CN105449632B - For protecting the device and method of low-voltage circuit - Google Patents
For protecting the device and method of low-voltage circuit Download PDFInfo
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- CN105449632B CN105449632B CN201410403621.4A CN201410403621A CN105449632B CN 105449632 B CN105449632 B CN 105449632B CN 201410403621 A CN201410403621 A CN 201410403621A CN 105449632 B CN105449632 B CN 105449632B
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Abstract
The disclosure provides a kind of for protecting the device and method thereof of low-voltage circuit.The equipment includes: measuring circuit, for measuring input voltage；Comparison circuit, for the measured value of input voltage to be compared with reference value；And half control type switching device, for being controlled to provide the input voltage to low-voltage circuit when measured value meets predetermined condition with reference value.Therefore, low-voltage circuit only just can be provided to when input voltage is normal DC low-voltage by simple structure, to realize the protection to low-voltage circuit.
Description
Technical field
This disclosure relates to it is a kind of for protecting the device and method of low-voltage circuit, pass through half more specifically to one kind
Control type switching device protects the device and method of low-voltage circuit.
Background technique
Product in use, probably due to the carelessness or wiring error of user and would be limited in DC low-voltage range
In the product misconnection to AC network inside used, so that product is damaged.Then, user has to carry out impaired product
The product for repairing and more renewing, this not only adds the costs of user, and increase the repair rate of goods producer.
Currently, it can be carried out precise voltage protection there are some, high-voltage alternating (or direct current) electricity prevented to be input into low pressure production
Product are so that damage the design of product, but structures of these designs are more complicated.
Can be under power grid alternating current (or high voltage direct current) and DC low-voltage electricity the two in addition, although there are some products
It can operate, but such product cost is higher.
Accordingly, it would be desirable to which a kind of structure for the case where providing misconnection AC network for user is simply to protection low pressure
The device and method of circuit.
Summary of the invention
The structure that the embodiment of the present disclosure provides a kind of the case where misconnection AC network for user is simply to protect low
The device and method of volt circuit.
According to one aspect of the disclosure, a kind of equipment for protecting low-voltage circuit is provided, comprising: measuring circuit is used
In measurement input voltage；Comparison circuit, for the measured value of input voltage to be compared with reference value；And half control type switch
Device, for being controlled to provide the input voltage to low tension when measured value meets predetermined condition with reference value
Road.
Optionally, the comparison result of comparison circuit is output to the gate pole of half control type switching device, and half control type switchs
The anode and cathode of device is connected voltage and provides in path.
Optionally, measuring circuit includes bleeder circuit, and the measured value of input voltage is input voltage via the partial pressure
Circuit is applied to the voltage of comparison circuit.
Optionally, it includes: that the measured value is greater than or equal to reference value that measured value and reference value, which meet predetermined condition,；Or
The measured value is less than or equal to reference value.
Optionally, the bleeder circuit includes resistance and capacitor.
Optionally, the bleeder circuit includes resistance, and the equipment further includes the diode connecting with bleeder circuit.
Optionally, the equipment further comprises: holding circuit, for remaining applied to half control when input voltage interrupts
The signal of the gate pole of type switching device.
Optionally, the holding circuit includes resistance and capacitor.
Optionally, comparison circuit includes switching transistor, and the reference value is the threshold voltage of switching transistor.
According to another aspect of the disclosure, a kind of method for protecting low-voltage circuit is provided, comprising: measurement input electricity
Pressure；The measured value of input voltage is compared with reference value；And when measured value meets predetermined condition with reference value, pass through
Half control type switching device is controlled to provide the input voltage to low-voltage circuit.
Optionally, measurement input voltage includes the voltage for measuring input voltage and being applied to comparison circuit via bleeder circuit,
As measured value.
Optionally, the bleeder circuit includes resistance and capacitor.
Optionally, the bleeder circuit includes resistance, and the method also includes: input electricity is acquired by diode
The positive polarity portion of pressure.
Optionally, the method further includes: when input voltage interrupt when remain applied to half control type switching device
The signal of gate pole.
Optionally, the signal of the gate pole of half control type switching device is remained applied to by resistance and capacitor.
Optionally, comparison circuit includes switching transistor, and the reference value is the threshold voltage of switching transistor.
Therefore, according to the embodiment of the present disclosure, using half control type switching device, when input voltage is normal DC voltage,
For rear class low-voltage circuit export normal DC voltage, and when input voltage be too high voltages when, block the input voltage without
Too high voltages are introduced into rear class.Thus can be only when input voltage is normal DC low-voltage just by it by simple structure
Low-voltage circuit is provided, to realize the protection to low-voltage circuit.
Detailed description of the invention
Pass through the detailed description below by attached drawing, it will the present invention is more easily to understand, wherein identical label is specified
Mutually isostructural unit, and wherein:
Fig. 1 is the schematic block diagram for showing the equipment for protecting low-voltage circuit according to the embodiment of the present disclosure；
Fig. 2 (a) and Fig. 2 (b) is to show to be shown according to the specific of the equipment for protecting low-voltage circuit of the embodiment of the present disclosure
The simplified schematic circuit diagram of example；
Fig. 3 is the signal for showing the equipment for protecting low-voltage circuit of the first embodiment according to the embodiment of the present disclosure
Property circuit diagram；
Fig. 4 is the signal for showing the equipment for protecting low-voltage circuit of the second embodiment according to the embodiment of the present disclosure
Property circuit diagram；With
Fig. 5 shows the schematic flow chart of the method for protecting low-voltage circuit according to the embodiment of the present disclosure.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are some of the embodiments of the present invention, instead of all the embodiments.Based on this hair
Embodiment in bright, every other implementation obtained by those of ordinary skill in the art without making creative efforts
Example, shall fall within the protection scope of the present invention.
It should be understood that when one element of title another element " on " when, can be on other elements
Or may exist insertion element therebetween.On the contrary, when claim an element " direct " another element " on " when, be not present any
Insertion element.As used herein, term "and/or" includes that one or more correlations list any of item and all combination.
It should be appreciated that when an element referred to as " connects " or when " coupled " to another element, can be directly connected to or coupling
It is connected to another element or there may be intermediary elements.On the contrary, working as, an element referred to as " is directly connected to " or " directly coupling " is arrived
When another element, intermediary element is not present.It should be solved in a similar manner for describing other words of the relationship between element
Release (for example, " between " relative to " directly between ", " adjacent " relative to " direct neighbor " etc.).
It should be understood that although can be used herein term first, second, third, etc. describes various elements, component, area
Domain, layer and/or part, but these elements, component, regions, layers, and/or portions do not should be these terms and are limited.These
Term is used only for an element, component, regions, layers, and/or portions and another element, component, region, layer and/or portion
Split-phase is distinguished.Thus, first element discussed below, component, regions, layers, and/or portions can be regarded as second element, group
Part, regions, layers, and/or portions, without departing from the teachings of the present invention.
Term used herein is used for the purpose of for the purpose of describing particular embodiments, and is not intended to limit the present invention.
As used herein, singular " one ", "one" and "the" are intended to also include plural form, unless clearly indicated by the context
It is really not so.It should also be appreciated that when used in this manual, term " includes " and/or " including ... " or "comprising"
And/or " including ... " specified illustrated feature, region, integer, step, operation, the presence of element and/or component, but
Be do not preclude the presence or addition of other one or more features, region, integer, step, operation, element and/or component and/or its
Group.
Fig. 1 is the schematic block diagram for showing the equipment 100 for protecting low-voltage circuit according to the embodiment of the present disclosure.
As shown in fig. 1, the equipment 100 for protecting low-voltage circuit includes measuring circuit 101, comparison circuit 102 and half
Control type switching device 103.
Measuring circuit 101 is for measuring input voltage.Comparison circuit 102 is used for the measured value and reference value of input voltage
It is compared.Half control type switching device 103 is used for when measured value and reference value meet predetermined condition, is controlled with will be described
Input voltage is provided to low-voltage circuit.
Therefore, according to the embodiment of the present disclosure, using half control type switching device, when input voltage is normal DC voltage,
Equipment 100 is the low-voltage circuit output normal DC voltage of rear class, and when input voltage is too high voltages, equipment 100 blocks
The input voltage is without introducing rear class for too high voltages.To which equipment 100 can only be when input voltage by simple structure
It is just provided to low-voltage circuit when normal DC low pressure, to realize the protection to low-voltage circuit.
In one example, half control type switching device 103 can be thyristor.
In a specific example, the comparison result of comparison circuit 102 is output to the door of half control type switching device 103
Pole, and the anode and cathode of half control type switching device 103 is connected voltage and provides in path.Comparison result can directly or
Person is output to the gate pole of half control type switching device 103 by driving circuit.Here, voltage provides path and refers to input voltage
The path of low-voltage circuit is provided to via half control type switching device 103, such as shown in fig. 1, it is defeated that voltage, which provides path,
Enter voltage → 103 → output voltage of half control type switching device → low-voltage circuit path.
In addition, by using half control type switching device 103 (typical device such as thyristor), it is ensured that opened in the half control type
As long as having electric current to flow through equipment 100 after closing 103 normally of device would not turn off, this greatly reduces equipment 100 and is accidentally closed
Disconnected probability improves the reliability of operation.
In addition, even if when the terminals of input voltage are reversely connected and cause the polarity of input voltage opposite, because using
Half control type switching device 103, so can be prevented using the reversed cut-off characteristics of half control type switching device by the defeated of reversed polarity
Enter voltage and be transmitted to rear class, to further the device in late-class circuit be protected not to be damaged.
Fig. 2 (a) and Fig. 2 (b) are shown according to the specific of the equipment 100 for protecting low-voltage circuit of the embodiment of the present disclosure
Exemplary simplified schematic circuit diagram, wherein Fig. 2 (a) shows half control type switching device 103 and is connected voltage offer path
Main track on situation, and Fig. 2 (b) show half control type switching device 103 be connected voltage provide path negative wire on
Situation.
It should be appreciated that Fig. 2 (a) and Fig. 2 (b) are not practical circuit diagram, but purpose for clarity and conciseness is only
It illustrates only component necessary to explaining the embodiment of the present disclosure and other assemblies as known in the art is omitted to avoid mould
The theme of the disclosure is pasted, those skilled in the art, which can according to need, adds other required components.For example, in Fig. 2 (a) and Fig. 2
(b) in, the comparison result for showing Q1 is supplied directly to half control type switching device 103 to control its gate pole, but is actually answering
In, it is clear that there may also be driving circuits between them, rather than Q1 is directly connected with half control type switching device 103.It changes
Sentence is talked about,, in practice can also be with even being shown as the part of conducting wire in the schematic diagram shown in Fig. 2 (a) and Fig. 2 (b)
For components such as resistance, switching device, capacitors.
As shown in Fig. 2 (a), measuring circuit 101 may further include bleeder circuit 1011.In this case, defeated
Enter measured value of the voltage as input voltage that voltage is applied to comparison circuit via the bleeder circuit.
In Fig. 2 (a), comparison circuit 102 may include a switching transistor Q1, and input voltage is via partial pressure electricity
Road 1011 is applied to the voltage V of the base stage of switching transistor Q1BAs the measured value of input voltage and the threshold voltage V of Q1th(base
Pole threshold voltage) it is compared.
Shown in Fig. 2 (a), when the direct current that input voltage is normal DC voltage, such as 12-48V
When pressure, the voltage V of the base stage of switching transistor Q1 is applied to via bleeder circuit 1011BMore than or equal to Vth, so that Q1 is connected,
So that the gate pole of half control type switching device 103 obtains trigger signal and is connected, normal direct voltage output is arrived into rear class
Low-voltage circuit.
Situation in Fig. 2 (b) is similar with situation shown in Fig. 2 (a), and different is only half control type switching device
103, which are located at voltage, is provided in the negative wire in path.In this case, when input voltage is normal DC voltage, such as 12-
When the DC voltage of 48V, the voltage V of the base stage of switching transistor Q1 is applied to via bleeder circuit 1011BLess than or equal to Vth,
To which Q1 ends, so that the gate pole of half control type switching device 103 obtains trigger signal by input voltage and is connected, it will be normal
Direct voltage output to rear class low-voltage circuit.
Although those skilled in the art should be bright in addition, comparison circuit 102 is shown as a switching transistor Q1
It is white, other assemblies can also be added or realize comparison circuit 102 using other simulations or logical device, as long as its energy
Realize the function of comparison circuit 102 as described above.
Hereafter, it further describes with reference to the accompanying drawings according to the embodiment of the present disclosure for protecting the equipment 100 of low-voltage circuit
Specific embodiment.
Fig. 3 is the equipment 300 for being used to protect low-voltage circuit for showing the first embodiment according to the embodiment of the present disclosure
Schematic circuit.
As shown in Figure 3, equipment 300 includes serving as the bleeder circuit 3011, comparison circuit 302 and half control of measuring circuit
Type switching device 303.Bleeder circuit 3011 includes resistance R1 and capacitor C1, and comparison circuit 302 includes switching transistor Q1
And resistance R2 and R3；Half control type switching device 303 is connected voltage and provides on the main track in path, and anode is connected to input
Voltage end, cathode is connected to output voltage terminal, and its gate pole is connected to switching transistor Q1.
In the equipment 300 according to the first embodiment, the capacitor that includes in bleeder circuit 3011 with input voltage
The voltage value got on C1 is sampled as characteristic quantity.Input voltage can be divided on bleeder circuit 3011, wherein
The ratio between voltage value and input voltage value for getting on capacitor C1 are impedance gain.
When inputting normal DC voltage, the capacitive reactance X of capacitor C1c=1/2 π fc is infinitely great, and impedance gain is very big, to protect
Sufficiently high voltage magnitude is obtained the Q1 as comparison circuit 302 is connected on card capacitor C1, and the triggering end of thyristor 303 is (i.e.
Gate pole) it obtains trigger signal and is connected, and then input voltage is provided to the low-voltage circuit of rear class.Here, f indicates input voltage
Frequency, and c indicate capacitor C1 capacitance.
However, when input AC high voltage, the capacitive reactance of capacitor C1 becomes smaller value, impedance gain very little, thus
Keep the voltage magnitude on capacitor C1 very low, this guarantee does not turn on the Q1 as comparison circuit, so that the triggering of thyristor 303
It holds Triggerless and is held off, and then ensure that high AC voltage will not be passed to the low-voltage circuit of rear class.
In addition, as described above, the triggering end (gate pole) because of thyristor 303 could be switched on when being only applied positive voltage,
So even if when the normal DC polarity of voltage of input is opposite, because the triggering end of thyristor 303 has been applied back-pressure, therefore its
It is held off without providing opposite polarity input voltage to rear class, this prevent the poles of the normal DC voltage when input
Property by it is reversed when late-class circuit in component be damaged.
In the case shown in fig. 3, according to aforementioned it is found that when normal 12-48V DC voltage passes through bleeder circuit
3011 and when being applied to the voltage in Q1 base stage and being greater than or equal to the threshold voltage of Q1, Q1 conducting is led to triggering thyristor 303
It is logical；And when the 100-240V ac high-voltage introduced by mis-wired is applied to the electricity in Q1 base stage by bleeder circuit 3011
It forces down when the threshold voltage of Q1, Q1 cut-off, so that thyristor 303 is held off.
In the equipment 300, it is expected that when inputting 12V DC voltage, Q1 can be switched on, and as input 240V/50Hz
It can guarantee that Q1 is ended when alternating voltage.Here, the base stage threshold voltage of Q1 is about in 0.3V~0.8V or so.
When inputting 12V DC voltage, C1 is equivalent to open circuit, if considering R1:R2:R3=10:1:1, is applied to Q1
Voltage in base stage is 1V > 0.8V, this can guarantee that Q1 is switched on.When inputting 240V/50Hz alternating voltage, if considered
Impedance (i.e. capacitive reactance) X on C1cThe relationship of=1/2 π fc and R1, R2, R3 are R1:Xc: R2:R3=10:0.015:1:1 is then applied
The voltage peak being added in Q1 base stage is 0.27V < 0.3V, this ensures that Q1 will not be switched on.
In one example, R1=1M Ω, C1=2.2 μ F, R2=R3=100k Ω.It is clear that those skilled in the art
Member, which can according to need, is specifically identified as other appropriate values for the value of R1 to R6 and C1.
Therefore, it using the equipment 300 according to the first embodiment, can effectively be protected by simple circuit structure
Card: in the case where this circuit devcie is in the original state being substantially discharged, the DC voltage quilt when inputting normal DC voltage
The low-voltage circuit of rear class is provided, and prevents it from being passed to rear class when inputting power grid ac high voltage and damages low-voltage circuit
In component.In addition, the thyristor, resistance, capacitor and the switching transistor that include in the equipment 300 are cheap electronics
Device which further simplifies circuit structure and reduces costs.
In addition, as shown in Figure 3, C1 and R2 are further formed holding circuit, apply for keeping when input voltage interrupts
It is added in the signal of the gate pole of half control type switching device (thyristor) 303.Specifically, the normal DC voltage generation when input is short
When temporarily interrupting, thyristor 303 is turned off because no current flows through, and capacitor C1 is by the resistance R2 electric discharge in Q1 base stage at this time, when
Between guarantee that the base stage of Q1 has electric current to ensure that Q1 is constantly on always in constant, τ 1=R2C1, i.e. holding half control type derailing switch
The gate pole trigger signal channel of part 303 is connected always, this ensure that when input voltage is in break period < τ 1=R2C1
Between when restoring normal after section, half control type switching device 303 can also when input voltage restores normal triggering and conducting immediately.This is really
The input of direct current required by PLC (Programmable Logic Controller, programmable logic controller (PLC)) product is protected
Voltage short interruption-restorability.Those skilled in the art can be adjusted by the capacitance and the resistance value of R2 for adjusting C1
Timeconstantτ 1=RC.
In some cases, the low-voltage circuit for not only needing that ac high voltage is prevented to be passed to rear class, also needs sometimes
DC high voltage is prevented to be passed to rear class.In this case, above-mentioned equipment 300 according to first embodiment is unable to satisfy
Demand.
Fig. 4 is the equipment 400 for being used to protect low-voltage circuit for showing the second embodiment according to the embodiment of the present disclosure
Schematic circuit.
As shown in Figure 4, equipment 400 includes serving as the bleeder circuit 4011, comparison circuit 402 and half control of measuring circuit
Type switching device 403.Unlike equipment 300 shown in Fig. 3, equipment 400 includes isolated holding circuit 404, and
Bleeder circuit 4011 includes resistance r1, r2, and comparison circuit 402 includes switching transistor Q1；403 quilt of half control type switching device
Voltage is connected to provide in the negative wire in path, anode is connected to output voltage terminal, and cathode is connected to Input voltage terminal, and
Its gate pole is connected to switching transistor Q1.
In the equipment 400 according to the second embodiment, the negative polarity portion of alternating voltage is filtered out using diode D1
The positive polarity portion for dividing and acquiring alternating voltage handles its peak value, to carry out identical processing with DC high voltage.
Bleeder circuit 4011 uses resistor network, is sampled using voltage value of the input voltage on divider resistance as characteristic quantity.Electricity
Resistance network is identical for DC voltage impedance gain, and the voltage value sampled is proportional to the voltage value of input.
When inputting normal DC voltage, the voltage obtained through the resistor network sampling as bleeder circuit 4011 compares
It is low, guarantee that the Q1 as comparison circuit 402 is not turned on, to pass through Q2 for 403 triggering and conducting of thyristor.
When input AC high voltage or DC high voltage, the voltage obtained through resistor network sampling is relatively high, guarantees to make
It is switched on for the Q1 of comparison circuit 402, so that Q2 is ended, Triggerless is applied to the gate pole (triggering of thyristor 403
End), so thyristor is held off, and then ensure that ac high voltage or DC high voltage will not be passed to the low tension of rear class
Road.
In addition, ground is similar with first embodiment, when being only applied positive voltage because of the triggering end (gate pole) of thyristor 403
It could be switched on, so even if when the normal DC polarity of voltage of input is opposite, because the triggering end of thyristor 403 is applied
Back-pressure, therefore it is held off without providing opposite polarity input voltage to rear class, this prevent normal when what is inputted
The polarity of DC voltage by it is reversed when late-class circuit in component be damaged.
In addition, thyristor 403 is turned off because no current flows through when inputting normal DC voltage generation short interruption, this
When capacitor c2 by the resistance r4 electric discharge in Q2 base stage, guarantee that the base stage of Q2 has electric current always in timeconstantτ 2=r4c2
So that it is guaranteed that Q2 is connected, the gate pole trigger signal channel of thyristor 403 is connected always.This ensure that when input voltage is interrupting
When restoring normal after time < τ 2=r4c2 period, thyristor 403 can also triggering be led immediately when input voltage restores
It is logical.In addition, holding circuit 404 be other than it can play the role of holding, can also when input powers on from Time-delayed trigger,
Ensure normal timing.
In the equipment 400, it is expected that when inputting 48V DC voltage, Q1 keeps cut-off, and when input 100V/60Hz is handed over
Q1 can be switched on when galvanic electricity pressure or equivalent DC high voltage.Here, the base stage threshold voltage of Q1 about 0.3V~
0.8V or so.
When inputting 48V direct current, if considering r1:r2=170:1, be applied to voltage in Q1 base stage be 0.28V <
0.3V, this can guarantee that Q1 is ended.When inputting 100V/50Hz ac high voltage or equivalent DC high voltage, consider such as
Fruit r1:r2=170:1, the then voltage peak being applied in Q1 base stage are 0.82V > 0.8V, this can guarantee that Q1 is switched on.
Simultaneously, it is contemplated that the holding effect of holding circuit 404 and time-lag action: expected time constant, τ 3=r3c2 > >
20ms is wanted so that the state for guaranteeing in Q1 is actually determined not have any trigger signal and be applied to the timing of thyristor 403
It asks；And expected time constant, τ 2=r4c2 > > 10ms, to play the role of holding when input voltage interrupts.
In one example, r1=1M Ω, r2=5.6k Ω, r3=1M Ω, c2=1 μ F, r4=100k Ω.But it is aobvious
Right those skilled in the art, which can according to need, is specifically identified as other appropriate values for the value of r1 to r4 and c2.
Therefore, it using the equipment 400 according to the second embodiment, can effectively be protected by simple circuit structure
Card: in the case where this circuit devcie is in the original state being substantially discharged, the DC voltage quilt when inputting normal DC voltage
The low-voltage circuit of rear class is provided, and can be prevented when input AC high voltage or DC high voltage its be passed to rear class and
Damage the component in low-voltage circuit.In addition, the thyristor for including in the equipment 400, resistance, capacitor, diode and switch crystal
Pipe is cheap electronic device, which further simplifies circuit structure and is reduced costs.In addition, by utilizing holding
Circuit 404 not only ensures the short interruption of DC input voitage required by PLC product-restorability, and can be defeated
Enter and play Time-delayed trigger when powering on, guarantees normal timing.
It should be appreciated that although half control type switching device 303 is shown located on main track in the first embodiment
And half control type switching device 403 is shown located in negative wire in this second embodiment, but the embodiment of the present disclosure is not limited to
This.Obviously, those skilled in the art can be according to the duality relation of main track and negative wire, depending on needing half control type switching device
303 and 503 are connected on one in main track and negative wire.Because other than connection type is slightly different, by half control type derailing switch
Situation that part 303 is connected in negative wire and by half control type switching device 403 be connected to the situation on main track respectively with Fig. 3 and figure
Embodiment shown in 4 is similar, so the repeated description to it is omitted for simplicity here.
Here, Q1 and Q2 shown in Fig. 4 can be the device identical or different with Q1 shown in Fig. 3 and Q2, and
Although Q1 and Q2 are shown as N-type transistor or P-type transistor in figures 3-4, those skilled in the art can basis
Demand and use P-type transistor or N-type transistor or N/P type field-effect tube, even other switch elements, without departing from this
Scope of disclosure.
Fig. 5 shows the schematic flow chart of the method 500 for protecting low-voltage circuit according to the embodiment of the present disclosure.
As shown in Fig. 5, the 501 of method 500, input voltage is measured.502, by the measured value of input voltage and reference
Value is compared.503, when measured value and reference value meet predetermined condition, by half control type switching device controlled with
There is provided the input voltage to low-voltage circuit.
Therefore, according to the embodiment of the present disclosure, by utilizing half control type switching device, when input voltage is normal DC voltage
When, be that the low-voltage circuit of rear class exports normal DC voltage, and block the input voltage when input voltage is too high voltages and
Too high voltages rear class is not introduced into.To can only just will when input voltage is normal DC low-voltage by simple structure
It, which is provided, arrives low-voltage circuit, to realize the protection to low-voltage circuit.
In one example, it may include that measurement input voltage applies via bleeder circuit that input voltage is measured in 501
To the voltage of comparison circuit, as measured value.
In one example, bleeder circuit may include resistance and capacitor, bleeder circuit 3011 as shown in Figure 3.?
In this case, ac high voltage can be prevented to be passed to the low-voltage circuit of rear class.
In one example, bleeder circuit may include resistance, bleeder circuit 4011 as shown in Figure 4, and method
500 can also include: by diode before measuring input voltage come rectified input voltage.In such a case, it is possible to anti-
Only both ac high voltage and DC high voltage are passed to the low-voltage circuit of rear class.
In addition, method 500 can further include: remaining applied to half control type switching device when input voltage interrupts
Gate pole signal.For example, can realize the holding by c2 shown in C1 shown in Fig. 3 and R2 and Fig. 4 and r4
Effect.
In one example, can be by switching transistor as comparison circuit, and reference value can be switch crystalline substance
The threshold voltage of body pipe.
For embodiment of the disclosure for protecting low-voltage power supply equipment (12~48Vdc) because installation is neglected, misconnection enters alternating current
The case where powering on after net (100~240Vac), does not consider other voltage conditions, does not consider that voltage is unexpected after normally working on power yet
The case where raising.
Therefore, in the method for protecting low-voltage circuit according to the embodiment of the present disclosure, it is only necessary to by using half control
Type switching device, it is ensured that as long as having electric current to flow through equipment after the half control type switching device normally would not turn off,
This greatly reduces the probability that equipment is accidentally turned off, and improves the reliability of operation.
In addition, even if when the terminals of input voltage are reversely connected and cause the polarity of input voltage opposite, because using
Half control type switching device, so can be prevented using the reversed cut-off characteristics of half control type switching device by the input electricity of reversed polarity
Pressure is transmitted to rear class, so that the device in late-class circuit be protected not to be damaged.
Furthermore it because not considering other voltage values, does not need to do accurate voltage protection point, it is only necessary to can judge it is low pressure
DC voltage or ac grid voltage can use the threshold value of switching transistor so not needing very accurate reference value
Voltage is as reference value.
It is thus possible to effectively guarantee the DC voltage when inputting normal DC voltage by simple circuit structure
It is provided to the low-voltage circuit of rear class, and prevents it from being passed to rear class when input AC high voltage or DC high voltage and damages
Component in bad low-voltage circuit.In addition, this method is using cheap electricity such as thyristor, resistance, capacitor and switching transistors
Sub- device which further simplifies circuit structure and reduces costs.In addition, not only ensuring PLC by utilizing holding circuit
The short interruption of DC input voitage required by product-restorability, and can when input powers on from Time-delayed trigger make
With guaranteeing normal timing.
It should be noted that for clarity and conciseness, being illustrated only in Fig. 2 into Fig. 4 relevant to the embodiment of the present invention
Part, but it will be appreciated by those skilled in the art that, equipment or device shown in Fig. 2 to Fig. 4 may include other necessity
Unit.
Those of ordinary skill in the art may be aware that list described in conjunction with the examples disclosed in the embodiments of the present disclosure
Member and algorithm steps, can be realized with electronic hardware, computer software, or a combination of the two, in order to clearly demonstrate hardware
With the interchangeability of software, each exemplary composition and step are generally described according to function in the above description.This
A little functions are implemented in hardware or software actually, the specific application and design constraint depending on technical solution.Specially
Industry technical staff can use different methods to achieve the described function each specific application, but this realization is not
It is considered as beyond the scope of this invention.
It is apparent to those skilled in the art that for convenience and simplicity of description, the system of foregoing description,
The specific work process of device and unit, can refer to corresponding processes in the foregoing method embodiment, and details are not described herein.
The unit as illustrated by the separation member may or may not be physically separated, aobvious as unit
The component shown may or may not be physical unit, both can be located in one place, or may be distributed over multiple
In network unit.It can select some or all of unit therein according to the actual needs to realize the mesh of this embodiment scheme
's.
It, can also be in addition, the functional units in various embodiments of the present invention may be integrated into one processing unit
It is that each unit physically exists alone, can also be integrated in one unit with two or more units.
The above description is merely a specific embodiment, but scope of protection of the present invention is not limited thereto, any
Those familiar with the art in the technical scope disclosed by the present invention, can easily think of the change or the replacement, and should all contain
Lid is within protection scope of the present invention.Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. a kind of equipment for protecting low-voltage circuit in misconnection alternating current, comprising:
Measuring circuit, the input voltage of the alternating current-direct current for measuring input；
Comparison circuit, for the measured value of the input voltage of the alternating current-direct current of input to be compared with reference value；And
Half control type switching device, for being controlled so that the input is electric when measured value meets predetermined condition with reference value
Pressure is provided to low-voltage circuit and is not turned off as long as having electric current to flow through the equipment after the half control type switching device normally,
Wherein, measuring circuit includes bleeder circuit and the diode that connect with bleeder circuit, and the measured value of input voltage is
Input voltage is filtered out the negative polarity portion of alternating voltage using the diode and acquires friendship after dividing via the bleeder circuit
The positive polarity portion of galvanic electricity pressure and the voltage for being applied to comparison circuit, the bleeder circuit includes resistance.
2. equipment according to claim 1, wherein the comparison result of comparison circuit is output to half control type switching device
Gate pole, and the anode and cathode of half control type switching device is connected voltage and provides in path.
3. equipment according to claim 1, wherein measured value meets predetermined condition with reference value and includes:
The measured value is greater than or equal to reference value；Or
The measured value is less than or equal to reference value.
4. equipment according to claim 2, wherein the equipment further comprises:
Holding circuit, the signal of the gate pole for remaining applied to half control type switching device when the input voltage interrupts.
5. equipment according to claim 4, wherein the holding circuit includes resistance and capacitor.
6. equipment according to claim 1, wherein comparison circuit includes switching transistor, and the reference value is out
Close the threshold voltage of transistor.
7. a kind of method for protecting low-voltage circuit in misconnection alternating current, comprising:
Measure the input voltage of the alternating current-direct current of input；
The measured value of the input voltage of the alternating current-direct current of input is compared with reference value；And
When measured value and reference value meet predetermined condition, controlled by half control type switching device with by the input voltage
Low-voltage circuit is provided, after the half control type switching device normally, is not turned off as long as having electric current to flow through equipment,
Wherein, measurement input voltage includes utilizing a diode for filtering out alternating current after measurement input voltage is divided via bleeder circuit
The negative polarity portion of pressure simultaneously acquires the positive polarity portion of alternating voltage and is applied to the voltage of comparison circuit, as measured value,
Wherein, the bleeder circuit includes resistance.
8. according to the method described in claim 7, wherein, the method further includes:
The signal of the gate pole of half control type switching device is remained applied to when the input voltage interrupts.
9. according to the method described in claim 7, wherein, half control type switching device is remained applied to by resistance and capacitor
The signal of gate pole.
10. according to the method described in claim 7, wherein, comparison circuit includes switching transistor, and the reference value is out
Close the threshold voltage of transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410403621.4A CN105449632B (en) | 2014-08-15 | 2014-08-15 | For protecting the device and method of low-voltage circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410403621.4A CN105449632B (en) | 2014-08-15 | 2014-08-15 | For protecting the device and method of low-voltage circuit |
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| Publication Number | Publication Date |
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| CN105449632A CN105449632A (en) | 2016-03-30 |
| CN105449632B true CN105449632B (en) | 2019-02-15 |
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| CN201410403621.4A Active CN105449632B (en) | 2014-08-15 | 2014-08-15 | For protecting the device and method of low-voltage circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111416605B (en) * | 2019-01-06 | 2024-04-12 | 广州市金矢电子有限公司 | Semi-controlled device driving device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102780202A (en) * | 2011-05-09 | 2012-11-14 | 海洋王照明科技股份有限公司 | Overvoltage protection circuit and lamp |
| CN203166467U (en) * | 2013-03-20 | 2013-08-28 | 向智勇 | Overvoltage protection circuit |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11178197A (en) * | 1997-12-08 | 1999-07-02 | Hioki Ee Corp | Ac measuring apparatus |
| KR100828923B1 (en) * | 2001-10-10 | 2008-05-13 | 엘지디스플레이 주식회사 | Prevention Circuit of Over Voltage and Surge Voltage |
| CN202503261U (en) * | 2012-02-21 | 2012-10-24 | Tcl光电科技(惠州)有限公司 | Protective device of input voltage fluctuation |
| CN103852628B (en) * | 2012-11-28 | 2017-03-22 | 深圳市海洋王照明工程有限公司 | Overvoltage protection circuit and overvoltage detection circuit thereof |
| CN103916012B (en) * | 2014-04-01 | 2016-09-28 | 江苏杰瑞科技集团有限责任公司 | A kind of essential safety source conversion equipment |
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2014
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102780202A (en) * | 2011-05-09 | 2012-11-14 | 海洋王照明科技股份有限公司 | Overvoltage protection circuit and lamp |
| CN203166467U (en) * | 2013-03-20 | 2013-08-28 | 向智勇 | Overvoltage protection circuit |
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| CN105449632A (en) | 2016-03-30 |
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