CN103578218A - Circuit driving circuit of fire alarm system and corresponding fire alarm system - Google Patents
Circuit driving circuit of fire alarm system and corresponding fire alarm system Download PDFInfo
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- CN103578218A CN103578218A CN201210270657.0A CN201210270657A CN103578218A CN 103578218 A CN103578218 A CN 103578218A CN 201210270657 A CN201210270657 A CN 201210270657A CN 103578218 A CN103578218 A CN 103578218A
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- circuit
- line
- alarm
- voltage
- electric current
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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
Abstract
The invention provides a driving circuit and driving method for a fire alarm system. The driving circuit comprises a current generating circuit and a detection circuit, the current generating circuit can selectively provide a circuit with a first current IN1 or a second current IALARM, the first current IN1 is used as a circuit monitor current under a normal work station, and the second current IALARM is larger than the first current IN1. The detection circuit is used for controlling the current generating circuit to provide the circuit with the second current IALARM when a circuit voltage VLine on the circuit is detected to be lower than a threshold value Vth, and the threshold value Vth is lower than a normal circuit voltage and higher than the maximum alarm voltage indicated on the circuit when the fire alarm system gives an 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 method in a kind of fire alarm system.
Background technology
Automatic fire alarm system, is called for short fire alarm system, be people for early detection, the circular condition of a fire, and adopt an effective measure in time, as controlled and putting out the condition of a fire, and be arranged in buildings or other residing a kind of automatic fire-fighting facility.Current most of buildings, 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, fire alarm system 100 generally comprises central control system 110 and is connected to a plurality of fire detectors 120 of central control system 110 and/or a plurality of manual alarm 130 etc. by circuit Line.Fire detector 120 and manual alarm 130 all send alarm signal to central control system 110 via circuit Line.Central control system 110 takes in response to this alarm signal put out a fire accordingly measure and means of communication automatically.Thus, adopt the fire alarm system shown in Figure 1A can realize automatic alarm, self-extinguishing, safe escape induction, systematic procedure demonstration, fire archieves management etc., thereby form a complete fire control system.
In Figure 1A, fire detector 120 is instruments of detection of fires.Due to the stage occurring in the condition of a fire, will supervene smog, high temperature, flame etc.These cigarettes, light and heat can be by smoke detector 120(" S ") or hygrosensor 120(" H ") change electric signal into and report to the police and make central control system automatically start extinguishing device, fire extinguishing in time.Central control system 110 provides driving to each fire detector 120 or manual alarm 130 via circuit Line, so that it obtains enough electric energy, to work.Meanwhile, whether central control system 110 also periodic Monitoring Line Line occurs opening circuit or short trouble, to guarantee the normal operation of fire detector 120 and manual alarm 130.
Figure 1B has specifically illustrated for example annexation of fire detector 120 and central control system 110.In the example shown in Figure 1B, a plurality of fire detectors 120 are connected in parallel between circuit Line+ and Line-, and are connected to termination components (EOL:End of Line) in the distal end of circuit Line.Here termination components EOL can be resistance element, for detection of circuit, whether has fault.Particularly, when opening circuit appears in circuit Line, the line resistance detecting from central control system 110 sides is by the resistance higher than EOL; When short circuit appears in circuit, the line resistance detecting from central control system 110 sides will be less than the resistance of EOL.Thus, whether EOL can contribute to detection line normal.
Fig. 2 B shows the another kind of alarm mode of fire detector 120-2.As shown in Figure 2 B, actuating switch K2 when its sensing module 220 detects the condition of a fire, this K switch 2 and a small resistor (for example 450ohm) are connected between circuit Line+ and Line-.Like this, for example 30mA electric current during K switch 2 conducting on circuit can pour into small resistor, and makes thus line voltage distribution be 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 reset mechanism (RESET) mistakenly, and causes missing current alarm.
In existing central control system, general respectively for the different fire detector design driven circuit shown in Fig. 2 A and Fig. 2 B, and identify in advance the type that connected fire detector is Fig. 2 A by wire jumper or software recognition method, 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-mentioned wrong generation of resetting.But, consider the requirement of 110 pairs of power savings of central control system, 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 driving circuit in a kind of fire alarm system, and this driving circuit is for driving the circuit that is connected with one or more fire detectors.Adopt this driving circuit can support adaptively the fire detector of two types shown in Fig. 2 A and Fig. 2 B, but also can reach the object of power saving.A kind of driving circuit of fire alarm system has been proposed in one embodiment of the invention.This driving circuit is for being provided to by electric energy the circuit that is connected with one or more fire detectors, and this driving circuit comprises: current generating circuit, it can optionally provide the first electric current I to described circuit
n1with the second electric current I
aLARMone of the two, wherein, described the first electric current I
n1as the circuit monitoring electric current under normal operating conditions, described the second electric current I
aLARMbe greater than described the first electric current I
n1; Whether testing circuit,, and, control described current generating circuit and provide the second electric current I to described circuit Line during lower than described threshold value Vth at described line voltage distribution lower than a threshold value for detection of the line voltage distribution on described circuit
aLARM, wherein said threshold value V
thsubnormal line voltage distribution but the maximum alarm voltage V that indicates on described circuit during higher than described fire detector alarm
alarm.Preferably, described the second electric current I
aLARMsize make described maximum alarm voltage V
alarmcan maintain a predetermined amount of time, so that described fire alarm system detects described alarm voltage V
alarm.More preferably, when the distal end of described circuit Line is connected at least one termination components (EOL), described the first electric current I
n1> (can be connected to the minimum forward current of the quiescent current+described termination components EOL of maximum number * each fire detector of the fire detector of described circuit).
Above-mentioned driving circuit can provide little monitor current I at monitor stages
n1, and provide larger alarm electric current I in the alert phrase
aLARM.Can, so that fire alarm system detects the alarm signal of dissimilar fire detector, can also reduce to a certain extent the energy consumption of fire alarm system simultaneously like this.Due to the more efficiently power saving of this driving circuit, therefore correspondingly the accumulator of fire alarm system is maintained the longer working time.
In one embodiment of the invention, described testing circuit comprises: threshold decision circuit, is connected to described circuit Line upper, for judge described line voltage distribution V with hardware mode
linewhether lower than described threshold value V
th; Control circuit, at described line voltage distribution V
linelower than described threshold value V
thtime, control described current generating circuit, make it from the first electric current I is provided
n1be switched to the second electric current I is provided
aLARM.Because above-mentioned driving circuit adopts hardware detecting circuit, realize threshold decision and FEEDBACK CONTROL, so this driving circuit can detect alarm signal within the extremely short time, and larger alarm electric current I is provided immediately
aLARMmaintain 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, described line voltage distribution V is coupled at its two ends
line, this series arm comprises at least one voltage stabilizing diode and the first resistance, the breakdown reverse voltage sum of described at least one voltage stabilizing diode equals described threshold value V
th; And the voltage of described control circuit tie point between described the first resistance and described voltage stabilizing diode is as threshold decision result, for controlling described current generating circuit.Preferably, described control circuit comprises for the on-off circuit that is switching value by described threshold decision results conversion.Adopt in this embodiment simple voltage stabilizing 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 current 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 switched between the first resistance value and the second resistance value; 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 variable resistance circuit comprises: at least two resistance branch that are connected in parallel, in one of them resistance branch, be provided with a controlled switch, and 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, connect into common emitter circuit, and for drawing the electric current on described circuit Line, on its emitter-base bandgap grading, be connected with the second resistance; Voltage control circuit, for the voltage stabilization of controlling described the second resistance two ends, in one of the first magnitude of voltage and second voltage value, wherein, described voltage control circuit switches to second voltage value in response to the control signal of described testing circuit by the first magnitude of voltage.
A kind of fire alarm system has also been proposed in another embodiment.This fire alarm system comprises: one or more fire detectors, for surveying whether occur the condition of a fire in its region; Driving circuit as above, for being provided to electric energy in the circuit that is connected with one or more fire detectors; Termination components (EOL), is connected to the far-end of described circuit, for circuit described in termination.Preferably, described termination components (EOL) is transient state voltage stabilizing diode (TVS).Preferably, fire detector comprises that at least one needs extra current to maintain the detector of its alarm voltage when alarm.Adopt this fire alarm system without distinguishing dissimilar fire detector, and can reach the object of power saving.
A kind of circuit driving method for fire alarm system has also been proposed in another embodiment, wherein said connection is to one or more fire detectors, to provide electric energy to described fire detector, the method comprises: in normal operation, to described circuit, provide the first electric current I
n1, wherein, described the first electric current I
n1as the circuit monitoring electric current under normal operating conditions; Detect the line voltage distribution V on described circuit
line; Judge described line voltage distribution V
linewhether lower than a threshold value V
th, wherein said threshold value V
thsubnormal line voltage distribution but the maximum alarm voltage V that indicates on described circuit during higher than described fire detector alarm
alarm; If judge described line voltage distribution V
linelower than described threshold value V
th, by the electric current providing to described circuit from described the first electric current I
n1switch to the second electric current I
aLARM, described the second electric current I
aLARMbe greater than described the first electric current I
n1.Preferably, described the second electric current I
aLARMsize be enough to make described maximum alarm voltage V
alarmcan maintain a predetermined amount of time, so that described fire alarm system detects described alarm.
Accompanying drawing explanation
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 process flow diagram for the circuit driving method of fire alarm system.
Embodiment
Fire alarm system needs the fire detector of two types shown in compatible Fig. 2 A and Fig. 2 B, but the alarm voltage of this fire detector of two types different (being for example respectively 5.6V and 12V), and also need larger electric current to maintain its alarm status for the fire detector shown in Fig. 2 B, otherwise this fire detector will be reset mistakenly automatically.Given this, the present inventor has proposed respectively to provide in circuit monitor stages and alert phrase the conception of different circuit drive current in following embodiment.Particularly, at circuit monitor stages, with lower electric current, come monitoring circuit whether normal, and it is effective when finding alarm, with higher electric current, to maintain alarm signal, in order to avoid fire detector mistake is reset.This conception can be supported the fire detector of two types simultaneously, and recognition detector type in advance.And this conception is also powered at the little electric current of monitor stages by realizing, 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 fire detector 120 and the EOL that is connected to this driving circuit 300 via circuit Line.As shown in Figure 3, driving circuit 300 provides line current I to circuit Line
line.Fire detector 120 is connected between circuit Line+ and Line-.The distal end of circuit is connected to termination components EOL, and termination components EOL is for example resistance element or is preferably Transient Voltage Suppressor (TVS).Due to the existence of circuit (or cable) internal resistance (Rcable), the line current I of current through line Line
linebefore sending to fire detector 120, form on the line certain pressure drop V
r=I
line* Rcable.Thereby the voltage at fire detector 120 two ends is Vd=V
line-V
r, V wherein
lineline voltage distribution for driving circuit 300 sides observations.The electric current of fire detector 120 of flowing through is Id.The electric current of termination components EOL of far-end of flowing through is I
eOL.
In the example shown in Fig. 3, driving circuit 300 comprises current generating circuit 310 and testing circuit 320.Current generating circuit 310 can optionally provide at least two line current I that vary in size to circuit Line
line, i.e. the first electric current I
n1with the second electric current I
aLARMone of in the two.Wherein, the first electric current I
n1as the circuit monitoring electric current under normal operating conditions, the second electric current I
aLARMalarm electric current during as alarm, the second electric current I
aLARMbe greater than the first electric current I
n1.Testing circuit 320 is connected on circuit, for the line voltage distribution V detecting on circuit Line
linewhether lower than a threshold value V
thwhen (that is, representing to have occurred alarm signal on circuit), through controlling path C1 control current generating circuit 310, to circuit Line, provide the second electric current I
aLARM.Wherein, threshold value V
ththe maximum alarm voltage V indicating on circuit Line in the time of can being set as lower than the normal voltage on circuit and higher than fire detector 120 alarm
alarm.Suppose, the fire detector that is connected to circuit comprises two kinds of detector 120-1 and 120-2, V as shown in Figure 2 A and 2 B
thcan be set as being greater than for example 12V, i.e. 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, and it two is control circuit 325.Threshold decision circuit 321 is coupled on circuit, for judging line voltage distribution V
linewhether lower than threshold value V
th(for example 12V).Control circuit 325 is at line voltage distribution V
linebe reduced to threshold value V
thunder time, make current generating circuit 310 from the first electric current I is provided
n1be switched to the second electric current I is provided
aLARM.Like this, in normal condition, adopt little electric current I
n1monitor, at alarm status, adopt large electric current I
aLARMmaintain alarm signal.Thus, not only can support dissimilar fire detector, can also be central control system power saving.
Fig. 4 illustrates driving circuit 400 in accordance with another embodiment of the present invention.In example as shown in Figure 4, current generating circuit 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 switch K.Under normal condition, gate-controlled switch K disconnects, and only the first current source provides monitor current I to circuit Line
n1.At testing circuit 420, monitor V
linedrop to V
thbelow, while there is alarm ALARM, testing circuit 420 gauge tap K conductings, thereby current source I
n1with current source I
aLto circuit Line, provide electric current I simultaneously
aLARM=I
n1+ I
aL.
In example shown in Fig. 4, testing circuit 420 comprises that one as the series arm of threshold decision, and this series arm is connected between circuit Line+ and Line-.This series arm comprises a voltage stabilizing diode D1 and a resistance R 3.Testing circuit 420 is output as the voltage Vt of tie point between voltage stabilizing diode D1 and resistance R 3.Wherein, the breakdown reverse voltage of voltage stabilizing diode is threshold voltage V
th, for example, for 15V(, be greater than the maximum alarm voltage 12V of fire detector).Certainly, in the example shown in Fig. 4, voltage stabilizing diode D1 can also be substituted by two or more voltage stabilizing diode, and at this moment the breakdown reverse voltage sum of these voltage stabilizing diodes is described threshold voltage V
th.In the example shown in Fig. 4, at normal operation (V
line=24V) time, due to voltage stabilizing diode D1 reverse breakdown, Vt is high level; There is alarm (V
line<15V) time, voltage stabilizing diode D1 is high-impedance state, and Vt is low level.In the example shown in Fig. 4, control circuit is reduced to the direct voltage with Vt and via control path C1, comes conducting or the disconnection of gauge tap K.Shown in Fig. 4 is a kind of simple implementation method.According to actual needs, those skilled in the art also can adopt comparer to realize the threshold decision circuit 321 in Fig. 3, and control circuit 325 can rationally convert the output of for example this comparer after gauge tap K again.These distortion are all 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, under normal (NORM) duty, driving circuit 400 output monitoring electric current I
n1upper to circuit Line, line voltage distribution V
lineremain on for example normal voltage V
n=24V.When some or a plurality of fire detector alarm, line voltage distribution V
line is littlebe pulled down to for example Vth=15V of Vth() below, be for example pulled down to V
aL=12V or 5.6V.Now, driving circuit 400 output I
aLARM=I
n1+ I
aL, so that alarm voltage V
aLmaintain a period of time Ta.Then, fire detector is automatically reset and is entered the normal monitor procedure in next cycle.I in the example shown in Fig. 5
n1for example be about 6mA, I
aLabout 24mA, I
aLARM=I
n1+ I
aL=about 30mA.But, choose reasonable I as required in actual applications
n1and I
aLsize.Below only exemplarily list the mode of selection.
In example shown in Fig. 3 and Fig. 4, preferably, I
n1need to be greater than (monitor stages flows through the quiescent current sum of all fire detectors+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, I
n1can meet following formula:
I
N1≥（M×Max(Im)+Min(I
EOL)）,
Wherein, Max (Im) represents the maximal value of each detector quiescent current, Min (I
eOL) represent to flow through the minimum forward current value of EOL.Preferably, I
n1for about 6mA or lower.
In the example shown in Fig. 3 and Fig. 4, preferably, I
aLARMthe alarm voltage of fire detector as shown in Figure 2 B need to provide large electric current, so that can maintain for example 12V.For example,, for the structure shown in Fig. 2 B, I
aLARMduring for about 30mA, alarm voltage can maintain and be greater than 12V, is so just enough to avoid detector automatically to be reset.Certainly, those skilled in the art choose reasonable I according to actual needs
aLARMsize.
Fig. 6 exemplarily shows a kind of particular circuit configurations of block diagram shown in Fig. 3.As shown in Figure 6, driving circuit 600 comprises current generating circuit 610 and testing circuit 620.
As shown in Figure 6, the triode V101 in current source is for example positive-negative-positive triode, its collector 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. 6 shows the scheme that realizes current source with positive-negative-positive triode, it will be appreciated by those skilled in the art that this current source also can be 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 reference voltage Vref at a R place after resistance in series R118, R114 and R119 dividing potential drop.Stabilivolt 614 is for the voltage at stable series connection resistance R 118 and R114 two ends.Voltage control circuit 613 obtains sampled voltage from the emitter-base bandgap grading E of triode, and it is compared with reference voltage Vref, comparative result preferably after proportional integral (PI) for controlling the base stage B of triode V101, adjust thus V
cEsize.Like this, the voltage at variable resistance circuit 612 two ends can be issued in the control of voltage control circuit 613 substantially invariable size.In other words, the size of current of triode V101 output is determined by the resistance sizes of variable resistance circuit 612 that is connected on the emitter-base bandgap grading E of V101.
In the example shown in Fig. 6, variable resistance circuit 612 comprises two resistance branch R108 and the R111 being 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 the output terminal of testing circuit 620.In the example shown in Fig. 6, controlled switch element K is preferably a metal-oxide-semiconductor V102, and its grid G is controlled end.When grid voltage while being high metal-oxide-semiconductor V102 disconnect, thereby only resistance R 108 work, triode V101 output current size is I
n1=V
r108/ R108.When grid voltage metal-oxide-semiconductor V102 conducting while being low, thus resistance R 111 and resistance R 108 parallel connections, triode V101 output current size I
aLARM=V
r108/ (R108//R111).
Although Fig. 6 shows the solution of carrying out regulation output electric current with variable emitter resistance, it will be appreciated by persons skilled in the art that current generating circuit 610 can also adopt other modes that two kinds of drive currents that vary in size are optionally provided.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 (current sink) for current drawn from circuit.Same, for example this electric current is heavy can consist of the triode that connects into common firing-circuit, and the current collection of triode is output terminal very, and emitter-base bandgap grading is connected to ground via the second resistance.A voltage control circuit is for making the voltage stabilization at described the second resistance two ends in one of the first magnitude of voltage and second voltage value, wherein, this voltage control circuit can switch to second voltage value by the first magnitude of voltage in response to the control signal of described testing circuit (620).
In the example shown in Fig. 6, testing circuit 620 comprises voltage stabilizing diode V112 and the resistance R 121 of connecting with it, and the two is connected between Line+ and Line-, as threshold decision circuit 621.The breakdown reverse voltage of this voltage stabilizing diode V112 equals threshold value V
th, 15V for example.Alternatively, this voltage stabilizing diode V112 also can be substituted by a plurality of voltage stabilizing diode, and the breakdown reverse voltage sum of the plurality of voltage stabilizing diode equals threshold value Vth.In addition, the voltage Vp of the binding site P of control circuit 625 between voltage stabilizing diode V112 and resistance R 121 is as threshold decision result.
At Fig. 6, control circuit 625 comprises that this on-off circuit comprises triode V109 and the V107 of cascade for Vp being converted to the on-off circuit of switching value.Two triode V107 and V109 all connect into common emitter circuit, wherein V109 be input as Vp, the output of V109 is as the input of V107.The output of V107 is for controlling the controlled end of the K switch of variable resistance circuit 612.Thus, work as V
lineduring lower than Vth, Vp from high level become (GND), the triode V109 of originally conducting is turn-offed, and then V
alarm_Linebecome high level.V at this high level
alarm_Lineunder driving, V107 conducting, thus the collector C of V107 end becomes low level, and make thus metal-oxide-semiconductor V102 conducting, resistance R 111 is in parallel with R108.Can realize thus larger drive current is provided on the line in response to alarm signal, to maintain alarm voltage.
Fig. 7 exemplarily shows according to an embodiment of the invention the circuit driving method for example fire alarm system as shown in Figure 1B.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 circuit Line, provide the first electric current I
n1, wherein, the first electric current I
n1as the circuit monitoring electric current under normal operating conditions.In step S720, the line voltage distribution V on detection line Line
line.In step S730, judgement line voltage distribution V
linewhether lower than a threshold value V
th, threshold value V
thsubnormal line voltage distribution but the maximum alarm voltage V that indicates on the line during higher than fire detector alarm
alarm.For example, V
alarmfor the alarm voltage of the detector shown in Fig. 2 B, 12V for example, Vth may be selected to be for example 15V.If the determination result is NO, method flow returns to step S720 continuation detection line voltage V
line.If judgment result is that to be, 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 I
n1switch to the second electric current I
aLARM.I wherein
aLARM>I
n1.Preferably, the second electric current I
aLARMsize be enough to make described maximum alarm voltage V
alarmcan maintain a predetermined amount of time, so that described fire alarm system detects described alarm.
These changes and modification it will be appreciated by those skilled in the art that disclosed each embodiment can make various changes and modification in the situation that not departing from invention essence above, within all should drop on protection scope of the present invention.Therefore, protection scope of the present invention should be limited by appending claims.
Claims (15)
1. for a driving circuit for fire alarm system, this driving circuit is used for electric energy to be provided to the circuit (Line) that is connected with one or more fire detectors (120), and obtains signal from described circuit, and this driving circuit comprises:
Current generating circuit (310,410,610), it can optionally provide the first electric current (I to described circuit (Line)
n1) and the second electric current (I
aLARMone of) the two, wherein, under normal operating conditions, described current generating circuit provides described the first electric current (I
n1) for circuit monitoring, described the second electric current (I
aLARM) be greater than described the first electric current (I
n1);
Testing circuit (320,420,620), for detection of the line voltage distribution (V on described circuit (Line)
line) whether lower than a threshold value (V
th), and at described line voltage distribution (V
line) during lower than described threshold value (Vth), control described current generating circuit (310,410,610) and provide the second electric current (I to described circuit (Line)
aLARM), wherein said threshold value (V
th) subnormal line voltage distribution but the maximum alarm voltage (V that indicates on described circuit during higher than described fire detector (120) alarm
alarm).
2. driving circuit as claimed in claim 1, wherein, described the second electric current (I
aLARM) size make described maximum alarm voltage (V
alarm) can maintain a predetermined amount of time, so that described fire alarm system detects described alarm voltage (V
alarm).
3. driving circuit as claimed in claim 1, wherein, when the distal end of described circuit (Line) is connected at least one termination components (EOL),
Described the first electric current (I
n1) > (can be connected to the minimum forward current of the quiescent current+described termination components (EOL) of maximum number * each fire detector of the fire detector of described circuit).
4. as the driving circuit as described in arbitrary in claim 1-3, wherein, described testing circuit (320,420,620) comprising:
Threshold decision circuit (321), is connected to described circuit (Line) upper, for judge described line voltage distribution (V with hardware mode
line) whether lower than described threshold value (V
th);
Control circuit (325), at described line voltage distribution (V
line) lower than described threshold value (V
th) time, control described current generating circuit (310), make it from the first electric current (I is provided
n1) be switched to the second electric current (I is provided
aLARM).
5. driving circuit as claimed in claim 4, wherein, described threshold decision circuit comprises:
Series arm, described line voltage distribution (V is coupled at its two ends
line), this series arm comprises at least one voltage stabilizing diode (D1, V112) and the first resistance (R3, R121), the voltage breakdown sum of described at least one voltage stabilizing diode (D1, V112) equals described threshold value (V
th); And
The voltage of described control circuit tie point between described the first resistance (R3, R121) and described voltage stabilizing diode (D1, V112) is as threshold decision result, for controlling described current generating circuit (310,410,610).
6. driving circuit as claimed in claim 5, wherein said control circuit (625) comprises for the on-off circuit that is switching value by described threshold decision results conversion.
7. as the driving circuit as described in arbitrary in claim 1-3, wherein said current generating circuit is current source (410,610).
8. driving 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 at least be switched between the first resistance value and the second resistance value;
Voltage control circuit (613), for making the voltage stabilization at described variable resistance circuit (612) two ends at a predetermined voltage;
Wherein, described variable resistance circuit (612) switches the size of its resistance value in response to the control signal from described testing circuit (620).
9. driving 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 a controlled switch (K) in one of them resistance branch, and described controlled switch (K) is closed in response to the control signal of described testing circuit.
10. driving 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), is connected with the second resistance on its emitter-base bandgap grading;
Voltage control circuit, the voltage stabilization that is used for controlling described the second resistance two ends is in one of the first magnitude of voltage and second voltage value, wherein, described voltage control circuit switches to second voltage value in response to the control signal of described testing circuit (620) by the first magnitude of voltage.
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 driving circuit as described in arbitrary in claim 1-10, for electric energy being provided to the circuit (Line) that is connected with one or more fire detectors (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 needs electric current to maintain the detector of its alarm voltage when alarm.
13. driving methods 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), and to provide electric energy to described fire detector, the method comprises:
In normal operation, to described circuit (Line), provide the first electric current (I
n1), wherein, described the first electric current (I
n1) 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 (V
line) whether lower than a threshold value (V
th), wherein said threshold value (V
th) the maximum alarm voltage (V that indicates on described circuit during lower than the line voltage distribution under normal operating conditions but higher than described fire detector (120) alarm
alarm);
If judge described line voltage distribution (V
line) lower than described threshold value (V
th), the electric current that will provide to described circuit (Line) is from described the first electric current (I
n1) switch to the second electric current (I
aLARM), described the second electric current (I
aLARM) be greater than described the first electric current (I
n1).
15. driving methods as claimed in claim 14, wherein, described the second electric current (I
aLARM) size be enough to make described maximum alarm voltage (V
alarm) can maintain a predetermined amount of time, so that described fire alarm system detects described alarm.
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 true CN103578218A (en) | 2014-02-12 |
| CN103578218B CN103578218B (en) | 2016-05-18 |
Family
ID=48745640
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) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104897967A (en) * | 2014-03-04 | 2015-09-09 | 西门子瑞士有限公司 | Field wire detecting device and method for fire alarm 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 |
Families Citing this family (2)
| 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 |
| JP6871096B2 (en) * | 2017-07-21 | 2021-05-12 | ホーチキ株式会社 | Tunnel disaster prevention system |
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| 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 |
| JP2002133545A (en) * | 2000-10-18 | 2002-05-10 | Yazaki Corp | Fire alarm device and gas fire sensor |
| US20070001819A1 (en) * | 2005-06-30 | 2007-01-04 | Becker Donald E | Fire alarm notification power supply with configurable notification appliance circuits and auxiliary power circuits apparatus and method |
| 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 |
|---|---|---|---|---|
| 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 (5)
| 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 |
| JP2002133545A (en) * | 2000-10-18 | 2002-05-10 | Yazaki Corp | Fire alarm device and gas fire sensor |
| US20070001819A1 (en) * | 2005-06-30 | 2007-01-04 | Becker Donald E | Fire alarm notification power supply with configurable notification appliance circuits and auxiliary power circuits apparatus and method |
| 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 |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104897967A (en) * | 2014-03-04 | 2015-09-09 | 西门子瑞士有限公司 | Field wire detecting device and method for fire alarm 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 |
Also Published As
| Publication number | Publication date |
|---|---|
| RU2013135767A (en) | 2015-02-10 |
| CN103578218B (en) | 2016-05-18 |
| EP2693415A1 (en) | 2014-02-05 |
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