CN102403707A - Double-thermistor self-protective overvoltage/overcurrent protection circuit - Google Patents
Double-thermistor self-protective overvoltage/overcurrent protection circuit Download PDFInfo
- Publication number
- CN102403707A CN102403707A CN2011103615894A CN201110361589A CN102403707A CN 102403707 A CN102403707 A CN 102403707A CN 2011103615894 A CN2011103615894 A CN 2011103615894A CN 201110361589 A CN201110361589 A CN 201110361589A CN 102403707 A CN102403707 A CN 102403707A
- Authority
- CN
- China
- Prior art keywords
- thermistor
- ceramic ptc
- ptc thermistor
- overvoltage
- overcurrent protection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000000919 ceramic Substances 0.000 claims abstract description 24
- 230000001681 protective effect Effects 0.000 claims description 9
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 abstract description 8
- 239000011787 zinc oxide Substances 0.000 abstract description 4
- 230000007774 longterm Effects 0.000 abstract 1
- 238000000034 method Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 229960001296 zinc oxide Drugs 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 2
- 230000001012 protector Effects 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 230000002745 absorbent Effects 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
Images
Landscapes
- Thermistors And Varistors (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
A double-thermistor self-protective overvoltage/overcurrent protection circuit comprises a piezoresistor, a first ceramic PTC (Positive Temperature Coefficient) thermistor, a second ceramic PTC thermistor and a protected circuit, wherein the piezoresistor is connected in series with the first ceramic PTC thermistor and then connected in parallel with the protected circuit, and finally connected in series with the second ceramic PTC thermistor. The technical proposal is capable of improving the reliability of the zinc oxide piezoresistor and avoiding voltage-sensitive effectiveness loss due to long-term overvoltage; therefore, the problem of the voltage-sensitive effectiveness loss of the conventional overvoltage/overcurrent protection device due to too slow protection of the thermistor is solved.
Description
Technical field
The present technique scheme belongs to the electronic circuit technology field, specifically is a kind of pair of thermistor 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 pair of thermistor self-shield type over-voltage over-current protection circuit is characterized in that comprising piezo-resistance, the first ceramic PTC thermistor, the second ceramic PTC thermistor and by protective circuit; The said piezo-resistance and the first ceramic PTC thermistor are connected in series, and are connected in parallel again with by protective circuit, and the last and second ceramic PTC thermistor is connected in series.
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.Simultaneously ceramic PTC thermistor also is widely used in and substitutes traditional Fuse Type fuse in the various electronic circuits and do overcurrent, overload protection.Its operation principle is: when circuit was in normal condition, the electric current through ceramic PTC thermistor was less than rated current, and the PTC thermistor is in the normal state, and resistance is very little, can not influence by the operate as normal of protective circuit.When circuit breaks down, when electric current substantially exceeded rated current, the PTC thermistor suddenly generated heat, and is high-impedance state, make circuit be in relatively " disconnection " state, thereby protective circuit was not damaged.After fault was got rid of, overcurrent protection also automatically returned to low resistance state with the PTC thermistor, and circuit recovers operate as normal.
This technical scheme operation principle is: pressure sensitive voltage conducting when line voltage distribution surpasses the conducting voltage of piezo-resistance; Temperature raises rapidly and passes to the first ceramic PTC thermistor 2; The first ceramic PTC thermistor 2 protects piezo-resistance to avoid because of long-time overvoltage thermal breakdown because of temperature rising resistance increases rapidly; Meanwhile the second ceramic PTC thermistor 3 also raises because of temperature and the self-heating temperature that the first 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 thermistor.
Description of drawings
Fig. 1 is a self-shield type over-voltage over-current protection circuit structural representation;
Among the figure, piezo-resistance 1, first ceramic PTC thermistor 2, the second ceramic PTC thermistor 3.
Embodiment
Below in conjunction with accompanying drawing and embodiment the present technique scheme is further specified as follows:
A kind of self-shield type over-voltage over-current protection circuit comprises piezo-resistance, the first ceramic PTC thermistor, the second ceramic PTC thermistor and by protective circuit; The said piezo-resistance and the first ceramic PTC thermistor are connected in series, and are connected in parallel again with by protective circuit, and the last and second ceramic PTC thermistor is connected in series.
Claims (1)
1. two thermistor self-shield type over-voltage over-current protection circuit is characterized in that comprising piezo-resistance, the first ceramic PTC thermistor, the second ceramic PTC thermistor and by protective circuit; The said piezo-resistance and the first ceramic PTC thermistor are connected in series, and are connected in parallel again with by protective circuit, and the last and second ceramic PTC thermistor is connected in series.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103615894A CN102403707A (en) | 2011-11-16 | 2011-11-16 | Double-thermistor self-protective overvoltage/overcurrent protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103615894A CN102403707A (en) | 2011-11-16 | 2011-11-16 | Double-thermistor self-protective overvoltage/overcurrent protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102403707A true CN102403707A (en) | 2012-04-04 |
Family
ID=45885626
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011103615894A Pending CN102403707A (en) | 2011-11-16 | 2011-11-16 | Double-thermistor self-protective overvoltage/overcurrent protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102403707A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105098742A (en) * | 2014-04-29 | 2015-11-25 | 瑞侃电子(上海)有限公司 | Current balance control unit, electric appliance part, electric appliance component and circuit |
| 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
- 2011-11-16 CN CN2011103615894A patent/CN102403707A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105098742A (en) * | 2014-04-29 | 2015-11-25 | 瑞侃电子(上海)有限公司 | Current balance control unit, electric appliance part, electric appliance component and circuit |
| 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 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102522736A (en) | Self-protecting type over-voltage and over-current protective device with double thermistors | |
| CN103311914B (en) | Overvoltage production circuit of composite type piezoresistor | |
| CN103457251A (en) | Protective circuit based on PTC thermistor | |
| CN102751707A (en) | Overcurrent and overvoltage protector with bimetallic strip temperature switch | |
| CN202282601U (en) | Protection circuit combining high-polymer phenylthiocarbamide (PTC) thermistor and piezoresistor | |
| CN202206131U (en) | Current-limiting type double-channel surge protection device | |
| CN203039363U (en) | Three-phase surge protector | |
| CN102403711A (en) | Resettable fuse type self protection overvoltage overcurrent protection circuit | |
| CN102403705A (en) | Thermistor type over-current and over-voltage protection device | |
| CN202797931U (en) | Power lightning arrester for overvoltage protection device | |
| CN202678007U (en) | Varistor with self-protection function | |
| CN102403710A (en) | Thermistor type overvoltage/overcurrent protection circuit | |
| CN102403704A (en) | Overcurrent overvoltage protection device | |
| CN102403707A (en) | Double-thermistor self-protective overvoltage/overcurrent protection circuit | |
| CN102403706A (en) | Resettable fuse type self-protective overvoltage/overcurrent protection device | |
| CN103094890A (en) | Flexible limited current circuit | |
| CN204204542U (en) | There is the temperature-sensitive device of over-voltage protecting function, protective circuit and electronic equipment | |
| CN201111299Y (en) | Composite type excessive heating protective resistor | |
| CN218386806U (en) | Circuit protection device | |
| CN203434386U (en) | Safety socket with over current protection function | |
| CN203014373U (en) | Transient surge protector used specially for elevator | |
| CN102545144A (en) | Temperature switch type overvoltage protection device | |
| CN202978261U (en) | Double-channel surge protector | |
| CN102412572A (en) | Temperature switch type over-voltage protection circuit | |
| CN102437562A (en) | Resettable fuse type overvoltage and overcurrent protection circuit |
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 |