CN201860257U - Input overvoltage protection circuit - Google Patents
Input overvoltage protection circuit Download PDFInfo
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- CN201860257U CN201860257U CN2010205904283U CN201020590428U CN201860257U CN 201860257 U CN201860257 U CN 201860257U CN 2010205904283 U CN2010205904283 U CN 2010205904283U CN 201020590428 U CN201020590428 U CN 201020590428U CN 201860257 U CN201860257 U CN 201860257U
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Abstract
The utility model discloses an input overvoltage protection circuit which comprises the following components: a voltage detector, a first capacitor, a second capacitor, a first switch and a second switch. A DC input voltage which is received by a power supply after AC power supply rectification is detected through a voltage detector. When the DC input voltage exceeds a threshold, a voltage detector outputs a switch signal for causing no conduction of the first switch and conduction of the second switch. The first capacitor and the second capacitor which provide serial coupling are used as input filter capacitors. When the DC input voltage does not exceed the threshold, the voltage detector does not output switching signal so the first switch is conducted and the second switch is not conducted for supplying the first capacitor as an input filtering capacitor. Thereby the input filter capacitors with different voltage resistances are automatically supplied according to different AC power supply voltage received by the power supply, and an effect of input overvoltage protection is obtained with a lower cost.
Description
Technical field
The utility model is about a kind of input excess voltage protection, and particularly a kind of input excess voltage protection that is used for power supply unit.
Background technology
Fig. 1 is a kind of circuit diagram of existing power supply unit.See also Fig. 1, power supply unit 1 comprises Electromagnetic interference filter 11, bridge rectifier 12, input filter condenser 13, DC-DC converter 14 and output filter capacitor 15.After the AC power Vac input,, convert DC input voitage Vin to by the rectification of bridge rectifier 12 and the filtering of input filter condenser 13 again by Electromagnetic interference filter 11 filtering noises.The DC input voitage Vin of tool adjustment property does not convert the VD Vout that tool is adjusted property to by the conversion of DC-DC converter 14 and the filtering of output filter capacitor 15.
When power supply unit 1 is designed for the AC power Vac that receives low voltage (as 110Vrms), the input filter condenser 13 that adopts withstand voltage lower, if because of carelessness its ac plug is inserted the socket of the AC power Vac that is used to provide high voltage (as 220Vrms) when using, then input filter condenser 13 will be because of withstand voltage not enough and on fire from explosion.Certainly, power supply unit 1 can adopt withstand voltage higher input filter condenser 13 to prevent because of withstand voltage not enough and on fire from explosion, but its cost is higher certainly.
Summary of the invention
The purpose of this utility model is to provide a kind of input excess voltage protection exactly, and the difference of the AC supply voltage that can receive according to power supply unit provides different withstand voltage input filter condensers automatically.
The utility model proposes a kind of input excess voltage protection, it has first end and second end and coupled in parallel to receive DC input voitage.The input excess voltage protection comprises voltage detector, first capacitor, first switch, second capacitor and second switch; wherein voltage detector has first end, second end and output; first capacitor and second capacitor all have first end and second end, and first switch and second switch all have first end, second end and control end.First end of voltage detector and second end couple first end and second end of input excess voltage protection respectively, and the output of voltage detector is the output switching signal when DC input voitage surpasses threshold value.First end of first capacitor couples first end of input excess voltage protection.First end of first switch, second end and control end couple second end of first capacitor, second end of input excess voltage protection and the output of voltage detector, the first not conducting of switch when receiving switching signal respectively.First end of second capacitor couples second end of first capacitor.First end of second switch, second end and control end couple second end of second capacitor, second end of input excess voltage protection and the output of voltage detector, second switch conducting when receiving switching signal respectively.
The utility model is because of adopting the difference according to the DC input voitage after the AC power rectification of power supply unit reception; first and second capacitors (it is higher that it is withstand voltage) that automatically switch into first capacitor (it is lower that it is withstand voltage) or coupled in series are to provide as different withstand voltage input filter condensers; can prevent because of withstand voltage not enough and on fire from explosion, reach the effect of input overvoltage protection with lower cost.
For above-mentioned and other purposes, feature and advantage of the present utility model can be become apparent, preferred embodiment cited below particularly, and conjunction with figs. are described in detail below.
Description of drawings
Fig. 1 is a kind of circuit diagram of existing power supply unit;
Fig. 2 imports the circuit diagram of the power supply unit of excess voltage protection for adopting the utility model;
Fig. 3 is the circuit diagram of the utility model input excess voltage protection;
Fig. 4 is the circuit diagram of a preferred embodiment of the utility model input excess voltage protection.
Description of reference numerals: 1,2-power supply unit; 11,21-Electromagnetic interference filter; 12,22-bridge rectifier; The 13-input filter condenser; 14,24-DC-DC converter; 15,25-output filter capacitor; 23,43-input excess voltage protection; 231, first end of 431-input excess voltage protection; 232, second end of 432-input excess voltage protection; C1-first capacitor; C2-second capacitor; C3-the 3rd capacitor; The DET-voltage detector; First end of IN1-voltage detector; Second end of IN2-voltage detector; The output of OUT-voltage detector; The Dz1-Zener diode; Q1, Q3-N channel fet; The Q2-P channel fet; The R1-resistor; Rb1-first bias resistor; Rb2-second bias resistor; The Re1-first grading resistor device; The Re2-second grading resistor device; Rs1-first detects resistor; Rs2-second detects resistor; S1-first switch; The S2-second switch; S3-the 3rd switch; The Vac-AC power; The Vin-DC input voitage; The Vout-VD.
Embodiment
Fig. 2 imports the circuit diagram of the power supply unit of excess voltage protection for adopting the utility model.See also Fig. 2, power supply unit 2 comprises Electromagnetic interference filter 21, bridge rectifier 22, input excess voltage protection 23, DC-DC converter 24 and output filter capacitor 25.After the AC power Vac input,, convert DC input voitage Vin to by the rectification of bridge rectifier 22 and the filtering of input excess voltage protection 23 again by Electromagnetic interference filter 21 filtering noises.The DC input voitage Vin of tool adjustment property does not convert the VD Vout that tool is adjusted property to by the conversion of DC-DC converter 24 and the filtering of output filter capacitor 25.The difference of the AC power Vac voltage that input excess voltage protection 23 can receive according to power supply unit 2 provides different withstand voltage input filter condensers automatically, reaches the effect of input overvoltage protection at lower cost.
Fig. 3 is the circuit diagram of the utility model input excess voltage protection.See also Fig. 3, input excess voltage protection 23 have first end 231 and second end 232 and coupled in parallel to the output of bridge rectifier 22 as shown in Figure 2 to receive DC input voitage Vin.Input excess voltage protection 23 comprises voltage detector DET, the first capacitor C1, first switch S 1, the second capacitor C2 and second switch S2; wherein voltage detector DET has the first end IN1, the second end IN2 and output OUT; the first capacitor C1 and the second capacitor C2 all have first end and second end, and first switch S 1 and second switch S2 all have first end, second end and control end.
The first end IN1 of voltage detector DET and the second end IN2 couple first end 231 and second end 232 of input excess voltage protection 23 respectively, and the output OUT of voltage detector DET is the output switching signal when DC input voitage Vin surpasses threshold value; Otherwise, when DC input voitage Vin does not surpass threshold value, do not export switching signal certainly.First end of the first capacitor C1 couples first end 231 of input excess voltage protection 23.First end of first switch S 1, second end and control end couple second end of the first capacitor C1, second end 232 of input excess voltage protection 23 and the output OUT of voltage detector DET, first switch S, 1 not conducting when receiving switching signal respectively; Otherwise, first switch S, 1 certain conducting when not receiving switching signal.First end of the second capacitor C2 couples second end of the first capacitor C1.First end of second switch S2, second end and control end couple second end of the second capacitor C2, second end 232 of input excess voltage protection 23 and the output OUT of voltage detector DET, second switch S2 conducting when receiving switching signal respectively; Otherwise, second switch S2 not conducting certainly when not receiving switching signal.
Higher and when making DC input voitage Vin surpass threshold value at AC power Vac voltage; the output OUT output switching signal of voltage detector DET; make 1 not conducting of first switch S and second switch S2 conducting; this moment, the first capacitor C1 and the second capacitor C2 coupled in series were between first end 231 of input excess voltage protection 23 and second end 232 and as input filter condenser, it is higher that it is withstand voltage.Lower and when making DC input voitage Vin surpass threshold value at AC power Vac voltage; the output OUT of voltage detector DET does not export switching signal; make 1 conducting of first switch S and not conducting of second switch S2; this moment, only the first capacitor C 1 was coupled between input first end 231 of excess voltage protection 23 and second end 232 and as input filter condenser, it is lower that it is withstand voltage.
Fig. 4 is the circuit diagram of a preferred embodiment of the utility model input excess voltage protection.See also Fig. 4, input excess voltage protection 43 has first end 431 and second end 432 and coupled in parallel to receive DC input voitage Vin.Input excess voltage protection 43 comprises voltage detector DET, the first capacitor C1, first switch S 1, the second capacitor C2 and second switch S2; wherein voltage detector DET has the first end IN1, the second end IN2 and output OUT; the first capacitor C1 and the second capacitor C2 all have first end and second end, and first switch S 1 and second switch S2 all have first end, second end and control end.
Input excess voltage protection 43 also comprises the first grading resistor device Re1 and the second grading resistor device Re2, and wherein the first grading resistor device Re1 and the second grading resistor device Re2 all have first end and second end.First end of the first grading resistor device Re1 and second end couple first end and second end of the first capacitor C1 respectively.First end of the second grading resistor device Re2 and second end couple first end and second end of the second capacitor C2 respectively.The first grading resistor device Re1 and the second grading resistor device Re2 are used to make the voltage equalization that drops on the first capacitor C1 and the second capacitor C2, preventing that voltage is unequal causes the overtension that drops on a certain capacitor and breakdown, and then makes another capacitor very fast also breakdown.
In the present embodiment, first switch S 1 comprises N channel fet Q1, and this N channel fet Q1 has drain electrode end, source terminal and gate terminal and couples first end, second end and the control end of first switch S 1 respectively.Second switch S2 comprises P channel fet Q2, and this P channel fet Q2 has source terminal, drain electrode end and gate terminal and couples first end, second end and the control end of second switch S2 respectively.At this moment, input excess voltage protection 43 also comprises the first bias resistor Rb1 and the second bias resistor Rb2, and wherein the first bias resistor Rb1 and the second bias resistor Rb2 all have first end and second end.First end of the first bias resistor Rb1 and second end couple first end 431 of input excess voltage protection 43 and the output OUT of voltage detector DET respectively.First end of the second bias resistor Rb2 and second end couple second end of the first bias resistor Rb1 and second end 432 of input excess voltage protection 43 respectively.The first bias resistor Rb1 and the second bias resistor Rb2 are used for when the output OUT of voltage detector DET does not export switching signal, provide bias voltage to make Q1 conducting of N channel fet and not conducting of P channel fet Q2.
In the present embodiment, voltage detector DET comprises that first detects resistor R s1, the second detection resistor R s2, Zener diode Dz1, the 3rd capacitor C3, resistor R 1 and the 3rd switch S 3, wherein the first detection resistor R s1, the second detection resistor R s2, the 3rd capacitor C3 and resistor R 1 all have first end and second end, Zener diode Dz1 has cathode terminal and anode tap, and the 3rd switch S 3 has first end, second end and control end.First first end that detects resistor R s1 couples the first end IN1 of voltage detector DET.Second first end and second end that detects resistor R s2 couples second end of the first detection resistor R s1 and the second end IN2 of voltage detector DET respectively.The cathode terminal of Zener diode Dz1 couples first end of the second detection resistor R s2.First end of the 3rd capacitor C3 and second end couple the anode tap of Zener diode Dz1 and the second end IN2 of voltage detector DET respectively.First end of resistor R 1 and second end couple the anode tap of Zener diode Dz1 and the second end IN2 of voltage detector DET respectively.First end of the 3rd switch S 3, second end and control end couple the second end IN2 of output OUT, voltage detector DET of voltage detector DET and the anode tap of Zener diode Dz1 respectively, the 3rd switch S 3 conductings when DC input voitage Vin surpasses threshold value; Otherwise, the 3rd switch S 3 not conductings certainly when DC input voitage Vin does not surpass threshold value.In addition, the 3rd switch S 3 comprises N channel fet Q3, and this N channel fet Q3 has drain electrode end, source terminal and gate terminal and couples first end, second end and the control end of the 3rd switch S 3 respectively.
Wherein, the first detection resistor R s1 and the second detection resistor R s2 are used for DC input voitage Vin is carried out the dividing potential drop sampling.The 3rd capacitor C3 is used for when Zener diode Dz1 collapse conducting DC input voitage Vin being detected resistor R s1 by first and the second detection resistor R s2 voltage after partial is carried out filtering and voltage stabilizing.Resistor R 1 is used for when Zener diode Dz1 does not collapse the 3rd capacitor C3 discharged and provides second end 432 that gate terminal one path of N channel fet Q3 couples input excess voltage protection 43 and ground connection.
The utility model design is when DC input voitage Vin surpasses threshold value; DC input voitage Vin detects resistor R s1 by first and the second detection resistor R s2 voltage after partial can make Zener diode Dz1 collapse conducting and N channel fet Q3 conducting; the N channel fet Q3 of the output OUT of voltage detector DET by conducting couples second end 432 of input excess voltage protection 43 and ground connection; this moment, the output OUT of voltage detector DET exported switching signal (being the low level signal) because of ground connection, can make not conducting of Q1 of N channel field-effect transistor and P channel fet Q2 conducting.When DC input voitage Vin does not surpass threshold value, DC input voitage Vin detects resistor R s1 by first and the second detection resistor R s2 voltage after partial can't make Zener diode Dz1 collapse conducting, so not conducting of N channel fet Q3, this moment, the output OUT of voltage detector DET was equivalent to open circuit, provided bias voltage to make Q1 conducting of N channel fet and not conducting of P channel fet Q2 by the first bias resistor Rb1 and the second bias resistor Rb2.
In sum; the utility model input excess voltage protection detects DC input voitage after the AC power rectification that power supply unit receives by voltage detector; higher and when making DC input voitage surpass threshold value in AC supply voltage; voltage detector output switching signal; make the first not conducting of switch and second switch conducting; with first capacitor that coupled in series is provided and second capacitor as input filter condenser; it is higher that it is withstand voltage; lower and when making DC input voitage surpass threshold value in AC supply voltage; voltage detector is not exported switching signal; make first switch conduction and not conducting of second switch; to provide first capacitor as input filter condenser, it is lower that it is withstand voltage.Therefore; the utility model input excess voltage protection provides different withstand voltage input filter condensers automatically according to the difference of the AC supply voltage that power supply unit receives; can prevent because of withstand voltage not enough and on fire from explosion, reach the effect of input overvoltage protection with lower cost.
Though the utility model is open in above preferred embodiment; so it is not to be used for limiting the utility model; any those skilled in the art; in not breaking away from spirit and scope of the present utility model; when doing a few modifications and retouching, therefore protection range of the present utility model is as the criterion when looking accompanying the claim person of defining.
Claims (7)
1. an input excess voltage protection has one first end and one second end, and coupled in parallel is characterized in that to receive a direct current input voltage this input excess voltage protection comprises:
One voltage detector, have one first end, one second end and an output, first end of this voltage detector and second end couple first end and second end of this input excess voltage protection respectively, and signal is switched in the output one when this DC input voitage surpasses a threshold value of the output of this voltage detector;
One first capacitor, its first end couples first end of this input excess voltage protection;
One first switch, have one first end, one second end and a control end, couple second end of this first capacitor, second end of this input excess voltage protection and the output of this voltage detector respectively, this not conducting of first switch when receiving this switching signal;
One second capacitor, its first end couples second end of this first capacitor;
One second switch; have one first end, one second end and a control end; couple second end of this second capacitor, second end of this input excess voltage protection and the output of this voltage detector respectively, this second switch conducting when receiving this switching signal.
2. input excess voltage protection as claimed in claim 1 is characterized in that, described input excess voltage protection also comprises:
One first grading resistor device, its first end and second end couple first end and second end of this first capacitor respectively;
One second grading resistor device, its first end and second end couple first end and second end of this second capacitor respectively.
3. input excess voltage protection as claimed in claim 1; it is characterized in that; this first switch comprises a N channel fet, and the drain electrode end of this N channel fet, source terminal and gate terminal couple first end, second end and the control end of this first switch respectively.
4. input excess voltage protection as claimed in claim 1; it is characterized in that; this second switch comprises a P channel fet, and the source terminal of this P channel fet, drain electrode end and gate terminal couple first end, second end and the control end of this second switch respectively.
5. as claim 3 or 4 described input excess voltage protections, it is characterized in that described input excess voltage protection also comprises:
One first bias resistor, its first end and second end couple first end of this input excess voltage protection and the output of this voltage detector respectively;
One second bias resistor, its first end and second end couple second end of this first bias resistor and second end of this input excess voltage protection respectively.
6. input excess voltage protection as claimed in claim 1 is characterized in that, this voltage detector comprises:
One first detects resistor, and its first end couples first end of this voltage detector;
One second detects resistor, and its first end and second end couple second end of this first detection resistor and second end of this voltage detector respectively;
One Zener diode, its cathode terminal couple first end of this second detection resistor;
One the 3rd capacitor, its first end and second end couple the anode tap of this Zener diode and second end of this voltage detector respectively;
One resistor, its first end and second end couple the anode tap of this Zener diode and second end of this voltage detector respectively;
One the 3rd switch, have one first end, one second end and a control end, couple the output of this voltage detector, second end of this voltage detector and the anode tap of this Zener diode respectively, the 3rd switch conduction when this DC input voitage surpasses this threshold value.
7. input excess voltage protection as claimed in claim 6; it is characterized in that; the 3rd switch comprises a N channel fet, and the drain electrode end of this N channel fet, source terminal and gate terminal couple first end, second end and the control end of the 3rd switch respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205904283U CN201860257U (en) | 2010-11-02 | 2010-11-02 | Input overvoltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205904283U CN201860257U (en) | 2010-11-02 | 2010-11-02 | Input overvoltage protection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN201860257U true CN201860257U (en) | 2011-06-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010205904283U Expired - Fee Related CN201860257U (en) | 2010-11-02 | 2010-11-02 | Input overvoltage protection circuit |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102843019A (en) * | 2012-08-23 | 2012-12-26 | 广州金升阳科技有限公司 | Filter circuit |
| CN103296913A (en) * | 2012-03-02 | 2013-09-11 | 台达电子企业管理（上海）有限公司 | Inverter and active power filter system |
| CN103872888A (en) * | 2012-12-18 | 2014-06-18 | 昆达电脑科技(昆山)有限公司 | Soft switching device |
| CN107453629A (en) * | 2016-04-29 | 2017-12-08 | 英飞凌科技奥地利有限公司 | Voltage multiplie for power converter |
-
2010
- 2010-11-02 CN CN2010205904283U patent/CN201860257U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103296913A (en) * | 2012-03-02 | 2013-09-11 | 台达电子企业管理（上海）有限公司 | Inverter and active power filter system |
| CN103296913B (en) * | 2012-03-02 | 2016-06-22 | 台达电子企业管理（上海）有限公司 | Inverter and active power filter system |
| CN102843019A (en) * | 2012-08-23 | 2012-12-26 | 广州金升阳科技有限公司 | Filter circuit |
| CN102843019B (en) * | 2012-08-23 | 2016-01-20 | 广州金升阳科技有限公司 | A kind of filter circuit |
| CN103872888A (en) * | 2012-12-18 | 2014-06-18 | 昆达电脑科技(昆山)有限公司 | Soft switching device |
| CN107453629A (en) * | 2016-04-29 | 2017-12-08 | 英飞凌科技奥地利有限公司 | Voltage multiplie for power converter |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110608 Termination date: 20131102 |