CN102403711A - Resettable fuse type self protection overvoltage overcurrent protection circuit - Google Patents
Resettable fuse type self protection overvoltage overcurrent protection circuit Download PDFInfo
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- CN102403711A CN102403711A CN2011103636477A CN201110363647A CN102403711A CN 102403711 A CN102403711 A CN 102403711A CN 2011103636477 A CN2011103636477 A CN 2011103636477A CN 201110363647 A CN201110363647 A CN 201110363647A CN 102403711 A CN102403711 A CN 102403711A
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- resettable fuse
- protection
- resistance
- circuit
- voltage sensitive
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Abstract
The invention relates to a resettable fuse type self protection overvoltage overcurrent protection circuit, which comprises a voltage sensitive resistor, a ceramic PTC thermal sensitive resistor, a resettable fuse and a protected circuit; the resettable fuse is connected in series with the protected circuit and then is connected in parallel with a resistor formed in a manner that the voltage sensitive resistor is connected in series with the ceramic PTC thermal sensitive resistor; and the voltage sensitive resistor and the resettable fuse have a common connecting end. The technical scheme has the effects that: the reliability of the zinc oxide voltage sensitive resistor is improved and the voltage sensitive failure caused by longtime overvoltage is avoided; the problem on the voltage sensitive failure caused by too slow protection of the resettable fuse on the conventional overvoltage overcurrent protection device is solved; and the defect on too slow protection and even non protection of the resettable fuse on the conventional overvoltage overcurrent protection device in low temperature environment is solved.
Description
Technical field
The present technique scheme belongs to the electronic circuit technology field, specifically is a kind of resettable fuse type self-shield type over-voltage over-current protection circuit.
Background technology
Zinc-oxide piezoresistor has nonlinear voltage-current characteristic; Generally be used for electronic circuit and do anti-overvoltage, anti-thunderbolt protector spare; Its operation principle is that varistor is connected on the protected circuit, and when line voltage distribution was lower than the operational voltage value of piezo-resistance, the varistor resistance was high; Be close to open circuit, thereby can not influence the operate as normal of device or electric equipment.When voltage instantaneous was higher than a certain numerical value, the varistor resistance descended rapidly, the big electric current of conducting, thereby with voltage clamp protection protected device or electric equipment in the voltage range that protected device or electric equipment can bear.Zinc-oxide piezoresistor absorbs energy when conducting, self temperature raises rapidly, so absorbent energy is limited during the piezo-resistance conducting, causes the piezo-resistance temperature too high and thermal breakdown was lost efficacy if energy is crossed senior general.
Summary of the invention
In order to solve the problems referred to above that exist in the prior art, the present technique scheme proposes a kind of self-shield type over-voltage over-current protection circuit and device, and concrete technical scheme is following:
A kind of resettable fuse type self-shield type over-voltage over-current protection circuit comprises piezo-resistance, ceramic PTC thermistor, resettable fuse and by protective circuit; Said resettable fuse and be connected in series by protective circuit after, be connected in parallel with said piezo-resistance and the ceramic PTC thermistor resistance that constitutes that is connected in series again; Said piezo-resistance and resettable fuse have common link.
The principle of present technique scheme is following:
Pottery PTC thermistor has nonlinear resistivity-temperature characteristics, and its resistance raises with the rising of temperature, has high withstand voltagely, and the ageing, and anti performance is the excellent components and parts of overtemperature protection.
Resettable fuse is by forming through the polymer resin (Polymer) of special processing and the conducting particles (Carbon Black) that is distributed in the inside.Polymer resin closely is strapped in conducting particles outside the crystalloid structure under normal operation; Constitute chain conduction electric pathway; The resettable fuse of this moment is a low resistive state, and the heat energy that electric current produced of the self-healing fuse of flowing through on the circuit is little, can not change crystal structure.When circuit was short-circuited or transship, the heat that the big electric current of the self-healing fuse of flowing through produces melted polymer resin, and volume increases rapidly, forms high-impedance state, and operating current reduces rapidly, thereby circuit is limited and protects.After fault was got rid of, self-healing fuse is crystallisation by cooling again, volume contraction, and conducting particles forms conductive path again, and self-healing fuse reverts to low resistive state, thereby accomplishes the protection to circuit, need not artificially change.
The operation principle of this technical scheme is: pressure sensitive voltage conducting when line voltage distribution surpasses the conducting voltage of piezo-resistance; Temperature raises rapidly and passes to ceramic PTC thermistor 2; Pottery PTC thermistor 2 protects piezo-resistance to avoid because of long-time overvoltage thermal breakdown because of temperature rising resistance increases rapidly; Meanwhile resettable fuse 3 also raises because of temperature and the self-heating temperature that ceramic PTC thermistor 2 and piezo-resistance are transmitted; Its resistance increases rapidly and protects by protective circuit, reaches the effect of overvoltage protection.The PTC thermistor reaches the effect of overcurrent protection because of the characteristic that himself has overcurrent protection when overcurrent condition appears in circuit.
The effect of present technique scheme is following:
1, improves the reliability of Zinc-oxide piezoresistor, avoid causing pressure-sensitive inefficacy because of long-time overvoltage.
2, solve conventional over-voltage and over-current protector spare and protected the situation that causes pressure-sensitive inefficacy slowly because of resettable fuse.
3, solve resettable fuse and under low temperature environment, protected the slow not even defective of protection.
Description of drawings
Fig. 1 is a self-shield type over-voltage over-current protection circuit sketch map;
Among the figure, piezo-resistance 1, ceramic PTC thermistor 2, resettable fuse 3.
Embodiment
Below in conjunction with accompanying drawing and embodiment the present technique scheme is further specified as follows:
A kind of resettable fuse type self-shield type over-voltage over-current protection circuit comprises piezo-resistance, ceramic PTC thermistor, resettable fuse and by protective circuit; Said resettable fuse and be connected in series by protective circuit after, be connected in parallel with said piezo-resistance and the ceramic PTC thermistor resistance that constitutes that is connected in series again; Said piezo-resistance and resettable fuse have common link.
Claims (1)
1. resettable fuse type self-shield type over-voltage over-current protection circuit is characterized in that comprising piezo-resistance, ceramic PTC thermistor, resettable fuse and by protective circuit; Said resettable fuse and be connected in series by protective circuit after, be connected in parallel with said piezo-resistance and the ceramic PTC thermistor resistance that constitutes that is connected in series again; Said piezo-resistance and resettable fuse have common link.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103636477A CN102403711A (en) | 2011-11-17 | 2011-11-17 | Resettable fuse type self protection overvoltage overcurrent protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103636477A CN102403711A (en) | 2011-11-17 | 2011-11-17 | Resettable fuse type self protection overvoltage overcurrent protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102403711A true CN102403711A (en) | 2012-04-04 |
Family
ID=45885630
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011103636477A Pending CN102403711A (en) | 2011-11-17 | 2011-11-17 | Resettable fuse type self protection overvoltage overcurrent protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102403711A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103457251A (en) * | 2013-08-30 | 2013-12-18 | 武汉联创恒业科技有限公司 | Protective circuit based on PTC thermistor |
| CN104934954A (en) * | 2014-03-17 | 2015-09-23 | 斯玛特电子公司 | Fuse resistor |
| CN106684811A (en) * | 2016-10-31 | 2017-05-17 | 广西大学 | Anti-overcurrent device |
| CN110336264A (en) * | 2019-08-22 | 2019-10-15 | 成都铁达电子股份有限公司 | A kind of pressure limiting circuit |
-
2011
- 2011-11-17 CN CN2011103636477A patent/CN102403711A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103457251A (en) * | 2013-08-30 | 2013-12-18 | 武汉联创恒业科技有限公司 | Protective circuit based on PTC thermistor |
| CN104934954A (en) * | 2014-03-17 | 2015-09-23 | 斯玛特电子公司 | Fuse resistor |
| CN104934954B (en) * | 2014-03-17 | 2018-10-09 | 斯玛特电子公司 | Fuse-resistor |
| CN106684811A (en) * | 2016-10-31 | 2017-05-17 | 广西大学 | Anti-overcurrent device |
| CN110336264A (en) * | 2019-08-22 | 2019-10-15 | 成都铁达电子股份有限公司 | A kind of pressure limiting circuit |
| CN110336264B (en) * | 2019-08-22 | 2024-01-26 | 成都铁达电子股份有限公司 | Voltage limiting circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20120404 |