JPH06223981A - Fluorescent lamp lighting device - Google Patents

Abstract

PURPOSE:To surely start a fluorescent lamp at a specified constant pulse voltage with a low-cost constitution. CONSTITUTION:A device is provided with a series circuit composed of a stabilizer 2 connected to an AC power supply 1, and a fluorescent lamp having a pair of preheating electrodes 4, 5; a transistor 7 in which a collector and an emitter are connected to each other through a diode 6 between the preheating electrodes of the fluorescent lamp on the non-power supply side; and a timer circuit 16 composed of a resistor 8 actuated by a voltage between the collector and the emitter of the transistor 7, and an electrolytic capacitor. It is also provided with a thyristor 10 to switch the transistor 7 by a capacitor voltage of the timer circuit 16, a transistor base drive control means 17 comprising a Zener diode 11 and a resistor 12, and a surge absorber 15 provided between the collector and the emitter of the transistor 7.

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 starting device using a semiconductor switch element for a fluorescent lamp having a preheating electrode.

[0002]

2. Description of the Related Art Conventionally, as a fluorescent lamp starter,
The glow starter was mainly used, but this is
It has drawbacks such as long starting time and short life. Recently, a starter using a semiconductor switch element has been developed, but it is expensive and its demand is limited. For this reason, it has been desired to develop an inexpensive circuit device as a starter using a semiconductor switch element. Based on the above request, a circuit as shown in FIG. 3 using an inexpensive transistor as a semiconductor switch element has been proposed (Japanese Patent Laid-Open No. 3-252096).

In FIG. 3, this fluorescent lamp lighting device includes a series circuit of a ballast 2 connected to an AC power source 1 and a fluorescent lamp 3 having a pair of preheating electrodes 4 and 5, and the fluorescent lamp 3 is not connected. A series circuit of a resistor 18 and a collector-emitter of a transistor 7 is connected between the power source side preheating electrodes via a diode 6. A diode 6 is connected to the base of the transistor 7 via a resistor 12, and a thyristor 10 controlled by a timer circuit composed of a resistor 8 and a capacitor 9 is connected between the base and emitter of the transistor 7. ing. The capacitor 9 is connected to the gate circuit of the thyristor 10 via the Zener diode 11 and the resistor 19. A noise prevention capacitor 14 is connected between the non-power supply side preheating electrodes of the fluorescent lamp 3.

Next, the operation of the lighting device configured as described above will be described. When the AC power supply 1 is turned on, a base current is supplied to the base of the transistor 7 via the resistor 12 during a positive cycle of the power supply voltage, so that the collector current is supplied from the AC power supply 1 via the diode 6. Flowing. In this way, the preheating current flows in a half-wave to preheat the preheating electrodes 4 and 5 of the fluorescent lamp 3, and when the time set by the timer circuit is reached, the charge of the capacitor 9 is applied to the gate of the thyristor 10 by the timer circuit. It flows through the Zener diode 11 and the resistor 19, and the thyristor 10 is turned on. As a result, since the collector current of the transistor 7 is turned off, a pulse voltage is generated due to the inductance of the ballast 2, and the fluorescent lamp 3 is turned on.

[0005]

However, in such a conventional lighting device, at the timing when the time set by the timer circuit is reached, the voltage of the capacitor 9 turns on the zener voltage of the zener diode 11 and the turn-on of the thyristor 10. It is a time when the voltage becomes a value in the vicinity of the sum of the required gate-cathode voltage, and it fluctuates due to variations and changes in the Zener voltage and the capacitance of the capacitor, and changes in the AC power supply. Further, since there is a variation in the inductance of the ballast 2, it is difficult to always generate a pulse voltage at a predetermined voltage, which may exceed the withstand voltage of the transistor 7.

The present invention provides a fluorescent lamp lighting device capable of reliably starting a fluorescent lamp with a predetermined constant starting pulse even with respect to fluctuations in a ballast and fluctuations in an AC power source, and having a simple structure. is there.

[0007]

A fluorescent lamp lighting device of the present invention comprises a ballast to be connected to an AC power source, a series circuit of a fluorescent lamp with a preheating electrode, and a preheating electrode on the non-power source side of the fluorescent lamp. A transistor having a collector and an emitter connected via a diode, a timer circuit having a resistor and a capacitor that operate at a collector-emitter voltage of the transistor, and a transistor base that switches the transistor at the capacitor voltage of the timer circuit. A drive control circuit and a surge absorber are provided between the collector and emitter of the transistor.

[0008]

According to the present invention, by introducing the surge absorber between the collector and the emitter of the transistor, the pulse voltage generated when the transistor is turned off is clipped by the varistor voltage of the surge absorber. As a result, the pulse voltage applied to the transistor does not exceed the varistor voltage of the surge absorber even if the AC power supply voltage fluctuates, and the inductance value of the ballast or the time of the timer circuit fluctuates. Become a voltage.
Therefore, the pulse voltage for starting the fluorescent lamp is
It becomes constant, and the fluorescent lamp can be reliably turned on.

[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 according to the embodiment of the present invention includes a ballast 2 connected to an AC power source 1 and a series circuit of a fluorescent lamp 3 having a pair of preheating electrodes 4 and 5. A diode 6 is placed between the non-power supply side preheating electrodes of the fluorescent lamp 3.
Transistor 7 whose collector and emitter are connected via
And a timer circuit 16 composed of a resistor 8 which operates at a collector-emitter voltage of the transistor 7 and a capacitor 9 made of an electrolytic capacitor, and a timer circuit 16
Transistor base drive control means 17 comprising a thyristor 10 for switching the transistor 7 by the voltage of the capacitor 9 of FIG.
And a surge absorber 15 connected in parallel to a series circuit of a transistor 7 and a diode 13 connected in series with its collector-emitter. Fluorescent lamp 3
A noise prevention capacitor 14 is connected between the non-power source side preheating electrodes as usual.

Next, the operation of such a lighting device will be described. Before the fluorescent lamp 3 is started, when the power supply voltage is in a positive cycle, the base of the transistor 7 is supplied with the base current through the resistor 12 and the diode 13, so that a large amount of current is supplied from the AC power supply 1 through the diode 6. Collector current flows. At this time, the power source of the timer circuit 16 composed of the resistor 8 and the capacitor 9 is the collector-emitter voltage of the transistor 7. When the time set by the timer circuit is reached in this way, the charge of the capacitor 9 flows through the Zener diode 11 to the gate of the thyristor 10 by the timer circuit, and the thyristor 10 is turned on. As a result, since the collector current of the transistor 7 is turned off, a pulse voltage is generated due to the inductance of the ballast 2, which changes due to variations in the generated phase of the timer circuit, variations in the inductance of the ballast 2, and variations in the AC power supply 1. Pulse voltage is applied, but as shown in FIG. 2, the surge absorber 15 is connected in parallel to the series circuit of the transistor 7 and the diode 13 connected in series with its collector-emitter. The fluorescent lamp 3 is turned on without applying a voltage higher than the varistor voltage of the surge absorber 15 between the collector and emitter of No. 7.

Further, since the pulse voltage can be made constant by selecting the varistor voltage of the surge absorber 15 in this way, even in a ballast having a variation in the inductance value, a predetermined pulse voltage for lighting the fluorescent lamp is applied. It is possible to obtain a fluorescent lamp lighting device that can be secured and has higher versatility.

Next, when the fluorescent lamp 3 is turned on, the voltage between the non-power source side preheating electrodes is also reduced to the lamp voltage during lighting.
Further, when the fluorescent lamp 3 is turned on, the potential of the capacitor 9 hardly drops in the AC half cycle, and the thyristor 10 is kept on. That is, the transistor 7 is kept off and the pulse generating operation is stopped. as a result,
The fluorescent lamp 3 lights up stably.

As described above, in the fluorescent lamp lighting device according to the embodiment of the present invention, the surge absorber 15 connected in parallel is inserted in the series circuit of the transistor 7 and the diode 13 connected in series with the collector-emitter of the transistor 7. Only with a simple and inexpensive structure, the pulse voltage can be kept constant. In addition, this circuit allows the fluorescent lamp 3 to be reliably and stably started with one pulse voltage by a general-purpose ballast regardless of the ambient conditions. Therefore, the circuit can be made simpler and cheaper.

For example, in the circuit configuration shown in FIG. 1, an experiment was conducted using a surge absorber 15 having a varistor voltage of 620 V.
It was confirmed that the pulse voltage became constant at 700 V for a fluctuation of 10% and that the engine could be started reliably.

[0016]

As described above, the fluorescent lamp lighting device of the present invention has an excellent effect that the fluorescent lamp can be reliably started with a predetermined constant pulse voltage with an inexpensive structure.

[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 collector-emitter voltage waveform diagram of a transistor when a pulse is generated.

FIG. 3 is a circuit diagram of a conventional fluorescent lamp lighting device.

[Explanation of symbols]

 1 AC power supply 2 Ballast 3 Fluorescent lamp 4,5 Preheating electrode 6,13 Diode 7 Transistor 8,12 Resistance 9 Capacitor 10 Thyristor 11 Zener diode 14 Noise prevention capacitor 15 Surge absorber 16 Timer circuit 17 Transistor base drive control means

Claims (1)

[Claims] 1. A series circuit of a ballast to be connected to an AC power source and a fluorescent lamp with a preheating electrode, a transistor in which a collector and an emitter are connected via a diode between the nonheating side preheating electrodes of the fluorescent lamp, A timer circuit having a resistor and a capacitor that operate at a collector-emitter voltage of the transistor, a transistor base drive control circuit that switches the transistor at the capacitor voltage of the timer circuit, and a collector-emitter of the transistor. A fluorescent lamp lighting device comprising a surge absorber.