JP3049979B2 - Fluorescent lamp lighting device - Google Patents

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 it has disadvantages such as a long starting time and a short life. Recently, starting circuits using semiconductor switching elements have been developed, but are expensive and have limited demand. For this reason, it has been desired to develop an inexpensive starting circuit using a semiconductor switching element. Based on this request, the inventor has proposed a circuit as shown in FIG. 2 using an inexpensive transistor as a semiconductor switch element.

Referring to FIG. 2, in this circuit, when the power supply voltage is in a positive cycle, a base current is supplied to the base of transistor 13 via resistor 11, so that transistor 13 is connected from AC power supply 1 through diode 5. A large collector current flows through 13. At this time, the power supply of the timer circuit including the resistor 6 and the electrolytic capacitor 8 is connected to the transistor 13
Is maintained at the collector-emitter voltage. In this way, a half-wave of preheating current flows through the preheating electrode of the fluorescent lamp 3 and the preheating current is preheated. When the time set by the timer circuit is reached, the electrolytic circuit 8 is connected between the gate and cathode of the thyristor 10 by the timer circuit. Of the thyristor 1 flows through the resistor 7 and the Zener diode 9.
0 turns on. As a result, the collector current of the transistor 13 is cut off, a pulse voltage is generated by the inductance of the ballast 2, and the fluorescent lamp 3 is turned on. If the fluorescent lamp 3 is not turned on by one pulse voltage, the resistance dividing means connected between the non-power-supply-side preheating electrodes of the fluorescent lamp 3 determines that the fluorescent lamp 3 is not turned on. The diode 19 is turned on, the transistor 20 is turned on, and the electric charge of the electrolytic capacitor 8 is discharged via the resistor 7, so that 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 repeats the on / off operation to repeat the operations of preheating the preheating electrode of the fluorescent lamp 3 and generating the pulse voltage, so that the fluorescent lamp 3 is turned on. Next, when the lighting determining means including the resistance dividing means determines that the fluorescent lamp 3 is 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 to turn on the thyristor 10 and turn off the transistor 13 to stop the operation of generating the pulse voltage. I do. As a result, the fluorescent lamp 3 is stably turned on.

The reason why the capacitor 21 is connected in parallel with the resistor 18 of the resistor dividing means is that the waveform is blunted by 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 turned on. That's why.

In FIG. 2, reference numeral 4 denotes a noise prevention capacitor.

[0006]

However, in such a circuit, when a pulse voltage is generated, there is an on-voltage of 0.5 to 0.7 V between the anode and the cathode of the thyristor 10;
In order to turn off the transistor 13, the capacitor 1 negatively charged with the Zener voltage of the Zener diode 9
A negative potential of 4 is required. For this reason and because the minimum value of the Zener voltage of the Zener diode 9 is 3.0 V, there is a problem that the base current of the transistor 13 is insufficient and the heat generation of the transistor 13 is large. Furthermore, the Zener diode 12 is connected to the base circuit of the transistor 13.
And the components of the capacitor 14 are required. When the fluorescent lamp 3 is not turned on by one pulse voltage, the transistor 1
There is a problem that the decrease of the pulse voltage due to the heat generation of the fluorescent lamp 3 becomes large, and in the worst case, the fluorescent lamp 3 is not turned on.

An object of the present invention is to provide an electronic starter type fluorescent lamp lighting device which can start a fluorescent lamp even at a low temperature or a low power supply voltage and can suppress heat generation of a transistor.

[0008]

A fluorescent lamp lighting apparatus according to the present invention includes a series body of a ballast connected to an AC power supply and a fluorescent lamp having a pair of preheating electrodes, and a non-power supply side preheating of the fluorescent lamp. One end of the electrode is connected to the collector of the transistor, the other end of the non-power-supply preheating electrode terminal of the fluorescent lamp is connected to the emitter of the transistor via only a diode, and the base of the transistor is connected between the collector and the emitter of the transistor. A series circuit of a resistor and a switch element for passing a current is connected to the gate circuit of the switch element, and the capacitor of a timer circuit including a resistor and a capacitor is connected to the gate circuit of the switch element. Lighting discrimination comprising resistance dividing means for discriminating lighting and non-lighting of the fluorescent lamp by detecting a voltage between the electrodes. Connect stage, and the fluorescent lamp has the lighting digits set the means for decreasing the potential of the capacitor of the timer circuit by operating the resistance-divided voltage determination means configured if unlit .

[0009]

When the fluorescent lamp is not turned on by one pulse voltage, the lighting determining means connected between the non-power-supply-side preheating electrodes determines whether the fluorescent lamp is turned on or off. In the case of non-lighting, lower the potential of the capacitor of the timer circuit,
The operation of turning off the switch element and turning on the transistor again is repeated, and the pulse voltage is repeatedly generated, whereby the fluorescent lamp can be turned on. Further, since the base current of the transistor can sufficiently flow, heat generation of the transistor can be suppressed.

[0010]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a fluorescent lamp lighting device according to an embodiment of the present invention includes a series body of a ballast 2 connected to an AC power supply 1 and a fluorescent lamp 3 having a pair of preheating electrodes.
A diode 5 is connected to one end of the non-power supply side preheating electrode of the fluorescent lamp 3.
The collector of the transistor 13 is connected to the other end of the non-power supply preheating electrode terminal of the fluorescent lamp 3 through a diode 22.
, The emitter of the transistor 13 is connected. 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 switching element is connected between the collector and the emitter of the transistor 13. Further, between the non-power-supply-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 determining means for determining whether the fluorescent lamp 3 is lit or not lit are connected. Have been. A resistance dividing unit including resistors 17 and 18 is used as the lighting determination unit. A Zener diode 9 is connected via a resistor 7 between a connection point between the resistor 6 and the capacitor 8 of the timer circuit and a cathode of the thyristor 10.
The base and the cathode of the transistor 20 are connected to both ends of the resistor 18 of the lighting determination means via the Zener diode 19. The transistor 20 is a fluorescent lamp 3
Is a means for lowering the potential of the electrolytic capacitor 8 of the timer circuit by operating with the voltage divided by the resistance in the lighting determination means when is turned off. The capacitor 21 connected in parallel with the resistor 18 is connected to the resistor R and the capacitor 2 so that the pulse voltage is not determined to be non-lighting.
This is for making the waveform smooth with the capacitance C of one. The collector and the emitter of the transistor 20 are connected via the Zener diode 9 between the gate and the 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 is for stabilizing the magnitude of the pulse voltage generated by the inductance of the ballast 2.

Next, the operation of the fluorescent lamp lighting device will be described. First, when the power supply voltage is in a positive cycle,
Since a base current is supplied to the base of the transistor 13 via the resistor 11, the diode 5
, A large collector current flows through the transistor 13. At this time, the power supply of the timer circuit including the resistor 6 and the electrolytic capacitor 8 is maintained at the collector-emitter voltage of the transistor 13. In this manner, a half-wave of preheating current flows through the preheating electrode of the fluorescent lamp 3 and the preheating current is preheated. When the time set by the timer circuit is reached, an electrolytic capacitor is provided between the gate and cathode of the thyristor 10 by the timer circuit. 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, a pulse voltage is generated by the inductance of the ballast 2, and the fluorescent lamp 3 is turned on.

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

First, when the resistance dividing means connected between the non-power supply side preheating electrodes of the fluorescent lamp 3 determines that the fluorescent lamp 3 is not lit, the voltage of the resistor 18 turns on the zener diode 19 and turns on the transistor 20. Then, the electric charge of the electrolytic capacitor 8 is discharged through the resistor 7, so that the potential of the electrolytic capacitor 8 decreases, and the Zener diode 9 and the thyristor 10 are turned off. Then,
The transistor 13 turns on again. In this way,
The transistor 13 repeats the on / off operation to repeat the operations of preheating the preheating electrode of the fluorescent lamp 3 and generating the pulse voltage, so that the fluorescent lamp 3 is turned on.

When the lighting discriminating means comprising the resistance dividing means determines 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 to turn on the thyristor 10 and turn off the transistor 13 to stop the operation of generating the pulse voltage. . As a result, the fluorescent lamp 3 is stably turned on.

When a pulse voltage is generated, an on-voltage of 0.5 to 0.7 V is applied between the anode and the cathode of the thyristor 10, and the base of the transistor 13 is turned off by the forward voltage of the diode 22 to turn off the transistor 13. • Bias the emitter voltage to negative or zero. As a result, the transistor 13 can be reliably turned off,
A pulse voltage can be obtained. The diode 22
Is 0.8 V, the base current of the transistor 13 is larger than that of the circuit shown in FIG. 2, and the heat generation of the transistor 13 is reduced. As a result, even when the fluorescent lamp 3 is not lit by one pulse voltage, the fluorescent lamp 3 is lit because the decrease in the pulse voltage due to the heat generated by the transistor 13 is small.

[0017]

As described above, the fluorescent lamp lighting device of the present invention can start a fluorescent lamp even at a low temperature or a low power supply voltage, and can suppress heat generation of a transistor. It is possible to reduce the two parts of the base circuit of the transistor to one.

[Brief description of the 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 the previously proposed fluorescent lamp lighting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 2 Ballast 3 Fluorescent lamp 5,22 Diode 6,7,11,17,18 Resistance 8 Electrolytic capacitor 9,19 Zener diode 10 Thyristor 13,20 Transistor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-252093 (JP, A) JP-A-61-239599 (JP, A) JP-A-60-79697 (JP, A) JP-A 50-1979 61077 (JP, A) JP-A-58-61597 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05B 41/18-41/234

Claims (1)

(57) [Claims] A series connected to a ballast connected to an AC power supply and a fluorescent lamp having a pair of preheating electrodes, wherein a collector of the transistor is connected to one end of a non-power supply side preheating electrode of the fluorescent lamp; The emitter of the transistor is connected to the other end of the non-power supply preheating electrode terminal of the fluorescent lamp only through a diode, and a resistor and a switch element are connected in series between the collector and the emitter of the transistor to allow current to flow through the base of the transistor. A body of the fluorescent lamp is connected to the gate circuit of the switch element by connecting the capacitor of a timer circuit including a resistor and a capacitor, and detecting the voltage between the non-power-supply-side preheating electrodes and the voltage between the preheating electrodes. When a lighting discriminating means comprising a resistance dividing means for discriminating between lighting and non-lighting is connected, and the fluorescent lamp is not lit Fluorescent lamp lighting apparatus, characterized in that the means for decreasing the potential of the capacitor of the timer circuit digits set by operating the resistance divided voltage by the lighting determination means.