CN102801130A - Protection circuit - Google Patents
Protection circuit Download PDFInfo
- Publication number
- CN102801130A CN102801130A CN2011101336209A CN201110133620A CN102801130A CN 102801130 A CN102801130 A CN 102801130A CN 2011101336209 A CN2011101336209 A CN 2011101336209A CN 201110133620 A CN201110133620 A CN 201110133620A CN 102801130 A CN102801130 A CN 102801130A
- Authority
- CN
- China
- Prior art keywords
- comparator
- voltage source
- electronic switch
- voltage
- output voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Landscapes
- Emergency Protection Circuit Devices (AREA)
- Electronic Switches (AREA)
Abstract
The invention provides a protection circuit. The protection circuit comprises a comparator and an electronic switch, wherein the non-inverting input end of the comparator is connected with a first voltage source, the inverting input end thereof is connected with an output voltage source, and the output end thereof is connected with the first end of the electronic switch by a first resistor; the second end of the electronic switch is connected with external equipment, and the third end thereof is connected with the output voltage source; when the voltage received by the non-inverting input end of the comparator is not lower than that received by the inverting input end, the comparator outputs a high level signal, so that the electronic switch is turned on, and then the voltage of the output voltage source is output to the external equipment; and when the voltage received by the non-inverting input end of the comparator is higher than that received by the inverting input end, the comparator outputs a low level signal, so that the electronic switch is cut off, and then the voltage is not output to the external equipment. The protection circuit can cut off connection between the output voltage source and the external equipment when the output voltage source is abnormal.
Description
Technical field
The present invention relates to a kind of protective circuit.
Background technology
The general USB overvoltage protection mode that is designed on the market is to design with assemblies such as resistance/fuses, but this kind mode must the calculated resistance value be adjusted its voltage so that meet the input voltage of receiving terminal, so very inconvenience.
Summary of the invention
In view of above content, be necessary to provide a kind of protective circuit comparatively easily.
A kind of protective circuit; Comprise a comparator and an electronic switch; The in-phase input end of this comparator links to each other with one first voltage source, and inverting input links to each other with an output voltage source, and output links to each other with first end of electronic switch through one first resistance; Second end of this electronic switch is used for linking to each other with an external equipment, and the 3rd end links to each other with this output voltage source; Wherein, This output voltage source is used to external equipment operating voltage is provided; When the voltage that in-phase input end received of this comparator is not less than the voltage that inverting input receives; This comparator is exported a high level signal, so that electronic switch conducting and then export the voltage of output voltage source to external equipment, when the voltage that in-phase input end received of this comparator during greater than voltage that inverting input received; This comparator is exported a low level signal so that electronic switch by so that not output voltage to external equipment.
Above-mentioned protective circuit judges through the magnitude of voltage of its in-phase input end of comparator comparison and inverting input whether output voltage source occurs unusually; If output voltage source occurs then cutting off being connected between output voltage source and the external equipment through electronic switch unusually, be damaged to avoid external equipment.
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
| Comparator | U1 |
| Diode | D1 |
| Fuse | U2 |
| First voltage source | VCC1 |
| Second voltage source | VCC2 |
| Triode | Q1 |
| Resistance | R1、R2 |
| |
1 |
| |
2 |
| Output voltage source | VCC3 |
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, the preferred embodiments of protective circuit of the present invention comprises a comparator U1, a diode D1, a fuse U2, one first voltage source V CC1, one second voltage source V CC2, a triode Q1 and resistance R 1, R2.
The inverting input of this comparator U1 links to each other with output voltage source VCC3 through fuse U2, and in-phase input end links to each other with the first voltage source V CC1, and output links to each other with the base stage of triode Q1 through resistance R 1.The collector electrode of this triode Q1 links to each other with the inverting input of comparator U1, and emitter is used for output voltage to external equipment 1 (like a USB electronic equipment).
The emitter of this triode Q1 also links to each other with the negative electrode of diode D1, and the anode of this diode D1 links to each other with a processor 2, also links to each other with the second voltage source V CC2 through resistance R 2.The anode of this diode D1 is used for when output voltage source VCC3 overvoltage, exporting an overvoltage signal to this processor 2.
To the operation principle of protective circuit of the present invention be described below:
This first voltage source V CC1 is a reference voltage, and it is identical with the normal working voltage value of external equipment 1 that its voltage is set to, and the voltage of this second voltage source V CC2 is less than the magnitude of voltage of output voltage source VCC3.When the voltage of output voltage source VCC3 no abnormal; Be that its voltage is when satisfying requiring of external equipment 1; The in-phase input end of this comparator U1 and the magnitude of voltage of inverting input equate; This comparator U1 output this moment high level signal promptly makes triode Q1 conducting, and then makes output voltage source VCC3 export voltage to external equipment 1.In addition; Because the magnitude of voltage (i.e. the magnitude of voltage of the second voltage source V CC2) of the anode of this diode D1 is less than the magnitude of voltage (being the magnitude of voltage of output voltage source VCC3) of its negative electrode; Therefore this diode D1 ends; This processor 2 promptly receives high level signal, expression this output voltage source VCC3 this moment operate as normal.
When the voltage of output voltage source VCC3 is higher than the operating voltage of external equipment 1; The magnitude of voltage of the in-phase input end of this comparator U1 is less than the magnitude of voltage of its inverting input; This moment this comparator U1 output output low level signal; Promptly make triode Q1 end, and then make output voltage source VCC3 not export voltage to external equipment 1.In addition; The magnitude of voltage (i.e. the magnitude of voltage of the second voltage source V CC2) of the anode of this diode D1 will be greater than the magnitude of voltage (being the magnitude of voltage of the output of comparator U1) of its negative electrode at this moment; Therefore this diode D1 conducting; At this moment, this processor 2 will receive low level signal, and expression this output voltage source VCC3 this moment occurs unusual.In addition, this fuse U2 will be fused, with directly cutting off being connected between output voltage source VCC3 and the protective circuit.
Can find out from operation principle; This triode Q1 plays the effect of electronic switch in circuit, therefore, and in other execution mode; This triode Q1 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 FET to replace this triode Q1, low level control signal promptly makes this FET end, low level control signal promptly makes this FET conducting, its operation principle is identical with triode.Other electronic switch similarly repeats 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 output of comparator U1 through resistance R 1, and second end links to each other with external equipment 1, and the 3rd end links to each other with fuse U2.
Above-mentioned protective circuit judges through the magnitude of voltage that comparator U1 compares its in-phase input end and inverting input whether output voltage source VCC3 occurs unusually; If output voltage source VCC3 occurs then cutting off being connected between output voltage source VCC3 and the external equipment 1 through triode Q1 unusually, be damaged to avoid external equipment 1.
Claims (4)
1. protective circuit; Comprise a comparator and an electronic switch; The in-phase input end of this comparator links to each other with one first voltage source, and inverting input links to each other with an output voltage source, and output links to each other with first end of electronic switch through one first resistance; Second end of this electronic switch is used for linking to each other with an external equipment, and the 3rd end links to each other with this output voltage source; Wherein, This output voltage source is used to external equipment operating voltage is provided; When the voltage that in-phase input end received of this comparator is not less than the voltage that inverting input receives; This comparator is exported a high level signal, so that electronic switch conducting and then export the voltage of output voltage source to external equipment, when the voltage that in-phase input end received of this comparator during greater than voltage that inverting input received; This comparator is exported a low level signal so that electronic switch by so that not output voltage to external equipment.
2. protective circuit as claimed in claim 1; It is characterized in that: said protective circuit also comprises a diode; The anode of this diode links to each other with a processor; Also link to each other with one second voltage source through one second resistance, negative electrode links to each other with the output of comparator, and this diode is used for when electronic switch ends, sending an abnormal signal to this processor.
3. protective circuit as claimed in claim 1 is characterized in that: this electronic switch is a triode, and its base stage, emitter and collector electrode are respectively first end, second end and the 3rd end of electronic switch.
4. protective circuit as claimed in claim 1 is characterized in that: also be connected a fuse between the inverting input of this output voltage source and comparator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011101336209A CN102801130A (en) | 2011-05-23 | 2011-05-23 | Protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011101336209A CN102801130A (en) | 2011-05-23 | 2011-05-23 | Protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102801130A true CN102801130A (en) | 2012-11-28 |
Family
ID=47200149
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011101336209A Pending CN102801130A (en) | 2011-05-23 | 2011-05-23 | Protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102801130A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103595396A (en) * | 2013-11-04 | 2014-02-19 | 矽恩微电子(厦门)有限公司 | IC parameter correcting circuit |
| CN107219882A (en) * | 2017-07-12 | 2017-09-29 | 山东建筑大学 | A kind of positive-negative power with short-circuit protection function |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101043134A (en) * | 2006-03-20 | 2007-09-26 | 佛山市顺德区顺达电脑厂有限公司 | Over-voltage protection circuit |
| CN101119021A (en) * | 2006-05-10 | 2008-02-06 | 三星电子株式会社 | Over voltage protection circuit and method thereof |
| CN101656414A (en) * | 2008-08-20 | 2010-02-24 | 鸿富锦精密工业（深圳）有限公司 | Power protection device |
-
2011
- 2011-05-23 CN CN2011101336209A patent/CN102801130A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101043134A (en) * | 2006-03-20 | 2007-09-26 | 佛山市顺德区顺达电脑厂有限公司 | Over-voltage protection circuit |
| CN101119021A (en) * | 2006-05-10 | 2008-02-06 | 三星电子株式会社 | Over voltage protection circuit and method thereof |
| CN101656414A (en) * | 2008-08-20 | 2010-02-24 | 鸿富锦精密工业（深圳）有限公司 | Power protection device |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103595396A (en) * | 2013-11-04 | 2014-02-19 | 矽恩微电子(厦门)有限公司 | IC parameter correcting circuit |
| CN103595396B (en) * | 2013-11-04 | 2019-03-15 | 矽恩微电子(厦门)有限公司 | A kind of IC parameter correction circuit |
| CN107219882A (en) * | 2017-07-12 | 2017-09-29 | 山东建筑大学 | A kind of positive-negative power with short-circuit protection function |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102004183A (en) | Voltage detection circuit | |
| CN202939292U (en) | Direct-current power supply monitoring circuit | |
| CN104104067A (en) | Short circuit protection circuit | |
| CN105226604A (en) | A kind of under-voltage/over-voltage protection circuit and Set Top Box | |
| CN103324265A (en) | Power protection circuit | |
| CN105633905A (en) | Overvoltage and under-voltage protection circuit | |
| CN102361319B (en) | IGBT (Insulated Gate Bipolar Translator) short circuit protection detection circuit based on driving chip | |
| CN201629569U (en) | Over-voltage protection circuit of USB interface | |
| CN203734283U (en) | Power supply protection circuit and power supply device | |
| CN104113039A (en) | Over-voltage protection circuit | |
| CN104753034A (en) | Electronic device and charging protection circuit thereof | |
| CN102801130A (en) | Protection circuit | |
| US8767365B2 (en) | Protection circuit | |
| CN104426119B (en) | A kind of power output protection circuit | |
| CN202906437U (en) | Input undervoltage protection circuit | |
| CN103166171A (en) | Universal serial bus (USB) overcurrent protection circuit | |
| CN105470913A (en) | Overvoltage protection circuit | |
| CN104656724A (en) | Electronic device | |
| CN104423519A (en) | Mainboard power supply system | |
| CN204719122U (en) | A kind of voltage detecting warning circuit | |
| CN208971122U (en) | Overvoltage crowbar and power bus slave circuit | |
| CN104252216A (en) | Anti-creeping USB (universal serial bus) power supply circuit | |
| CN103475205A (en) | Protective circuit | |
| CN103902009A (en) | Discharge circuit | |
| CN103383579A (en) | Reference voltage source |
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: 20121128 |