CN102420413A - Self-recovery stop type protection circuit for low-voltage and high-power safety barrier - Google Patents
Self-recovery stop type protection circuit for low-voltage and high-power safety barrier Download PDFInfo
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Abstract
The invention discloses a self-recovery stop type protection circuit for a low-voltage and high-power safety barrier. The self-recovery stop type protection circuit comprises a power switching circuit which is connected between a non intrinsic safety input circuit and a load and used for controlling switch-on and switch-off of a circuit, a current detection circuit which is connected with the power switching circuit and used for detecting current in the circuit in real time, an overcurent and shortcircuit judgment circuit which is connected with the current detection circuit, a switch-off pulse output circuit which is connected with the overcurent and shortcircuit judgment circuit, and a driving circuit which is connected with the switch-off pulse output circuit, wherein the input end of the overcurent and shortcircuit judgment circuit is connected with a reference circuit; the reference circuit is connected with the non intrinsic safety input circuit; and the driving circuit comprises an oscillation circuit for making the power switching circuit automatically re-switch on after the power switching circuit is switched off. The self-recovery stop type protection circuit has a simple structure, low power loss, high output power, a wide application range and high popularization and application value; the normal transmission of high-power electric energy is not influenced; and a requirement for intrinsic safety output is met.
Description
Technical field
The present invention relates to a kind of electronic product, especially relate to the cut-off type of the recovery certainly protective circuit of the low-pressure high-power guard grating between a kind of intrinsic safety equipment of power supply or electronic product and hazardous environment of the non-intrinsic safety type output that is connected security context.
Background technology
When non-intrinsically safe safety-type circuit is connected with the essential safe type circuit that works in hazardous environments such as colliery, petrochemical industry; Because signals such as the voltage of its output, electric current may be very big; Exceeded the essential safety scope; If be directly connected to the essential safe type circuit, the fault spark that causes possibly ignited the flammable explosive gas or the mixture of hazardous environment.Therefore, can be applied to safely in the dangerous type environment, just must between the intrinsically safe circuit of it and hazardous environment, introduce high-power guard grating, the fault spark energy is restricted in the certain limit in order to make non-intrinsically safe safety-type circuit.
Guard grating commonly used is at present mainly formed current limliting, pressure limiting circuit by resistance, voltage-stabiliser tube and transistor.Initial guard grating only adopts current-limiting resistance and Zener diode to constitute; Between the input power supply of non-intrinsically safe safety and output, seal in resistance, in order to the restriction maximum output current; Output also connects Zener diode in order to the restriction maximum output voltage, but owing to receive the restriction of power consumption, heating and Zener diode itself, output current is less usually, and output voltage is lower, only is applicable to lower powered load.In order to reduce loss, raising power output, the researcher begins to adopt resistance, voltage-stabiliser tube and transistor to constitute guard grating, but because transistor is operated in linear zone, the further raising of its power output also suffers restraints.So, need normal transmission that neither influences high-power electric energy of design, again can be with the high-power guard grating of fault energy limited in an enough little scope, to satisfy the requirement of explosion proof of hazardous environment to electric equipment.According to statistics; The all types of collieries of China have 2.6 ten thousand approximately at present; More than 3000 in wherein large and medium-sized colliery, key issue are extensively not adopt monitoring, supervisory control system, have a lot of potential safety hazards; And the Switching Power Supply that each is monitored, supervisory control system needs a playscript with stage directions matter safety-type at least, equipment improvement is extremely urgent.Therefore, design is applicable to that the low-pressure high-power guard grating of intrinsic safety type Switching Power Supply of risk environment is significant.
Summary of the invention
Technical problem to be solved by this invention is to above-mentioned deficiency of the prior art a kind of cut-off type of recovery certainly protective circuit of low-pressure high-power guard grating to be provided, and it is simple in structure, novel and reasonable design; It is convenient to realize, power loss is little, and power output is big; Do not influence the normal transmission of high-power electric energy, satisfy the requirement of intrinsic safety output, and allow the intrinsic safety electric current that output is bigger; Satisfy the requirement of explosion proof of hazardous environment to electric equipment, applied range, application value is high.
For solving the problems of the technologies described above; The technical scheme that the present invention adopts is: a kind of cut-off type of recovery certainly protective circuit of low-pressure high-power guard grating; Be connected between non-intrinsic safety input circuit and the load; It is characterized in that: comprise being connected between non-intrinsic safety input circuit and the load and being used for power switch circuit that control circuit opens or turn-off, joining and being used for the current detection circuit of real-time detection circuit size of current, joining and being used to judge overcurrent that overcurrent or short circuit phenomenon whether have occurred and short circuit decision circuit, joining and being used for when overcurrent or short circuit phenomenon take place that the shutoff impulse output circuit of pulse signal is turn-offed in output and join with the shutoff impulse output circuit and be used for the drive circuit that the power controlling switching circuit is opened or turn-offed with overcurrent and short circuit decision circuit with current detection circuit with power switch circuit; The input termination of said overcurrent and short circuit decision circuit also is used to overcurrent or the short circuit decision circuit provides the reference circuit of determinating reference; Said reference circuit and non-intrinsic safety input circuit join; Said drive circuit comprises and is used for closing to have no progeny at power switch circuit making power switch circuit recover the oscillating circuit of opening again automatically that the output of said power switch circuit and drive circuit joins.
Certainly the recovery cut-off type protective circuit of above-mentioned a kind of low-pressure high-power guard grating; It is characterized in that: said reference circuit comprises voltage-stabiliser tube ZD1, capacitor C 2 and resistance R 4; The cathode output end of said resistance R 4 one ends and non-intrinsic safety input circuit joins; The anode of the other end of said resistance R 4 and voltage-stabiliser tube ZD1 all joins with the input of overcurrent and short circuit decision circuit, the minus earth of said voltage-stabiliser tube ZD1, and said capacitor C 2 is parallelly connected with voltage-stabiliser tube ZD1.
Certainly the recovery cut-off type protective circuit of above-mentioned a kind of low-pressure high-power guard grating; It is characterized in that: said overcurrent and short circuit decision circuit comprise resistance R 5 and resistance R 6; One end of said resistance R 5 and the cathode output end of non-intrinsic safety input circuit join; One end of said resistance R 6 is the input of overcurrent and short circuit decision circuit, and the other end of the other end of said resistance R 5 and resistance R 6 joins and is the output of overcurrent and short circuit decision circuit.
Certainly the recovery cut-off type protective circuit of above-mentioned a kind of low-pressure high-power guard grating; It is characterized in that: said current detection circuit comprises resistance R 7; One end of said resistance R 7 and the cathode output end of power switch circuit join and ground connection, and an end of the other end of said resistance R 7 and resistance R 5 joins.
Certainly the recovery cut-off type protective circuit of above-mentioned a kind of low-pressure high-power guard grating; It is characterized in that: said shutoff impulse output circuit comprises comparator U1; The anode of the power input of said comparator U1 and voltage-stabiliser tube ZD1 joins; The output of the in-phase input end of said comparator U1 and overcurrent and short circuit decision circuit joins, the equal ground connection of the inverting input of said comparator U1 and earth terminal, and the output of said comparator U1 is for turn-offing the output of impulse output circuit.
Certainly the recovery cut-off type protective circuit of above-mentioned a kind of low-pressure high-power guard grating; It is characterized in that: said oscillating circuit comprises capacitor C 3 and resistance R 2; Said drive circuit also comprises NPN type triode VT2 and resistance R 3; One end of said resistance R 2 and the cathode output end of non-intrinsic safety input circuit join; One end of said capacitor C 3 joins with the output that turn-offs impulse output circuit, and the other end of the other end of said resistance R 2 and capacitor C 3 all joins with the base stage of NPN type triode VT2, and the emitter of said NPN type triode VT2 and an end of resistance R 3 join; The other end ground connection of said resistance R 3, the current collection of said NPN type triode VT2 is the output of drive circuit very.
Certainly the recovery cut-off type protective circuit of above-mentioned a kind of low-pressure high-power guard grating; It is characterized in that: said oscillating circuit comprises capacitor C 3 and resistance R 2; Said drive circuit also comprises NPN type triode VT2 and resistance R 3; One end of said resistance R 2 and the cathode output end of non-intrinsic safety input circuit join; One end of said capacitor C 3 joins with the output that turn-offs impulse output circuit, and the other end of the other end of said resistance R 2 and capacitor C 3 all joins with the base stage of NPN type triode VT2, the grounded emitter of said NPN type triode VT2; The collector electrode of said NPN type triode VT2 and an end of resistance R 3 join, and the other end of said resistance R 3 is the output of drive circuit.
Certainly the recovery cut-off type protective circuit of above-mentioned a kind of low-pressure high-power guard grating; It is characterized in that: said power switch circuit comprises resistance R 1 and positive-negative-positive triode VT1; The emitter of one end of said resistance R 1 and positive-negative-positive triode VT1 all joins with the cathode output end of non-intrinsic safety input circuit; The base stage of the other end of said resistance R 1 and positive-negative-positive triode VT1 is joined and is joined with the output of drive circuit, the current collection of said positive-negative-positive triode VT1 very power switch circuit cathode output end and join with the positive pole of load.
Certainly the recovery cut-off type protective circuit of above-mentioned a kind of low-pressure high-power guard grating; It is characterized in that: said power switch circuit comprises resistance R 1 and enhancement mode PMOS pipe VT3; The source electrode of one end of said resistance R 1 and enhancement mode PMOS pipe VT3 all joins with the cathode output end of non-intrinsic safety input circuit; The grid of the other end of said resistance R 1 and enhancement mode PMOS pipe VT3 joins and joins with the output of drive circuit, and the drain electrode of said enhancement mode PMOS pipe VT3 is the cathode output end of power switch circuit and joins with the positive pole of load.
Certainly the recovery cut-off type protective circuit of above-mentioned a kind of low-pressure high-power guard grating; It is characterized in that: said power switch circuit comprises resistance R 1 and meets the Darlington transistor VT4 that method constitutes by the PNP+NPN heteropolarity; One end of said resistance R 1 and the emitter of Darlington transistor VT4 all join with the cathode output end of non-intrinsic safety input circuit; The base stage of the other end of said resistance R 1 and Darlington transistor VT4 is joined and is joined with the output of drive circuit, the current collection of said Darlington transistor VT4 very power switch circuit cathode output end and join with the positive pole of load.
The present invention compared with prior art has the following advantages:
1, circuit structure of the present invention is simple, novel and reasonable design, and it is convenient to realize.
2, circuit working of the present invention is on off state, and power loss is little, and power output is big; Do not influence the normal transmission of high-power electric energy, when that is to say normal condition, the conducting of comparator output signal control NPN type triode; Thereby make the complete conducting of positive-negative-positive triode; When breaking down, comparator output signal control NPN type triode turn-offs, thereby positive-negative-positive triode (enhancement mode PMOS pipe or Darlington transistor) is turn-offed fully; Electric energy loss is very little in the circuit, can be applicable to high-power electric energy transmission occasion.
Oscillating circuit when 3, the present invention includes a short circuit or over-current state can make power switch circuit recover automatically to start, and promptly breaks down and when making electric energy output cut-out when circuit; The voltage Vi of non-intrinsic safety input circuit 7 outputs gives capacitor C 3 chargings through resistance R 2, when the voltage on the capacitor C 3 is elevated to can make NPN type triode VT2 conducting the time NPN type triode VT2 conducting again; And then make positive-negative-positive triode VT1 (enhancement mode PMOS pipe VT3 or Darlington transistor VT4) conducting again; The automatic recovering electrical energy output of circuit, if this moment, fault was eliminated, circuit is output normally; Otherwise circuit will be operated in oscillatory regime.
4, the present invention adopt positive-negative-positive triode VT1, enhancement mode PMOS pipe VT3 or by the PNP+NPN heteropolarity connect high speed such as Darlington transistor VT4 that method constitutes, the full-controlled switching element that hangs down conduction voltage drop constitutes power switch circuit; Through the current detection circuit size of electric current in the testing circuit in real time; When phenomenon such as the excessive or short trouble of output current (promptly when curtage surpass set point) occurring; Let full-controlled switching element turn-off fast; Thereby the output of fault restriction spark energy, oscillating circuit can make full-controlled switching element recover automatically to start, and this moment, the ifs circuit fault was eliminated the then normal output of circuit recovery; Otherwise circuit is operated in oscillatory regime always.The present invention satisfies the requirement of intrinsic safety output; And allow the intrinsic safety electric current that output is bigger; Be introduced between non-intrinsically safe fail safe circuit and the intrinsic safety circuit, can guarantee that the intrinsic safety circuit that joins with non-intrinsically safe circuit can work in the risk environment safely; The present invention satisfies the requirement of explosion proof of hazardous environment to electric equipment, can also be widely used in other electronic products.
In sum, the present invention is simple in structure, novel and reasonable design; It is convenient to realize, power loss is little, and power output is big; Do not influence the normal transmission of high-power electric energy, satisfy the requirement of intrinsic safety output, and allow the intrinsic safety electric current that output is bigger; Satisfy the requirement of explosion proof of hazardous environment to electric equipment, applied range, application value is high.
Through accompanying drawing and embodiment, technical scheme of the present invention is done further detailed description below.
Description of drawings
Fig. 1 is a schematic block circuit diagram of the present invention.
Fig. 2 is the circuit theory diagrams of the embodiment of the invention 1.
Fig. 3 is the circuit theory diagrams of the embodiment of the invention 2.
Fig. 4 is the circuit theory diagrams of the embodiment of the invention 3.
Fig. 5 is the circuit theory diagrams of the embodiment of the invention 4.
Fig. 6 is the circuit theory diagrams of the embodiment of the invention 5.
Fig. 7 is the circuit theory diagrams of the embodiment of the invention 6.
Description of reference numerals:
The 1-reference circuit; 2-overcurrent and short circuit decision circuit; 3-turn-offs impulse output circuit;
The 4-drive circuit; 5-power switch power supply; The 6-current detection circuit;
The non-intrinsic safety input circuit of 7-; The 8-load.
Embodiment
As shown in Figure 1; The present invention is connected between non-intrinsic safety input circuit 7 and the load 8; Comprise be connected between non-intrinsic safety input circuit 7 and the load 8 and be used for power switch circuit 5 that control circuit opens or turn-off, join with power switch circuit 5 and be used for the current detection circuit 6 of real-time detection circuit size of current, join with current detection circuit 6 and be used to judge overcurrent that overcurrent or short circuit phenomenon whether have occurred and short circuit decision circuit 2, join and be used for overcurrent and short circuit decision circuit 2 when overcurrent or short circuit phenomenon take place output turn-off pulse signal shutoff impulse output circuit 3 and with turn-off the drive circuit 4 that impulse output circuit 3 joins and is used for 5 shutoffs of power controlling switching circuit or opens; The input of said overcurrent and short circuit decision circuit 2 is connected to and is used to the reference circuit 1 that overcurrent or short circuit decision circuit 2 provide determinating reference; Said reference circuit 1 joins with non-intrinsic safety input circuit 7; Said drive circuit 4 comprises and is used for closing the oscillating circuit of having no progeny the automatic again recovery of power switch circuit 5 being opened at power switch circuit 5 that said power switch circuit 5 joins with the output of drive circuit 4.
In conjunction with Fig. 2; In the present embodiment; Said reference circuit 1 comprises voltage-stabiliser tube ZD1, capacitor C 2 and resistance R 4, and the cathode output end of said resistance R 4 one ends and non-intrinsic safety input circuit 7 joins, and the anode of the other end of said resistance R 4 and voltage-stabiliser tube ZD1 all joins with the input of overcurrent and short circuit decision circuit 2; The minus earth of said voltage-stabiliser tube ZD1, said capacitor C 2 is parallelly connected with voltage-stabiliser tube ZD1.
In the present embodiment; Said overcurrent and short circuit decision circuit 2 comprise resistance R 5 and resistance R 6; One end of said resistance R 5 and the cathode output end of non-intrinsic safety input circuit 7 join; One end of said resistance R 6 is the input of overcurrent and short circuit decision circuit 2, and the other end of the other end of said resistance R 5 and resistance R 6 joins and is the output of overcurrent and short circuit decision circuit 2.
In the present embodiment, said current detection circuit 6 comprises resistance R 7, and an end of said resistance R 7 and the cathode output end of power switch circuit 5 join and ground connection, and an end of the other end of said resistance R 7 and resistance R 5 joins.
In the present embodiment; Said shutoff impulse output circuit 3 comprises comparator U1; The anode of the power input of said comparator U1 and voltage-stabiliser tube ZD1 joins; The output of the in-phase input end of said comparator U1 and overcurrent and short circuit decision circuit 2 joins, the equal ground connection of the inverting input of said comparator U1 and earth terminal, and the output of said comparator U1 is for turn-offing the output of impulse output circuit 3.
In the present embodiment; Said oscillating circuit comprises capacitor C 3 and resistance R 2; Said drive circuit 4 also comprises NPN type triode VT2 and resistance R 3, and an end of said resistance R 2 and the cathode output end of non-intrinsic safety input circuit 7 join, and an end of said capacitor C 3 joins with the output that turn-offs impulse output circuit 3; The other end of the other end of said resistance R 2 and capacitor C 3 all joins with the base stage of NPN type triode VT2; The emitter of said NPN type triode VT2 and an end of resistance R 3 join, the other end ground connection of said resistance R 3, and the current collection of said NPN type triode VT2 is the output of drive circuit 4 very.
In the present embodiment; Said power switch circuit 5 comprises resistance R 1 and positive-negative-positive triode VT1; The emitter of one end of said resistance R 1 and positive-negative-positive triode VT1 all joins with the cathode output end of non-intrinsic safety input circuit 7; The base stage of the other end of said resistance R 1 and positive-negative-positive triode VT1 is joined and is joined with the output of drive circuit 4, the current collection of said positive-negative-positive triode VT1 very power switch circuit 5 cathode output end and join with the positive pole of load 8.
In conjunction with Fig. 3, what present embodiment and embodiment 1 were different is: the grounded emitter of said NPN type triode VT2, and the collector electrode of said NPN type triode VT2 and an end of resistance R 3 join, and the other end of said resistance R 3 is the output of drive circuit 4.The remaining circuit structure is all identical with embodiment 1.
In conjunction with Fig. 4; What present embodiment and embodiment 1 were different is: said power switch circuit 5 comprises resistance R 1 and enhancement mode PMOS pipe VT3; The source electrode of one end of said resistance R 1 and enhancement mode PMOS pipe VT3 all joins with the cathode output end of non-intrinsic safety input circuit 7; The grid of the other end of said resistance R 1 and enhancement mode PMOS pipe VT3 joins and joins with the output of drive circuit 4, and the drain electrode of said enhancement mode PMOS pipe VT3 is the cathode output end of power switch circuit 5 and joins with the positive pole of load 8.The remaining circuit structure is all identical with embodiment 1.
In conjunction with Fig. 5; What present embodiment and embodiment 1 were different is: said power switch circuit 5 comprises resistance R 1 and meets the Darlington transistor VT4 that method constitutes by the PNP+NPN heteropolarity; One end of said resistance R 1 and the emitter of Darlington transistor VT4 all join with the cathode output end of non-intrinsic safety input circuit 7; The base stage of the other end of said resistance R 1 and Darlington transistor VT4 is joined and is joined with the output of drive circuit 4, the current collection of said Darlington transistor VT4 very power switch circuit 5 cathode output end and join with the positive pole of load 8.The remaining circuit structure is all identical with embodiment 1.
In conjunction with Fig. 6; What present embodiment and embodiment 2 were different is: said power switch circuit 5 comprises resistance R 1 and enhancement mode PMOS pipe VT3; The source electrode of one end of said resistance R 1 and enhancement mode PMOS pipe VT3 all joins with the cathode output end of non-intrinsic safety input circuit 7; The grid of the other end of said resistance R 1 and enhancement mode PMOS pipe VT3 joins and joins with the output of drive circuit 4, and the drain electrode of said enhancement mode PMOS pipe VT3 is the cathode output end of power switch circuit 5 and joins with the positive pole of load 8.The remaining circuit structure is all identical with embodiment 1.The remaining circuit structure is all identical with embodiment 2.
In conjunction with Fig. 7; What present embodiment and embodiment 2 were different is: said power switch circuit 5 comprises resistance R 1 and meets the Darlington transistor VT4 that method constitutes by the PNP+NPN heteropolarity; One end of said resistance R 1 and the emitter of Darlington transistor VT4 all join with the cathode output end of non-intrinsic safety input circuit 7; The base stage of the other end of said resistance R 1 and Darlington transistor VT4 is joined and is joined with the output of drive circuit 4, the current collection of said Darlington transistor VT4 very power switch circuit 5 cathode output end and join with the positive pole of load 8.The remaining circuit structure is all identical with embodiment 2.
Wherein, among Fig. 2～Fig. 7, the voltage of non-intrinsic safety input circuit 7 outputs all is expressed as Vi, and load 8 all is expressed as RL.
The operation principle of the present invention and the course of work are: after the voltage Vi of non-intrinsic safety input circuit 7 outputs sends into circuit; Under the normal condition; The electric current that flows through resistance R 7 is almost nil; The voltage of that end that resistance R 5 is connected with resistance R 7 in overcurrent and the short circuit decision circuit 2 can be thought no-voltage, and the voltage of that end that the anode of resistance R 6 and voltage-stabiliser tube ZD1 joins is for can be to positive voltage signal of in-phase input end input of comparator U1 after relatively through resistance R 5 and resistance R 6 mutual superposition on the occasion of, the voltage at these two ends; The output output high level of comparator U1; This high level makes NPN type triode VT2 conducting, thereby makes positive-negative-positive triode VT1 (enhancement mode PMOS pipe VT3 or Darlington transistor VT4) conducting, and electric energy is normally exported in the circuit; When phenomenon such as the excessive or short trouble of output current (promptly when curtage surpass set point) occurring; Can produce a bigger negative pressure drop on the resistance R 7 in the current detection circuit 6; The voltage that overcurrent and short circuit decision circuit 2 provide this voltage and reference circuit 1 compares after the judgement result exported to and turn-offs impulse output circuit 3; Make the shutoff pulse of the output output low level of comparator U1; NPN type triode VT2 turn-offs, thereby positive-negative-positive triode VT1 (enhancement mode PMOS pipe VT3 or Darlington transistor VT4) is turn-offed, and circuit stops electric energy output; At this moment; The voltage Vi of non-intrinsic safety input circuit 7 outputs gives capacitor C 3 chargings through resistance R 2; When the voltage on the capacitor C 3 is elevated to can make NPN type triode VT2 conducting the time; NPN type triode VT2 conducting again, thus make positive-negative-positive triode VT1 (enhancement mode PMOS pipe VT3 or Darlington transistor VT4) conducting again, and circuit recovers output; If phenomenons such as the excessive or short trouble of electric current this moment have been eliminated; The then stable output of circuit; Otherwise positive-negative-positive triode VT1 (enhancement mode PMOS pipe VT3 or Darlington transistor VT4) can turn-off again after conducting, repeats then to turn-off behind the above-mentioned turn on process again; Vibration so always, the output of fault restriction spark energy.The present invention can be limited in the fault spark energy in the enough little scope under the situation that does not influence high-power energy normal transmission, has satisfied the requirement of essential safety.
Among embodiment 1, embodiment 3 and the embodiment 4, the emitter of said NPN type triode VT2 is all through resistance R 3 ground connection, the current collection of said NPN type triode VT2 very drive circuit 4 output and join with power switch circuit 2.Among embodiment 2, embodiment 5 and the embodiment 6, the collector electrode of said NPN type triode VT2 and an end of resistance R 3 join, and the other end of said resistance R 3 is the output of drive circuit 4 and joins with power switch circuit 2.Among embodiment 1, embodiment 3 and embodiment 4 and embodiment 2, embodiment 5 and the embodiment 6 resistance R 3 to connect method different; But its effect all is the electric current that NPN type triode VT2 is flow through in restriction; Prevent to cross its damage of ambassador because of the electric current that flows through NPN type triode VT2, two kinds connect method and can both play good metering function.
Among embodiment 1 and the embodiment 2, the full-controlled switching element in the power switch circuit 5 adopts positive-negative-positive triode VT1, its objective is the voltage difference that reduces between input voltage Vi and the output voltage V o, reduces the wastage, and has improved power-efficient.
Among embodiment 3 and the embodiment 5, the full-controlled switching element in the power switch circuit 5 adopts enhancement mode PMOS pipe VT3, and enhancement mode PMOS pipe belongs to the unipolarity device; When turning on and off, it have only majority carrier to participate in conduction; So, switch saved the reverse recovery time of electronics when turn-offing than triode, and faster from the switching speed that makes circuit, fault power transfer in the restricting circuits fast; But because metal-oxide-semiconductor is the voltage driven type device; Its driving voltage should be greater than 5V, and generally speaking the price of metal-oxide-semiconductor is higher than triode, thus switching speed require high, driving voltage is big and cost do not required in can adopt.
Among embodiment 4 and the embodiment 6; Full-controlled switching element in the power switch circuit 5 adopts and meets the Darlington transistor VT4 that method constitutes by the PNP+NPN heteropolarity; Darlington transistor is constituted by two triodes; Its multiplication factor equals the product of the multiplication factor of two triodes, and its drive current is very little, and very little electric current just can drive circuit works; But because it is that to constitute switching speed by two triodes slower than triode, thus at drive current very little and switching speed do not required in can adopt.
In sum; The present invention adopts at a high speed, the full-controlled switching element of low conduction voltage drop (positive-negative-positive triode VT1, enhancement mode PMOS pipe VT3 or Darlington transistor VT4) constitutes power switch circuit 5, through current detection circuit 6 size of electric current in the testing circuit in real time, when phenomenon such as the excessive or short trouble of output current (promptly when curtage above set point) occurring; Let full-controlled switching element turn-off fast; Thereby the output of fault restriction spark energy, oscillating circuit can make full-controlled switching element recover automatically to start, and this moment, the ifs circuit fault was eliminated the then normal output of circuit recovery; Otherwise circuit is operated in oscillatory regime always.The present invention satisfies the requirement of intrinsic safety output; And allow bigger intrinsic safety electric current; Be introduced between non-intrinsically safe fail safe circuit and the intrinsic safety circuit, can guarantee that the intrinsically safe power supply that joins with non-intrinsically safe circuit can work in the risk environment safely; The present invention satisfies the requirement of explosion proof of hazardous environment to electric equipment, can also be widely used in other electronic products.
The above; It only is preferred embodiment of the present invention; Be not that the present invention is done any restriction, every technical spirit changes any simple modification, change and the equivalent structure that above embodiment did according to the present invention, all still belongs in the protection range of technical scheme of the present invention.
Claims (10)
1. the cut-off type of the recovery certainly protective circuit of a low-pressure high-power guard grating; Be connected between non-intrinsic safety input circuit (7) and the load (8); It is characterized in that: comprise being connected between non-intrinsic safety input circuit (7) and the load (8) and being used for power switch circuit (5) that control circuit opens or turn-off, joining and being used for the current detection circuit (6) of real-time detection circuit size of current, joining and being used to judge overcurrent that overcurrent or short circuit phenomenon whether have occurred and short circuit decision circuit (2), joining and being used for when overcurrent or short circuit phenomenon take place that the shutoff impulse output circuit (3) of pulse signal is turn-offed in output and join with shutoff impulse output circuit (3) and be used for the drive circuit (4) that power controlling switching circuit (5) is opened or turn-offed with overcurrent and short circuit decision circuit (2) with current detection circuit (6) with power switch circuit (5); The input of said overcurrent and short circuit decision circuit (2) is connected to and is used to the reference circuit (1) that overcurrent or short circuit decision circuit (2) provide determinating reference; Said reference circuit (1) joins with non-intrinsic safety input circuit (7); Said drive circuit (4) comprises and is used for closing the oscillating circuit of having no progeny the automatic again recovery of power switch circuit (5) being opened at power switch circuit (5) that said power switch circuit (5) joins with the output of drive circuit (4).
2. according to the cut-off type of the recovery certainly protective circuit of the described a kind of low-pressure high-power guard grating of claim 1; It is characterized in that: said reference circuit (1) comprises voltage-stabiliser tube ZD1, capacitor C 2 and resistance R 4; The cathode output end of said resistance R 4 one ends and non-intrinsic safety input circuit (7) joins; The anode of the other end of said resistance R 4 and voltage-stabiliser tube ZD1 all joins with the input of overcurrent and short circuit decision circuit (2), the minus earth of said voltage-stabiliser tube ZD1, and said capacitor C 2 is parallelly connected with voltage-stabiliser tube ZD1.
3. according to the cut-off type of the recovery certainly protective circuit of the described a kind of low-pressure high-power guard grating of claim 2; It is characterized in that: said overcurrent and short circuit decision circuit (2) comprise resistance R 5 and resistance R 6; The cathode output end of one end of said resistance R 5 and non-intrinsic safety input circuit (7) joins; One end of said resistance R 6 is the input of overcurrent and short circuit decision circuit (2), and the other end of the other end of said resistance R 5 and resistance R 6 joins and is the output of overcurrent and short circuit decision circuit (2).
4. according to the cut-off type of the recovery certainly protective circuit of the described a kind of low-pressure high-power guard grating of claim 3; It is characterized in that: said current detection circuit (6) comprises resistance R 7; The cathode output end of one end of said resistance R 7 and power switch circuit (5) joins and ground connection, and an end of the other end of said resistance R 7 and resistance R 5 joins.
5. according to the cut-off type of the recovery certainly protective circuit of the described a kind of low-pressure high-power guard grating of claim 4; It is characterized in that: said shutoff impulse output circuit (3) comprises comparator U1; The anode of the power input of said comparator U1 and voltage-stabiliser tube ZD1 joins; The output of the in-phase input end of said comparator U1 and overcurrent and short circuit decision circuit (2) joins; The equal ground connection of the inverting input of said comparator U1 and earth terminal, the output of said comparator U1 is for turn-offing the output of impulse output circuit (3).
6. according to the cut-off type of the recovery certainly protective circuit of the described a kind of low-pressure high-power guard grating of claim 5; It is characterized in that: said oscillating circuit comprises capacitor C 3 and resistance R 2; Said drive circuit (4) also comprises NPN type triode VT2 and resistance R 3; The cathode output end of one end of said resistance R 2 and non-intrinsic safety input circuit (7) joins; One end of said capacitor C 3 joins with the output that turn-offs impulse output circuit (3), and the other end of the other end of said resistance R 2 and capacitor C 3 all joins with the base stage of NPN type triode VT2, and the emitter of said NPN type triode VT2 and an end of resistance R 3 join; The other end ground connection of said resistance R 3, the current collection of said NPN type triode VT2 is the output of drive circuit (4) very.
7. according to the cut-off type of the recovery certainly protective circuit of the described a kind of low-pressure high-power guard grating of claim 5; It is characterized in that: said oscillating circuit comprises capacitor C 3 and resistance R 2; Said drive circuit (4) also comprises NPN type triode VT2 and resistance R 3; The cathode output end of one end of said resistance R 2 and non-intrinsic safety input circuit (7) joins; One end of said capacitor C 3 joins with the output that turn-offs impulse output circuit (3), and the other end of the other end of said resistance R 2 and capacitor C 3 all joins with the base stage of NPN type triode VT2, the grounded emitter of said NPN type triode VT2; The collector electrode of said NPN type triode VT2 and an end of resistance R 3 join, and the other end of said resistance R 3 is the output of drive circuit (4).
8. according to the cut-off type of the recovery certainly protective circuit of claim 6 or 7 described a kind of low-pressure high-power guard gratings; It is characterized in that: said power switch circuit (5) comprises resistance R 1 and positive-negative-positive triode VT1; The emitter of one end of said resistance R 1 and positive-negative-positive triode VT1 all joins with the cathode output end of non-intrinsic safety input circuit (7); The base stage of the other end of said resistance R 1 and positive-negative-positive triode VT1 is joined and is joined with the output of drive circuit (4), the current collection of said positive-negative-positive triode VT1 very power switch circuit (5) cathode output end and join with the positive pole of load (8).
9. according to the cut-off type of the recovery certainly protective circuit of claim 6 or 7 described a kind of low-pressure high-power guard gratings; It is characterized in that: said power switch circuit (5) comprises resistance R 1 and enhancement mode PMOS pipe VT3; The source electrode of one end of said resistance R 1 and enhancement mode PMOS pipe VT3 all joins with the cathode output end of non-intrinsic safety input circuit (7); The grid of the other end of said resistance R 1 and enhancement mode PMOS pipe VT3 joins and joins with the output of drive circuit (4), and the drain electrode of said enhancement mode PMOS pipe VT3 is the cathode output end of power switch circuit (5) and joins with the positive pole of load (8).
10. according to the cut-off type of the recovery certainly protective circuit of claim 6 or 7 described a kind of low-pressure high-power guard gratings; It is characterized in that: said power switch circuit (5) comprises resistance R 1 and meets the Darlington transistor VT4 that method constitutes by the PNP+NPN heteropolarity; One end of said resistance R 1 and the emitter of Darlington transistor VT4 all join with the cathode output end of non-intrinsic safety input circuit (7); The base stage of the other end of said resistance R 1 and Darlington transistor VT4 is joined and is joined with the output of drive circuit (4), the current collection of said Darlington transistor VT4 very power switch circuit (5) cathode output end and join with the positive pole of load (8).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110451994.5A CN102420413B (en) | 2011-12-29 | 2011-12-29 | Self-recovery stop type protection circuit for low-voltage and high-power safety barrier |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110451994.5A CN102420413B (en) | 2011-12-29 | 2011-12-29 | Self-recovery stop type protection circuit for low-voltage and high-power safety barrier |
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| Publication Number | Publication Date |
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| CN102420413A true CN102420413A (en) | 2012-04-18 |
| CN102420413B CN102420413B (en) | 2014-03-05 |
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|---|---|---|---|
| CN201110451994.5A Expired - Fee Related CN102420413B (en) | 2011-12-29 | 2011-12-29 | Self-recovery stop type protection circuit for low-voltage and high-power safety barrier |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102820638A (en) * | 2012-08-09 | 2012-12-12 | 深圳市九洲电器有限公司 | Overcurrent protection device and electronic equipment |
| CN104811173A (en) * | 2015-02-25 | 2015-07-29 | 雅安小航电器有限责任公司 | Simple driving circuit with load short circuit protection and self recovery functions |
| CN105790207A (en) * | 2016-05-20 | 2016-07-20 | 中国矿业大学 | High-power cut-off type safety barrier |
| CN106972456A (en) * | 2017-04-28 | 2017-07-21 | 西安科技大学 | A kind of self-oscillation hiccup formula short-circuit protection circuit and its design method |
| CN107623511A (en) * | 2016-07-14 | 2018-01-23 | 上海沪工汽车电器有限公司 | A kind of vehicle solid-state relay for including NMOS tube with overcurrent protection |
| CN107623510A (en) * | 2016-07-14 | 2018-01-23 | 上海沪工汽车电器有限公司 | A kind of vehicle solid-state relay for including PMOS with overcurrent protection |
| CN109981090A (en) * | 2019-04-26 | 2019-07-05 | 福建科立讯通信有限公司 | A kind of Sofe Switch electromechanics road that can restore on-off state automatically |
| CN115561560A (en) * | 2022-10-21 | 2023-01-03 | 南京信息工程大学 | Pure hardware implementation control circuit and control method for power device aging test |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102820638A (en) * | 2012-08-09 | 2012-12-12 | 深圳市九洲电器有限公司 | Overcurrent protection device and electronic equipment |
| CN102820638B (en) * | 2012-08-09 | 2014-10-29 | 深圳市九洲电器有限公司 | Overcurrent protection device and electronic equipment |
| CN104811173A (en) * | 2015-02-25 | 2015-07-29 | 雅安小航电器有限责任公司 | Simple driving circuit with load short circuit protection and self recovery functions |
| CN104811173B (en) * | 2015-02-25 | 2018-10-12 | 雅安小航电器有限责任公司 | Simple driving circuit with load short circuits protection and self-recovering function |
| CN105790207A (en) * | 2016-05-20 | 2016-07-20 | 中国矿业大学 | High-power cut-off type safety barrier |
| CN107623510A (en) * | 2016-07-14 | 2018-01-23 | 上海沪工汽车电器有限公司 | A kind of vehicle solid-state relay for including PMOS with overcurrent protection |
| CN107623511A (en) * | 2016-07-14 | 2018-01-23 | 上海沪工汽车电器有限公司 | A kind of vehicle solid-state relay for including NMOS tube with overcurrent protection |
| CN107623511B (en) * | 2016-07-14 | 2020-10-30 | 上海沪工汽车电器有限公司 | Vehicle solid-state relay with overcurrent protection and NMOS (N-channel metal oxide semiconductor) tube |
| CN106972456A (en) * | 2017-04-28 | 2017-07-21 | 西安科技大学 | A kind of self-oscillation hiccup formula short-circuit protection circuit and its design method |
| CN106972456B (en) * | 2017-04-28 | 2019-08-09 | 西安科技大学 | A kind of self-oscillation hiccup formula short-circuit protection circuit and its design method |
| CN109981090A (en) * | 2019-04-26 | 2019-07-05 | 福建科立讯通信有限公司 | A kind of Sofe Switch electromechanics road that can restore on-off state automatically |
| CN109981090B (en) * | 2019-04-26 | 2022-10-25 | 福建科立讯通信有限公司 | Soft on-off circuit capable of automatically recovering on-off state |
| CN115561560A (en) * | 2022-10-21 | 2023-01-03 | 南京信息工程大学 | Pure hardware implementation control circuit and control method for power device aging test |
| CN115561560B (en) * | 2022-10-21 | 2023-09-22 | 南京信息工程大学 | Pure hardware implementation control circuit and control method for power device aging test |
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| CN102420413B (en) | 2014-03-05 |
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