protection control circuit 9 to conduct, and the zero-sequence current transformer ZCT1 generates an induced current. The micro-control unit U1 outputs the leakage signal to the MCU leakage signal detection circuit 10. The MCU leakage signal detection circuit 10 transmits the received leakage signal to the MCU control circuit 6, and at the same time controls the thyristor SCR1 to conduct, so that the coil 3 is powered off and does not attract the switch 2, and the switch 2 disconnects the input power supply. When the pin temperature drops below the set temperature, the MCU control circuit 6 controls the over-temperature protection control circuit 9 to disconnect, the leakage signal disappears, the MCU leakage signal detection circuit 10 controls the thyristor SCR1 to disconnect, and the MCU control circuit 6 outputs a high level to drive the coil large-current attracting circuit 7 to output a large current to make the coil 3 get powered on and attract the switch 2, and the coil small-current attracting circuit 8 outputs a small current to maintain the coil 3 powered on and attracting the switch 2, and the switch 2 connects the input power supply. When the voltage waveform of the input power supply is not a sine wave, the MCU control circuit 6 can use the over-temperature protection control circuit 9 to conduct to generate an analog leakage signal to actively disconnect the input power supply, avoid damaging the load electrical appliance, and extend the service life of the load electrical appliance.

[0046] As Figure 2 shown, the TEST analog leakage circuit 15 includes a test switch TEST. One end of the test switch TEST is electrically connected to the live wire of the output terminal 4, and the other end of the test switch TEST is electrically connected to one end of the resistor R9B. The other end of the resistor R9B is electrically connected to one end of the resistor R9A, and the other end of the resistor R9A is electrically connected to the neutral wire of the power supply terminal 1. When the user presses the test switch TEST, the TEST analog leakage circuit 15 conducts, the zero-sequence current transformer ZCT1 generates an induced current, the micro-control unit U1 outputs the leakage signal to the MCU leakage signal detection circuit 10. The MCU leakage signal detection circuit 10 transmits the received leakage signal to the MCU control circuit 6, and at the same time controls the thyristor SCR1 to conduct, so that the coil 3 is powered off and does not attract the switch 2, and the switch 2 disconnects the input power supply. The MCU control circuit 6 controls the TEST key and the leakage alarm prompt circuit 19 to emit light and issue an alarm prompt. The user must manually press the reset switch RESET of the power-on reset circuit 18. After the MCU control circuit 6 receives the reset signal of the power-on reset circuit 18, it outputs a high level to drive the coil large-current attracting circuit 7 to output a large current to make the coil 3 get powered on and attract the switch 2, and the coil small-current attracting circuit 8 outputs a small current to maintain the coil 3 powered on and attracting the switch 2. The MCU control circuit 6 controls the TEST key and the leakage alarm prompt circuit 19 not to emit light to complete the reset power-on.

Claims

1. A control circuit for a leakage protection switch device, characterized in that: It includes a power supply terminal (1) connected to an input power supply, an output terminal (4) connected to a load, and an MCU control circuit (6). A switch (2) controlled by a coil (3) is connected to the live wire, neutral wire, and ground wire between the power supply terminal (1) and the output terminal (4). The MCU control circuit (6) is connected to a power supply anti-shake detection circuit (5) for detecting the positive and negative cycle voltage waveforms of the input power supply, and a coil large current suction circuit (7) for outputting a large current to energize the coil (3) to attract the switch (2) when the power supply anti-shake detection circuit (5) detects that the input power supply voltage waveform is a sine wave within a preset time. The power supply terminal (1) is connected to a coil small current suction circuit (8) for maintaining the coil (3) energized and attracted after the coil (3) attracts the switch (2); The MCU control circuit (6) is also connected to an MCU leakage signal detection circuit (10). The MCU leakage signal detection circuit (10) is connected to a thyristor SCR1, an LN line leakage detection and control circuit (11) for detecting the leakage signal of the live wire or neutral wire of the output terminal (4), and a PE line fault current detection and control circuit (12) for detecting the leakage signal of the ground wire of the output terminal (4). When the LN line leakage detection and control circuit (11) or the PE line fault current detection and control circuit (12) detects a leakage signal, the MCU leakage signal detection circuit (10) outputs the leakage signal to the MCU control circuit (6) and controls the thyristor SCR1 to conduct, so that the coil (3) is de-energized and does not attract the switch (2); The MCU control circuit (6) is connected to an over-temperature detection circuit (17) for detecting the temperature of the live wire or neutral wire pin, and an over-temperature protection control circuit (9) for outputting an analog leakage signal when the pin temperature exceeds the set temperature. The live wire of the output terminal (4) is connected to a TEST analog leakage circuit (15) for manually testing and outputting an analog leakage signal. When the LN line leakage detection and control circuit (11) detects the analog leakage signal of the over-temperature protection control circuit (9) or the TEST analog leakage circuit (15), the MCU leakage signal detection circuit (10) outputs the analog leakage signal to the MCU control circuit (6) and controls the thyristor SCR1 to conduct, so that the coil (3) is de-energized and does not attract the switch (2); An abnormal grounding indication circuit (13) that emits light when the ground wire is energized is connected between the neutral wire and the ground wire of the power supply terminal (1). A power supply indication circuit (14) that emits light when the live wire of the output terminal (4) is energized is connected between the live wire of the output terminal (4) and the neutral wire of the power supply terminal (1).

2. The control circuit of a leakage protection switch device according to claim 1, characterized in that: The MCU control circuit (6) is powered by the MCU control power resistor-capacitor step-down circuit (16). The MCU control circuit (6) is connected to a power-on reset circuit (18) for manual reset, and a TEST and leakage alarm indication circuit (19) for emitting light during leakage. The LN line leakage detection and control circuit (11) and the PE line fault current detection and control circuit (12) are powered by the leakage control power resistor-capacitor step-down circuit (20).

3. The control circuit of a leakage protection switch device according to claim 1, characterized in that: The power anti-shake detection circuit (5) includes a triode Q2. The emitter of the triode Q2 is electrically connected to the neutral line of the power supply terminal (1). The base of the triode Q2 is electrically connected to one end of a resistor R26 and one end of a resistor R27. The other end of the resistor R26 is electrically connected to one end of a resistor R14. The other end of the resistor R14 is electrically connected to the live wire of the power supply terminal (1). The other end of the resistor R27 is electrically connected to the neutral line of the power supply terminal (1). The collector of the triode Q2 is electrically connected to the pin P00 of the MCU control circuit (6).

4. The control circuit of a leakage protection switch device according to claim 1, characterized in that: The coil large current attraction circuit (7) includes a micro control unit U2. The pin LED+ of the micro control unit U2 is electrically connected to one end of a resistor R11. The other end of the resistor R11 is electrically connected to the pin P01 of the MCU control circuit (6). The pin LED- of the micro control unit U2 is electrically connected to the neutral line of the power supply terminal (1). The pin Terminal1 of the micro control unit U2 is electrically connected to one end of the coil (3). The pin Terminal2 of the micro control unit U2 is electrically connected to the negative electrode of a diode D9. The positive electrode of the diode D9 is electrically connected to one end of a resistor R15. The other end of the resistor R15 is electrically connected to the live wire of the power supply terminal (1). The other end of the coil (3) is electrically connected to the neutral line of the power supply terminal (1).

5. The control circuit of a leakage protection switch device according to claim 1, characterized in that: The small current attraction circuit (8) includes a resistor R1A. One end of the resistor R1A is electrically connected to one end of a resistor R1B. The other end of the resistor R1B is electrically connected to one end of a capacitor C1 and the live wire of the power supply terminal (1). The other end of the resistor R1A is electrically connected to the other end of the capacitor C1, the negative electrode of a diode D5, and the positive electrode of a diode D7. The positive electrode of the diode D5 is electrically connected to the neutral line of the power supply terminal (1), the negative electrode of a polarized capacitor C6, and one end of the coil (3). The negative electrode of the diode D7 is electrically connected to the positive electrode of the polarized capacitor C6 and the other end of the coil (3).

6. The control circuit of a leakage protection switch device according to claim 1, characterized in that: The MCU leakage signal detection circuit (10) includes a triode Q5. The collector of the triode Q5 is electrically connected to one end of a resistor R6 and the pin P02 of the MCU control circuit (6). The other end of the resistor R6 is electrically connected to the pin VDD of the MCU control circuit (6). The emitter of the triode Q5 is electrically connected to one end of a capacitor C19 and the neutral line of the power supply terminal (1). The base of the triode Q5 is electrically connected to the other end of the capacitor C19 and one end of a resistor R9. The other end of the resistor R9 is electrically connected to one end of a resistor R12 and the output terminal of a dual-way switch diode Q3. One input terminal of the dual-way switch diode Q3 is electrically connected to the pin SCR of the micro control unit U1 of the LN line leakage detection control circuit (11). The other input terminal of the dual-way switch diode Q3 is electrically connected to the pin SCR of the micro control unit U1E of the PE line fault current detection control circuit (12). The other end of the resistor R12 is electrically connected to one end of a capacitor C7 and the control electrode of the thyristor SCR1. The other end of the capacitor C7 is electrically connected to the neutral line of the power supply terminal (1) and the negative electrode of the thyristor SCR1. The positive electrode of the thyristor SCR1 is electrically connected to one end of the coil (3).

7. The control circuit of a leakage protection switch device according to claim 2, characterized in that: The LN line leakage detection and control circuit (11) includes a micro control unit U1. The Neutral pin of the micro control unit U1 is electrically connected to one end of a capacitor C11 and the neutral line of the power supply terminal (1). The Line pin of the micro control unit U1 is electrically connected to one end of a resistor R2 and one end of a capacitor C8 of the leakage control power capacitive voltage reduction circuit (20). The other end of the capacitor C8 is electrically connected to the neutral line of the power supply terminal (1). The VREF pin of the micro control unit U1 is electrically connected to the other end of the capacitor C11, one end of a capacitor C9, one end of a resistor R16, and one end of a zero-sequence current transformer ZCT1. The other end of the zero-sequence current transformer ZCT1 is electrically connected to the other end of the resistor R16, the other end of the capacitor C9, and one end of a resistor R17. The other end of the resistor R17 is electrically connected to one end of a capacitor C10, one end of a resistor R18, and the VFB pin of the micro control unit U1. The AmpOUT pin of the micro control unit U1 is electrically connected to the other end of the capacitor C10 and the other end of the resistor R18. The live wire and neutral line of the output terminal (4), the connection line between the emitter of the triode Q1 of the overtemperature protection control circuit (9) and the neutral line of the power supply terminal (1), and the connection line between the test switch TEST of the TEST analog leakage circuit (15) and the live wire of the output terminal (4) all pass through the center of the zero-sequence current transformer ZCT1. The PE line fault current detection and control circuit (12) includes a micro control unit U1E. The Neutral pin of the micro control unit U1E is electrically connected to one end of a capacitor C14 and the neutral line of the power supply terminal (1). The Line pin of the micro control unit U1E is electrically connected to one end of a resistor R2 and one end of a capacitor C8 of the leakage control power capacitive voltage reduction circuit (20). The VREF pin of the micro control unit U1E is electrically connected to the other end of the capacitor C14, one end of a capacitor C13, one end of a resistor R20, and one end of a zero-sequence current transformer ZCT2. The other end of the zero-sequence current transformer ZCT2 is electrically connected to the other end of the resistor R20, the other end of the capacitor C13, and one end of a resistor R21. The other end of the resistor R21 is electrically connected to one end of a capacitor C12, one end of a resistor R19, and the VFB pin of the micro control unit U1E. The AmpOUT pin of the micro control unit U1E is electrically connected to the other end of the capacitor C12 and the other end of the resistor R19. The ground wire of the output terminal (4) passes through the center of the zero-sequence current transformer ZCT2.

8. The control circuit of a leakage protection switch device according to claim 2, characterized in that: The over-temperature detection circuit (17) includes a thermistor R3. One end of the thermistor R3 is electrically connected to the neutral wire of the power supply terminal (1) and one end of a capacitor C5. The other end of the thermistor R3 is electrically connected to one end of a resistor R4 and one end of a resistor R5. The other end of the resistor R4 is electrically connected to the pin VDD of the MCU control circuit (6). The other end of the resistor R5 is electrically connected to the pin P03 of the MCU control circuit (6) and the other end of the capacitor C5. The over-temperature protection control circuit (9) includes a triode Q1. The collector of the triode Q1 is electrically connected to one end of a resistor R15B. The other end of the resistor R15B is electrically connected to one end of a resistor R15A. The other end of the resistor R15A is electrically connected to the negative electrode of a diode D8. The positive electrode of the diode D8 is electrically connected to the live wire of the power supply terminal (1). The emitter of the triode Q1 is electrically connected to the neutral wire of the power supply terminal (1). The base of the triode Q1 is electrically connected to one end of a resistor R28 and one end of a resistor R7. The other end of the resistor R28 is electrically connected to the neutral wire of the power supply terminal (1). The other end of the resistor R7 is connected to the pin P05 of the MCU control circuit (6). The TEST analog leakage circuit (15) includes a test switch TEST. One end of the test switch TEST is electrically connected to the live wire of the output terminal (4). The other end of the test switch TEST is electrically connected to one end of a resistor R9B. The other end of the resistor R9B is electrically connected to one end of a resistor R9A. The other end of the resistor R9A is electrically connected to the neutral wire of the power supply terminal (1).

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