CN208890364U - A kind of lightning protection overvoltage crowbar and protective device - Google Patents
A kind of lightning protection overvoltage crowbar and protective device Download PDFInfo
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- CN208890364U CN208890364U CN201821461193.0U CN201821461193U CN208890364U CN 208890364 U CN208890364 U CN 208890364U CN 201821461193 U CN201821461193 U CN 201821461193U CN 208890364 U CN208890364 U CN 208890364U
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Abstract
The utility model discloses a kind of lightning protection overvoltage crowbar and protective devices; protecting circuit includes the first piezoresistive wafer, the second piezoresistive wafer, Transient Suppression Diode, posive temperature coefficient thermistor piece and leading-out terminal; posive temperature coefficient thermistor piece is in parallel with the first piezoresistive wafer together again after connecting with Transient Suppression Diode; the series-parallel branch is connected with the second piezoresistive wafer again; form a single port combinational circuit; wherein, the performance of the first piezoresistive wafer tolerance surge impact is higher than the performance of the second piezoresistive wafer tolerance surge impact；At least one in two leading-out terminals of single port combinational circuit is the thermally conductive end of low thermal resistance, thermal coupling has the thermally conductive end of the low thermal resistance respectively for the posive temperature coefficient thermistor piece and/or the second varistor on piece, and the Transient Suppression Diode can be replaced Zener diode or voltage switch type element.
Description
Technical field
The utility model relates to field of power supplies, in particular to a kind of lightning protection overvoltage crowbar and protective device.
Background technique
A kind of low-voltage electrical apparatus of the Surge Protector (abbreviation SPD) as standard, is widely used in low pressure electric line,
The surge as caused by thunder and lightning etc. occurred in route effectively can be absorbed and be inhibited, to improvement grid power transmission quality, be protected
Card electrical appliance has safely apparent effect.
The core component of SPD is Surge suppression element, and the most commonly used is based varistor chips.Due to electric line
Transmission range is longer, but be easy to be exposed to it is outdoor, compared to indoor electric appliance equipment be easier by high-energy surge pulse, in SPD
Phase projected life in, based varistor chip be easier by be more than rated specification high-energy surge repeat impact,
Cause the deterioration failure of varistor.Since varistor is short circuit failure mode, once breakdown failure, will cause supply lines
Road short trouble, breakdown point will appear burst, smolder, arcing, it is serious when in addition will cause catching fire.
The schematic diagram of most common ameliorative way is shown in attached drawing 1, on two end electrodes of based varistor chip 1,
It being respectively welded and connects a piece of conductive and all excellent heating conduction scale copper electrode 2, scale copper electrode 2 is prefabricated with leading-out terminal 3,
Scale copper electrode 2 also forms thermal coupling with based varistor chip 1 while playing the role of conductive electrode, can be by pressure-sensitive electricity
The heat that resistance ceramic chip 1 generates is transmitted on leading-out terminal 3.It is welded on a leading-out terminal 3 with low-melting alloy 5 wherein
A piece of elastic sheet metal 4 forms overheat disconnector.When based varistor chip 1, which is deteriorated to leakage current, enters milliampere grade, open
Begin to enter accelerated deterioration area, leakage current can make the fever of based varistor chip 1 that leakage current be promoted to further increase, and accelerate
Based varistor chip 1 generates heat, and will finally make 1 thermal breakdown of based varistor chip.It is melted when heat reaches low-melting alloy 5
When disconnected temperature, disconnector action power dump is overheated, so that based varistor chip 1 is exited power grid before puncture short, reaches
The purpose of protection.The program can convert the failure mode of most based varistor chip 1 from pernicious short-circuit mode
For the open circuit mode for influencing very little, the safety of SPD is greatly improved.
But still there is also some defects for the program, since the movement of overheat disconnector needs to be delayed by several seconds the time, and
1 leakage current of based varistor chip enters milliampere grade and starts accelerated deterioration adstante febre, and the defect inside porcelain body is very serious
, there is the defect of partial chip seriously to arrive very short to the time of puncture short from starting to generate heat, heat also has little time to be transmitted to
Hot disconnector melts low-melting alloy 5, and short circuit accident just has occurred.Another much situation is exactly when pressure-sensitive electricity
Resistance ceramic chip 1 is deteriorated to when closing on accelerated deterioration area, and at this moment the leakage current of based varistor chip 1 is also less than milliampere grade,
It can also maintain thermostabilization, additionally it is possible to work is maintained under the operating voltage of power grid, but its pressure sensitive voltage value at this time has compared
Initial value when just starting to come into operation has apparent sharp fall, the anti-surge punching of based varistor chip 1 at this moment
The ability hit is very fragile, and an energy is not counting it can directly be punctured or close to breakdown by too big surge, at this time
Its puncture short speed is also that too fastly, overheat disconnector has little time response action and do not have protective effect.
Utility model content
The purpose of the utility model is to overcome the above-mentioned deficiencies in the presence of the prior art, provide a kind of lightning protection over-voltage guarantor
Protection circuit and protective device.
In order to achieve the above-mentioned object of the invention, the utility model provides following technical scheme:
A kind of lightning protection overvoltage crowbar, including the first piezoresistive wafer, the second piezoresistive wafer, transient state inhibit two poles
Pipe, posive temperature coefficient thermistor piece and leading-out terminal, the posive temperature coefficient thermistor piece and the transient state inhibit two poles
Pipe series connection after it is in parallel with first piezoresistive wafer together again, the series-parallel branch again with the second piezoresistive wafer string
Connection, forms a single port combinational circuit, wherein the performance of first piezoresistive wafer tolerance surge impact is higher than described the
Two piezoresistive wafers are resistant to the performance of surge impact；
At least one in two leading-out terminals of the single port combinational circuit is the thermally conductive end of low thermal resistance, the low-heat
Thermally conductive end is hindered to be thermally coupled to each other with one of them in second piezoresistive wafer, the posive temperature coefficient thermistor piece
Or it is thermally coupled to each other simultaneously with two.In use, in the thermally conductive end connection overheat disconnector of the low thermal resistance, the positive temperature system
The Curie point of number thermosensitive resistor film is higher than the operating temperature of the overheat disconnector.
The principle Analysis of the utility model is as follows:
It is the main channel for absorbing surge pulse by the series loop that the first piezoresistive wafer, the second piezoresistive wafer form,
When not having surge pulse, varistor is in high-impedance state, and when surge arrives, varistor is in low resistive state, surge energy
Amount thus release by circuit.At this point, the voltage-limiting protection level of SPD is regarded as the residual voltage value of the first piezoresistive wafer and second pressure-sensitive
The sum of residual voltage value of resistor disc.After surge disappears, piezoresistive wafer returns to high-impedance state.In order to ensure the member in surge channel
Device degradation in tolerance surge impact capacity selection, will should follow the first piezoresistive wafer since the second piezoresistive wafer
Tolerance be greater than the principle of the second piezoresistive wafer, significantly deteriorated with reaching when the second piezoresistive wafer, started to open
When dynamic Thermal protection circuit, the also substantially intact purpose of the first piezoresistive wafer.
Another circuit is to be connected by the second piezoresistive wafer, Transient Suppression Diode with posive temperature coefficient thermistor piece
Made of Thermal protection branch, and overheat disconnector is connected to by thermally conductive end.When the intact no surge of element, due in height
Not on-state is hindered, the leakage current for flowing through Thermal protection branch is minimum (microampere order), and Thermal protection branch does not generate heat.Even if when surge comes
Temporarily, since the posive temperature coefficient thermistor piece being serially connected in branch still has tens Dao several hundred ohm resistance value at normal temperature,
And its dynamic electric resistor can be several ohm down to zero point in the case where absorbing surge on state for the first piezoresistive wafer connected in parallel, it is big absolutely
Part surge current passes through from the first piezoresistive wafer, and posive temperature coefficient thermistor piece and Transient Suppression Diode series connection
The voltage at branch both ends is also limited in the residual voltage value of the first piezoresistive wafer, flows through the surge current of Thermal protection branch at this
At most namely pacify times grade under part, the heat that thermistor generates in a short period of time is minimum and surge just disappears, and heat is protected
Shield branch can be failure to actuate because fever is faint.
The Analysis of Failure Mechanism of the utility model is as follows:
When the second piezoresistive wafer significantly deteriorates, pressure sensitive voltage value declines to a great extent, the pressure sensitive voltage of the second piezoresistive wafer
After value is superimposed with the turn-on voltage of Transient Suppression Diode, when being still below network operation voltage peak, in Thermal protection branch
Transient Suppression Diode is converted on state by off state rapidly, and the first piezoresistive wafer still is able to maintain high resistant shape
State.At this point, the electric current for flowing through Thermal protection branch increases sharply, and after the action current for reaching posive temperature coefficient thermistor, positive temperature
Degree coefficient resistance is brought rapidly up, and the resistance value of posive temperature coefficient thermistor piece rises rapidly, and makes to flow through Thermal protection branch
Electric current quickly reduces, and finally reaches thermal balance above Curie point, and heat can be stablized, constantly from thermally conductive end biography
Overheat disconnector is led, temperature can achieve near Curie temperature, and the operating temperature for overheating disconnector is set below Curie's temperature
At degree, can reliably disengaging it act, so that the SPD deteriorated be made to be detached from power network line.The technical program can make major part
SPD after deterioration exits power grid in this safe mode.
For those much special circumstances, i.e., when the second piezoresistive wafer deteriorates to a certain extent or has located
When accelerated deterioration area, its anti-impulse ability has declined to a great extent at this time, and stronger surge of energy can be
It directly punctures or close breakdown.When surge disappear after, due to resistance to surge impact capacity it is stronger and substantially intact than it first
Piezoresistive wafer still is able to maintain high-impedance state, and thermostabilization is maintained in power grid, significant degradation phenomena does not occur, electric at this time
Net operating voltage still will be applied to Thermal protection branch both ends, since the conducting voltage of Transient Suppression Diode is set as being less than electricity
Net crest voltage, still being able to turnover is on state, and the electric current increased rapidly still can make posive temperature coefficient thermistor fast
Speed heats up and reaches thermal balance, it still can generate heat to Curie point and make to overheat disconnector movement, and overheat disconnector will
Action power dump makes the SPD of damage safely exit power grid.Due to overheat disconnector be generally provided with positioning indicator or
Person's electricity, sound, light warning device, will soon be found, and maintenance personal replaces in which can be convenient, and reach safe handling
Purpose.To substantially increase the safety and reliability of SPD, the electrical equipment crash rate connected on route also will significantly subtract
It is small.
Bipolarity Transient Suppression Diode is used when for communication environment, can use unipolarity pipe under DC environment.Institute
State the breakdown voltage value V of Transient Suppression DiodeBRLess than the network operation voltage peak accessed, second piezoresistive wafer
Maximum continuous direct-current working volts value and the Transient Suppression Diode maximum reverse operating voltage value VRWMThe sum of be greater than institute
The network operation voltage peak of access.
Further, the posive temperature coefficient thermistor piece could alternatively be the resistance of linear feature, linear special
The electric current of the resistance of sign is substantially proportional to voltage, i.e., its characteristic equation is mainly linear homogeneous, and defers to Ohm's law.
The resistance of linear feature can also play the role of following in Thermal protection branch: first is that metering function, when described second pressure-sensitive
After resistor disc accelerated deterioration even puncture short, the resistance of linear feature can pacify the current limit in Thermal protection branch
Within total head, it not will cause the lightning protection overvoltage crowbar short circuit and burn；Second is that heating functioin, the electric current within safety value is held
The continuous resistance by second piezoresistive wafer and linear feature, which will be such that they are warming up to, makes to overheat disconnector movement, together
Sample can achieve the purpose of Thermal protection.To reach said effect, the current value of Thermal protection branch in the most adverse case (second
Piezoresistive wafer puncture short) it is advisable for tens milliamperes to several amperes, the resistance value of the resistance of corresponding linear feature is several
Kilohm to tens ohm.
In the present invention, the resistance of linear feature both includes linear resistance, also allow containing it is some it is non-linear at
Divide (non-linear component is smaller, mainly still embodies Ohm's law feature), but power is required to want sufficiently large, pressure resistance is wanted
It is sufficiently high, at least to adhere to that failure cannot be damaged before overheating disconnector movement.
Preferably, the Transient Suppression Diode can be replaced other voltage limiting type elements, such as Zener diode,
When not having surge, voltage limiting type element has high impedance, but with the raising of surge current and voltage, voltage limiting type element
Impedance by the reduction of duration.Using the bipolarity Zener diode of back-to-back connection, DC environment when for communication environment
Under can use unipolarity pipe, the voltage of voltage regulation value V of the Zener diodeZLess than the network operation voltage peak accessed.
The reverse snapback voltage value V of the maximum of second piezoresistive wafer continuous direct-current working volts value and the Zener diodeR
The sum of be greater than accessed network operation voltage peak.
The voltage limiting type element (including Transient Suppression Diode and Zener diode etc.) for being serially connected in Thermal protection branch is main
Play two, first is that adjusting the sensitivity of Thermal protection branch starting；It is accessed second is that adjusting the tolerance of single port combinational circuit
The ability of voltage ripple of power network.The turn-on voltage of voltage limiting type element selects lower, and Thermal protection branch starts more early,
Second piezoresistive wafer is not deteriorated to also close to just movement is detached from power grid when breakdown.But the conducting voltage of voltage limiting type element
Value can not be selected excessively high, once choosing value be higher than power grid crest voltage after, even if the second piezoresistive wafer deteriorated breakdown it is short
Lu Liao, voltage limiting type element can also maintain off state to be not turned on, and Thermal protection branch is just passivated and fails.
Since the maximum continuous work voltage value in single port combinational circuit is continuous by the maximum of the second piezoresistive wafer
Operating voltage value and the maximum of voltage limiting type element are not turned on the sum of voltage value to determine, and the second piezoresistive wafer is in electricity
It gushes and absorbs on major loop, pressure sensitive voltage value (being proportional to maximum continuous work voltage value) should not select get Tai Gao, in order to avoid increase residual
Pressure value influences level of protection.Therefore, the maximum of voltage limiting type element can be not turned on voltage value and selects Gao Yidian, to be resistant to
Access the erratic fluctuations of network operation voltage.
Due to when surge is impacted, the series connection Thermal protection branch of posive temperature coefficient thermistor piece and voltage limiting type element
Impedance it is higher, both ends again by the first piezoresistive wafer residual voltage protect, so hardly by surge damage, positive temperature system
Number thermosensitive resistor films diameter can select it is a little bit smaller, as long as can ensure to generate enough heats make overheat disconnector movement before
It puts, a little bit smaller action current that can make thermistor of diameter is a little bit smaller, smaller to the impact of voltage limiting type element.
And choosing can be considered greatly a bit in the power of voltage limiting type element, although being possible to quilt in the moment that Thermal protection starts conducting turnover
Excessive action current puncture short, but do not influence the effect of heat protection function, or even positive temperature coefficient can also be made hot at all
Quick resistance quickly reaches thermal balance.Only power choosing is big a little can generate mechanical damage to avoid the rush of current of turnover moment
Wound, to influence the reliability of circuit.
Preferably, the Transient Suppression Diode can be replaced voltage switch type element, and when not having surge, the voltage is opened
Pass type element has high impedance, and when there is surge, the voltage switch type element can be immediately converted as Low ESR.At this point, this reality
It is as follows with novel Analysis of Failure Mechanism:
When the second piezoresistive wafer does not deteriorate or pressure sensitive voltage value is deteriorated to not yet lower than accessed network voltage
When a certain ratio of peak value, surge each time is arrived, although voltage switch type element will be connected, the second varistor at this time
Piece can also pincers power-off net follow current, surge disappear after, voltage switch type element can return to off-state, Thermal protection branch
Road is of short duration conducting, and the shortage of heat of generation is so that thermistor temp is increased significantly.When pressure sensitive voltage value is further bad
After change, the impact of surge next time is possible to the power grid follow current after the continuous voltage switch type element conductive of pincers, voltage switch
Type element does not return to off-state, and the electric current for flowing through Thermal protection branch has been more than the movement electricity of posive temperature coefficient thermistor
Stream, makes it be rapidly reached the heat balance point of near Curie temperature, and heat can be transmitted to overheat from thermally conductive end at leisure and be detached from
Device makes overheat disconnector reliably act disengaging, the SPD deteriorated is made safely to exit power grid.
For those much special circumstances, i.e., when the second piezoresistive wafer deteriorates to a certain extent or has located
When accelerated deterioration area, its anti-impulse ability has declined to a great extent at this time, and stronger surge of energy can be
It punctures or close to breakdown, it also loses the follow current that voltage switch type element is flowed through in the disconnected Thermal protection branch of pincers at this time
Ability.After surge disappears, since resistance to surge impact capacity first piezoresistive wafer stronger and substantially intact than it still can
High-impedance state is enough maintained, thermostabilization is maintained in power grid, significant degradation phenomena does not occur.Network operation voltage is still applied at this time
Thermal protection branch both ends are added in, and voltage switch type element stills remain on state, posive temperature coefficient thermistor will
It is rapidly heated and reaches thermal balance near Curie temperature, to make to overheat disconnector action power dump, make the SPD safety of damage
Ground exits power grid.
The breakdown turn-on voltage for being serially connected in the voltage switch type element in Thermal protection branch will be with the first piezoresistive wafer
Pressure sensitive voltage value it is substantially uniform.If that chooses is too high, needs biggish surge by the first piezoresistive wafer, just have foot
Enough high residual voltage values make its breakdown conducting, influence the sensitivity of Thermal protection branch starting；If that chooses is too low, itself and the can be made
The sum of maximum continuous work voltage value of two piezoresistive wafers reduces, and influences single port combinational circuit and is resistant to accessed network operation
The ability of spread of voltage fluctuation.Due to the surge current very little in thermistor and voltage switch type element series arm, electricity
The type element of compressing switch can choose the lesser miniaturized element of through-current capacity and be sufficient.
Preferably, the voltage-type switching mode element is gas-discharge tube.The pressure sensitive voltage of second piezoresistive wafer
Value is greater than the 50% of accessed network operation voltage peak.
Preferably, the pressure sensitive voltage value of first piezoresistive wafer is the 0.9 of accessed network operation voltage peak
To 1.1 times.It can guarantee in the case where the second piezoresistive wafer thorough puncture short, after surge disappearance, the first pressure-sensitive electricity
Resistance piece can also maintain high-impedance state, and thermostabilization is maintained in power grid, does not occur significantly to deteriorate, and be the movement of Thermal protection branch
The sufficient response time is provided, the safety of single port combinational circuit is improved.When the pressure sensitive voltage value of the first piezoresistive wafer is selected
When obtaining too low, it cannot be guaranteed that securely maintaining thermostabilization in the case, when selecting excessively high, single port overvoltage protector can be improved
The limitation voltage indexes of part, influence level of protection.
Specifically, the pressure sensitive voltage value of first piezoresistive wafer is 280V-342V, access 220V can be applied to
When power grid；Alternatively, the pressure sensitive voltage value of first piezoresistive wafer is 140V-171V, access 110V electricity can be applied to
When net；Alternatively, the pressure sensitive voltage value of first piezoresistive wafer is 484V-591V, access 380V power grid can be applied to
When.
Preferably, between second piezoresistive wafer and the posive temperature coefficient thermistor piece by conduction material into
Row heat transfer.The heat generated when second piezoresistive wafer can be started accelerated deterioration by conduction material is conducted to institute
Posive temperature coefficient thermistor piece is stated, so that the resistance value of posive temperature coefficient thermistor piece be made to rise, shortens positive temperature coefficient
Thermosensitive resistor film reaches the time of Curie point, and can reduce its action current.Realize that the substance of this heat conduction has
Various ways, such as all interconnectors can be designed as low thermal resistance conducting wire, the second piezoresistive wafer can be generated
Heat is transmitted to the entire lightning protection overvoltage crowbar, also just contains the posive temperature coefficient thermistor piece.It can also
An electrode surface of the posive temperature coefficient thermistor piece to be projected in an electrode surface of second piezoresistive wafer
On, centre is inserted into a piece of conduction material gasket and is again sequentially fixed at them together, and the heat that the second piezoresistive wafer generates is just
Posive temperature coefficient thermistor piece can be conducted to by conduction material gasket.Conduction material gasket can be aluminium oxide ceramics
Piece or other insulating materials, it might even be possible to be voltage-sensitive ceramic piece, as long as by the Transient Suppression Diode short circuit or not influencing it
Work can.
Preferably, the impact resistance current rating of first piezoresistive wafer is higher than the resistance to of second piezoresistive wafer
Dash current rated value.
Preferably, the first piezoresistive wafer electrode surface area of first piezoresistive wafer is greater than the described second pressure-sensitive electricity
Hinder the second piezoresistive wafer electrode surface area of piece.Measuring piezoresistive wafer tolerance surge impact capacity has multinomial technical indicator,
It is main to have: dash current Iimp, current waveform is 10/350 μ s；Maximum discharge current Imax, current waveform is 8/20 μ s；Energy
Tolerance, current waveform are 2ms square wave；Rush of current stability is exactly with 8/20 μ s waveform nominal discharge current In repeated impacts
The number etc. being resistant to.Under identical geometric dimension, by adjusting ceramic formula or technological parameter can optimize one of them or
Multiple parameters index, but want General Promotion or relatively difficult.But these technical indicators are all and varistor plate electrode
Area is directly proportional, therefore, as long as increasing the area of the first varistor plate electrode under the conditions of same process, so that it may ensure to be resistant to
Surge impact capacity is comprehensively more than the second piezoresistive wafer.
Preferably, the nominal diameter of first piezoresistive wafer is nominal straight at least more than second piezoresistive wafer
One sequence number of diameter.Since the diameter of flanking sequence number is than about 1.25 times, they are resistant to the parameter difference of surge impact capacity
About 1.5 times, as long as the second piezoresistive wafer is designed to match with application environment, then the first piezoresistive wafer belongs to
Redundancy Design, crash rate will be reduced than the second piezoresistive wafer in the order of magnitude, so that it may which guarantee makes the second piezoresistive wafer first
Deterioration.
The invention also discloses a kind of lightning protection over-pressure safety device, the lightning protection over-pressure safety device uses any
A kind of above-mentioned lightning protection overvoltage crowbar.Specifically, being connected on an electrode surface of second piezoresistive wafer described
One electrode of Transient Suppression Diode and first piezoresistive wafer, on another electrode of the Transient Suppression Diode
It is connected with the posive temperature coefficient thermistor piece, is connected on another electrode of the posive temperature coefficient thermistor piece
State another electrode of the first piezoresistive wafer, second piezoresistive wafer and/or the posive temperature coefficient thermistor piece
On be also welded with the thermally conductive end of low thermal resistance, to realize the thermal coupling of element.The Transient Suppression Diode can be replaced Zener two
Pole pipe or voltage switch type element, the connection of element preferentially select directly to weld between electrode surface, and inside connection few as far as possible is drawn
Line or conducting bracket.
Preferably, first piezoresistive wafer, second piezoresistive wafer, the Transient Suppression Diode are (or neat
Receive diode or voltage switch type element), the posive temperature coefficient thermistor piece be packaged as a whole, will be removed with insulating materials
Remaining surface outside two leading-out terminals wraps up in envelope.
Preferably, the thermally conductive end of low thermal resistance with thermally conductive function has foot using excellent materials of heating conductions such as copper
Enough big cross-sectional areas.And pyrotoxin (piezoresistive wafer or positive temperature coefficient temperature-sensitive are connected to using thermal couplings modes such as welding
On resistor disc), and distance of the thermally conductive end away from pyrotoxin will as far as possible it is short, to obtain minimum thermal resistance, guarantee has enough
Heat is transmitted to overheat disconnector.
Preferably, an electrode surface of second piezoresistive wafer connects first varistor by conducting bracket
One electrode of piece；Another electrode of the posive temperature coefficient thermistor piece connects first pressure by internal connection line
Another electrode of quick resistor disc.
Compared with prior art, the utility model has the beneficial effects that
The utility model is equipped with the absorption surge arteries and veins being composed in series by the first piezoresistive wafer, the second piezoresistive wafer simultaneously
The main channel of punching, and by the second piezoresistive wafer, Transient Suppression Diode (Zener diode or voltage switch type member
Part), the Thermal protection branch that is connected in series of posive temperature coefficient thermistor piece, and two branch circuit parallel connections.In conventional failure conditions and
Under special failure conditions, the overheat disconnector of SPD can action power dump so that SPD finally exits circuit with open circuit mode,
Relative to traditional short-circuit mode, greatly improve the safety of SPD, it is therefore prevented that short circuit breakdown when generate smolder, arcing,
The even serious accident of catching fire.Meanwhile positioning indicator or electricity, sound, light warning device that disconnector is equipped with are overheated,
So that the SPD of damage will soon be found, maintenance personal replaces in which can be convenient, and has achieved the purpose that safe handling,
To substantially increase the safety and reliability of SPD, the electrical equipment crash rate connected on route also will significantly reduce.
In addition, the voltage limiting type element (or voltage switch type element) for being serially connected in Thermal protection branch mainly plays two works
With first is that adjusting the sensitivity of Thermal protection branch starting；Second is that adjusting single port combinational circuit is resistant to accessed network voltage wave
Dynamic ability.
Detailed description of the invention:
Fig. 1 is the schematic illustration of improvement plan one described in the prior art.
It is marked in Fig. 1: 1- based varistor chip, 2- scale copper electrode, 3- leading-out terminal, 4- elastic sheet metal, 5-
Low-melting alloy.
Fig. 2 is a kind of schematic diagram of lightning protection overvoltage crowbar described in the utility model embodiment 1.
Fig. 3 is a kind of schematic diagram of lightning protection overvoltage crowbar described in the utility model embodiment 2.
Fig. 4 is a kind of schematic diagram of lightning protection overvoltage crowbar described in the utility model embodiment 3.
Fig. 5 is a kind of part drawing of lightning protection over-pressure safety device described in the utility model embodiment 4.
Fig. 6 is a kind of assembling figure of lightning protection over-pressure safety device described in the utility model embodiment 4.
It is marked in Fig. 2-Fig. 6: the first piezoresistive wafer of 1-, 11- the first piezoresistive wafer electrode surface, the second varistor of 2-
Piece, 21- the second piezoresistive wafer electrode surface, 3- Transient Suppression Diode, 4- posive temperature coefficient thermistor piece, 5- exit
Son, 6- internal connection line, 7- conducting bracket.
Specific embodiment
The utility model is described in further detail below with reference to test example and specific embodiment.But it should not be by this
The range for being interpreted as the above-mentioned theme of the utility model is only limitted to embodiment below, all to be realized based on the content of the present invention
Technology belongs to the scope of the utility model.
Embodiment 1
As shown in Fig. 2, a kind of lightning protection overvoltage crowbar, including the first piezoresistive wafer 1, the second piezoresistive wafer 2, wink
State inhibits diode 3, posive temperature coefficient thermistor piece 4 and leading-out terminal 5, the posive temperature coefficient thermistor piece 4 and institute
State in parallel with first piezoresistive wafer 1 together again after Transient Suppression Diode 3 is connected, the series-parallel branch is again with described the
The series connection of two piezoresistive wafers 2, forms a single port combinational circuit, wherein first piezoresistive wafer 1 is resistant to surge impact
Performance be higher than second piezoresistive wafer 2 tolerance surge impact performance.
Two leading-out terminals 5 of the single port combinational circuit are the thermally conductive end of low thermal resistance, the thermally conductive end of low thermal resistance
Head is thermally coupled to each other with second piezoresistive wafer 2, meanwhile, the thermally conductive end of low thermal resistance and the positive temperature coefficient temperature-sensitive
Resistor disc 4 is thermally coupled to each other.
The pressure sensitive voltage value of first piezoresistive wafer 1 is the 0.9 to 1.1 of accessed network operation voltage peak
Times；The turn-on voltage of the Transient Suppression Diode 3 is less than accessed network operation voltage peak；The second pressure-sensitive electricity
The continuous direct-current working volts value of maximum of resistance piece 2 and the maximum of the Transient Suppression Diode 3 are not turned on the sum of voltage value and are greater than
The network operation voltage peak accessed.
The Transient Suppression Diode 3 can be replaced Zener diode or voltage switch type element, the voltage switch type
Element can be chosen for gas-discharge tube.
Embodiment 2
As shown in figure 3, the present embodiment the difference from embodiment 1 is that, two exits of the single port combinational circuit
Sub 5 only ones are the thermally conductive end of low thermal resistance, and the thermally conductive end of the low thermal resistance and the mutual thermal coupling of second piezoresistive wafer 2
It closes.
Embodiment 3
The present embodiment the difference from embodiment 1 is that, two 5 only ones of leading-out terminal of the single port combinational circuit are
The thermally conductive end of low thermal resistance, the thermally conductive end of low thermal resistance and the posive temperature coefficient thermistor piece 4 are thermally coupled to each other (such as Fig. 4
It is shown).
Embodiment 4
As shown in Fig. 5-Fig. 6, one of a kind of lightning protection over-pressure safety device, second piezoresistive wafer 2 is second pressure-sensitive
It is connected with the Transient Suppression Diode 3 on resistor disc electrode surface 21, while the first piezoresistive wafer is connected by conducting bracket 7
A 1 first piezoresistive wafer electrode surface 11 is connected with the positive temperature on another electrode of the Transient Suppression Diode 3
Coefficient resistance piece 4 is spent, another electrode of the posive temperature coefficient thermistor piece 4 is connected with by internal connection line 6
Another the first piezoresistive wafer electrode surface 11 of first piezoresistive wafer 1, second piezoresistive wafer 2 and/or institute
It states and is also welded with leading-out terminal 5 on posive temperature coefficient thermistor piece 4, wherein at least one is the thermally conductive end of low thermal resistance.It is described
It is connected between second piezoresistive wafer 2 and first piezoresistive wafer 1 by conducting bracket 7, the conducting bracket 7 is groove
Structure is equipped with the Transient Suppression Diode 3 and posive temperature coefficient thermistor piece 4 in the groove of the conducting bracket 7,
Finally again by the first piezoresistive wafer 1, second piezoresistive wafer 2, the Transient Suppression Diode 3, the positive temperature system
Number thermosensitive resistor film 4 is packaged as a whole.
Specifically, the pressure-sensitive tile (40K331x2) of square of the first piezoresistive wafer 1 selection two panels nominal diameter 40mm
For equivalent substitution to reduce mounting area, which is that the industry is the routine side for reducing mounting area and using after parallel connection
Formula can also directly adopt the pressure-sensitive tile of rectangle certainly, and pressure sensitive voltage is 330 volts, and maximum discharge current Imax is 80KA；The
Two piezoresistive wafers 2 select the pressure-sensitive tile 40K331 of square of nominal diameter 40mm, and pressure sensitive voltage is 330 volts, maximum electric discharge
Electric current Imax is 40KA；Transient Suppression Diode 3 selects VRWM=200V, VBRThe two-way transient state suppression of the axial lead plastic packaging of=220V
Diode processed, 160 DEG C of Curie point of the selection of posive temperature coefficient thermistor 4,150 ohm of room temperature resistance value, the circle of diameter 10mm
Piece.Reference selection is suitble to work in 220 volts of common frequency power networks, and the operating temperature of overheat disconnector matched with its is 120 DEG C.
Package unit is connected on 220 coucher frequency routes, and applies the surge repeated impacts of In=20KA, the 90th punching
Disconnector movement is overheated after hitting, and is cooled to and is tested the pressure sensitive voltage value of the second piezoresistive wafer 2 after room temperature to be that 0 ambuscade is worn short
Road, and the first piezoresistive wafer 1 is still 329 volts, is remained unchanged substantially.
Preferably, 3 Zener diode of Transient Suppression Diode or voltage switch type element, the voltage switch type member
Part can be chosen for gas-discharge tube.
Embodiment 5
The present embodiment and the difference of embodiment 4 are that second piezoresistive wafer 2 and the positive temperature coefficient temperature-sensitive are electric
Heat transfer is carried out by conduction material between resistance piece 4.Such as all interconnectors 6 can be designed as low thermal resistance conducting wire,
The heat that second piezoresistive wafer 2 generates can be transmitted to the entire lightning protection over-pressure safety device, also just contained described
Posive temperature coefficient thermistor piece 4.One electrode surface of the posive temperature coefficient thermistor piece 4 can also be projected in described
On one electrode surface of the second piezoresistive wafer 2, centre is inserted into a piece of conduction material gasket and is again sequentially fixed at them together,
The heat that second piezoresistive wafer 2 generates can be conducted to posive temperature coefficient thermistor piece 4 by conduction material gasket.
Conduction material gasket can be alumina ceramic plate or other insulating materials, it might even be possible to be voltage-sensitive ceramic piece, as long as not by institute
Stating the short circuit of Transient Suppression Diode 3 or influence that it works can.
Above embodiments are only to illustrate the utility model and not limit technical solution described in the utility model, to the greatest extent
Pipe this specification has been carried out detailed description to the utility model referring to above-mentioned each embodiment, but the utility model not office
It is limited to above-mentioned specific embodiment, therefore any pair of the utility model is modified or equivalent replacement；And all do not depart from it is practical
The technical solution and its improvement of novel spirit and scope, should all cover in the scope of the claims of the utility model.
Claims (10)
1. a kind of lightning protection overvoltage crowbar, including the first piezoresistive wafer (1), the second piezoresistive wafer (2), transient state inhibit two
Pole pipe (3), posive temperature coefficient thermistor piece (4) and leading-out terminal (5), which is characterized in that the positive temperature coefficient temperature-sensitive electricity
Resistance piece (4) is in parallel with the first piezoresistive wafer (1) together again after connecting with the Transient Suppression Diode (3), and the string is simultaneously
Connection branch is connected with second piezoresistive wafer (2) again, forms a single port combinational circuit, wherein described first is pressure-sensitive
The performance that resistor disc (1) is resistant to surge impact is higher than the performance of second piezoresistive wafer (2) tolerance surge impact；
At least one in two leading-out terminals (5) of the single port combinational circuit is the thermally conductive end of low thermal resistance, the positive temperature
Thermal coupling has the thermally conductive end of the low thermal resistance respectively on degree coefficient resistance piece (4) and/or the second piezoresistive wafer (2).
2. a kind of lightning protection overvoltage crowbar according to claim 1, which is characterized in that the Transient Suppression Diode
(3) Zener diode or voltage switch type element be can be replaced.
3. a kind of lightning protection overvoltage crowbar according to claim 2, which is characterized in that the voltage switch type element is
Gas-discharge tube.
4. a kind of lightning protection overvoltage crowbar according to claim 1, which is characterized in that first piezoresistive wafer
(1) pressure sensitive voltage value is 0.9 to 1.1 times of accessed network operation voltage peak.
5. a kind of lightning protection overvoltage crowbar according to claim 1, which is characterized in that first piezoresistive wafer
(1) pressure sensitive voltage value is 280V-342V, when can be applied to access 220V power grid；
Alternatively, the pressure sensitive voltage value of first piezoresistive wafer (1) is 140V-171V, access 110V electricity can be applied to
When net；
Alternatively, the pressure sensitive voltage value of first piezoresistive wafer (1) is 484V-591V, access 380V electricity can be applied to
When net.
6. -5 any a kind of lightning protection overvoltage crowbar according to claim 1, which is characterized in that the second pressure-sensitive electricity
Heat transfer is carried out by conduction material between resistance piece (2) and the posive temperature coefficient thermistor piece (4).
7. -5 any a kind of lightning protection overvoltage crowbar according to claim 1, which is characterized in that the first pressure-sensitive electricity
The first piezoresistive wafer electrode surface (11) area for hindering piece (1) is greater than the second varistor of second piezoresistive wafer (2)
Plate electrode face (21) area.
8. -5 any a kind of lightning protection overvoltage crowbar according to claim 1, which is characterized in that the first pressure-sensitive electricity
Hinder nominal diameter one sequence number of the nominal diameter at least more than second piezoresistive wafer (2) of piece (1).
9. -5 any a kind of lightning protection overvoltage crowbar according to claim 1, which is characterized in that the positive temperature coefficient
Thermosensitive resistor film (4) can be replaced the resistance of linear feature.
10. a kind of lightning protection over-pressure safety device, which is characterized in that using a kind of lightning protection as described in claim 1-9 is any
Voltage protection circuit.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109066638A (en) * | 2018-08-20 | 2018-12-21 | 成都铁达电子股份有限公司 | A kind of lightning protection overvoltage crowbar and protective device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109066638A (en) * | 2018-08-20 | 2018-12-21 | 成都铁达电子股份有限公司 | A kind of lightning protection overvoltage crowbar and protective device |
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