CN204391679U - A kind of leakage current detection protection circuit - Google Patents

A kind of leakage current detection protection circuit Download PDF

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Publication number
CN204391679U
CN204391679U CN201520063312.7U CN201520063312U CN204391679U CN 204391679 U CN204391679 U CN 204391679U CN 201520063312 U CN201520063312 U CN 201520063312U CN 204391679 U CN204391679 U CN 204391679U
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circuit
leakage current
resistance
current
detection protection
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CN201520063312.7U
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Chinese (zh)
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梁宇
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Guangdong East Power Co Ltd
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Guangdong East Power Co Ltd
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Abstract

A kind of leakage current detection protection circuit, relate to electric leakage protection technology field, its circuit comprises current-voltage conversion processing circuit, comparison circuit, switching tube and external indicating circuit, current-voltage conversion processing circuit gathers the leakage current of wire pair ground wire to be measured, this leakage current is converted to voltage signal A by current-voltage conversion processing circuit, this voltage signal A is inputed to an input of comparison circuit, another input of comparison circuit is reference voltage signal B, when A is greater than B, comparison circuit exports a kind of signal makes switching tube conducting to drive external indicating circuit work, when A is less than B, comparison circuit exports another signal makes switching tube cut-off that external indicating circuit is not worked, externally prompting can be sent when electric wire to be measured leakage current over the ground exceeds preset value, make the external world can take measures in time to process the excessive problem of leakage current, electronic equipment can be protected better, prevent from causing electronic equipment aging because leaking electricity for a long time.

Description

A kind of leakage current detection protection circuit
Technical field
The utility model relates to electric leakage protection technology field, particularly relates to a kind of leakage current detection protection circuit.
Background technology
A lot of occasion, be all can not exceed certain safety value to the leakage current of ground wire to the requirement of electronic equipment, such as, in industry, regulation zero line N can not more than 3.5mA to the leakage current of ground wire PE, but, in prior art, a lot of electronic equipment does not have detection of electrical leakage, not can find leakage current, there is no telling leakage current is how many more, if generation leaky, circuit will be caused to generate heat and loss becomes large etc. when leakage current is excessive, leaking electricity for a long time to cause electronic equipment aging.
Summary of the invention
The purpose of this utility model is avoid weak point of the prior art and provide a kind of leakage current detection protection circuit; this leakage current detection protection circuit externally can send prompting when leakage current exceeds preset value; make the external world can take measures in time to process the excessive problem of leakage current; electronic equipment can being protected better, preventing from causing electronic equipment aging because leaking electricity for a long time.
The purpose of this utility model is achieved through the following technical solutions:
A kind of leakage current detection protection circuit is provided, comprise current-voltage conversion processing circuit, comparison circuit, switching tube and external indicating circuit, described current-voltage conversion processing circuit gathers the leakage current of wire pair ground wire to be measured, this leakage current is converted to voltage signal A by described current-voltage conversion processing circuit, this voltage signal A is inputed to an input of comparison circuit, another input of comparison circuit is reference voltage signal B, when A is greater than B, comparison circuit exports a kind of signal makes switching tube conducting to drive external indicating circuit work, when A is less than B, comparison circuit exports another signal makes switching tube cut-off that external indicating circuit is not worked.
Described current-voltage conversion processing circuit comprises Current Transmit 1, resistance RM, diode D1 and electric capacity C1, described comparison circuit is comparator U1, described switching tube comprises resistance R3 and triode Q1, described external indicating circuit comprises LED 1, two inputs connecting to neutral line N and ground wire PE respectively of described Current Transmit 1, one end of an output connecting resistance RM of described Current Transmit 1 and the positive pole of diode D1, the negative pole of described diode D1 connects the positive pole of described electric capacity C1 and the positive input terminal 11 of comparator U1, the negative pole of described electric capacity C1 connects the other end of described resistance RM, another output of described Current Transmit 1 and ground GND, the negative input end 10 of described comparator U1 meets power supply VCC, the power end 3 of described comparator U1 connects one end of power supply VCC and resistance R3, the output 13 of another termination comparator U1 of described resistance R3, the collector electrode of triode Q1 and the base stage of triode Q1, the emitter of described triode Q1 connects the positive pole of described LED 1, the minus earth GND of described LED 1.
Buzzer BZ1 is connected between the negative pole of described LED 1 and ground GND.
The turn ratio of described current transformer is 10:1, and the value of described resistance RM is 82.5 Ω.
Described resistance RM comprises resistance R1 and R2 of series connection.
The model of described comparator is LM339NG.
The model of described triode is MMBT2222A.
Described external indicating circuit is digital signal processing chip DSP.
The beneficial effects of the utility model: a kind of leakage current detection protection circuit of the present utility model comprises current-voltage conversion processing circuit, comparison circuit, switching tube and external indicating circuit, described current-voltage conversion processing circuit gathers the leakage current of wire pair ground wire to be measured, this leakage current is converted to voltage signal A by described current-voltage conversion processing circuit, this voltage signal A is inputed to an input of comparison circuit, another input of comparison circuit is reference voltage signal B, when A is greater than B, comparison circuit exports a kind of signal makes switching tube conducting to drive external indicating circuit work, when A is less than B, comparison circuit exports another signal makes switching tube cut-off that external indicating circuit is not worked, externally prompting can be sent when zero line leakage current over the ground exceeds preset value, make the external world can take measures in time to process the excessive problem of leakage current, electronic equipment can be protected better, prevent from causing electronic equipment aging because leaking electricity for a long time.
Accompanying drawing explanation
Accompanying drawing is utilized to be described further utility model, but the embodiment in accompanying drawing does not form any restriction of the present utility model, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to the following drawings.
Fig. 1 is the circuit diagram of the embodiment of a kind of leakage current detection protection circuit of the present utility model.
Embodiment
With the following Examples the utility model is further described.
A kind of leakage current detection protection circuit of the present embodiment, as shown in Figure 1, comprise current-voltage conversion processing circuit, comparison circuit, switching tube and external indicating circuit, described current-voltage conversion processing circuit comprises Current Transmit 1, resistance RM, diode D1 and electric capacity C1, described comparison circuit is comparator U1, described switching tube comprises resistance R3 and triode Q1, described external indicating circuit comprises LED 1, two inputs connecting to neutral line N and ground wire PE respectively of described Current Transmit 1, one end of an output connecting resistance RM of described Current Transmit 1 and the positive pole of diode D1, the negative pole of described diode D1 connects the positive pole of described electric capacity C1 and the positive input terminal 11 of comparator U1, the negative pole of described electric capacity C1 connects the other end of described resistance RM, another output of described Current Transmit 1 and ground GND, the negative input end 10 of described comparator U1 meets power supply VCC, the power end 3 of described comparator U1 connects one end of power supply VCC and resistance R3, the output 13 of another termination comparator U1 of described resistance R3, the collector electrode of triode Q1 and the base stage of triode Q1, the emitter of described triode Q1 connects the positive pole of described LED 1, the minus earth GND of described LED 1.
The turn ratio of current transformer is set to 10:1 by the present embodiment, according to computing formula: 3.5mA*10*0.001*RM*1.732=5V, then the value of resistance RM is set to 82.5 Ω, when the leakage current of zero line N to ground wire PE is less than 3.5mA, this leakage current is converted to voltage signal by Current Transmit 1 and resistance RM, by diode D1 rectification, after electric capacity C1 filtering, be input to 11 pin of comparator U1, 10 pin of comparator U1 are reference voltage 5V, now the voltage of 11 pin of comparator U1 is lower than the voltage of 10 pin, the 13 pin output low levels of comparator U1, triode Q1 not conducting, light-emitting diode does not work, otherwise, when the leakage current of zero line N to ground wire PE is greater than 3.5mA, this leakage current is converted to voltage signal by Current Transmit 1 and resistance RM, by diode D1 rectification, after electric capacity C1 filtering, be input to 11 pin of comparator U1, 10 pin of comparator U1 are reference voltage 5V, now the voltage of 11 pin of comparator U1 is higher than the voltage of 10 pin, 13 pin of comparator U1 export high level, triode Q1 conducting, lumination of light emitting diode, now leakage current excessive needs overhauls to inform staff, therefore, the leakage current detection protection circuit of the present embodiment externally can send prompting when zero line leakage current over the ground exceeds 3.5mA, make the external world can take measures in time to process the excessive problem of leakage current, electronic equipment can be protected better, prevent from causing electronic equipment aging because leaking electricity for a long time.
Certainly, the turn ratio of current transformer can be set to other value, accordingly, the value of resistance RM also can follow current instrument transformer turn ratio and change.
Further, buzzer BZ1 is connected between the negative pole of described LED 1 and ground GND, external electric leakage instruction can be strengthened further by the yowl of buzzer BZ1, now leakage current excessive needs overhauls to inform staff by the mode of sound, and staff more easily obtains electric leakage information.
Described resistance RM comprises resistance R1 and R2 of series connection.
The model of described comparator is LM339NG, and cost performance is high.
The model of described triode is MMBT2222A, and cost performance is high.
Certainly, described external indicating circuit can also be digital signal processing chip DSP, and the conducting of triode Q1 or cut-off export DSP to as two kinds of different signals, are controlled the operating state of electronic equipment, without the need to manual operation by DSP.
Finally should be noted that; above embodiment is only in order to illustrate the technical solution of the utility model; but not the restriction to the utility model protection range; although done to explain to the utility model with reference to preferred embodiment; those of ordinary skill in the art is to be understood that; can modify to the technical solution of the utility model or equivalent replacement, and not depart from essence and the scope of technical solutions of the utility model.

Claims (8)

1. a leakage current detection protection circuit, it is characterized in that: comprise current-voltage conversion processing circuit, comparison circuit, switching tube and external indicating circuit, described current-voltage conversion processing circuit gathers the leakage current of wire pair ground wire to be measured, this leakage current is converted to voltage signal A by described current-voltage conversion processing circuit, this voltage signal A is inputed to an input of comparison circuit, another input of comparison circuit is reference voltage signal B, when A is greater than B, comparison circuit exports a kind of signal makes switching tube conducting to drive external indicating circuit work, when A is less than B, comparison circuit exports another signal makes switching tube cut-off that external indicating circuit is not worked.
2. a kind of leakage current detection protection circuit as claimed in claim 1, it is characterized in that: described current-voltage conversion processing circuit comprises Current Transmit 1, resistance RM, diode D1 and electric capacity C1, described comparison circuit is comparator U1, described switching tube comprises resistance R3 and triode Q1, described external indicating circuit comprises LED 1, two inputs connecting to neutral line N and ground wire PE respectively of described Current Transmit 1, one end of an output connecting resistance RM of described Current Transmit 1 and the positive pole of diode D1, the negative pole of described diode D1 connects the positive pole of described electric capacity C1 and the positive input terminal (11) of comparator U1, the negative pole of described electric capacity C1 connects the other end of described resistance RM, another output of described Current Transmit 1 and ground GND, the negative input end (10) of described comparator U1 meets power supply VCC, the power end (3) of described comparator U1 connects one end of power supply VCC and resistance R3, the output (13) of another termination comparator U1 of described resistance R3, the collector electrode of triode Q1 and the base stage of triode Q1, the emitter of described triode Q1 connects the positive pole of described LED 1, the minus earth GND of described LED 1.
3. a kind of leakage current detection protection circuit as claimed in claim 2, is characterized in that: be connected to buzzer BZ1 between the negative pole of described LED 1 and ground GND.
4. a kind of leakage current detection protection circuit as claimed in claim 2, is characterized in that: the turn ratio of described current transformer is 10:1, and the value of described resistance RM is 82.5 Ω.
5. a kind of leakage current detection protection circuit as claimed in claim 2, is characterized in that: described resistance RM comprises resistance R1 and R2 of series connection.
6. a kind of leakage current detection protection circuit as claimed in claim 2, is characterized in that: the model of described comparator is LM339NG.
7. a kind of leakage current detection protection circuit as claimed in claim 2, is characterized in that: the model of described triode is MMBT2222A.
8. a kind of leakage current detection protection circuit as claimed in claim 1, is characterized in that: described external indicating circuit is digital signal processing chip DSP.
CN201520063312.7U 2015-01-29 2015-01-29 A kind of leakage current detection protection circuit Active CN204391679U (en)

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Application Number Priority Date Filing Date Title
CN201520063312.7U CN204391679U (en) 2015-01-29 2015-01-29 A kind of leakage current detection protection circuit

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105093053A (en) * 2015-06-26 2015-11-25 天长市富安电子有限公司 Current abnormity detection circuit
CN107749285A (en) * 2017-11-14 2018-03-02 深圳市华星光电技术有限公司 One kind electric leakage flow control circuit and control method
TWI627421B (en) * 2017-08-22 2018-06-21 華邦電子股份有限公司 Leakage current detection apparatus and detection method thereof
CN109425802A (en) * 2017-08-22 2019-03-05 华邦电子股份有限公司 Leak current detection device and its detection method
CN111030048A (en) * 2019-11-21 2020-04-17 宇龙计算机通信科技(深圳)有限公司 Electric leakage protection circuit, charging wire and charger

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105093053A (en) * 2015-06-26 2015-11-25 天长市富安电子有限公司 Current abnormity detection circuit
TWI627421B (en) * 2017-08-22 2018-06-21 華邦電子股份有限公司 Leakage current detection apparatus and detection method thereof
CN109425802A (en) * 2017-08-22 2019-03-05 华邦电子股份有限公司 Leak current detection device and its detection method
CN107749285A (en) * 2017-11-14 2018-03-02 深圳市华星光电技术有限公司 One kind electric leakage flow control circuit and control method
CN111030048A (en) * 2019-11-21 2020-04-17 宇龙计算机通信科技(深圳)有限公司 Electric leakage protection circuit, charging wire and charger
CN111030048B (en) * 2019-11-21 2021-10-22 宇龙计算机通信科技(深圳)有限公司 Electric leakage protection circuit, charging wire and charger

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