CN103633616B - A kind of current foldback circuit - Google Patents
A kind of current foldback circuit Download PDFInfo
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- CN103633616B CN103633616B CN201310606159.3A CN201310606159A CN103633616B CN 103633616 B CN103633616 B CN 103633616B CN 201310606159 A CN201310606159 A CN 201310606159A CN 103633616 B CN103633616 B CN 103633616B
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- clutter
- deadlock
- current foldback
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Abstract
The invention discloses a kind of current foldback circuit; including sampling end, protection control signal output, anti-clutter circuit, output circuit and deadlock circuit; the input of anti-clutter circuit is described sampling end; the input of the output termination output circuit of anti-clutter circuit, the output of output circuit is described protection control signal output；The output controlling termination output circuit of deadlock circuit, the control end of the output termination output circuit of deadlock circuit；When the voltage of sampling end exceedes setting value, anti-clutter circuit first carries out energy storage, when the energy that anti-clutter circuit stores reaches setting value, and output signal trigger output circuit output protection control signal；The protection control signal of output circuit output triggers deadlock circuit, and output signal is locked in the output state of protection control signal by deadlock circuit.The anti-clutter circuit of the present invention filters out abnormal high voltage pulse by energy storage, prevents circuit erroneous action, improves the antijamming capability of current foldback circuit.
Description
[technical field]
The present invention relates to the protection circuit of power supply, particularly relate to a kind of current foldback circuit.
[background technology]
Current a part of Switching Power Supply uses the form of interval break-make to realize stream after output short-circuit or overload
Protection；Which be by use the resistance (such as the R19 of Fig. 1) that is connected in accessory power supply winding of regulation or
The resistance (such as the R18 of Fig. 1) of regulation sampling resistor realizes, thus reaches to control switching tube and open and turn off
Control to export electric current.Another kind of situation is to be built-in with defencive function by main control chip to realize overcurrent protection.
The first protected mode by the input voltage of power supply, load, the factor impact such as transformer characteristic,
Very debugging difficulty acquires the parameter of a satisfaction, when device parameters is unreasonable, and long-time interval break-make, also can
Cause device seriously to generate heat, semiconductor devices may be damaged；The second protected mode is protected by built-in chip type
Function, guard time is fixed, and is difficult to adjust, poor anti jamming capability.
[summary of the invention]
The technical problem to be solved in the present invention is to provide the current foldback circuit that a kind of antijamming capability is strong.
The present invention to solve the technical problem that being to provide a kind of stream of crossing being conveniently adjusted trigger current value protects further
Protection circuit.
In order to solve above-mentioned technical problem, the technical solution used in the present invention is, a kind of current foldback circuit,
Anti-clutter circuit, output circuit and the deadlock triggered including sampling end, protection control signal output, energy storage
Circuit, the input of anti-clutter circuit is described sampling end, the output termination output circuit of anti-clutter circuit
Input, the output of output circuit is described protection control signal output；The control of deadlock circuit
The output of termination output circuit, the control end of the output termination output circuit of deadlock circuit；When sampling end
When voltage exceedes setting value, anti-clutter circuit first carries out energy storage, and the energy that anti-clutter circuit stores reaches to set
During value, output signal trigger output circuit output protection control signal；The protection of output circuit output controls letter
Number trigger deadlock circuit, deadlock circuit output signal is locked in protection control signal output state.
Above-described current foldback circuit, anti-clutter circuit includes a NPN triode, a PNP tri-
Pole pipe, storage capacitor, discharge resistance and Zener diode, the colelctor electrode of a NPN triode passes through the 3rd
Resistance connects power supply, grounded emitter, and base stage is the input of anti-clutter circuit；Sending out of first PNP triode
Emitter-base bandgap grading connects power supply, colelctor electrode connects the first end of storage capacitor, and base stage connects the colelctor electrode of a NPN triode；
Second end ground connection of storage capacitor, discharge resistance is in parallel with storage capacitor；The negative electrode of Zener diode connects energy storage
First end of electric capacity, the anode of Zener diode is the output of anti-clutter circuit.
Above-described current foldback circuit, anti-clutter circuit includes the first resistance and the second resistant series composition
Bleeder circuit, the first end ground connection of bleeder circuit, the second end is the sampling end of current foldback circuit, first
The tie point of resistance and the second resistance connects the base stage of a NPN triode.
Above-described current foldback circuit, anti-clutter circuit includes current-limiting resistance, the first PNP triode
Emitter stage connects power supply by current-limiting resistance.
Above-described current foldback circuit, output circuit includes the 2nd NPN triode, the 2nd NPN tri-pole
The colelctor electrode of pipe connects power supply by the 4th resistance, grounded emitter, and base stage connects the output of anti-clutter circuit；
The colelctor electrode of the 2nd NPN triode is the protection control signal output of current foldback circuit.
Above-described current foldback circuit, deadlock circuit includes the second PNP triode, the 2nd PNP tri-pole
The emitter stage of pipe connects power supply, and colelctor electrode connects the control end of the output termination output circuit as deadlock circuit, base
Pole as control termination output circuit output.
Above-described current foldback circuit, including main circuit, main circuit include control chip, switching tube and
Sampling resistor, switching tube passes through sampling resistor ground connection, the control signal output termination switching tube of control chip
Control end；The tie point of switching tube and sampling resistor connects the input of anti-clutter circuit as sampled signal output
End, the output of output circuit is as the protection signal input part of protection control signal output termination control chip；
During current foldback circuit output protection control signal, trigger main circuit control chip action, closing switch pipe
Output.
The anti-clutter circuit of current foldback circuit of the present invention filters out abnormal high voltage pulse by energy storage, anti-
Only circuit erroneous action, improves the antijamming capability of current foldback circuit.
[accompanying drawing explanation]
The present invention is further detailed explanation with detailed description of the invention below in conjunction with the accompanying drawings.
Fig. 1 is the circuit diagram of prior art current foldback circuit.
Fig. 2 is the circuit diagram of the embodiment of the present invention 1 current foldback circuit.
Fig. 3 is the embodiment of the present invention 2 current foldback circuit and the circuit diagram of main circuit combination.
[detailed description of the invention]
The structure of the embodiment of the present invention 1 current foldback circuit is as it is shown in figure 1, include that sampling end, protection control
Anti-clutter circuit, output circuit and the deadlock circuit that signal output part, energy storage trigger, anti-clutter circuit defeated
Entering end is described sampling end, the input of the output termination output circuit of anti-clutter circuit, output circuit
Output is described protection control signal output；The output controlling termination output circuit of deadlock circuit,
The control end of the output termination output circuit of deadlock circuit.
When the voltage of sampling end exceedes setting value, anti-clutter circuit first carries out energy storage, and anti-clutter circuit stores
Energy when reaching setting value, output signal trigger output circuit output protection control signal；Output circuit is defeated
The protection control signal gone out triggers deadlock circuit, and output signal is locked in protection control signal by deadlock circuit
Output state.Output circuit output protection control signal triggers main circuit control chip action, closes output.
Wherein, anti-clutter circuit includes NPN triode Q1, PNP triode Q2, storage capacitor C1, electric discharge
The colelctor electrode of resistance R7 and Zener diode D1, NPN triode Q1 connects the electricity of control chip by resistance R3
Source VCC, grounded emitter；The bleeder circuit that resistance R1 is composed in series with resistance R2, the first of bleeder circuit
End ground connection, the second end N1 is the sampling end of current foldback circuit as the input for anti-clutter circuit, resistance
The tie point of R1 and resistance R2 connects the base stage of NPN triode Q1.
The emitter stage of PNP triode Q2 meets the power supply VCC of control chip by current-limiting resistance R5, and colelctor electrode connects
First end of storage capacitor C1, base stage connects the colelctor electrode of NPN triode Q1 by resistance R4；Storage capacitor
The second end ground connection of C1, discharge resistance R7 is in parallel with storage capacitor C1；The negative electrode of Zener diode D1 connects storage
First end of energy electric capacity C1, the anode of Zener diode D1 is the output N3 of anti-clutter circuit.
Output circuit includes that the colelctor electrode of NPN triode Q4, NPN triode Q4 is connect by resistance R6 and R8
The power supply VCC of control chip, grounded emitter, base stage makees the defeated of the control termination anti-clutter circuit of output circuit
Go out to hold N3；The colelctor electrode of NPN triode Q4 is the output N4 of the protection control signal of current foldback circuit.
Deadlock circuit includes PNP triode Q3, and the emitter stage of PNP triode Q3 connects control by resistance R6
The power supply VCC of chip, colelctor electrode meets the control end of the output termination output circuit as deadlock circuit, i.e. NPN
The base stage of triode Q4, PNP triode Q3 base stage is as the output controlling termination output circuit of deadlock circuit
The colelctor electrode of end N4(NPN triode Q4).
After the voltage of the input N1 of anti-clutter circuit passes through bleeder circuit dividing potential drop, the base stage of NPN triode Q1
When voltage is more than 0.7V, i.e. Vn1*R2/(R1+R2) > 0.7V time, triode Q1 turns on, Q1 colelctor electrode
Level is pulled low, thus triode Q2 is also switched on, and storage capacitor C1 starts to charge up (charging by resistance R5
Time can be calculated by T=R5C1), when the voltage of first end of storage capacitor C1 exceedes voltage stabilizing two pole
Triode Q4 conducting during the threshold voltage of pipe D1, N4 point draws as low level, now triode Q3 conducting, guarantor
Holding N3 point is high level, further promotes Q4 conducting.So, the energy of once N1 end input reaches to set
During definite value, i.e. the base voltage of NPN triode Q1 when a period of time reaches setting value, current foldback circuit
Protection control signal output keep locked low level state, i.e. N4 point maintains low level state always,
Unless power down again, 2 terminal voltages of C1 are bled off and could recover original state.(if it is desired to be output as always
High level, can access a negative circuit at N4).
If N1 point has interference voltage to surpass overvoltage protection value in short-term, owing to having resistance R5 to electric capacity C1
Charging and the restriction of Zener diode D1, anti-clutter circuit will not export by mistake；Resistance R1 Yu R2 forms dividing potential drop
Circuit, can control the trigger voltage value of N1 point by the ratio regulating these 2 resistance values,；Triode
Q3 and Q4 forms locked circuit, can be locked when circuit abnormality, it is achieved block output, protects components and parts
It is not destroyed.
As in figure 2 it is shown, the circuit that the embodiment of the present invention 2 current foldback circuit and main circuit combine also includes control
Coremaking sheet U9, switching tube Q6 and sampling resistor R18, switching tube Q6 passes through sampling resistor R18 ground connection, control
The control signal output OUT of coremaking sheet U9 connects the control end of switching tube Q6 by resistance R15.Switching tube
The tie point of Q6 and sampling resistor R18 connects the input of anti-clutter circuit as sampled signal output and (crosses stream
The sampling end of protection circuit) N1, control chip U9 protection signal input part N5(Low level effective block
Pin COM) meet current foldback circuit protection control signal output N4 by diode D2
When main circuit switch pipe Q6 output short-circuit or overload, the electric current flowing through R18 sampling resistor can cross stream,
The i.e. voltage of the sampling end N1 point of current foldback circuit raises, through resistance R1, R2 dividing potential drop, NPN triode
When the base voltage of Q1 is more than 0.7V > 0.7V time, triode Q1 and Q2 turn on, storage capacitor C1 charge.
If the base voltage long period of NPN triode Q1 is more than 0.7V, the storage capacitor C1 long period is in
Charged state, when the voltage of storage capacitor C1 reaches Zener diode D1 conduction value, triode Q3, Q4
Entering locking state, the level of N5 point is pulled low always, and the output of switching tube Q6 is turned off, thus reaches
The purpose of current protection.
Owing to anti-clutter circuit has capacitor charging circuit, so when main circuit somewhat transships, will not misoperation,
Misleading if i.e. triode Q1 is of short duration, now electric capacity C1 charging, the voltage of electric capacity C1 slowly raises.As
When really the voltage of electric capacity C1 only rises to certain value (the most do not arrive Zener diode D1 opens threshold value),
Triode Q1 just turns off, and electric capacity C1 can be discharged by resistance R7, recovers reset condition；Current foldback circuit
The voltage of sampling end N1 point when having interference spike or short overload, this protection circuit will not misoperation, improve
The antijamming capability of current foldback circuit.
The current foldback circuit of above example of the present invention does not has the limit of input voltage for circuit designer
System, also will not be limited by load capacity, less with the resistance of the winding of debugging auxiliary repeatedly；Overcurrent protection
Circuit can regulate guard time, can protection circuit components and parts, short circuit or the overload to each road voltage timely
Play a very good protection, and the selection of parameter can be by being simply calculated.The most also may be used
To access overvoltage crowbar or other protection circuits.During the access of overvoltage crowbar, when feedback loop is opened a way
Or certain reason can block output when causing voltage to raise rapidly；Also for other need with high level or with
The circuit that low level signal is protected provides output high level or low level protection.
Claims (6)
1. a current foldback circuit, including sampling end and protection control signal output, it is characterised in that
Including anti-clutter circuit, output circuit and deadlock circuit, the input of anti-clutter circuit is described sampling end,
The input of the output termination output circuit of anti-clutter circuit, the output of output circuit is described protection control
Signal output part processed；The output controlling termination output circuit of deadlock circuit, the output termination of deadlock circuit
The control end of output circuit；When the voltage of sampling end exceedes setting value, anti-clutter circuit first carries out energy storage,
When the energy that anti-clutter circuit stores reaches setting value, output signal trigger output circuit output protection controls letter
Number；The protection control signal of output circuit output triggers deadlock circuit, and output signal is locked in by deadlock circuit
The output state of protection control signal；Anti-clutter circuit include a NPN triode, the first PNP triode,
Storage capacitor, discharge resistance and Zener diode, the colelctor electrode of a NPN triode is connect by the 3rd resistance
Power supply, the grounded emitter of a NPN triode, the base stage of a NPN triode is anti-clutter circuit
Input；The emitter stage of the first PNP triode connects power supply, and the colelctor electrode of the first PNP triode connects energy storage electricity
The first end held, the base stage of the first PNP triode connects the colelctor electrode of a NPN triode；Storage capacitor
Second end ground connection, discharge resistance is in parallel with storage capacitor；The negative electrode of Zener diode connects the first of storage capacitor
End, the anode of Zener diode is the output of anti-clutter circuit.
Current foldback circuit the most according to claim 1, it is characterised in that anti-clutter circuit includes
One resistance and the bleeder circuit of the second resistant series composition, the first end ground connection of bleeder circuit, the second end was
The sampling end of stream protection circuit, the tie point of the first resistance and the second resistance connects the base stage of a NPN triode.
Current foldback circuit the most according to claim 1, it is characterised in that anti-clutter circuit includes limit
Leakage resistance, the emitter stage of the first PNP triode connects power supply by current-limiting resistance.
Current foldback circuit the most according to claim 1, it is characterised in that output circuit includes second
NPN triode, the colelctor electrode of the 2nd NPN triode connects power supply by the 4th resistance, grounded emitter, base
Pole connects the output of anti-clutter circuit；The colelctor electrode of the 2nd NPN triode is the protection control of current foldback circuit
Signal output part processed.
Current foldback circuit the most according to claim 1, it is characterised in that deadlock circuit includes second
PNP triode, the emitter stage of the second PNP triode connects power supply, and colelctor electrode is as the output of deadlock circuit
Connecing the control end of output circuit, base stage is as the output controlling termination output circuit of deadlock circuit.
Current foldback circuit the most according to claim 1, it is characterised in that include main circuit, main electricity
Road includes control chip, switching tube and sampling resistor, and switching tube passes through sampling resistor ground connection, control chip
The control end of control signal output termination switching tube；The tie point of switching tube and sampling resistor is as sampled signal
Output connects the input of anti-clutter circuit, and the output of output circuit is as protection control signal output termination
The protection signal input part of control chip；During current foldback circuit output protection control signal, trigger main circuit
Control chip action, the output of closing switch pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310606159.3A CN103633616B (en) | 2013-11-25 | 2013-11-25 | A kind of current foldback circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310606159.3A CN103633616B (en) | 2013-11-25 | 2013-11-25 | A kind of current foldback circuit |
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| Publication Number | Publication Date |
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| CN103633616A CN103633616A (en) | 2014-03-12 |
| CN103633616B true CN103633616B (en) | 2016-09-07 |
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| CN201310606159.3A Active CN103633616B (en) | 2013-11-25 | 2013-11-25 | A kind of current foldback circuit |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103885382B (en) * | 2014-03-18 | 2017-01-25 | 深圳市汇川控制技术有限公司 | PLC output circuit with overcurrent protection |
| TWI588638B (en) * | 2015-11-09 | 2017-06-21 | 智原科技股份有限公司 | Anti-deadlock circuit for voltage regulator and associated power system |
| CN105680251A (en) * | 2016-01-15 | 2016-06-15 | 张月妹 | Over-current protection circuit for socket |
| CN107124576A (en) * | 2017-05-04 | 2017-09-01 | 安徽庆睿实业有限责任公司 | Video conference tele-control system |
| CN110890747B (en) * | 2019-11-29 | 2022-07-19 | 广东开利暖通空调股份有限公司 | Working circuit and overcurrent protection circuit thereof |
| CN113241940B (en) * | 2021-07-12 | 2021-09-10 | 上海芯龙半导体技术股份有限公司 | Overcurrent protection circuit and switching power supply chip |
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| CN101820162A (en) * | 2010-05-18 | 2010-09-01 | 北京星网锐捷网络技术有限公司 | Overcurrent protector |
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| CN103219706A (en) * | 2013-03-28 | 2013-07-24 | 深圳市安众电气有限公司 | IGBT (Insulated Gate Bipolar Transistor) over-current lock-in protection circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| TWI258909B (en) * | 2005-01-10 | 2006-07-21 | Cable Vision Electronics Co Lt | Overcurrent protection device |
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| CN101820162A (en) * | 2010-05-18 | 2010-09-01 | 北京星网锐捷网络技术有限公司 | Overcurrent protector |
| CN202309037U (en) * | 2011-09-28 | 2012-07-04 | 深圳麦格米特电气股份有限公司 | Cycle-by-cycle current protection circuit implemented by discrete devices |
| CN103219706A (en) * | 2013-03-28 | 2013-07-24 | 深圳市安众电气有限公司 | IGBT (Insulated Gate Bipolar Transistor) over-current lock-in protection circuit |
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| CN103633616A (en) | 2014-03-12 |
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