JP2010257213A - Home fire alarm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To operate a control part of a home fire alarm at a voltage lower than the voltage of a power supply battery and to suppress the power consumption. <P>SOLUTION: The home fire alarm includes: a detection part 11 which detects a fire; an alarm output part 14 which issues an alarm sound; a control part 15 which controls the detection part 11 and the alarm output part 14; a power supply battery 16 which supplies first power to the alarm 1; and a converter 17 which decreases voltage of the first power for supplying power to the control part 15 as second power. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an improvement of a fire alarm installed on a wall surface or ceiling surface of a house.

  Recently, residential alarms that operate using batteries as a power source are commercially available. In such a fire alarm, it is extremely important to reduce power consumption and extend the life of the power battery.

  Many techniques for suppressing the power consumption of a home alarm device have been proposed. For example, in Patent Document 1 below, the number of times that scattered light from smoke is detected in a photoelectric smoke detector is a predetermined value or more. Then, it is described that the light emission interval is shortened and the power consumption is saved by always setting the light emission interval to be long.

  Further, in Patent Document 2, in the photoelectric dust sensor device, the output level of the signal output to the microcomputer after a very short time from the LED driving time is equal to or lower than the preset output level. In this case, the current for driving the LED is cut off, and the pulse width of the pulse signal is made smaller than the pulse width determined as MAX, so that the driving power of the LED when no foreign object is detected can be reduced. Are listed.

Japanese Patent Laid-Open No. 05-073785 JP 2005-214835 A

  By the way, home alarm devices often use a microcomputer integrated with a CPU, a timer circuit, and the like as a control unit. However, a microcomputer for such a device has a low voltage to achieve low power consumption. There is something that works. However, if the output voltage of the battery serving as the power supply for the residential alarm is too high compared to the specifications of the low voltage type microcomputer, there is a problem that power consumption cannot be suppressed.

  Then, this invention makes it a subject to operate the control part of a residential alarm device with a voltage lower than a power supply battery, and to suppress power consumption.

  A fire alarm for a house according to the present invention includes a detection unit that detects the occurrence of a fire, an alarm output unit that sounds an alarm sound, a control unit that controls the detection unit, and the alarm output unit, and a first device. And a converter that steps down the first power source and supplies the second power source to the control unit.

  The said structure WHEREIN: You may further provide the power supply selection means which selects any one of a said 1st power supply and a said 2nd power supply, and supplies to the said control part.

  The power source selection unit may supply the first power source to the control unit while the alarm output unit is operating.

  In addition, the determining means for determining whether or not the voltage level of the first power supply has decreased below a predetermined reference value, and the voltage level of the first power supply has decreased below the predetermined reference value by the determining means. A fire alarm for a house further comprising overdischarge prevention means for electrically shutting off the power supply battery when it is detected.

  The power supply selecting means further comprises first determining means for determining whether or not the voltage level of the first power supply has dropped below a first reference value, and the power supply selecting means is configured to detect the first power supply by the first determining means. When it is detected that the voltage level of one power source is lower than the first reference value, the first power source may be supplied to the control unit.

  Further, the second determination means for determining whether or not the voltage level of the first power supply has decreased below a second reference value lower than the first reference value, and the second determination means, When it is detected that the voltage level of the first power supply is lower than the second reference value, an overdischarge preventing means for electrically cutting off the power supply battery may be further provided.

  According to the present invention, the converter is configured to step down the first power source output from the power supply battery and supply the second power source to the control unit, so that the control unit can be operated at a low voltage, Low power consumption. In addition, it is desirable to operate each part other than a control part with the 1st power supply which a power supply battery outputs.

  In the configuration including the power source selection means for selecting one of the first power source and the second power source and supplying the first power source to the control unit, the control is performed according to the operating state of the apparatus or the state of battery consumption. By supplying the first power supply to the unit, malfunction of the control unit can be prevented.

  In the configuration in which the power source selection means supplies the first power source to the control unit while the alarm output unit is operating, particularly when the alarm output unit with large power consumption is activated, that is, when the alarm sound is sounded, A malfunction of the control unit can be reliably prevented.

  When it is detected by the determining means that determines whether or not the voltage level of the first power supply has dropped below a predetermined reference value, and the determining means, the voltage level of the first power supply has dropped below a predetermined reference value, In the configuration further provided with the overdischarge prevention means for electrically cutting off the power supply battery, liquid leakage and damage due to overdischarge of the power supply battery can be prevented.

  In addition, a first determination unit that compares the voltage level of the first power source with the first reference value is provided, and the power source selection unit determines that the voltage level of the first power source is the first level by the first determination unit. In the configuration in which the first power source is supplied to the control unit when it is detected that the voltage level of the second power source is too low due to battery consumption, By supplying the first power supply, it is possible to reliably prevent malfunction of the control unit.

  Then, the voltage level of the first power supply is determined by the second determination means that compares the voltage level of the first power supply with the second reference value that is lower than the first reference value, and the second determination means. In a configuration further comprising an overdischarge prevention means for electrically shutting off the power supply battery when it is detected that the voltage has fallen below the second reference value, liquid leakage or damage due to overdischarge of the power supply battery can be prevented.

These are the block diagrams which showed the basic composition of the Example. These are the perspective views which showed the external appearance of the Example. These are the block diagrams which showed the basic composition of the modification. These are the block diagrams which showed the basic composition of the other modification.

  The embodiment is a smoke alarm that is operated by a power source battery and detects smoke particles by light, and is installed on a wall surface or a ceiling surface of a house. However, the present invention can also be applied to a thermal alarm device that detects the heat of a fire. It can also be applied to gas leak alarms.

  As shown in FIG. 1, the fire alarm 1 includes a detection unit 11 including a light emitting element 11a such as a light emitting diode and a light receiving element 11b such as a photodiode, a light emitting element driving circuit 12 that drives the light emitting element 11a, An alarm output unit 14 having a speaker 13 for generating an alarm sound in the event of a fire, a control unit 15 comprising a microcomputer, a power supply battery 16, and a first power source output from the power supply battery 16 is stepped down to a second level. A DCDC converter 17 that outputs as a power source for power supply, an operation unit 18 that receives an alarm stop operation and the like, and a display lamp 19 that indicates the operating state of the apparatus.

  The detection unit 11 has a structure in which a light-emitting element 11a and a light-receiving element 11b are appropriately arranged inside a labyrinth (not shown) that blocks external light while allowing air to flow, and is covered with an insect-proof and protective cover 11c. In the state, it protrudes from the main body cover 1a. The smoke particles are detected by irradiating light from the light emitting element 11a toward the detection area inside the labyrinth, photoelectrically converting the reflected light from the smoke particles by the light receiving element 11b, and outputting the detection signal.

  In addition to the detection unit 11, the main body cover 1a is provided with a push button 18a constituting the operation unit 18, a display lamp 19, a sound hole 13a for the speaker 13, and the like, and the drawstring 18b is interlocked with the push button 18a. It is like that. Further, a substrate (not shown) on which the light emitting element driving circuit 12, the alarm output unit 14, the control unit 15 and the like are mounted, a speaker 13, and a power battery 16 are accommodated in the main body cover 1a.

  Next, the basic operation of the embodiment will be described. The control unit 15 repeatedly executes a monitoring mode for operating the detection unit 11 and a standby mode for stopping the detection unit 11 at a predetermined cycle. For example, the monitoring mode may be set to 1 second, and the standby mode may be set to 119 seconds.

  In the monitoring mode, the light emitting element 11a is turned on a predetermined number of times, and the level of the detection signal output from the light receiving element 11b at that time is compared with a threshold value. Then, it is determined whether or not a fire has occurred based on the number of times that the level of the detection signal exceeds the threshold, and when it is determined that a fire has occurred, the alarm output unit 14 is activated to start sounding the fire alarm. Further, the display lamp 19 is turned on. The sounding of the fire alarm and the lighting state of the display lamp 19 are continued until the alarm stop operation is performed by the operation unit 18.

  On the other hand, when it is not determined that a fire has occurred, the power consumption is suppressed by shifting to the standby mode and waiting for a predetermined time. A microcomputer for such a use is provided with a standby function that saves power by stopping most of the circuit. During the standby mode, the microcomputer constituting the control unit 15 may be set in a standby state. This standby state can usually be canceled by a timer interrupt or the like.

  In the embodiment, a first power source that is an output of the power battery 16 and a second power source in which the first power source is stepped down by the DCDC converter 17 are prepared. For example, the second power supply is set to 2.1 V or the like if the output voltage on the standard of the power supply battery 16 is 3 V. Here, it is assumed that the light emitting element driving circuit 12 and the control unit 15 can operate even when the voltage is less than 2V.

In the configuration of the present invention, when the currents flowing through the light emitting element driving circuit 12 and the control unit 15 are considered, the currents flowing through these circuits have a positive correlation with the power supply voltage applied thereto. That is, the current increases as the power supply voltage increases. Here, if the efficiency of the DCDC converter 17 is η, the current flowing from the power battery 16 to the DCDC converter 17 is Iv, and the current flowing from the DCDC converter 17 to the light emitting element driving circuit 12 and the control unit 15 is Iop,
Iv = Lop × 2.1 / 3 × 1 / η
However, if η> 0.7, Iv is smaller than Iop. Thus, in the present invention, the first power source output from the power battery 16 is stepped down by the DCDC converter 17 and supplied to the control unit 15 as the second power source. Can be operated with low power consumption.

  The modification of FIG. 3 includes a power source selection unit 20 that selects either the first power source or the second power source and supplies it to the light emitting element driving circuit 12 and the control unit 15 in the above embodiment. Furthermore, it is set as the structure provided. The power source selection means 20 can be constituted by a switch element or a relay. Constituent elements common to the example of FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. The basic operation of this example is the same as that of the example of FIG.

  With such a configuration, it is possible to prevent malfunction of the control unit 15 due to insufficient voltage by supplying the first power source to the control unit 15 according to the operating state of the apparatus or the consumption state of the power supply battery 16. .

  The power source selection unit 20 may supply the first power source to the light emitting element driving circuit 12 and the control unit 15 while the alarm output unit 14 is operating. In this way, it is possible to reliably prevent malfunction of the control unit 15 even when the alarm output unit 14 that consumes particularly large power is operated, that is, when an alarm sound is sounded.

  Note that it is more desirable from the viewpoint of low power consumption that the DCDC converter 17 is stopped while the power source selection unit 20 supplies the first power source to the light emitting element driving circuit 12 and the control unit 15. .

  The first power source voltage level, that is, whether or not the output voltage of the power source battery 16 has decreased below the first reference value is provided with a first determination unit 21, and the power source selection unit 20 includes the first power source selection unit 20. A configuration may be adopted in which the first power supply is selected and supplied to the control unit 15 when the determination unit 21 detects that the voltage level of the first power supply has decreased below the first reference value. In this way, when the voltage level of the second power source is excessively reduced due to the consumption of the power battery 16, the first power source is supplied to the control unit 15, so that the control unit 15 Can be reliably prevented.

  Alternatively, when the voltage level of the first power source is compared with the voltage level of the second power source and the difference is smaller than a predetermined value, the power source selecting unit 20 switches the first power source to the control unit 15. In the meantime, the DCDC converter 17 may be stopped. This is to prevent an excessive current from flowing from the power battery 16 because the efficiency of the DCDC converter 17 is less than 1 when the difference in voltage level between the input and output of the DCDC converter 17 is small. .

  The modified example of FIG. 4 is an improvement of the example of FIG. 3, in which a second level for determining whether or not the voltage level of the first power supply has dropped below a second reference value that is lower than the first reference value. When it is detected by the determination means 22 and the second determination means 22 that the voltage level of the first power supply has dropped below the second reference value, the overdischarge prevention means 23 that electrically shuts off the power supply battery 16. Are further provided. The overdischarge prevention means 23 can be constituted by a switch element or a relay. Constituent elements common to the example of FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.

  With such a configuration, liquid leakage and damage due to overdischarge of the power supply battery 16 can be prevented. The basic operation of this example is the same as that of the example of FIG. In the example of FIG. 1, the voltage level of the first power supply is determined by the determination means 22 for determining whether or not the voltage level of the first power supply has dropped below a predetermined reference value. When it is detected that the value is lower than the value, an overdischarge preventing means 23 for electrically shutting off the power supply battery 16 may be further provided.

DESCRIPTION OF SYMBOLS 1 Fire alarm device 11 Detection part 14 Alarm output part 15 Control part 16 Power supply battery 17 Converter 20 Power supply selection means 21 First discrimination means 22 Second discrimination means 23 Overdischarge prevention means

Claims (6)

A detector for detecting the occurrence of a fire;
An alarm output unit that sounds an alarm sound;
A control unit for controlling the detection unit and the alarm output unit;
A power supply battery for supplying a first power source to the device;
A residential fire alarm comprising a converter that steps down the first power source and supplies the second power source to the control unit. In claim 1,
A residential fire alarm further comprising power selection means for selecting one of the first power source and the second power source and supplying the selected one to the control unit. In claim 2,
The fire alarm device for a house, wherein the power source selection unit supplies the first power source to the control unit while the alarm output unit is operating. In any one of Claims 1-3,
Determining means for determining whether or not the voltage level of the first power supply has decreased below a predetermined reference value;
Residential fire alarm further comprising overdischarge prevention means for electrically disconnecting the power supply battery when the determination means detects that the voltage level of the first power supply has dropped below the predetermined reference value. vessel. In claim 2 or 3,
First discriminating means for discriminating whether or not the voltage level of the first power source has dropped below a first reference value;
The power source selection unit supplies the first power source to the control unit when the first determination unit detects that the voltage level of the first power source is lower than the first reference value. A fire alarm for residential use. In claim 5,
Second determining means for determining whether or not the voltage level of the first power supply has dropped below a second reference value lower than the first reference value;
When the second determining means detects that the voltage level of the first power source is lower than the second reference value, it further comprises overdischarge preventing means for electrically cutting off the power battery. Residential fire alarm.

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