CN204205546U - A kind of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device - Google Patents
A kind of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device Download PDFInfo
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- CN204205546U CN204205546U CN201420626390.9U CN201420626390U CN204205546U CN 204205546 U CN204205546 U CN 204205546U CN 201420626390 U CN201420626390 U CN 201420626390U CN 204205546 U CN204205546 U CN 204205546U
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Abstract
The utility model discloses a kind of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device, comprise the semistor sheet, negative tempperature coefficient thermistor sheet and the piezoresistive wafer that are positioned at encapsulated layer; The first surface electrode of described semistor sheet is close to the first surface electrode of piezoresistive wafer and is electrically connected, and forms common port, and is drawn by the first lead-in wire; Second electrode of described semistor sheet is close to the first surface electrode of negative tempperature coefficient thermistor sheet and is electrically connected; Second electrode of described piezoresistive wafer is drawn by the second lead-in wire; Second electrode of described negative tempperature coefficient thermistor sheet is drawn by the 3rd lead-in wire.The utility model not only can prevent power-frequency overvoltage to produce destruction to circuit, and has overcurrent protection concurrently, compared with prior art; equal operating current; device volume reduces greatly, in other words the device of equal volume, and the operating current that can bear increases greatly.
Description
Technical field
The utility model relates to the over-voltage and over-current protector part of power-supply system, particularly one pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device.
Background technology
Piezo-resistance absorbs lightning induction pulse, transient overvoltage etc. because the nonlinear characteristic with excellence is applied in various electronic circuit.But because various abnormal cause often causes piezoresistor failure blast even on fire, pressure sensitive voltage and diameter generally by improving piezo-resistance solve this problem.But so just reduce the protection range that varistor absorbs surge voltage to a certain extent, and add cost.
Existing document: " Lu Zhenya, the Combination application of varistor and PTCR thermistor, electronic component and material, 1997.12 " openly report some result of the tests of varistor and PTC themistor Combination application.Chinese patent 201220290529.8 discloses a kind of compound over-voltage over-current protection assembly, by PTC thermistor and piezo-resistance are packaged together, electric current when utilizing piezo-resistance overvoltage to respond and temperature improve the overcurrent protection speed of PTC thermistor, and protect piezo-resistance conversely; Utilize PTC thermistor and piezo-resistance thermal coupling effect, the two gives mutual protection, and can play over-current over-voltage protection effect simultaneously.
But, this temperature-sensitive pressure-sensitive combination over-current over-voltage protection assembly existing defects that prior art manufactures and weak point: the power-frequency overvoltage performance that the PTC thermistor non-operating current selected is subject to varistor limited, when PTC thermistor non-operating current is larger, when its room temperature resistance is less or volume is larger, the energy absorbed needed for the switching process of thermistor from low-resistance to high resistant is larger, this just needs the piezo-resistance selecting volume larger, otherwise piezo-resistance will overheatedly be burnt before PTC thermistor switch motion, therefore, for the piezo-resistance of certain specification, with the use of the non-operating current of PTC thermistor be restricted, or, for the PTC thermistor of certain non-operating current, the piezo-resistance that volume is enough large must be selected, otherwise piezo-resistance was understood thermal explosion and was burnt before PTC thermistor switch motion.The maximum operating currenbt of the circuit that the non-operating current of this three terminal device is protected by it, therefore the maximum operating currenbt of protected circuit is subject to the restriction of device volume.
Utility model content
In order to overcome the above-mentioned shortcoming of prior art with not enough; the purpose of this utility model is to provide a kind of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device; overvoltage excess current protective function can be realized simultaneously; and compared with prior art; equal operating current; device volume reduces greatly, in other words the device of equal volume, and the operating current that can bear increases greatly.
The purpose of this utility model is achieved through the following technical solutions:
A kind of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device, comprise semistor sheet, negative tempperature coefficient thermistor sheet and piezoresistive wafer, described semistor sheet, negative tempperature coefficient thermistor sheet and piezoresistive wafer are positioned at encapsulated layer; The first surface electrode of described semistor sheet is close to the first surface electrode of piezoresistive wafer and is electrically connected, and forms common port, and is drawn by the first lead-in wire; Second electrode of described semistor sheet is close to the first surface electrode of negative tempperature coefficient thermistor sheet and is electrically connected; Second electrode of described piezoresistive wafer is drawn by the second lead-in wire; Second electrode of described negative tempperature coefficient thermistor sheet is drawn by the 3rd lead-in wire; Described second lead-in wire and the 3rd lead-in wire are input, and the first lead-in wire and the second lead-in wire are output, and output connects protected circuit.
The first surface electrode of described semistor sheet is connected by soldering-tin layer with the first surface electrode of piezoresistive wafer.
The first surface electrode of described semistor sheet is bonding by conductive electrode slurry with the first surface electrode of piezoresistive wafer.
Second electrode of described semistor sheet is connected by soldering-tin layer with the first surface electrode of negative tempperature coefficient thermistor sheet.
Second electrode of described semistor sheet is bonding by conductive electrode slurry with the first surface electrode of negative tempperature coefficient thermistor sheet.
Described encapsulated layer is silicones encapsulated layer, selects silicones than adopting epoxy resin, fire-retardant, heat-resisting and heat conductivility is better.
Operation principle of the present utility model is as follows: when two input inputs of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device assembly of the present utility model exceed the overvoltage of normal range of operation; piezo-resistance conducting; three elements all can generate heat; the semistor sheet mediated is except self heating power; piezoresistive wafer and the negative tempperature coefficient thermistor sheet that also can absorb both sides conduct the heat of coming; impel this semistor sheet to enter high-impedance state, cut off the current path of protected load end.And when input voltage recovers normal working voltage scope, piezoresistive wafer recovers high-impedance state, semistor can return to again low resistance state makes protected circuit recover normal work.When the protected circuit malfunctions of the utility model assembly causes operating current to increase above assembly non-operating current, semistor sheet enters high-impedance state and plays the cut-out function of current.Therefore the utility model device has over-voltage and over-current comprehensive protection function concurrently.
Compared with prior art, the utility model has the following advantages and beneficial effect:
The utility model improves its non-operating current by adopting compared with the thermosensitive resistor film of low-resistance value, punctured to protect piezoresistive wafer to exempt from energy by negative tempperature coefficient thermistor restriction initial current, its conducting under the load that can bear is made to generate heat and conduct heat on semistor sheet, power-frequency overvoltage not only can be prevented to produce destruction to circuit, and have overcurrent protection concurrently, and, compared with existing over-voltage and over-current protector part, equal operating current, device volume reduces greatly, the device of equal volume in other words, the operating current that can bear increases greatly.
Accompanying drawing explanation
Fig. 1 is the front schematic view of the pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device of embodiment 1 of the present utility model.
Fig. 2 is the generalized section of the pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device of embodiment 1 of the present utility model.
Fig. 3 is the typical application circuit of the pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device of embodiment 1 of the present utility model.
Embodiment
Below in conjunction with embodiment, the utility model is described in further detail, but execution mode of the present utility model is not limited thereto.
Embodiment 1
As shown in Fig. 1 ~ Fig. 2, the pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device of the present embodiment, comprise piezoresistive wafer 1, PTC thermistor sheet 2 and NTC thermistor sheet 3, described piezoresistive wafer 1, PTC thermistor sheet 2 and NTC thermistor sheet 3 are positioned at encapsulated layer 4; The first surface electrode of described piezoresistive wafer 1 is close to the first surface electrode of PTC thermistor sheet 2 and is electrically connected, and forms common port, and is drawn by lead-in wire 5; Second electrode of described PTC thermistor sheet 2 is close to the first surface electrode of NTC thermistor sheet 3 and is electrically connected; Second electrode of described piezoresistive wafer 1 is drawn by lead-in wire 6; Second electrode of described NTC thermistor sheet 3 is drawn by lead-in wire 7; Described lead-in wire 6 and lead-in wire 7 are input, and lead-in wire 6 and lead-in wire 5 are output, and output connects protected circuit.
Fig. 3 is the typical application circuit of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device of the present utility model.Be the utility model product in dotted line frame in figure, wherein MOV is piezoresistive wafer, and PTCR is PTC thermistor sheet, and NTCR is NTC thermistor sheet, and MOV2 is external piezoresistive element.When the input input voltage of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device assembly of the present utility model exceedes normal working voltage scope; piezo-resistance conducting; three elements all can generate heat; the PTCR mediated is except self heating power; the heat that MOV and NTCR that also can absorb both sides transmits; impel this PTCR to enter high-impedance state, cut off the current path of protected circuit end.And when voltage resume normal working voltage scope, piezo-resistance recovers high-impedance state, PTC thermistor can return to again low resistance state makes protected circuit recover normal work.When the protected circuit malfunctions of the utility model assembly causes operating current to increase above assembly non-operating current, PTC thermistor sheet enters high-impedance state and plays the cut-out function of current.Therefore the utility model assembly has over-voltage and over-current comprehensive protection function concurrently.
The pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device preparation process of the present embodiment is as follows:
By silk screen printing, solder(ing) paste is printed in the one side of piezoresistive wafer and the one side of NTC thermistor sheet; after printing, PTC thermistor sheet 2 being aimed at solder(ing) paste printed patterns is attached on piezoresistive wafer 1; the one side again NTC thermistor sheet 3 being printed with solder(ing) paste is attached on PTC thermistor sheet 2; through overbaking, piezoresistive wafer 1, PTC thermistor sheet 2 and NTC thermistor sheet 3 are connected by scolding tin; so far, the compound type overvoltage over-current protection device chip of the present embodiment has been made.At device wafer relevant position welding lead, device wafer is fixed on technique paper tape by lead-in wire, and the device wafer silicones after welding lead is encapsulated, and namely makes the pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device of the present embodiment after silicones solidification.
The present embodiment selects diameter/thickness to be about 14.0/1.9mm, pressure sensitive voltage V
1mAthe piezoresistive wafer of=390V ± 10%; Diameter/thickness is selected to be about 8.5/3.0mm; room temperature (25 DEG C) resistance 15 ~ 20 ohm; Curie temperature is the PTC thermistor sheet of 115 DEG C; diameter/thickness is selected to be about 8.5/1.8mm; the NTC thermistor sheet of room temperature (25 DEG C) resistance 45-60 ohm; make compound type overvoltage over-current protection device sample by above-mentioned execution mode, power-frequency overvoltage performance and non-operating current/overcurrent protection performance test are carried out to sample.Test result is in table 1.
Power-frequency overvoltage method of testing: power-frequency overvoltage is applied to lead-in wire 6 and lead-in wire 7 (see Fig. 1 and Fig. 2) two ends of sample, being 450VAC AC power by voltage 6 to be connected with lead-in wire 7 and going between, be energized after 30 minutes and disconnect, leave standstill 30 minutes, be energized again 30 minutes repeatedly test 10 times, after test terminates, sample appearance is unchanged, PTC thermistor sheet and NTC thermistor sheet series connection after room temperature resistance (lead-in wire 5 and lead-in wire 7 two exits between resistances) and the pressure sensitive voltage rate of change of piezoresistive wafer be all not more than ± 10%, then sample test is qualified.Because piezo-resistance has strong nonlinearity characteristic; so when applying power-frequency overvoltage between the utility model sample lead-in wire 6 and lead-in wire 7; as long as sample is not destroyed; piezo-resistance both end voltage is limited in follow-up protected circuit and can bears within voltage, thus makes protected circuit obtain overvoltage protection.
Non-operating current/overcurrent protection performance test methods: sample is placed in 70 degrees Celsius of insulating boxs, the air in insulating box relies on radiation heating, calm to reduce convective heat transfer, and sample lead-in wire 5 and lead-in wire 7 are wired to outside insulating box.By output voltage regulator (0 ~ 250V/2000W), alternating current ammeter and current-limiting resistance (500 ohm/1000 watts) and tested sample go between and 57 to be connected with going between, voltage regulator is regulated to make the electric current flowing through sample reach certain current value, maintain voltage regulator output voltage and do not change half an hour, if current value substantially constant, voltage regulator is regulated to make current value improve 5mA again, maintain voltage regulator output again not change, observe half an hour, test like this, can not be constant within half an hour until observe electric current show value, then judge that this sample non-operating current can maintain that roughly constant current value as in process of the test.Voltage regulator is exported and recalls to zero output; sample progressively cools to constant temperature the temperature inside the box; regulate voltage regulator again; ammeter is made to show current value higher than the non-operating current value 20mA recorded above; can be observed when voltage regulator maintenance output voltage is constant; ammeter show value reduces rapidly, and be reduced to 5mA in 1 minute within, visible the utility model sample has excess current protective function.
In order to contrast, made two groups of comparative sample, comparative sample 1 adopts diameter/thickness to be about 14.0/1.9mm, pressure sensitive voltage V
1mAthe piezoresistive wafer of=390V ± 10%, adopt the PTC thermistor sheet that diameter/thickness is about 8.5/4.8mm, room temperature resistance 35 ~ 45 ohm, Curie temperature are 115 DEG C, be made into piezo-resistance/PTC thermistor thermal coupling three end assembly (by document " Lu Zhenya; the Combination application of varistor and PTCR thermistor; electronic component and material; 1997.12 ", and Chinese patent 201220290529.8 discloses method), as a comparison sample 1.
Make comparative sample 2 by the same procedure of above-mentioned making comparative sample 1, the piezo-resistance diameter/thickness that comparative sample 2 adopts is about 20.0/1.9mm, pressure sensitive voltage V
1mA=390V ± 10%, the PTC thermistor sheet diameter/thickness of employing is about 13.5/3.0mm, and room temperature (25 DEG C) resistance 15 ~ 20 ohm, Curie temperature is 115 DEG C.
The utility model sample of above-mentioned making and comparative sample 1 and comparative sample 2 are carried out contrast test, and test result lists in table 1.
Table 1 sample power-frequency overvoltage, non-operating current/overcurrent characteristic test result
Test result listed by table 1, the AC voltage withstand test that the utility model sample and comparative sample 1 and comparative sample 2 can bear 450VAC is not damaged for 10 times; The volume of the utility model sample is suitable with comparative sample 1, and the non-operating current of the utility model sample is approximately 2 times of the non-operating current of comparative sample 1, and the utility model sample volume is about as much as the half of comparative sample 2 volume, but the non-operating current of the utility model sample non-operating current and comparative sample 2 is roughly the same.
Result listed by table 1 clearly shows the utility model sample and has overvoltage over-current protective feature concurrently, and, compared with prior art; equal operating current (non-operating current); device volume reduces greatly, in other words the device of equal volume, and the operating current that can bear increases greatly.
Embodiment 2
The pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device of the present embodiment except PTC thermistor sheet, NTC thermistor sheet and piezoresistive wafer are bonded together by conductive electrode material, all the other features all with embodiment 1 with.
The manufacture method of the present embodiment: silver electrode paste is attached to the one side of NTC thermistor and the one side of piezoresistive wafer by silk screen printing, the electrode diameter sizableness of printed patterns diameter and thermosensitive resistor film, after printing, the electrode slurry printed patterns aimed at by thermosensitive resistor film on piezoresistive wafer is attached on piezoresistive wafer, again the NTC thermistor sheet being printed with electrode slurry is attached on PTC resistor disc, through 150 DEG C of bakings, 550 DEG C of process, make PTC thermistor sheet, NTC thermistor sheet is connected by silver electrode with piezoresistive wafer, so far, make the compound type overvoltage over-current protection device chip of the present embodiment 2, all the other making steps are identical with embodiment 1.Described electrode slurry can adopt silver electrode paste, also can adopt aluminum electrode slurry.
The preparation process of the pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device of the present embodiment is as follows:
Silver electrode paste is attached to the one side of NTC thermistor and the one side of piezoresistive wafer by silk screen printing, the electrode diameter sizableness of printed patterns diameter and thermosensitive resistor film, after printing, the electrode slurry printed patterns aimed at by thermosensitive resistor film on piezoresistive wafer is attached on piezoresistive wafer, again the NTC thermistor sheet being printed with electrode slurry is attached on PTC resistor disc, through 150 DEG C of bakings, 550 DEG C of process, make PTC thermistor sheet, NTC thermistor sheet is connected by silver electrode with piezoresistive wafer, so far, make the compound type overvoltage over-current protection device chip of the present embodiment 2, all the other making steps are identical with embodiment 1.Described electrode slurry can adopt silver electrode paste, also can adopt aluminum electrode slurry.
Above-described embodiment is the utility model preferably execution mode; but execution mode of the present utility model is not limited by the examples; change, the modification done under other any does not deviate from Spirit Essence of the present utility model and principle, substitute, combine, simplify; all should be the substitute mode of equivalence, be included within protection range of the present utility model.
Claims (6)
1. a pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device, it is characterized in that, comprise semistor sheet, negative tempperature coefficient thermistor sheet and piezoresistive wafer, described semistor sheet, negative tempperature coefficient thermistor sheet and piezoresistive wafer are positioned at encapsulated layer; The first surface electrode of described semistor sheet is close to the first surface electrode of piezoresistive wafer and is electrically connected, and forms common port, and is drawn by the first lead-in wire; Second electrode of described semistor sheet is close to the first surface electrode of negative tempperature coefficient thermistor sheet and is electrically connected; Second electrode of described piezoresistive wafer is drawn by the second lead-in wire; Second electrode of described negative tempperature coefficient thermistor sheet is drawn by the 3rd lead-in wire; Described second lead-in wire and the 3rd lead-in wire are input, and the first lead-in wire and the second lead-in wire are output, and output connects protected circuit.
2. pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device according to claim 1, it is characterized in that, the first surface electrode of described semistor sheet is connected by soldering-tin layer with the first surface electrode of piezoresistive wafer.
3. pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device according to claim 1, is characterized in that, the first surface electrode of described semistor sheet is bonding by conductive electrode slurry with the first surface electrode of piezoresistive wafer.
4. pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device according to claim 1, is characterized in that, second electrode of described semistor sheet is connected by soldering-tin layer with the first surface electrode of negative tempperature coefficient thermistor sheet.
5. pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device according to claim 1, is characterized in that, second electrode of described semistor sheet is bonding by conductive electrode slurry with the first surface electrode of negative tempperature coefficient thermistor sheet.
6. pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device according to claim 1, it is characterized in that, described encapsulated layer is silicones encapsulated layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420626390.9U CN204205546U (en) | 2014-10-27 | 2014-10-27 | A kind of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420626390.9U CN204205546U (en) | 2014-10-27 | 2014-10-27 | A kind of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device |
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| CN204205546U true CN204205546U (en) | 2015-03-11 |
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| CN201420626390.9U Expired - Fee Related CN204205546U (en) | 2014-10-27 | 2014-10-27 | A kind of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104332944A (en) * | 2014-10-27 | 2015-02-04 | 华南理工大学 | Pressure-sensitive and thermosensitive combined type overvoltage and over-current protecting device |
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2014
- 2014-10-27 CN CN201420626390.9U patent/CN204205546U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104332944A (en) * | 2014-10-27 | 2015-02-04 | 华南理工大学 | Pressure-sensitive and thermosensitive combined type overvoltage and over-current protecting device |
| CN104332944B (en) * | 2014-10-27 | 2017-10-20 | 华南理工大学 | A kind of pressure-sensitive temperature-sensitive compound type overvoltage over-current protection device |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150311 Termination date: 20191027 |