CN206894221U - A kind of leakage protection circuit - Google Patents

Abstract

It the utility model is related to electronic circuit field.The utility model discloses a kind of leakage protection circuit,Including zero sequence current mutual inductor ZCT,Earth leakage protective chip IC,Electrical apparatus release and electrical apparatus release drive circuit,The model 2140 of the earth leakage protective chip IC,The zero sequence current mutual inductor ZCT is arranged on live wire and zero line,The Vref ends of one termination earth leakage protective chip IC of the secondary coil of the zero sequence current mutual inductor ZCT,The other end connects the VFB ends of earth leakage protective chip IC by electric capacity C4,The both ends of the secondary coil of the zero sequence current mutual inductor ZCT are parallel with resistance R5 and electric capacity C5,The Rset ends of the earth leakage protective chip IC connect the Ground ends of earth leakage protective chip IC by the resistance R4 and electric capacity C6 of parallel connection,The control signal of the SCR Trigger termination electrical apparatus release drive circuits of the earth leakage protective chip IC,The electrical apparatus release drive circuit is used for the break-make for controlling electrical apparatus release,The electrical apparatus release is serially connected on live wire,Or the electrical apparatus release is serially connected on live wire and zero line respectively.

Description

A kind of leakage protection circuit

Technical field

The utility model belongs to electronic circuit field, electric leakage good more particularly to a kind of Electro Magnetic Compatibility, simple in construction Protection circuit.

Background technology

With the development and growth in the living standard of technology, the electrical equipment of various functions is more and more, and the life of people is almost Various electrical equipment are be unable to do without, and it is increasingly widespread with electrical equipment, and people and the chance of electrical contact are more and more, in order that user obtains Preferably protect, be designed with leakage protection circuit on the current supply circuit of many electrical equipment now, when electric equipment leaks electricity, or people When body electric shock or apparatus insulated damage, leakage protection circuit can automatically cut off power supply within a few tens of milliseconds, make user from touching The harm of electricity, protect the life security and property safety of user.

But existing various leakage protection circuits are also present in many shortcomings：1. circuit structure is complicated, cost is high, stability Difference, reliability are low；2. Electro Magnetic Compatibility is poor, being less than in 150KHz frequency ranges in standard GB/T 18499 can not be passed through Common mode conduction interference is tested.In order to improve Electro Magnetic Compatibility, many effort have all been done by many producers, but effect is undesirable, open Patent：Although CN203135399U by increasing electric capacity C5, makes it can be by required " less than 150KHz frequencies in national standard Common mode conduction interference experiment in the range of rate ", but electric capacity C5 will be made bigger, and electric capacity C5 can influence it very much greatly Its EMC experiments, and it is more and more stricter now for the test request and the market demand of Electro Magnetic Compatibility, and this just forces producer to need Further improve Electro Magnetic Compatibility.

The content of the invention

The purpose of this utility model is to provide that a kind of circuit structure is simple, and cost is low to solve the above problems, performance It is stable, and the leakage protection circuit that Electro Magnetic Compatibility is good.

Therefore, the utility model discloses a kind of leakage protection circuit, including zero sequence current mutual inductor ZCT, earth leakage protective Chip IC, electrical apparatus release and electrical apparatus release drive circuit, the model 2140 of the earth leakage protective chip IC, the zero sequence current mutual inductance Device ZCT is arranged on live wire and zero line, a termination earth leakage protective chip IC of the secondary coil of the zero sequence current mutual inductor ZCT Vref ends, the other end connects the VFB ends of earth leakage protective chip IC by electric capacity C4, and the zero sequence current mutual inductor ZCT's is secondary The both ends of coil are parallel with resistance R5 and electric capacity C5, and the Rset ends of the earth leakage protective chip IC pass through resistance R4 and electricity in parallel Hold the Ground ends that C6 connects earth leakage protective chip IC, the SCR Trigger termination electrical apparatus release drivings of the earth leakage protective chip IC The control signal of circuit, the electrical apparatus release drive circuit are used for the break-make for controlling electrical apparatus release, and the electrical apparatus release is serially connected in live wire On, or the electrical apparatus release is serially connected on live wire and zero line respectively.

Further, the model FM2140 of the earth leakage protective chip IC.

Further, the electrical apparatus release is the electrical apparatus release of double-contact, and the double-contact is serially connected on live wire and zero line respectively.

Further, the electrical apparatus release drive circuit includes the coil of controllable silicon SCR, the controllable silicon SCR and electrical apparatus release Series connection is followed by between live wire and zero line, and the control pole of the controllable silicon SCR meets the SCR Trigger of earth leakage protective chip IC End.

Further, the control pole of the controllable silicon SCR also serial capacitance C1 connecting to neutral line.

Further, it is further connected with piezo-resistance MOV between the live wire and zero line.

Further, in addition to indicator light circuit, the indicator light circuit include diode D1, resistance R2 and light-emitting diodes Pipe D2, the diode D1, resistance R2 and light emitting diode D2, which are sequentially connected in series, to be followed by between live wire and zero line.

Further, the zero sequence current mutual inductor ZCT is set on live wire and zero line, zero sequence current mutual inductor ZCT's One end of primary winding is started to exchange fire line, and the other end is sequentially connected in series button AJ and resistance R1 connecting to neutral lines.

Advantageous effects of the present utility model：

The utility model has a creepage protection function, and circuit structure is simple, it is easy to accomplish, cost is low, stable performance, reliably Property it is high, and by increasing electric capacity C5 and C6, make the Electro Magnetic Compatibility of circuit more preferable, more easily just by required by national standard " less than the common mode conduction interference experiment in 150KHz frequency ranges ", and do not influence other EMC experiments of circuit.

Brief description of the drawings

Fig. 1 is the circuit theory diagrams of the utility model specific embodiment.

Embodiment

The utility model is further illustrated in conjunction with the drawings and specific embodiments.

As shown in figure 1, a kind of leakage protection circuit, including zero sequence current mutual inductor ZCT, earth leakage protective chip IC, dropout Device and electrical apparatus release drive circuit, the model 2140 of the earth leakage protective chip IC, in this specific embodiment, earth leakage protective chip IC model FM2140 (low-power consumption double ground fault arc extinguishing chip, Low Power Two-Wire Ground Fault Interrupter), certainly, in other embodiments, earth leakage protective chip IC can also be itself function and construction on The identical or equivalent other models of FM2140 or the earth leakage protective chip IC specially made, this is that those skilled in the art can be light Easily realize, no longer describe in detail.

The zero sequence current mutual inductor ZCT is arranged on live wire L and zero line N, in this specific embodiment, live wire L and zero line N One termination AC power, another terminating load.The zero sequence current mutual inductor ZCT is set on live wire L and zero line N, zero sequence Start to exchange fire line L for one end of current transformer ZCT primary winding, and the other end is sequentially connected in series button AJ and resistance R1 connecting to neutral lines N.

The Vref ends of one termination earth leakage protective chip IC of the secondary coil of the zero sequence current mutual inductor ZCT, the other end The VFB ends of earth leakage protective chip IC are connect by electric capacity C4, the both ends of the secondary coil of the zero sequence current mutual inductor ZCT are parallel with Resistance R5 and electric capacity C5, the Rset ends of the earth leakage protective chip IC connect earth leakage protective core by the resistance R4 and electric capacity C6 of parallel connection Piece IC Ground ends, the control signal of the SCR Trigger termination electrical apparatus release drive circuits of the earth leakage protective chip IC, The electrical apparatus release drive circuit is used for the break-make for controlling electrical apparatus release, and the electrical apparatus release is serially connected on live wire L, or the electrical apparatus release point It is not serially connected on live wire L and zero line N.

In this specific embodiment, electric capacity C3 is connected between the Ground ends and Vref ends of earth leakage protective chip IC, electric leakage is protected Protect the Ground ends of chip IC and be connected to electric capacity C2 between C Delay ends.

In this specific embodiment, the electrical apparatus release is the electrical apparatus release of double-contact, and the double-contact K1 and K2 is serially connected in respectively On live wire L and zero line N.

In this specific embodiment, the electrical apparatus release drive circuit includes controllable silicon SCR, the controllable silicon SCR and electrical apparatus release Coil TK series connection be followed by between live wire L and zero line N, the control pole of the controllable silicon SCR meets the SCR of earth leakage protective chip IC Trigger ends.Certainly, in other embodiments, electrical apparatus release drive circuit can also use existing circuit, such as use metal-oxide-semiconductor Or triode realizes that this is that those skilled in the art can realize easily, no longer describe in detail.

In this specific embodiment, electric capacity C5 and C6 capacitance size can be selected according to actual conditions, and this is ability What field technique personnel can realize easily, no longer describe in detail.

In this specific embodiment, the control pole also serial capacitance C1 connecting to neutral line N of the controllable silicon SCR, it is filtered, improves Stability and reliability.

In this specific embodiment, piezo-resistance MOV is further connected between the live wire L and zero line N, is protected.

In this specific embodiment, in addition to indicator light circuit, the indicator light circuit include diode D1, resistance R2 and hair Optical diode D2, the diode D1, resistance R2 and light emitting diode D2, which are sequentially connected in series, to be followed by between live wire L and zero line N.

Operation principle：Leaked electricity when loading, or when person electric shock or apparatus insulated damage, pass through zero sequence current mutual inductor For the current phasor of ZCT primary windings with when being not zero, zero sequence current mutual inductor ZCT secondary coils produce induced voltage, through electric leakage Protection chip IC is amplified, compares and handled, when residual current, which reaches, adjusts action current value, from earth leakage protective chip IC SCR Trigger ends export reliable and stable signal and turn on controllable silicon SCR, electrical apparatus release action, double-contact K1 and K2 disconnect, cut Power-off source, plays electric leakage and electrical shock protection effect, and circuit structure is simple, it is easy to accomplish, cost is low, stable performance, and reliability is high.

Electric capacity C5 and C6 effect are to make the Electro Magnetic Compatibility of the leakage protection circuit more preferable in circuit, are more just passed through easily In standard GB/T 18499 required " less than the common mode conduction interference experiment in 150KHz frequency ranges ", and do not influence electricity Other EMC experiments on road.

Although specifically showing and describing the utility model with reference to preferred embodiment, those skilled in the art should This is understood, is not departing from the spirit and scope of the present utility model that appended claims are limited, in form and details On the utility model can be made a variety of changes, be the scope of protection of the utility model.

Claims (8)

1. A kind of 1. leakage protection circuit, it is characterised in that：Including zero sequence current mutual inductor ZCT, earth leakage protective chip IC, electrical apparatus release With electrical apparatus release drive circuit, the model 2140 of the earth leakage protective chip IC, the zero sequence current mutual inductor ZCT is arranged on fire On line and zero line, the Vref ends of a termination earth leakage protective chip IC of the secondary coil of the zero sequence current mutual inductor ZCT are another End connects the VFB ends of earth leakage protective chip IC by electric capacity C4, and the both ends of the secondary coil of the zero sequence current mutual inductor ZCT are in parallel There are resistance R5 and electric capacity C5, the Rset ends of the earth leakage protective chip IC connect earth leakage protective by the resistance R4 and electric capacity C6 of parallel connection The Ground ends of chip IC, the control input of the SCR Trigger termination electrical apparatus release drive circuits of the earth leakage protective chip IC End, the electrical apparatus release drive circuit are used for the break-make for controlling electrical apparatus release, and the electrical apparatus release is serially connected on live wire, or the electrical apparatus release It is serially connected in respectively on live wire and zero line.
2. 2. leakage protection circuit according to claim 1, it is characterised in that：The model of the earth leakage protective chip IC FM2140。
3. 3. leakage protection circuit according to claim 1, it is characterised in that：The electrical apparatus release is the electrical apparatus release of double-contact, The double-contact is serially connected on live wire and zero line respectively.
4. 4. the leakage protection circuit according to claim 1 or 3, it is characterised in that：The electrical apparatus release drive circuit includes can Silicon SCR is controlled, the controllable silicon SCR is connected with the coil of electrical apparatus release and is followed by between live wire and zero line, the control of the controllable silicon SCR Pole processed connects the SCR Trigger ends of earth leakage protective chip IC.
5. 5. leakage protection circuit according to claim 4, it is characterised in that：The control pole of the controllable silicon SCR also concatenates Electric capacity C1 connecting to neutral lines.
6. 6. leakage protection circuit according to claim 1, it is characterised in that：It is further connected between the live wire and zero line pressure-sensitive Resistance MOV.
7. 7. leakage protection circuit according to claim 1, it is characterised in that：Also include indicator light circuit, the indicator lamp Circuit includes diode D1, resistance R2 and light emitting diode D2, and the diode D1, resistance R2 and light emitting diode D2 go here and there successively Connection is followed by between live wire and zero line.
8. 8. leakage protection circuit according to claim 1, it is characterised in that：The zero sequence current mutual inductor ZCT is set in On live wire and zero line, one end of zero sequence current mutual inductor ZCT primary winding is started to exchange fire line, and the other end is sequentially connected in series button AJ and electricity Hinder R1 connecting to neutral lines.