CN208508521U - A kind of protection circuit for resisting surge voltage impact and anti-over-voltage and over-current - Google Patents
A kind of protection circuit for resisting surge voltage impact and anti-over-voltage and over-current Download PDFInfo
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- CN208508521U CN208508521U CN201821190437.6U CN201821190437U CN208508521U CN 208508521 U CN208508521 U CN 208508521U CN 201821190437 U CN201821190437 U CN 201821190437U CN 208508521 U CN208508521 U CN 208508521U
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Abstract
A kind of protection circuit for resisting surge voltage impact and anti-over-voltage and over-current is related to a kind of circuit protected under output overvoltage, overcurrent condition to normal work circuit.The protection circuit not only realizes that antisurge surge protection also has overvoltage protection, overcurrent protection function, which improves the adaptation function of protection circuit, and then improves the flexibility and utilization efficiency of protection circuit.
Description
Technical field
The circuit that the utility model relates to a kind of to protect normal work circuit under output overvoltage, overcurrent condition,
In particular to a kind of protection circuit for resisting surge voltage impact and anti-over-voltage and over-current.
Background technique
As the complexity and integrated level of electronic system are higher and higher, and the operating voltage of chip and Acquisition Circuit is increasingly
Low, electronic system is also higher and higher to reliability, stability and the requirement of safety.Especially when acquiring signal in Acquisition Circuit
When for high-voltage large current, very big surge voltage often is generated in the moment for connecting acquisition signal.Master control in Acquisition Circuit
Chip, which can reset, restarts, and causes acquisition information incorrect, causes control signal abnormal.This result is abnormally dangerous so protection
The design importance of circuit is also increasingly stronger.In the design protection of circuit, whether the design application of circuit protection is reasonable, will be straight
Connect the protecting effect for influencing electronic system circuitry protection scheme.In recent years in the market, either electronic product, automotive electronics, also
It is the various equipment of military domain, industrial circle, civil field, it is all higher and higher to miniaturization, integrated requirement.Therefore right
The size of the base electronics components such as capacitor, inductor, resistor and circuit protection component requires also increasingly harsher.
In this intellectualization times, protecting circuit designed will also be related to intelligence.Such as: local circuit protection and whole electricity
The feedback of road protection.When a certain circuit protecting element acts, reported immediately to control platform, and to the guarantor of integrated circuit
Protection element issues protection act instruction, realizes total tune defencive function；There are also actives to protect, that is, protecting no longer is only to limit to
In secure context, but rise to make circuit original function it is unaffected and improve product reliability angle on.Therefore main
Dynamic element, chip can be gradually introducing circuit protection field.
Summary of the invention
In view of the deficienciess of the prior art, the purpose of the utility model is to provide a kind of resistance surge voltage impact and preventing
It is also higher and higher to reliability, stability and the requirement of safety to solve electronic system for the protection circuit of over-voltage and over-current.
The technical scheme adopted by the utility model is a kind of protection electricity for resisting surge voltage impact and anti-over-voltage and over-current
Road, including power circuit, are characterized in that, further includes: for acquiring the sample circuit of load end current signal, for that will adopt
The current signal collected switchs to the governor circuit of voltage signal, for the voltage signal and electricity based on the received from governor circuit
Comparison circuit that the voltage signal of source circuit output is compared, three for being connected according to the result pair of comparison circuit and load
Protection circuit that the on-off of pole pipe is controlled, for when protecting circuit work feedback load terminal voltage signal give protection circuit
Feed circuit；The power circuit is connect with governor circuit, feed circuit and comparison circuit respectively, the sampling of sample circuit
End is connected with load, and the output end of sample circuit is connect with the input terminal of the input terminal of governor circuit and feed circuit respectively, main
The input terminal of the output end and comparison circuit of controlling circuit connects, and the output end of comparison circuit is connected with the input terminal of protection circuit,
The output end of feed circuit is connect with the input terminal of governor circuit and protection circuit respectively.
In above scheme, the governor circuit includes current detecting chip, and the input pin of current detecting chip is through
The connection of the output end of 15 resistance and sample circuit, the output pin of current detecting chip through first resistor and comparison circuit the
The inverting input terminal of one comparator connects.
In above scheme, the comparison circuit includes first comparator and the second comparator, the reverse phase of first comparator
Input terminal connects the output end of governor circuit, and the normal phase input end of first comparator connects 2.5V power supply, first comparator it is defeated
Outlet is connect with the cathode of the second diode of protection circuit；
The inverting input terminal of second comparator connects the load terminal voltage after dividing and detects signal, and the second comparator is just
Phase input terminal connects 2.5V power supply, one end of the 14th resistance of the output end connection protection circuit of the second comparator.
In above scheme, the feed circuit includes the 9th resistance, the tenth resistance and third comparator, the 9th resistance
One end connects 2.5V power supply, and the other end of the 9th resistance is connect with the inverting input terminal of one end of the tenth resistance, third comparator,
The other end of tenth resistance is connect with the output end of third comparator, the normal phase input end and third capacitor one of third comparator
The collector connection at end, the first triode, third capacitor other end ground connection.
In above scheme, the protection circuit includes self-recovery fuse, the second triode, ceramic gas discharge tube
GDT and TVS diode；
The base stage of second triode connects the other end of the 14th resistance, and the collector connection of the second triode is negative
Carry end, the emitting stage ground connection of the second triode；
One TVS diode is sequentially connected in series ceramic gas discharge tube GDT and another TVS diode composition and successive load
The TVS protection branch being connected in parallel, two of them TVS diode, ceramic gas discharge tube GDT be also connected to ground respectively, the
Self-recovery fuse is additionally provided in one TVS diode and the connection line of input terminal.
The beneficial effects of the utility model are: the protection circuit of the resistance surge voltage impact and anti-over-voltage and over-current, not only
Realize that antisurge surge protection also has overvoltage protection, overcurrent protection function, which improves the adaptive of protection circuit
Function is answered, and then improves the flexibility and utilization efficiency of protection circuit.
Detailed description of the invention
In order to illustrate the embodiment of the utility model or the technical proposal in the existing technology more clearly, below will be to embodiment
Needed in attached drawing be briefly described, it should be apparent that, the accompanying drawings in the following description is only the utility model
Some embodiments for those of ordinary skill in the art without creative efforts, can also be according to these
Attached drawing obtains other attached drawings.
Fig. 1 is the protection circuit structure frame that surge voltage impact and anti-over-voltage and over-current are resisted in the utility model embodiment
Figure；
Fig. 2 is the circuit original that the protection circuit of surge voltage impact and anti-over-voltage and over-current is resisted in the utility model embodiment
Reason figure.
Specific embodiment
Keep the above objects, features, and advantages of the utility model more obvious and easy to understand, with reference to the accompanying drawing 1~Fig. 2
The utility model is described in further detail with specific embodiment.
The protection circuit of resistance surge voltage impact and anti-over-voltage and over-current that the present embodiment uses, comprising:
Power circuit 1 uses U1 and U2 two panels for providing voltage for governor circuit and feed circuit
TL431TL431PK is realized.Wherein U1 provides 10V power supply to entire circuit, and U1 is used as the voltage benchmark source of 2.5V.This reality
Applying DC input circuit input voltage in example is 27V ± 3V, is powered after filtering to power circuit.
Sample circuit 2, for acquiring the current signal of load end.
Governor circuit 3, for collected current signal to be switched to voltage signal, the present embodiment uses current detecting chip
MAX4080SASA is as governor circuit.High-precision current detection chip direct voltage output signal, it is possible to provide up to put for 60 times
Big multiple.
Comparison circuit 4, the voltage for voltage signal and power circuit output based on the received from governor circuit are believed
It number is compared, the output end that comparator is controlled if reverse inter-input-ing voltage is higher than positive input voltage exports low level.This reality
The comparison circuit for applying example includes operation comparator U4A and U4C, and model is LM339.
Feed circuit 5 is used for the feedback load terminal voltage signal when protecting circuit work and gives protection circuit；
Circuit 6 is protected, for controlling according to the result pair of comparison circuit and the on-off of the triode of load connection.
Power circuit 1 is connect with governor circuit 3, feed circuit 5 and comparison circuit 4 respectively, the sampling end of sample circuit 2 with
Load connection, the output end of sample circuit 2 are connect with the input terminal of the input terminal of governor circuit 3 and feed circuit 5 respectively, master control
The output end of circuit 3 is connect with the input terminal of comparison circuit 4, and the output end of comparison circuit 4 and the input terminal of protection circuit 6 connect
It connects, the output end of feed circuit 5 is connect with the input terminal of governor circuit 3 and protection circuit 6 respectively.
The protection circuit of resistance surge voltage impact and anti-over-voltage and over-current in the present embodiment, particular circuit configurations are as follows:
The sampling end VOUT connection of load end and sample circuit, for acquiring the current signal of load end.Sampling end VOUT
Connect one end of resistance R15, one end connection of the RS- pin, resistance R5 of the other end and MAX4080SASA of resistance R15, resistance
The other end of R5 is connect with RS+ pin.Anti-phase input of the OUT output pin of MAX4080SASA through resistance R1 Yu comparator U4A
4 connection of end.The normal phase input end 5 of comparator U4A connects 2.5V power supply, the output end 2 of comparator U4A and two poles of protection circuit
The cathode of pipe D2 connects, and the anode of diode D2 is connect through resistance R14 with the base stage of triode V2.The output end of comparator U4A
It is connect through resistance R6 with the emitting stage of triode V1, the positive of the comparator U4D of the collector and feed circuit of triode V1 is defeated
Enter the anode connection at end 10, diode D1, the inverting input terminal 11 of comparator U4D connects the one end resistance R9 and the electricity of feed circuit
The one end R10 is hindered, wherein the other end of resistance R9 connects 2.5V power supply, the other end of resistance R10 and the output end of comparator U4D
13, one end connection of resistance R11, the other end of resistance R11 are connect with the cathode of the cathode of diode D1, diode D3, two poles
Base stage of the anode of pipe D3 through triode V2 in resistance R14 connection protection circuit.
The inverting input terminal 8 of comparator U4C connects the load terminal voltage after dividing and detects signal, and comparator U4C is just
Phase input terminal 9 connects 2.5V power supply, one end of the resistance R14 of the output end connection protection circuit of comparator U4C.
The protection circuit of the present embodiment includes self-recovery fuse F9, triode V2, and the base stage of triode V2 connects resistance
The other end of R14, the collector of triode V2 connect load, the emitting stage ground connection of triode V2.The protective loop is used for over-voltage
Protection and overcurrent protection.
First TVS diode is sequentially connected ceramic gas discharge tube GDT and the second TVS diode composition and successive load simultaneously
Join the road of the TVS protection of connection, also with casing the end GND1 connects respectively by two of them TVS diode, ceramic gas discharge tube GDT
It connects.
Self-recovery fuse F9 is additionally provided between first TVS diode and input terminal VIN.
Wherein, the course of work of current foldback circuit is as follows:
Once successive load end VOUT overcurrent will lead to comparator U4A overturning, export low level.On the one hand pass through two poles
Pipe D2 drags down the base voltage of triode V2, and protection output signal VOUT value can then be got higher, and realizes overcurrent protection；Another party
Face can make triode V1 saturation conduction, and supply voltage VCC is applied directly on capacitor C3, and it is that supply voltage is straight that moment, which completes charging,
It connects on the pin 10 for being added to comparator U4D, and the voltage of the pin 11 of comparator U4D is 6.2V or so, once the electricity of pin 10
Pressure is higher than the voltage of pin 11, forces comparator U4D overturning output low level, is dragged down V2 base voltage by diode D3,
Realize protection.The effect of resistance R8 is to prevent triode V1 from having faint leakage current to fill to capacitor C3 when turning off in the present embodiment
Electricity.
After overcurrent occur and being protected, short circuit current disappears immediately, and U4A restores output high level, and C3 stops charging；Cause
It will not be mutated for the voltage of C3, so comparator U4D still exports low level, sustainable protection, while capacitor C3 passes through diode
D1 and resistance R11 start to discharge, and the voltage on the pin 11 of comparator U4D is 1.25V or so at this time；When capacitor C3 be discharged to it is low
It is that U4D overturning output high level, output restores normal in 1.25V.If excessive current loads portion is removed, concussion will form, after dismounting
It can restore to work normally automatically.
The course of work of voltage protection circuit is as follows in the present embodiment:
Voltage detection signal passes through in the input comparator U4C of the end ISN after being divided by non-essential resistance, using LM339(U4) make
For core comparator, when comparator U4C overturns output low level, control VOUT exports high level, realizes overvoltage protection.
TVS protects the working principle of circuit as follows in the present embodiment:
After instantaneous voltage is more than circuit normal working voltage, avalanche breakdown will occur for TVS diode, to be supplied to wink
When one super-low impedance of electric current access, as a result, transient current is shorted to GND by TVS.To avoid by protective loop
It is always maintained at blanking voltage.And after transient pulse terminates, TVS diode is restored automatically again to high-impedance state, entire circuit
It is returned to normal voltage state.
Above description is only a specific implementation of the present invention, but the protection scope of the utility model is not limited to
In this, anyone skilled in the art within the technical scope disclosed by the utility model, can readily occur in variation
Or replacement, it should be covered within the scope of the utility model.Therefore, the protection scope of the utility model should be with the power
Subject to the protection scope that benefit requires.
Claims (5)
1. a kind of protection circuit for resisting surge voltage impact and anti-over-voltage and over-current, including power circuit, which is characterized in that also wrap
It includes: the sample circuit for acquiring load end current signal, the master control for collected current signal to be switched to voltage signal
Circuit, the ratio being compared for the voltage signal based on the received from governor circuit with the voltage signal that power circuit exports
Compared with circuit, the protection circuit for being controlled according to the result pair of comparison circuit and the on-off of the triode of load connection, use
In protect circuit work when feedback load terminal voltage signal to protection circuit feed circuit；The power circuit respectively with
Governor circuit, feed circuit are connected with comparison circuit, and the sampling end of sample circuit and load connect, the output end point of sample circuit
It is not connect with the input terminal of the input terminal of governor circuit and feed circuit, the output end of governor circuit and the input terminal of comparison circuit
Connection, the output end of comparison circuit and protects the input terminal of circuit to connect, the output end of feed circuit respectively with governor circuit and
Protect the input terminal connection of circuit.
2. resisting the protection circuit of surge voltage impact and anti-over-voltage and over-current as described in claim 1, which is characterized in that described
Governor circuit include current detecting chip, the input pin of current detecting chip is through the output of the 15th resistance and sample circuit
The output pin of end connection, current detecting chip connects through the inverting input terminal of the first comparator of first resistor and comparison circuit
It connects.
3. resisting the protection circuit of surge voltage impact and anti-over-voltage and over-current as described in claim 1, which is characterized in that described
Comparison circuit include first comparator and the second comparator, the output of the inverting input terminal connection governor circuit of first comparator
End, the normal phase input end of first comparator connect 2.5V power supply, the output end of first comparator and the two or two pole of protection circuit
The cathode of pipe connects；
The inverting input terminal of second comparator connects the load terminal voltage after dividing and detects signal, and the positive of the second comparator is defeated
Enter end connection 2.5V power supply, one end of the 14th resistance of the output end connection protection circuit of the second comparator.
4. resisting the protection circuit of surge voltage impact and anti-over-voltage and over-current as described in claim 1, which is characterized in that described
Feed circuit include the 9th resistance, the tenth resistance and third comparator, one end of the 9th resistance connects 2.5V power supply, the 9th electricity
The other end of resistance is connect with the inverting input terminal of one end of the tenth resistance, third comparator, the other end and third of the tenth resistance
The output end of comparator connects, and the collector of the normal phase input end of third comparator and third capacitor one end, the first triode connects
It connects, third capacitor other end ground connection.
5. resisting the protection circuit of surge voltage impact and anti-over-voltage and over-current as described in claim 1, which is characterized in that described
Protection circuit include the second triode, self-recovery fuse, ceramic gas discharge tube GDT and TVS diode；
The base stage of second triode connects the other end of the 14th resistance, and the collector of the second triode connects load
End, the emitting stage ground connection of the second triode；
First TVS diode is sequentially connected in series ceramic gas discharge tube GDT and the second TVS diode composition company in parallel with successive load
The TVS protection branch connect, two of them TVS diode, ceramic gas discharge tube GDT are also connected to ground respectively, in the first TVS bis-
Self-recovery fuse is additionally provided in pole pipe and the connection line of input terminal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821190437.6U CN208508521U (en) | 2018-07-26 | 2018-07-26 | A kind of protection circuit for resisting surge voltage impact and anti-over-voltage and over-current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821190437.6U CN208508521U (en) | 2018-07-26 | 2018-07-26 | A kind of protection circuit for resisting surge voltage impact and anti-over-voltage and over-current |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208508521U true CN208508521U (en) | 2019-02-15 |
Family
ID=65290935
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201821190437.6U Active CN208508521U (en) | 2018-07-26 | 2018-07-26 | A kind of protection circuit for resisting surge voltage impact and anti-over-voltage and over-current |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208508521U (en) |
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2018
- 2018-07-26 CN CN201821190437.6U patent/CN208508521U/en active Active
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