CN203039343U - Intrinsic safe over-current protection circuit - Google Patents
Intrinsic safe over-current protection circuit Download PDFInfo
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- CN203039343U CN203039343U CN 201220745539 CN201220745539U CN203039343U CN 203039343 U CN203039343 U CN 203039343U CN 201220745539 CN201220745539 CN 201220745539 CN 201220745539 U CN201220745539 U CN 201220745539U CN 203039343 U CN203039343 U CN 203039343U
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Abstract
The utility model discloses an intrinsic safe over-current protection circuit. The intrinsic safe over-current protection circuit comprises a current sampling unit, an amplification comparison circuit and a switch circuit. According to the intrinsic safe over-current protection circuit of the utility model, the current sampling unit is used to detect a load current; the amplification comparison circuit is used to convert and amplify the load current into a voltage signal; the voltage signal is compared with a preset reference voltage; the switch circuit is used to control opening and closing of the circuit. When the load current is too large, connection between the load and a power supply can be timely disconnected and device safety is guaranteed.
Description
Technical field
The utility model relates to a kind of intrinsic safety current foldback circuit, relates in particular to the intrinsic safety current foldback circuit in the mine intrinsic safety equipment.
Background technology
At present, the intrinsic safety equipment that uses in the down-hole, mine generally is to adopt the mode of series resistance to reach the intrinsic safety overcurrent protection.When the intrinsic safety device interior is short-circuited, can limiting short-circuit current, i.e. maximum short circuit current by series resistance.Like this, this resistance will consume maximum power dissipation, and the temperature of resistance will be very high, have a strong impact on device security and the mine environment safety of intrinsically safe circuit.
The utility model content
Technical problem to be solved in the utility model is to provide a kind of intrinsic safety current foldback circuit, support equipment safety.
The utility model is achieved through the following technical solutions: a kind of intrinsic safety current foldback circuit, be connected between power supply and the load, and described intrinsic safety current foldback circuit comprises:
Current sampling unit is for detection of the current value of described load;
Amplify comparison circuit, be used for the current value of described load is zoomed into voltage signal, and described voltage signal and preset reference voltage are compared;
Switching circuit is for the break-make of controlling according to the comparative result of described amplification comparison circuit between described power supply and the described load.
As further improvement of the utility model, described current sampling unit is sampling resistor.
As further improvement of the utility model, described intrinsic safety current foldback circuit has input and output, and described input has input anode and input cathode, and described output has output head anode and negative pole of output end; Described intrinsic safety current foldback circuit also comprises the current-limiting resistance that is connected between described input anode and the described output head anode.
As further improvement of the utility model, described switching circuit comprises first resistance, transistor and metal-oxide-semiconductor, described amplification comparison circuit comprises amplifying circuit and comparison circuit, described comparison circuit comprises comparator, second resistance and the 3rd resistance, and described amplifying circuit comprises amplifier, the 4th resistance, the 5th resistance, the 6th resistance and capacitor; One end of described sampling resistor is connected with described negative pole of output end, the other end of described sampling resistor is connected with the drain electrode of described metal-oxide-semiconductor, the source electrode of described metal-oxide-semiconductor is connected with described input cathode, one end of described first resistance is connected with described input anode, the other end of described first resistance all is connected with described transistorized collector electrode with the grid of described metal-oxide-semiconductor, described transistorized emitter and the equal ground connection of described input cathode, described the 4th resistance is connected between the first input end of an end of described sampling resistor and described amplifier, described the 5th resistance is connected between second input of the other end of described sampling resistor and described amplifier, and described capacitor is connected between second input of the first input end of described amplifier and described amplifier, described the 6th resistance is connected between the output of second input of described amplifier and described amplifier, described the 3rd resistance is connected between the first input end of the output of described amplifier and described comparator, described second resistance is connected between second input of described preset reference voltage and described comparator, and the output of described comparator is connected with described transistorized base stage.
As further improvement of the utility model, described transistor is NPN transistor, and described metal-oxide-semiconductor is the N-channel MOS pipe.
As further improvement of the utility model, described power supply is mining power supply, and described load is pit gear.
The beneficial effects of the utility model are: intrinsic safety current foldback circuit of the present utility model can detect the size of load current by current sampling unit; by amplifying comparison circuit the load current conversion is zoomed into voltage signal; and itself and preset reference voltage compared; opening and closing by the switching circuit control circuit; thereby can be under the excessive situation of load current; in time be connected support equipment safety between disconnecting consumers and the power supply.
Above-mentioned explanation only is the general introduction of technical solutions of the utility model, for can clearer understanding technological means of the present utility model, and can be implemented according to the content of specification, and for above-mentioned and other purpose, feature and advantage of the present utility model can be become apparent, below especially exemplified by embodiment, and conjunction with figs., be described in detail as follows.
Description of drawings
Fig. 1 is the structural representation of intrinsic safety current foldback circuit of the present utility model.
Embodiment
The intrinsic safety current foldback circuit 10 of present embodiment is connected between power supply and the load.When load current was higher than certain value, being connected between these intrinsic safety current foldback circuit 10 auto power offs and the load was to carry out overcurrent protection.
The intrinsic safety current foldback circuit of present embodiment comprises:
Current sampling unit is for detection of the current value of load;
Amplify comparison circuit, be used for the current value conversion of load is zoomed into voltage signal, and voltage signal and preset reference voltage are compared;
Switching circuit is used for according to the break-make between the comparative result control power supply that amplifies comparison circuit and the load.
As shown in Figure 1, in the intrinsic safety current foldback circuit 10 of present embodiment, current sampling unit RS is sampling resistor.Intrinsic safety current foldback circuit 10 has input J1 and output J2.Input J1 has input anode 102 and input cathode 104.Output J2 has output head anode 202 and negative pole of output end 204.Intrinsic safety current foldback circuit 10 also comprises the current-limiting resistance RL that is connected between input anode 102 and the output head anode 202.
In the intrinsic safety current foldback circuit 10 of present embodiment, switching circuit 300 comprises first resistance R 1, transistor Q1 and metal-oxide-semiconductor Q2.Amplify comparison circuit and comprise amplifying circuit 500 and comparison circuit 400.Comparison circuit 400 comprises comparator U2, second resistance R 2 and the 3rd resistance R 3.Amplifying circuit 500 comprises amplifier U1, the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6 and capacitor C1.The end 504 of sampling resistor RS is connected with negative pole of output end 204, and the other end 506 of sampling resistor RS is connected with the drain electrode 306 of metal-oxide-semiconductor Q2.The source electrode 308 of metal-oxide-semiconductor Q2 is connected with input cathode 104.One end 314 of first resistance R 1 is connected with input anode 102, and the grid 304 of the other end of first resistance R 1 and metal-oxide-semiconductor Q2 all is connected with the collector electrode 310 of transistor Q1, the emitter 312 of transistor Q1 and input cathode 104 equal ground connection.
The 4th resistance R 4 is connected between the first input end of the end 504 of sampling resistor RS and amplifier U1, and the 5th resistance R 5 is connected between second input of the other end 506 of sampling resistor RS and amplifier U1.And capacitor C1 is connected between second input of the first input end of amplifier U1 and amplifier U1.The 6th resistance R 6 is connected between the output of second input of amplifier U1 and amplifier U1.
The 3rd resistance R 3 is connected between the first input end 406 of the output 402 of amplifier U1 and comparator U2, second resistance R 2 is connected between second input 408 of preset reference voltage Vref and comparator U2, and the output 404 of comparator U2 is connected with the base stage 302 of transistor Q1.
In the intrinsic safety current foldback circuit 10 of present embodiment, transistor Q1 is NPN transistor, and metal-oxide-semiconductor Q2 is the N-channel MOS pipe.
In the intrinsic safety current foldback circuit 10 of present embodiment, power supply is preferably mining power supply, and load is preferably pit gear.
In the course of work of intrinsic safety current foldback circuit 10, the input J1 (not shown) of connecting with the mains, electric current exports the load (not shown) through current-limiting resistance RL at output J2.Metal-oxide-semiconductor Q2 connects the first resistance R 1(pull-up resistor) on draw after, the closed conducting of metal-oxide-semiconductor Q2.During work, the electric current on the current-limiting resistance RL is along with the load current of output J2 rear end increases and increases.Electric current on the sampling resistor RS also increases and increases along with output J2 rear end load current.When electric current was flowed through sampling resistor RS, the electric current on the sampling resistor RS was exaggerated circuit 500 conversions and zooms into voltage signal.This voltage signal is transferred among the comparator U2.At this moment, comparator U2 compares the preset reference voltage Vref of voltage signal and reference voltage end.When voltage signal during less than preset reference voltage Vref, output 404 output low levels of comparator U2.Transistor Q1 ends, and the grid 304 of metal-oxide-semiconductor Q2 connects high level, metal-oxide-semiconductor Q2 conducting, normal operation circuit.When voltage signal during more than or equal to preset reference voltage Vref, the output 404 output high level of comparator U2, transistor Q1 conducting, the grid 304 of metal-oxide-semiconductor Q2 connects low level, and metal-oxide-semiconductor Q2 ends, and circuit disconnects, and namely is connected disconnection between power supply and the load.
Can detect the size of load current by current sampling unit according to intrinsic safety current foldback circuit of the present utility model; by amplifying comparison circuit the load current conversion is zoomed into voltage signal; and itself and preset reference voltage compared; opening and closing by the switching circuit control circuit; thereby can be under the excessive situation of load current; in time be connected support equipment safety between disconnecting consumers and the power supply.
Above embodiment has been described in detail the utility model, and formation is to restriction of the present utility model but these are not.Protection range of the present utility model is not limited with above-mentioned execution mode, as long as the equivalence that those of ordinary skills do according to the utility model institute disclosure is modified or changed, all should include in the protection range of putting down in writing in claims.
Claims (6)
1. an intrinsic safety current foldback circuit is connected between power supply and the load, it is characterized in that, described intrinsic safety current foldback circuit comprises:
Current sampling unit is for detection of the current value of described load;
Amplify comparison circuit, be used for the current value of described load is zoomed into voltage signal, and described voltage signal and preset reference voltage are compared;
Switching circuit is for the break-make of controlling according to the comparative result of described amplification comparison circuit between described power supply and the described load.
2. intrinsic safety current foldback circuit according to claim 1 is characterized in that, described current sampling unit is sampling resistor.
3. intrinsic safety current foldback circuit according to claim 2, it is characterized in that, described intrinsic safety current foldback circuit has input and output, and described input has input anode and input cathode, and described output has output head anode and negative pole of output end; Described intrinsic safety current foldback circuit also comprises the current-limiting resistance that is connected between described input anode and the described output head anode.
4. intrinsic safety current foldback circuit according to claim 3, it is characterized in that, described switching circuit comprises first resistance, transistor and metal-oxide-semiconductor, described amplification comparison circuit comprises amplifying circuit and comparison circuit, described comparison circuit comprises comparator, second resistance and the 3rd resistance, and described amplifying circuit comprises amplifier, the 4th resistance, the 5th resistance, the 6th resistance and capacitor; One end of described sampling resistor is connected with described negative pole of output end, the other end of described sampling resistor is connected with the drain electrode of described metal-oxide-semiconductor, the source electrode of described metal-oxide-semiconductor is connected with described input cathode, one end of described first resistance is connected with described input anode, the other end of described first resistance all is connected with described transistorized collector electrode with the grid of described metal-oxide-semiconductor, described transistorized emitter and the equal ground connection of described input cathode, described the 4th resistance is connected between the first input end of an end of described sampling resistor and described amplifier, described the 5th resistance is connected between second input of the other end of described sampling resistor and described amplifier, and described capacitor is connected between second input of the first input end of described amplifier and described amplifier, described the 6th resistance is connected between the output of second input of described amplifier and described amplifier, described the 3rd resistance is connected between the first input end of the output of described amplifier and described comparator, described second resistance is connected between second input of described preset reference voltage and described comparator, and the output of described comparator is connected with described transistorized base stage.
5. intrinsic safety current foldback circuit according to claim 4 is characterized in that, described transistor is NPN transistor, and described metal-oxide-semiconductor is the N-channel MOS pipe.
6. according to each described intrinsic safety current foldback circuit of claim 1 to 5, it is characterized in that described power supply is mining power supply, described load is pit gear.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220745539 CN203039343U (en) | 2012-12-29 | 2012-12-29 | Intrinsic safe over-current protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220745539 CN203039343U (en) | 2012-12-29 | 2012-12-29 | Intrinsic safe over-current protection circuit |
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| CN203039343U true CN203039343U (en) | 2013-07-03 |
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| CN 201220745539 Expired - Fee Related CN203039343U (en) | 2012-12-29 | 2012-12-29 | Intrinsic safe over-current protection circuit |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103916012A (en) * | 2014-04-01 | 2014-07-09 | 江苏杰瑞科技集团有限责任公司 | Intrinsic safety power conversion device |
| CN104779577A (en) * | 2014-01-10 | 2015-07-15 | 海洋王（东莞）照明科技有限公司 | Over-current protection circuit |
| CN105139628A (en) * | 2015-08-19 | 2015-12-09 | 积成电子股份有限公司 | MBUS circuit applied to host end |
| CN107705763A (en) * | 2017-10-12 | 2018-02-16 | 深圳市华星光电技术有限公司 | Level shifting circuit and liquid crystal display device |
| CN108963999A (en) * | 2018-08-07 | 2018-12-07 | 中国航空工业集团公司雷华电子技术研究所 | A kind of Inrush current restraining device |
| CN109960302A (en) * | 2017-12-22 | 2019-07-02 | 和硕联合科技股份有限公司 | Current-limiting circuit structure and its control method |
-
2012
- 2012-12-29 CN CN 201220745539 patent/CN203039343U/en not_active Expired - Fee Related
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104779577A (en) * | 2014-01-10 | 2015-07-15 | 海洋王（东莞）照明科技有限公司 | Over-current protection circuit |
| CN104779577B (en) * | 2014-01-10 | 2018-11-06 | 海洋王（东莞）照明科技有限公司 | A kind of current foldback circuit |
| CN103916012A (en) * | 2014-04-01 | 2014-07-09 | 江苏杰瑞科技集团有限责任公司 | Intrinsic safety power conversion device |
| CN103916012B (en) * | 2014-04-01 | 2016-09-28 | 江苏杰瑞科技集团有限责任公司 | A kind of essential safety source conversion equipment |
| CN105139628A (en) * | 2015-08-19 | 2015-12-09 | 积成电子股份有限公司 | MBUS circuit applied to host end |
| CN107705763A (en) * | 2017-10-12 | 2018-02-16 | 深圳市华星光电技术有限公司 | Level shifting circuit and liquid crystal display device |
| CN107705763B (en) * | 2017-10-12 | 2020-04-28 | 深圳市华星光电技术有限公司 | Level conversion circuit and liquid crystal display device |
| CN109960302A (en) * | 2017-12-22 | 2019-07-02 | 和硕联合科技股份有限公司 | Current-limiting circuit structure and its control method |
| TWI672884B (en) * | 2017-12-22 | 2019-09-21 | 和碩聯合科技股份有限公司 | Current-limiting circuit structure and controlling method thereof |
| CN108963999A (en) * | 2018-08-07 | 2018-12-07 | 中国航空工业集团公司雷华电子技术研究所 | A kind of Inrush current restraining device |
| CN108963999B (en) * | 2018-08-07 | 2020-02-14 | 中国航空工业集团公司雷华电子技术研究所 | Surge current suppressor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130703 Termination date: 20151229 |
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| EXPY | Termination of patent right or utility model |