CN104953539A - Low-voltage-side overvoltage protection circuit - Google Patents
Low-voltage-side overvoltage protection circuit Download PDFInfo
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- CN104953539A CN104953539A CN201410115497.1A CN201410115497A CN104953539A CN 104953539 A CN104953539 A CN 104953539A CN 201410115497 A CN201410115497 A CN 201410115497A CN 104953539 A CN104953539 A CN 104953539A
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Abstract
The invention discloses a low-voltage-side overvoltage protection circuit. The low-voltage-side overvoltage protection circuit includes a switch tube, a first control circuit and a second control circuit. The output terminal of the second control circuit is connected to the input terminal of the first control circuit. The output terminal of the first control circuit is connected with a base electrode of the switch tube. A collector electrode of the switch tube is connected to output voltage. A transmitting electrode of the switch tube, the first control circuit and the second control circuit are connected to input voltage separately. The low-voltage-side overvoltage protection circuit can work under comparatively low voltage and does not need protection from a large number of composite PTCs. The protection real time performance is high and the universality is good. By adopting the circuit provided by the invention, a load on the rear end of the output voltage can be controlled accurately in real time so as to avoid damage and a protection function can be realized through quick circulation control when low input voltage is over range.
Description
Technical field
The present invention relates to electric power monitoring field, particularly, relate to a kind of low-pressure side overvoltage crowbar.
Background technology
Along with the more and more intellectuality of power industry, the installation of a large amount of electric energy efficiency monitoring terminals, three-phase and four-line ammeter and power information acquisition terminal and utilization, scene also there will be phase line to the installation of watt-hour meter device and zero line connects anti-situation.The intelligent electric meter of tackling with it that yes of arising at the historic moment connects the protection of anti-situation to phase line and zero line, be also referred to as the protection of the input voltage of 1.9 times of UN.
Prior art is divided into three kinds of schemes, and a kind of scheme uses PTC thermistor to do overvoltage to take precautions against; One does not use thermistor, utilizes that the magnetic saturation electric current of transformer is less resists 4 hours firmly when 1.9 times of overvoltage; The third scheme uses a kind of novel compound PTC, and it is the compound PTC be packaged together by a kind of special process by a semistor and a Zinc-oxide piezoresistor.
Along with the further raising of future electrical energy industry requirement, require that instrument is under 220 ± 50% wide-voltage ranges, still can normally measure under 1.9 times of overvoltage conditions to become the common trend of this industry.
Use PTC thermistor overvoltage to take precautions against in the first scheme, can not be competent at development and the performance of existing ammeter technology completely, easily occur problems.As: PTC normal temperature low temperature is not protected, high temperature protection by mistake; Difficulty is mated with transformer; Ammeter cisco unity malfunction etc. after overvoltage condition protection.When using transformer firmly to resist 1.9 times of overvoltages in first scheme, increase the weight of the burden of transformer and rear class components and parts, ammeter also can have been caused at the lower voltage not work on the other hand.Use novel compound PTC in the third scheme, although be a kind of New Products, and versatility is very good, and each three-phase and four-line instrument will mate 3 compound PTC thermistor, expensive and usage quantity is numerous.
Summary of the invention
The present invention takes precautions against the problem of poor reliability to overcome PTC thermistor overvoltage in prior art, according to an aspect of the present invention, proposes a kind of low-pressure side overvoltage crowbar.
According to low-pressure side overvoltage crowbar of the present invention, comprising:
Switching tube, first control circuit, second control circuit, the output of second control circuit is connected with the input of first control circuit, and the output of first control circuit is connected with the base stage of switching tube, and output voltage connected by the collector electrode of switching tube; The emitter of switching tube, first control circuit, second control circuit connect input voltage respectively;
Second control circuit comprises: the first divider resistance, the second divider resistance, the first current-limiting resistance, pull down resistor, conducting diode, the first triode, input voltage is connected in one end of first divider resistance, the other end of the first divider resistance is connected with one end of the second divider resistance, the other end ground connection of the second divider resistance; First divider resistance, the common port of the second divider resistance are connected with the negative pole of conducting diode;
One end of pull down resistor is connected with the input of the first triode, and the other end of pull down resistor is connected to the ground; The positive pole of conducting diode is connected by the first current-limiting resistance with the common port of pull down resistor, described first triode; The output of the first triode is connected with the input of first control circuit.
Low-pressure side overvoltage crowbar of the present invention; also can normally work at the lower voltage; the compound PTC not needing usage quantity numerous protects; protection real-time is fast; highly versatile; the load that can be control output voltage rear end by the present invention in real time is accurately not damaged; as long as there is fluctuation change in front end input voltage; second control circuit controls first control circuit; first control circuit controls switching tube, and loop control rapidly can reach the defencive function when low pressure input voltage over range.
Other features and advantages of the present invention will be set forth in the following description, and, partly become apparent from specification, or understand by implementing the present invention.Object of the present invention and other advantages realize by structure specifically noted in write specification, claims and accompanying drawing and obtain.
Below by drawings and Examples, technical scheme of the present invention is described in further detail.
Accompanying drawing explanation
Accompanying drawing is used to provide a further understanding of the present invention, and forms a part for specification, together with embodiments of the present invention for explaining the present invention, is not construed as limiting the invention.In the accompanying drawings:
Fig. 1 is the structural representation of low-pressure side overvoltage crowbar of the present invention;
Fig. 2 is the circuit theory diagrams of low-pressure side overvoltage crowbar of the present invention;
Fig. 3 is the circuit theory diagrams of first control circuit of the present invention;
Fig. 4 is the circuit theory diagrams of second control circuit of the present invention;
Fig. 5 is the low-pressure side overvoltage crowbar circuit theory diagrams of the specific embodiment of the invention;
Fig. 6 is the circuit theory diagrams of the first control circuit of the specific embodiment of the invention;
Fig. 7 is the circuit theory diagrams of the second control circuit of the specific embodiment of the invention.
Embodiment
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in detail, but is to be understood that protection scope of the present invention not by the restriction of embodiment.
According to the embodiment of the present invention, provide a kind of low-pressure side overvoltage crowbar, to solve the problem that poor reliability is taken precautions against in the PTC thermistor overvoltage existed in prior art.
According to the low-pressure side overvoltage crowbar of the embodiment of the present invention; as Figure 1-Figure 2; comprise: switching tube V20, first control circuit 40, second control circuit 50; the output of second control circuit 50 is connected with the input of first control circuit 40; the output of first control circuit 40 is connected with the base stage of switching tube V20; the emitter of switching tube V20, first control circuit 40, second control circuit 50 connect input voltage U10 respectively, and output voltage U30 connected by the collector electrode of switching tube V20.
In the low-pressure side overvoltage crowbar of the embodiment of the present invention, can also comprise electric capacity C60, the collector electrode of switching tube V20 is connected with the positive pole of electric capacity C60, the minus earth of electric capacity C60.
DC low-voltage input voltage U10 arrives DC low-voltage output voltage U30 through switching tube V20, switching tube V20 is control conducting or cut-off by first control circuit 40, the enable of first control circuit 40 is controlled by second control circuit 50, and first control circuit 40 and second control circuit 50 are all as input voltage by low-voltage direct input voltage U10.In the present invention, only have when first control circuit 40 conducting, switching tube V20 conducting; When first control circuit 40 ends, V20 also ends.
Input voltage U10 is DC low-voltage input, and switching tube V20 is triode, when input voltage U10 is within the scope of normal setting voltage, and first control circuit 40 conducting, switching tube V20 conducting; When input voltage U10 is higher than normal setting voltage scope maximum, second control circuit 50 conducting, second control circuit 50 controls first control circuit 40 to be ended, and switching tube V20 ends; When input voltage U10 is less than normal setting voltage stated range minimum, first control circuit 40, second control circuit 50, switching tube V20 all end.
Above-mentioned normal setting voltage scope is the circuit voltage scope of output voltage U30 rear end, and circuit working principle of the present invention is described as follows:
As shown in Figure 3, first control circuit 40 comprises: the 3rd divider resistance R401, the 4th divider resistance R402, the second current-limiting resistance R403, the second triode V404, the 3rd current-limiting resistance R405, input voltage U10 is connected in one end of 3rd divider resistance R401, the other end of the 3rd divider resistance R401 is connected with one end of the 4th divider resistance R402, the other end ground connection of the 4th divider resistance R402; The common port of the 3rd divider resistance R401, the 4th divider resistance R402 is connected by the second current-limiting resistance R403 with the input of the second triode V404, and the common port of the second current-limiting resistance R403, the second triode V404 is connected with the output of the first triode V506; The output of the second triode V404 is connected by the 3rd current-limiting resistance R405 with the base stage of switching tube V20, and the 3rd current-limiting resistance R405 is made up of multiple resistor coupled in parallel, to share power, avoids that power is excessive burns out resistance.In embodiments of the present invention, the base stage of the second triode V404 is input, and current collection is output very, the grounded emitter of the second triode V404.
The cut-in voltage of the second triode V404 is about 0.7V, when flowing through V404 input terminal voltage and being greater than 0.7V, and V404 conducting, when the input terminal voltage flowing through V404 is less than 0.7V, V404 ends, wherein this input terminal voltage=R402/(R401+R402) * U10.The emitter of switching tube V20 connects input voltage U10, and the collector electrode of switching tube V20 connects output voltage U30 by the positive pole of electric capacity, and the minus earth of this electric capacity, the base stage of switching tube V20 is connected with the 3rd current-limiting resistance R405.
As shown in Figure 4, second control circuit 50 comprises: the first divider resistance R501, the second divider resistance R502, the first current-limiting resistance R503, pull down resistor R504, conducting diode D505, the first triode V506, input voltage U10 is connected in one end of first divider resistance R501, the other end of the first divider resistance R501 is connected with one end of the second divider resistance R502, and the other end of the second divider resistance R502 is connected to the ground; The common port of the first divider resistance R501, the second divider resistance R502 is connected with the negative pole of conducting diode D505; One end of pull down resistor R504 is connected with the input of the first triode V506, and the positive pole of conducting diode D505 is connected by the first current-limiting resistance R503 with the common port of pull down resistor R504, the first triode V506; The other end of pull down resistor R504 is connected to the ground; The output of the first triode V506 is connected with first control circuit 40.In embodiments of the present invention, the base stage of the first triode V506 is input, and current collection is output very, and the emitter of the first triode V506 is connected to the ground.
Conducting diode D505 is voltage stabilizing didoe, conducting diode D505 is equivalent to the switch of second control circuit 50 inside, conducting diode D505 has conducting voltage parameter, when the voltage flowing through conducting diode D505 negative pole is greater than this conducting voltage parameter, and conducting diode D505 just conducting.This conducting voltage parameter is determined by the resistance of normal setting voltage scope and the first divider resistance R501, the second divider resistance R502.Suppose that normal setting voltage scope is U1-U2, the conducting voltage parameter of conducting diode D505 is U0, then U0=R502/(R501+R502) * U2, flow through the cathode voltage=R502/(R501+R502 of conducting diode D505) * U10.
U1 is the minimum voltage that circuit normally works, when arranging the component parameters in first control circuit 40, must meet the following conditions: namely during input voltage U10=U1, the voltage flowing through V404 base stage after R401, R402 dividing potential drop is not less than cut-in voltage 0.7V, i.e. R402/(R401+R402) * U1=0.7V.
When input voltage U10 is greater than U2, after the first divider resistance R501 and the second divider resistance R502 dividing potential drop, the voltage flowing through conducting diode D505 negative pole is greater than the conducting voltage parameter U0 of conducting diode D505, conducting diode D505 conducting, now second control circuit 50 conducting; The output end voltage of V506 is the input terminal voltage of 0, V404 is 0, and first control circuit 40 ends, and switching tube V20 ends.
When input voltage U10 is within U1-U2, now after the first divider resistance R501 and the second divider resistance R502 dividing potential drop, the voltage flowing through conducting diode D505 negative pole is less than the conducting voltage parameter U0 of conducting diode D505, conducting diode D505 ends, therefore second control circuit 50 ends, and second control circuit 50 does not work to first control circuit 40; The voltage flowing through V404 input is greater than cut-in voltage, V404 conducting, first control circuit 40 conducting, switching tube V20 conducting.
When input voltage U10 is less than U1, the input terminal voltage flowing through V404 is less than V404 cut-in voltage, and V404 ends, and first control circuit 40 ends, and switching tube V20 also ends, and input voltage U10 cannot output to output voltage U30; The cathode voltage flowing through D505 is less than conducting voltage parameter U0, and D505 ends, and second control circuit 50 also ends.
Specific embodiment
Be illustrated in figure 5 the circuit theory diagrams of the specific embodiment of the invention, suppose that the normal setting voltage scope of low-pressure side overvoltage crowbar of the present invention is 8V-21V.
As shown in Figure 7, suppose that the resistance of the first divider resistance R501 is 20K Ω, the resistance of the second divider resistance R502 is 4.7K Ω, according to formula U0=R502/(R501+R502) * U2 can draw the conducting voltage parameter U0=3.9V of conducting diode D505.In the specific embodiment of the invention, first triode V506 can adopt 2SC2412K triode (being not limited thereto), second triode V404 can adopt 2SD1780 triode or 2SC1623 triode (being not limited thereto), and switching tube V20 can adopt 2SB1260 triode (being not limited thereto).
As Figure 6-Figure 7, each component parameters is set as follows: the first current-limiting resistance R503 is 1K Ω, and pull down resistor R504 is 1K Ω; 3rd divider resistance R401 is 20K Ω, and the 4th divider resistance R402 is 2K Ω, and the second current-limiting resistance R403 is 1.5K Ω, the resistor coupled in parallel composition of the 3rd current-limiting resistance R405 to be 5 resistances be 10K Ω.The parameter of above-mentioned each element can adjust according to the scope of the normal setting voltage of reality.
The cut-in voltage of the second triode V404 is 0.7V, when input voltage U10 is after R401 and R402 dividing potential drop, flow through voltage that resistance R403 arrives the input (in this specific embodiment for base stage) of the second triode V404 when reaching 0.7V, the conducting of V404 ability, thus the conducting of control switch pipe V20.
When input voltage U10 is between 8V-21V, such as, when being 15V, the dividing potential drop now flowing into conducting diode D505 negative pole is 4.7K Ω/(4.7K Ω+20K Ω) * 15V=2.8V, be less than the conducting voltage parameter 3.9V of conducting diode D505, conducting diode D505 ends, and therefore second control circuit 50 is in cut-off state; After R401 and R402 dividing potential drop, the base voltage flowing through the second triode V404 is 2K Ω/(2K Ω+20K Ω) * 15V=1.36V, is greater than 0.7V cut-in voltage, the second triode V404 conducting, therefore first control circuit 40 conducting, the conducting of first control circuit 40 control switch pipe V20.
When input voltage U10 is greater than 21V, such as, when being 30V, the dividing potential drop now flowing into conducting diode D505 negative pole is 4.7K Ω/(4.7K Ω+20K Ω) * 30V=5.7V, is greater than the conducting voltage parameter 3.9V of conducting diode D505, conducting diode D505 conducting, second control circuit 50 conducting.During second control circuit 50 conducting, output (being collector electrode in this specific embodiment) voltage of the first triode V506 is 0, input (being base stage in this specific embodiment) voltage of the second triode V404 in first control circuit 40 is also 0, first control circuit 40 ends, and switching tube V20 ends.
When input voltage U10 is less than 8V, such as, when being 5V, conducting diode D505 cathode voltage is 4.7K Ω/(4.7K Ω+20K Ω) * 5V=0.9V, and be less than 3.9V conducting voltage parameter, be in cut-off state, second control circuit 50 ends; The voltage flowing through the second triode V404 base stage is 2K Ω/(2K Ω+20K Ω) * 5V=0.45V, be less than V404 cut-in voltage 0.7V, V404 ends, and first control circuit 40 ends, therefore switching tube V20 is in cut-off state, and input voltage U10 cannot be passed to output voltage U30.
Low-pressure side overvoltage crowbar of the present invention; also can normally work at the lower voltage; the compound PTC not needing usage quantity numerous protects; protection real-time is fast; highly versatile; the load that can be control output voltage rear end by the present invention in real time is accurately not damaged; as long as there is fluctuation change in front end input voltage; second control circuit controls first control circuit; first control circuit controls switching tube, and loop control rapidly can reach the defencive function when low pressure input voltage over range.
The present invention can have multiple multi-form embodiment; above for Fig. 1-Fig. 7 by reference to the accompanying drawings to technical scheme of the present invention explanation for example; this does not also mean that the instantiation that the present invention applies can only be confined in specific flow process or example structure; those of ordinary skill in the art should understand; specific embodiments provided above is some examples in multiple its preferred usage, and the execution mode of any embodiment the claims in the present invention all should within technical solution of the present invention scope required for protection.
Last it is noted that the foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, although with reference to previous embodiment to invention has been detailed description, for a person skilled in the art, it still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein portion of techniques feature.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (7)
1. a low-pressure side overvoltage crowbar, it is characterized in that, comprise: switching tube, first control circuit, second control circuit, the output of described second control circuit is connected with the input of described first control circuit, the output of described first control circuit is connected with the base stage of described switching tube, and output voltage connected by the collector electrode of described switching tube; The emitter of described switching tube, described first control circuit, described second control circuit connect input voltage respectively;
Described second control circuit comprises: the first divider resistance, the second divider resistance, the first current-limiting resistance, pull down resistor, conducting diode, the first triode, input voltage is connected in one end of described first divider resistance, the other end of described first divider resistance is connected with one end of described second divider resistance, the other end ground connection of described second divider resistance; The common port of described first divider resistance, described second divider resistance is connected with the negative pole of described conducting diode;
One end of described pull down resistor is connected with the input of described first triode, and the other end of described pull down resistor is connected to the ground; The positive pole of described conducting diode is connected by described first current-limiting resistance with the common port of described pull down resistor, described first triode; The output of described first triode is connected with the input of described first control circuit.
2. low-pressure side overvoltage crowbar according to claim 1; it is characterized in that; described conducting diode is voltage stabilizing didoe; described conducting diode has conducting voltage parameter; described conducting voltage parameter is described input voltage when being normal setting voltage scope maximum, flows through the magnitude of voltage of described conducting diode negative pole after the first divider resistance and the second divider resistance dividing potential drop.
3. low-pressure side overvoltage crowbar according to claim 1, is characterized in that, the base stage of described first triode is input, and current collection is output very, the grounded emitter of described first triode.
4. low-pressure side overvoltage crowbar according to claim 1, it is characterized in that, described first control circuit comprises: the 3rd divider resistance, the 4th divider resistance, the second current-limiting resistance, the second triode, the 3rd current-limiting resistance, input voltage is connected in one end of described 3rd divider resistance, the other end of described 3rd divider resistance is connected with one end of described 4th divider resistance, and the other end of described 4th divider resistance is connected to the ground;
Described 3rd divider resistance, the common port of described 4th divider resistance are connected by described second current-limiting resistance with the input of described second triode, and the common port of described second current-limiting resistance, described second triode is connected with the output of described first triode;
The output of described second triode is connected by described 3rd current-limiting resistance with the base stage of described switching tube.
5. low-pressure side overvoltage crowbar according to claim 4, is characterized in that, the base stage of described second triode is input, and current collection is output very, the grounded emitter of described second triode.
6. low-pressure side overvoltage crowbar according to claim 4, is characterized in that, described 3rd current-limiting resistance is made up of multiple resistor coupled in parallel.
7. low-pressure side overvoltage crowbar according to claim 1, is characterized in that, also comprise electric capacity, and the collector electrode of described switching tube is connected with the positive pole of electric capacity, the minus earth of described electric capacity.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410115497.1A CN104953539A (en) | 2014-03-26 | 2014-03-26 | Low-voltage-side overvoltage protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410115497.1A CN104953539A (en) | 2014-03-26 | 2014-03-26 | Low-voltage-side overvoltage protection circuit |
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| CN104953539A true CN104953539A (en) | 2015-09-30 |
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| CN201410115497.1A Pending CN104953539A (en) | 2014-03-26 | 2014-03-26 | Low-voltage-side overvoltage protection circuit |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105305797A (en) * | 2015-10-15 | 2016-02-03 | 中国兵器工业集团第二一四研究所苏州研发中心 | Overvoltage and undervoltage protection circuit for output of DC/DC power supply |
| CN109149964A (en) * | 2018-08-28 | 2019-01-04 | 中国北方发动机研究所(天津) | A kind of alternator for vehicle power rectifier circuit with over-current over-voltage protection function |
| CN110474291A (en) * | 2019-09-20 | 2019-11-19 | 国网天津市电力公司 | A kind of distribution automation equipment power supply overvoltage protection device |
| CN111181129A (en) * | 2020-02-21 | 2020-05-19 | 德施曼机电（中国）有限公司 | Overvoltage protection circuit, charging equipment and electronic equipment |
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| CN101119028A (en) * | 2007-06-28 | 2008-02-06 | 深圳市中兴移动通信有限公司 | Electrical source input overvoltage protection circuit |
| CN201490685U (en) * | 2009-07-24 | 2010-05-26 | 深圳市中兴移动通信有限公司 | Multifunction power protection circuit |
| CN102780202A (en) * | 2011-05-09 | 2012-11-14 | 海洋王照明科技股份有限公司 | Overvoltage protection circuit and lamp |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101119028A (en) * | 2007-06-28 | 2008-02-06 | 深圳市中兴移动通信有限公司 | Electrical source input overvoltage protection circuit |
| CN201490685U (en) * | 2009-07-24 | 2010-05-26 | 深圳市中兴移动通信有限公司 | Multifunction power protection circuit |
| CN102780202A (en) * | 2011-05-09 | 2012-11-14 | 海洋王照明科技股份有限公司 | Overvoltage protection circuit and lamp |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105305797A (en) * | 2015-10-15 | 2016-02-03 | 中国兵器工业集团第二一四研究所苏州研发中心 | Overvoltage and undervoltage protection circuit for output of DC/DC power supply |
| CN105305797B (en) * | 2015-10-15 | 2017-11-14 | 中国兵器工业集团第二一四研究所苏州研发中心 | A kind of DC/DC power supplys output overvoltage under-voltage protecting circuit |
| CN109149964A (en) * | 2018-08-28 | 2019-01-04 | 中国北方发动机研究所(天津) | A kind of alternator for vehicle power rectifier circuit with over-current over-voltage protection function |
| CN110474291A (en) * | 2019-09-20 | 2019-11-19 | 国网天津市电力公司 | A kind of distribution automation equipment power supply overvoltage protection device |
| CN111181129A (en) * | 2020-02-21 | 2020-05-19 | 德施曼机电（中国）有限公司 | Overvoltage protection circuit, charging equipment and electronic equipment |
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