CN208158100U - A kind of output overvoltage protection circuit and the power supply comprising the circuit - Google Patents
A kind of output overvoltage protection circuit and the power supply comprising the circuit Download PDFInfo
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- CN208158100U CN208158100U CN201820585721.7U CN201820585721U CN208158100U CN 208158100 U CN208158100 U CN 208158100U CN 201820585721 U CN201820585721 U CN 201820585721U CN 208158100 U CN208158100 U CN 208158100U
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Abstract
The utility model provides a kind of output overvoltage protection circuit and the power supply comprising the circuit, output overvoltage protection circuit include：Threshold circuit, sample circuit, comparison circuit, control circuit and switching circuit；Threshold circuit is exported for generating threshold voltage to the first input end of comparison circuit；Sample circuit is used for the voltage of sample devices input port Vo, and generates sampled voltage and export to the second input terminal of comparison circuit；Comparison circuit exports control signal to the input terminal of control circuit for threshold voltage to be compared with sampled voltage；Turn-on and turn-off of the control circuit according to control signal control switch circuit；Two output ends of the utility model switching circuit are respectively used to connection equipment input port and output port of power source, so that being able to achieve equipment input port power supply stopping power supply to the device when over-voltage exception occurs, so that power supply and equipment are all protected.
Description
Technical field
The utility model relates to field of power supplies, specifically, being related to the output over-voltage protection of power supply.
Background technique
In power supply product of today, the various defencive functions of power supply can allow it to be applied in various environment, and can guarantee
The reliability of power supply product, output over-voltage protection function are one such defencive functions；Fig. 1 show existing output overvoltage and protects
The defencive function mechanism of protection circuit：Power source internal circuit or device are abnormal, cause output voltage to increase, to prevent power supply from exporting
Overtension and damage rear end equipment, to design output overvoltage protection circuit, export power remove when this occurs extremely
Or output clamper etc., not only it is avoided that rear end equipment is damaged because supply voltage (electric power output voltage) is excessively high, moreover it is possible to
Improve the reliability of power supply itself.
However above-mentioned protection mechanism is a kind of defencive function as caused by power source internal exception, protected object is to be powered
Equipment is a kind of abnormity of power supply and then the defencive function for protecting equipment, but equipment also can be abnormal, to influence power supply；So
The power supply power supply in industry does not fully take into account the baneful influence of power supply power supply application environment at present, and especially rear end equipment is given
Power supply bring influences；If rear end equipment is due to exception, the input port (output port of power source) of equipment is caused to generate a height
Voltage, greater than the input voltage of power supply power supply, cause to flow backward cause to power source internal the device of power supply output EMC circuit due to
Over-voltage and be damaged, and then abnormity of power supply, there are power supply aircraft bombing or the hidden danger of fire, the reliability of power supply drops significantly
Low, so now needing a kind of special output overvoltage protection circuit, protected object is power supply, improves the reliability of power supply power supply,
Avoid rear end equipment exception bring baneful influence.
Utility model content
In view of this, the utility model provides a kind of output overvoltage protection circuit and in view of the above problems comprising the circuit
Power supply, for controlling the output end of power supply power supply, to solve to improve to power supply power supply bring baneful influence after unit exception
The reliability of power supply.
The purpose of this utility model is achieved through the following technical solutions：
A kind of output overvoltage protection circuit, including：Threshold circuit, sample circuit, comparison circuit, control circuit and switch electricity
Road；
The input terminal of threshold circuit is for inputting supply voltage Vcc, and the of the output end connection comparison circuit of threshold circuit
One input terminal；The input terminal of sample circuit connects comparison circuit for connecting equipment input port Vo, the output end of sample circuit
The second input terminal；The input terminal of the output end connection control circuit of comparison circuit, the output end connection switch electricity of control circuit
The input terminal on road, the first output end of switching circuit are used for connecting equipment input port Vo, the second output terminal of switching circuit
In connection output port of power source Vo~；
Threshold circuit is exported for generating threshold voltage to the first input end of comparison circuit；
Sample circuit is used for the voltage of sample devices input port Vo, and generates sampled voltage and export to the of comparison circuit
Two input terminals；
Comparison circuit generates control signal and exports to control circuit for threshold voltage to be compared with sampled voltage
Input terminal；
Turn-on and turn-off of the control circuit according to control signal control switch circuit, when threshold voltage is greater than sampled voltage
When, switching circuit conducting, the second output terminal short circuit of the first output end and switching circuit of switching circuit；When threshold voltage is less than
When sampled voltage, switching circuit shutdown, the first output end of switching circuit and the second output terminal of switching circuit are opened a way.
As the first specific embodiment of threshold circuit, including two concatenated resistance, the one of first resistance
End is the input terminal of threshold circuit, and the other end of first resistance is grounded after second resistance, and the tie point of two resistance is
The output end of threshold circuit.
It is as second of specific embodiment of threshold circuit, including resistance and accurate source of stable pressure, one end of resistance
The input terminal of threshold circuit, shape after the reference end connection of the other end of resistance, the cathode of accurate source of stable pressure and accurate source of stable pressure
At the output end of threshold circuit, the plus earth of accurate source of stable pressure.
The improvement of the first and second of specific embodiment as above-mentioned threshold circuit, further includes a capacitor, electricity
The output end of one end connection threshold circuit of appearance, the other end ground connection of capacitor.
As a kind of specific embodiment of sample circuit, including two concatenated resistance, one end of first resistance
The other end for the input terminal of sample circuit, first resistance is grounded after second resistance, and the tie point of two resistance is to adopt
The output end of sample circuit.
It further include a capacitor as the improvement of above-mentioned sample circuit specific embodiment, one end of capacitor connects sampling
The output end of circuit, the other end ground connection of capacitor.
It is as a kind of specific embodiment of comparison circuit, including a comparator, the reverse input end of comparator
The first input end of comparison circuit, the noninverting input of comparator are the second input terminal of comparison circuit, the output end of comparator
For the output end of comparison circuit.
As a kind of specific embodiment of control circuit, including a triode, the base stage of triode is control electricity
The input terminal on road, the output end of the current collection of triode extremely control circuit, the emitter ground connection of triode.
It further include two resistance and a capacitor, wherein one as the improvement of above-mentioned control circuit specific embodiment
Resistance is connected between the base stage of triode and the input terminal of control circuit, in addition a resistance be connected to the base stage of triode with
Between the emitter of triode, capacitance connection is between the emitter of triode and the input terminal of control circuit.
As a kind of specific embodiment of switching circuit, including a metal-oxide-semiconductor, the grid of metal-oxide-semiconductor is switching circuit
Input terminal, the drain electrode of metal-oxide-semiconductor is the first output end of switching circuit, and the source electrode of metal-oxide-semiconductor is the second output terminal of switching circuit.
It further include a resistance as the improvement of said switching circuit specific embodiment, resistance is connected to switch electricity
It the input terminal on road and is provided in the route of supply voltage for switching circuit.
It as an improvement of the above technical solution, further include return difference circuit, the input terminal connection sample circuit of return difference circuit
Output end, the output end of the output end connection comparison circuit of return difference circuit, return difference circuit is for generating hysteresis voltage, so that comparing
There are return differences for the overturning of circuit output control signal.
It is a resistance as a kind of specific embodiment of return difference circuit.
As an improvement of the above technical solution, also packet anti-clutter circuit, anti-clutter circuit are connected to the output of comparison circuit
Between end and the input terminal of control circuit.
It is a diode as a kind of specific embodiment of anti-clutter circuit, the anode connection of diode is compared
The output end of circuit, the input terminal of the cathode connection control circuit of diode.
Power technology scheme comprising above-mentioned output overvoltage protection circuit is：First output end of switching circuit forms power supply
A port, the port is for connecting equipment input port Vo；The second output terminal of switching circuit connects output port of power source
Vo~.
Term is explained：
Hysteresis voltage：It is exactly that the point of control is become section that purpose, which is arranged, in hysteresis voltage, if working as sampled voltage without return difference
Around threshold voltage when fluctuating change, comparison circuit outputs control signals to conducting and the pass of control circuit control switch circuit
It is disconnected just ceaselessly to change, there is great damage to equipment.
Citing：Threshold voltage is set as 1.0V, and hysteresis voltage is set as 0.1V, then when sampled voltage is increased beyond 1.0V
When, control signal to the control circuit control switch circuit of comparison circuit output turns off, and when sampled voltage returns to 0.9V, compares
The control signal of circuit ability output switching activity to control circuit control switch circuit is connected.
The working principle of the utility model will be analyzed in conjunction with specific embodiment, and compared with prior art, this is practical
It is novel to have the advantages that：
1) the utility model proposes a kind of completely new protection thinkings, while improving the reliability of power supply and equipment；
2) the utility model circuit is simple, easily designed, at low cost convenient for debugging.
Detailed description of the invention
Fig. 1 is the defencive function mechanism of existing output overvoltage protection circuit；
Fig. 2 is the defencive function mechanism of the utility model output overvoltage protection circuit；
Fig. 3 is the functional block diagram of the utility model output overvoltage protection circuit；
Fig. 4 is the schematic diagram of the utility model output overvoltage protection circuit first embodiment；
Fig. 5 is the schematic diagram of the utility model output overvoltage protection circuit second embodiment.
Specific embodiment
Fig. 2 is the functional block diagram defencive function mechanism of the utility model output overvoltage protection circuit, is existed with Fig. 1 difference
In：The utility model occurs abnormal situation from equipment, while considering the protection problem of power supply and equipment, thereby produces
The utility model of the utility model is conceived, as：The voltage of sample devices input port Vo, is controlled after being compared with threshold voltage
Whether connected between power supply processed and equipment, to realize that power supply stops supplying to equipment when over-voltage exception occurs in equipment input port
Electricity, so that power supply and equipment are all protected.
It should be noted that the power supply using the utility model output overvoltage protection circuit can retain background when implementing
Existing output overvoltage protection circuit described in technology, so that the reliability of the system of power supply and equipment composition is strengthened.
Fig. 3 show the principles of the present invention block diagram, including：Threshold circuit, sample circuit, comparison circuit, control electricity
Road and switching circuit；The input terminal of threshold circuit connects comparison circuit for inputting supply voltage Vcc, the output end of threshold circuit
First input end；The input terminal of sample circuit compares for connecting equipment input port Vo, the output end connection of sample circuit
Second input terminal of circuit；The input terminal of the output end connection control circuit of comparison circuit, the output end connection of control circuit are opened
The input terminal on powered-down road, the first output end of switching circuit is for connecting equipment input port Vo, the second output of switching circuit
End for connect output port of power source Vo~.
Threshold circuit in Fig. 2 functional block diagram is exported for generating threshold voltage to the first input end of comparison circuit；
Sample circuit is used for the voltage of sample devices input port Vo, and generates sampled voltage and export to the second input of comparison circuit
End；Comparison circuit generates control signal and exports to the defeated of control circuit for threshold voltage to be compared with sampled voltage
Enter end；Turn-on and turn-off of the control circuit according to control signal control switch circuit are opened when threshold voltage is greater than sampled voltage
Powered-down road conducting, the second output terminal short circuit of the first output end and switching circuit of switching circuit；When threshold voltage is less than sampling
When voltage, switching circuit shutdown, the first output end of switching circuit and the second output terminal of switching circuit are opened a way.
It is with reference to the accompanying drawings and embodiments, further to the utility model in order to which the utility model is more clearly understood
It is described in detail.It should be appreciated that specific embodiment described herein is only used to explain the utility model, it is not used to limit this
Utility model.
First embodiment
Fig. 3 show the schematic diagram of the utility model output overvoltage protection circuit first embodiment.
Threshold circuit includes two concatenated resistance, and one end of first resistance R1 is the input terminal of threshold circuit, and first
The other end of resistance R1 is grounded after second resistance R4, and the tie point of two resistance is the output end of threshold circuit；Threshold value
Circuit further includes a capacitor C1, and capacitor C1 is in parallel with resistance R4, and capacitor C1 is used to filter out the interference voltage in threshold circuit.
Sample circuit includes two concatenated resistance, and one end of first resistance R2 is the input terminal of sample circuit, and first
The other end of resistance R2 is grounded after second resistance R3, and the tie point of two resistance is the output end of sample circuit；Sampling
Circuit further includes a capacitor C2, and capacitor C2 is in parallel with resistance R3, and capacitor C2 is used to filter out the interference voltage in sample circuit.
Comparison circuit is a comparator U2A, and the reverse input end of comparator U2A is the first input end of comparison circuit,
The noninverting input of comparator U2A is the second input terminal of comparison circuit, and the output end of comparator U2A is the output of comparison circuit
End.
Control circuit includes a triode Q1, and the base stage of triode Q1 is the input terminal of control circuit, triode Q1's
The output end of current collection extremely control circuit, the emitter ground connection of triode Q1；Control circuit further includes two resistance and an electricity
Hold, wherein a resistance R5 is connected between the base stage of triode Q1 and the input terminal of control circuit, resistance R5 is for limiting three
The base current of pole pipe Q1, in addition a resistance R6 is connected between the base stage of triode Q1 and the emitter of triode Q1, electricity
The effect of resistance R6 is to ensure that triode Q1 energy reliable turn-off, capacitor C3 are connected to the emitter and control circuit of triode Q1
Input terminal between, capacitor C3 is used to filter out interference voltage in sample circuit.
Switching circuit includes a metal-oxide-semiconductor TR1, and the grid of metal-oxide-semiconductor TR1 is the input terminal of switching circuit, metal-oxide-semiconductor TR1's
Drain electrode is the first output end of switching circuit, and the source electrode of metal-oxide-semiconductor TR1 is the second output terminal of switching circuit；Switching circuit also wraps
A resistance R8 is included, resistance R8 is connected to the input terminal of switching circuit and provides in the route of supply voltage for switching circuit.
In addition, the present embodiment further includes return difference circuit, return difference circuit is a resistance R9.
The principle Analysis of the present embodiment is as follows：
When power initiation or normal work, the threshold voltage of comparator inverting input terminal input is always more than comparator
The output end of the sampled voltage of normal phase input end input, comparator is low level, and triode Q1 is in off state, supply voltage
Vcc provides driving voltage for metal-oxide-semiconductor TR1, i.e. the grid of metal-oxide-semiconductor TR1 is high level, and metal-oxide-semiconductor TR1 is in the conductive state, equipment
Input port Vo and output port of power source Vo~and to be short-circuit, electric power output voltage power supply to the device works normally, so this circuit
It will not influence the starting and normal work of power supply and equipment；When power supply rear end equipment is due to the abnormal voltage for leading to input port Vo
When raising, sampled voltage is also persistently increased, when sampled voltage is greater than threshold voltage, i.e. the voltage of the normal phase input end of comparator
Greater than the voltage of inverting input terminal, the output end of comparator exports high level, the work of return difference circuit, while triode Q1 is connected,
The grid voltage of metal-oxide-semiconductor TR1 is dragged down, metal-oxide-semiconductor TR1 shutdown, equipment input port Vo and output port of power source Vo~to open
Road, i.e. output port of power source Vo~and equipment input port Vo are disconnected, and then protect power supply, improve the reliability of power supply.
Resistance R9 in the present embodiment in return difference circuit can connect with the divider resistance R2 of sample circuit, to be formed
Hysteresis voltage；Such as when sampled voltage is greater than threshold voltage, comparison circuit exports the control signal of high level, return difference circuit work
Make, the resistance R9 in return difference circuit connects with the divider resistance R2 in sample circuit, and resistance value becomes larger, and sampled voltage further increases
Hysteresis voltage is formed, guarantees that comparator reliably exports the control signal of high level, prevents jitter error from sending out；Vice versa, returns
Difference circuit can guarantee that comparator reliably exports low level control signal, prevent jitter error from sending out.
Second embodiment
Fig. 2 show the schematic diagram and first embodiment phase of the utility model output overvoltage protection circuit second embodiment
Than difference is：Resistance R4 has been changed to accurate source of stable pressure U1, using accurate source of stable pressure, the more stable standard of threshold voltage
Really, it is avoided that the voltage of equipment input port Vo because disturbance fluctuation influences threshold voltage, causes comparison circuit error to be sent out, protection
The reliability of circuit is further promoted, and accurate source of stable pressure uses common 431.
The circuit operation principle is consistent with first embodiment, and details are not described herein.
Above are merely preferred embodiments of the utility model, it is noted that above-mentioned preferred embodiment should not regard
For the limitation of the utility model, on the basis of the utility model Fig. 3 functional block diagram, for the ordinary skill people of the art
Member for, without departing from the spirit and scope of the utility model, can also make it is alternatively improved and retouching, these improve and
Retouching is no longer repeated with embodiment here also in the protection scope of the utility model, and the protection scope of the utility model should be with
Subject to claim limited range.
Claims (14)
1. a kind of output overvoltage protection circuit, it is characterised in that：Including：Threshold circuit, sample circuit, comparison circuit, control electricity
Road and switching circuit；
For the input terminal of threshold circuit for inputting supply voltage Vcc, the first of the output end connection comparison circuit of threshold circuit is defeated
Enter end；The input terminal of sample circuit is for connecting equipment input port Vo, and the of the output end connection comparison circuit of sample circuit
Two input terminals；The input terminal of the output end connection control circuit of comparison circuit, the output end connection switch circuit of control circuit
Input terminal, the first output end of switching circuit is for connecting equipment input port Vo, and the second output terminal of switching circuit is for connecting
Meet output port of power source Vo~；
Threshold circuit is exported for generating threshold voltage to the first input end of comparison circuit；Sample circuit is set for sampling
The voltage of standby input port Vo, and generate sampled voltage and export to the second input terminal of comparison circuit；
Comparison circuit generates control signal and exports to the defeated of control circuit for threshold voltage to be compared with sampled voltage
Enter end；Turn-on and turn-off of the control circuit according to control signal control switch circuit are opened when threshold voltage is greater than sampled voltage
Powered-down road conducting, the second output terminal short circuit of the first output end and switching circuit of switching circuit；When threshold voltage is less than sampling
When voltage, switching circuit shutdown, the first output end of switching circuit and the second output terminal of switching circuit are opened a way.
2. output overvoltage protection circuit according to claim 1, it is characterised in that：Threshold circuit includes two concatenated electricity
Resistance, one end of first resistance are the input terminal of threshold circuit, and the other end of first resistance is grounded after second resistance, two
The tie point of resistance is the output end of threshold circuit.
3. output overvoltage protection circuit according to claim 1, it is characterised in that：Threshold circuit includes resistance and precisely steady
Potential source, one end of resistance are the input terminal of threshold circuit, the cathode and accurate source of stable pressure of the other end of resistance, accurate source of stable pressure
Reference end connection after formed threshold circuit output end, the plus earth of accurate source of stable pressure.
4. output overvoltage protection circuit according to claim 2 or 3, it is characterised in that：Threshold circuit further includes an electricity
Hold, the output end of one end connection threshold circuit of capacitor, the other end ground connection of capacitor.
5. output overvoltage protection circuit according to claim 1, it is characterised in that：Sample circuit includes two concatenated electricity
Resistance, one end of first resistance are the input terminal of sample circuit, and the other end of first resistance is grounded after second resistance, two
The tie point of resistance is the output end of sample circuit.
6. output overvoltage protection circuit according to claim 5, it is characterised in that：Sample circuit further includes a capacitor,
The output end of one end connection sample circuit of capacitor, the other end ground connection of capacitor.
7. output overvoltage protection circuit according to claim 1, it is characterised in that：Comparison circuit includes a comparator,
The reverse input end of comparator is the first input end of comparison circuit, and the noninverting input of comparator is the second defeated of comparison circuit
Enter end, the output end of comparator is the output end of comparison circuit.
8. output overvoltage protection circuit according to claim 1, it is characterised in that：Control circuit includes a triode,
The base stage of triode is the input terminal of control circuit, the output end of the current collection of triode extremely control circuit, the transmitting of triode
Pole ground connection.
9. output overvoltage protection circuit according to claim 8, it is characterised in that：Control circuit further include two resistance and
One capacitor, wherein a resistance is connected between the base stage of triode and the input terminal of control circuit, in addition a resistance connects
It connects between the base stage of triode and the emitter of triode, capacitance connection is in the emitter of triode and the input of control circuit
Between end.
10. output overvoltage protection circuit according to claim 1, it is characterised in that：Switching circuit includes a metal-oxide-semiconductor,
The grid of metal-oxide-semiconductor is the input terminal of switching circuit, and the drain electrode of metal-oxide-semiconductor is the first output end of switching circuit, and the source electrode of metal-oxide-semiconductor is
The second output terminal of switching circuit.
11. output overvoltage protection circuit according to claim 10, it is characterised in that：Switching circuit further includes an electricity
Resistance, resistance are connected to the input terminal of switching circuit and provide in the route of supply voltage for switching circuit.
12. output overvoltage protection circuit according to claim 1, it is characterised in that：It further include return difference circuit, return difference circuit
Input terminal connection sample circuit output end, return difference circuit output end connection comparison circuit output end, return difference circuit use
In generating hysteresis voltage, so that there are return differences for the overturning of comparison circuit output control signal.
13. output overvoltage protection circuit according to claim 12, it is characterised in that：Return difference circuit is a resistance.
14. a kind of power supply comprising the described in any item output overvoltage protection circuits of claim 1 to 13, it is characterised in that：It opens
First output end on powered-down road forms a port of power supply, and the port is for connecting equipment input port Vo；Switching circuit
Second output terminal connects output port of power source Vo~。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820585721.7U CN208158100U (en) | 2018-04-24 | 2018-04-24 | A kind of output overvoltage protection circuit and the power supply comprising the circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820585721.7U CN208158100U (en) | 2018-04-24 | 2018-04-24 | A kind of output overvoltage protection circuit and the power supply comprising the circuit |
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| Publication Number | Publication Date |
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| CN208158100U true CN208158100U (en) | 2018-11-27 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201820585721.7U Active CN208158100U (en) | 2018-04-24 | 2018-04-24 | A kind of output overvoltage protection circuit and the power supply comprising the circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108429239A (en) * | 2018-04-24 | 2018-08-21 | 广州金升阳科技有限公司 | A kind of output overvoltage protection circuit and the power supply comprising the circuit |
| CN110854991A (en) * | 2019-11-29 | 2020-02-28 | 苏州浪潮智能科技有限公司 | Power supply control circuit |
-
2018
- 2018-04-24 CN CN201820585721.7U patent/CN208158100U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108429239A (en) * | 2018-04-24 | 2018-08-21 | 广州金升阳科技有限公司 | A kind of output overvoltage protection circuit and the power supply comprising the circuit |
| CN110854991A (en) * | 2019-11-29 | 2020-02-28 | 苏州浪潮智能科技有限公司 | Power supply control circuit |
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