JP2011197861A - Alarm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alarm capable of more accurately detecting a decreased battery voltage with a small configuration.SOLUTION: In the alarm including a heat detector 40 and a smoke detector 50 as state detectors, a controller 11, an integrated circuit 10, and a battery 1 as a power source, the alarm further includes: a voltage detection circuit 15 for detecting the applied voltages, including a reference voltage input unit to which a predetermined reference voltage is applied and a power voltage input unit to which a battery voltage is applied; a detected voltage changeover switch 20 for selectively connecting the voltage detection circuit 15 to a reference voltage supply unit 200 for supplying the reference voltage or the battery 1; a threshold setting unit 112 for storing into an EEP-ROM 2 the detected value of the voltage detection circuit 15 when the reference voltage is applied, as an abnormality decision threshold; and a battery exhaustion decision unit 113 for deciding the existence or non-existence of abnormality, on the basis of the detected value of the voltage detection circuit 15 when the battery voltage is applied and the abnormality decision threshold. At least the voltage detection circuit 15 is included in the integrated circuit 10.

Description

  The present invention relates to an alarm device using a battery as a power source.

Conventionally, a fire alarm for a house (hereinafter referred to as a home alarm) does not function due to a battery exhaustion when a fire occurs. A function is provided for notifying that the battery should be replaced.
In order to realize this function, the home alarm device has been provided with a mechanism for measuring the voltage of the battery. Specifically, for example, the voltage of the battery is measured by detecting the voltage of the battery and performing AD conversion with an AD converter built in the microcomputer. Here, since there is a limitation that the microcomputer cannot measure a voltage higher than its own reference voltage (Vref), it is necessary to make the measurement voltage smaller than Vref. For this reason, for example, a midpoint voltage (in this case, one half of the measured voltage) in which resistors with the same resistance value with high accuracy are connected in series is detected and AD converted. However, the resistors used for voltage detection have individual tolerances, and the AD converters also have individual conversion errors. Therefore, even when the same voltage is applied, there may be a difference in the measurement result of the voltage for each individual home guard.
Thus, since an error may occur in the voltage measurement result, it is necessary to set a value having a certain margin when presetting a threshold value for determining whether the battery has run out. For this reason, there was a case where the battery remaining amount of the home alarm was wasted.

  In addition, “In the completion stage at the time of manufacture of residential fire alarms, a standard voltage indicating a decrease in the battery voltage common to each residential fire alarm is applied to the detection terminal of the battery voltage detection circuit instead of the battery voltage. And the technique of memorize | storing the output in a memory | storage part as a fall reference value intrinsic | native to the said fire alarm for the said house is proposed (for example, refer patent document 1).

JP 2008-123347 A (5th page, 6th page, FIG. 1)

  According to the technique described in Patent Literature 1, since the threshold value is determined for each house alarm, it is possible to more accurately determine whether the battery has run out regardless of the voltage detection error of each house alarm. However, since the number of parts of the battery voltage detection circuit is large, the circuit is enlarged and the manufacturing cost is increased.

  The present invention has been made to solve the above-described problems, and provides an alarm device capable of more accurately detecting a decrease in battery voltage with a small configuration.

  An alarm device according to the present invention includes a state detection unit that detects a state change based on a physical phenomenon, a control unit that outputs an alarm based on an output signal of the state detection unit, and an integrated circuit, and powers the battery. An alarm device having a reference voltage input unit to which a predetermined reference voltage is applied and a power supply voltage input unit to which a battery voltage is applied, a voltage detection unit for detecting the applied voltage, and the voltage detection unit A reference voltage supply unit that applies the reference voltage or a switching unit that is selectively connected to the battery, and a threshold value that causes the storage unit to store the detection value of the voltage detection unit when the reference voltage is applied as an abnormality determination threshold value A setting unit; and an abnormality determination unit that determines presence / absence of an abnormality based on a detection value of the voltage detection unit when a battery voltage is applied and the abnormality determination threshold, and at least the voltage detection unit includes Included in the integrated circuit Is shall.

  According to the present invention, the reference voltage input unit to which the reference voltage supply unit is connected and the power supply input terminal to which the battery is connected have a voltage detection unit for detecting the applied voltage, and the voltage detection unit is a reference voltage supply unit. Or a switching unit selectively connected to the battery. Then, the presence or absence of abnormality is determined using the detection value of the voltage detection unit when a predetermined reference voltage is applied as an abnormality determination threshold value. Thereby, since the abnormality determination threshold value can be set for each individual alarm device, it is possible to obtain an abnormality determination threshold value corresponding to the error that the alarm device has for each individual, and to determine the presence or absence of abnormality with high accuracy. Further, since at least the voltage detection unit is included in the integrated circuit (ASIC), the circuit of the alarm device can be miniaturized and the alarm device can be further miniaturized.

It is a functional block diagram of the fire alarm device which concerns on embodiment. It is a flowchart which shows the battery deadline threshold setting process which concerns on embodiment. It is a flowchart which shows the battery exhaustion determination process which concerns on embodiment.

Embodiment.
Hereinafter, in the present embodiment, a case where the present invention is applied to a fire alarm device driven by a battery will be described as an example.
FIG. 1 is a functional block diagram showing a circuit configuration of a fire alarm 100 according to an embodiment of the present invention.
In FIG. 1, a fire alarm 100 includes a battery 1, an EEP-ROM 2, an inspection switch 3, an integrated circuit 10, a detection voltage changeover switch 20, a heat detection unit 40, a smoke detection unit 50, an alarm sound. A control circuit 60 and an indicator lamp circuit 70 are provided. Further, the fire alarm device 100 can be connected to a reference voltage supply unit 200 that applies a predetermined voltage.

  The integrated circuit 10 includes a CPU (hereinafter referred to as a control unit 11) that is a control unit, a constant voltage circuit 12, a reset unit 13, an oscillation unit 14, and a voltage detection circuit 15.

  The constant voltage circuit 12 supplies the power supply voltage of the battery 1 to the control unit 11 and the like as a predetermined constant voltage power supply (for example, a voltage of about 2.3 V).

The reset unit 13 puts the control unit 11 in a reset state when the power is turned on, and releases the reset state after a predetermined time to make it an operable initial state. Further, when the voltage applied to the control unit 11 becomes smaller than the operation guarantee voltage of the control unit 11, the control unit 11 is reset.
The oscillation unit 14 supplies a clock signal to the control unit 11.

  The voltage detection circuit 15 detects the applied voltage and outputs a voltage detection signal corresponding to the detected voltage to the control unit 11. The input side of the voltage detection circuit 15 is connected to a detection voltage changeover switch 20, and is connected to a predetermined reference voltage supply unit 200 or the battery 1 via the detection voltage changeover switch 20. That is, the voltage detection circuit 15 can detect the voltage applied by the reference voltage supply unit 200 or the battery 1.

The control unit 11 performs overall control of the fire alarm device 100, periodically takes in signals from each internal circuit, and performs processing according to the signals. For example, when the control unit 11 takes in a signal (fire detection signal) from the light receiving amplifier 53 of the smoke detection unit 50, it is determined whether or not an alarm is necessary based on the fire detection signal. When the control unit 11 takes in the fire detection signal and determines that the alarm sound is necessary, the control unit 11 outputs the sound data of the alarm sound to the alarm sound control circuit 60.
Furthermore, the control unit 11 includes an AD conversion unit 111, a threshold setting unit 112, and a battery exhaustion determination unit 113.

The AD conversion unit 111 converts the voltage detection signal from the voltage detection circuit 15 into a voltage detection value (digital signal).
The threshold setting unit 112 detects a voltage detection value of the voltage detection circuit 15 when a voltage is applied by the reference voltage supply unit 200 that applies a predetermined reference voltage indicating battery exhaustion, and a threshold for detecting a decrease in battery voltage. Is stored in the EEP-ROM 2 as a voltage (hereinafter referred to as a battery exhaustion threshold).
The battery exhaustion determination unit 113 compares the voltage detection value of the voltage detection circuit 15 when a voltage is applied by the battery 1 with the battery exhaustion threshold stored in the EEP-ROM 2, and the voltage of the battery 1 is determined to be the battery exhaustion threshold. In the case of the following, the battery 1 is detected to be out of voltage. Note that the battery exhaustion determination unit 113 corresponds to the abnormality determination unit of the present invention.
Since the control unit 11, the constant voltage circuit 12, the reset unit 13, the oscillation unit 14, and the voltage detection circuit 15 of FIG. 2 are included in at least the integrated circuit (ASIC) 10, the circuit is sufficiently miniaturized.

The detection voltage changeover switch 20 is controlled by the control unit 11 to switch the voltage supply source connected to the input side of the voltage detection circuit 15. One contact of the detection voltage changeover switch 20 is a reference voltage input terminal 21, which is connected to the reference voltage supply unit 200. The other contact of the detection voltage changeover switch 20 is a battery voltage input terminal 22 and is connected to the battery 1. That is, the voltage detection circuit 15 is selectively connected to either the reference voltage supply unit 200 or the battery 1 by the detection voltage changeover switch 20.
Since the configuration is as described above, the reference voltage input unit of the present invention corresponds to the input terminal of the voltage detection circuit 15 when the detection voltage changeover switch 20 is connected to the reference voltage input terminal 21, and the power supply voltage of the present invention. The input unit corresponds to an input terminal of the voltage detection circuit 15 when the detection voltage changeover switch 20 is connected to the battery voltage input terminal 22. In addition, the switching unit of the present invention corresponds to the control unit 11 and the detection voltage switch 20.

  The EEP-ROM 2 is a storage unit that stores programs executed by the control unit 11 and various data. The EEP-ROM 2 stores a battery exhaustion threshold that is a voltage serving as a threshold for detecting battery exhaustion.

  The inspection switch 3 is a switch for accepting a pressing operation by a user such as a resident and operating the inspection mechanism. When the inspection switch 3 is pressed, the control unit 11 takes in a pressing signal of the inspection switch 3 and determines whether or not the input of the inspection switch 3 is confirmed. When the control unit 11 determines that the input of the inspection switch 3 has been confirmed, the control unit 11 transmits a signal for starting an inspection related to an operation such as an alarm sound or an indicator light.

The heat detection unit 40 and the smoke detection unit 50 correspond to the state detection unit of the present invention, detect a state change based on a physical phenomenon, and output a signal corresponding to the detected content to the control unit 11. Note that only one of the smoke detection unit 50 and the heat detection unit 40 may be provided as the state detection unit.
The heat detection unit 40 is composed of a fixed resistor 41 and a temperature sensor using a thermistor 42. An intermediate potential between the fixed resistor 41 and the thermistor 42 is an output terminal of the heat detection unit 40, and a temperature detection signal is transmitted to the control unit 11 through the output terminal. The thermistor 42 has a temperature characteristic in which its resistance value varies according to the environmental temperature. Since the temperature characteristic of the thermistor 42 is linearized by the compensation fixed resistor 41, a detection voltage (temperature information) corresponding to the environmental temperature is input to the output terminal.

  The smoke detector 50 includes an infrared LED 54 that is a light emitting element, and an infrared LED drive circuit 51 that supplies a current pulse to the infrared LED 54 when receiving a light emission control pulse from the controller 11. Further, the smoke detector 50 includes a light receiving element (not shown) such as a photodiode (PD) that receives scattered light generated by the smoke particles by the light irradiated from the infrared LED 54 into the optical bench. Light scattered by the light emitted from the outer LED 54 is received. Then, in the photodiode current-voltage conversion circuit 52 (described as a PD [IV] conversion circuit in FIG. 1), the current obtained based on the amount of scattered light received by the photodiode is converted into a voltage. The output level of the voltage is amplified with a predetermined gain in the light receiving amplifier 53 and transmitted to the control unit 11.

  The alarm sound control circuit 60 includes an audio D / A converter 61 (described as audio DAC & LPF in FIG. 1) having a low-pass filter, an audio amplifier 62 and a speaker 63 as sounding components. The low-pass filter serves to adjust the audio data transmitted from the control unit 11 in advance to a frequency band that is easy for the user to listen to.

  In the alarm sound control circuit 60, the audio data (digital signal) input from the control unit 11 is converted into an audio signal (analog signal) by the audio D / A converter 61 and output through a low-pass filter. Then, a volume control signal is transmitted from the control unit 11 to the audio amplifier 62, and the audio amplifier 62 adjusts the amplification degree of the audio signal (analog signal). The speaker 63 outputs the audio signal amplified by the audio amplifier 62.

  The indicator lamp circuit 70 displays the state of the fire alarm 100 on the red LED 72 connected to the confirmation lamp drive circuit 71. In addition, as a state of the fire alarm device 100, when the fire detection operation is normally performed (a fire is not detected and there is no abnormality in the remaining battery level or sensor device), the remaining battery level is low. If there is an abnormality caused by a device or an abnormality such as a sensor failure, a fire is detected and an alarm is output. The red LED 72 is provided in the housing of the fire alarm 100. In addition, although red LED72 is used as an indicator lamp, the kind and number are not specifically limited.

  The reference voltage supply unit 200 is connected to the fire alarm 100 via the detection voltage changeover switch 20 and applies a predetermined reference voltage indicating battery exhaustion. As the predetermined reference voltage indicating that the battery has run out, a voltage value is set such that the fire alarm device 100 can perform fire detection and alarm output.

Next, the fire detection operation of the fire alarm 100 will be described. Here, a case where smoke is detected to determine whether or not a fire has occurred will be described as an example.
The fire alarm 100 sets the power supply voltage supplied from the battery 1 to a predetermined constant voltage (for example, a voltage of about 2.3 V) stabilized by the constant voltage circuit 12, and the constant voltage power is supplied to the control unit 11 and the like. . The fire alarm device 100 performs a fire monitoring operation and an abnormality monitoring operation at a predetermined cycle timed by a timer unit included in the control unit 11. Next, the control unit 11 supplies a light emission control pulse to the infrared LED drive circuit 51 to cause the infrared LED 54 to emit light with a predetermined pulse width and a predetermined cycle.

  The photodiode in the smoke detector 50 is not arranged on the optical path of the infrared LED 54, and the light of the infrared LED 54 does not reach the photodiode directly. However, when smoke generated by a fire or the like is interposed between the photodiode and the infrared LED 54, the light of the infrared LED 54 is scattered by the smoke particles, and the photodiode receives the scattered light. .

  For the above reason, when no smoke is generated, the light emitted from the infrared LED 54 hardly reaches the photodiode. That is, since the signal amplified by the light receiving amplifier 53 is less than a predetermined reference value (fire occurrence level), a signal for operating the alarm sound control circuit 60 and the indicator lamp circuit 70 is output from the control unit 11. Not. Accordingly, the alarm sound control circuit 60 does not sound a sound alarm, and the indicator light circuit 70 does not display the red LED 72 that a fire has occurred.

  When smoke is generated, the light emitted from the infrared LED 54 is scattered by the smoke particles, and the scattered light reaches the photodiode. That is, since the signal amplified by the light receiving amplifier 53 is equal to or higher than a predetermined reference value, the control unit 11 determines that a fire has occurred and operates the alarm sound control circuit 60 and the indicator lamp circuit 70. Output a signal. Then, the alarm sound control circuit 60 sounds an alarm sound, and the indicator light circuit 70 causes the red LED 72 to display a fire.

  When the control unit 11 determines that no fire has occurred, the operation mode returns to the sleep mode.

  Next, a process for setting a battery exhaustion threshold for detecting battery exhaustion of the battery 1, which is a main part of the present invention, will be described. The setting of the battery exhaustion threshold is performed after the assembly of the part that affects the setting of the battery exhaustion threshold is completed, for example, when the assembly of the fire alarm 100 is completed or when it is installed in the monitoring target area. The setting process of the battery exhaustion threshold is started, for example, when the manufacturer or installer of the fire alarm device 100 operates a mode changeover switch (not shown) to give an instruction for setting the battery exhaustion threshold setting mode to the control unit 11. Is done.

FIG. 2 is a flowchart showing the battery depletion threshold setting process.
When the battery depletion threshold setting mode is set, first, the control unit 11 outputs a signal to the detection voltage changeover switch 20 to connect the reference voltage input terminal 21 side and the voltage detection circuit 15 (S1).
Next, when a predetermined reference voltage indicating battery exhaustion is applied by the reference voltage supply unit 200 (S2), the voltage detection circuit 15 outputs a voltage detection signal corresponding to the detected voltage to the control unit 11 (S3). .
The AD conversion unit 111 of the control unit 11 AD converts the voltage detection signal output from the voltage detection circuit 15 to obtain a voltage detection value (digital signal) (S4). Then, the threshold setting unit 112 stores the voltage detection value in the EEP-ROM 2 as the battery exhaustion threshold (S5).

Generally, an electronic component such as a resistor used in the voltage detection circuit 15 that detects a voltage has an allowable error for each individual. For this reason, even if the same voltage is applied, the voltage detection signal output from the voltage detection circuit 15 may vary somewhat from one individual to another. Further, the AD conversion unit 111 of the control unit 11 also has a conversion error for each individual. For this reason, even if the same voltage detection signal is input, there may be some difference in the converted digital signal for each individual.
However, in the fire alarm device 100 according to the present embodiment, the voltage detection signal of the voltage detection circuit 15 when a voltage indicating battery exhaustion is actually applied is converted into a digital signal by the AD converter 111 and the battery exhaustion is performed. It is stored in the EEP-ROM 2 as a threshold value. For this reason, the battery exhaustion threshold according to the peculiar difference of each fire alarm device 100 can be obtained.

  Next, the battery exhaustion determination process of the fire alarm device 100 during normal fire monitoring will be described. The battery exhaustion determination process is a process performed every predetermined time when the fire alarm 100 is installed in a monitoring target area such as a living room and performing normal fire monitoring.

FIG. 3 is a flowchart showing a battery exhaustion determination process.
During the fire monitoring, the control unit 11 outputs a signal to the detection voltage changeover switch 20 to connect the battery voltage input terminal 22 side and the voltage detection circuit 15 at the execution timing of the battery exhaustion determination process (S11). Thereby, a voltage is applied to the voltage detection circuit 15 by the battery 1.
The voltage detection circuit 15 outputs a voltage detection signal corresponding to the detected voltage to the control unit 11 (S12).
The AD conversion unit 111 of the control unit 11 AD converts the voltage detection signal output from the voltage detection circuit 15 to obtain a voltage detection value (hereinafter referred to as a battery voltage current value) (S13).

Next, the battery exhaustion determination unit 113 refers to the battery exhaustion threshold stored in the EEP-ROM 2 (S14), and compares the battery exhaustion threshold with the battery voltage current value (S15). If the current value of the battery voltage is equal to or greater than the battery exhaustion threshold, the process is terminated as it is because the battery is not exhausted.
On the other hand, if the current battery voltage value is less than the battery exhaustion threshold value in step S15, the battery exhaustion count is counted up (S16). Then, it is determined whether or not the number of times the battery has run out has reached the predetermined number of times (S17).

Further, if the number of battery exhaustion times has reached the determined number in step S17, a battery exhaustion determination process is performed (S18). That is, the number of times that the battery has been depleted (the number of times of battery depletion) is counted in the battery depletion determination process performed every predetermined time, and when the battery depletion count has reached a predetermined number of times, it is determined that the battery has run out It has been confirmed.
In the battery exhaustion confirmation process, for example, an alarm sound for notifying that the battery is exhausted is output, such as “Pi, battery exhausted”. Specifically, when the control unit 11 transmits audio data for notifying that the battery has run out to the audio D / A converter 61, the audio D / A converter 61 converts the audio data into an audio signal. The signal is input to the audio amplifier 62. Next, when the control unit 11 transmits a volume control signal for adjusting the output volume of the audio signal to the audio amplifier 62, the audio amplifier 62 adjusts the amplification level of the audio signal, and the audio signal with the adjusted amplification level is obtained. Is output as an alarm sound from the speaker 63.

  As described above, the fire alarm device 100 according to the present embodiment includes the voltage detection circuit 15 to which either the predetermined reference voltage indicating the battery exhaust voltage or the voltage of the battery 1 is selectively applied, and the battery The detection value of the voltage detection circuit 15 when a predetermined reference voltage indicating a dead voltage is applied is AD-converted, and is set as a dead battery threshold when determining whether the battery is dead. Since the battery exhaustion threshold value can be set for each individual fire alarm device 100, the battery exhaustion threshold value can be obtained according to the error that the voltage detection circuit 15 and the AD conversion unit 111 have for each individual object. For this reason, it is possible to determine whether the battery has run out with high accuracy, and to reduce waste of the remaining amount of the battery 1.

  Further, since the voltage detection circuit 15 is configured to be included in the integrated circuit (ASIC), the circuit of the fire alarm device 100 can be downsized, and the fire alarm device 100 can be configured more compactly and inexpensively.

In the present embodiment, an example in which the integrated circuit 10 including the voltage detection circuit 15 also includes the control unit 11, the constant voltage circuit 12, the reset unit 13, and the oscillation unit 14 is shown. The circuit may not include a control unit or the like. Moreover, it is good also as a structure which integrates | stacks the memory | storage part and switching part which store a battery exhaustion threshold value in the integrated circuit containing a voltage detection circuit.
In the present embodiment, the control unit 11 controls the detection voltage switch 20 to selectively connect the reference voltage supply unit 200 or the battery 1 to the voltage detection circuit 15. However, the configuration of the switching unit that selectively connects the reference voltage supply unit or the battery to the voltage detection unit is not limited to this. For example, the light receiving amplifier 53 and the thermistor 42 may be added to the switching destination of the switching unit. In this case, the switching unit changes the switching destination in accordance with the timing at which each state detection unit operates. By doing so, a plurality of detection signals can be processed by the AD converter.

  In the above description, a fire alarm having a smoke detector and a heat detector has been described as an example. However, a fire alarm having either a heat detector or a smoke detector, or other monitoring such as gas leakage The present invention can also be applied to an alarm device that detects a region abnormality.

  DESCRIPTION OF SYMBOLS 1 Battery, 2 EEP-ROM, 3 Inspection switch, 10 Integrated circuit, 11 Control part, 12 Constant voltage circuit, 13 Reset part, 14 Oscillation part, 15 Voltage detection circuit, 20 Detection voltage changeover switch, 21 Reference voltage input terminal, 22 battery voltage input terminal, 40 heat detection part, 41 fixed resistance, 42 thermistor, 50 smoke detection part, 51 infrared LED drive circuit, 52 photodiode current-voltage conversion circuit, 53 light receiving amplifier, 54 infrared LED, 60 alarm sound Control circuit, 61 Audio D / A converter, 62 Audio amplifier, 63 Speaker, 70 Indicator light circuit, 71 Confirmation light drive circuit, 72 Red LED, 100 Fire alarm, 111 AD converter, 112 Threshold setting unit, 113 Battery depletion determination unit, 200 reference voltage supply unit.

Claims (1)

A state detection unit for detecting a state change based on a physical phenomenon;
A control unit that outputs an alarm based on an output signal of the state detection unit;
In an alarm device comprising an integrated circuit and powered by a battery,
A voltage detection unit that has a reference voltage input unit to which a predetermined reference voltage is applied and a power supply voltage input unit to which a battery voltage is applied, and detects the applied voltage;
A switching unit that selectively connects the voltage detection unit to a reference voltage supply unit or a battery that applies the reference voltage;
A threshold value setting unit that stores a detection value of the voltage detection unit when a reference voltage is applied to the storage unit as an abnormality determination threshold value;
An abnormality determination unit that determines the presence or absence of an abnormality based on a detection value of the voltage detection unit when a battery voltage is applied and the abnormality determination threshold;
At least the voltage detection unit is included in the integrated circuit.

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