CN103944140B - Alternating-current input overvoltage protection circuit - Google Patents
Alternating-current input overvoltage protection circuit Download PDFInfo
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- CN103944140B CN103944140B CN201410078392.3A CN201410078392A CN103944140B CN 103944140 B CN103944140 B CN 103944140B CN 201410078392 A CN201410078392 A CN 201410078392A CN 103944140 B CN103944140 B CN 103944140B
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- 238000002955 isolation Methods 0.000 claims abstract description 29
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- 230000003321 amplification Effects 0.000 claims description 8
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Abstract
The present invention provides a kind of alternating-current input overvoltage protection circuit; including exchange isolation detection unit, absolute value amplifying unit, crest voltage sampling unit and overvoltage return difference unit; wherein, the AC input cell received is converted into low-voltage and passes to absolute value amplifying unit by described alternating voltage isolation detection unit；Low voltage signal is taken absolute value after amplifying and exports to peak value sampling unit by absolute value amplifying unit；Voltage signal after peak value sampling unit will amplify takes peak value and exports to overvoltage return difference unit；Crest voltage is compared by overvoltage return difference unit with predeterminated voltage, outputs level signals；The present invention, by adding overvoltage return difference unit in alternating-current input overvoltage protection circuit, makes protection circuit action repeatedly do not occur because of voltage pulsation, it is ensured that the reliability service of power supply.
Description
Technical field
The present invention relates to a kind of exchange overvoltage crowbar, particularly relate to a kind of single-phase AC voltage input overvoltage protection
Circuit.
Background technology
Overvoltage crowbar is a kind of Important Circuit for protecting power supply, when input voltage is beyond the trouble free service of power supply
During voltage, overvoltage circuit action, to ensure that power supply is not damaged by.Current protection circuit, the most protected circuit perseveration；
Meanwhile, AC-input voltage recover normal after, circuit can not automatic recovery of power supply timely, affect powering in time of power supply.
Summary of the invention
The shortcoming of prior art in view of the above, it is an object of the invention to provide a kind of exchange input overvoltage protection electricity
Road, is used for solving overvoltage crowbar of the prior art and there is perseveration and recover normal rear circuit at AC-input voltage
Can not the problem of automatic recovery of power supply timely.
For achieving the above object and other relevant purposes, the present invention provides techniques below scheme:
A kind of alternating-current input overvoltage protection circuit, including: exchange isolation detection unit, in order to receive power supply voltage signal also
Being exported after power supply voltage signal changes into low voltage signal, described low-voltage includes the first low voltage signal and second low
Voltage signal；Absolute value amplifying unit, connects described exchange isolation detection unit and receives described low voltage signal, for basis
Voltage difference between the first low voltage signal and the second low voltage signal that are exported in low voltage signal is come optionally to institute
State the voltage difference between the first low voltage signal and the second low voltage signal be amplified and export: if described first low-voltage letter
Number more than the second low voltage signal, the most described absolute value amplifying unit is to described first low voltage signal and the second low voltage signal
Between voltage difference be amplified after give output voltage difference and amplify signal, if or described first low voltage signal is less than second
Low voltage signal, the most described absolute value amplifying unit is to the voltage between described first low voltage signal and the second low voltage signal
Difference gives output voltage difference and amplifies signal after being amplified；Crest voltage sampling unit, connects described absolute value amplifying unit, uses
To receive described voltage difference amplification signal and described voltage difference amplification signal made crest voltage collection to obtain described voltage difference
Amplify the crest voltage of signal；Overvoltage return difference unit, is connected to described crest voltage sampling unit and provides a predeterminated voltage, uses
In receiving described crest voltage and described crest voltage being compared with described predeterminated voltage, and then export according to comparative result
High or low level signal.
In the alternating-current input overvoltage protection circuit that the present invention provides, described absolute value amplifying unit is to described first low electricity
Between pressure signal and the second low voltage signal, voltage difference is amplified particularly as follows: by described first low voltage signal and the second low electricity
Pressure signal is connected in two amplifier elements on the contrary, utilizes said two amplifier element low to the first low voltage signal and second
Between voltage signal, voltage difference is amplified output.
In the alternating-current input overvoltage protection circuit that the present invention provides, also include AC input cell, be connected to civil power electricity
Source exchanges isolation detection unit with described, in order to described exchange isolation detection unit will be flowed to after described mains supply current limliting,
Wherein, described AC input cell is made up of a current-limiting resistance R1, and described resistance R1 is series at arbitrary electricity of described mains supply
In pressure side.
In the alternating-current input overvoltage protection circuit that the present invention provides, described exchange isolation detection unit is by resistance R2, electricity
Resistance R4, resistance R5 and voltage transformer composition, wherein, the input of described voltage transformer connects described AC input cell
Or mains voltage, the outfan of described voltage transformer is in parallel with described resistance R2 two ends, the first of described resistance R4
Ground connection after the first end connection of end and resistance R5, second end of described resistance R4 and the first end connection of described resistance R2, resistance
Second end of R5 and second end of described resistance R2 connect.
In the alternating-current input overvoltage protection circuit that the present invention provides, described absolute value amplifying unit is by resistance R6, resistance
R7, resistance R8, resistance R10, resistance R11, resistance R12, resistance R13, resistance R14, electric capacity C1, diode D1A, diode D1B,
Diode D2A, diode D2B, and operational amplifier U1A and operational amplifier U1B composition, wherein, the of described resistance R6
One end connects the first end and the positive input terminal of described operational amplifier U1A, second end of described resistance R11 of described resistance R11
Ground connection, first end of described resistance R7 connects negative input end and first end of described resistance R12 of described operational amplifier U1A,
First end of described resistance R8 connects positive input terminal and first end of resistance R13, the described resistance R8 of described operational amplifier U1B
The second end connect second end of second end of described resistance R7 and second end of described resistance R8 and described resistance R7 and connect simultaneously
Meet second end of resistance R5 in described exchange isolation detection unit, the second end ground connection of described resistance R13, described resistance R10
The first end connect second end of second end of described resistance R6 and first end of described resistance R10 and described resistance R6 and connect simultaneously
Connecing second end of resistance R4 in described exchange isolation detection unit, second end of described resistance R10 connects described operation amplifier
The negative input end of device U1B and first end of described resistance R14, the outfan of described operational amplifier U1A connects described diode
D1A and the positive pole of diode D1B, the outfan of described operational amplifier U1B connects described diode D2A's and diode D2B
Positive pole, second end of described resistance R12 and second end of described resistance R14 respectively with the negative pole of described diode D1A and described
The negative pole of diode D2B connects, and the negative pole of described diode D2A and the negative pole of diode D1B connect, the first of described electric capacity C1
End connects the positive pole of described operational amplifier U1A working power, the second end ground connection of described electric capacity C1.
In the alternating-current input overvoltage protection circuit that the present invention provides, described crest voltage sampling unit is by resistance R15 electricity
Holding R3 and resistance R16 composition, wherein, described resistance R15 the first end connects first end of described electric capacity C3 and described resistance R16
First end, second end of described resistance R15 connects the negative pole of described diode D2A negative pole/diode D1B, described electric capacity C3's
Second end be connected with described resistance R16 after simultaneously ground connection.
The present invention provide alternating-current input overvoltage protection circuit in, described overvoltage return difference unit by resistance R3, resistance R9,
Resistance R17, resistance R18, comparator U2, electric capacity C2 and stabilivolt Z1, wherein, first termination one of described resistance R9 presets electricity
Pressure, first end of described resistance R17 connects first end of the described resistance R15 in described crest voltage sampling unit, described electricity
Second end of resistance R9 and second end of described resistance R17 are connected with positive input terminal and the negative input end of described comparator U2 respectively,
Described comparator U2 outfan connects first end of described resistance R3, and second end of described resistance R3 connects described stabilivolt Z1's
Positive pole and first end of described resistance R18, second end of described resistance R18 connects second end of described resistance R9, described voltage stabilizing
The minus earth of pipe Z1.
Techniques described above scheme, the alternating-current input overvoltage protection circuit structure letter that the hinge structure present invention provides
Single, detection speed is fast, and circuit is reliable；And have on the over-voltage protecting function when quiescent imput voltage and any input voltage
The dynamic over-voltage defencive function of the process of liter, it addition, the setting of return difference resistance R18, it is to avoid crossing the output signal near pressure point
Vibrate back and forth, meanwhile, the setting of discharge resistance (resistance R16), when input voltage is less than setting value, can the most automatically cancel
Voltage protecting signal.
Accompanying drawing explanation
Fig. 1 is shown as the circuit theory schematic diagram of alternating-current input overvoltage protection circuit of the present invention.
Fig. 2 is shown as alternating-current input overvoltage protection circuit of the present invention and exchanges isolation detection unit in one embodiment
Circuit structure diagram.
Fig. 3 is shown as the electricity of alternating-current input overvoltage protection circuit of the present invention absolute value amplifying unit in one embodiment
Line structure figure.
Fig. 4 is shown as alternating-current input overvoltage protection circuit of the present invention crest voltage sampling unit in one embodiment
Circuit structure diagram.
Fig. 5 is shown as the circuit of alternating-current input overvoltage protection circuit overvoltage return difference in one embodiment unit of the present invention
Structure chart.
Fig. 6 is shown as the circuit of alternating-current input overvoltage protection circuit of the present invention AC input cell in one embodiment
Structure chart.
Fig. 7 is shown as alternating-current input overvoltage protection circuit of the present invention integrated circuit structure chart in one embodiment.
Drawing reference numeral explanation
1 power supply
2 alternating-current input overvoltage protection circuit
20 AC input cells
21 exchange isolation detection unit
211 first low voltage signals
212 second low voltage signals
22 absolute value amplifying units
23 crest voltage sampling units
231 discharge resistances
24 overvoltage return difference unit
241 resistance R9
242 resistance R18
243 stabilivolt Z1
3 level signals
Detailed description of the invention
Below by way of specific instantiation, embodiments of the present invention being described, those skilled in the art can be by this specification
Disclosed content understands other advantages and effect of the present invention easily.The present invention can also be by the most different concrete realities
The mode of executing is carried out or applies, the every details in this specification can also based on different viewpoints and application, without departing from
Various modification or change is carried out under the spirit of the present invention.It should be noted that, in the case of not conflicting, following example and enforcement
Feature in example can be mutually combined.
Refer to Fig. 1 to Fig. 7, it should be noted that the diagram provided in following example illustrates the most in a schematic way
The basic conception of the present invention, the most graphic in package count time only display with relevant assembly in the present invention rather than is implemented according to reality
Mesh, shape and size are drawn, and during its actual enforcement, the kenel of each assembly, quantity and ratio can be a kind of random change, and its
Assembly layout kenel is likely to increasingly complex.
Exchange input overvoltage protection is to power supply important protection, when input voltage is beyond the trouble free service electricity of power supply
During pressure, this circuit operation, it is ensured that power supply is not damaged by.Current protection circuit, owing to lacking the setting of return difference, the most protected
Circuit perseveration, meanwhile, AC-input voltage recover normal after, circuit can not automatic recovery of power supply timely, affect power supply
Timely power supply.The present invention is by adding overvoltage return difference unit 24 in alternating-current input overvoltage protection circuit 2 so that circuit is not
Action repeatedly can occur because of voltage pulsation, it is ensured that the reliability service of power supply, details are as follows for its concrete scheme.
See Fig. 1, it is shown that the circuit theory schematic diagram of alternating-current input overvoltage protection circuit of the present invention, from the point of view of figure, this
A kind of alternating-current input overvoltage protection circuit 2 of bright offer, including exchange isolation detection unit 21, absolute value amplifying unit 22, peak value
Voltage sampling unit 23 and overvoltage return difference unit 24, wherein, described exchange isolation detection unit 21 is in order to receive power supply 1 electricity
Being exported after pressing signal and power supply 1 voltage signal being changed into low voltage signal, described low-voltage is by the first low voltage signal
211 and second low voltage signal 212 form；Described absolute value amplifying unit 22 connects described exchange isolation detection unit 21 and connects
Receive described low voltage signal, for believing according to the first low voltage signal 211 exported in low voltage signal and the second low-voltage
Voltage difference between numbers 212 is come optionally to the electricity between described first low voltage signal 211 and the second low voltage signal 212
Pressure reduction is amplified and exports: if described first low voltage signal 211 is more than the second low voltage signal 212, the most described absolute value
Amplifying unit 22 gives defeated after being amplified the voltage difference between described first low voltage signal and the second low voltage signal 212
Go out voltage difference and amplify signal, if or described first low voltage signal is less than the second low voltage signal 212, and the most described absolute value is put
Big unit 22 to described voltage difference between described first low voltage signal and the second low voltage signal 212 is amplified after give
Signal is amplified with output voltage difference；Crest voltage sampling unit 23, connects described absolute value amplifying unit 22, described in order to receive
Voltage difference is amplified signal and described voltage difference amplification signal is made crest voltage collection to obtain described voltage difference amplification signal
Crest voltage；Described overvoltage return difference unit 24 is connected to described crest voltage sampling unit 23 and provides a predeterminated voltage, is used for
Receive described crest voltage and described crest voltage is compared with described predeterminated voltage, and then according to comparative result output height
Or low level signal 3.Wherein, described first low voltage signal 211 and the second low-voltage are believed by described absolute value amplifying unit 22
Between numbers 212, voltage difference is amplified particularly as follows: described first low voltage signal 211 and the second low voltage signal 212 are made phase
Counter it is connected in two amplifier elements, utilizes said two amplifier element that the first low voltage signal 211 and the second low-voltage are believed
Between numbers 212, voltage difference is amplified output.
In order to principle and the detailed technology scheme of the present invention are better understood, described exchange will be provided here to input
One physical circuit figure of voltage protection circuit 2, is illustrated technical scheme.
Specifically, Fig. 2 is seen, it is shown that alternating-current input overvoltage protection circuit of the present invention exchanges isolation in one embodiment
The circuit structure diagram of detector unit, in the alternating-current input overvoltage protection circuit 2 that the present invention provides, described exchange isolation detection list
Unit 21 is made up of resistance R2, resistance R4, resistance R5 and voltage transformer, and wherein, the input of described voltage transformer connects
Described AC input cell or mains voltage, the outfan of described voltage transformer is in parallel with described resistance R2 two ends,
First end of first end of described resistance R4 and resistance R5 connect after ground connection, second end of described resistance R4 and described resistance R2's
First end connects, and second end of resistance R5 and second end of described resistance R2 connect.
Specifically, Fig. 3 is seen, it is shown that alternating-current input overvoltage protection circuit of the present invention absolute value in one embodiment is put
The circuit structure diagram of big unit 22, in the alternating-current input overvoltage protection circuit 2 that the present invention provides, described absolute value amplifying unit
22 by resistance R6, resistance R7, resistance R8, resistance R10, resistance R11, resistance R12, resistance R13, resistance R14, electric capacity C1, two poles
Pipe D1A, diode D1B, diode D2A, diode D2B, and operational amplifier U1A and operational amplifier U1B composition, its
In, first end of described resistance R6 connects the first end and the positive input terminal of described operational amplifier U1A, the institute of described resistance R11
Stating the second end ground connection of resistance R11, first end of described resistance R7 connects the negative input end of described operational amplifier U1A and described
First end of resistance R12, first end of described resistance R8 connects the positive input terminal of described operational amplifier U1B and resistance R13
First end, second end of the second end described resistance R7 of connection of described resistance R8 and second end of described resistance R8 and described resistance
Second end of R7 is simultaneously connected with second end of the resistance R5 in described exchange isolation detection unit 21, the second of described resistance R13
End ground connection, second end of the first end described resistance R6 of connection of described resistance R10 and first end of described resistance R10 and described electricity
Second end of resistance R6 is simultaneously connected with second end of the resistance R4 in described exchange isolation detection unit 21, the of described resistance R10
Two ends connect negative input end and first end of described resistance R14 of described operational amplifier U1B, described operational amplifier U1A's
Outfan connects described diode D1A and the positive pole of diode D1B, and the outfan of described operational amplifier U1B connects described two
Pole pipe D2A and the positive pole of diode D2B, second end of described resistance R12 and second end of described resistance R14 are respectively with described two
The negative pole of pole pipe D1A and the negative pole of described diode D2B connect, and the negative pole of described diode D2A and the negative pole of diode D1B are even
Connecing, first end of described electric capacity C1 connects the positive pole of described operational amplifier U1A working power, second termination of described electric capacity C1
Ground.
Specifically, Fig. 4 is seen, it is shown that alternating-current input overvoltage protection circuit of the present invention crest voltage in one embodiment
The circuit structure diagram of sampling unit, in the alternating-current input overvoltage protection circuit 2 that the present invention provides, the sampling of described crest voltage is single
Unit 23 is made up of resistance R15 electric capacity R3 and resistance R16, and wherein, described resistance R15 the first end connects first end of described electric capacity C3
With first end of described resistance R16, second end of described resistance R15 connects the negative of described diode D2A negative pole/diode D1B
Pole, second end of described electric capacity C3 be connected with described resistance R16 after simultaneously ground connection.
Specifically, Fig. 5 is seen, it is shown that alternating-current input overvoltage protection circuit overvoltage return difference in one embodiment of the present invention
The circuit structure diagram of unit, in the alternating-current input overvoltage protection circuit 2 that the present invention provides, described overvoltage return difference unit 24 is by electricity
Resistance R3, resistance R9 241, resistance R17, resistance R18 242, comparator U2, electric capacity C2 and stabilivolt Z1 243, wherein, described
First termination one predeterminated voltage of resistance R9 241, first end of described resistance R17 connects described crest voltage sampling unit 23
In first end of described resistance R15, second end of described resistance R9 241 and second end of described resistance R17 are respectively with described
The positive input terminal of comparator U2 and negative input end connect, and described comparator U2 outfan connects first end of described resistance R3, institute
The second end stating resistance R3 connects positive pole and first end of described resistance R18 242, the described resistance of described stabilivolt Z1 243
Second end of R18 242 connects second end of described resistance R9 241, the minus earth of described stabilivolt Z1 243.
It addition, the above alternating-current input overvoltage protection circuit 2 can also include AC input cell 20, see Fig. 6, show
The circuit structure diagram of alternating-current input overvoltage protection circuit of the present invention AC input cell in one embodiment, described friendship are gone out
Stream input block 20 is connected to mains supply 1 and exchanges isolation detection unit 21 with described, in order to by after described mains supply 1 current limliting
Flowing to described exchange isolation detection unit 21, wherein, described AC input cell 20 is made up of a current-limiting resistance R1, described electricity
Resistance R1 is series on any voltage end of described mains supply 1.
Further, so that those skilled in the art is better understood when the above exchange input overvoltage protection
Circuit 2, the angle from described circuit operation logic is illustrated by the most again.
See Fig. 7, it is shown that alternating-current input overvoltage protection circuit of the present invention integrated circuit structure in one embodiment
Figure, wherein, in the drawings using voltage U1 on VJC1 line as the first low-voltage, and using voltage U2 on VCJ2 line as the second low electricity
Pressure, the operation principle of the present invention is as follows: AC-input voltage by after resistance R1 current limliting by exchange isolation detection unit 21 electricity
Pressure transformer PT1 passes the signal to the other end, resistance R2 electric current is changed into low voltage signal；At absolute value amplifying unit
In 22, by accessing from the voltage U1 being positioned on VJC1 line in exchange isolation detection unit 21 and the electricity being positioned on VCJ2 line
Pressure U2, if on VJC1 line voltage U1 more than voltage U2, operational amplifier U1A on VCJ2 line to the first low voltage signal 211 He
The voltage difference of the second low voltage signal 212 is amplified, and operational amplifier U1A is just output as, and double diode D1 turns on, and will amplify
After signal pass to peak value sampling unit, operational amplifier U1B is to the first low voltage signal 211 and the second low voltage signal
The voltage difference of 212 is amplified, and operational amplifier U1B is output as bearing, and double diode D2 ends；If voltage U1 is less than on VJC1 line
The voltage difference of the first low voltage signal 211 and the second low voltage signal 212 is entered by voltage U2 on VCJ2 line, operational amplifier U1A
Row amplifies, and U1A is output as bearing, and double diode D1 ends, and operational amplifier U1B is to the first low voltage signal 211 and the second low electricity
The voltage difference of pressure signal 212 is amplified, and operational amplifier U1B is just output as, and double diode D2 turns on, and obtains after amplifying
Voltage difference is amplified signal and is passed to peak value sampling unit；In crest voltage sampling unit 23, amplified voltage difference is amplified
Signal by after resistance R15 current limliting to electric capacity C3 and resistance R16 discharge and recharge, flow to overvoltage return difference unit 24.Now, as comparator U2
The voltage of inverting input V-exceed that comparator U2 normal phase input end presets high voltage V+ time, the outfan of comparator U2
Output low level；When the low voltage that the voltage of the inverting input V-of comparator U2 is preset less than comparator U2 normal phase input end
During V+, the outfan output high level of comparator U2；The high voltage V+ that the normal phase input end of comparator U2 is preset is referred to as wealthy family
Voltage limit, the low voltage V+ that the normal phase input end of comparator U2 is preset is referred to as low threshold voltage, and both differences are overvoltage return difference,
Return difference value is determined by resistance R9 241, resistance R18 242 and stabilivolt Z1 243；After the setting of R16, beneficially electric voltage over press,
During dropping to normal value, detection voltage is allowed to follow change in time.
For simpler ground, namely the AC input cell 20 turns that described alternating voltage isolation detection unit will receive
Change low-voltage into and pass to absolute value amplifying unit 22；Low voltage signal is carried out at voltage difference amplification by absolute value amplifying unit 22
After reason, output voltage difference amplifies signal to peak value sampling unit；It is defeated that described voltage difference amplification signal is taken peak value by peak value sampling unit
Go out to overvoltage return difference unit 24；Crest voltage is compared by overvoltage return difference unit 24 with predeterminated voltage, and according to comparative result
Export high or low level signal (such as, if crest voltage is more than predeterminated voltage output low level, if crest voltage is less than
Predeterminated voltage output high level).Generally, described alternating-current input overvoltage protection circuit 2 simple in construction that the present invention provides, inspection
Degree of testing the speed is fast, and circuit is reliable, has the over-voltage protecting function when quiescent imput voltage and any input voltage uphill process
Dynamic over-voltage defencive function, wherein, the setting of return difference resistance R18, it is to avoid vibrate back and forth crossing the output signal near pressure point,
Meanwhile, the setting of discharge resistance 231 (i.e. resistance R16), when input voltage is less than setting value, can the most automatically cancel overvoltage
Protection signal.
In sum, the present invention, by adding overvoltage return difference unit 24 in alternating-current input overvoltage protection circuit 2, makes guarantor
There is not action repeatedly because of voltage pulsation in protection circuit, it is ensured that the reliability service of power supply.So, the present invention effectively overcomes
Various shortcoming of the prior art and have high industrial utilization.
The principle of above-described embodiment only illustrative present invention and effect thereof, not for limiting the present invention.Any ripe
Above-described embodiment all can be modified under the spirit and the scope of the present invention or change by the personage knowing this technology.Cause
This, have usually intellectual such as complete with institute under technological thought without departing from disclosed spirit in art
All equivalences become are modified or change, and must be contained by the claim of the present invention.
Claims (7)
1. an alternating-current input overvoltage protection circuit, it is characterised in that at least include:
Exchange isolation detection unit, in order to give after receiving power supply voltage signal and power supply voltage signal being changed into low voltage signal
With output, described low voltage signal includes the first low voltage signal and the second low voltage signal；
Absolute value amplifying unit, connects described exchange isolation detection unit and receives described low voltage signal, for according to low electricity
In pressure signal, voltage difference between the first low voltage signal and the second low voltage signal that are exported is come optionally to described the
Voltage difference between one low voltage signal and the second low voltage signal is amplified and exports:
If described first low voltage signal is more than the second low voltage signal, the most described absolute value amplifying unit is to described first low electricity
Voltage difference between pressure signal and the second low voltage signal gives output voltage difference and amplifies signal after being amplified, or
If described first low voltage signal is less than the second low voltage signal, the most described absolute value amplifying unit is to described first low electricity
Voltage difference between pressure signal and the second low voltage signal gives output voltage difference and amplifies signal after being amplified；
Crest voltage sampling unit, connects described absolute value amplifying unit, amplifies signal and to institute in order to receive described voltage difference
State voltage difference amplification signal and make crest voltage collection to obtain the crest voltage of described voltage difference amplification signal；
Overvoltage return difference unit, is connected to described crest voltage sampling unit and provides a predeterminated voltage, is used for receiving described peak value
Described crest voltage is also compared by voltage with described predeterminated voltage, and then exports high or low level letter according to comparative result
Number；
Described absolute value amplifying unit by resistance R6, resistance R7, resistance R8, resistance R10, resistance R11, resistance R12, resistance R13,
Resistance R14, electric capacity C1, diode D1A, diode D1B, diode D2A, diode D2B, and operational amplifier U1A and fortune
Calculating amplifier U1B composition, wherein, first end of described resistance R6 connects first end of described resistance R11 and described operation amplifier
The positive input terminal of device U1A, the second end ground connection of described resistance R11, first end of described resistance R7 connects described operational amplifier
The negative input end of U1A and first end of described resistance R12, first end of described resistance R8 connects described operational amplifier U1B's
Positive input terminal and first end of resistance R13, second end of described resistance R8 connects second end of described resistance R7 and described resistance
Second end of R8 is simultaneously connected with second end of the described resistance R5 exchanged in isolation detection unit with second end of described resistance R7,
The second end ground connection of described resistance R13, first end of described resistance R10 connects second end of described resistance R6 and described resistance
First end of R10 is simultaneously connected with the second of the described resistance R4 exchanged in isolation detection unit with second end of described resistance R6
End, second end of described resistance R10 connects negative input end and first end of described resistance R14, the institute of described operational amplifier U1B
The outfan stating operational amplifier U1A connects positive pole and the positive pole of diode D1B, the described operation amplifier of described diode D1A
The outfan of device U1B connects positive pole and the positive pole of diode D2B, second end of described resistance R12 and the institute of described diode D2A
The negative pole stating diode D1A connects, and second end of described resistance R14 and the negative pole of described diode D2B connect, described diode
The negative pole of D2A and the negative pole of diode D1B connect, and first end of described electric capacity C1 connects described operational amplifier U1A work electricity
The positive pole in source, the second end ground connection of described electric capacity C1.
Alternating-current input overvoltage protection circuit the most according to claim 1, it is characterised in that also include AC input cell,
Be connected to mains supply and exchange isolation detection unit with described, in order to by flow to after described mains supply current limliting described exchange every
From detector unit.
Alternating-current input overvoltage protection circuit the most according to claim 2, it is characterised in that described AC input cell is by one
Current-limiting resistance R1 forms, and described resistance R1 is series on any voltage end of described mains supply.
Alternating-current input overvoltage protection circuit the most according to claim 1 and 2, it is characterised in that described absolute value amplifies single
Voltage difference between described first low voltage signal and the second low voltage signal is amplified particularly as follows: by described first low electricity by unit
Pressure signal and the second low voltage signal are connected in two amplifier elements on the contrary, utilize said two amplifier element low to first
Between voltage signal and the second low voltage signal, voltage difference is amplified output.
Alternating-current input overvoltage protection circuit the most according to claim 2, it is characterised in that described exchange isolation detection unit
Being made up of resistance R2, resistance R4, resistance R5 and voltage transformer, wherein, the input of described voltage transformer connects described
AC input cell or mains voltage, the outfan of described voltage transformer is in parallel with described resistance R2 two ends, described
Ground connection after first end of resistance R4 and the first end connection of resistance R5, second end of described resistance R4 and the first of described resistance R2
End connects, and second end of resistance R5 and second end of described resistance R2 connect.
Alternating-current input overvoltage protection circuit the most according to claim 1, it is characterised in that described crest voltage sampling unit
By resistance R15, electric capacity C3 and resistance R16 form, wherein, described resistance R15 the first end connect described electric capacity C3 the first end and
First end of described resistance R16, second end of described resistance R15 connects the negative pole of described diode D2A and the negative of diode D1B
Pole, second end of described electric capacity C3 be connected with described resistance R16 after and ground connection.
Alternating-current input overvoltage protection circuit the most according to claim 6, it is characterised in that described overvoltage return difference unit is by electricity
Resistance R3, resistance R9, resistance R17, resistance R18, comparator U2, electric capacity C2 and stabilivolt Z1 composition, wherein, described resistance R9's
First termination one predeterminated voltage, first end of described resistance R17 connects the described resistance R15 in described crest voltage sampling unit
The first end, second end of described resistance R9 is connected with the positive input terminal of described comparator U2, second end of described resistance R17 with
The negative input end of described comparator U2 connects, and described comparator U2 outfan connects first end of described resistance R3, described resistance
Second end of R3 connects positive pole and first end of described resistance R18 of described stabilivolt Z1, and second end of described resistance R18 connects
Second end of described resistance R9, the minus earth of described stabilivolt Z1.
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| CN105790220B (en) * | 2014-12-17 | 2018-10-23 | 国家电网公司 | A kind of half-bridge topology converter short-circuit protection circuit and method |
| 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 |
| CN108627746A (en) * | 2018-07-20 | 2018-10-09 | 哈尔滨理工大学 | Bipolar Weak Signal Measuring Device for Insulation Detection |
| CN114498551B (en) * | 2022-04-18 | 2022-07-01 | 青岛鼎信通讯股份有限公司 | An overvoltage protection method, device, equipment and medium for a single-phase electric energy meter |
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