CN202616771U - Power supply wrong connection protection high-voltage circuit - Google Patents
Power supply wrong connection protection high-voltage circuit Download PDFInfo
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- CN202616771U CN202616771U CN 201220134650 CN201220134650U CN202616771U CN 202616771 U CN202616771 U CN 202616771U CN 201220134650 CN201220134650 CN 201220134650 CN 201220134650 U CN201220134650 U CN 201220134650U CN 202616771 U CN202616771 U CN 202616771U
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Abstract
The utility model relates to a power supply wrong connection protection high-voltage circuit, which is simple in construction and wide in application range. The power supply wrong connection protection high-voltage circuit comprises a current-limiting resistor R1, diodes and a NMOS field effect transistor, wherein the diodes comprise a first diode D1, a second diode D2,...... and a n-th diode Dn; one end of the current-limiting resistor R1 is connected with a power supply, the other end of the current-limiting resistor R1 is connected with a grid electrode of the NMOS field effect transistor, a drain electrode of the NMOS field effect transistor is grounded, a source electrode of the NMOS field effect transistor is shorted with a substrate and then connected with a device to be protected, the first diode D1, the second diode D2,...... and the n-th diode Dn are sequentially connected in series along the same polarity direction, an anode of the first diode D1 is connected with a connection end of the current-limiting resistor R1 and the grid electrode of the NMOS field effect transistor, a cathode of the n-th diode Dn is grounded. The power supply wrong connection protection high-voltage circuit is suitable for power supply wrong connection protection of circuits or electric appliances.
Description
Technical field
The utility model relates to protective circuit, particularly the power supply reverse-connection protection circuit.
Background technology
In the use of power management product work, the situation of power supply reversal connection sometimes can take place, in case reversal connection, the parasitic diode of chip produces very large reverse current with conducting, causes chip to be burnt.Traditional power supply reverse-connection protection circuit such as Fig. 1 show: this circuit is to connect diode at protected electrical equipment front end, utilizes diode pair current reversal blocking characteristics, and reversal connection plays the protection use to power supply.Because the problem of pressure drop of diode makes the application of circuit under low voltage condition of Fig. 1 receive significant limitation.Fig. 2 is the disclosed power supply reverse-connection protection circuit of CN1355607A utility application; It is with protection with the drain electrode of PMOS FET 14 and substrate be connected by the negative electrode of the substrate of the PMOS FET 10 in the protective circuit and parasitic diode 12; In case error-polarity connection of power supply; The protection FET will form and open circuit, and prevents that electric current from burning element in the circuit.The weak point of this circuit is that object of protection is extensive inadequately, and range of application is restricted, and at first this circuit is only applicable in the integrated circuit; If even next supply voltage in integrated circuit is higher, the FET N2 in this circuit is breakdown because of tolerating high pressure, then circuit will burn.
Summary of the invention
The utility model will solve existing power supply reverse-connection protection circuit application problem widely inadequately, and a kind of power supply reverse connecting protection high-tension circuit of the utility model is provided for this reason, and this circuit application object is wide.
For addressing the above problem; Its special character of technical scheme that the utility model adopts is made up of current-limiting resistance R1, diode and NMOS FET; Said diode has the 1st diode D1, the 2nd diode D2 ... With n diode Dn; Current-limiting resistance R1 one termination power, the grid of another termination of current-limiting resistance R1 NMOS FET, the grounded drain of NMOS FET; Connect protected device behind the source electrode of NMOS FET and the substrate short circuit; Said the 1st diode D1, the 2nd diode D2 ... With the identically series connection in succession of n diode Dn polar orientation, the anode of the 1st diode D1 is connected the minus earth of n diode Dn with the end that connects of said current-limiting resistance R1 and NMOS fet gate.
Said protected device can be protected circuit, also can be protected electrical appliance.
The number n of said diode in series in succession depends on the grid source puncture voltage of NMOS FET.
For different integrated circuit technologies or discrete device, the grid source puncture voltage of high-pressure MOS FET is different, in the at present common high-pressure process; NMOS FET grid source puncture voltage VGS_BV=5V, its cut-in voltage Vth is about 0.7V, and the withstand voltage 24V that has is leaked in the source; 40V, plurality of specifications such as 60V and 600V are example with diode forward conducting voltage VF=0.7V; The utility model operation principle is described: normal condition current-limiting resistance R1 connects the positive source high pressure; Choose n=6 according to VGS_BV=5V this moment, through after the resistance R 1 again through 6 diodes, so NMOS FET gate source voltage VGS to equal 6 diode forward pressure drops basically be 4.2V; This voltage is lower than the grid source puncture voltage VGS_BV of NMOS pipe, so can not cause gate breakdown dangerous to the NMOS FET.Because NMOS FET grounded drain, and VGS＞Vt, the NMOS FET is in anti-type state; But VD=0; The NMOS FET is in linear zone, so the NMOS FET is equivalent to the switch of a conducting, and its source voltage is approximately zero; Because the FET source electrode connects by protective circuit or electrical appliance, so circuit or electrical appliance can operate as normal.
In the time of the supply voltage reversal connection, current-limiting resistance R1 connecting to neutral potential end, the drain electrode of NMOS FET connects high voltage; Obstructed because of diode reverse, voltage also is 0 between current-limiting resistance and the diode, and this moment, NMODS fet gate voltage was 0; Therefore the NMOS FET turn-offs; NMOS FET source electrode is a zero level, and circuit or electrical appliance voltage all are 0 like this, have effectively protected circuit or electrical appliance.
FET in the utility model also can replace with triode, when replacing with triode, and the source electrode of FET, grid, drain electrode is emitter, base stage and the collector electrode of corresponding triode respectively.
It is a kind of power supply reverse connecting protection high-tension circuit of the utility model; Be made up of current-limiting resistance R1, diode and triode, said diode has the 1st diode D1, the 2nd diode D2 ... With n diode Dn, current-limiting resistance R1 one termination power; The base stage of another termination triode of current-limiting resistance R1; The grounded collector of triode, the emitter of triode connects protected device, said the 1st diode D1, the 2nd diode D2 ... With the identically series connection in succession of n diode Dn polar orientation; The anode of the 1st diode D1 is connected the minus earth of n diode Dn with the end that connects of said current-limiting resistance R1 and transistor base.
The utility model and Fig. 1 circuit ratio have the characteristics high with functional reliability that pressure drop is little, caloric value is few.The utility model and Fig. 2 circuit ratio have high pressure resistant and simple and practical characteristics.
Description of drawings
Fig. 1 is known a kind of power supply reverse-connection protection circuit figure;
Fig. 2 is known another kind of power supply reverse-connection protection circuit figure;
Fig. 3 is a kind of power supply reverse-connection protection circuit figure of the utility model.
Embodiment
Power supply reverse connecting protection high-tension circuit; By current-limiting resistance R1, NMOS FET and the 1st diode D1, the 2nd diode D2, the 3rd diode D3 ... Form current-limiting resistance R1 one termination power VDD, the grid G of another termination of current-limiting resistance R1 NMOS FET with n diode Dn; The drain D ground connection of NMOS FET; Meet protected device PROTECTED behind the source S of NMOS FET and the substrate short circuit, protected device can be a circuit, also can be electrical appliance; Said the 1st diode D1, the 2nd diode D2, the 3rd diode D3 ... With the identically series connection in succession of n diode Dn polar orientation; The anode of the 1st diode D1 is connected the minus earth of n diode Dn with the end that connects of current-limiting resistance R1 and NMOS fet gate.The numerical value of n is that the number of diode depends on the grid source puncture voltage VGS_BV of selected NMOS FET and the forward voltage drop VF of diode; Selection principle is n * VF≤VGS_BV; But the value of n*VF will be as far as possible near VGS_BV under the situation that guarantees this safety condition, and promptly n obtains big as far as possible.Because for FET, its gate source voltage is high more, and then its conducting resistance is more little.Like VGS_BV=5V; VF=0.7, then optional n=6 or 7 considers that diode VF and grid source puncture voltage VGS_BV drift can occur with technology; N * VF=4.9V when n selects 7; Too, when drift appears in the VF parameter, float to 0.8V like portioned product VF and the situation that FET gate source voltage VGS surpasses puncture voltage then might occur near grid source puncture voltage VGS_BV=5V.So select n=6.To part of devices or technology, n diode can replace with Zener diode or triode.
Claims (3)
1. power supply reverse connecting protection high-tension circuit; It is characterized in that forming by current-limiting resistance R1, diode and NMOS FET; Said diode has the 1st diode D1, the 2nd diode D2 ... With n diode Dn; Current-limiting resistance R1 one termination power, the grid of another termination of current-limiting resistance R1 NMOS FET, the grounded drain of NMOS FET; Connect protected device behind the source electrode of NMOS FET and the substrate short circuit; Said the 1st diode D1, the 2nd diode D2 ... With the identically series connection in succession of n diode Dn polar orientation, the anode of the 1st diode D1 is connected the minus earth of n diode Dn with the end that connects of said current-limiting resistance R1 and NMOS fet gate.
2. circuit as claimed in claim 1 is characterized in that said protected device is protected circuit or protected electrical appliance.
3. power supply reverse connecting protection high-tension circuit; It is characterized in that being made up of current-limiting resistance R1, diode and triode, said diode has the 1st diode D1, the 2nd diode D2 ... With n diode Dn, current-limiting resistance R1 one termination power; The base stage of another termination triode of current-limiting resistance R1; The grounded collector of triode, the emitter of triode connects protected device, said the 1st diode D1, the 2nd diode D2 ... With the identically series connection in succession of n diode Dn polar orientation; The anode of the 1st diode D1 is connected the minus earth of n diode Dn with the end that connects of said current-limiting resistance R1 and transistor base.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220134650 CN202616771U (en) | 2012-04-01 | 2012-04-01 | Power supply wrong connection protection high-voltage circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220134650 CN202616771U (en) | 2012-04-01 | 2012-04-01 | Power supply wrong connection protection high-voltage circuit |
Publications (1)
| Publication Number | Publication Date |
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| CN202616771U true CN202616771U (en) | 2012-12-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220134650 Expired - Lifetime CN202616771U (en) | 2012-04-01 | 2012-04-01 | Power supply wrong connection protection high-voltage circuit |
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| CN (1) | CN202616771U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102638034A (en) * | 2012-04-01 | 2012-08-15 | 杭州科岛微电子有限公司 | Reverse connection protection high pressure circuit of power supply |
| CN104426145A (en) * | 2013-09-09 | 2015-03-18 | 海洋王（东莞）照明科技有限公司 | Inverse connection prevention circuit and lamp |
| CN109217242A (en) * | 2018-11-08 | 2019-01-15 | 上海艾为电子技术股份有限公司 | A kind of power-switching circuit with counnter attack connection function, integrated circuit |
| CN111463744A (en) * | 2020-04-10 | 2020-07-28 | 中国科学院西安光学精密机械研究所 | Self-recovery under-voltage protection circuit with hysteresis effect |
-
2012
- 2012-04-01 CN CN 201220134650 patent/CN202616771U/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102638034A (en) * | 2012-04-01 | 2012-08-15 | 杭州科岛微电子有限公司 | Reverse connection protection high pressure circuit of power supply |
| CN104426145A (en) * | 2013-09-09 | 2015-03-18 | 海洋王（东莞）照明科技有限公司 | Inverse connection prevention circuit and lamp |
| CN104426145B (en) * | 2013-09-09 | 2018-09-11 | 海洋王（东莞）照明科技有限公司 | Prevent reversed circuit and lamps and lanterns |
| CN109217242A (en) * | 2018-11-08 | 2019-01-15 | 上海艾为电子技术股份有限公司 | A kind of power-switching circuit with counnter attack connection function, integrated circuit |
| CN109217242B (en) * | 2018-11-08 | 2024-01-30 | 上海艾为电子技术股份有限公司 | Power supply conversion circuit with reverse connection preventing function and integrated circuit |
| CN111463744A (en) * | 2020-04-10 | 2020-07-28 | 中国科学院西安光学精密机械研究所 | Self-recovery under-voltage protection circuit with hysteresis effect |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20121219 |
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| CX01 | Expiry of patent term |