CN203813406U - Over-current and overvoltage protection circuit - Google Patents
Over-current and overvoltage protection circuit Download PDFInfo
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- CN203813406U CN203813406U CN201420195002.6U CN201420195002U CN203813406U CN 203813406 U CN203813406 U CN 203813406U CN 201420195002 U CN201420195002 U CN 201420195002U CN 203813406 U CN203813406 U CN 203813406U
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- 230000005669 field effect Effects 0.000 claims abstract description 37
- 238000005070 sampling Methods 0.000 claims abstract description 27
- 230000000087 stabilizing effect Effects 0.000 claims description 6
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 230000006641 stabilisation Effects 0.000 abstract 1
- 238000011105 stabilization Methods 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 5
- 230000001681 protective effect Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000002457 bidirectional effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 101000669528 Homo sapiens Tachykinin-4 Proteins 0.000 description 1
- OKUGPJPKMAEJOE-UHFFFAOYSA-N S-propyl dipropylcarbamothioate Chemical compound CCCSC(=O)N(CCC)CCC OKUGPJPKMAEJOE-UHFFFAOYSA-N 0.000 description 1
- 102100039365 Tachykinin-4 Human genes 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
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- Metal-Oxide And Bipolar Metal-Oxide Semiconductor Integrated Circuits (AREA)
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Abstract
The utility model discloses an over-current and overvoltage protection circuit. The over-current and overvoltage protection circuit includes an N channel field effect transistor Q1 comprising a first grid electrode, a first source electrode, and a first drain electrode, and a P channel field effect transistor Q2 comprising a second grid electrode, a second source electrode, and a second drain electrode. The over-current and overvoltage protection circuit is characterized by also comprising an N channel field effect transistor Q3 comprising a third grid electrode, a third source electrode, and a third drain electrode, wherein the third drain electrode is connected with the first drain electrode, at least one level of voltage sampling circuit is disposed between the third source electrode and the second drain electrode, each level of the voltage sampling circuit is composed of any of a resistor element, a voltage stabilization diode, or a light emitting diode, or the combination thereof, and the second grid electrode and the third grid electrode are connected on a sampling point of the sample circuit at any level. The over-current and overvoltage protection circuit has beneficial effects of being simple in circuit structure, being safe and convenient to use, being adaptable for different voltage ranges through selecting different grid electrode sampling points, being high in speed, being recoverable, and being safe and reliable.
Description
Technical field
The utility model relates to electronic circuit technology, specifically, is a kind of overcurrent-overvoltage protecting circuit.
Background technology
Existing overcurrent-overvoltage protecting circuit adopts protective tube conventionally, and thermometal protective tube and PPTC are from recovering insurance, and these several reaction speeds are slow, and the recovery certainly having, and be difficult to really play the effect of protective circuit and device.Although some overcurrent-overvoltage protecting circuits can recover, circuit structure complexity, can not serve as an independently device use, and cost is high, can be used as high speed communication, the over-current over-voltage protection of interface circuit and power supply, surge and lightning strike protection.
As shown in Figure 1; field effect transistor is usually used as switch element and current-limiting protection element because of the impedance transformation characteristic of himself; it shown in figure, is a typical protective circuit; Q1, Q2 are depletion field effect transistor; by Q1, the series connection of Q2 common source; along with the increase of circuit two ends electric current; electric current by Q1, Q2 will form grid voltage; once electric current exceedes predetermined threshold; grid voltage easily causes field effect transistor cut-off; make it in high-impedance state, thereby the load of protection series connection realize current-limiting protection.
Although sort circuit is simple in structure, can be used as independently device and use, due to the restriction of field effect transistor self-characteristic, two pipe voltage scenes that simply series connection adapts to are limited, and the input/output bound of circuit is narrower.
Utility model content
In order to overcome the deficiencies in the prior art; the purpose of this utility model is to propose a kind of overcurrent-overvoltage protecting circuit that adapts to multiple voltage scope; on the basis of the connected field effect transistor current-limiting protection circuit of existing common source; adjust the grid voltage of each field effect transistor by setting up voltage sampling circuit; make it possess wider input-output characteristic; circuit entirety can integratedly independently be used as two terminal device simultaneously, cost-saving.
For achieving the above object, the concrete technical scheme that the utility model adopts is as follows:
A kind of overcurrent-overvoltage protecting circuit, comprise and there is first grid, the first source electrode, the N channel field-effect pipe Q1 of the first drain electrode and there is second grid, the second source electrode, the P-channel field-effect transistor (PEFT) pipe Q2 of the second drain electrode, wherein, the first source electrode is connected with the second source electrode, the first drain electrode connects high level end, the second drain electrode connects low level end, first grid and the second drain electrode are electrical connected, its key is: also comprise and have the 3rd grid, the 3rd source electrode, the N channel field-effect pipe Q3 of the 3rd drain electrode, wherein, the 3rd drain electrode is connected with the first drain electrode, between the 3rd source electrode and the second drain electrode or the 3rd source electrode and the second source electrode, be provided with at least one step voltage sample circuit, every step voltage sample circuit is respectively by resistive element, in zener diode or light-emitting diode three any one or its constitute, described second grid and the 3rd grid are connected on the sampled point of any one-level voltage sampling circuit.
Design based on foregoing circuit; field effect transistor Q3 can be used as constant-current source; realize current limliting and the pressure limiting effect of multilevel voltage sample circuit; by multilevel voltage sample circuit is set; can, for field effect transistor Q2 provides different grid voltages, can select different grid voltage sampled points according to the demand of input and output voltage scope, realize the application of several scenes; light-emitting diode is set in voltage sampling circuit as indicator light, the state instruction while can be used as over-current over-voltage protection.
In order to play the effect of delay protection, on the minimum one-level voltage sampling circuit of voltage, going back parallel join has capacity cell.
In order further to realize overvoltage protection, described first grid and the second drain electrode are electrical connected by resistance R 1, pass through resistance R 2 or/and voltage stabilizing didoe D1 receives overvoltage protection control signal at the high level end of resistance R 1.
For the ease of implementing, described field effect transistor Q1 and field effect transistor Q2 are JFET field effect transistor or depletion type MOS FET field effect transistor.
Remarkable result of the present utility model is: circuit structure is simple; use safety, convenient; select different grid voltage sampled points can adapt to different voltage ranges; circuit entirety can be used as two terminal device or three terminal device independently uses; circuit, modular assembly, power device and interface circuit are played to overcurrent protection and the interference of blocking-up high pressure; realization can restore funcitons, and current-limiting protection is quick, safe and reliable.
Brief description of the drawings
Fig. 1 is current-limiting protection circuit of the prior art;
Fig. 2 is circuit topology figure of the present utility model;
Fig. 3 is the circuit topology figure that the utility model increase adds overvoltage protection control function;
Fig. 4 is the circuit theory diagrams of specific embodiment 1;
Fig. 5 is the circuit theory diagrams of specific embodiment 2;
Fig. 6 is the circuit theory diagrams of specific embodiment 3;
Fig. 7 is the circuit theory diagrams of specific embodiment 4.
Embodiment
Below in conjunction with accompanying drawing, embodiment of the present utility model and operation principle are described in further detail.
As shown in Figure 2, a kind of overcurrent-overvoltage protecting circuit, comprise and there is first grid, the first source electrode, the N channel field-effect pipe Q1 of the first drain electrode, there is second grid, the second source electrode, the P-channel field-effect transistor (PEFT) pipe Q2 of the second drain electrode, there is the 3rd grid, the 3rd source electrode, the N channel field-effect pipe Q3 of the 3rd drain electrode, wherein, the first source electrode is connected with the second source electrode, the first drain electrode connects high level end, the second drain electrode connects low level end, first grid and the second drain electrode are electrical connected, the 3rd drain electrode is connected with the first drain electrode, between the 3rd source electrode and the second drain electrode, be provided with at least one step voltage sample circuit, Figure 2 shows that three grades, every step voltage sample circuit is respectively by resistive element, in zener diode or light-emitting diode three any one or its constitute, described second grid and the 3rd grid are connected on the sampled point of any one-level voltage sampling circuit, on the minimum one-level voltage sampling circuit of voltage, go back parallel join and have capacity cell, certainly, also can be arranged between the 3rd source electrode and the second source electrode as voltage sampling circuit, its operation principle is identical, just the sampled point of low level end is different.
As shown in Figure 3, in order further to promote the effect of overvoltage protection, described first grid and the second drain electrode are electrical connected by resistance R 1, pass through resistance R 2 or/and voltage stabilizing didoe D1 receives overvoltage protection control signal at the high level end of resistance R 1.
For the ease of implementing, described field effect transistor Q1 and field effect transistor Q2 are JFET field effect transistor or depletion type MOS FET field effect transistor.
Below by enumerating several concrete implementing circuits, the utility model is described further:
Specific embodiment 1:
As shown in Figure 4, adopt depletion type MOS FET field effect transistor as Q1, Q2, Q3, it can also be seen that from Fig. 4, in the present embodiment, be designed with two-stage voltage sampling circuit, first order voltage sampling circuit is made up of voltage stabilizing didoe D2, second level voltage sampling circuit is made up of resistance R 3, the grid of field effect transistor Q2 is connected to the high level end of second level voltage sampling circuit, the grid of field effect transistor Q3 is connected to the high level end of first order voltage sampling circuit, the grid voltage of Q2 is higher than the grid voltage of Q3, thereby adapts to a kind of voltage input/output bound.
Specific embodiment 2:
As shown in Figure 5; the difference of the present embodiment and embodiment 1 is; first order voltage sampling circuit adopts light-emitting diode composition; shown in figure, be LED; and second grid is connected to the high level end of first order voltage sampling circuit; the 3rd grid is connected to the high level end of second level voltage sampling circuit; thereby make the grid voltage of Q2 lower than the grid voltage of Q3; thereby adapt to another kind of voltage input/output bound; and be beneficial to light-emitting diode as voltage sampling circuit; in the time that circuit plays current-limiting protection, can provide system mode instruction by LED is luminous.
Specific embodiment 3:
As shown in Figure 6, the difference of the present embodiment and embodiment 2 is, on first order voltage sampling circuit, is parallel with capacitor C, by setting up capacity cell, can play the effect of delay start protection, and can realize the effect of delayed recovery.
Specific embodiment 4:
As shown in Figure 7, in this example, first order voltage sampling circuit adopts resistance R 4 to form, second level voltage sampling circuit adopts resistance R 3 to form, second grid is connected to the high level end of second level voltage sampling circuit, the 3rd grid is connected to the high level end of first order voltage sampling circuit, make the grid voltage of Q2 higher than the grid voltage of Q3, and be serially connected with resistance R 1 between first grid and the second drain electrode, receive overvoltage protection control signal by voltage stabilizing didoe D1, now whole module is used as three terminal device, in the time that circuit exceedes predeterminated voltage, the voltage that voltage stabilizing didoe D1 obtains is enough to make field effect transistor Q1 cut-off, if the electric current in circuit exceedes predetermined threshold value, the voltage that resistance R 4 and resistance R 3 gather is enough to make field effect transistor Q2 cut-off, finally make circuit two ends realize over-current over-voltage protection.
Above-mentioned circuit is mainly used in realizing Unidirectional direct-current over-current over-voltage protection; in order to realize bidirectional protective, use two overcurrent-overvoltage protecting circuits of said structure anodal to be connected with anodal mirror image or negative pole and negative pole mirror image connect to form bidirectional flow-through overvoltage crowbar.
Finally it should be noted that, although the utility model is described with reference to various embodiments of the present utility model here, but, should be appreciated that, those skilled in the art can also design a lot of other amendment and execution modes, within these amendments and execution mode will drop on the disclosed principle scope and spirit of the application.More particularly, in the scope of, accompanying drawing open in the application and claim, can carry out multiple modification and improvement to the building block of circuit composite configuration and/or layout.Except modification that building block and/or layout are carried out with improving, to those skilled in the art, other purposes will be also obvious.
Claims (4)
1. an overcurrent-overvoltage protecting circuit, comprise and there is first grid, the first source electrode, the N channel field-effect pipe Q1 of the first drain electrode and there is second grid, the second source electrode, the P-channel field-effect transistor (PEFT) pipe Q2 of the second drain electrode, wherein, the first source electrode is connected with the second source electrode, the first drain electrode connects high level end, the second drain electrode connects low level end, first grid and the second drain electrode are electrical connected, it is characterized in that: also comprise and there is the 3rd grid, the 3rd source electrode, the N channel field-effect pipe Q3 of the 3rd drain electrode, wherein, the 3rd drain electrode is connected with the first drain electrode, between the 3rd source electrode and the second drain electrode or the 3rd source electrode and the second source electrode, be provided with at least one step voltage sample circuit, every step voltage sample circuit is respectively by resistive element, in zener diode or light-emitting diode three any one or its constitute, described second grid and the 3rd grid are connected on the sampled point of any one-level voltage sampling circuit.
2. a kind of overcurrent-overvoltage protecting circuit according to claim 1, is characterized in that: on the minimum one-level voltage sampling circuit of voltage, going back parallel join has capacity cell.
3. a kind of overcurrent-overvoltage protecting circuit according to claim 1 and 2; it is characterized in that: described first grid and the second drain electrode are electrical connected by resistance R 1, pass through resistance R 2 or/and voltage stabilizing didoe D1 receives overvoltage protection control signal at the high level end of resistance R 1.
4. a kind of overcurrent-overvoltage protecting circuit according to claim 1, is characterized in that: described field effect transistor Q1 and field effect transistor Q2 are JFET field effect transistor or depletion type MOS FET field effect transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420195002.6U CN203813406U (en) | 2014-04-21 | 2014-04-21 | Over-current and overvoltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420195002.6U CN203813406U (en) | 2014-04-21 | 2014-04-21 | Over-current and overvoltage protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203813406U true CN203813406U (en) | 2014-09-03 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420195002.6U Expired - Fee Related CN203813406U (en) | 2014-04-21 | 2014-04-21 | Over-current and overvoltage protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203813406U (en) |
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2014
- 2014-04-21 CN CN201420195002.6U patent/CN203813406U/en not_active Expired - Fee Related
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| C14 | Grant of patent or utility model | ||
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140903 |
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| CF01 | Termination of patent right due to non-payment of annual fee |