CN103050964A - Reverse voltage protection device - Google Patents
Reverse voltage protection device Download PDFInfo
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- CN103050964A CN103050964A CN2011103078574A CN201110307857A CN103050964A CN 103050964 A CN103050964 A CN 103050964A CN 2011103078574 A CN2011103078574 A CN 2011103078574A CN 201110307857 A CN201110307857 A CN 201110307857A CN 103050964 A CN103050964 A CN 103050964A
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- voltage
- protection device
- voltage protection
- reverse voltage
- raceway groove
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Abstract
The invention discloses a reverse voltage protection device which comprises an input end, an output end and a control end. The reverse voltage protection device is characterized in that the input end and the output end are serially connected between a direct current power supply and a fan circuit, or serially connected between the fan circuit and a grounding point. When the reverse voltage protection device is connected between the direct current power supply and the fan circuit, the reverse voltage protection device comprises a PMOSFET (P-channel Metal-Oxide-Semiconductor Field-Effect Transistor), a drain electrode, a source electrode and a grid electrode of the PMOSFET are respectively and sequentially connected with the input end, the output end and the control end, and the control end is connected with a low-reference level voltage; and when the reverse voltage protection device is connected between the fan circuit and the grounding point, the reverse voltage protection device comprises an NMOSFET(N-channel Metal-Oxide-Semiconductor Field-Effect Transistor), a source electrode, a drain electrode and a grid electrode of the NMOSFET are respectively and sequentially connected with the input end, the output end and the control end, and the control end is connected with a high-reference level voltage. Compared with the existing reverse voltage protection device formed by a diode, the reverse voltage protection device has the characteristics of low break-over voltage, low loop loss and low part temperature rise.
Description
Technical field
The present invention is about a kind of voltage protection, in particular for being electrically connected between a direct current power supply and the fan circuit, in case the non-return a kind of reverse voltage protection device that is entered and destroyed this fan circuit to voltage by this DC power supply.
Background technology
Please refer to shown in Figure 1ly, it is a kind of circuit diagram of existing reverse voltage protection device.This reverse voltage protection device 7 is for being connected in series between a direct current power supply 8 and the fan circuit 9, and has an input 71 and be connected in this DC power supply 8, and has an output 72 and be connected in this fan circuit 9; In addition, this DC power supply 8 has a positive voltage terminal 81 and a negative voltage side 82, and this positive voltage terminal 81 connects this input 71, and this negative voltage side 82 is ground connection then.In detail, this reverse voltage protection device 7 is made of a diode, and wherein the anode of this diode consists of the input 71 of this reverse voltage protection device 7, and the negative electrode of this diode then consists of the output 72 of this reverse voltage protection device 7.By the reverse voltage protection device 7 with above-mentioned connected mode, the voltage of exporting when the positive voltage terminal 81 of this DC power supply 8 makes the voltage of this input 71 be higher than the voltage of this output 72, and the voltage difference between this input 71 and this output 72 is during greater than the cut-in voltage (junction potential barrier) of this diode, and the electric power that this DC power supply 8 is exported can be by this reverse voltage protection device 7 these fan circuits 8 of input; Otherwise; if the voltage that the positive voltage terminal 81 of this DC power supply 8 is exported can't make the voltage difference of this input 71 and this output 72 greater than the cut-in voltage of this diode; then the electric power of this DC power supply 8 can suffer that just this reverse voltage protection device 7 stops, can't be sent to this fan circuit 9.
Yet; in the situation of normal operation; because above-mentioned existing reverse voltage protection device 7 is made of diode; and the cut-in voltage of general diode (for example Schottky diode, fast diode or free-wheel diode) is about 0.5 to 0.6V; and the conducting voltage (i.e. voltage difference between this input 71 and this output 72) of wanting this diode of conducting need be higher than this cut-in voltage at least; therefore cause this DC power supply 8 that higher conducting voltage need to be provided, could be to pass through this this fan circuit 9 of reverse voltage protection device 7 driven.In addition; owing to there is this cut-in voltage; the electric current of the every output of the positive voltage terminal 81 of this DC power supply 8 1A by this reverse voltage protection device 7 to this fan circuit 9, just can be in about 0.5 to 0.6W the electrical power of these reverse voltage protection device 7 additive decrementations, thereby cause the consume of high loop.
For these reasons, be necessary further to improve above-mentioned existing reverse voltage protection device, in the hope of having the effect of low conducting voltage and the consume of low loop.
Summary of the invention
Main purpose of the present invention provides a kind of reverse voltage protection device, comprises a PMOS or a NMOS, in order to have the effect of low conducting voltage, the consume of low loop and low part temperature rise.
A kind of reverse voltage protection device provided by the invention, it comprises: an input connects a DC power supply; An output connects a fan circuit; And a control end connects a low level voltage; Wherein has in addition a p raceway groove metal-oxide half field effect transistor, the drain electrode of this p raceway groove metal-oxide half field effect transistor connects this input, the source electrode of this p raceway groove metal-oxide half field effect transistor connects this output, and the grid of this p raceway groove metal-oxide half field effect transistor connects this control end.
The voltage difference of aforementioned low level voltage and this DC power supply is more than or equal to a lower bound magnitude of voltage, and this lower bound magnitude of voltage is the summation of cut-in voltage of the parasitic diode of the critical voltage of this p raceway groove metal-oxide half field effect transistor and this p raceway groove metal-oxide half field effect transistor.
Another kind of reverse voltage protection device provided by the invention, it comprises: an input is connected to a DC power supply by a fan circuit; An output connects an earth point; And a control end connects a high levle voltage; Wherein has in addition a n raceway groove metal-oxide half field effect transistor, the source electrode of this n raceway groove metal-oxide half field effect transistor connects this input, the drain electrode of this n raceway groove metal-oxide half field effect transistor connects this output, and the grid of this n raceway groove metal-oxide half field effect transistor connects this control end.
The voltage difference of aforementioned high levle voltage and this earth point is more than or equal to a lower bound magnitude of voltage, and this lower bound magnitude of voltage is the summation of cut-in voltage of the parasitic diode of the critical voltage of this n raceway groove metal-oxide half field effect transistor and this n raceway groove metal-oxide half field effect transistor.
Beneficial effect of the present invention is: the reverse voltage protection device that consists of by the PMOS that is connected between this DC power supply and this fan circuit; or be connected in the reverse voltage protection device that the NMOS between this fan circuit and this earth point consists of; reverse voltage protection device of the present invention can utilize the parasitic diode of this PMOS or NMOS to judge when voltage is just inputted whether this voltage is positive voltage; and after this PMOS forms p carrier raceway groove or NMOS formation n carrier raceway groove; namely with this raceway groove as the current delivery path, so can have low conducting voltage compared to the existing reverse voltage protection device that consists of with diode; the characteristic of the consume of low loop and low part temperature rise.
Description of drawings
Fig. 1: the circuit diagram of existing reverse voltage protection device.
Fig. 2: the circuit diagram of the first embodiment of reverse voltage protection device of the present invention.
Fig. 3: the circuit diagram of the second embodiment of reverse voltage protection device of the present invention.
[primary clustering symbol description]
(the present invention)
1 reverse voltage protection device, 11 inputs
12 outputs, 13 control ends
2 reverse voltage protection devices, 21 inputs
22 outputs, 23 control ends
8 DC power supply, 81 positive voltage terminals
82 negative voltage sides
9 fan circuits, 91 power input ends
92 earth terminals
D1 parasitic diode d2 parasitic diode
(prior art)
7 reverse voltage protection devices, 71 inputs
72 outputs
Embodiment
For above-mentioned and other purpose, feature and advantage of the present invention can be become apparent, preferred embodiment of the present invention cited below particularly, and cooperate appended graphicly, be described in detail below:
Please refer to shown in Figure 2; it illustrates the circuit diagram of the first embodiment of reverse voltage protection device of the present invention; wherein the reverse voltage protection device 1 of present embodiment comprises a p raceway groove metal-oxide half field effect transistor (PMOSFET; hereinafter to be referred as PMOS); goodly only consisted of by this PMOS, and this reverse voltage protection device 1 is connected in series between a direct current power supply 8 and the fan circuit 9.
Referring again to shown in Figure 2, this reverse voltage protection device 1 has an input 11, an output 12 and a control end 13.This input 11 is for the positive voltage terminal 81 that connects this DC power supply 8; This output 12 is for the power input end 91 that connects this fan circuit 9; 13 confessions of this control end are connected to a low level voltage, and wherein the voltage quasi position of this low level voltage is lower than the voltage quasi position of positive voltage terminal 81 in the normal power supply situation of this DC power supply 8.In detail, when this reverse voltage protection device 1 is a PMOS, this input 11 connects the drain electrode (drain) of this PMOS, this output 12 connects the source electrode (source) of this PMOS, this control end 13 then connects the grid (gate) of this PMOS, wherein this positive voltage terminal 81 and the voltage difference of this low level voltage be more than or equal to a lower bound magnitude of voltage, the summation of parasitic diode (body diode) the d1 cut-in voltage of the critical voltage that this lower bound magnitude of voltage be this PMOS (threshold voltage) and this PMOS; Also namely, the source electrode of this PMOS is for the power input end 91 that connects this fan circuit 9, and the drain electrode of this PMOS is then for the positive voltage terminal 81 that connects this DC power supply 8.
When operating; when the positive voltage terminal 81 of this DC power supply 8 has just begun to supply power to this reverse voltage protection device 1; the electric power of this positive voltage terminal 81 will be sent to by this parasitic diode d1 the power input end 91 of this fan circuit 9; and make this power input end 91 deduct the cut-in voltage of this parasitic diode d1 for the magnitude of voltage of this positive voltage terminal 81 at the magnitude of voltage of this moment; therefore the voltage difference of this power input end 91 and this low level voltage is more than or equal to the critical voltage (namely the voltage difference of the source electrode of this PMOS and grid is more than or equal to this critical voltage) of this PMOS; so can between the drain electrode of this PMOS and source electrode, form a p carrier raceway groove, make between this input 11 and the output 12 to be conducting state by this p carrier raceway groove.Subsequently, in case this p carrier raceway groove forms, have much smaller than the impedance of this parasitic diode d1 owing to being bordering on short circuit between this input 11 and the output 12, so the electric power of this positive voltage terminal 81 just is sent to this fan circuit 9 via this p carrier raceway groove.Wherein, because this reverse voltage protection device 1 only need to provide voltage more than or equal to this lower bound magnitude of voltage by this positive voltage terminal 81 when just beginning to power; the voltage difference that only needs to have more than or equal to this critical voltage between maintenance and this low level voltage after forming this p carrier raceway groove gets final product, so this reverse voltage protection device 1 has the characteristic of low conducting voltage.In addition; because after forming this p carrier raceway groove; conduction resistance value between this input 11 and the output 12 only is about 0.018 ohm; therefore when the electric current of this positive voltage terminal 81 output 1A passes through this reverse voltage protection device 1 to this fan circuit 9; only can consume the electrical power of about 0.018W at this reverse voltage protection device 1, so also have the consume of low loop.In addition, because this reverse voltage protection device 1 itself only has extremely low electric power consumption, therefore have more the characteristic of low part temperature rise.
Otherwise; when just beginning to power; if 81 runnings of the positive voltage terminal of this DC power supply 8 are unusual; if perhaps this DC power supply 8 of the careless reversal connection of user and this negative voltage side 82 is connected to this input 11; cause the voltage of this input 11 to be lower than this lower bound magnitude of voltage and can't this parasitic diode of conducting d1, thereby the voltage difference (i.e. the voltage difference of the source electrode of this PMOS and grid) of output 12 voltages and control end 13 voltages that makes this reverse voltage protection device 1 is less than the critical voltage of this PMOS.Therefore, be not conducting state between this input 11 and the output 12, can avoid backward current to pass through this fan circuit 9, reach the purpose of revers voltage protection.
Please refer to shown in Figure 3; it illustrates the circuit diagram of the second embodiment of reverse voltage protection device of the present invention; wherein the reverse voltage protection device 2 of present embodiment comprises a n raceway groove metal-oxide half field effect transistor (NMOSFET; hereinafter to be referred as NMOS); goodly only consisted of by this NMOS, and this reverse voltage protection device 2 is connected in series between a fan circuit 9 and the earth point.
In detail, this reverse voltage protection device 2 has an input 21, an output 22 and a control end 23.This input 21 is for the earth terminal 92 that connects this fan circuit 9; This output 22 is for connecting this earth point; This control end 23 then confession is connected to a high levle voltage, and wherein the voltage quasi position of this high levle voltage is higher than the voltage quasi position of this earth point.In addition, when this reverse voltage protection device 2 is a NMOS, this input 21 connects the source electrode of this NMOS, this output 22 connects the drain electrode of this NMOS, this control end 23 then connects the grid of this NMOS, wherein the voltage difference of this high levle voltage and this earth point is more than or equal to another lower bound magnitude of voltage, the summation of the critical voltage that this another lower bound magnitude of voltage is this NMOS and the parasitic diode d2 cut-in voltage of this NMOS; Also namely, the source electrode of this NMOS is for the earth terminal 92 that connects this fan circuit 9, and the drain electrode of this NMOS is then for connecting this earth point.
When operating; when the positive voltage terminal 81 of this DC power supply 8 has just begun to supply power to this reverse voltage protection device 2 by this fan circuit 9; the electric power of this positive voltage terminal 81 will be sent to this earth point by this parasitic diode d2 and form a loop; and make this earth terminal 92 only be the cut-in voltage of this parasitic diode d2 at the magnitude of voltage of this moment; therefore the voltage difference of this low level voltage and this earth terminal 92 is more than or equal to the critical voltage (namely the voltage difference of the source electrode of this NMOS and grid is more than or equal to this critical voltage) of this NMOS; so can between the drain electrode of this NMOS and source electrode, form a n carrier raceway groove, make between this input 21 and the output 22 to be conducting state by this n carrier raceway groove.Subsequently; in case this n carrier raceway groove forms; have much smaller than the impedance of this parasitic diode d2 owing to being bordering on short circuit between this input 21 and the output 22, so the electric power of this positive voltage terminal 81 just can be sequentially is sent to this earth point via the n carrier raceway groove of this fan circuit 9 and this reverse voltage protection device 2.In like manner, the reverse voltage protection device 2 that is made of this NMOS also can have the characteristic of low conducting voltage, the consume of low loop and low part temperature rise.
Otherwise; when just beginning to power; if 81 runnings of the positive voltage terminal of this DC power supply 8 are unusual; if perhaps this DC power supply 8 of the careless reversal connection of user and this negative voltage side 82 is connected to the power input end 91 of this fan circuit 9; cause the voltage of this input 21 to be lower than this lower bound magnitude of voltage and can't this parasitic diode of conducting d2, thereby the voltage difference (i.e. the voltage difference of the source electrode of this NMOS and grid) of input 21 voltages and control end 23 voltages that makes this reverse voltage protection device 2 is less than the critical voltage of this NMOS.Therefore, be not conducting state between this input 21 and the output 22, can avoid backward current to pass through this fan circuit 9, reach the purpose of revers voltage protection.
In sum; the reverse voltage protection device 1 that consists of by the PMOS that is connected between this DC power supply 8 and this fan circuit 9; or be connected in the reverse voltage protection device 2 that the NMOS between this fan circuit 9 and this earth point consists of; reverse voltage protection device of the present invention can utilize the parasitic diode d1 of this PMOS or NMOS; d2 judges when voltage is just inputted whether this voltage is positive voltage; and after this PMOS forms p carrier raceway groove or NMOS formation n carrier raceway groove; namely with this raceway groove as the current delivery path, so can have low conducting voltage compared to the existing reverse voltage protection device that consists of with diode; the characteristic of the consume of low loop and low part temperature rise.
Claims (4)
1. reverse voltage protection device is characterized in that it comprises:
An input connects a DC power supply;
An output connects a fan circuit; And
A control end connects a low level voltage;
Wherein has in addition a p raceway groove metal-oxide half field effect transistor, the drain electrode of this p raceway groove metal-oxide half field effect transistor connects this input, the source electrode of this p raceway groove metal-oxide half field effect transistor connects this output, and the grid of this p raceway groove metal-oxide half field effect transistor connects this control end.
2. reverse voltage protection device as claimed in claim 1; it is characterized in that; the voltage difference of this low level voltage and this DC power supply is more than or equal to a lower bound magnitude of voltage, and this lower bound magnitude of voltage is the summation of cut-in voltage of the parasitic diode of the critical voltage of this p raceway groove metal-oxide half field effect transistor and this p raceway groove metal-oxide half field effect transistor.
3. reverse voltage protection device is characterized in that it comprises:
An input is connected to a DC power supply by a fan circuit;
An output connects an earth point; And
A control end connects a high levle voltage;
Wherein has in addition a n raceway groove metal-oxide half field effect transistor, the source electrode of this n raceway groove metal-oxide half field effect transistor connects this input, the drain electrode of this n raceway groove metal-oxide half field effect transistor connects this output, and the grid of this n raceway groove metal-oxide half field effect transistor connects this control end.
4. reverse voltage protection device as claimed in claim 3; it is characterized in that; the voltage difference of this high levle voltage and this earth point is more than or equal to a lower bound magnitude of voltage, and this lower bound magnitude of voltage is the summation of cut-in voltage of the parasitic diode of the critical voltage of this n raceway groove metal-oxide half field effect transistor and this n raceway groove metal-oxide half field effect transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103078574A CN103050964A (en) | 2011-10-12 | 2011-10-12 | Reverse voltage protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103078574A CN103050964A (en) | 2011-10-12 | 2011-10-12 | Reverse voltage protection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103050964A true CN103050964A (en) | 2013-04-17 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011103078574A Pending CN103050964A (en) | 2011-10-12 | 2011-10-12 | Reverse voltage protection device |
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5519557A (en) * | 1993-11-19 | 1996-05-21 | Chrysler Corporation | Power supply polarity reversal protection circuit |
| US6043965A (en) * | 1997-11-20 | 2000-03-28 | General Motors Corporation | Low loss reverse battery protection |
| US20020141124A1 (en) * | 2001-04-02 | 2002-10-03 | Masayasu Ito | Protection device |
| CN101656418A (en) * | 2008-08-20 | 2010-02-24 | 台达电子工业股份有限公司 | Fan system and power reverse protection device thereof |
| CN201570860U (en) * | 2009-11-06 | 2010-09-01 | 深圳市同洲电子股份有限公司 | Direct current power circuit with reverse polarity protective function |
| CN101872971A (en) * | 2010-07-02 | 2010-10-27 | 北京星网锐捷网络技术有限公司 | Reverse-connection preventing circuit, reverse-connection preventing processing method and communication equipment |
| CN102136724A (en) * | 2011-01-26 | 2011-07-27 | 华为技术有限公司 | Method and device for protecting reverse connection prevention and slow start of direct-current power supply input |
| CN201994659U (en) * | 2011-04-22 | 2011-09-28 | 北京科诺伟业科技有限公司 | Reverse-connection-prevention protective circuit for solar photovoltaic charging controller |
| CN202260444U (en) * | 2011-10-12 | 2012-05-30 | 昆山广兴电子有限公司 | Reverse voltage protection device |
-
2011
- 2011-10-12 CN CN2011103078574A patent/CN103050964A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5519557A (en) * | 1993-11-19 | 1996-05-21 | Chrysler Corporation | Power supply polarity reversal protection circuit |
| US6043965A (en) * | 1997-11-20 | 2000-03-28 | General Motors Corporation | Low loss reverse battery protection |
| US20020141124A1 (en) * | 2001-04-02 | 2002-10-03 | Masayasu Ito | Protection device |
| CN101656418A (en) * | 2008-08-20 | 2010-02-24 | 台达电子工业股份有限公司 | Fan system and power reverse protection device thereof |
| CN201570860U (en) * | 2009-11-06 | 2010-09-01 | 深圳市同洲电子股份有限公司 | Direct current power circuit with reverse polarity protective function |
| CN101872971A (en) * | 2010-07-02 | 2010-10-27 | 北京星网锐捷网络技术有限公司 | Reverse-connection preventing circuit, reverse-connection preventing processing method and communication equipment |
| CN102136724A (en) * | 2011-01-26 | 2011-07-27 | 华为技术有限公司 | Method and device for protecting reverse connection prevention and slow start of direct-current power supply input |
| CN201994659U (en) * | 2011-04-22 | 2011-09-28 | 北京科诺伟业科技有限公司 | Reverse-connection-prevention protective circuit for solar photovoltaic charging controller |
| CN202260444U (en) * | 2011-10-12 | 2012-05-30 | 昆山广兴电子有限公司 | Reverse voltage protection device |
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Application publication date: 20130417 |