JPH0353574Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of an emergency lighting device that lights up an emergency lighting lamp (emergency lighting load) with a rated voltage of about several volts when the commercial power supply is cut off.

This type of emergency lighting device uses a battery with a relatively small capacity that is normally charged with a commercial power source. In addition, in order to prevent the above lamp from not lighting up in an emergency due to a drop in battery voltage, many devices have a monitor for battery monitoring.
LED is installed. However, in conventional emergency lighting devices, since the monitor LED was driven by the battery itself, there was an inconvenience that if the battery voltage decreased below the forward drop voltage of the monitor LED, it could not be detected. It is also monitored by the degree of battery voltage drop.
The brightness of the LED fluctuates, and even on a normal monitor
Since the forward voltage drop of an LED is relatively large, approximately 1.7 to 2.2V, accurate monitoring of battery voltage has not been possible.

The purpose of this invention is to eliminate the above-mentioned drawbacks, to enable more accurate monitoring of the battery voltage drop, and to monitor the battery voltage as well as to monitor the battery voltage using a single monitor LED. To provide an emergency lighting device which can monitor whether or not a commercial voltage lamp or a low voltage lamp is disconnected, and can surely prevent wasteful consumption of battery voltage.

Hereinafter, embodiments of this invention will be described with reference to the drawings.

The figure is a circuit diagram of an emergency lighting device that is an embodiment of this invention. A commercial voltage 1 is stepped down to about several volts by a step-down transformer 2, converted to direct current by a diode bridge 3, and supplied to both terminals a and b of a battery B. In addition, the commercial voltage 1 is an emergency lamp L connected in series to the primary side of another current transformer 4.
Turn on 1. The secondary side of the current transformer 4 is converted into a direct current by a diode D1 and a capacitor C1, and is led to a second switch circuit, which will be described later.

The lamps L2 and L3, which are low-voltage loads, have a rated voltage set to about 2.5V, and are turned on by receiving the DC voltage from the battery B. This lamp L2,
A first switch circuit SW1 is connected in series to L3, and when this switch circuit SW1 is turned on, the light is turned on by the voltage of the battery B. The first switch circuit SW1 includes transistors TR1 and TR1, which directly turn on and off the lamps L2 and L3, respectively.
It consists of a transistor TR2, and a transistor TR3 that controls on/off of these transistors TR1 and TR2. The base of the transistor TR3 is connected to the step-down transformer 2 through diodes D2 and D3.
The next output voltage is applied, and the emitter has a resistor R1.
Since the output voltage of the diode bridge 3 is applied through the transistor TR3, the transistor TR3 is normally off, and turns on when the commercial voltage is interrupted. When transistor TR3 is turned on, transistors TR1 and TR2 are also turned on, and battery B lights up lamps L2 and L3. Also transistor
When TR3 is in the off state, the transistor
Since TR1 and TR2 are also off, the lamp L2,
Leave L3 in the off state.

The monitor LED D4, which lights up when any of the lamps L1 to L3 is disconnected or when the voltage of the battery B drops below a certain level, lights up upon receiving the secondary output of the step-down transformer 2. A second switch circuit SW2 is connected in series to the monitor LED D4. This second switch circuit SW2 includes a transistor TR4 that directly turns on and off the monitor LED D4, and transistors TR5 to TR that are OR-connected to the base of the transistor TR4 via diodes D5 to D7.
It consists of 7. Transistor TR4 receives the secondary side output of step-down transformer 2 and turns on when any one of transistors TR5 to TR7 turns off, and turns off when all of the transistors TR5 to TR7 turn on. Also transistor
TR5 is turned off when lamp L3 is disconnected, transistor TR6 is turned off when lamp L2 is disconnected,
Transistor TR7 is turned off when lamp L1 is disconnected. Therefore, if any of the lamps L1 to L3 is disconnected, transistor TR4 turns on,
The monitor LED D4 is turned on by the secondary output of the step-down transformer 2.

The voltage across the battery B is detected by a known battery voltage detection section 5. An input side diode D8 of the photocoupler PC is connected to the output side of the battery voltage detection section 5, and when the voltage across the battery B decreases, the battery B drives the diode D8. Generally, due to the characteristics of a photocoupler, the forward voltage drop VF of the diode D8 is relatively small compared to a normal diode. Photocoupler
The output of PC is connected to the base of transistor TR4 of second switch circuit SW2, and turns on transistor TR4 when photocoupler PC is driven. When the transistor TR4 is turned on, the monitor LED D4 receives the secondary output of the step-down transformer 2 and lights up as described above.
Therefore, the switch circuit SW2 switches the lamps L1 to
When one of L3 is disconnected, or when the voltage of battery B drops below a certain voltage specified by battery detection section 5, step-down transformer 2
It will light up in response to the secondary side output of.

In addition, the battery voltage is normally 2.4V.
, and the forward drop voltage VF of the diode D8 on the input side of the photocoupler PC is about 1.2V.
Therefore, the voltage of battery B changes from 2.4V to 1.5V.
Even if the power decreases to a certain degree, it is possible to sufficiently drive the photocoupler PC. This means that even if the number of cells in battery B is small, that is, a small battery can be used.

In the emergency lighting device having the above configuration, when the commercial voltage 1 is normally supplied, the first switch circuit SW1 is in the OFF state, and the lamp L
2, L3 is turned off and battery B is being charged. In this state, lamps L1 to L3
When one of them is disconnected, one of the transistors TR5 to TR7 of the second switch circuit SW2 detects the disconnection and turns on the transistor TR4. This lights up the monitor LED, D4,
Notifies the outside that the lamp is burnt out. On the other hand, when the commercial voltage 1 is cut off, the transistor TR3 of the first switch circuit SW detects this state, and the transistor TR
Lamp L by turning on TR1 and TR2.
2 and L3 are turned on by battery B. Furthermore, when commercial voltage 1 is being supplied normally,
When the battery voltage detection section 5 detects that the voltage of the battery B has decreased below a certain level due to some reason, it drives the photocoupler PC to turn on the transistor TR4 of the second switch circuit SW2.
As a result, the monitor LED D4 lights up, and the voltage drop in the battery B is notified to the outside. Further, the monitor LED D4 is normally used for testing the battery B. That is, the commercial power supply is turned off during regular inspections, the power supply is turned on again after a certain period of time, and at that time it is checked whether the monitor LED, D4, is lit. If the light is on, assume that the voltage drop in the battery is large and replace it. If it is not lit, it is determined that the battery is normal. When performing such a test, the voltage of the battery B is applied only to the battery voltage detection section 5 when the power is off, and the voltage of the battery B is applied to the second switch circuit SW2.
Since it is not used as a driving voltage, the possibility that the LED, D8, will be turned off due to discharge during the process is extremely small. Moreover,
Since the forward voltage drop of LED D8 is small compared to that of an ordinary diode, such a possibility (the possibility that LED D8 turns off) is further reduced. This means that even if the battery B is small, it can be tested accurately. In this way, the monitor LED, D4,
It is possible to monitor whether the lamps L1 to L3 are disconnected or not, and to monitor the voltage of the battery B while the commercial voltage is being normally supplied. In the function of monitoring the voltage drop of battery B, even when the voltage of battery B drops significantly and the commercial voltage 1 is restored, the forward voltage drop of diode D8 on the input side of photocoupler PC is small. The voltage drop state can be notified externally almost reliably, and reliability is extremely high. Furthermore, since the monitor LED D4 is lit by the secondary output of the step-down transformer 2, its brightness remains constant regardless of the degree of voltage drop in the battery B. Furthermore, since the monitor LED D4 is not lit by the power of the battery B, unnecessary consumption of the battery B can be prevented, and repairs such as battery replacement can be made easier.

As mentioned above, according to this idea, one monitor
Since it is possible to monitor a disconnection state of a low voltage lamp or a commercial voltage lamp and a voltage drop state of a low voltage battery using an LED, the cost is low, and a battery voltage detection unit that detects a voltage drop of battery B; Since the drive section of the monitor LED is necessarily electrically isolated by the photocoupler PC, the first switch circuit that detects disconnection of the low voltage load and the battery voltage detection section are automatically connected. This has the advantage that the circuit configuration of the second switch circuit SW2 is very simple. In addition, the monitor LED is driven by the voltage drop of the commercial voltage, and when the battery voltage drops, the LED is driven by the battery's own voltage.
Since the primary side input of the photocoupler has a lower forward voltage drop than that of a normal LED, the brightness of the monitor LED remains constant regardless of the degree of battery voltage drop, and the degree of voltage drop of battery B can be compared. Even if the target is large, the condition can be reported almost reliably.

[Brief explanation of drawings]

The figure is a circuit diagram of an emergency lighting device that is an embodiment of this invention. 1...Commercial voltage, 2...Step-down transformer, 5...
Battery voltage detection section, SW1...first switch circuit, SW2...second switch circuit, D4...
Monitor LED, PC...Photocoupler, B...Battery.

Claims (1)

[Scope of utility model registration request] A low-voltage battery that is normally charged, a step-down transformer that steps down the commercial voltage, a first rectifier circuit that rectifies the secondary output voltage of the step-down transformer and supplies charging current to the low-voltage battery, and a step-down transformer that steps down the commercial voltage. a low-voltage lamp driven by a voltage battery; a first switch circuit connected in series with the low-voltage lamp and supplying the voltage of the battery to the low-voltage lamp when the commercial voltage is interrupted; A commercial voltage lamp and a monitor LED connected in series with the current transformer; a battery voltage detection circuit that drives a photocoupler when the voltage of the battery drops below a certain level; The drive voltage is monitored when the current transformer is disconnected, the secondary output of the current transformer is reduced, or the photocoupler is driven.
It is characterized by comprising a second switch circuit that supplies the LED, and a second rectifier circuit that rectifies the secondary output voltage of the step-down transformer and supplies the drive voltage to the second switch circuit. Emergency lighting device.