CN102751709A - Protection circuit - Google Patents
Protection circuit Download PDFInfo
- Publication number
- CN102751709A CN102751709A CN2011100991195A CN201110099119A CN102751709A CN 102751709 A CN102751709 A CN 102751709A CN 2011100991195 A CN2011100991195 A CN 2011100991195A CN 201110099119 A CN201110099119 A CN 201110099119A CN 102751709 A CN102751709 A CN 102751709A
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- electronic switch
- voltage source
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- pmos fet
- electronic equipment
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- Protection Of Static Devices (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention discloses a protection circuit which is connected between an output power source and a piece of electronic equipment. The protection circuit comprises a voltage source, an RC (Resistor Capacitor) parallel loop, a phase inverter, a first electronic switch and a second electronic switch. The voltage source is connected with the RC parallel loop through a first resistor and is connected with the input end of the phase inverter. The output end of the phase inverter is connected with the first end of the first electronic switch, the second end of the electronic switch is grounded, and the third end of the first electronic switch is connected with the voltage source through a second resistor and is directly connected with the first end of the second electronic switch. The second end of the second electronic switch is connected with the electronic equipment and the third end of the second electronic switch is connected with the output power source. The protection circuit can protect the electronic equipment against the damages caused by surge current appearing at the time that the power source is started.
Description
Technical field
The present invention relates to a kind of protective circuit.
Background technology
In some electronic device circuitry, usually all surge current can be arranged during power-on, and this electric current is bigger, if this surge current is not taken measures, it causes damage to electronic equipment probably.
Summary of the invention
In view of above content, be necessary to provide a kind of protective circuit,, out-put supply receives the damage of surge current when opening to avoid electronic equipment.
A kind of protective circuit is connected between an out-put supply and the electronic equipment, and this protective circuit comprises a voltage source, a RC shunt circuit, an inverter, one first electronic switch and one second electronic switch; This voltage source links to each other with the RC shunt circuit through one first resistance; Also link to each other with the input of this inverter, the output of this inverter links to each other with first end of first electronic switch, the second end ground connection of this first electronic switch; The 3rd end links to each other with voltage source through one second resistance; Also directly link to each other with first end of second electronic switch, second end of this second electronic switch links to each other with this electronic equipment, and the 3rd end links to each other with this out-put supply.
Above-mentioned protective circuit when out-put supply is unlocked, not immediately output voltage to electronic equipment.As time goes on, when the electric capacity in the RC shunt circuit was recharged to certain voltage value, just output voltage was to electronic equipment for this out-put supply, and the surge current that is produced in the time of so can avoiding out-put supply to open is to damage that electronic equipment caused.
Description of drawings
Fig. 1 is the circuit diagram of the preferred embodiments of protective circuit of the present invention.
The main element symbol description
| Out-put supply | 1 |
| |
2 |
| Voltage source | VCC |
| Resistance | R1-R3 |
| Electric capacity | C1 |
| Inverter | U1A |
| The PMOS FET | Q1、Q2 |
Following embodiment will combine above-mentioned accompanying drawing to further specify the present invention.
Embodiment
Below in conjunction with accompanying drawing and preferred embodiments the present invention is described in further detail:
See also Fig. 1, protective circuit of the present invention is connected between an out-put supply 1 and the electronic equipment 2, is used to avoid electronic equipment 2 when start, to receive the damage of surge current.The preferred embodiments of this protective circuit comprises a voltage source V CC, resistance R 1, R2, R3, a capacitor C 1, an inverter U1A, PMOS FET Q1 and Q2.
Through resistance R 1 and R2 ground connection, the node between this resistance R 1 and the R2 links to each other with the input of inverter U1A this voltage source V CC successively, also directly through capacitor C 1 ground connection.The output of this inverter U1A links to each other with the grid of PMOS FET Q1, the source ground of this PMOS FET Q1, and drain electrode links to each other with voltage source V CC through resistance R 3.The grid of this PMOS FET Q2 links to each other with the drain electrode of PMOS FET Q1, and the drain electrode of this PMOS FET Q2 links to each other with out-put supply 1, and source electrode links to each other with electronic equipment 2.
To the operation principle of protective circuit of the present invention be described below:
This resistance R 2 and capacitor C 1 are formed the RC shunt circuit.When out-put supply 1 was unlocked, this voltage source V CC also was unlocked simultaneously, and it promptly begins capacitor C 1 is charged.The moment that this out-put supply 1 is opened, the electric weight of this capacitor C 1 is zero, and promptly the input of this inverter U1A receives low level signal.According to the operation principle of inverter, its output will be exported high level signal, promptly make PMOS FET Q1 end, and make the grid of PMOS FET Q2 receive the high level signal from voltage source V CC then, and promptly PMOS FET Q2 also ends.So will make out-put supply 1 can't export to electronic equipment 2.
Continuity along with the time; This voltage source V CC is continuously capacitor C 1 charging; When the voltage of capacitor C 1 reached the conducting voltage of PMOS FET Q1, the anti-phase of process inverter U1A can make and PMOS FET Q1 conducting make the grid of PMOS FET Q2 receive a low level then; Be also conducting of PMOS FET Q2, so will make voltage transmission to the electronic equipment 2 that out-put supply 1 is exported.
Can find out from operation principle; This PMOS FET Q1 and Q2 play the effect of electronic switch in circuit; Therefore; In other execution mode, this PMOS FET Q1 and Q2 also can adopt the transistor of other type or FET to replace, even other electronic building brick with electronic switch function all can.Such as; When utilizing a positive-negative-positive triode to replace this PMOS FET Q1; The control signal of high level promptly makes this positive-negative-positive triode end, low level control signal promptly makes this positive-negative-positive triode conducting, and its operation principle is identical with the PMOS FET.Triode and other electronic switch similarly repeat no more at this.This electronic switch comprises one first end, one second end and one the 3rd end, and this first end links to each other with the input of inverter U1A, the second end ground connection, and the 3rd end links to each other with voltage source V CC through resistance R 3.This PMOS FET Q2 is identical with PMOS FET Q1.
Can know that according to top description when out-put supply 1 was unlocked, it is output voltage to electronic equipment 2 immediately not.As time goes on, when capacitor C 1 was recharged to certain voltage value, this out-put supply 1 is output voltage to electronic equipment 2.The damage that the surge current that is produced in the time of so can avoiding out-put supply 1 to open is caused electronic equipment 2.
Claims (3)
1. a protective circuit is connected between an out-put supply and the electronic equipment, and this protective circuit comprises a voltage source, a RC shunt circuit, an inverter, one first electronic switch and one second electronic switch; This voltage source links to each other with the RC shunt circuit through one first resistance; Also link to each other with the input of this inverter, the output of this inverter links to each other with first end of first electronic switch, the second end ground connection of this first electronic switch; The 3rd end links to each other with voltage source through one second resistance; Also directly link to each other with first end of second electronic switch, second end of this second electronic switch links to each other with this electronic equipment, and the 3rd end links to each other with this out-put supply.
2. protective circuit as claimed in claim 1 is characterized in that: this first electronic switch is a PMOS FET, and its first end, second end and the 3rd end are respectively grid, source electrode and the drain electrode of PMOS FET.
3. protective circuit as claimed in claim 1 is characterized in that: this second electronic switch is a PMOS FET, and its first end, second end and the 3rd end are respectively grid, source electrode and the drain electrode of PMOS FET.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100991195A CN102751709A (en) | 2011-04-20 | 2011-04-20 | Protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100991195A CN102751709A (en) | 2011-04-20 | 2011-04-20 | Protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102751709A true CN102751709A (en) | 2012-10-24 |
Family
ID=47031683
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011100991195A Pending CN102751709A (en) | 2011-04-20 | 2011-04-20 | Protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102751709A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105159427A (en) * | 2015-08-03 | 2015-12-16 | 浪潮(北京)电子信息产业有限公司 | Level signal control method and system and combined logic circuits |
| CN108736458A (en) * | 2018-07-20 | 2018-11-02 | 浙江机电职业技术学院 | DA powers on anti-impact circuit in multichannel microcontroller |
| CN109917162A (en) * | 2019-03-25 | 2019-06-21 | 昆山龙腾光电有限公司 | A kind of power protecting circuit and test device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5910690A (en) * | 1997-02-11 | 1999-06-08 | Cabletron Systems, Inc. | Hotswappable chassis and electronic circuit cards |
| US6411482B1 (en) * | 2000-02-15 | 2002-06-25 | Eaton Corporation | Surge protector comprising means for detecting and permanently recording an overvoltage event and panelboard employing the same |
| CN1734761A (en) * | 2004-08-04 | 2006-02-15 | 台湾积体电路制造股份有限公司 | Fuse circuit and electric fuse circuit with electrostatic discharge protection |
| CN101882864A (en) * | 2010-06-25 | 2010-11-10 | 杭州矽力杰半导体技术有限公司 | Electrifying startup circuit and electrifying startup method thereof |
-
2011
- 2011-04-20 CN CN2011100991195A patent/CN102751709A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5910690A (en) * | 1997-02-11 | 1999-06-08 | Cabletron Systems, Inc. | Hotswappable chassis and electronic circuit cards |
| US6411482B1 (en) * | 2000-02-15 | 2002-06-25 | Eaton Corporation | Surge protector comprising means for detecting and permanently recording an overvoltage event and panelboard employing the same |
| CN1734761A (en) * | 2004-08-04 | 2006-02-15 | 台湾积体电路制造股份有限公司 | Fuse circuit and electric fuse circuit with electrostatic discharge protection |
| CN101882864A (en) * | 2010-06-25 | 2010-11-10 | 杭州矽力杰半导体技术有限公司 | Electrifying startup circuit and electrifying startup method thereof |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105159427A (en) * | 2015-08-03 | 2015-12-16 | 浪潮(北京)电子信息产业有限公司 | Level signal control method and system and combined logic circuits |
| CN105159427B (en) * | 2015-08-03 | 2019-03-12 | 浪潮(北京)电子信息产业有限公司 | A level signal control method, system and combinational logic circuit |
| CN108736458A (en) * | 2018-07-20 | 2018-11-02 | 浙江机电职业技术学院 | DA powers on anti-impact circuit in multichannel microcontroller |
| CN108736458B (en) * | 2018-07-20 | 2023-10-17 | 浙江机电职业技术学院 | Multi-channel microcontroller on-chip DA power-on anti-shock circuit |
| CN109917162A (en) * | 2019-03-25 | 2019-06-21 | 昆山龙腾光电有限公司 | A kind of power protecting circuit and test device |
| CN109917162B (en) * | 2019-03-25 | 2021-08-06 | 昆山龙腾光电股份有限公司 | Power supply protection circuit and testing device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20121024 |