JP3479169B2 - Receiver circuit of fire alarm receiver - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving circuit of a fire alarm receiver in which a fire detector is connected to a detector line drawn out in a warning area.

[0002]

2. Description of the Related Art Conventionally, in a power supply device of a fire alarm receiver of this type, when a power supply voltage is supplied to a receiver circuit provided for each of a plurality of sensor lines, the power supply voltage is supplied to each receiver circuit at once. A constant voltage circuit is provided to stabilize the power supply voltage. Therefore, the constant voltage circuit of the power supply device needs to be configured as a circuit corresponding to the power supply capacity in consideration of the maximum number of lines connectable to the receiver.

[0003]

However, in such a conventional constant voltage circuit for a fire alarm receiver, a circuit having a power commensurate with the power supply capacity of the maximum number of connectable sensor lines is prepared. Therefore, a transistor with high power is required for the stabilizing operation used in the constant voltage circuit, and when the power is increased, the structure for heat dissipation becomes complicated and large. The present invention, in which the ratio of the constant voltage circuit to the power supply device is large and the cost is high, has been made in view of such problems,
An object of the present invention is to provide a receiving circuit of a fire alarm receiver which keeps the power supply to the sensor line stable and eliminates the complexity of the structure for heat dissipation.

[0004]

SUMMARY OF THE INVENTION To this end, the present invention provides a plurality of receivers that are brought into a security zone.
The detector by connecting a plurality of fire detectors in line, the sensor supplies a power supply voltage for the fire detector driven line, the sensor lines in the fire detector detects the fire low impedance the receiving circuit of a fire alarm receiver provided separately for each of the sensor lines which detects the increase in the line current and outputs a fire detection signal by shorting, the sensor times
Receive the constant voltage circuit in the power supply voltage supply line for the line
It is characterized in that each circuit is individually provided.

By providing a constant voltage circuit in each of the receiving circuits provided for each sensor line in this way, each constant voltage circuit is
A small constant-voltage circuit that supports the power supply capacity for one line is enough, and the drive transistor used in the constant-voltage circuit also has a small power
Be of, without requiring special heat dissipation structure, the circuit scale can be reduced. In addition to the constant voltage circuit, each receiving circuit is equipped with a current limiting circuit that limits the line current flowing in the sensor line to within the specified value, and the driving element of the constant voltage circuit is shared as a part of the driving element of the current limiting circuit. To do.

When the current limiting circuit is added to each constant voltage circuit as described above, the receiving circuit limits the line voltage at the same time as making the constant voltage for each sensor line and suppresses the line current when the sensor is issued. The current consumption as a whole is reduced. Conventionally, there is a simple current limiting circuit, but by integrating it with a constant voltage circuit, the transistor of the constant voltage circuit can be shared as a switching element for current limiting, and when the current limiting circuit is provided independently. In addition to the addition of the constant voltage function, the circuit configuration can be simplified by sharing the transistor.

Further, a reset circuit is provided to cut off the drive element of the constant voltage circuit to cut off the current supplied to the sensor line when a reset signal accompanying the recovery operation of the receiver is supplied. . When such a reset circuit is added, the constant voltage circuit, the current limiting circuit and the recovery circuit can be realized as one circuit unit, and the circuit sharing can be further promoted to make all the circuits required for the receiver circuit of the receiver compact. You can

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall structure of the present invention.
From the fire alarm receiver 1, sensor lines 2-1 to 2-n that function as power source / signal lines are drawn out. A plurality of fire detectors 3 are connected to each of the detector lines 2-1 to 2-n, and a termination resistor 4 for detecting disconnection is further connected to the end.

The fire alarm receiver 1 has sensor lines 2-1 to 2-1.
Receiving circuits 5-1 to 5-n are provided corresponding to 2-n. The receiving circuits 5-1 to 5-n are connected to the sensor lines 2-1 to 2-1.
The fire detector 3 connected to 2-n detects a fire and detects an increase in current flowing by short-circuiting the lines to a low impedance, and outputs a fire reception signal. Each of the receiving circuits 5-1 to 5-n is connected to the MPU 6.

For the MPU 6, an operation unit 7, a display unit 8, a main sound unit 9, a district sound control unit 10, and a transfer unit 31.
Are connected. Bell line 1 from the district sound control unit 10
1 is pulled out, and the district bell 12 is connected to the bell line 11. When the MPU 6 receives a fire reception signal from any of the receiving circuits 5-1 to 5-n, it displays a representative fire on the display unit 8 and opens the detector line connecting the fire detector 3 that has detected the fire. Display the indicated fire area.

At the same time, the main acoustic section 9 is driven to output a fire alarm. It also drives the district sound control unit 10, and the bell line 11
The district bell 12 is sounded by supplying the drive voltage to the. The ringing of the district bell 12 by the district sound control unit 10 is performed by ringing or ringing stop according to the operation state of the district bell stop switch provided in the operation unit 7. Furthermore, MPU6
The transfer unit 31 is caused to output a transfer signal for displaying a transfer.
An external display unit 30 is connected to the transfer unit 31 as necessary, and the external display unit 30 installed apart from the fire alarm receiver 1 can also display a fire alarm.

Further, the fire alarm receiver 1 includes a power supply unit 13
Is provided. The power supply device 13 receives the commercial AC 100V, reduces the voltage to a predetermined voltage, and supplies the power supply voltage to each unit. Further, the power supply device 13 is provided with a battery as a backup power supply, and when the commercial AC 100V is in a power failure, it is switched to the backup power supply so that backup can be performed. Further, the MPU 6 has an AD converter 6a.
Is provided, and the received voltage obtained according to the line current is converted into digital data and taken into the MPU 6.

FIG. 2 shows a concrete circuit configuration of the receiving circuit 5-1 shown in FIG. First, the constant current conversion circuit 15 and the scan circuit 16 are provided. The scan circuit 16 is the MPU of FIG.
6 when a scan signal is supplied, the output current I obtained by multiplying the line current I1 from the constant current conversion circuit 15 by a predetermined ratio.
2 is output. The current I2 is supplied to the resistor R30, converted into the signal voltage V, and input to the AD converter 6a of the MPU 6 in FIG. The constant current conversion circuit 15 converts, for example, the current of the line current I1 into 1/10, outputs the current of I2, and converts it into a voltage signal by the resistance of R30.

A constant voltage circuit 17 is provided following the constant current conversion circuit 15. The constant voltage circuit 17 is composed of a resistor R1, a capacitor C1, a constant voltage diode ZD1, and a transistor Q1, and stabilizes the power supply voltage Vin supplied from the power supply device 13 to the receiving circuit to, for example, 24V, and the sensor line 2-1. Supply to. That is, the input voltage Vin is stabilized to a constant voltage determined by the Zener voltage of the constant voltage diode ZD1 and supplied to the sensor line 2-1.

The constant voltage circuit 17 eliminates fluctuations in the power supply voltage supplied to the fire detector 3. Conventionally, the power supply voltage Vin of the power supply device 13 supplied to the receiving circuit 5-1 is made into a constant voltage collectively for all the detector lines.
If the alarm current per unit is set to 60 mA, it is necessary to have a capability of supplying a current obtained by multiplying the number of alarms by the number of lines in consideration of simultaneous alarms from the sensors of a plurality of lines. For this reason, the conventional radiator of the constant voltage circuit needs to have a large heat radiation power, requires a low thermal resistance and a large heat radiation area, and the constant voltage circuit becomes large.

However, in the embodiment of FIG. 2, the constant voltage circuit 17 is provided in each of the receiving circuits, so that the constant voltage circuit 17 is provided.
Since the transistor Q1 has a low current capacity and requires a small power, a special heat radiation structure is not required, and the circuit configuration can be downsized and the cost can be reduced. FIG. 3 shows another embodiment of the receiving circuit of the present invention, which is characterized in that the constant voltage circuit 17 of FIG. 2 is provided with a current limiting circuit 18 including a resistor R2 and a transistor Q2. Current limiting circuit 18
Is a feedback circuit that biases the base and emitter of the transistor Q2 with the voltage drop generated by the resistor R2 and further controls the base current of the transistor Q1 of the constant voltage circuit 17 as the collector current of the transistor Q2 to form a feedback circuit. ing.

Therefore, when the number of fire detectors 3 exceeding the specified number is simultaneously issued and the current flowing in the detector line 2-1 increases and exceeds the specified value, the voltage drop across the resistor R2 causes the base of the transistor Q2 to drop. The voltage between the emitters increases and the collector current increases. Therefore, the base-emitter voltage of the transistor Q1 is suppressed by turning on the transistor Q2, and current limiting is performed to suppress further increase in the collector current flowing through the transistor Q1.

In this case, the current limiting circuit 18 shares components with each other by combining with the constant voltage circuit 17. That is, the transistor Q1 and the resistor R1 can be shared by both circuits, and both circuits can be configured with the minimum necessary parts. FIG. 4 shows another embodiment of the present invention, which is characterized in that a reset circuit 19 constituted by a transistor Q3 and resistors R3 and R4 is further provided in the embodiment of FIG. The reset circuit 19 operates in response to the reset signal obtained by operating the recovery switch of the fire alarm receiver 1 while the line current is flowing when the transistor Q1 of the constant voltage circuit 17 is turned on when the fire detector 3 is in the alarm state. Turn on Q3. When the transistor Q3 is turned on, the transistor Q1 is cut off to cut off the current supplied to the fire detector 3 and can be restored by resetting the power supply of the fire detector 3.

Also in this case, the reset circuit 19 and the constant voltage circuit 17 are combined to share components. That is, the transistor Q1 and the resistor R1 can be shared by both circuits, and both circuits can be configured with the minimum necessary parts.

[0020]

According to the present invention as described above, according to the present invention, sensitive
By providing a constant voltage circuit for each receiver circuit provided for each intelligent circuit, each constant voltage circuit can be a small constant voltage circuit corresponding to the power supply capacity for one line, and can be used for a constant voltage circuit. The drive transistor also needs a small power , does not require a special heat dissipation structure, and has a small circuit scale and a low cost.

Further, by adding a current limiting circuit to each constant voltage circuit, the receiving circuit simultaneously regulates the voltage of each sensor line and simultaneously limits the current, thereby suppressing the line current when the sensor is issued and overall. Reduce current consumption. Also, by integrating the current limiting circuit and the constant voltage circuit, the transistor of the constant voltage circuit can be shared as a switching element for current limiting, and the constant voltage function is added compared to the case where the current limiting circuit is provided alone. At the same time, the circuit configuration can be simplified by sharing the transistors.

Further, by adding a reset circuit, the constant voltage circuit, the current limiting circuit and the recovery circuit can be realized as one circuit unit. Further sharing of the circuit will make it necessary for the receiving circuit of the receiver. All circuits can be made compact and costs can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of an apparatus to which the present invention is applied.

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is a block diagram showing another embodiment of the present invention.

FIG. 4 is a block diagram showing another embodiment of the present invention.

[Explanation of symbols]

1: Fire alarm receiver 2: Sensor line 3: Fire detector 4: Termination resistance 5: Receiver circuit 6: MPU 6a: AD converter 15: Constant current conversion circuit 16: Scan circuit 17: Constant voltage circuit 18: Current limiting circuit 19: Reset circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masashi Arikawa 2-1043 Kamiosaki, Shinagawa-ku, Tokyo Within Hochiki Co., Ltd. (56) References JP-A-7-175981 (JP, A) JP-A 6-186090 (JP, A) JP-A-7-160666 (JP, A) JP-A-59-207737 (JP, A) Actual development S61-30196 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G08B 17/00 G08B 23/00-31/00

Claims (3)

(57) [Claims] 1. A plurality of drawn into security area from the receiver
A plurality of fire detectors are connected to the detector line, a power supply voltage for driving the fire detector is supplied to the detector line, and when the fire detector detects a fire, the detector line is short-circuited to a low impedance. the sensor in the receiving circuit of a fire alarm receiver provided separately for each line, the constant voltage circuit in the power supply voltage supply line against the sensor line to detect an increase in the line current and outputs a fire detection signal due to A receiving circuit for a fire alarm receiver, characterized in that each of the receiving circuits is individually provided. 2. The fire alarm receiver receiving circuit according to claim 1, further comprising a current limiting circuit for limiting a line current flowing through the sensor line to within a specified value, and driving the current limiting circuit. A receiving circuit for a fire alarm receiver, characterized in that the constant voltage circuit driving element is shared as part of the element. 3. The fire alarm receiver receiver circuit according to claim 1 or 2, further comprising: driving the constant voltage circuit when a reset signal associated with a receiver recovery operation is supplied. A receiver circuit for a fire alarm receiver, comprising a reset circuit for controlling cutoff of an element to cut off a current supplied to a detector line.