CN203289075U - Overvoltage protection circuit - Google Patents
Overvoltage protection circuit Download PDFInfo
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- CN203289075U CN203289075U CN2013203220466U CN201320322046U CN203289075U CN 203289075 U CN203289075 U CN 203289075U CN 2013203220466 U CN2013203220466 U CN 2013203220466U CN 201320322046 U CN201320322046 U CN 201320322046U CN 203289075 U CN203289075 U CN 203289075U
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Abstract
The utility model discloses an overvoltage protection circuit which comprises a voltage-stabilized power supply circuit and a switching circuit. The voltage-stabilized power supply circuit comprises a three-end voltage stabilizing tube, wherein a negative electrode of the three-end voltage stabilizing tube is electrically connected with an input power supply through a first current-limiting resistor, a reference electrode of the three-end voltage stabilizing tube is electrically connected with a common node of two serially connected first divider resistors which are electrically connected to the negative electrode, and a positive electrode of the three-end voltage stabilizing tube and one ends, which are away from the negative electrode, of the two serially connected divider resistors are all grounded; and the negative electrode of the three-end voltage stabilizing tube is electrically connected with the switching circuit. The overvoltage protection circuit disclosed by the utility model is low in cost, and voltage of overvoltage protection can be set according to requirements.
Description
Technical field
The utility model relates to the circuit design technique field, specifically, relates to a kind of overvoltage crowbar.
Background technology
If the supply voltage of power circuit is too high, will cause the components and parts work in power circuit undesired, the serious components and parts in power circuit that also can cause burn.Therefore, for guaranteeing the performance and used life of components and parts in power circuit, extremely important to its overvoltage protection.
At present, adopt overvoltage crowbar to carry out overvoltage protection to power circuit more.And present overvoltage crowbar adopts the DCDC module of wide voltage input more or uses integrated OVP(Overvoltage protection) chip realizes.But the DCDC module of wide voltage input, not from turn-off function, therefore, when input voltage is too high, can cause burning the situation of components and parts in power circuit after input voltage surpasses the input range of its regulation; And adopt the OVP integrated chip to realize overvoltage protection, and not only cost is higher, and protection voltage is generally the value of fixing, and inconvenience arranges arbitrarily, and its current requirements is also many below 1.5A, is not suitable for the power circuit of large electric current.
The utility model content
Technical problem to be solved in the utility model is: the overvoltage crowbar that a kind of cost is low, the overvoltage protection magnitude of voltage can arrange as required is provided.
For solving the problems of the technologies described above, the technical solution of the utility model is:
A kind of overvoltage crowbar, comprise voltage-stabilized power supply circuit and switching circuit; Described voltage-stabilized power supply circuit comprises the three-terminal voltage-stabilizing pipe, the negative electrode of described three-terminal voltage-stabilizing pipe is electrically connected to input power by the first current-limiting resistance, the reference utmost point of described three-terminal voltage-stabilizing pipe is electrically connected to the common node of two that are electrically connected to described negative electrode the first divider resistances of connecting, the anode of described three-terminal voltage-stabilizing pipe and the end equal ground connection of described two the first divider resistances of connecting away from described three-terminal voltage-stabilizing tube cathode; The negative electrode of described three-terminal voltage-stabilizing pipe is electrically connected to described switching circuit.
Preferably, described switching circuit comprises the first switch element, second switch element and the 3rd switch element, and described the first switch element, described second switch element and described the 3rd switch element comprise respectively first end, the second end and be used for controlling the control end of described first end and described the second end conducting;
The control end of described the first switch element is electrically connected to the common node of two that are electrically connected to described three-terminal voltage-stabilizing tube cathode the second divider resistances of connecting, its control end also is connected with the second current-limiting resistance, its second end and the end equal ground connection of described two the second divider resistances of connecting away from described three-terminal voltage-stabilizing tube cathode, its first end is electrically connected to described input power by the 3rd current-limiting resistance, and its first end also is electrically connected to the control end of described second switch element;
The first end of described second switch element is electrically connected to described input power by the 4th current-limiting resistance, the second equal ground connection of end of its second end and described the first switch element, and its first end also is electrically connected to the control end of described the 3rd switch element;
The first end of described the 3rd switch element is electrically connected to described input power, and its second end is voltage output end.
Preferably, described the first switch element and described second switch element are the NPN triode, and its first end is collector electrode, and its second end is emitter, and its control end is base stage.
Preferably, described the 3rd switch element is P type metal-oxide-semiconductor, and its first end is source electrode, and its second end is drain electrode, and its control end is grid.
Preferably, the first divider resistance of described two series connection comprises resistance (R3) and the resistance (R4) of series connection, one end of resistance (R3) is electrically connected to the first current-limiting resistance (R1), the other end of resistance (R3) is electrically connected to an end of resistance (R4), the equal ground connection of anode of the other end of resistance (R4) and described three-terminal voltage-stabilizing pipe; The second divider resistance of described two series connection comprises resistance (R5) and the resistance (R6) of series connection, one end of resistance (R5) is connected with the cathodic electricity of described three-terminal voltage-stabilizing pipe, the other end of resistance (R5) is electrically connected to an end of resistance (R6), the second equal ground connection of end of the other end of resistance (R6) and the second end of the first switch element and second switch element.
Preferably, the first current-limiting resistance (R1), resistance (R3), resistance (R4), resistance (R5) and resistance (R6) need meet the following conditions: VDD1*R4/ (R4+R3)=Vref, R6*VDD/ (R1+R5+R6)＜0.7V, and R6*VDD1/ (R5+R6)〉0.7V; Wherein, VDD is the voltage of input power, and VDD1 is overvoltage protection voltage, and Vref is the reference voltage of three-terminal voltage-stabilizing pipe.
Preferably, described three-terminal voltage-stabilizing pipe is TL43 series.
Preferably, described three-terminal voltage-stabilizing pipe is TL431 voltage-stabiliser tube or TL432 voltage-stabiliser tube.
After having adopted technique scheme, the beneficial effects of the utility model are:
Overvoltage crowbar of the present utility model in use; suppose that the overvoltage protection voltage that needs to set is VDD1; as input voltage VDD during lower than the overvoltage protection voltage VDD1 that sets; the reference utmost point R input voltage of three-terminal voltage-stabilizing pipe is lower than Vref; namely lower than the internal reference voltage of three-terminal voltage-stabilizing pipe, the cut-off of three-terminal voltage-stabilizing pipe, make the switching circuit conducting; thereby make voltage output end output voltage VO UT=VDD, output voltage V DD powers to the postorder power circuit.
And when input voltage VDD meets or exceeds the overvoltage protection voltage VDD1 of setting; the reference edge input voltage of three-terminal voltage-stabilizing pipe meets or exceeds Vref; namely meet or exceed the internal reference voltage of three-terminal voltage-stabilizing pipe; the value of the first divider resistance by adjusting two series connection, make the voltage stabilization of negative electrode of three-terminal voltage-stabilizing pipe at overvoltage protection voltage VDD1.Make the switching circuit cut-off, the output voltage VO of breaking UT.Thereby avoid too high input voltage VDD to cause damage to the components and parts in the postorder power circuit, played the effect of overvoltage protection.
Therefore overvoltage crowbar of the present utility model, adopted the three-terminal voltage-stabilizing pipe to realize the overvoltage protection of power circuit, without the OVP integrated chip, simple in structure, cost is low.And, due to the value of the first divider resistance by adjusting two series connection, can adjust the set point VDD1 of overvoltage protection voltage.Therefore the overvoltage protection magnitude of voltage can be set according to actual needs easily.
Description of drawings
The utility model is described in further detail below in conjunction with drawings and Examples:
Fig. 1 is the principle schematic of overvoltage crowbar of the present utility model;
In figure: 1, voltage-stabilized power supply circuit; 11, three-terminal voltage-stabilizing pipe; 12, the first divider resistance of two series connection; R1, the first current-limiting resistance; 2, switching circuit; 21, the first switch element; 22, second switch element; 23, the 3rd switch element; 24, the second divider resistance of two series connection; R8, the second current-limiting resistance; R9, the 3rd current-limiting resistance; R2, the 4th current-limiting resistance.
Embodiment
Fig. 1 is the principle schematic of overvoltage crowbar of the present utility model, and with reference to Fig. 1, overvoltage crowbar of the present utility model, comprise voltage-stabilized power supply circuit 1 and switching circuit 2; Voltage-stabilized power supply circuit 1 comprises three-terminal voltage-stabilizing pipe 11, the negative electrode K end of three-terminal voltage-stabilizing pipe 11 is electrically connected to input power VDD by the first current-limiting resistance R1, the reference utmost point R end of three-terminal voltage-stabilizing pipe 11 is electrically connected to the common node of two the first divider resistances 12 of connecting that are electrically connected to negative electrode K end, and the first divider resistance 12 that the anode A end of three-terminal voltage-stabilizing pipe 11 is connected with two is away from the equal ground connection of end of the negative electrode K end of three-terminal voltage-stabilizing pipe 11; The negative electrode K end of three-terminal voltage-stabilizing pipe 11 is electrically connected to switching circuit 2.In the present embodiment, the first divider resistance 12 of two series connection comprises resistance R 3 and the resistance R 4 of series connection, one end of resistance R 3 is electrically connected to the first current-limiting resistance R1, and the other end of resistance R 3 is electrically connected to an end of resistance R 4, the equal ground connection of anode A end of the other end of resistance R 4 and three-terminal voltage-stabilizing pipe.
The control end of the first switch element 21 is electrically connected to the common node of two the second divider resistances 24 of connecting of the negative electrode K end that is electrically connected to three-terminal voltage-stabilizing pipe 11, its control end also is connected with the second current-limiting resistance R8, the second divider resistance 24 that its second end is connected with two is away from the equal ground connection of end of the negative electrode K end of three-terminal voltage-stabilizing pipe 11, its first end is electrically connected to input power VDD by the 3rd current-limiting resistance R9, and its first end also is connected with the control end of second switch element 22.
The first end of second switch element 22 is electrically connected to input power VDD by the 4th current-limiting resistance R2, the second equal ground connection of end of its second end and the first switch element 21, and the control end of its first end the also with three switch element 23 is connected.
The first end of the 3rd switch element 23 is electrically connected to input power VDD, and its second end is voltage output end VOUT.
In the present embodiment, the second divider resistance 24 of two series connection comprises resistance R 5 and the resistance R 6 of series connection, one end of resistance R 5 is connected with the cathodic electricity of three-terminal voltage-stabilizing pipe, the other end of resistance R 5 is electrically connected to an end of resistance R 6, the second equal ground connection of end of the second end of the other end of resistance R 6 and the first switch element 21 and second switch element 22.The first switch element 21 and second switch element 22 are the NPN triode, and its first end is collector electrode, and its second end is emitter, and its control end is base stage.The 3rd switch element 23 is P type metal-oxide-semiconductor, and its first end is source electrode, and its second end is drain electrode, and its control end is grid.
in the present embodiment, described three-terminal voltage-stabilizing pipe 11 is the TL431 voltage-stabiliser tube, its internal reference voltage (or claiming conducting voltage) Vref is 2.5V, when setting overvoltage protection voltage is VDD1, the selection of resistance R 3 and resistance R 4 should satisfy condition: VDD1*R4/ (R4+R3)=2.5V, the first current-limiting resistance R1, the selection of resistance R 5 and resistance R 6 should satisfy condition: R6*VDD/ (R1+R5+R6)＜0.7V, and R6*VDD1/ (R5+R6)〉0.7V, resistance R 8=1K, R2=100K, resistance R 1 is used the resistance in tens Europe, the upper current limit that the selective basis circuit of the 3rd switch element 23 is used is come fixed.
The operation principle of this overvoltage crowbar is:
suppose that the overvoltage protection voltage that needs to set is VDD1, as input voltage VDD during lower than the overvoltage protection voltage VDD1 that sets, the reference utmost point R end input voltage of three-terminal voltage-stabilizing pipe 11 is lower than 2.5V, internal reference voltage lower than three-terminal voltage-stabilizing pipe 11, 11 cut-offs of three-terminal voltage-stabilizing pipe, due to the first current-limiting resistance R1, the selection of resistance R 5 and resistance R 6 meets, R6*VDD/ (R1+R5+R6)＜0.7V, therefore make the first switch element 21 cut-offs, input power VDD provides conducting voltage for second switch element 22 after by the 3rd current-limiting resistance R9, make 22 conductings of second switch element, thereby drag down the first end of second switch element 22, namely drag down the control end of the 3rd switch element 23, namely drag down the voltage of the control end of P type metal-oxide-semiconductor, make P type metal-oxide-semiconductor meet turn-on condition, the conducting of P type metal-oxide-semiconductor, thereby make voltage output end output voltage VO UT=VDD, output voltage V DD powers to the postorder power circuit.
And when input voltage VDD meets or exceeds the overvoltage protection voltage VDD1 of setting; the reference edge R input voltage of three-terminal voltage-stabilizing pipe 11 meets or exceeds 2.5V; meet or exceed the internal reference voltage of three-terminal voltage-stabilizing pipe 11; operation principle according to three-terminal voltage-stabilizing pipe 11; when the TL431 voltage-stabiliser tube uses as adjustable stabilized voltage supply; it is output as 2.5V* (R4+R3)/R4; again due to VDD1*R4/ (R4+R3)=2.5V, so the voltage stabilization of the negative electrode K of three-terminal voltage-stabilizing pipe 11 end is at overvoltage protection voltage VDD1.Due to R6*VDD1/ (R5+R6)〉0.7V, therefore, the first switch element 21 conductings, the first switch element 21 conductings drag down the first end of the first switch element 21, also just dragged down the control end of second switch element 22, thereby made 22 cut-offs of second switch element, the control end that makes the 3rd switch element 23 is input supply voltage VDD, make the 3rd switch element 23 cut-offs, the output voltage VO of breaking UT.Thereby avoid too high input voltage VDD to cause damage to the components and parts in the postorder power circuit, played the effect of overvoltage protection.
In other embodiment of the present utility model, the three-terminal voltage-stabilizing pipe can be also other three-terminal voltage-stabilizing pipes of TL43 series, TL432 voltage-stabiliser tube for example, and wherein the internal reference voltage of TL432 voltage-stabiliser tube is 1.25V.
Overvoltage crowbar of the present utility model, adopted the three-terminal voltage-stabilizing pipe to realize the overvoltage protection of power circuit, without the OVP integrated chip, simple in structure, cost is low.And, due to the value of the first divider resistance by adjusting two series connection,, namely by the value of adjusting resistance R3 and resistance R 4, can adjust the set point VDD1 of overvoltage protection voltage.Therefore the overvoltage protection magnitude of voltage can be set according to actual needs easily.
The above is giving an example of the utility model preferred forms, and the part of wherein not addressing in detail is those of ordinary skills' common practise.Protection range of the present utility model is as the criterion with the content of claim, and any equivalent transformation that carries out based on technology enlightenment of the present utility model, also within protection range of the present utility model.
Claims (8)
1. overvoltage crowbar, is characterized in that: comprise voltage-stabilized power supply circuit and switching circuit; Described voltage-stabilized power supply circuit comprises the three-terminal voltage-stabilizing pipe, the negative electrode of described three-terminal voltage-stabilizing pipe is electrically connected to input power by the first current-limiting resistance, the reference utmost point of described three-terminal voltage-stabilizing pipe is electrically connected to the common node of two that are electrically connected to described negative electrode the first divider resistances of connecting, the anode of described three-terminal voltage-stabilizing pipe and the end equal ground connection of described two the first divider resistances of connecting away from described three-terminal voltage-stabilizing tube cathode; The negative electrode of described three-terminal voltage-stabilizing pipe is electrically connected to described switching circuit.
2. overvoltage crowbar as claimed in claim 1, it is characterized in that: described switching circuit comprises the first switch element, second switch element and the 3rd switch element, and described the first switch element, described second switch element and described the 3rd switch element comprise respectively first end, the second end and be used for controlling the control end of described first end and described the second end conducting;
The control end of described the first switch element is electrically connected to the common node of two that are electrically connected to described three-terminal voltage-stabilizing tube cathode the second divider resistances of connecting, its control end also is connected with the second current-limiting resistance, its second end and the end equal ground connection of described two the second divider resistances of connecting away from described three-terminal voltage-stabilizing tube cathode, its first end is electrically connected to described input power by the 3rd current-limiting resistance, and its first end also is electrically connected to the control end of described second switch element;
The first end of described second switch element is electrically connected to described input power by the 4th current-limiting resistance, the second equal ground connection of end of its second end and described the first switch element, and its first end also is electrically connected to the control end of described the 3rd switch element;
The first end of described the 3rd switch element is electrically connected to described input power, and its second end is voltage output end.
3. overvoltage crowbar as claimed in claim 2, it is characterized in that: described the first switch element and described second switch element are the NPN triode, and its first end is collector electrode, and its second end is emitter, and its control end is base stage.
4. overvoltage crowbar as claimed in claim 3, it is characterized in that: described the 3rd switch element is P type metal-oxide-semiconductor, and its first end is source electrode, and its second end is drain electrode, and its control end is grid.
5. overvoltage crowbar as claimed in claim 4, it is characterized in that: the first divider resistance of described two series connection comprises resistance R 3 and the resistance R 4 of series connection, one end of resistance R 3 is electrically connected to the first current-limiting resistance R1, the other end of resistance R 3 is electrically connected to an end of resistance R 4, the equal ground connection of anode of the other end of resistance R 4 and described three-terminal voltage-stabilizing pipe; The second divider resistance of described two series connection comprises resistance R 5 and the resistance R 6 of series connection, one end of resistance R 5 is connected with the cathodic electricity of described three-terminal voltage-stabilizing pipe, the other end of resistance R 5 is electrically connected to an end of resistance R 6, the second equal ground connection of end of the second end of the other end of resistance R 6 and the first switch element and second switch element.
6. overvoltage crowbar as claimed in claim 5, is characterized in that, the first current-limiting resistance R1, resistance R 3, resistance R 4, resistance R 5 and resistance R 6 need meet the following conditions:
VDD1*R4/(R4+R3)=Vref,R6*VDD/(R1+R5+R6)<0.7V，
And R6*VDD1/ (R5+R6)〉0.7V; Wherein, VDD is the voltage of input power, and VDD1 is overvoltage protection voltage, and Vref is the reference voltage of three-terminal voltage-stabilizing pipe.
7. overvoltage crowbar as described in any one in claim 1 to 6, is characterized in that, described three-terminal voltage-stabilizing pipe is TL43 series.
8. overvoltage crowbar as claimed in claim 7, is characterized in that, described three-terminal voltage-stabilizing pipe is TL431 voltage-stabiliser tube or TL432 voltage-stabiliser tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013203220466U CN203289075U (en) | 2013-06-05 | 2013-06-05 | Overvoltage protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013203220466U CN203289075U (en) | 2013-06-05 | 2013-06-05 | Overvoltage protection circuit |
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| CN203289075U true CN203289075U (en) | 2013-11-13 |
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| CN2013203220466U Expired - Lifetime CN203289075U (en) | 2013-06-05 | 2013-06-05 | Overvoltage protection circuit |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103280765A (en) * | 2013-06-05 | 2013-09-04 | 青岛歌尔声学科技有限公司 | Overvoltage protection circuit |
| CN103645359A (en) * | 2013-12-25 | 2014-03-19 | 上海神开石油化工装备股份有限公司 | Digital display meter overload protection device |
| CN106817026A (en) * | 2015-11-27 | 2017-06-09 | 亚荣源科技（深圳）有限公司 | The assists winding electric supply installation of automatic switchover |
-
2013
- 2013-06-05 CN CN2013203220466U patent/CN203289075U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103280765A (en) * | 2013-06-05 | 2013-09-04 | 青岛歌尔声学科技有限公司 | Overvoltage protection circuit |
| CN103645359A (en) * | 2013-12-25 | 2014-03-19 | 上海神开石油化工装备股份有限公司 | Digital display meter overload protection device |
| CN106817026A (en) * | 2015-11-27 | 2017-06-09 | 亚荣源科技（深圳）有限公司 | The assists winding electric supply installation of automatic switchover |
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| CX01 | Expiry of patent term |
Granted publication date: 20131113 |
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| CX01 | Expiry of patent term |