Electric leakage rapid detection circuit

Abstract

The utility model discloses an electric leakage rapid detection circuit, which comprises an electric leakage detection unit, a voltage amplification unit, a comparison unit, a reference voltage regulation unit and a reference voltage stabilization unit, the electric leakage detection unit is used for detecting electric leakage voltage, and the output end of the electric leakage detection unit is electrically connected with the voltage amplification unit. The output end of the voltage amplification unit is electrically connected with one input end of the comparison unit, the reference voltage stabilizing unit is electrically connected with the reference voltage adjusting unit, and the reference voltage stabilizing unit and the reference voltage adjusting unit are jointly and electrically connected with the other input end of the comparison unit. The output end of the comparison unit is used for being electrically connected with an external controller. According to the utility model, the leakage current can be adjusted, and the leakage protection speed can be improved.

Description

Technical Field

[0001] The utility model relates to the field of leakage detection circuits, and particularly to a rapid leakage detection circuit. Background Art

[0002] A leakage protector switch, also known as a residual current circuit breaker or a leakage switch, is an important electrical safety device. Its main function is to provide protection when a leakage fault occurs in the device and in the case of a fatal electric shock to a person. In addition, it also has overload and short-circuit protection functions, and can be used to protect the overload and short-circuit of a line or a motor. Even under normal circumstances, it can also be used for the infrequent conversion and startup of a line.

[0003] The traditional leakage protector switch takes effect in 100mS, and the leakage current needs to reach 30mA to operate. If it is lower than 30mA, it will not operate. However, when the leakage current exceeds 10mA, the human body will have an obvious sense of electric shock. An adult can get rid of it through perception, but if a child gets an electric shock and has no ability to get rid of it, it is more dangerous and likely to endanger personal safety, reducing the safety of the protector. Summary of the Invention

[0004] The purpose of the utility model is to overcome the deficiencies in the prior art and provide a rapid leakage detection circuit that can adjust the magnitude of the leakage current and improve the leakage protection speed.

[0005] The purpose of the utility model is achieved by the following technical solutions:

[0006] A rapid leakage detection circuit includes: a leakage detection unit, a voltage amplification unit, a comparison unit, a reference voltage adjustment unit, and a reference voltage stabilization unit. The leakage detection unit is used to detect the leakage voltage. The output end of the leakage detection unit is electrically connected to the voltage amplification unit. The output end of the voltage amplification unit is electrically connected to one input end of the comparison unit. The reference voltage stabilization unit is electrically connected to the reference voltage adjustment unit. The reference voltage stabilization unit and the reference voltage adjustment unit are also commonly electrically connected to the other input end of the comparison unit. The output end of the comparison unit is used to be electrically connected to an external controller.

[0007] In one embodiment, the leakage detection unit includes a resistor R1, a resistor R2, a resistor R4, a resistor R9, and a differential comparator U1.1. The resistor R1 and the resistor R2 are commonly connected to the non-inverting input end of the differential comparator U1.1. The resistor R4 and the resistor R9 are commonly connected to the inverting input end of the differential comparator U1.1. The output end of the differential comparator U1.1 is electrically connected to the voltage amplification unit.

[0008] In one embodiment, the voltage amplification unit includes a resistor R20, a resistor R21, a slide rheostat R15, and a voltage amplifier U1.2. One end of the resistor R21 is electrically connected to the output end of the leakage detection unit, and the other end of the resistor R21 is electrically connected to the non-inverting input end of the voltage amplifier U1.2. The resistor R20 is respectively electrically connected to the slide rheostat R15 and the inverting input end of the voltage amplifier U1.2. The output end of the voltage amplifier U1.2 is electrically connected to the comparison unit.

[0009] In one embodiment, the comparison unit includes a zener diode D3, a resistor R10, a resistor R18, and a comparison chip U3. One end of the resistor R18 is electrically connected to the VCC power supply, and the other end of the resistor R18 is respectively electrically connected to the resistor R10 and the output end of the comparison chip U3. The other end of the resistor R10 is electrically connected to the zener diode D3, and the other end of the resistor R10 is also used to output the regulated voltage. One input end of the comparison chip U3 is electrically connected to the output end of the voltage amplification unit.

[0010] In one embodiment, the reference voltage regulation unit includes a resistor R11, a resistor R12, and a zener diode U20. The resistor R11 is respectively electrically connected to the resistor R12 and the first end of the zener diode U20. The second end of the zener diode U20 is also electrically connected to the VCC power supply, and the second end of the zener diode U20 is also respectively electrically connected to the comparison unit and the reference voltage adjustment unit.

[0011] In one embodiment, the reference voltage adjustment unit includes a resistor R16 and a variable resistor R17. The resistor R16 is electrically connected to the variable resistor R17. The variable resistor R17 is respectively electrically connected to the comparison unit and the reference voltage regulation unit.

[0012] In one embodiment, the variable resistor R17 is a slide rheostat.

[0013] The advantages and beneficial effects of the present utility model compared with the prior art are as follows:

[0014] The utility model relates to a rapid leakage detection circuit. By setting a leakage detection unit, a voltage amplification unit, a comparison unit, a reference voltage adjustment unit and a reference voltage stabilization unit, when a leakage current signal is input from the leakage detection unit, the leakage current is differentially amplified and then compared with the reference voltage. When it is higher than the reference voltage, the comparison unit outputs a high level. The reference voltage stabilization unit is set for voltage stabilization. The final voltage signal is fed back from the output terminal I-fign of the comparison unit. When the MCU detects the voltage signal at the output terminal I-fign of the comparison unit, it immediately drives an IGBT or MOSFET tube to quickly cut off the power supply, so that the magnitude of the leakage current can be adjusted and the leakage protection speed can be improved. In addition, the leakage detection part adopts a differential input mode, which can effectively remove interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic block diagram of a rapid leakage detection circuit according to an embodiment of the utility model;

[0016] Figure 2 is Figure 1 the circuit diagram of the rapid leakage detection circuit shown;

[0017] Figure 3 is Figure 1 the circuit diagram of the rapid leakage detection circuit shown;

[0018] Figure 4 is Figure 1 the circuit diagram of the rapid leakage detection circuit shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To facilitate the understanding of the utility model, the utility model will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the utility model are shown in the drawings. However, the utility model can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the utility model more thorough and comprehensive.

[0020] Please refer to Figures 1 to 4 , a rapid leakage detection circuit, comprising: a leakage detection unit, a voltage amplification unit, a comparison unit, a reference voltage adjustment unit and a reference voltage stabilization unit. The leakage detection unit is used to detect the leakage voltage. The output terminal of the leakage detection unit is electrically connected to the voltage amplification unit. The output terminal of the voltage amplification unit is electrically connected to an input terminal of the comparison unit. The reference voltage stabilization unit is electrically connected to the reference voltage adjustment unit. The reference voltage stabilization unit and the reference voltage adjustment unit are also commonly electrically connected to another input terminal of the comparison unit. The output terminal of the comparison unit is used to be electrically connected to an external controller.

[0021] Thus, by setting up a leakage current detection unit, a voltage amplification unit, a comparison unit, a reference voltage adjustment unit, and a reference voltage stabilization unit, after the leakage current signal is input from the leakage current detection unit, the leakage current is differentially amplified and then compared with the reference voltage. When it is higher than the reference voltage, the comparison unit outputs a high level. The reference voltage stabilization unit is set up for voltage stabilization. The final voltage signal is fed back from the output terminal I-fign of the comparison unit. When the MCU detects the voltage signal at the output terminal I-fign of the comparison unit, it immediately drives the IGBT or MOSFET tube to quickly cut off the power supply, thereby adjusting the magnitude of the leakage current and improving the leakage protection speed. In addition, the differential input method is adopted for the leakage current detection part, which can effectively remove interference.

[0022] Please refer to Figure 2 As shown in, the leakage current detection unit includes a resistor R1, a resistor R2, a resistor R4, a resistor R9, and a differential comparator U1.1. The resistors R1 and R2 are commonly connected to the non-inverting input terminal of the differential comparator U1.1, and the resistors R4 and R9 are commonly connected to the inverting input terminal of the differential comparator U1.1. The output terminal of the differential comparator U1.1 is electrically connected to the voltage amplification unit. Thus, positive and negative power supply interfaces are reserved at the input power supply interface, and the user can choose single power supply input or dual power supply input, which is convenient for the user to select power supply using the existing power supply module. The detection speed of the dual power supply can reach within 1 mS, and the slowest detection time for single power supply is 15 mS, which improves the detection speed. The differential input method is adopted for the leakage current detection part, which can effectively remove interference.

[0023] Please refer to Figure 3 As shown in, the voltage amplification unit includes a resistor R20, a resistor R21, a potentiometer R15, and a voltage amplifier U1.2. One end of the resistor R21 is electrically connected to the output terminal of the leakage current detection unit, and the other end of the resistor R21 is electrically connected to the non-inverting input terminal of the voltage amplifier U1.2. The resistor R20 is respectively connected to the potentiometer R15 and the inverting input terminal of the voltage amplifier U1.2. The output terminal of the voltage amplifier U1.2 is electrically connected to the comparison unit. Thus, the amplification of the voltage signal can be realized, and the amplification factor of the signal can be adjusted by the adjustable resistor R15 in the signal amplification part.

[0024] Please refer to Figure 4, the comparison unit includes a voltage stabilizing diode D3, a resistor R10, a resistor R18, and a comparison chip U3. One end of the resistor R18 is electrically connected to the VCC power supply, the other end of the resistor R18 is respectively electrically connected to the resistor R10 and the output end of the comparison chip U3, one end of the resistor R10 is electrically connected to the voltage stabilizing diode D3, and the other end of the resistor R10 is also used to output the stabilized voltage. One input end of the comparison chip U3 is electrically connected to the output end of the voltage amplification unit. In this way, the voltage stabilizing diode D3 is adopted at the feedback point, so that the feedback voltage will not exceed the highest voltage of the MCU pin, thereby protecting the MCU.

[0025] Please refer to Figure 4 , the reference voltage stabilizing unit includes a resistor R11, a resistor R12, and a voltage stabilizing diode U20. The resistor R11 is respectively electrically connected to the resistor R12 and the first end of the voltage stabilizing diode U20. The second end of the voltage stabilizing diode U20 is also electrically connected to the VCC power supply, and the second end of the voltage stabilizing diode U20 is also respectively electrically connected to the comparison unit and the reference voltage adjusting unit. In this way, the voltage of VCC2 is stabilized by the voltage stabilizing diode U20, the stability of the reference power supply voltage is improved, and the influence of the unstable input power supply voltage on the voltage of the reference power supply is prevented.

[0026] Please refer to Figure 4 , the reference voltage adjusting unit includes a resistor R16 and a variable resistor R17. The resistor R16 is electrically connected to the variable resistor R17, and the variable resistor R17 is respectively electrically connected to the comparison unit and the reference voltage stabilizing unit. In this embodiment, the variable resistor R17 is a sliding rheostat. In this way, the leakage reference voltage adjusting part can calculate the setting of the reference voltage through the turns ratio and amplification factor of the mutual inductor, and the reference voltage can be adjusted by R17.

[0027] When the leakage current signal is input from IP-IN in the present invention, the signal is differentially amplified and then compared with the reference voltage at the CN1 point. When it is higher than the reference voltage at the CN1 point, the U3-1OUT outputs a high level. Voltage stabilization is performed through R10 and D3. The signal is fed back from I-fign. When the MCU detects the signal of I-fign, it immediately drives the IGBT or MOSFET tube to quickly cut off the power supply.

[0028] The above-described embodiments only represent several embodiments of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A rapid leakage detection circuit, characterized in that: include: A leakage detection unit, a voltage amplification unit, a comparison unit, a reference voltage adjustment unit and a reference voltage stabilizing unit, wherein the leakage detection unit is used to detect leakage voltage, the output end of the leakage detection unit is electrically connected to the voltage amplification unit, the output end of the voltage amplification unit is electrically connected to an input end of the comparison unit, the reference voltage stabilizing unit is electrically connected to the reference voltage adjustment unit, the reference voltage stabilizing unit and the reference voltage adjustment unit are also electrically connected to another input end of the comparison unit, and the output end of the comparison unit is used to be electrically connected to an external controller.

2. The rapid leakage detection circuit according to claim 1, characterized in that: The leakage detection unit includes a resistor R1, a resistor R2, a resistor R4, a resistor R9 and a differential comparator U1.

1. The resistors R1 and R2 are commonly connected to the non-inverting input terminal of the differential comparator U1.1, the resistors R4 and R9 are commonly connected to the inverting input terminal of the differential comparator U1.1, and the output terminal of the differential comparator U1.1 is electrically connected to the voltage amplification unit.

3. The rapid leakage detection circuit according to claim 1, characterized in that: The voltage amplification unit includes a resistor R20, a resistor R21, a sliding rheostat R15 and a voltage amplifier U1.

2. One end of the resistor R21 is electrically connected to the output end of the leakage detection unit, and the other end of the resistor R21 is electrically connected to the in-phase input end of the voltage amplifier U1.

2. The resistor R20 is electrically connected to the sliding rheostat R15 and the inverting input end of the voltage amplifier U1.2 respectively, and the output end of the voltage amplifier U1.2 is electrically connected to the comparison unit.

4. The rapid leakage detection circuit according to claim 1, characterized in that: The comparison unit includes a voltage regulator tube D3, a resistor R10, a resistor R18 and a comparison chip U3. One end of the resistor R18 is electrically connected to the VCC power supply, and the other end of the resistor R18 is electrically connected to the resistor R10 and the output end of the comparison chip U3 respectively. The other end of the resistor R10 is electrically connected to the voltage regulator tube D3. The other end of the resistor R10 is also used to output the stabilized voltage. An input end of the comparison chip U3 is electrically connected to the output end of the voltage amplification unit.

5. The rapid leakage detection circuit according to claim 1, characterized in that: The reference voltage stabilizing unit includes a resistor R11, a resistor R12 and a zener diode U20, wherein the resistor R11 is electrically connected to the resistor R12 and a first end of the zener diode U20 respectively, the second end of the zener diode U20 is also electrically connected to a VCC power supply, and the second end of the zener diode U20 is also electrically connected to the comparison unit and the reference voltage adjustment unit respectively.

6. The rapid leakage detection circuit according to claim 1, characterized in that: The reference voltage adjustment unit includes a resistor R16 and an adjustable resistor R17, the resistor R16 is electrically connected to the adjustable resistor R17, and the adjustable resistor R17 is electrically connected to the comparison unit and the reference voltage stabilization unit respectively.

7. The rapid leakage detection circuit according to claim 6, characterized in that: The adjustable resistor R17 is a sliding resistor.

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