CN103578218B - The line drive circuit of fire alarm system and corresponding fire alarm system - Google Patents
The line drive circuit of fire alarm system and corresponding fire alarm system Download PDFInfo
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- CN103578218B CN103578218B CN201210270657.0A CN201210270657A CN103578218B CN 103578218 B CN103578218 B CN 103578218B CN 201210270657 A CN201210270657 A CN 201210270657A CN 103578218 B CN103578218 B CN 103578218B
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
- G08B25/01—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium
- G08B25/04—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium using a single signalling line, e.g. in a closed loop
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
- G08B29/02—Monitoring continuously signalling or alarm systems
- G08B29/06—Monitoring of the line circuits, e.g. signalling of line faults
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Abstract
The present invention proposes a kind of drive circuit for fire alarm system and driving method. This drive circuit comprises: current generating circuit, it can optionally provide the first electric current I to described circuitN1With the second electric current IALARMOne of in, wherein, described the first electric current IN1As the circuit monitoring electric current under normal operating conditions, described the second electric current IALARMBe greater than described the first electric current IN1; Testing circuit, for the line voltage distribution V detecting on described circuitLineDuring lower than a threshold value Vth, control current generating circuit and provide the second electric current I to described circuitALARM, wherein said threshold value VthSubnormal line voltage distribution but the maximum alarm voltage that indicates on described circuit during higher than described fire detector alarm.
Description
Technical field
The present invention relates in general to condition of a fire alarm field, relates in particular to line drive circuit and driving side in a kind of fire alarm systemMethod.
Background technology
Automatic fire alarm system, is called for short fire alarm system, is people for early detection, the circular condition of a fire, and has taked in timeEffect measure, as controlled and putting out the condition of a fire, and is arranged in building or other residing a kind of automatic fire-fighting facility. At presentMost of building, as being provided with fire alarm system in office building, hotel, megastore.
Figure 1A schematically shows the general formation of fire alarm system. As shown in Figure 1A, during fire alarm system 100 generally comprisesCentre control system 110 and by circuit Line be connected to central control system 110 multiple fire detectors 120 and/orMultiple manual alarms 130 etc. Fire detector 120 and manual alarm 130 all pass alarm signal via circuit LineGive central control system 110. Central control system 110 takes in response to this alarm signal the measure of putting out a fire accordingly automaticallyAnd means of communication. Thus, adopt the fire alarm system shown in Figure 1A can realize automatic alarm, self-extinguishing, safe escapeInduction, systematic procedure show, fire archieves is managed etc., thereby form a complete fire control system.
Central control system 110 in Figure 1A can adopt Alternating Current Power Supply 111 or storage battery power supply 112. Here general,Require the battery 112 of central control system 110 can maintain the fire monitoring work that system reaches 72 hours. OneA little countries also require battery 112 can maintain the alarm status of about half an hour. In order to reach above-mentioned requirements, central authorities' controlSystem 110 processed needs power saving as much as possible.
In Figure 1A, fire detector 120 is instruments of detection of fires. Due to the stage occurring in the condition of a fire, will follow productRaw smog, high temperature, flame etc. These cigarettes, light and heat can pass through smoke detector 120(" S ") or hygrosensor120(" H ") change signal of telecommunication warning into and make central control system automatically start extinguishing device, fire extinguishing in time. Central authorities' controlSystem 110 processed provides driving to each fire detector 120 or manual alarm 130 via circuit Line, so that its acquisitionEnough electric energy, normally to work. Meanwhile, central control system 110 also periodic Monitoring Line Line whether occur breakingRoad or short trouble, to ensure the normal operation of fire detector 120 and manual alarm 130.
Figure 1B has specifically illustrated the annexation of for example fire detector 120 and central control system 110. Shown in Figure 1BExample in, multiple fire detectors 120 are connected in parallel between circuit Line+ and Line-, and in the far-end termination of circuit LineThere is termination components (EOL:EndofLine). Here termination components EOL can be resistance element, for detection of circuit isNo have a fault. Particularly, in the time that opening circuit appears in circuit Line, the line resistance detecting from central control system 110 sides willHigher than the resistance of EOL; In the time that short circuit appears in circuit, the line resistance detecting from central control system 110 sides will be less thanThe resistance of EOL. Thus, whether EOL can contribute to detection line normal.
Central control system 110 is gone back real time monitoring line voltage distribution VLineTo whether there is alarm on Monitoring Line. Fire detectionDevice 120 can send alarm signal in the time detecting the condition of a fire on circuit Line, for example, drag down line voltage distribution VLine. Fig. 2 A andFig. 2 B exemplarily illustrates the alarm indicating mode of two conventional at present class fire detectors 120. Fire alarm shown in Fig. 2 A is visitedSurvey device 120-1 actuating switch K1 in the time that its sensing module 220 detects the condition of a fire, this K switch 1 and a Zener diode are (anti-Be about for example 5.6V to breakdown voltage) be connected between circuit Line+ and Line-. Thus, K switch 1 conducting makes circuitVoltage is pulled down to the breakdown reverse voltage of this Zener diode, i.e. 5.6V from normal for example 24V. Thus, center-control systemSystem 110 can detect the decline of this line voltage distribution and find alarm.
Fig. 2 B shows the another kind of alarm mode of fire detector 120-2. As shown in Figure 2 B, at its sensing module 220Actuating switch K2 while detecting the condition of a fire, this K switch 2 and a small resistor (for example 450ohm) are connected on circuit Line+And between Line-. Like this, for example 30mA electric current when K switch 2 conducting on circuit can pour into small resistor, and makes thusLine voltage distribution is pulled down to about 12V left and right from 24V. Now, also need to continue to maintain large electric current on circuit and flow through this small resistor,Thereby the voltage of this about 12V is maintained a period of time, to guarantee that central control system 110 can detect current alarm.Otherwise, if powering on to flow down, circuit falls, and small resistor both end voltage declines, and fire detector 120-2 can trigger heavily mistakenlyPut mechanism (RESET), and cause missing current alarm.
In existing central control system, general respectively for the different fire detector design shown in Fig. 2 A and Fig. 2 BDrive circuit, and identify in advance the type that connected fire detector is Fig. 2 A with wire jumper or software RM,Or the type of Fig. 2 B. Existing another kind of settling mode is that higher electric current is provided all the time on the line, to avoid above-mentionedThe generation that mistake is reset. But, consider the requirement of central control system 110 to power saving, what this mode neither be optimum.
Summary of the invention
The above-mentioned defect of considering prior art, embodiments of the invention have proposed the drive circuit in a kind of fire alarm system, shouldDrive circuit is for driving the circuit that is connected with one or more fire detectors. Adopt this drive circuit can be adaptivelySupport the fire detector of two types shown in Fig. 2 A and Fig. 2 B, but also can reach the object of power saving. In the present inventionA kind of drive circuit of fire alarm system has been proposed in an embodiment. This drive circuit is for being provided to electric energy to be connected with oneOr on the circuit of multiple fire detectors, this drive circuit comprises: current generating circuit, it can be optionally to described lineRoad provides the first electric current IN1With the second electric current IALARMOne of the two, wherein, described the first electric current IN1As normal work shapeCircuit monitoring electric current under state, described the second electric current IALARMBe greater than described the first electric current IN1; Testing circuit, for detection ofWhether the line voltage distribution on described circuit lower than a threshold value, and, controls during lower than described threshold value Vth at described line voltage distributionDescribed current generating circuit provides the second electric current I to described circuit LineALARM, wherein said threshold value VthSubnormal lineRoad voltage but the maximum alarm voltage V that indicates on described circuit during higher than described fire detector alarmAlarm. Preferably,Described the second electric current IALARMSize make described maximum alarm voltage VAlarmCan maintain a predetermined amount of time, to makeDescribed fire alarm system detects described alarm voltage VAlarm. More preferably, when the distal end of described circuit Line be connected toWhen a few termination components (EOL), described the first electric current IN1> (can be connected to the maximum of the fire detector of described circuitThe minimum forward current of the quiescent current+described termination components EOL of number × each fire detector).
Above-mentioned drive circuit can provide little monitor current I at monitor stagesN1, and provide larger alarm electricity in the alert phraseStream IALARM. Can make like this fire alarm system the alarm signal of dissimilar fire detector be detected, the while is all rightReduce to a certain extent the energy consumption of fire alarm system. Due to the more efficiently power saving of this drive circuit, therefore correspondinglyThe battery of fire alarm system is maintained the longer working time.
In one embodiment of the invention, described testing circuit comprises: threshold decision circuit, be connected to described circuit Line upper,For judging described line voltage distribution V with hardware modeLineWhether lower than described threshold value Vth; Control circuit, at described lineRoad voltage VLineLower than described threshold value VthTime, control described current generating circuit, make it from the first electric current I is providedN1SwitchTo the second electric current I is providedALARM. Because adopting hardware detecting circuit, above-mentioned drive circuit realizes threshold decision and FEEDBACK CONTROL,Therefore this drive circuit can detect alarm signal within the extremely short time, and larger alarm electric current I is provided immediatelyALARMMaintain the alarm signal of fire detector as shown in Figure 2 B.
In another embodiment of the present invention, described threshold decision circuit comprises: series arm, and described in be coupled at its two endsLine voltage distribution VLine, this series arm comprises at least one Zener diode and the first resistance, described at least one voltage stabilizing two utmost pointThe breakdown reverse voltage sum of pipe equals described threshold value Vth; And described control circuit is by described the first resistance and described voltage stabilizingBetween diode, the voltage of tie point is as threshold decision result, for controlling described current generating circuit. Preferably, described inControl circuit comprises for the on-off circuit that is switching value by described threshold decision results conversion. Adopt in this embodiment simpleZener diode as threshold decision element, be characterized in simple in structure, fast response time.
In one embodiment of the invention, preferably, described current generating circuit is current source. More preferably, described electricityStream source comprises: triode, connects into common emitter circuit, for providing current to described circuit Line; Variable resistance circuit,It is connected on the emitter-base bandgap grading of described triode, and its resistance sizes can at least be cut between the first resistance value and the second resistance valueChange; Voltage control circuit, for making the voltage stabilization at described variable resistance circuit two ends at a predetermined voltage; Wherein,Described variable resistance circuit switches the size of its resistance value in response to the control signal of described testing circuit. Preferably, described inVariable resistance circuit comprises: at least two resistance branch that are connected in parallel are provided with one in one of them resistance branchIndividual controlled switch, described controlled switch is closed in response to the control signal of described testing circuit.
In another embodiment of the present invention, described current source comprises: triode, connects into common emitter circuit, for drawingElectric current on described circuit Line, is connected with the second resistance on its emitter-base bandgap grading; Voltage control circuit, for controlling described the second electricityThe voltage stabilization at resistance two ends is one of in the first magnitude of voltage and second voltage value, and wherein, described voltage control circuit is in response to instituteState the control signal of testing circuit and the first magnitude of voltage is switched to second voltage value.
A kind of fire alarm system has also been proposed in another embodiment. This fire alarm system comprises: one or more fireAlert detector, for surveying whether occur the condition of a fire in its region; Drive circuit as above, for providing electric energyTo being connected with on the circuit of one or more fire detectors; Termination components (EOL), is connected to the far-end of described circuit, usesIn circuit described in termination. Preferably, described termination components (EOL) is transient state Zener diode (TVS). Preferably, fireAlert detector comprises that at least one needs extra current to maintain the detector of its alarm voltage in the time of alarm. Adopt this fire alarmSystem is without distinguishing dissimilar fire detector, and can reach the object of power saving.
A kind of circuit driving method for fire alarm system is also proposed in another embodiment, wherein said circuitBe connected to one or more fire detectors, to provide electric energy to described fire detector, the method comprises: in normal workUnder state, provide the first electric current I to described circuitN1, wherein, described the first electric current IN1As the line under normal operating conditionsRoad monitor current; Detect the line voltage distribution V on described circuitLine; Judge described line voltage distribution VLineWhether lower than a thresholdValue Vth, wherein said threshold value VthSubnormal line voltage distribution but during higher than described fire detector alarm on described circuitThe maximum alarm voltage V indicatingAlarm; If judge described line voltage distribution VLineLower than described threshold value Vth, will be toThe electric current that described circuit provides is from described the first electric current IN1Switch to the second electric current IALARM, described the second electric current IALARMGreatlyIn described the first electric current IN1. Preferably, described the second electric current IALARMSize be enough to make described maximum alarm voltage VAlarmCan maintain a predetermined amount of time, to make described fire alarm system described alarm be detected.
Brief description of the drawings
Object of the present invention, feature, feature and advantage will become more apparent by the detailed description below in conjunction with accompanying drawing.Wherein:
Figure 1A shows the schematic structure of existing fire alarm system;
Figure 1B shows the connected mode of fire detector in the fire alarm system shown in Fig. 1;
Fig. 2 A and Fig. 2 B show respectively two kinds of fire detectors with different alarm modes;
Fig. 3 exemplarily shows the line drive circuit in fire alarm system according to an embodiment of the invention;
Fig. 4 exemplarily shows the line drive circuit in the fire alarm system of another embodiment according to the present invention;
The waveform schematic diagram of voltage and current when Fig. 5 shows and occurs alarm on circuit on circuit;
Fig. 6 exemplarily shows the schematic diagram of line drive circuit in accordance with another embodiment of the present invention.
Fig. 7 exemplarily shows according to an embodiment of the invention the flow process for the circuit driving method of fire alarm systemFigure.
Detailed description of the invention
Fire alarm system needs the fire detector of two types shown in compatible Fig. 2 A and Fig. 2 B, but this fire alarm of two typesThe alarm voltage difference (being for example respectively 5.6V and 12V) of detector, and for the fire detector shown in Fig. 2 B alsoNeed larger electric current to maintain its alarm status, otherwise this fire detector will be reset mistakenly automatically. Given this, thisBright inventor has proposed to provide different circuits to drive at circuit monitor stages and alert phrase respectively in following embodimentThe conception of streaming current. Particularly, at circuit monitor stages, whether normally carry out monitoring circuit with lower electric current, and findingWhen alarm, maintain alarm signal with higher electric current effective, in order to avoid fire detector mistake is reset. This conception can be simultaneouslySupport the fire detector of two types, and recognition detector type in advance. And this conception is also by realizingThe little electric current of monitor stages is powered, and reaches the object of power saving.
Fig. 3 shows according to an embodiment of the invention for the line drive circuit 300 of fire alarm system and via circuitLine is connected to fire detector 120 and the EOL of this drive circuit 300. As shown in Figure 3, drive circuit 300 is to circuitLine provides line current ILine. Fire detector 120 is connected between circuit Line+ and Line-. The far-end termination of circuitHave termination components EOL, termination components EOL is for example resistance element or is preferably Transient Voltage Suppressor (TVS). Due toThe existence of circuit (or cable) internal resistance (Rcable), the line current I of current through line LineLineSending to fire detectorBefore 120, form on the line certain pressure drop VR=ILine* Rcable. Thereby the voltage at fire detector 120 two ends is Vd=VLine-VR, wherein VLineFor the line voltage distribution of drive circuit 300 sides observations. The electric current of fire detector 120 of flowing through isId. The electric current of termination components EOL of far-end of flowing through is IEOL。
In the example shown in Fig. 3, drive circuit 300 comprises current generating circuit 310 and testing circuit 320. Electric current producesRaw circuit 310 can optionally provide at least two line current I that vary in size to circuit LineLine, i.e. the first electric currentIN1With the second electric current IALARMOne of in the two. Wherein, the first electric current IN1As the circuit monitoring electricity under normal operating conditionsStream, the second electric current IALARMAlarm electric current during as alarm, the second electric current IALARMBe greater than the first electric current IN1. Detect electricityRoad 320 is connected on circuit, for the line voltage distribution V detecting on circuit LineLineWhether lower than a threshold value VthWhen (that is, representing to have occurred alarm signal on circuit), control current generating circuit 310 to circuit Line through controlling path C1The second electric current I is providedALARM. Wherein, threshold value VthCan be set as lower than the normal voltage on circuit and higher than fire detectionThe maximum alarm voltage V indicating on circuit Line when device 120 alarmAlarm. Suppose, be connected to the fire detection of circuitDevice comprises two kinds of detector 120-1 and 120-2, V as shown in Figure 2 A and 2 BthCan be set as being greater than for example 12V,Be the alarm voltage of fire detector 120-2.
In example shown in Fig. 3, testing circuit 320 can specifically comprise two parts, and one is threshold decision circuit 321,It two is control circuit 325. Threshold decision circuit 321 is coupled on circuit, for judging line voltage distribution VLineWhether lower thanThreshold value Vth(for example 12V). Control circuit 325 is at line voltage distribution VLineBe reduced to threshold value VthUnder time, make electric current produceRaw circuit 310 is from providing the first electric current IN1Be switched to the second electric current I is providedALARM. Like this, in normal condition, adopt littleElectric current IN1Monitor, at alarm status, adopt large electric current IALARMMaintain alarm signal. Thus, not only can supportDissimilar fire detector can also be central control system power saving.
Fig. 4 illustrates drive circuit 400 in accordance with another embodiment of the present invention. In example as shown in Figure 4, electric current producesCircuit 410 is preferably for example two current sources in parallel, and the outgoing route of one of them current source is provided with a gate-controlled switchK. Under normal condition, gate-controlled switch K disconnects, and only the first current source provides monitor current I to circuit LineN1. In inspectionSlowdown monitoring circuit 420 monitors VLineDrop to VthBelow, while there is alarm ALARM, testing circuit 420 gauge tapsK conducting, thereby current source IN1With current source IALProvide electric current I to circuit Line simultaneouslyALARM=IN1+IAL。
In example shown in Fig. 4, testing circuit 420 comprises a series arm as threshold decision, and this series arm connectsBe connected between circuit Line+ and Line-. This series arm comprises a Zener diode D1 and a resistance R 3. Detect electricityRoad 420 is output as the voltage Vt of tie point between Zener diode D1 and resistance R 3. Wherein, Zener diode is anti-Be threshold voltage V to breakdown voltageth, for example, be greater than the maximum alarm voltage 12V of fire detector for 15V(). Certainly,In the example shown in Fig. 4, Zener diode D1 can also be substituted by two or more Zener diode, thisTime these Zener diodes breakdown reverse voltage sum be described threshold voltage Vth. In the example shown in Fig. 4, justNormal work (VLine=24V) time due to Zener diode D1 reverse breakdown, Vt is high level; There is alarm (VLine<15V)Time Zener diode D1 be high-impedance state, Vt is low level. In the example shown in Fig. 4, control circuit is reduced to directlyCome conducting or the disconnection of gauge tap K via control path C1 with the voltage of Vt. Shown in Fig. 4 is a kind of simple realExisting method. According to actual needs, those skilled in the art also can adopt comparator to realize the threshold decision circuit in Fig. 3321, and control circuit 325 can rationally convert the output of for example this comparator after gauge tap K again. These distortionAll apparent to those skilled in the art.
Fig. 5 shows shown in Fig. 4 the oscillogram of the electric current on circuit and voltage in example. As shown in Figure 5, normally(NORM) under duty, drive circuit 400 output monitoring electric current IN1Upper to circuit Line, line voltage distribution VLineRemain on for example normal voltage VN=24V. In the time of some or multiple fire detector alarm, line voltage distribution VLine is littleDrawnLow to such as Vth=15V of Vth() below, be for example pulled down to VAL=12V or 5.6V. Now, drive circuit 400 is defeatedGo out IALARM=IN1+IAL, to make alarm voltage VALMaintain a period of time Ta. Then, fire detector is reset automaticallyAnd enter the normal monitor procedure in next cycle. I in the example shown in Fig. 5N1For example be about 6mA, IALAbout 24mA,IALARM=IN1+IAL=about 30mA. But, choose reasonable I as required in actual applicationsN1And IALSize.Below only exemplarily list the mode of selection.
In example shown in Fig. 3 and Fig. 4, preferably, IN1Need to be greater than that (monitor stages flows through the quiet of all fire detectorsState electric current sum+the flow through minimum forward current of termination components EOL). If suppose that the quiescent current of each detector is Im,M=0,1, ~, M, wherein M is the maximum number of attachable detector on circuit, IN1Can meet following formula:
IN1≥（M×Max(Im)+Min(IEOL)）,
Wherein, Max (Im) represents the maximum of each detector quiescent current, Min (IEOL) represent to flow through the minimum forward electricity of EOLFlow valuve. Preferably, IN1For about 6mA or lower.
In the example shown in Fig. 3 and Fig. 4, preferably, IALARMNeed to provide large electric current, to make as shown in Figure 2 BThe alarm voltage of fire detector can maintain for example 12V. For example,, for the structure shown in Fig. 2 B, IALARMFor greatlyWhen about 30mA, alarm voltage can maintain and be greater than 12V, is so just enough to avoid detector automatically to be reset. Certainly ability,Field technique personnel are choose reasonable I according to actual needsALARMSize.
Fig. 6 exemplarily shows a kind of particular circuit configurations of block diagram shown in Fig. 3. As shown in Figure 6, drive circuit 600Comprise current generating circuit 610 and testing circuit 620.
Current generating circuit 610 is preferably a current source that output current is variable. This current source comprises that is operated in an amplificationUnder state and connect into common emitter circuit triode V101, be connected on the variable resistance circuit of the emitter-base bandgap grading of this triode V101612, for controlling the voltage control circuit 613 of these variable resistance circuit 612 both end voltage.
As shown in Figure 6, the triode V101 in current source is for example positive-negative-positive triode, its colelctor electrode C as output stage,Be connected on circuit Line. The emitter-base bandgap grading E of triode V101 is also connected to Vcc through variable resistance circuit 612. Although Fig. 6Show the scheme that realizes current source with positive-negative-positive triode, but it will be appreciated by those skilled in the art that this current source also canWith by NPN type triode, metal-oxide-semiconductor, amplifier etc. other circuit that can be used for building current source realize.
In Fig. 6, and Vcc obtains a stable ginseng at a R place after series resistance R118, R114 and R119 dividing potential dropExamine voltage Vref. Voltage-stabiliser tube 614 is for the voltage at stable series connection resistance R 118 and R114 two ends. Voltage control circuit 613Obtain sampled voltage from the emitter-base bandgap grading E of triode, and it is compared with reference voltage Vref, comparative result is preferably long-pending through ratioAfter point (PI), for controlling the base stage B of triode V101, adjust thus VCESize. Like this, variable resistor electricityThe voltage at 612 two ends, road can be issued to substantially invariable size in the control of voltage control circuit 613. In other words, triodeThe size of current of V101 output is determined by the resistance sizes of variable resistance circuit 612 of the emitter-base bandgap grading E that is connected on V101.
In the example shown in Fig. 6, variable resistance circuit 612 comprises two the resistance branch R108 and the R111 that are connected in parallel to each other.In the resistance branch at R111 place, be also provided with a controlled switch element K, the controlled end of K is connected to testing circuit 620Output. In the example shown in Fig. 6, controlled switch element K is preferably a metal-oxide-semiconductor V102, its grid GFor controlled end. When grid voltage while being high metal-oxide-semiconductor V102 disconnect, thereby only resistance R 108 is worked, triode V101Output current size is IN1=VR108/ R108. When grid voltage metal-oxide-semiconductor V102 conducting while being low, thus resistance R 111With resistance R 108 parallel connections, triode V101 output current size IALARM=VR108/（R108//R111）。
Although Fig. 6 shows the solution of carrying out regulation output electric current with variable emitter resistance, those skilled in the artBe understandable that, current generating circuit 610 can also adopt other modes that two kinds of driving of varying in size are optionally providedStreaming current. For example, current generating circuit 610 can also provide switchable output current by voltage source and variable resistance.Again for example, current generating circuit 610 can also be the electric current heavy (currentsink) for current drawn from circuit. Equally, for example this electric current is heavy can be made up of the triode that connects into common firing-circuit, and very output of the current collection of triode, penetratesThe utmost point is connected to ground via the second resistance. Voltage control circuit for the voltage stabilization that makes described the second resistance two ends theUpper one of in one magnitude of voltage and second voltage value, wherein, this voltage control circuit can be in response to described testing circuit (620)Control signal and the first magnitude of voltage is switched to second voltage value.
In the example shown in Fig. 6, testing circuit 620 comprises Zener diode V112 and the resistance R 121 of connecting with it,The two is connected between Line+ and Line-, as threshold decision circuit 621. The reverse breakdown of this Zener diode V112Voltage equals threshold value Vth, for example 15V. Alternatively, this Zener diode V112 also can be replaced by multiple Zener diodeIn generation, the breakdown reverse voltage sum of the plurality of Zener diode equals threshold value Vth. In addition, control circuit 625 is by voltage stabilizing twoThe voltage Vp of binding site P between utmost point pipe V112 and resistance R 121 is as threshold decision result.
At Fig. 6, control circuit 625 comprises the on-off circuit for Vp being converted to switching value, and this on-off circuit comprises cascadeTriode V109 and V107. Two triode V107 and V109 all connect into common emitter circuit, and wherein V109's is defeatedEnter for Vp, the output of V109 is as the input of V107. The output of V107 is for controlling opening of variable resistance circuit 612Close the controlled end of K. Thus, work as VLineDuring lower than Vth, Vp from high level become (GND), make originally conductingTriode V109 turn-off, and then VAlarm_LineBecome high level. At the V of this high levelAlarm_LineUnder driving, V107Conducting, thus the colelctor electrode C of V107 end becomes low level, and make thus metal-oxide-semiconductor V102 conducting, i.e. resistance R 111In parallel with R108. Can realize thus larger drive current is provided on the line in response to alarm signal, to maintain alarmVoltage.
Fig. 7 exemplarily shows according to an embodiment of the invention and drives for the circuit of example fire alarm system as shown in Figure 1BMoving method. Wherein, the fire detector being connected in circuit can comprise the detector as shown in Fig. 2 A and/or Fig. 2 B.As shown in Figure 7, circuit driving method is from step S710. In step S710, in normal operation, to lineRoad Line provides the first electric current IN1, wherein, the first electric current IN1As the circuit monitoring electric current under normal operating conditions. In stepIn rapid S720, the line voltage distribution V on detection line LineLine. In step S730, judge line voltage distribution VLineWhetherLower than a threshold value Vth, threshold value VthSubnormal line voltage distribution but indicate on the line during higher than fire detector alarmMaximum alarm voltage VAlarm. For example, VAlarmFor example, for the alarm voltage of the detector shown in Fig. 2 B, 12V, VthMay be selected to be for example 15V. If judged result is no, method flow returns to step S720 continuation detection line voltage VLine。If judged result is yes, show to occur alarm, and then method flow proceeds to step S740. In step S740,By the electric current providing to circuit Line from the first electric current IN1Switch to the second electric current IALARM. Wherein IALARM>IN1. PreferablyGround, the second electric current IALARMSize be enough to make described maximum alarm voltage VAlarmCan maintain a predetermined amount of time, withMake described fire alarm system described alarm be detected.
It will be appreciated by those skilled in the art that disclosed each embodiment can be in the situation that not departing from invention essence aboveMake various changes and amendment, within these changes and amendment all should drop on protection scope of the present invention. Therefore, the present inventionProtection domain should be limited by appending claims.
Claims (15)
1. for a drive circuit for fire alarm system, this drive circuit is for being provided to electric energy to be connected with one or more fireThe circuit (Line) of alert detector (120) is upper, and obtains signal from described circuit, and this drive circuit comprises:
Current generating circuit (310,410,610), it can optionally provide the first electric current to described circuit (Line)(IN1) and the second electric current (IALARMOne of) the two, wherein, under normal operating conditions, described current generating circuit providesDescribed the first electric current (IN1) for circuit monitoring, described the second electric current (IALARM) be greater than described the first electric current (IN1)；
Testing circuit (320,420,620), for detection of the line voltage distribution (V on described circuit (Line)Line) whetherLower than a threshold value (Vth), and at described line voltage distribution (VLine) during lower than described threshold value (Vth), control described electric currentProduce circuit (310,410,610) and provide the second electric current (I to described circuit (Line)ALARM), wherein said threshold value(Vth) subnormal line voltage distribution but indicate on described circuit during higher than described fire detector (120) alarmMaximum alarm voltage (VAlarm)。
2. drive circuit as claimed in claim 1, wherein, described the second electric current (IALARM) size make described inLarge alarm voltage (VAlarm) can maintain a predetermined amount of time, to make described fire alarm system described alarm voltage be detected(VAlarm)。
3. drive circuit as claimed in claim 1, wherein, when the distal end of described circuit (Line) is connected at least oneWhen termination components (EOL),
Described the first electric current (IN1) > (can be connected to maximum number × each fire detector of the fire detector of described circuitThe minimum forward current of quiescent current+described termination components (EOL)).
4. as the drive circuit as described in arbitrary in claim 1-3, wherein, described testing circuit (320,420,620)Comprise:
Threshold decision circuit (321), is connected to described circuit (Line) upper, for judge described line electricity with hardware modePress (VLine) whether lower than described threshold value (Vth)；
Control circuit (325), at described line voltage distribution (VLine) lower than described threshold value (Vth) time, control described electricityThe raw circuit of miscarriage (310), makes it from the first electric current (I is providedN1) be switched to the second electric current (I is providedALARM)。
5. drive circuit as claimed in claim 4, wherein, described threshold decision circuit comprises:
Series arm, described line voltage distribution (V is coupled at its two endsLine), this series arm comprises at least one Zener diode(D1, V112) and the first resistance (R3, R121), described at least one Zener diode (D1, V112) puncturesVoltage sum equals described threshold value (Vth); And
Described control circuit will connect between described the first resistance (R3, R121) and described Zener diode (D1, V112)The voltage of contact is as threshold decision result, for controlling described current generating circuit (310,410,610).
6. drive circuit as claimed in claim 5, wherein said control circuit (625) comprises for described threshold value is sentencedDisconnected results conversion is the on-off circuit of switching value.
7. as the drive circuit as described in arbitrary in claim 1-3, wherein said current generating circuit be current source (410,610)。
8. drive circuit as claimed in claim 7, wherein said current source (610) comprising:
Triode (V101), connects into common emitter circuit, for providing current to described circuit (Line);
Variable resistance circuit (612), it is connected on the emitter-base bandgap grading of described triode (V101), and its resistance sizes can be at leastBetween the first resistance value and the second resistance value, switch;
Voltage control circuit (613), for making the voltage stabilization at described variable resistance circuit (612) two ends predetermined at oneVoltage;
Wherein, described variable resistance circuit (612) switches in response to the control signal from described testing circuit (620)The size of its resistance value.
9. drive circuit as claimed in claim 8, wherein said variable resistance circuit (612) comprising:
At least two resistance branch (R108, R111) that are connected in parallel are provided with one in one of them resistance branchIndividual controlled switch (K), described controlled switch (K) is closed in response to the control signal of described testing circuit.
10. drive circuit as claimed in claim 7, wherein said current source comprises:
Triode, connects into common emitter circuit, for drawing the electric current on described circuit (Line), on its emitter-base bandgap grading, is connected withThe second resistance;
Voltage control circuit, for the voltage stabilization of controlling described the second resistance two ends in the first magnitude of voltage and second voltage valueOne of, wherein, described voltage control circuit in response to the control signal of described testing circuit (620) by the first magnitude of voltageSwitch to second voltage value.
11. 1 kinds of fire alarm systems, comprising:
One or more fire detectors (120), for surveying whether occur the condition of a fire in its region;
As the drive circuit as described in arbitrary in claim 1-10, be connected with one or more fire alarms and visit for electric energy is provided toSurvey on the circuit (Line) of device (120);
Termination components (EOL), is connected to the far-end of described circuit (Line), for circuit described in termination (Line).
12. fire alarm systems as claimed in claim 11, wherein fire detector (120) comprises that at least one is in the time of alarmNeed electric current to maintain the detector of its alarm voltage.
13. fire alarm systems as claimed in claim 12, wherein, described termination components (EOL) is Transient Suppression Diode(TVS)。
14. 1 kinds of circuit driving methods for fire alarm system, wherein said connection is to one or more fire detectors(120),, to provide electric energy to described fire detector, the method comprises:
In normal operation, provide the first electric current (I to described circuit (Line)N1), wherein, described the first electric current (IN1)As the circuit monitoring electric current under normal operating conditions;
Detect the line voltage distribution (V on described circuit (Line)Line)；
Judge described line voltage distribution (VLine) whether lower than a threshold value (Vth), wherein said threshold value (Vth) lower than normallyLine voltage distribution under duty but the maximum that indicates on described circuit during higher than described fire detector (120) alarmAlarm voltage (VAlarm)；
If judge described line voltage distribution (VLine) lower than described threshold value (Vth), will provide to described circuit (Line)Electric current from described the first electric current (IN1) switch to the second electric current (IALARM), described the second electric current (IALARM) be greater than described inThe first electric current (IN1)。
15. driving methods as claimed in claim 14, wherein, described the second electric current (IALARM) size be enough to make instituteState maximum alarm voltage (VAlarm) can maintain a predetermined amount of time, to make described fire alarm system described alarm be detected.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210270657.0A CN103578218B (en) | 2012-07-31 | 2012-07-31 | The line drive circuit of fire alarm system and corresponding fire alarm system |
| EP13172598.8A EP2693415A1 (en) | 2012-07-31 | 2013-06-19 | Line drive circuit for fire alarm system and corresponding fire alarm system |
| RU2013135767/08A RU2575415C2 (en) | 2012-07-31 | 2013-07-30 | Tire excitation circuit for fire alarm system and fire alarm system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210270657.0A CN103578218B (en) | 2012-07-31 | 2012-07-31 | The line drive circuit of fire alarm system and corresponding fire alarm system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103578218A CN103578218A (en) | 2014-02-12 |
| CN103578218B true CN103578218B (en) | 2016-05-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210270657.0A Active CN103578218B (en) | 2012-07-31 | 2012-07-31 | The line drive circuit of fire alarm system and corresponding fire alarm system |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP2693415A1 (en) |
| CN (1) | CN103578218B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2508033B (en) * | 2012-11-20 | 2016-02-17 | Sprue Safety Products Ltd | Low power detection and alarm |
| CN104897967B (en) * | 2014-03-04 | 2019-02-01 | 西门子瑞士有限公司 | The live line detection device and method of fire alarm system |
| JP6871096B2 (en) * | 2017-07-21 | 2021-05-12 | ホーチキ株式会社 | Tunnel disaster prevention system |
| CN108616792A (en) * | 2018-06-26 | 2018-10-02 | 宗仁科技(平潭)有限公司 | Imitate the integrated circuit and warning device of alarm song |
| CN113313922A (en) * | 2021-05-31 | 2021-08-27 | 陕西建工智能科技有限公司 | On-line monitoring device and method for line state of automatic fire alarm system in construction site |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1460281A (en) * | 1973-10-18 | 1976-12-31 | Electronic Alarms Ltd | Electrical circuits |
| US5670937A (en) * | 1995-05-16 | 1997-09-23 | General Signal Corporation | Line monitor for two wire data transmission |
| CN102176181A (en) * | 2011-01-17 | 2011-09-07 | 深圳市奥瑞那光子技术有限公司 | Constant flow source power supply circuit of point pattern photoelectric smoke detector |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4789318B2 (en) * | 2000-10-18 | 2011-10-12 | 矢崎総業株式会社 | Fire alarm device and gas fire detector |
| US7400227B2 (en) * | 2005-06-30 | 2008-07-15 | Ge Security, Inc. | Fire alarm notification power supply with configurable notification appliance circuits and auxiliary power circuits apparatus and method |
| DE102008028631B4 (en) * | 2008-06-18 | 2011-06-22 | GEZE GmbH, 71229 | Line monitoring of smoke switches |
-
2012
- 2012-07-31 CN CN201210270657.0A patent/CN103578218B/en active Active
-
2013
- 2013-06-19 EP EP13172598.8A patent/EP2693415A1/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1460281A (en) * | 1973-10-18 | 1976-12-31 | Electronic Alarms Ltd | Electrical circuits |
| US5670937A (en) * | 1995-05-16 | 1997-09-23 | General Signal Corporation | Line monitor for two wire data transmission |
| CN102176181A (en) * | 2011-01-17 | 2011-09-07 | 深圳市奥瑞那光子技术有限公司 | Constant flow source power supply circuit of point pattern photoelectric smoke detector |
Also Published As
| Publication number | Publication date |
|---|---|
| RU2013135767A (en) | 2015-02-10 |
| EP2693415A1 (en) | 2014-02-05 |
| CN103578218A (en) | 2014-02-12 |
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