JPH0311834Y2 - - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a discharge lamp lighting device.

To light a discharge lamp, in addition to a lighting circuit using commercial power, a high-frequency inverter whose power source is a battery that is charged by commercial power is prepared, and the discharge lamp is lit by selectively using the commercial power and the high-frequency inverter. Such a configuration is widely used, for example, for lighting emergency lights or guide lights.

Figure 1 shows a circuit diagram of a conventional example, where 1 is a commercial AC power supply, 2 is a lighting switch, 3 is a switch coil,
4 is a discharge lamp, 5 is a glow lamp, 6 is a check switch, 7 is a step-down transformer, 8 is a full-wave rectifier, 9 is a relay, 10 is a battery, 11 is a switch element such as a transistor, 12 is a high frequency inverter, 13
is its transistor, and 14 is an oscillation transformer.

The inspection switch 6 is always on, and the relay 9 is energized and its contacts 9a,
9b is turned on at the normally open contact side. Further, the battery 10 is charged by the output of the full-wave rectifier 8. Furthermore, a capacitor 16 is connected via a diode 15.
Since the transistor 17 is charged, the transistor 17 is turned off, and therefore the switch 11 is turned off, so that the high frequency inverter 12 is cut off from the battery 10 and is in a non-oscillating state.

If the lighting switch 2 is turned on at this point, the filament of the discharge lamp 4 will open the normally open contacts 9a and 9b. The discharge lamp 4 is preheated via the glow switch 5, and then the discharge lamp 4 is turned on by turning off the glow switch 5.

Further, when the commercial power supply 1 is cut off, or when the inspection switch 6 is turned off and the relay 9 is de-energized, the contacts 9a and 9b are turned on to the normally closed contact side. At the same time, charging of the capacitor 16 also stops, so
When the terminal voltage decreases and reaches a certain value, transistor 17 is turned on, so transistor 11 is also turned on, and high frequency inverter 12 is connected to battery 10 to start oscillation. As a result, the discharge lamp 4 is lit by the output of the oscillation transformer 14.

On the other hand, when the transistor 11 is turned on, the voltage of the battery 10 is applied to both ends of the series circuit of the capacitor 18 and the resistor 19. Until then, capacitor 1
Since resistor 8 is not charged, a voltage is generated across resistor 19. This voltage is applied via diode 20 to battery voltage detector 21 to reset it. This battery voltage detector 21 has a battery 10
After being reset as described above, the voltage of the battery 10 is detected, and when it is detected that it is below the specified value, the indicator lamp (light emitting diode) 22 is turned on.

The voltage across the resistor 19 decreases as the capacitor 18 is charged, and disappears upon completion of charging. In other words, the above-mentioned reset only takes place for a short time when transistor 11 is turned on.

Next, when the commercial power supply is restored or the inspection switch 6 is turned off, the transistor 11 is turned off, and the discharge lamp 4 is connected to the commercial power supply through the above-described process.
It is lit by.

At this time, the capacitor 18 should be discharged via the discharge resistor 23, but the transistor 1
From 1, high frequency inverter 12 and capacitor 18
In this conventional circuit, a portion of the discharge current of the capacitor 18 flows into the base of the transistor 13 of the high frequency inverter 12 as a base current. Therefore, originally, by turning off the transistor 11, the high frequency inverter 1
2 should stop its oscillation, but its oscillation continues.

The purpose of this invention is to reliably prevent the high frequency inverter from continuing to oscillate by discharging a capacitor to provide a reset signal to the battery voltage detector when lighting is started using a commercial power source.

An embodiment of this invention will be explained with reference to FIG.
Note that parts given the same reference numerals as in FIG. 1 indicate the same or corresponding parts. As understood from the configuration of FIG. 2, in this invention, the capacitor 18 is connected in series with
A diode 24 is connected to prevent the reverse flow of the discharge current of the capacitor 18.

According to the above configuration, when the commercial power supply 1 is restored or the check switch 6 is turned on, the transistor 11 is turned off and charging of the capacitor 18 is stopped, the discharge current of the capacitor 18 is transferred to the diode. 24 prevents it from flowing to the high frequency inverter 12 side. Therefore, the high frequency inverter 12 which has stopped oscillating by turning off the transistor 11 continues to stop oscillating, and the continuation of oscillation as in the conventional case can be reliably prevented.

As detailed above, according to this invention, the continuation of oscillation of the high frequency inverter due to the reverse flow of the capacitor provided for resetting the battery voltage detector can be reliably ensured by the simple configuration of simply inserting a diode. If it can be avoided, it will have a great effect.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional example, and FIG. 2 is a circuit diagram showing an embodiment of this invention. 1... Commercial power supply, 4... Discharge lamp, 10... Battery, 11... Switch element, 12... High frequency inverter, 18... Capacitor, 19... Resistor, 2
1...Battery voltage detection circuit, 22...Indicator light, 23
...Discharge resistance, 24...Diode.

Claims (1)

[Scope of utility model registration request] A switch that is connected between a battery that is charged based on a commercial power supply and a high-frequency inverter and the battery and a high-frequency inverter, and that is turned on when the commercial power supply is cut off and causes the high-frequency inverter to operate in oscillation using the battery as an operating power supply. a discharge lamp that is normally lit by the commercial power supply and lit by its oscillation output when the high-frequency inverter operates in oscillation; and a discharge lamp that is lit by the oscillation output of the high-frequency inverter when the switch element is turned on, and a diode that is lit by the battery when the switch element is turned on. A series circuit of a capacitor and a resistor that starts to be charged through the capacitor, and a voltage across the resistor until the capacitor is fully charged is given as a reset signal, and a battery for lighting an indicator light when the battery is below a standard value. A discharge lamp lighting device comprising a voltage detection circuit and a discharge resistor that discharges the capacitor when the switch element is turned off.