CN2362177Y - Self-protecting piezo-resistance for overvoltage protection - Google Patents
Self-protecting piezo-resistance for overvoltage protection Download PDFInfo
- Publication number
- CN2362177Y CN2362177Y CN 99234354 CN99234354U CN2362177Y CN 2362177 Y CN2362177 Y CN 2362177Y CN 99234354 CN99234354 CN 99234354 CN 99234354 U CN99234354 U CN 99234354U CN 2362177 Y CN2362177 Y CN 2362177Y
- Authority
- CN
- China
- Prior art keywords
- resistance
- piezo
- resistor
- self
- utility
- 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.)
- Expired - Fee Related
Links
Images
Abstract
The utility model relates to a self-protecting resistor for overvoltage protection. The utility model is a composite resistor which is formed by a zinc oxide pressure responsive resistor and a positive temperature coefficient lagged type thermosensitive resistor which are connected in series. The utility model utilizes the characteristic that the resistance value of the thermosensitive resistor is varied following the temperature to limit the flux of current of the composite resistor when surge voltage is too high or duration time is longer, which can prevent an electric network from a short circuit, and simultaneously can enhance the capacity for resisting over pressure for the pressure responsive resistor. Through the improvement, the composite resistor has a function for preventing an electric network from a short circuit, a protector pipe can be cancelled, and the composite resistor has a self-protecting function.
Description
The utility model is a kind of self-shield type resistance that is used for overvoltage protection.
In order to prevent in the electrical network surge voltage to the infringement of electronics or electric equipment, all be connected to a zinc oxide varistor Rz (hereinafter to be referred as piezo-resistance) usually at the power end of existing electronics, electric equipment, its equivalent electric circuit is as shown in Figure 3.This piezo-resistance is a voltage-sensitive device, has the voltage-current characteristic that its electric current sharply increases with the increase of applying voltage, and its curve as shown in Figure 4.The overvoltage protection principle of piezo-resistance is referring to Fig. 5, and when occurring surge voltage VS in the electrical network, the voltage at piezo-resistance two ends surpasses the pressure sensitive voltage V of the piezo-resistance that sets
1MA, at this moment, the current flux of piezo-resistance sharply increases, and the voltage Vz at piezo-resistance two ends is lower than the withstand voltage level V0 of protected equipment.Like this, be equivalent to surge voltage and absorbed, make equipment exempt from the attack of surge voltage by piezo-resistance.But if surge voltage is too high or the duration is long, piezo-resistance is with regard to having breakdown and to the danger of grid short circuit.For fear of the generation of this situation, common protective tube F of serial connection in circuit, it is breakdown in piezo-resistance and moment complete conducting fuses, thereby avoids the short circuit to electrical network.Though this protective tube can play the effect that prevents grid short circuit, it does not improve the ability of the anti-lasting surge voltage of piezo-resistance, makes piezo-resistance still damage easily under the lasting impact of surge voltage.
The purpose of this utility model is at the low shortcoming of the anti-lasting surge voltage ability of piezo-resistance, and a kind of self-shield type piezo-resistance is provided, thereby improves the performance of piezo-resistance overvoltage protection.
For achieving the above object, solution of the present utility model is as follows: it is a combined resistance that is made of Zinc-oxide piezoresistor and the series connection of positive temperature coefficient delaying type thermistor.
By above-mentioned solution as can be seen, the utility model has replaced single piezo-resistance with combined resistance.Positive temperature coefficient delaying type thermistor (hereinafter to be referred as thermistor) in this combined resistance is a temperature sensor, and it has the characteristic that its resistance value suddenly increases with the temperature rising.The utility model utilizes this characteristic, in surge voltage under the too high or longer situation of duration, thermistor presents high value because of self flowing through its fervescence of bigger surge current, thereby limited the current flux of combined resistance, prevented short circuit to electrical network, simultaneously, also strengthened the anti-overvoltage capabilities of piezo-resistance.Through after improving, this combined resistance not only self has possessed the function that prevents grid short circuit, can omit protective tube, but also has had the function of autoprotection.
Describe operation principle of the present utility model in detail according to embodiment below.
Fig. 1, equivalent circuit theory figure of the present utility model.
Fig. 2, the temperature variant curve chart of thermistor resistance.
The equivalent circuit theory figure of Fig. 3, prior art.
The volt-ampere characteristic figure of Fig. 4, piezo-resistance.
The curve chart of Fig. 5, piezo-resistance overvoltage protection principle.
Referring to Fig. 1; described self-shield type piezo-resistance is an independently combined resistance 1 that is made of Zinc-oxide piezoresistor Rz and positive temperature coefficient delaying type thermistor Rt series connection, and it can be used to replace piezo-resistance single in the prior art and the power end that is attempted by protected equipment 2.It can limit switching overvoltage, lightning overvoltage, spike overvoltage, can also the residual amount of energy of energy storage device in the equipment be absorbed, and makes equipment exempt from superpotential harm.
Selection of parameter to described combined resistance is further described below.The selection of parameter of combined resistance mainly is to determine the pressure sensitive voltage V of piezo-resistance
1MA(being the leakage current of the piezo-resistance voltage that its two ends are applied when being 1MA) and thermistor arrive the required time ts of switch temperature.The pressure sensitive voltage value V of piezo-resistance
1MAThe operation voltage that is equivalent to piezo-resistance, as can be seen, when the voltage that is applied when the piezo-resistance two ends surpassed pressure sensitive voltage, the electric current of piezo-resistance can sharply increase from the curve of Fig. 4; Otherwise the electric current of piezo-resistance is equivalent to turn-off less than 1MA.The switch temperature TB of thermistor is the operating temperature of thermistor, from the curve of Fig. 2 as can be seen, when the body temperature of thermistor reaches its switch temperature TB, its resistance can suddenly rise and present high value, determines that by the big I of choosing this switch temperature thermistor arrives the required time ts of this switch temperature.According to Fig. 5, if the pressure sensitive voltage V of piezo-resistance
1MAProof voltage level V0 less than protected equipment; then when occurring surge voltage Vs in the electrical network; the piezo-resistance conducting; and this moment, thermistor was in the normal temperature low resistance state; then the current flux of combined resistance increases; make combined resistance both end voltage Vz be lower than the proof voltage level V0 of protected equipment, thereby avoided the harm of overvoltage equipment.When higher or duration is long relatively when surge voltage, the electric current that flows through thermistor is bigger, the body temperature of thermistor is risen, reach its switch temperature TB very soon, then the resistance of thermistor raises immediately, thereby limited the current flux of piezo-resistance, avoided it to be in complete conducting state, prevented short circuit electrical network; Simultaneously; the time ts that thermistor is arrived its switch temperature is limited within the time t0 (given in the user's manual of piezo-resistance) of the piezo-resistance energy of anti-the overvoltage; can play a protective role to piezo-resistance; increased the automatic recovery ability of piezo-resistance, the ability of the anti-sustained overvoltage of piezo-resistance is strengthened.Show through shock-resistant experiment: the ability of the anti-sustained overvoltage of combined resistance is apparently higher than single piezo-resistance.Other selection of parameter of piezo-resistance and thermistor is determined according to the proof voltage ability and the specification in the user's manual of protected equipment.
Claims (2)
1, a kind of self-shield type piezo-resistance that is used for overvoltage protection is characterized in that: it is a combined resistance that is made of Zinc-oxide piezoresistor and the series connection of positive temperature coefficient delaying type thermistor.
2, self-shield type varistor as claimed in claim 1 is characterized in that: the pressure sensitive voltage V of described Zinc-oxide piezoresistor
1MABe lower than the withstand voltage V0 of protected equipment, described positive temperature coefficient delaying type thermistor arrives the time t0 of the time ts of switch temperature less than the piezo-resistance energy of anti-the overvoltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99234354 CN2362177Y (en) | 1999-01-26 | 1999-01-26 | Self-protecting piezo-resistance for overvoltage protection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99234354 CN2362177Y (en) | 1999-01-26 | 1999-01-26 | Self-protecting piezo-resistance for overvoltage protection |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2362177Y true CN2362177Y (en) | 2000-02-02 |
Family
ID=34022537
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 99234354 Expired - Fee Related CN2362177Y (en) | 1999-01-26 | 1999-01-26 | Self-protecting piezo-resistance for overvoltage protection |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2362177Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104392871A (en) * | 2014-11-14 | 2015-03-04 | 华南理工大学 | Residual-current circuit breaker with overvoltage protection function |
-
1999
- 1999-01-26 CN CN 99234354 patent/CN2362177Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104392871A (en) * | 2014-11-14 | 2015-03-04 | 华南理工大学 | Residual-current circuit breaker with overvoltage protection function |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102035188B (en) | Novel thyristor overvoltage protection method | |
| CN106786459B (en) | Surge protection circuit and electronic device using same | |
| WO2002091398A3 (en) | Circuit protection arrangement | |
| CN202282601U (en) | Protection circuit combining high-polymer phenylthiocarbamide (PTC) thermistor and piezoresistor | |
| CN202268694U (en) | Lightning surge protection circuit applied to digital microwave transceiver | |
| CN2362177Y (en) | Self-protecting piezo-resistance for overvoltage protection | |
| CN102403710A (en) | Thermistor type overvoltage/overcurrent protection circuit | |
| CN202949205U (en) | Lightning arrester overvoltage protection device with variable voltage ratio | |
| CN201118225Y (en) | Primary current limiting resonance eliminating device | |
| CN103311916B (en) | Thunder-prevention overvoltage protection device | |
| CN209642317U (en) | A kind of pcb board load formula surge protector | |
| CN100452609C (en) | Over voltage breaking protector | |
| CN102403707A (en) | Double-thermistor self-protective overvoltage/overcurrent protection circuit | |
| CN205104900U (en) | Overvoltage/overcurrent protection circuit | |
| CN2335293Y (en) | Self-recovery indicating type protector | |
| CN2101960U (en) | Over-pressure automatic protector for domestic electric appliance | |
| CN203289096U (en) | Overvoltage protective circuit for composite piezoresistor | |
| CN204992522U (en) | Circuit protector | |
| CN102412572A (en) | Temperature switch type over-voltage protection circuit | |
| CN220692824U (en) | Surge protection circuit with low leakage current and long service life | |
| CN204089182U (en) | Self-recoverage over-voltage over-current protection device | |
| CN220234201U (en) | Lightning protection circuit and power supply system | |
| CN209266748U (en) | Intelligent temperature control socket | |
| CN2229102Y (en) | Voltage-sensitive resistor | |
| CN219477835U (en) | Rectifier |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |