CN207530518U - Over-pressed short-circuit protection circuit - Google Patents
Over-pressed short-circuit protection circuit Download PDFInfo
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- CN207530518U CN207530518U CN201721766847.6U CN201721766847U CN207530518U CN 207530518 U CN207530518 U CN 207530518U CN 201721766847 U CN201721766847 U CN 201721766847U CN 207530518 U CN207530518 U CN 207530518U
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Abstract
The utility model discloses a kind of over-pressed short-circuit protection circuits; including the MOS switch being connected in series between power input and power output end; the current foldback circuit and overvoltage crowbar being serially connected between power input and power output end; the overvoltage crowbar detects power input terminal voltage; when power input electric voltage over press, control MOS switch shutdown.The utility model does overcurrent protection, overcurrent energy self- recoverage caused by short circuit, without frequently replacing fuse using resettable fuse.It using the characteristic of reference voltage chip CJ431, is monitored by the partial pressure to power supply, realizes overvoltage protection, extensively, voltage loss very little can effectively prevent artificial maloperation, greatly reduce loss protection voltage range (5.8 24V)；Indicating circuit facilitates failure judgement, and circuit is simple, at low cost.
Description
Technical field
The utility model belongs to power electronics field, and in particular to a kind of overvoltage short-circuit protection circuit.
Background technology
In electronic circuit, 5V and 12V power supplys are common power supplys.And in our test boards usually, in order to suitable
Different demands is answered, often has the test board of 5V power inputs and the test board of 12V power inputs.Correspondingly, power supply also has
Point of 5V and 12V.But the interface of power supply is the same, once the power supply of 12V has been inserted on the plank of 5V, if circuit into
Row is not protected, and plank will certainly be damaged.
Under normal conditions, people's custom realizes overvoltage protection using zener diode, and fuse realizes overcurrent protection.
But voltage-stabiliser tube and fuse protection is used to have as a drawback that：1st, overvoltage protection narrow range, zener diode have fixed
Breakdown voltage.If the 2nd, with the zener diode of 5V, accessing 12V power supply zener diodes itself will damage.If the 3rd, use 12V
Zener diode, the voltage between 5-12V can not respond or circuit can be damaged.Even if the 4th, two pole of voltage stabilizing
Pipe can protect, and equipment work will not stablize, and be not easy to find, once zener diode fails, circuit will damage
It is bad.5th, fuse can only be protected once, need to re-replace after blown fuse.
It is also protected using the power management chip of profession, but the power management chip of profession is with as follows
Shortcoming：1st, price is high, 2, the range of voltage protection it is also very limited because chip itself just has operating voltage requirement.If power supply
It can inherently be damaged more than chip operating voltage chip, not have protective effect.
Utility model content
It is simple, of low cost that the utility model technical issues that need to address are to provide a kind of circuit structure, voltage protection
The wide over-pressed short-circuit protection circuit of range.
To solve the above problems, technical solution adopted in the utility model is：
A kind of overvoltage short-circuit protection circuit, the MOS including being connected in series between power input and power output end are opened
It closes, the current foldback circuit and overvoltage crowbar being serially connected between power input and power output end, the overvoltage is protected
Protection circuit detects power input terminal voltage, when power input electric voltage over press, control MOS switch shutdown.
Further, the current foldback circuit is resettable fuse F1.
Further, the overvoltage crowbar includes resistance R2-R8, resistance R10, reference voltage chip U1, triode
Q3, wherein, reference voltage chip U1 is CJ431, and resistance R3, R6, R10, which are sequentially connected in series, to be followed by between input power VIN and ground,
Sampling end 1 foot of the connecting node of resistance R6, R10 through resistance R7 connection reference voltage chips U1,2 feet of reference voltage chip U1
Ground connection, base stage of 2 feet of reference voltage chip U1 through resistance R5 connecting triodes Q3,2 feet of reference voltage chip U1 are through resistance
The source S of R2 connection MOS switches, the source S of the emitter connection MOS switch of triode Q3, the collector of triode Q3 is through electricity
The source S of R4 connection MOS switches is hindered, the collector of triode Q3 is grounded through resistance R8.
Further, control source indicating circuit and voltage output indicating circuit are further included, the control source refers to
Show that circuit is connected in series in input electricity including light emitting diode D2 and current-limiting resistance R9, light emitting diode D2 and current-limiting resistance R9
Between source VIN and ground；Voltage output indicating circuit includes light emitting diode D1 and current-limiting resistance R1, light emitting diode D1 and limit
Leakage resistance R1 is connected in series between out-put supply Vout and ground.
Preferably, the MOS switch is two MOS switch pipes Q1, Q2 in parallel, the source electrode of MOS switch pipe Q1, drain electrode,
Source electrode, drain electrode, the grid of grid and MOS switch pipe Q2 are connected in parallel respectively.
It is using advantageous effect caused by above-mentioned technical proposal：
The utility model does overcurrent protection, overcurrent energy self- recoverage caused by short circuit, without frequent using resettable fuse
Replace fuse.It using the characteristic of reference voltage chip CJ431, is monitored by the partial pressure to power supply, realizes overvoltage protection,
Protect voltage range (5.8---24V) extensively, voltage loss very little can effectively prevent artificial maloperation, greatly reduce damage
It loses；Indicating circuit facilitates failure judgement, and circuit is simple, at low cost.
Description of the drawings
Fig. 1 is the utility model circuit block diagram；
Fig. 2 is one embodiment circuit diagram of the utility model；
Fig. 3 is another embodiment circuit diagram of the utility model.
Specific embodiment
Utility model is described in further detail below in conjunction with the accompanying drawings：
The utility model is a kind of over-pressed short-circuit protection circuit, and the utility model realizes overvoltage protection with simple circuit
Function, and voltage protection range is very wide, can protect the voltage between 5-15V completely.Even it can ensure 24V voltages
Input will not damage circuit.Only need common triode, reference voltage chip and several resistance etc. that can realize.Simultaneously
It using resettable fuse, can automatically disconnect the circuit when short circuit, when short circuit disappears, can restore automatically, without tearing machine open more
Change fuse.
As shown in Figure 1, the utility model includes power supply main circuit, current foldback circuit and overvoltage crowbar, wherein
Main circuit of powering is the MOS switch being connected in series between power input and power output end, and current foldback circuit is serially connected in
It detects and protects for overcurrent (short circuit) between power input and power output end, the overvoltage crowbar detection power supply is defeated
Enter terminal voltage, when power input electric voltage over press, control MOS switch shutdown.
Overcurrent protection is typically to prevent load short circuits from being impacted to power supply, selects fuse under normal circumstances to realize,
In order to reduce the trouble for replacing fuse, as shown in Fig. 2, the current foldback circuit is resettable fuse F1.
Overvoltage protection is to prevent input power excessively high, load is caused to burn or device over-voltage breakdown, as shown in Fig. 2, described
Overvoltage crowbar include resistance R2-R8, resistance R10, reference voltage chip U1, triode Q3, wherein, reference voltage chip U1
For CJ431, resistance R3, R6, R10, which are sequentially connected in series, to be followed by between input power VIN and ground, the connecting node warp of resistance R6, R10
1 foot of sampling end of resistance R7 connection reference voltage chips U1, the 2 feet ground connection of reference voltage chip U1, the 2 of reference voltage chip U1
Base stage of the foot through resistance R5 connecting triodes Q3, source S of 2 feet of reference voltage chip U1 through resistance R2 connection MOS switches, three
The source S of the emitter connection MOS switch of pole pipe Q3, source S of the collector of triode Q3 through resistance R4 connection MOS switches,
The collector of triode Q3 is grounded through resistance R8.
As shown in Fig. 2, the utility model further includes control source indicating circuit and voltage output indicating circuit, the electricity
Pressure input indicating circuit includes light emitting diode D2 and current-limiting resistance R9, and light emitting diode D2 and current-limiting resistance R9 are connected in series with
Between input power VIN and ground；Voltage output indicating circuit includes light emitting diode D1 and current-limiting resistance R1, light-emitting diodes
Pipe D1 and current-limiting resistance R1 are connected in series between out-put supply Vout and ground.
In order to improve the supply current of power supply, as shown in figure 3, the MOS switch of the utility model is opened for two MOS in parallel
Pipe Q1, Q2 are closed, source electrode, drain electrode, the grid of MOS switch pipe Q1 distinguish in parallel connect with source electrode, drain electrode, the grid of MOS switch pipe Q2
It connects.
Operation principle
Short-circuit protection：Supply voltage is inputted by VIN, first passes around resettable fuse F1.If the MOS switch of main circuit
Pipe Q1, Q2 or backend load find short circuit, and flowing through the electric current of fuse can drastically increase, and fuse can generate heat, then automatically
It cuts off the power.Fuse temperature can decline after short circuit is cancelled, and then reopen.
Overvoltage protection：CJ431 (U1) is a reference voltage chip, and internal there are one comparator, comparison voltage 2.5V.
Input power VIN compares after resistance R3, R6, R10 partial pressure with CJ431 builtin voltages.1 foot voltage=VIN* of CJ431
(R10/(R3+R6+R10)).When the 1 foot voltage of CJ431 is more than 2.5V, internal comparator can be triggered, forms 2 feet and 3 feet
Access makes the reduction of triode Q3 base voltages, and since triode Q3 is positive-negative-positive switching transistor, triode Q3 can be connected at this time,
The G poles of MOS switch pipe Q1 and Q2 can be raised.And MOS switch pipe Q1 and Q2 are P metal-oxide-semiconductors, belong to low level conducting type,
MOS switch pipe Q1, Q2 turns off, and power path is turned off, and protects late-class circuit.And when the 1 foot level of CJ431 is less than 2.5V,
CJ431 is not turned on, and the base stage of triode Q3 is drawn high by resistance R2.Triode Q3 is not turned on.The G poles of MOS switch pipe Q1, Q2
It is still low-voltage after being divided due to resistance R4, R8.MOS switch pipe Q1, Q2 is in the conduction state.
Light emitting diode D1, D2 play good indicative function.If light emitting diode D1, D2 are bright simultaneously, illustrate electricity
Road is working properly, if light emitting diode D1 does not work, light emitting diode D2 is bright, it is necessary to check circuit whether overvoltage protection.
If do not worked all, that illustrates that input power VIN is problematic.
In the utility model, resistance R3, R6, R10 are used for the partial pressure of input power VIN, can be by selecting suitable electricity
Resistance value meets protection requirement, if input power VIN is 5V, is more than 5.8V or so in voltage and realizes shutdown (CJ431 conductings).
According to the parameter of reference voltage chip CJ431 and metal-oxide-semiconductor, input voltage is until 24V can be protected well.
It is because 5V adapters will export the electricity of 5.5V or so when unloaded in itself why protection voltage, which takes 5.8V or so,
Pressure is to prevent protection circuit erroneous action.And the input power of 5.5V is in the attenuation by MOS switch pipe, filter circuit etc.
The voltage actually entered afterwards also can be in 5.5V hereinafter, will not damage circuit completely.
Claims (5)
1. a kind of overvoltage short-circuit protection circuit, it is characterised in that：Including be connected in series in power input and power output end it
Between MOS switch, the current foldback circuit and overvoltage crowbar being serially connected between power input and power output end, institute
Overvoltage crowbar detection power input terminal voltage is stated, when power input electric voltage over press, control MOS switch shutdown.
2. overvoltage short-circuit protection circuit according to claim 1, it is characterised in that the current foldback circuit is self- recoverage
Fuse F1.
3. overvoltage short-circuit protection circuit according to claim 1 or 2, it is characterised in that the overvoltage crowbar includes electricity
Hinder R2-R8, resistance R10, reference voltage chip U1, triode Q3, wherein, reference voltage chip U1 be CJ431, resistance R3, R6,
R10, which is sequentially connected in series, to be followed by between input power VIN and ground, and the connecting node of resistance R6, R10 are through resistance R7 connection reference voltages
1 foot of sampling end of chip U1, the 2 feet ground connection of reference voltage chip U1,2 feet of reference voltage chip U1 are through three pole of resistance R5 connections
The base stage of pipe Q3, source S of 2 feet of reference voltage chip U1 through resistance R2 connection MOS switches, the emitter connection of triode Q3
The source S of MOS switch, source S of the collector of triode Q3 through resistance R4 connection MOS switches, the collector warp of triode Q3
Resistance R8 is grounded.
4. it is according to claim 3 overvoltage short-circuit protection circuit, it is characterised in that further include control source indicating circuit with
And voltage output indicating circuit, the control source indicating circuit include light emitting diode D2 and current-limiting resistance R9, shine two
Pole pipe D2 and current-limiting resistance R9 are connected in series between input power VIN and ground；Voltage output indicating circuit includes light-emitting diodes
Pipe D1 and current-limiting resistance R1, light emitting diode D1 and current-limiting resistance R1 are connected in series between out-put supply Vout and ground.
5. according to 1,2,4 any one of them overvoltage short-circuit protection circuit of claim, it is characterised in that the MOS switch is two
MOS switch pipe Q1, Q2 of a parallel connection, the source electrode of MOS switch pipe Q1, drain electrode, grid and MOS switch pipe Q2 source electrode, drain electrode, grid
Pole is connected in parallel respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721766847.6U CN207530518U (en) | 2017-12-18 | 2017-12-18 | Over-pressed short-circuit protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721766847.6U CN207530518U (en) | 2017-12-18 | 2017-12-18 | Over-pressed short-circuit protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207530518U true CN207530518U (en) | 2018-06-22 |
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ID=62579124
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721766847.6U Active CN207530518U (en) | 2017-12-18 | 2017-12-18 | Over-pressed short-circuit protection circuit |
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| CN (1) | CN207530518U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110416968A (en) * | 2019-08-09 | 2019-11-05 | 无锡启腾电子科技有限公司 | A kind of electrical fuse and its working method |
| CN110867824A (en) * | 2019-12-18 | 2020-03-06 | 大唐半导体科技有限公司 | Power supply circuit for anti-explosion oil filling tax control machine |
| CN111105747A (en) * | 2019-12-30 | 2020-05-05 | 大峡谷照明系统（苏州）股份有限公司 | Drive circuit and display device |
| CN111313364A (en) * | 2019-11-29 | 2020-06-19 | 南通同洲电子有限责任公司 | Overvoltage protection device and overvoltage protection method |
| CN113078616A (en) * | 2021-04-02 | 2021-07-06 | 广东美电贝尔科技集团股份有限公司 | Rear-stage direct-current power supply circuit |
-
2017
- 2017-12-18 CN CN201721766847.6U patent/CN207530518U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110416968A (en) * | 2019-08-09 | 2019-11-05 | 无锡启腾电子科技有限公司 | A kind of electrical fuse and its working method |
| CN111313364A (en) * | 2019-11-29 | 2020-06-19 | 南通同洲电子有限责任公司 | Overvoltage protection device and overvoltage protection method |
| CN110867824A (en) * | 2019-12-18 | 2020-03-06 | 大唐半导体科技有限公司 | Power supply circuit for anti-explosion oil filling tax control machine |
| CN111105747A (en) * | 2019-12-30 | 2020-05-05 | 大峡谷照明系统（苏州）股份有限公司 | Drive circuit and display device |
| CN113078616A (en) * | 2021-04-02 | 2021-07-06 | 广东美电贝尔科技集团股份有限公司 | Rear-stage direct-current power supply circuit |
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