JPS58192294A - Device for firing fluorescent lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lighting device for a fluorescent lamp used for night lighting indoors and outdoors.

Generally, this type of fluorescent lamp lighting device causes an oscillation transistor to oscillate when a switch is turned on, and this oscillation generates a high voltage on the secondary side of the oscillation transformer, which lights the fluorescent tube. However, when a battery is used as a power source for the lighting device of this fluorescent lamp, the voltage fluctuation of this battery is much larger than that of a household 5G10oV power supply, so the lighting device is adjusted to correspond to this voltage fluctuation. There has never been a device equipped with a current control circuit and a protection circuit against heat generation of the oscillation transistor.

In view of the above points, the present invention has been developed to increase the lighting current of a fluorescent lamp when a battery is used as a power source even when the battery voltage is low, and to increase the lighting current of a fluorescent lamp when the battery voltage is high or when the ambient temperature rises. An object of the present invention is to provide a lighting device for a fluorescent lamp that can suppress the lighting current and lower the temperature of the heat sink when the temperature of the heat sink increases.

The basic configuration of the present invention to achieve the above object is that the collector of the lighting current control transistor is connected to the base resistance of the oscillating T transistor, and the collector of the lighting current control transistor is connected to the emitter of the lighting current control transistor. ] The emitter resistor is connected to the positive side of the battery power source, and a temperature and voltage reduction compensation diode is further connected between the positive side of the battery power source and the base of the lighting current control transistor.

The present invention has the above configuration, so that even when a battery is used as a power source, even when the battery voltage is low, the temperature and the effect of the voltage reduction compensation diode are such that the positive side of the battery power source and the pace of the lighting current control transistor are connected to each other. The voltage becomes almost constant, and as a result, a large lighting current flows, making it easier to light the fluorescent tube.Also, when the battery voltage is high or the ambient temperature rises, the temperature of the heat sink of the oscillation transistor decreases to - When F rises, the base current of the oscillation transistor can be reduced and the lighting current can be reduced due to the effect of the emitter resistance of the lighting current control transistor or the effect of the temperature and voltage reduction compensation diode, so that the oscillation is stopped. It has various excellent features such as being able to lower the temperature of the heat sink of the transistor, and as a result, preventing thermal runaway damage to the oscillating transistor.

An embodiment of the present invention will be described below with reference to the accompanying drawings. In Figure 1, 1 is the battery power source of the car,
It is powered by a DC 12v battery. 2 is an on-off switch connected to the positive side of battery power supply 1, 3 is battery power supply 1
The electrolytic capacitor 3 is connected in parallel with the battery power source 1. The electrolytic capacitor 3 is provided to reduce the internal impedance of the battery power source 1. 4 is an oscillation transistor,
Reference numeral 6 denotes a lighting current control transistor, and this lighting current control transistor 5 uses the base resistor 6 of the oscillation transistor 4 as a collector resistance. 57.8 is a capacitor connected in series to the pace resistor 6 of the oscillation transistor 4. The connection point of this capacitor 7.8 is connected to the emitter of the oscillation transistor 4. 9,10,11.1
2.13 are windings wound around the same ferrite core, and constitute the oscillation transformers 1 and 4. This oscillation transformer 140 primary winding 1Q and the oscillation transformer 14
(One filament of the fluorescent tube 16 on the secondary side) The filament preheating windings 13 and 6·-1 for preheating 151L are electrically connected, and these are connected to the negative side of the battery power source 1. The other filament 15b of the fluorescent tube 15 is connected to the filament pre-heat winding 11 on the secondary side of the oscillation transformer 14. 16 is a capacitor connected in parallel with the high voltage winding 12 on the secondary side of the oscillation transformer 14; 17 is a fluorescent tube current control connected between one of the capacitors 16 and one of the filament preheating windings 11; It is a capacitor for 18 is a diode connected between the filament preheating winding 13 and one filament 16a of the fluorescent tube 16; the anode side of this diode 18 is located on the negative side of the battery power source 1, and the cathode side is located on the fluorescent tube side. 15) are connected so as to be located on the 15a side.

A pace resistor 19 is connected to the base of the lighting current control transistor 6, and this pace resistor 19 is connected to the cathode side of the diode 18, and the collector is connected to the pace resistor 6 through the primary winding 9. It is connected to the base of the oscillation transistor 4.

Reference numeral 20 denotes a metal reflecting plate, which is connected to the negative side of the battery power source 1 so as to serve as a nearby conductor.

One end of the emitter resistor 21 is still connected to the emitter of the lighting current control transistor 6, and the emitter resistor 2
The other end of 1 is connected to the positive side of battery power supply 1. Furthermore, a temperature and voltage reduction compensation diode 22 is connected between the base of the lighting current control transistor 50 and the positive side of the battery power supply 1.

The operation in the above configuration will be explained. When lighting the fluorescent tube 15, when the switch 2 is turned on, the base current of the lighting current control transistor 6 passes through the pace resistor 19, one filament 15a1 of the fluorescent tube 15, and the filament preheating winding 13 to the battery power source. Since the current flows to the negative side of 1, the lighting current control transistor 6 is turned on. When turned on, the oscillation transistor 4 is also turned on via the pace resistor 6 to perform blocking oscillation, and this oscillation generates a high voltage on the secondary side of the oscillation transformer 14, which lights up the fluorescent tube 16.

When lighting the fluorescent tube 16 described above, when the voltage of the battery power supply 1 is low, the voltage between the positive side of the battery power supply 1 and the base of the lighting current control transistor 50 decreases, so that the voltage flows to the lighting current control transistor 5. Base current (
The lighting current (lighting current) also decreases, and as a result, the fluorescent tube 16 cannot be lit smoothly. However, in one embodiment of the present invention, there is a Since the temperature and voltage drop compensation diode 22 is connected to
Due to the zero effect, even when the voltage of the battery power source 1 is low, the voltage between the positive side of the battery power source 1 and the pace of the lighting current control transistor 5 can be kept almost constant. The current is larger than in the case without the temperature and voltage drop compensation diode 22, and as a result, the fluorescent tube 150 can be easily lit.

Furthermore, when the voltage of the battery power supply 1 is high, the lighting tends to be heavier, but since the emitter resistor 21 is connected to the emitter of the lighting current control transistor 6, this emitter resistor 21 is the lighting current controlling transistor. It works to lower the N pressure between the emitter and base of 6. Furthermore, when the ambient temperature rises and the seismic intensity of the heat sink of the oscillation transistor 4 rises, the temperature located in the vicinity and the temperature of the voltage reduction compensation diode 22 also rise.
Temperature and reduced voltage compensation diode 2 as shown in the figure.
As a result, the emitter-pace voltage of the lighting current control transistor 6 decreases, and the base current of the oscillation transistor 4 also decreases, so the temperature of the heat sink of the oscillation transistor 4 decreases. can be lowered. Thereby, the oscillation transistor 4 can be protected from thermal runaway destruction. Furthermore, the base resistor 19 of the lighting current control transistor 6 is connected to the fluorescent tube 16.
filament preheating winding 1 on the secondary side of the oscillation transformer 14
Since it is connected to the negative side of the battery power supply 1 through the terminal 3, the lighting current can be completely cut off when the fluorescent tube 15 is not attached, making it extremely safe.

As described above, according to the present invention, the collector of the lighting current control transistor is connected to the base resistance of the oscillation transistor, and the emitter resistor connected to the emitter of the lighting current control transistor is connected to the positive side of the battery power supply. Furthermore, since a temperature and reduced voltage compensation diode is connected between the positive side of the battery power supply and the base of the lighting current control transistor, the temperature and reduced voltage compensation diode is connected even when the battery voltage is low. As a result, the voltage between the positive side of the battery power supply and the base of the lighting current control transistor becomes almost constant, and as a result, the lighting current increases, making it easier to light the fluorescent tube. When the ambient temperature rises and the temperature of the heat sink of the oscillation transistor increases, the base current of the oscillation transistor is reduced by the emitter resistance of the lighting current control transistor or the temperature and voltage reduction compensation diode. Moreover, since the lighting current can be reduced, the temperature of the heat sink of the oscillation transistor can also be lowered, and as a result, thermal runaway destruction of the oscillation transistor can be prevented. be.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a lighting device for a fluorescent lamp according to an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between temperature and voltage drop of a diode for compensating for reduced voltage in the same lighting device. 1...Battery power supply, 2...Switch, 4
...Oscillation transistor, 5 ...Lighting current control transistor, 6 ...Base resistor, 14
...Oscillation transformer, 16...Fluorescent tube, 21
... Emitter resistance, 22 ... Temperature and reduced voltage compensation diode.

Claims (1)

[Claims] In a fluorescent lamp lighting device that causes an oscillation transistor to oscillate when a switch is turned on, this oscillation generates a high voltage on the secondary side of an oscillation transformer, and this high voltage lights a fluorescent tube. The collector of the lighting current control transistor is connected to the resistor, and the emitter resistor connected to the emitter of the lighting current control transistor is connected to the positive side of the battery power source, and the positive side of the battery power source and the lighting current control transistor are connected to the resistor. A lighting device for a fluorescent lamp with a temperature and voltage reduction compensation diode connected between the base and the base.