JPH0428194Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a power supply device for fire alarm equipment that has a load circuit consisting of a CPU, memory, etc. The present invention proposes a power supply device that is devised so that stable power is supplied even during switching operations.

(Prior Art) A typical conventional power supply device of this kind, shown in FIG.
The backup power supply AE, which is supplied to the load circuit LC such as a fire monitoring circuit through the constant voltage circuit CV and is charged by the charging circuit CC consisting of the charging resistor R and the diode _D1 , is At times, the power supply can be switched to the load circuit LC by the operation of the power outage monitoring circuit IM, and when the power outage is restored, the power supply is switched to the regular power supply NE again by the operation of the power outage monitoring circuit IM.

This switching operation is performed by switching the output contact im of the power failure monitoring circuit IM, which is in contact with terminal a when supplied by the regular power supply NE, to terminal b.
When the backup power source AE is supplied, the output contact im of the power failure monitoring circuit IM, which is in contact with the terminal b, is switched to the terminal a.

And when there is a momentary interruption during the switching transition period of the output contact im,
This configuration is such that power is supplied to the load circuit LC by discharging a capacitor C that is charged in a steady state.

(Problem that the invention attempts to solve) In the above conventional equipment, the regular power supply NE and standby power supply
Since the switching between the AE and the AE is performed only by detecting the output from the power failure monitoring circuit IM, there is no problem in the event of a power outage because the switching occurs immediately.

However, when a power outage is restored, the output voltage of the constant voltage circuit CV does not stabilize immediately, and there is a slight delay until it reaches the predetermined voltage. Output contact im returns to terminal a on the NE side of the regular power supply, and the load circuit LC returns to the regular power supply via the constant voltage circuit CV.
If connected to the NE, unstable power will be supplied to the load circuit LC, making it impossible to immediately supply the rated operating voltage to the CPU, etc. that make up the load circuit LC, and the fire monitoring circuit, which is the load circuit LC, etc. There is a risk that a malfunction may occur, for example, a fire display that has been maintained in operation may be restored.

As a countermeasure for such problems during power outage recovery, there is a special technology that constantly compares the output voltage of the regular power source and the output voltage of the backup power source, and switches between the regular power source and the backup power source based on the results. 1977-
No. 16931.

According to this technology, when a power outage is restored, switching to the regular power supply is performed when the output voltage of the constant voltage circuit of the regular power supply stabilizes and reaches a predetermined value, which is convenient. The output voltage of the converter does not suddenly drop immediately, and therefore the switching to the standby power supply is not performed immediately.Therefore, there is a problem that the voltage continues to drop and remains unstable for some time.

In addition, technology that ensures a stable power supply when switching to a backup power source during a power outage was developed in 1982.
This is disclosed in No. 161550, but in order to eliminate the delay in detection during a power outage, switching to the standby power source is performed by both the power outage detection operation and the low voltage output on the load side. This is a technology that only solves the problem of switching to backup power during a power outage.

(Means for solving the problem) In this invention, in the event of a power outage, the output voltage of the constant voltage circuit does not drop immediately, and the switching to the backup power source does not occur immediately, so the voltage remains unstable for a while. The purpose of this project is to solve the conventional problem of ensuring stable power supply switching when power is restored after a power outage, and its configuration is to constantly supply power to the load circuit LC via the constant voltage circuit CV. Standby power supply AE that supplies power to the power supply NE and load circuit LC in the event of a power outage of the regular power supply NE
and a power failure monitoring circuit IM that is connected to the input side of the constant voltage circuit CV and detects the presence or absence of a power failure in the regular power supply NE.
and a voltage detection circuit VD connected to the output side of the constant voltage circuit CV to detect a predetermined voltage of the constant voltage circuit CV.
In the event of a power outage of the regular power supply NE, the power outage monitoring circuit IM
Due to the power outage detection operation, the regular power supply NE switches to the standby power supply AE, and when the regular power supply NE recovers from a power outage,
It is characterized by comprising a switching means M that switches from the standby power source AE to the regular power source NE by the AND output of the power failure recovery detection operation of the power failure monitoring circuit IM and the predetermined voltage detection operation of the voltage detection circuit VD. It is.

(Function) In the event of a power outage in the regular power supply NE, the power outage detection operation of the power outage monitoring circuit IM, which detects the presence or absence of a power outage, is performed, and when the power outage is restored, the power outage recovery detection operation of the power outage monitoring circuit IM and the constant voltage circuit CV are activated. The power supply is switched between the regular power supply NE and the standby power supply AE by the AND output with the predetermined voltage detection operation of the voltage detection circuit VD, which detects the predetermined voltage of the voltage detection circuit VD. Switching is done using the regular power supply.
The above-mentioned conventional problem is that the power outage monitoring circuit IM that detects a power outage in the NE immediately performs the switchover to the standby power source, causing a slight delay in switching over to the standby power source, causing the voltage to remain unstable for a while. This problem has now been resolved, and a stable voltage supply can now be maintained even at the moment of a power outage.

In addition, switching to the regular power supply NE at the time of power failure recovery is performed by ANDing the power failure recovery detection operation of the power failure monitoring circuit IM and the predetermined voltage detection operation of the voltage detection circuit VD.
The output restores the power outage and restores the constant voltage circuit.
This is done when the output voltage of the CV reaches a predetermined value and becomes stable, thus preventing accidents such as the load circuit LC malfunctioning due to voltage drop.

(Embodiment) Next, an embodiment of this invention will be described based on a power supply device having the circuit configuration illustrated in FIG.

The regular power supply NE obtained by rectifying the current of the AC power supply G with the rectifier circuit RC is supplied to the fire monitoring circuit, etc., which is the load circuit LC, via the constant voltage circuit CV, and is also supplied from the charging resistor R and the diode _D1 . The standby power supply AE is being charged by the charging circuit CC.
During a power outage of the regular power supply NE, the power is switched to the load circuit LC by the power outage detection operation of the power outage monitoring circuit IM, and when the power outage is restored,
The configuration is such that the power supply is switched back to the regular power source NE by the AND output of the power failure recovery detection operation of the power failure monitoring circuit IM and the predetermined voltage detection operation of the voltage detection circuit VD.

The predetermined output voltage of the constant voltage circuit CV is determined by the voltage detection circuit VD connected to the output side of the constant voltage circuit CV.
The presence or absence of a power outage in the regular power supply NE is detected by the power outage monitoring circuit IM connected to the input side of the constant voltage circuit CV, and the voltage detection circuit VD
The output is supplied to the switch SW of the switching means M via the output contact im of the power failure monitoring circuit IM.

The power outage monitoring circuit IM is a constant voltage circuit that detects the output voltage of the regular power supply NE, its output contact im contacts the terminal c, and is detected by the voltage detection circuit VD.
When the output voltage of the CV is above a predetermined value (a value that allows the load circuit LC to operate accurately), the switching contact SW contacts the terminal a on the constant voltage circuit CV side by the action of the switch SW. Contrary to the voltage detection circuit
When the output voltage of VD is below the specified value,
The switching means M is configured such that the switching contact sw contacts the terminal b on the standby power supply AE side.

The switching contact sw is connected to the load circuit LC and the capacitor C via a diode _D2 .

Next, the operation of the above embodiment will be explained.

Under normal conditions (when there is no power outage), the output contact im of the power outage monitoring circuit IM contacts terminal c, and when the output voltage of the constant voltage circuit CV detected by the voltage detection circuit VD is stable at a predetermined value, the voltage is detected. The circuit VD turns on and its switch SW changes the switching contact SW to a constant voltage circuit.
It is held in contact with terminal a on the CV side, and a stable voltage is supplied from the constant voltage circuit CV to the load circuit LC.

Simultaneously with this supply operation, the backup power supply AE is charged by the charging circuit CC, and the capacitor C is also charged.

On the other hand, when the regular power supply NE has a power outage, the power outage monitoring circuit IM operates to detect a power outage and the output contact im is opened, and the voltage detection circuit VD operates to turn off and the switch SW connects its switching contact SW from terminal a. Switch to terminal b on the standby power supply AE side.

At the moment of momentary interruption during this switching transition period, that is, the switching contact SW
During the off-time from when the capacitor C leaves the terminal a until it comes into contact with the terminal b, the charge of the capacitor C is supplied to the load circuit LC, so that the load circuit LC can operate normally even during the instantaneous interruption.

Then, when the above switching operation to terminal b is completed,
Power is supplied from the standby power supply AE to the load circuit LC.

In addition, when a power outage occurs, the output voltage of the constant voltage circuit CV does not drop immediately and becomes unstable, so there is a slight delay in turning off the voltage detection circuit VD, but the power outage monitoring circuit IM is activated as soon as the power outage occurs. The above switching contact SW is activated and the load circuit is switched immediately.
Voltage supply from the standby power supply AE to the LC is started.

In this way, the switch to the standby power source AE is performed immediately in the event of a power outage, so the above-mentioned conventional problem in which the voltage is unstable for a while due to a slight delay in switching to the standby power source is resolved. A stable voltage supply can now be maintained even during a power outage.

Further, by immediately switching the switching contact SW, it is possible to prevent backflow from the capacitor C from the time of power failure until the switching contact SW is switched.

When switching contact SW switches, capacitor C
If the voltage of the diode is higher than the voltage of the standby power supply AE, the load on the capacitor C will reverse current.
D ₂ prevents the accident, which causes a large discharge current to flow and burn out this switching contact SW.
Prevented.

Next, when the power outage is restored, the power outage monitoring circuit IM operates immediately and the output contact im immediately contacts terminal c, but the output voltage of the constant voltage circuit CV does not reach the predetermined value immediately, so the voltage detection circuit VD remains off, switch SW does not operate, switching contact
SW remains in contact with terminal b on the standby power supply AE side, and power continues to be supplied from the standby power supply AE.

Then, when the constant voltage circuit CV becomes stable and its output voltage reaches a predetermined value, the voltage detection circuit
VD is turned on and the switch SW operates, and its switching contact SW is switched to terminal a on the constant voltage circuit CV side, but even during this off period, the capacitor C
Power is supplied to the load circuit LC from the terminal a, and after contacting the terminal a, power is again supplied from the regular power supply NE via the constant voltage circuit CV.

As a result, as in the past, when a power outage is restored, unstable power is supplied and the rated operating voltage cannot be immediately supplied to the CPU, etc. that make up the load circuit LC, and the fire monitoring circuit, etc. that is the load circuit LC, may malfunction. We were able to prevent accidents such as accidents occurring.

Therefore, a stable power supply is always ensured, both at the moment of a power outage and when the power is restored.
It has become possible to sufficiently prevent malfunctions of the load circuit LC.

In addition, diode _D2 is connected to the standby power supply AE due to a power outage.
This prevents reverse current from the capacitor C when switching to the normal power supply NE side and when switching to the normal power supply NE side due to recovery from a power outage.

The switching means M may be a known one having the same function as in the above embodiment, for example, a relay may be used as the switch SW, and its contacts may be used as the switching contacts SW.

(Effects of the invention) The power supply device for fire alarm equipment according to this invention is configured as described above, and is connected to the regular power supply NE.
When a power outage occurs, the power failure detection operation of the power failure monitoring circuit IM detects the presence or absence of a power outage, and when the power is restored, the power failure recovery detection operation of the power failure monitoring circuit IM and the predetermined voltage of the constant voltage circuit CV are detected. The power supply is switched between the regular power supply NE and the standby power supply AE by the AND output with the predetermined voltage detection operation of the voltage detection circuit VD. The above-mentioned conventional problem is that the power outage monitoring circuit IM detects a power outage in the NE, and the power outage monitoring circuit IM immediately detects the power outage, causing a slight delay in switching to the standby power supply, causing the voltage to remain unstable for a while. This problem has now been resolved, and a stable voltage supply can now be maintained even at the moment of a power outage.

In addition, switching to the regular power supply NE at the time of power failure recovery is performed by ANDing the power failure recovery detection operation of the power failure monitoring circuit IM and the predetermined voltage detection operation of the voltage detection circuit VD.
The output restores the power outage and restores the constant voltage circuit.
This is done when the output voltage of the CV reaches a predetermined value and becomes stable, thus preventing accidents such as the load circuit LC malfunctioning due to voltage drop.

As a result, a stable power supply is always ensured both at the moment of a power outage and when the power is restored, and malfunctions of the load circuit LC can be sufficiently prevented.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of this invention.
FIG. 2 is a circuit diagram showing a conventional example. CV...constant voltage circuit, LC...load circuit, NE...
...common power supply, AE...standby power supply, IM...power failure monitoring circuit, VD...voltage detection circuit, M...switching means.

Claims (1)

[Scope of utility model registration request] A regular power supply that always supplies power to the load circuit via a constant voltage circuit, a standby power supply that supplies power to the load circuit in the event of a power outage in the regular power supply, and a standby power supply that is connected to the input side of the constant voltage circuit in case of a power outage in the regular power supply. A power outage monitoring circuit detects the presence or absence of a power outage, a voltage detection circuit is connected to the output side of the constant voltage circuit and detects a predetermined voltage of the constant voltage circuit, and in the event of a power outage, the power outage detection circuit detects the presence of a power outage. a switching means for switching from the power supply to the standby power supply and, when the power supply is restored from a power outage, from the standby power supply to the common power supply by an AND output of the power failure recovery detection operation of the power failure monitoring circuit and the predetermined voltage detection operation of the voltage detection circuit; A power supply device for fire alarm equipment, characterized by comprising: