CN205901252U - Novel current foldback circuit - Google Patents
Novel current foldback circuit Download PDFInfo
- Publication number
- CN205901252U CN205901252U CN201620612253.9U CN201620612253U CN205901252U CN 205901252 U CN205901252 U CN 205901252U CN 201620612253 U CN201620612253 U CN 201620612253U CN 205901252 U CN205901252 U CN 205901252U
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- resistance
- triode
- operational amplifier
- mos pipe
- circuit
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Abstract
The utility model discloses a novel current foldback circuit, including drive circuit and power output end, still be equipped with current foldback circuit, current foldback circuit includes first resistance, second resistance, third resistance, fourth resistance, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, triode, MOS pipe, unidirectional diode, operational amplifier and electric capacity. The end face polishing device for the workpiece has a simple structure, the pressure ratio uses stabilizing the voltage to contrast, consequently, it is more stable to overflow electric current point relative ratio, solved and overflowed the great technique of electric current point fluctuation in the conventional art inadequately, unidirectional diode's afterflow effect makes operational amplifier's the value that positive output is proper keep for the high level, the triode keeps switching on, MOS manages keep cut -off, the main current can't switch on once more, thereby the safety of device has been protected, make the circuit have the restorability protection, solved and caused the circuit repeated the technological not enough of shutoff that switch on to appear because of the short circuit condition appears in driving part easily in the conventional art.
Description
Technical field
The utility model is related to current foldback circuit technical field, particularly to a kind of new current foldback circuit.
Background technology
In electronic application, can there is device and abnormal conditions occur, the situation leading to electric current excessive or short circuit occurring, if
If unprotected effect on wiring board, it will expendable destruction is produced to other elements of wiring board, or even causes fire
Calamity.It is thus desirable to adding current foldback circuit on drive circuit, but when it abnormal, protection can be made, make it quickly close
Disconnected protection circuit.Conventional current foldback circuit is as shown in Figure 1.
Resistance r2 is the resistance of less resistance, and the principal current of drive part all can pass through this resistance under normal circumstances, works as drive
Dynamic part occurs extremely making principal current increase, and when increasing to certain value, that is, resistance r2 both end voltage is more than the be end of triode q2
When opening threshold values, the ce end conducting of triode q2, make the grid g pole tension of FET q3 be close to 0, that is, FET will
Close, principal current will turn off.
But there is some shortcoming in this circuit: the be end of each triode q2 is opened threshold values and had differences, therefore excessively stream electricity
Flow point fluctuation is larger；After excessively stream switch off current, resistance r2 equally can make triode q2 quit work because losing electric current, field
Effect pipe will be again turned on, if when short circuit in drive part, circuit will duplicate the situation that conducting turns off,
Certain risk is all equally existed in the case of being somebody's turn to do.
Utility model content
Main purpose of the present utility model is to provide a kind of new current foldback circuit, and its structure is simple, can effectively solving
In conventional art, overcurrent point fluctuation is larger and easily causes circuit to duplicate because drive part short-circuit conditions
The technical deficiency that conducting turns off..
The utility model proposes a kind of new current foldback circuit, it is connected including drive circuit with described drive circuit
Power output end, be additionally provided with current foldback circuit, described current foldback circuit include first resistor, second resistance, the 3rd electricity
Resistance, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, triode, mos pipe, unilateral diode, computing
Amplifier and electric capacity, the output end of described operational amplifier is connected in the base stage of triode by first resistor, described three poles
The colelctor electrode of pipe is connected with the grid of mos pipe, and the drain electrode of described mos pipe is connected with drive circuit, the source electrode of described mos pipe
By second resistance ground wire, the grid of described mos pipe is connected on the source electrode of mos pipe in succession by 3rd resistor, described three poles
The emitter stage of pipe is connected on the source electrode of mos pipe, and the base stage of described triode is connected to the source electrode of mos pipe by the 4th resistance
On, the colelctor electrode of described triode is connected to fixed power source input by the 5th resistance, described 6th resistance and the 7th resistance
It is connected to after series connection between fixed power source input and ground wire, the negative input of described operational amplifier is connected to the 6th resistance
On the tie point of the 7th resistance, the electrode input end of described operational amplifier passes through capacity earth line, described unilateral diode
The output end of operational amplifier that connects of positive pole, negative pole be connected to the electrode input end of operational amplifier, described 8th resistance
One end be connected to the electrode input end of operational amplifier, the other end is connected on the emitter stage of triode.
Described mos manages as N-shaped mos pipe.
Described triode is npn triode.
Model lm358 of described operational amplifier.
Structure of the present utility model is simple, pressure comparison point is contrasted using burning voltage, and therefore overcurrent point is relative
More stable, can the larger technical deficiency of overcurrent point fluctuation in effectively solving conventional art, and be provided with unidirectional two poles
The afterflow effect of pipe makes the positive value of the cathode output end of operational amplifier remain high level, and triode is held on, and mos pipe is protected
Hold cut-off, principal current cannot turn on again, thus protecting the safety of device, protecting other circuit simultaneously, making circuit have
Restorability is protected, and solves in conventional art and easily causes circuit to duplicate conducting because drive part short-circuit conditions
The technical deficiency turning off, stability in use is good and strong applicability.
Brief description
Fig. 1 is the current foldback circuit structural representation of prior art；
Fig. 2 is embodiment schematic diagram of the present utility model.
The realization of the utility model purpose, functional characteristics and advantage will be described further in conjunction with the embodiments referring to the drawings.
Specific embodiment
It should be appreciated that specific embodiment described herein, only in order to explain the utility model, is not used to limit this
Utility model.
With reference to Fig. 2, an embodiment of the present utility model is proposed, a kind of new current foldback circuit, including drive circuit 1
And the power output end 2(vcc being connected with described drive circuit 1), it is additionally provided with current foldback circuit 3, described overcurrent protection electricity
Road 3 include first resistor r1, second resistance r2,3rd resistor r3, the 4th resistance r4, the 5th resistance r5, the 6th resistance r6, the 7th
Resistance r7, the 8th resistance r8, triode q1, mos pipe q2, unilateral diode d1, operational amplifier u1 and electric capacity c, described computing
The output end of amplifier u1 is connected in the base stage of triode q1 by first resistor r1, the colelctor electrode of described triode q1 with
The grid of mos pipe q2 is connected, and the drain electrode of described mos pipe q2 is connected with drive circuit 1, and the source electrode of described mos pipe q2 passes through
Second resistance r2 ground wire, the grid of described mos pipe q2 is connected on the source electrode of mos pipe q2 in succession by 3rd resistor r3, described
The emitter stage of triode q1 is connected on the source electrode of mos pipe q2, and the base stage of described triode q1 is connected to by the 4th resistance r4
On the source electrode of mos pipe q2, the colelctor electrode of described triode q1 is connected to fixed power source input vdd, institute by the 5th resistance r5
State after the 6th resistance r6 is connected with the 7th resistance r7 and be connected between fixed power source input vdd and ground wire, described operation amplifier
The negative input of device u1 is connected on the tie point of the 6th resistance r6 and the 7th resistance r7, the positive pole of described operational amplifier u1
Input passes through electric capacity c ground wire, and the output end of operational amplifier u1 of positive pole connection of described unilateral diode d1, negative pole are even
It is connected on the electrode input end of operational amplifier u1, one end of described 8th resistance r8 is connected to the positive pole input of operational amplifier u1
End, the other end are connected on the emitter stage of triode q1.
Described mos manages as N-shaped mos pipe.
Described triode is npn triode.
Model lm358 of described operational amplifier.
The principal current of drive part also passes through resistance r2, and the magnitude of voltage at resistance r2 two ends is equivalent to the magnitude of voltage of v+,
Simultaneously because vdd is a fixed voltage value, therefore through the partial pressure of r6 and r7, the magnitude of voltage of v- point is similarly a fixing electricity
Pressure value.When principal current normal work, during less than overcurrent protection current value, point v+ magnitude of voltage is less than point v- magnitude of voltage, therefore point v0
For low level output, therefore triode q1 is cut-off, FET q2 grid g extremely high level, FET normal work.
Increase when principal current electric current moment, when exceeding overcurrent protection current value, point v+ magnitude of voltage is higher than point v-, therefore point v0
For high level output, therefore triode q1 is conducting state, and FET q2 is cut-off state, turns off principal current.
Although principal current turns off, due to the effect of diode d1, the high level of v0 output by diode d1 continue to
R8 and r2 powers, and makes the magnitude of voltage of point v+ remain state more than v-, triode q1 continues to be held on simultaneously, and field
Effect pipe q2 keeps cut-off state, and principal current remains shutoff.
Structure of the present utility model is simple, pressure comparison point is contrasted using burning voltage, and therefore overcurrent point is relative
More stable, can the larger technical deficiency of overcurrent point fluctuation in effectively solving conventional art, and be provided with unidirectional two poles
The afterflow effect of pipe makes the positive value of the cathode output end of operational amplifier remain high level, and triode is held on, and mos pipe is protected
Hold cut-off, principal current cannot turn on again, thus protecting the safety of device, protecting other circuit simultaneously, making circuit have
Restorability is protected, and solves in conventional art and easily causes circuit to duplicate conducting because drive part short-circuit conditions
The technical deficiency turning off, stability in use is good and strong applicability.
The foregoing is only preferred embodiment of the present utility model, not thereby limit the scope of the claims of the present utility model,
The equivalent structure transformation that every utilization the utility model specification and accompanying drawing content are made, or directly or indirectly it is used in other phases
The technical field closed, is all included in the same manner in scope of patent protection of the present utility model.
Claims (3)
1. a kind of new current foldback circuit, the power output end be connected including drive circuit and with described drive circuit, its
Be characterised by: be additionally provided with current foldback circuit, described current foldback circuit include first resistor, second resistance, 3rd resistor,
Four resistance, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, triode, mos pipe, unilateral diode, operational amplifier
And electric capacity, the output end of described operational amplifier is connected in the base stage of triode by first resistor, the collection of described triode
Electrode is connected with the grid of mos pipe, and the drain electrode of described mos pipe is connected with drive circuit, and the source electrode of described mos pipe passes through the
Two resistance eutral grounding lines, the grid of described mos pipe is connected on the source electrode of mos pipe in succession by 3rd resistor, described triode send out
Emitter-base bandgap grading is connected on the source electrode of mos pipe, and the base stage of described triode is connected on the source electrode of mos pipe by the 4th resistance, described
The colelctor electrode of triode is connected to fixed power source input by the 5th resistance, connects after described 6th resistance and the 7th resistant series
It is connected between fixed power source input and ground wire, the negative input of described operational amplifier is connected to the 6th resistance and the 7th electricity
On the tie point of resistance, the electrode input end of described operational amplifier passes through capacity earth line, and the positive pole of described unilateral diode is even
The output end of the operational amplifier connecing, negative pole are connected to the electrode input end of operational amplifier, and one end of described 8th resistance is even
It is connected on the electrode input end of operational amplifier, the other end is connected on the emitter stage of triode；Described mos manages as N-shaped mos pipe.
2. new current foldback circuit according to claim 1 it is characterised in that: described triode be npn triode.
3. new current foldback circuit according to claim 2 it is characterised in that: the model of described operational amplifier
lm358.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620612253.9U CN205901252U (en) | 2016-06-21 | 2016-06-21 | Novel current foldback circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620612253.9U CN205901252U (en) | 2016-06-21 | 2016-06-21 | Novel current foldback circuit |
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| Publication Number | Publication Date |
|---|---|
| CN205901252U true CN205901252U (en) | 2017-01-18 |
Family
ID=57767096
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620612253.9U Active CN205901252U (en) | 2016-06-21 | 2016-06-21 | Novel current foldback circuit |
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| CN (1) | CN205901252U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107395175A (en) * | 2017-09-04 | 2017-11-24 | 云南电网有限责任公司电力科学研究院 | A kind of metal-oxide-semiconductor current foldback circuit |
| CN107745688A (en) * | 2017-10-13 | 2018-03-02 | 陈木镇 | A kind of system suitable for automobile communication |
| CN108259826A (en) * | 2018-01-03 | 2018-07-06 | 广州爱易学智能信息科技有限公司 | The image acquisition transmission system of multiple images is shown in same picture |
| CN108336715A (en) * | 2017-12-21 | 2018-07-27 | 长沙拓扑陆川新材料科技有限公司 | A kind of current foldback circuit |
| CN109474361A (en) * | 2018-12-06 | 2019-03-15 | 广州荣锋电子科技有限公司 | Sound console |
-
2016
- 2016-06-21 CN CN201620612253.9U patent/CN205901252U/en active Active
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107395175A (en) * | 2017-09-04 | 2017-11-24 | 云南电网有限责任公司电力科学研究院 | A kind of metal-oxide-semiconductor current foldback circuit |
| CN107395175B (en) * | 2017-09-04 | 2023-09-22 | 云南电网有限责任公司电力科学研究院 | MOS tube overcurrent protection circuit |
| CN107745688A (en) * | 2017-10-13 | 2018-03-02 | 陈木镇 | A kind of system suitable for automobile communication |
| CN108336715A (en) * | 2017-12-21 | 2018-07-27 | 长沙拓扑陆川新材料科技有限公司 | A kind of current foldback circuit |
| CN108259826A (en) * | 2018-01-03 | 2018-07-06 | 广州爱易学智能信息科技有限公司 | The image acquisition transmission system of multiple images is shown in same picture |
| CN108259826B (en) * | 2018-01-03 | 2020-05-22 | 广州英龙教育设备有限公司 | Image acquisition and transmission system for displaying multiple images on same picture |
| CN109474361A (en) * | 2018-12-06 | 2019-03-15 | 广州荣锋电子科技有限公司 | Sound console |
| CN109474361B (en) * | 2018-12-06 | 2020-05-19 | 广州荣锋电子科技有限公司 | Sound console |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |