JPH06104091A - Fluorescent lamp lighting device - Google Patents

Abstract

PURPOSE:To surely start a fluorescent lamp in an electronic starter type fluorescent lamp lighting device even at a low temperature or low power source voltage. CONSTITUTION:A fluorescent lamp lighting device is provided with a series body of a ballast 2 connected to an AC power source 1 and a fluorescent lamp 3 having a pair of preheating electrodes. A series body of a diode 5 and the collector and emitter of a transistor 13 is connected between the non-power source side preheating electrodes of the fluorescent lamp 3, a series body of a resistor 11 and a thyristor 10 for carrying a current to the base is connected between the collector and emitter of the transistor 13, and the capacitor 8 of a timer circuit is connected to the gate circuit of the thyristor 10. A lighting judging means consisting of a resistance dividing means for judging the lighting and non-lighting of the fluorescent lamp 3 by detecting the voltage between the preheating electrodes is connected between the non-power source side preheating electrodes, and a transistor 20 for reducing the potential of the capacitor 8 by operating the fluorescent lamp 3 by the voltage resistance-divided by the lighting judging means, when the fluorescent lamp 3, is not lighted is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp lighting device, and more particularly to a fluorescent lamp starting device having a preheating electrode.

[0002]

2. Description of the Related Art Conventionally, a glow starter has been mainly used as a starting device for a fluorescent lamp, but this has drawbacks such as a long starting time and a short life. Recently, a starting circuit using a semiconductor switching element has been developed, but it is expensive and its demand is limited. For this reason, it has been desired to develop an inexpensive starting circuit using a semiconductor switch element. Based on this request, a circuit as shown in FIG. 2 using an inexpensive transistor as a semiconductor switch element has been proposed.

In FIG. 2, in this circuit, a resistor 1 is added to the base of the transistor 13 when the power supply voltage is in a positive cycle.
1, a base current flows, and a large collector current flows from the AC power supply 1 to the transistor 13 via the diode 5. At this time, the power source of the timer circuit including the resistor 6 and the electrolytic capacitor 8 is the collector of the transistor 13.
It is maintained at the emitter voltage. In this way, a half-wave of preheating current flows through the preheating electrode of the fluorescent lamp 3 to preheat it, and when the time set by the timer circuit reaches, the charge of the electrolytic capacitor 8 is applied to the gate of the thyristor 10 by the timer circuit. Flowing through the resistor 7 and the Zener diode 9, the thyristor 10 is turned on. Then,
Since the collector current of the transistor 13 is turned off,
A pulse voltage is generated by the inductance of ballast 2,
The fluorescent lamp 3 is turned on. The magnitude of the pulse voltage at this time is made constant by the resistor 15 and the surge absorber 16.

In FIG. 2, 4 is a noise prevention capacitor, 12 is a zener diode, and 14 is a capacitor.

[0005]

However, in such a fluorescent lamp lighting device, when the temperature is low or the power supply voltage is low, the preheating of the preheating electrode of the fluorescent lamp 3 becomes insufficient, and the fluorescent lamp 3 is operated once. There is a problem in that the light may not turn on with the pulse voltage of.

The present invention provides an electronic starter type fluorescent lamp lighting device capable of reliably starting a fluorescent lamp even at a low temperature or a low power supply voltage.

[0007]

The fluorescent lamp lighting device of the present invention comprises a series body of a ballast connected to an AC power source and a fluorescent lamp having a pair of preheating electrodes, and preheating of the non-power source side of the fluorescent lamp. A series body of a diode, a collector and an emitter of a transistor is connected between electrodes, and a series body of a resistor and a switch element for passing a current to the base of the transistor is connected between the collector and the emitter of the transistor, and the switch is By connecting the capacitor of the timer circuit consisting of a resistor and a capacitor to the gate circuit of the element and detecting the voltage between the preheating electrodes between the non-power supply side preheating electrodes, it is possible to determine whether the fluorescent lamp is on or off. Is connected to the lighting determination means for resistance division, and when the fluorescent lamp is not lit, the lighting determination means divides the resistance. Having a structure in which a means for decreasing the potential of the capacitor of the timer circuit by operating the voltage.

[0008]

When the fluorescent lamp is not lit with one pulse voltage, the lighting discriminating means connected between the non-power source side preheating electrodes discriminates whether the fluorescent lamp is lit or not. In case of non-lighting, reduce the potential of the capacitor of the timer circuit,
The fluorescent lamp can be turned on by repeating the operation of turning off the switch element and turning on the transistor again and repeatedly generating the pulse voltage.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the fluorescent lamp lighting device of the embodiment of the present invention comprises a series body of a ballast 2 connected to an AC power source 1 and a fluorescent lamp 3 having a pair of preheating electrodes.
The collector-emitter of the transistor 13 is connected between the non-power supply side preheating electrodes of the fluorescent lamp 3 via the diode 5. A series body of a resistor 11 for passing a base current to the base of the transistor 13 and a thyristor 10 which is a semiconductor switch element is connected between the collector and the emitter of the transistor 13. A parallel body of a Zener diode 12 and a capacitor 14 is connected between the connection point between the anode of the thyristor 10 and the resistor 11 and the base of the transistor 13. Further, between the non-power source side preheating electrodes of the fluorescent lamp 3, a timer circuit composed of a series body of a resistor 6 and a capacitor 8 and a lighting discriminating means for discriminating between lighting and non-lighting of the fluorescent lamp 3 are connected. Has been done. A resistance dividing means including resistors 17 and 18 is used as the lighting determining means. Timer circuit resistor 6 and capacitor 8
Between the connection point with and the cathode of the thyristor 10, a resistor 7
The Zener diode 9 is connected via. The Zener diode 1 is provided at both ends of the resistor 18 of the lighting determination means.
The base of the transistor 20 and the cathode are connected via 9. The transistor 20 is means for lowering the potential of the electrolytic capacitor 8 of the timer circuit by operating with the voltage divided by the lighting determination means when the fluorescent lamp 3 is not lit. The capacitor 21 connected in parallel with the resistor 18 is for making the waveform blunt with the resistance value R of the resistor 18 and the capacitance C of the capacitor 21 so as not to judge that the pulse voltage is not lit. The collector-emitter of the transistor 20 is connected via the Zener diode 9 to the gate-cathode of the thyristor 10. The series body of the resistor 15 and the surge absorber 16 connected between the non-power supply side preheating electrodes of the fluorescent lamp 3 serves to make the magnitude of the pulse voltage generated by the inductance of the ballast 2 constant.

Next, the operation of the fluorescent lamp lighting device will be described. First, when the power supply voltage is a positive cycle,
Since the base current is supplied to the base of the transistor 13 via the resistor 11, the AC power source 1 supplies the diode 5 to the base.
A large collector current flows through the transistor 13 via the. At this time, the power supply of the timer circuit composed of the resistor 6 and the electrolytic capacitor 8 is maintained at the collector-emitter voltage of the transistor 13. In this way, a half-wave of preheating current flows in the preheating electrode of the fluorescent lamp 3 and is preheated, and when the time set by the timer circuit is reached, the timer circuit causes the electrolytic capacitor between the gate and cathode of the thyristor 10. The charge of 8 flows through the resistor 7 and the Zener diode 9, and the thyristor 10 is turned on.
As a result, the collector current of the transistor 13 is cut off, so that a pulse voltage is generated due to the inductance of the ballast 2, and the fluorescent lamp 3 is turned on.

Now, a case where the fluorescent lamp 3 is not turned on by one pulse voltage will be described below.

First, when it is determined that the fluorescent lamp 3 is not lit by the resistance dividing means connected between the non-power source side preheating electrodes of the fluorescent lamp 3, the Zener diode 19 is turned on by the voltage of the resistor 18, and the transistor 20 is turned on. Since the electric charge of the electrolytic capacitor 8 is discharged through the resistor 7, the potential of the electrolytic capacitor 8 decreases and the Zener diode 9 and the thyristor 10 are turned off. Then,
The transistor 13 is turned on again. In this way
The transistor 13 is repeatedly turned on and off, and the fluorescent lamp 3 is turned on by repeating the operations of preheating the preheating electrode of the fluorescent lamp 3 and generating a pulse voltage.

When the lighting judging means composed of the resistance dividing means judges that the fluorescent lamp 3 has been turned on, the Zener diode 19 is turned off and the transistor 20 is turned off. Then, the electric charge of the electrolytic capacitor 8 is discharged between the gate and the cathode of the thyristor 10 via the resistor 7 and the Zener diode 9, the thyristor 10 is turned on, the transistor 13 is turned off, and the pulse voltage generating operation is stopped. . As a result, the fluorescent lamp 3 is lit stably.

Although the above embodiment has described the case where the capacitor 21 is connected in parallel with the resistor 18, the resistance division ratio between the resistor 6 and the resistor 7 is set so that the thyristor 10 is turned on by the pulse voltage. As a result, the transistor 13 can be turned off and the fluorescent lamp 3 can be maintained in stable lighting, and the capacitor 21 can be omitted.

[0016]

As described above, the fluorescent lamp lighting device of the present invention repeatedly generates a pulse voltage when the fluorescent lamp does not light with one pulse voltage at low temperature or low power supply voltage. By doing so, the fluorescent lamp can be reliably turned on.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a fluorescent lamp lighting device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional fluorescent lamp lighting device.

[Explanation of symbols]

 1 AC power supply 2 Ballast 3 Fluorescent lamp 5 Diode 6,7,11,17,18 Resistance 8 Electrolytic capacitor 9 Zener diode 10 Thyristor 12,19 Zener diode 13,20 Transistor

Claims (1)

[Claims] 1. A series body comprising a ballast connected to an AC power source and a fluorescent lamp having a pair of preheating electrodes, wherein a diode, a collector and an emitter of a transistor are connected in series between the non-power source side preheating electrodes of the fluorescent lamp. A body circuit is connected, and a series body of a resistor and a switch element for passing a current to the base of the transistor is connected between the collector and the emitter of the transistor, and a timer circuit including a resistor and a capacitor in a gate circuit of the switch element. Connected to the non-power source side preheating electrodes, and connected to the non-power source side preheating electrodes lighting determination means consisting of resistance dividing means for determining whether the fluorescent lamp is lit or not lit. In addition, when the fluorescent lamp is not lit, the timer is operated by the voltage divided by the resistance by the lighting determination means. Fluorescent lamp lighting apparatus, characterized in that a means for decreasing the potential of the capacitor of the road.