JPH0935157A - Power supply device for alarm receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve difficulty for uniformly holding the characteristics of respective batteries in a stand-by power supply and the expansion of a transformer and to improve the stability and reliability of the power supply. SOLUTION: This power supply device is provided with a DC power supply circuit 15 for rectifying and smoothing commercial AC voltage inputted through a transformer 14 and supplying prescribed DC voltage DC30V to a load, a stand-by power supply 20 for outputting DC voltage DC12V lower than the prescribed DC voltage 30V outputted from the circuit 15, a boosting circuit 21 for boosting the output voltage DC12V of the power supply 20 in order to obtain the prescribed voltage DC30V of the circuit 15, and a power supply switching circuit 16 for switching the circuit 15 to power supply based upon the stand-by power supply 20 and the circuit 21 when the AD power supply is interrupted and backing up the circuit 15. At the time of switching power supply, switching relay contacts 18a, 18b are turned to the (a) sides by turning off a relay 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply unit of an alarm receiver, for example, an alarm receiver that receives a signal from a fire detector to warn a fire.

[0002]

2. Description of the Related Art Conventionally, in a disaster prevention monitoring system using an alarm receiver which receives a detection signal from a fire detector to warn of a fire, a commercial alternating current is used in a power supply circuit of a receiver which operates on a commercial power source. A backup power supply is provided for backup in case of power failure. FIG. 4 shows a conventional receiver power supply circuit, which is an AC1 input to the primary winding 101a of the transformer 101.
00V is stepped down to AC26V by the secondary winding 101b and rectified by the diode bridge 102, and then the constant voltage circuit 10
In 3, the voltage is regulated to a specified voltage, for example, 24 V, and is supplied to the receiving circuit section of the load.

The transformer 101 has a secondary winding 101c for charging a battery 107 used as a standby power source,
The AC voltage 56V obtained in the secondary winding 101c is rectified by the diode bridge 109 to charge the battery 107. Further, a power supply switching circuit 104 is provided, and when the voltage comparator 105 detects that the output voltage of the constant voltage circuit 103 has dropped to, for example, 17 V or less, the relay 106 is turned off and the switching relay contact 106a is switched from the b side to the a side. By switching to, the power supply from the battery 107 is switched to backup.

[0004]

However, in such a conventional power supply device for an alarm receiver, the battery 107 of the standby power supply is also 24V in accordance with the power supply voltage supplied to the load. . As the battery 107, for example, a nickel-cadmium battery (nickel-cadmonium-alkaline battery) is used, and if the voltage of each nickel-cadmium battery is 1.2V, 20 batteries are forced to be connected in series to obtain 24V.

In this case, it is necessary to keep the characteristics of each battery uniform, and if batteries having different characteristics are mixed, there is a danger of heating, explosion, etc., so that manufacture is difficult. Further, the transformer 101 used in the power supply circuit uses a three-tap transformer including an input primary winding tap, a 24V secondary winding tap, and a 56V secondary winding tap. . By thus having the winding taps dedicated to charging the battery, the transformer 101 becomes large and the cost becomes high.

Further, the charging current is suppressed by charging the battery 107 through the charging resistor Rc. Therefore, even if the diode is damaged in the diode bridge 109 connected to the tap of the secondary winding 101c for 56V and a short circuit occurs, the short-circuit current is suppressed and the fuse in the primary side of the transformer 101 is suppressed. The FS could not be cut off, the transformer 101 became abnormally hot, and there was a risk of irritating odors that irritate the nose even if it did not ignite.

Therefore, it is an object of the present invention to provide a power supply device for an alarm receiver, which improves stability and reliability as a power supply.

[0008]

To achieve this object, the present invention is constructed as follows. First, the present invention is intended for a power supply device of an alarm receiver that receives a signal from a sensor and outputs an alarm. The commercial AC voltage input through a transformer is rectified and smoothed to a predetermined DC voltage, for example, DC30V. And a DC voltage lower than a predetermined DC voltage of 30 V output from the DC power circuit, for example, DC12
A backup power supply (battery) that outputs V, a booster circuit that boosts the output voltage DC12V of the backup power supply to a predetermined voltage DC30V of the rectifying and smoothing circuit, and a power supply by the backup power supply and the booster circuit from the DC power supply circuit when the AC power supply fails. A power supply switching circuit for switching and backing up is provided.

When the number of batteries connected in series is, for example, 12V, it is possible to reduce the standby voltage to half that of the conventional one by using such a low voltage, and it becomes easy to obtain the same characteristics when using a nickel-cadmium battery. Increased reliability. Here, the transformer has a single secondary winding tap, and the secondary winding tap is input-connected to the DC power supply circuit and the secondary tap is input-connected to the charging circuit of the standby power supply. For this reason, the structure of the transformer is simplified, the size can be reduced, and the cost can be reduced.

Further, when the standby power supply test switch is operated, the power supply switching circuit is operated to switch to the standby power supply, and the output of the booster circuit is connected to the dummy load to test the standby power supply including the booster circuit. To provide. By such a test of the backup power supply, a backup power supply test including the backup power supply and its booster circuit can be performed, and even if the backup power supply is lowered in voltage, its backup performance can be guaranteed through the backup power supply test.

Further, a predetermined voltage DC30V of the DC power supply circuit
Is provided with a low voltage DC power supply circuit which is supplied to the load by adjusting to a predetermined low voltage lower than the output voltage of the backup power supply, for example, DC10V or further DC5V, and when the power supply switching circuit switches to the backup power supply, A standby power supply bypass supply circuit for directly supplying the output voltage DC12V of the power supply to the low-voltage DC power supply circuit without passing through the booster circuit is provided.

Therefore, D lower than DC12V of the standby power source
The low-voltage DC power supply circuit that supplies C10V or DC5V is not supplied with DC30V boosted by the booster circuit, so that the loss due to boosting can be suppressed and the backup performance of the standby power supply can be effectively utilized.

[0013]

1 is an explanatory view of a fire alarm facility equipped with an alarm receiver in which the power supply device of the present invention is used.
In FIG. 1, from the 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 provided at the end.
Are connected.

The alarm receiver 1 has sensor lines 2-1 to 2-
Reception circuits 5-1 to 5-n are provided corresponding to 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 -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 control unit 6 using an MPU.

For the control unit 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.
Is 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 control unit 6 receives a fire reception signal from any of the receiving circuits 5-1 to 5-n, the control unit 6 displays a representative fire on the display unit 8 and a detector connected to the fire detector 3 that detects a fire. Fire area display showing the line.

At the same time, the main acoustic section 9 is driven to issue a fire alarm. Further, the district sound control unit 10 is driven, and the district bell 12 is rung by supplying a drive voltage to the bell wire 10. 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. Further, the control unit 6 causes the transfer unit 31 to output a transfer signal for displaying a transfer. If necessary, the external display unit 30 may be provided to the transfer unit 31.
Is connected to the alarm receiver 1, and the fire alarm can be displayed even on the external display unit 30 installed separately from the alarm receiver 1.

Further, the alarm receiver 1 is provided with a power supply device 13 which is the object of the present invention. The power supply device 13 receives supply of commercial AC 100V, and receives circuit parts 5-1 to 5-
n, DC2 for 24V drive unit such as district sound control unit 10
Supply a power supply voltage of 4V. Further, since the control unit 6, the display unit 8 and the like have circuit units which operate with a 10V power source or a 5V power source, DC10V and DC5V can be supplied to supply a power source voltage to these circuit units. . Further, DC30V is supplied to the 30V driving unit.

The power supply device 13 is provided with a battery as a standby power supply, as will be made clear later.
When a commercial power supply of 100V is cut off, it is switched to a backup power supply so that it can be backed up. FIG. 2 is a circuit diagram showing an embodiment of the power supply device according to the present invention provided in the alarm receiver 1 of FIG.

In FIG. 2, a commercial AC 100V is supplied to the primary winding 14a of the transformer 14 via a fuse FS1. The transformer 14 includes a primary winding 14a and a secondary winding 1
It has a simple structure with two winding taps provided with 4b.
In this embodiment, AC24V is applied to the secondary winding 14b.
(Effective value) is output. Following the transformer 14, a rectifying and smoothing circuit 15 is provided as a DC power supply circuit.

The rectifying / smoothing circuit 15 rectifies 24V AC of the secondary winding 14b of the transformer 14 by the diode bridge 15a via the fuse FS2 and further smoothes it by the capacitor C1 to obtain a DC voltage of about 30V. Rectifying smoothing circuit 1
The output of 5 is fuse FS3, diode D6, 24V
It is output to the load side as DC 24V via the constant voltage circuit 34. DC3 from the output side of the diode D6
0V is taken out.

On the other hand, a charging circuit 19 on the lower side is branched from the rectifying / smoothing circuit 15, and the charging circuit has a current limiting resistor R.
8 and a rectifying diode D5. The output of the charging circuit 19 is connected to the battery 20 as a standby power source via the fuse FS4. In the present invention, the battery as the standby power supply is supplied by the rectifying and smoothing circuit 15 D
A battery voltage of DC12V, which is about half that of C30V, is supplied. Therefore, when a NiCd battery is used for the battery 20, if the voltage is 1.2V per battery, 10
The batteries may be connected in series.

Therefore, the number of batteries used can be halved as compared with the conventional battery of 24V voltage shown in FIG. 4, and if the number of batteries is about 10, it is relatively easy to match the battery characteristics as compared with the conventional battery of 20 batteries. Therefore, the cost can be halved. Switching between the power supply by the rectifying / smoothing circuit 15 and the power supply by the battery 20 is performed by the power supply switching circuit 16. The power supply switching circuit 16 is a Zener diode ZD.
The decrease in the output voltage of the rectifying / smoothing circuit 15 is detected by the series circuit of 1 and the resistor R4. For example, the Zener voltage of the Zener diode ZD1 is selected so that the output voltage of the rectifying / smoothing circuit 15 is turned on at 12 V or more, and the resistance R
4, the zener diode ZD1 is turned off when the voltage falls below a specified voltage of about 17V, and a drop in the output voltage of the rectifying / smoothing circuit 15 and, in fact, a commercial AC100V power failure is detected.

The connection point between the Zener diode ZD1 and the resistor R4 is connected to the transistor Q1 via the resistors R5 and R6.
Connected to the base of. The transistor Q1 has a collector connected to the relay 18. If the output voltage of the rectifying / smoothing circuit 15 is 17 V or higher and normal, the Zener diode ZD
With the conduction of 1, the transistor Q1 receives the base bias and is turned on, and the relay 18 is driven. The relay 18 has switching relay contacts 18a and 18b.

The switching relay contact 18a is provided on the battery 20 side, and the switching relay contact 18b is provided on the 10V constant voltage circuit 22 side which will be made clear later. In addition, a resistor R is provided in parallel with the relay 18 at the collector of the transistor Q1.
An AC power supply lamp 17 using an LED is connected via 17. When the output voltage of the rectifying / smoothing circuit 15 is normal, the AC power supply lamp 17 is turned on by turning on the transistor Q1, and indicates that the commercial AC 100V is normally obtained.

Further, in the power supply switching circuit 16, the transistor Q2 is connected in parallel between the base and the emitter of the transistor Q1 via the resistor R6. The base of the transistor Q2 is connected to the MPU 24 used in the control unit 6 of the alarm receiver 1 of FIG. 1 via the resistor R7. In addition to the power switching by the hardware of the power switching circuit 16, the MPU 24 controls the transistor Q2 by the function of the power switching control unit 26 realized by the program control to add a predetermined condition to the power switching.

A power supply switching control unit 2 provided in the MPU 24
In order to monitor the power supply voltage required for No. 6, a series circuit of resistors R1 and R3 is provided following the capacitor C1 of the rectifying / smoothing circuit 15, and this divided voltage is input to the MPU 24 via the resistor R2. A booster circuit 21 is provided for the battery 20 provided as a standby power source. A DC-DC converter is used as the booster circuit 21. Boost circuit 2
To the input of 1, the + side of the battery 20 is connected via the switching relay contact 18a of the relay 18 provided in the power supply switching circuit 16. The switching relay contact 18a is a commercial AC10.
When 0V is normal, the relay 18 is turned on to switch to the b side, but when the commercial AC 100V fails, the relay 1
8 is turned off, and the switching relay contact 18a is switched to the side a in the figure.

Therefore, the DC 12V of the battery 20 is input to the booster circuit 21, and the booster circuit 21 inputs the input 12V to about 3V.
Boosts to 0V and outputs. The output of the booster circuit 21 is connected to the cathode side of the diode D6 via the diode D7. Therefore, the diodes D6 and D7 form a diode OR that switches between the power supply voltage of the rectifying / smoothing circuit 15 and the backup power supply voltage from the booster circuit 21.

Further, the output line of the booster circuit 21 is connected to a standby power supply lamp 28 using an LED via a resistor R9. In the standby power supply lamp 28, the switching relay contact 18a is switched to the a side as illustrated by the relay 18 being turned off by the power supply switching circuit 16, the battery voltage 12V is supplied from the battery 20, and the booster circuit 21 is boosted by 30V. Lights up when is output, indicating that standby power is being supplied normally.

Further, in the power supply device of the present invention, 10 V
A constant voltage circuit 22 and a 5V constant voltage circuit 23 are provided. 1
Since the 0 V constant voltage circuit 22 uses the display unit 8 and the like in FIG. 1 as a 10 V drive circuit, a power supply voltage of 10 V DC for this purpose.
Supply. The 5V constant voltage circuit 23 supplies an operating voltage DC5V to a circuit that operates at 5V including the MPU 24. 1
For the 0V constant voltage circuit 22, the 24V constant voltage circuit 34
DC24V stepped down is supplied through the b side of the switching relay contact 18b. That is, when the commercial AC 100V is normally obtained, the switching relay contact 18b is closed to the side b when the relay 18 is turned on, and the 10V constant voltage circuit 22 is provided.
DC24V is input to and is stepped down to produce DC10V. The output of the 10V constant voltage circuit 22 is further supplied to the 5V constant voltage circuit 23, and the input DC 10V is 5V.
It is stepped down to and outputs DC5V.

The switching relay contact 18b provided on the input side of the 10V constant voltage circuit 22 is directly supplied with the battery voltage of 12V from the battery 20 instead of the DC 30V boosted by the booster circuit 21. The booster circuit 21 from the battery 20 to the side a of the switching relay contact 18b
The circuit portion that directly supplies DC 12V of the battery 20 without passing through the battery can be called a standby power supply bypass supply circuit.

That is, when the battery 20 is switched to the standby power source as the driving power source, DC 24 V is obtained from the booster circuit 21 and the 24 V constant voltage circuit 34, but the boosted voltage of the booster circuit 21 is higher than that of the 10 V constant voltage circuit 22. Instead, the output voltage 12V of the battery 20 before boosting is directly supplied, whereby the 10V constant voltage circuit 22 and the 5V constant voltage circuit 23 can be efficiently supplied to the battery 20 without suffering a loss due to the boosting operation of the boosting circuit 21. Enables backup.

Next, the standby power supply test in the power supply device of FIG. 2 will be described. First, the standby power supply test switch 25 is connected to the MPU 24. While the standby power supply test switch 25 is turned on, the standby power supply test unit 27 realized by the program control of the MPU 24 operates. In order to enable the test operation by the standby power supply test unit 27, a standby power supply test circuit 32 is provided. Standby power supply test circuit 3
2 has a transistor Q3 which supplies the test signal E3 from the MPU 24 to the base via a resistor R14, the collector of the transistor Q3 is connected to the base of the transistor Q4 via a resistor R15, and is connected to the collector of the transistor Q4. Is connected to a dummy resistor R16 which allows a load current to flow in the standby power supply test.

The emitter of the transistor Q4 is the booster circuit 2.
1 output. Therefore, the backup power supply test circuit 32 causes a DC 30V output obtained by boosting the DC 12V output from the battery 20 by the booster circuit 21 to flow through the dummy resistor R16 to perform a test operation of the entire standby power supply including the battery 20 and the booster circuit 21. . Further, a standby power supply test result lamp 29 using an LED is connected to the MPU 24. The voltage monitoring by the MPU 24 during the standby power supply test monitors the output voltage of the battery 20 on the input side of the booster circuit 21 obtained via the switching relay contact 18a. Therefore, the input from the booster circuit 21 is branched to MP.
A voltage input circuit 23 that supplies the voltage signal E4 to U24 is provided. The voltage input circuit 23 includes resistors R10 and R
The input voltage is divided at 11, and a Zener diode ZD2 for a limiter is connected between the resistors R12 and R13. In the preliminary test operation by the preliminary power supply test unit 27 provided in the MPU 24 when the standby power supply test switch 25 is turned on, first, the MPU 24 inputs the power supply switching signal E1 to the transistor Q2 of the power supply switching circuit 16 to turn it on.

As a result, the transistor Q1 is forcibly cut off to turn off the relay 18, and the switching relay contact 18
Pseudo AC10 for switching a and 18b to the illustrated side a
Creates a 0V blackout condition. Next, the standby power supply test circuit 3
2, the test signal E3 is output to turn on the transistor Q3, the transistor Q3 is turned on to turn on the transistor Q4, and the dummy resistor R16 is output to the booster circuit 21.
And connect a dummy load to pass the load current for the preliminary power supply test.

At this time, since 24V DC is also supplied to the receiving circuit side via the diode D7, in addition to the power supply to the normal load, the dummy resistor R
A load current due to the connection of 16 will flow. The output voltage of the battery 20 under test by the operation of the standby power supply test circuit 32 based on the test signal E3 is branched from the input side of the booster circuit 21 and taken into the MPU 24 as the voltage signal E4, which is a predetermined regulated voltage, that is, the boosted voltage. For example, it is determined whether or not the output voltage of the standby power supply at which the circuit 21 can operate effectively is 10 V or higher, and the standby power supply test result lamp 29 is turned on while the output voltage is within the normal range. Of course, at this time, the standby power supply lamp 28 is also turned on if the output voltage of the booster circuit 21 is normal.

Next, the respective processing operations by the power supply switching control unit 26 and the standby power supply testing unit 27 provided in the MPU 24 of FIG. 2 will be described. First, the power supply switching process by the power supply switching control unit 26 will be described as follows. Commercial AC1
In the steady monitoring state where 00V is normally obtained,
The rectifying / smoothing circuit 15 outputs a predetermined power supply voltage DC of about 30V, and the zener diode Z of the power supply switching circuit 16 is output.
D1 conducts, transistor Q1 turns on and relay 18
Is operating.

By the operation of the relay 18, the relay contacts 18a and 18b are switched to the b side. That is, the relay contact 18a provided on the battery 20 side disconnects the supply of the battery voltage 12V to the booster circuit 21 by switching to the b side, and is placed in the charging state via the resistor R8 and the diode D5 provided in the charging circuit 19. ing. Again 10
The switching relay contact 18b provided on the V constant voltage circuit 22 side is also b
Since it is closed to the side, DC24V obtained by the 24V constant voltage circuit 34 is input, DC10V is output based on this, and the 5V constant voltage circuit 23 also outputs DC5V based on the output voltage of the 10V constant voltage circuit. ing.

Here, the transistor Q of the power supply switching circuit 16
1 receives the interlock of the transistor Q2 by the control signal E1 of the power supply switching control unit 26 provided in the MPU 24, and has a hysteresis with respect to the change of the power supply voltage E2 obtained from the rectifying and smoothing circuit 15 as shown in FIG. on,
Turned off. The hysteresis characteristic of the transistor Q1 is determined by the control characteristic of the MPU2 of the transistor Q2 shown in FIG.

When the power supply voltage E2 increases, the transistor Q2 is turned on by the control signal E1 of the MPU 24 when it reaches 17V, and is turned off when it exceeds 21V. Therefore, between 17V and 21V, the transistor Q1 is forcibly cut off by turning on the transistor Q2, and when the voltage exceeds 21V, the transistor Q1 turns on. Actually, the MPU 24 performs control to output the control signal E1 so as to turn on the transistor Q2 even when the power supply voltage E2 increases to 24V even at 17V or less, but when the power supply voltage E2 is 17V or less, the zener diode ZD1. Is off, the transistor Q2 operates as shown in FIG.

On the other hand, when the power supply voltage E2 drops,
The transistor Q1 turns off when the voltage of 17 V determined by the Zener diode ZD1 is cut off. That is, only when the input voltage E2 is increased by the transistor Q2, the transistor Q2 is turned on between 17V and 21V to interlock the transistor Q1.

Also in this case, when the power supply voltage E2 drops to 17 V or less, the control signal E1 for turning on the transistor Q2 is about to be output. The reason why the transistor Q1 has such a hysteresis characteristic is that if the transistor Q2 is not provided, the rectifying / smoothing circuit 15 becomes unloaded by switching to the standby power supply when the power supply voltage E2 is below 17V. As the load current becomes substantially zero, the power supply voltage to the power supply switching circuit 16 is temporarily restored and exceeds 17V.

Therefore, the Zener diode ZD1 is turned on again to turn on the transistor Q1 to operate the relay 18 to return the power source to the rectifying / smoothing circuit 15 side. Then, by connecting the load to the rectifying / smoothing circuit 15, the power supply voltage to the power supply switching circuit 16 is cut off 17V again, and switching to the standby power supply is performed. That is, when the interlock by the transistor Q2 is not provided, hunting for switching the power source occurs at the boundary of 17V determined by the Zener diode ZD1.

On the other hand, when the interlock is performed by the transistor Q2, the power supply voltage from the rectifying / smoothing circuit 15 is cut off at 17V, and the transistor Q1 is turned off to switch to the standby power supply side to be in a no-load state. As a result, even if the voltage exceeds 17V again, if it exceeds 17V, an interlock occurs due to the transistor Q2 turning on, and the transistor Q1 does not turn on even when the Zener diode ZD1 conducts, preventing the power supply from returning due to the recovery of the power supply voltage. can do.

Of course, if the power supply switching circuit 16 is desired to have a hysteresis characteristic, it can be realized by a comparator circuit with current feedback instead of the software hysteresis characteristic by the power supply switching control unit 26 of the MPU 24. In this way, switching to the standby power supply side is performed by the restoration of the relay 18 by turning off the transistor Q1 of the power supply switching circuit 16 due to the power failure of the commercial AC 100 V, and the switching relay contact 1
When 8a is switched to the a side as shown in the drawing, the battery voltage DC12V of the battery 20 is input to the booster circuit 21, is boosted to, for example, about 30V, and DC3 via the diode D7.
The voltage is directly supplied to the load side as 0V, and is reduced to 24V DC by the 24V constant voltage circuit 34 and supplied to the load side.

At this time, the standby power supply lamp 28 connected to the output line of the booster circuit 21 is turned on to indicate that the standby power supply has been switched to. Of course, the AC power supply lamp 17 will be turned off. On the other hand, when the switching relay contact 18b is also switched to the side a in the figure, the battery voltage DC12V from the battery 20 is directly supplied to the 10V constant voltage circuit 22 via the switching relay contact 18a which is also switched to the side a, and the load side is connected. DC10V is supplied to. The output of the 10V constant voltage circuit 22 is input to the 5V constant voltage circuit 23 and
The constant voltage circuit 23 supplies DC5V to the load side.

Next, the processing operation by the standby power supply test section 27 provided in the MPU 24 will be described. During the standby power supply test, the standby power supply test switch 25 is turned on. The standby power supply test switch 25 is a non-lock switch, and the standby power supply test is performed while the switch is turned on. When the standby power supply test section 27 of the MPU 24 recognizes the ON operation of the standby power supply test switch 25, the control signal E1
Is output to the transistor Q2 of the power supply switching circuit 16, the transistor Q2 is turned on, the transistor Q1 that has been in the on state until then is forcibly cut off, and the relay 18 is deactivated to switch to the standby power supply.

Subsequently, the backup power supply test section 27 outputs a test signal E3 to the backup power supply test circuit 32, turns on the transistors Q3 and Q4, and sets the dummy resistor R16 to the booster circuit 21.
Of the battery 20 and the booster circuit 21 to supply a specified load current. At this time, power is also supplied to the load side through the diode D7 at the same time, and a preliminary power supply test is performed by flowing a consumption current obtained by adding a dummy load resistor R16 to a normal load. The voltage during the backup power supply test is taken out from the input side of the booster circuit 21 and taken into the MPU 24 as the voltage signal E4. If the voltage is within a predetermined voltage range, the backup power supply is determined to be normal, and the backup power supply test result is obtained. The lamp 29 is turned on. On the other hand, when the capacity of the battery 20 drops and the voltage signal E4 falls below the specified range, the standby power supply test result lamp 29 is turned off to notify the battery capacity drop.

In the embodiment of FIG. 2, the output voltage of the battery 20 is changed to the voltage input circuit 2 during the standby power supply test.
Although the test state is judged by taking in the voltage signal E4 to the MPU 24 according to 3, the DC 24V obtained via the 24V constant voltage circuit 34 is taken into the MPU 24 by using a similar voltage input circuit and monitored. Good. Further, in the above-described embodiment, about half the power supply voltage of the DC power supply circuit is generated by the battery of the auxiliary power supply, but if the voltage of the battery on the auxiliary power supply side is low, Of course, each voltage is not limited to the value shown in the embodiment.

Further, although the fire alarm equipment has been described in the present embodiment, the present invention can be applied to other disaster alarm equipment such as gas.

[0050]

As described above, according to the present invention, the number of directly connected batteries can be reduced by lowering the voltage of the battery used as a standby power source, and the number of batteries when a NiCd battery is used can be reduced. In addition, since the battery characteristics can be easily made uniform, the stability and reliability of the standby power supply can be improved, and even if a booster circuit is newly provided along with the low-voltage battery, the cost of the entire power supply device will be sufficient. Can be lowered.

Further, by reducing the voltage of the standby power supply, it is possible to use a transformer having a simple structure having a single secondary winding tap without the need for providing a winding tap dedicated to charging the battery, which makes the transformer compact. It is possible to realize measurement and cost reduction.
Also, for a backup power supply that combines a low-voltage battery and a booster circuit, a backup power supply test in which a dummy load is connected to the output side of the booster circuit is performed, and a backup power supply test that includes the entire battery and booster circuit can be performed. The backup performance that accompanies the low voltage of the battery can be reliably guaranteed through the backup power supply.

Further, when the standby power source is switched, the output voltage of the battery is directly supplied to the direct current power source circuit of a low voltage equal to or lower than the supply voltage of the low voltage battery provided in the standby power source. By providing a backup power supply bypass supply circuit, a low voltage DC power supply circuit equal to or lower than the battery voltage can be efficiently supplied without receiving power loss due to the booster circuit. Backup performance can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a disaster prevention monitoring system to which the present invention is applied.

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

3 is an explanatory diagram of a hysteresis characteristic of power supply switching by the MPU of FIG.

FIG. 4 is a circuit diagram of a conventional power supply device.

[Explanation of symbols]

 15: Rectifying / smoothing circuit (DC power supply circuit) 16: Power supply switching circuit 17: AC power supply lamp 18: Relays 18a, 18b: Switching relay contacts 19: Charging circuit 20: Battery (standby power supply) 21: Boosting circuit 22: 10V constant voltage Circuit 23: 5V constant voltage circuit 24: MPU 25: Standby power switch 26: Power supply switching control unit 27: Standby power supply test unit 28: Standby power supply light 29: Standby power supply test result light 32: Standby power supply test circuit 33: Voltage input circuit 34: 24V constant voltage circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masashi Arikawa 2-1043 Kamiosaki, Shinagawa-ku, Tokyo Hochiki Co., Ltd.

Claims (4)

[Claims] 1. A power supply device for an alarm receiver which receives a signal from a sensor and outputs an alarm, wherein a commercial AC voltage input via a transformer is rectified and smoothed to load a predetermined DC voltage to a load. A DC power supply circuit to supply, a backup power supply that outputs a DC voltage lower than a predetermined DC voltage output from the DC power supply circuit, and a booster circuit that boosts the output voltage of the backup power supply to about the predetermined voltage of the rectifying and smoothing circuit. A power supply device for an alarm receiver, comprising: a power supply switching circuit that performs backup by switching from the DC power supply circuit to a power supply by the backup power supply and a booster circuit when the AC power supply fails. 2. The alarm receiver power supply device according to claim 1, wherein the transformer has a single secondary winding tap, and the secondary winding tap is input to the DC power supply circuit. A power supply device for an alarm receiver, characterized in that the secondary tap is connected to and input to the charging circuit of the standby power supply. 3. The power supply device for an alarm receiver according to claim 1, further, when the standby power supply test switch is operated, the power supply switching circuit is operated to switch to the standby power supply, and the output of the booster circuit is dummy. A power supply device for an alarm receiver, comprising a standby power supply test circuit connected to a load and testing the standby power supply including the booster circuit. 4. The alarm receiver power supply device according to claim 1, wherein a predetermined voltage of the DC power supply circuit is further adjusted to a specified low voltage lower than an output voltage of the standby power supply and supplied to a load. A spare low-voltage direct-current power supply circuit that directly supplies the output voltage of the standby power supply to the low-voltage direct-current power supply circuit without passing through the booster circuit when the power supply switching circuit switches to the standby power supply. A power supply device for an alarm receiver, which is provided with a power supply bypass supply circuit.