CN204144917U - A kind of overvoltage crowbar - Google Patents
A kind of overvoltage crowbar Download PDFInfo
- Publication number
- CN204144917U CN204144917U CN201420569000.9U CN201420569000U CN204144917U CN 204144917 U CN204144917 U CN 204144917U CN 201420569000 U CN201420569000 U CN 201420569000U CN 204144917 U CN204144917 U CN 204144917U
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- power supply
- resistance
- output
- earth terminal
- triode
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Abstract
The utility model relates to a kind of overvoltage crowbar.A kind of overvoltage crowbar, comprises, the first power supply; Second power supply; Output; Earth terminal; First switching device, is connected between the first power supply, output and earth terminal, the connection be selectively turned on or off between the first power supply and output under the effect of the first control signal; Second switch device, is connected between the second power supply, output and earth terminal, controllably disconnects or the connection of conducting second power supply and output when the first switch device conductive or cut-off.The utility model utilizes the open and close of metal-oxide-semiconductor to control conducting and the cut-out of product input power; when input power overvoltage; cut off input power; start stand-by power supply simultaneously; ball bearing made using is utilized to realize over-voltage protecting function; and less basic device of only need accelerating on original circuit base, occupy very little printed circuit board area.
Description
Technical field
The utility model relates to electronic technology field, is specifically related to a kind of overvoltage crowbar.
Background technology
Current electronics categories is more and more abundanter, ubiquitous in our life, the power supply needed when these electronic products normally work is mostly by carrying out Power convert realization to input power, as mostly used DC-DC chip to carry out Power convert, but when input power output voltage is abnormal or the input power of artificial origin's mistake in, the damage of DC-DC chip can be caused, product is caused normally to work, under serious conditions, also can damage, have very large potential safety hazard.In prior art, some electronic products arrange overvoltage protection mechanism, but overvoltage crowbar often more complicated, and price is more expensive.
Utility model content
The purpose of this utility model is, provides a kind of overvoltage crowbar, solves above technical problem.
The technical problem that the utility model solves can realize by the following technical solutions:
A kind of overvoltage crowbar, wherein, comprises,
First power supply;
Second power supply;
Output;
Earth terminal;
First switching device, is connected between described first power supply, described output and described earth terminal, the connection be selectively turned on or off between described first power supply and described output under the effect of the first control signal;
Second switch device, is connected between described second power supply, described output and described earth terminal, controllably disconnects or the connection of the second power supply and described output described in conducting when described first switch device conductive or cut-off.
Overvoltage crowbar of the present utility model; described first control signal is produced by one drive circuit; described drive circuit comprises a triode; the emitter of described triode connects described first power supply; the base stage of described triode connects a bias voltage by one second resistance; the collector electrode of described triode connects described earth terminal by one the 3rd resistance, and the collector electrode of described triode also connects a signal and exports branch road, and described signal exports branch road for exporting described first control signal.
Overvoltage crowbar of the present utility model; described first switching device adopts P channel MOS tube; the grid of described first switching device connects described first control signal; the source electrode of described first switching device connects described first power supply; the drain electrode of described first switching device is by one the 5th grounding through resistance, and the point that drain electrode and described 5th resistance of described first switching device are in series is connected described output.
Overvoltage crowbar of the present utility model; described second switch device adopts P channel MOS tube; the grid of described second switch device connects the drain electrode of described first switching device; the source electrode of described second switch device connects described second power supply, and the drain electrode of described second switch device connects described output.
Overvoltage crowbar of the present utility model, described signal exports series connection one the 4th resistance on branch road.
Overvoltage crowbar of the present utility model; described bias voltage is produced by a potential-divider network be connected between described first power supply and described earth terminal; described potential-divider network is in series by one first resistance and a voltage-stabiliser tube; described first resistance is connected with the positive pole of described voltage-stabiliser tube; the negative pole of described voltage-stabiliser tube connects described earth terminal, and the point that described first resistance and described voltage-stabiliser tube are in series exports described bias voltage.
Overvoltage crowbar of the present utility model, described triode adopts PNP type triode.
Beneficial effect: owing to adopting above technical scheme; the utility model utilizes the open and close of metal-oxide-semiconductor to control conducting and the cut-out of product input power; when input power overvoltage; cut off input power; start stand-by power supply simultaneously; ball bearing made using is utilized to realize over-voltage protecting function, and less basic device of only need accelerating on original circuit base, occupy very little printed circuit board area.
Accompanying drawing explanation
Fig. 1 is electrical block diagram of the present utility model.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, be clearly and completely described the technical scheme in the utility model embodiment, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiments.Based on the embodiment in the utility model, the every other embodiment that those of ordinary skill in the art obtain under the prerequisite of not making creative work, all belongs to the scope of the utility model protection.
It should be noted that, when not conflicting, the embodiment in the utility model and the feature in embodiment can combine mutually.
Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail, but not as restriction of the present utility model.
With reference to Fig. 1, a kind of overvoltage crowbar, wherein, comprises,
First power supply Vin;
Second power supply USB;
Output end vo ut;
Earth terminal GND;
First switching device Q2, is connected between the first power supply Vin, output end vo ut and earth terminal GND, the connection be selectively turned on or off between the first power supply Vin and output end vo ut under the effect of the first control signal;
Second switch device Q3, is connected between the second power supply USB, output end vo ut and earth terminal GND, controllably disconnects or the connection of conducting second power supply USB and output end vo ut when the first switching device Q2 conducting or cut-off.
The utility model can using the first power supply Vin as product input power, and the second power supply USB is as stand-by power supply, and output end vo ut connects the input port of DC-DC chip.Compared to common DC-DC chip all without input overvoltage protection, the utility model, when input power overvoltage, cuts off input power, starts stand-by power supply simultaneously, realize over-voltage protecting function, avoid causing damage to DC-DC chip.
Overvoltage crowbar of the present utility model; first control signal is produced by one drive circuit; drive circuit can comprise a triode Q1; the emitter of triode Q1 connects the first power supply Vin; the base stage of triode Q1 connects a bias voltage by one second resistance R2; the collector electrode of triode Q1 connects earth terminal GND by one the 3rd resistance R3, and the collector electrode of triode Q1 also connects a signal and exports branch road, and signal exports branch road for exporting the first control signal.In a kind of preferred embodiment, the collector electrode of one end connecting triode Q1 of signal output branch road can be connected one the 4th resistance R4, the 4th resistance R4, the other end, as the signal output part of drive circuit, exports the first control signal.
Overvoltage crowbar of the present utility model; first switching device Q2 can adopt P channel MOS tube; the grid of the first switching device Q2 receives the first control signal; the source electrode of the first switching device Q2 connects the first power supply Vin; the drain electrode of the first switching device Q2 connects earth terminal GND by one the 5th resistance R5, and the point that drain electrode and the 5th resistance R5 of the first switching device Q2 are in series is connected output end vo ut.
Overvoltage crowbar of the present utility model; second switch device Q3 adopts P channel MOS tube; the grid of second switch device Q3 connects the drain electrode of the first switching device Q2, and the source electrode of second switch device Q3 connects the second power supply USB, and the drain electrode of second switch device Q3 connects output end vo ut.
Above-mentioned P channel MOS tube preferably adopts the metal-oxide-semiconductor of enhancement mode to have better electrical property.
Overvoltage crowbar of the present utility model; bias voltage can be produced by a potential-divider network be connected between the first power supply Vin and earth terminal GND; potential-divider network is in series by one first resistance R1 and a voltage-stabiliser tube D1; first resistance R1 is connected with the positive pole of voltage-stabiliser tube D1; the minus earth of voltage-stabiliser tube D1, the some output offset voltage that the first resistance R1 and voltage-stabiliser tube D1 is in series.By one first resistance R1 and a voltage-stabiliser tube D1 be in series potential-divider network can solve be made up of resistant series merely potential-divider network job insecurity, be easy to the shortcoming of vibrating, bias voltage can be maintained and stablize, ensure circuit stability work.
When Circuit Selection, the burning voltage (Vz) of voltage-stabiliser tube D1 of the present utility model is greater than the first power supply Vin, and stay certain surplus, certainly can not be too large, if too large, just cannot play overvoltage protection effect, generally be less than the chip withstand voltage that interiors of products uses the first power supply Vin to power; As worked as the first power supply Vin=12V, the chip withstand voltage that interiors of products uses the first power supply Vin to power is 18V, and so Vz generally selects 14V ~ 17V.
The biasing resistor of the drive circuit that the second resistance R2 and the 3rd resistance R3 forms as triode Q1; The selection of the second resistance R2 resistance size will ensure that triode Q1 switches between cut-off and saturated two states.When the first power supply Vin is less than the burning voltage of voltage-stabiliser tube D1, voltage-stabiliser tube D1 is in high-impedance state, and the base stage of triode Q1 is high level, and triode Q1 is in cut-off state; When the first power supply Vin is greater than the burning voltage of voltage-stabiliser tube D1, at this moment to ensure that triode Q1 is in saturation condition, i.e. (Vin-Vz-Vbe) * β/R1> (Vin-Vces)/R2,
Wherein, Vbe is triode Q1 base-on voltage, is generally 0.7V, and Vces is the saturation voltage of triode Q1, is generally 0.3V, and β is the amplification coefficient of triode Q1, usually from tens to several thousand.
The simultaneously selection of the 4th resistance R4 also will ensure that the collector current of triode Q1 is less than that transistor collector is maximum bears electric current I cm, i.e. (Vin-Vces)/R2<Icm.Usual second resistance R2 and the 3rd resistance R3 gets the resistance value of K Ω rank.A kind of specific embodiment, resistance value selects value to be 4.7k Ω.
Overvoltage crowbar of the present utility model; triode Q1 uses as switching tube; namely cut-off and saturated two states is in; therefore triode Q1 will select PNP type triode; the opening and closing time of pipe is more short better simultaneously; the response time of such switching tube is shorter, can be better to the protective effect of product.The switching tube of current a lot of models on the market can meet this demand.
First switching device Q2 and second switch device Q3 can select P-channel enhancement type metal-oxide-semiconductor, when satisfied first power supply Vin normally exports, product can normally work, first switching device Q2 will be in conducting state, i.e. Vgs>Vth, Vth is the cut-in voltage of the first switching device Q2, and Vgs is provided through drive circuit by the first power supply Vin, therefore Vgs<Vin.Second switch device Q3 is in cut-off state.
And when the first power supply Vin exceeds designing requirement, then the first switching device Q2 will be in cut-off state, and second switch device Q3 is in conducting state, makes stand-by power supply, and namely the second power supply USB is in running order, can normally work to make product.
When selection first switching device Q2 and second switch device Q3, the maximum drain-source current Idsm meeting metal-oxide-semiconductor is greater than the full-load current on product first power supply Vin, and the full-load current on usual first power supply Vin wants <0.8*Idsm.Simultaneously also will to meet conducting resistance Ron little as far as possible for the first switching device Q2 and second switch device Q3, because conducting resistance is less, the power consumption of metal-oxide-semiconductor is less, has less power consumption to make whole circuit.The conducting resistance of current P channel MOS tube on the market can accomplish hundreds of milliohm, can meet this requirement.First switching device Q2 and the second switch device Q3 response time shorter, also better to the protected effect of product.
Circuit working principle of the present utility model:
When the first power supply Vin is normal, namely produce the input power adapter of the first power supply Vin normal time, due to the first power supply Vin<Vz (burning voltage of voltage-stabiliser tube D1), voltage-stabiliser tube D1 is in high-impedance state, the base stage of triode Q1 is high level, therefore triode Q1 ends, and the grid of the P-channel enhancement type metal-oxide-semiconductor of now the first switching device Q2 employing is low level, therefore the drain electrode of the first switching device Q2 and source conduction, i.e. Vout=Vin; And the grid of second switch device Q3 is high level, the drain electrode of second switch device Q3 and source electrode not conducting, the second power supply USB powers inoperative.
When the first power supply Vin is abnormal, when inputting excessive, i.e. Vin>Vz (burning voltage of voltage-stabiliser tube D1), voltage-stabiliser tube D1 is in low resistive state, now the base stage of triode Q1 is compared to current collection very high level, emitter conducting, simultaneously owing to being added in the effect of the bias voltage Vin of the collector electrode of triode Q1, switching tube Q1 is in saturation condition, emitter and collector electrode conducting, so time triode Q1 current collection very high level, thus the grid voltage of the first switching device Q2 is high level, first switching device Q2 ends, drain electrode and the source electrode of the first switching device Q2 disconnect, first power supply Vin cannot be transferred to output end vo ut, the grid of second switch device Q3 is due to pull down resistor simultaneously, i.e. the first resistance R5 ground connection, for low level, drain electrode and source conduction, output end vo ut is powered by the second power supply USB, product can continue normal work.
The utility model utilizes the open and close of metal-oxide-semiconductor to control conducting and the cut-out of product input power; when input power overvoltage; cut off input power; start stand-by power supply simultaneously; ball bearing made using is utilized to realize over-voltage protecting function; and less basic device of only need accelerating on original circuit base, occupy very little printed circuit board area.
These are only the utility model preferred embodiment; not thereby execution mode of the present utility model and protection range is limited; to those skilled in the art; should recognize and all should be included in the scheme that equivalent replacement done by all utilization the utility model specifications and diagramatic content and apparent change obtain in protection range of the present utility model.
Claims (7)
1. an overvoltage crowbar, is characterized in that, comprises,
First power supply;
Second power supply;
Output;
Earth terminal;
First switching device, is connected between described first power supply, described output and described earth terminal, the connection be selectively turned on or off between described first power supply and described output under the effect of the first control signal;
Second switch device, is connected between described second power supply, described output and described earth terminal, controllably disconnects or the connection of the second power supply and described output described in conducting when described first switch device conductive or cut-off.
2. overvoltage crowbar according to claim 1; it is characterized in that; described first control signal is produced by one drive circuit; described drive circuit comprises a triode; the emitter of described triode connects described first power supply; the base stage of described triode connects a bias voltage by one second resistance; the collector electrode of described triode connects described earth terminal by one the 3rd resistance; the collector electrode of described triode also connects a signal and exports branch road, and described signal exports branch road for exporting described first control signal.
3. overvoltage crowbar according to claim 1; it is characterized in that; described first switching device adopts P channel MOS tube; the grid of described first switching device connects described first control signal; the source electrode of described first switching device connects described first power supply; the drain electrode of described first switching device connects described earth terminal by one the 5th resistance, and the point that drain electrode and described 5th resistance of described first switching device are in series is connected described output.
4. overvoltage crowbar according to claim 3; it is characterized in that; described second switch device adopts P channel MOS tube; the grid of described second switch device connects the drain electrode of described first switching device; the source electrode of described second switch device connects described second power supply, and the drain electrode of described second switch device connects described output.
5. overvoltage crowbar according to claim 2, is characterized in that, described signal exports series connection one the 4th resistance on branch road.
6. overvoltage crowbar according to claim 2; it is characterized in that; described bias voltage is produced by a potential-divider network be connected between described first power supply and described earth terminal; described potential-divider network is in series by one first resistance and a voltage-stabiliser tube; described first resistance is connected with the positive pole of described voltage-stabiliser tube; the negative pole of described voltage-stabiliser tube connects described earth terminal, and the point that described first resistance and described voltage-stabiliser tube are in series exports described bias voltage.
7. overvoltage crowbar according to claim 2, is characterized in that, described triode adopts PNP type triode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420569000.9U CN204144917U (en) | 2014-09-29 | 2014-09-29 | A kind of overvoltage crowbar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420569000.9U CN204144917U (en) | 2014-09-29 | 2014-09-29 | A kind of overvoltage crowbar |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204144917U true CN204144917U (en) | 2015-02-04 |
Family
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420569000.9U Expired - Fee Related CN204144917U (en) | 2014-09-29 | 2014-09-29 | A kind of overvoltage crowbar |
Country Status (1)
| Country | Link |
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| CN (1) | CN204144917U (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106341036A (en) * | 2016-09-23 | 2017-01-18 | 武汉烽火众智数字技术有限责任公司 | Circuit with overvoltage protection and current accumulation |
| CN109491442A (en) * | 2018-11-07 | 2019-03-19 | 深圳市风云实业有限公司 | Voltage monitoring circuit and voltage monitoring systems |
| CN109580997A (en) * | 2018-11-30 | 2019-04-05 | 泸州威恩德科技有限公司 | Test fixture, test device and test macro |
| CN111193244A (en) * | 2018-11-14 | 2020-05-22 | 厦门雅迅网络股份有限公司 | Direct current power supply output circuit protection circuit |
| CN116054082A (en) * | 2023-03-27 | 2023-05-02 | 南京捷希科技有限公司 | Overvoltage protector for programmable power supply |
| CN117707318A (en) * | 2024-02-05 | 2024-03-15 | 苏州元脑智能科技有限公司 | Power supply circuit |
-
2014
- 2014-09-29 CN CN201420569000.9U patent/CN204144917U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106341036A (en) * | 2016-09-23 | 2017-01-18 | 武汉烽火众智数字技术有限责任公司 | Circuit with overvoltage protection and current accumulation |
| CN109491442A (en) * | 2018-11-07 | 2019-03-19 | 深圳市风云实业有限公司 | Voltage monitoring circuit and voltage monitoring systems |
| CN111193244A (en) * | 2018-11-14 | 2020-05-22 | 厦门雅迅网络股份有限公司 | Direct current power supply output circuit protection circuit |
| CN109580997A (en) * | 2018-11-30 | 2019-04-05 | 泸州威恩德科技有限公司 | Test fixture, test device and test macro |
| CN116054082A (en) * | 2023-03-27 | 2023-05-02 | 南京捷希科技有限公司 | Overvoltage protector for programmable power supply |
| CN117707318A (en) * | 2024-02-05 | 2024-03-15 | 苏州元脑智能科技有限公司 | Power supply circuit |
| CN117707318B (en) * | 2024-02-05 | 2024-04-26 | 苏州元脑智能科技有限公司 | Power supply circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 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: 20150204 Termination date: 20190929 |