JPS62119899A - Preheat start type discharge lamp burner - 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 (Field of Industrial Application) The present invention relates to a lighting device for a preheating start type discharge lamp, and more specifically to a preheating start type discharge lamp lighting device that performs preheating, starting and lighting using a semiconductor element. This invention relates to an electric light lighting device.

(Prior art) A lighting device for a preheating-start discharge lamp such as a fluorescent lamp requires a lighting device that has the function of first passing current through the filament to preheat the electrode, and then applying a starting pulse. . As such a lighting device, a small and inexpensive glow starter type has been widely used.

The glow starter type lighting device will be explained with reference to FIG. The figure is a circuit diagram of a close starter type lighting device, in which a ballast 2 including an inductive element is connected to one side of a commercial power source 1, and a discharge lamp 4 has a glow lamp 3 inserted in series.
Both filament electrodes 5 and 6 are connected.

The operation of the lighting device having such a configuration will be explained. The glow lamp 3 operates a bimetallic electrode using heat generated by glow discharge in an atmosphere of inert gas 'B. When the discharge lamp 4 is connected to the power source 1, the bimetallic electrode of the glow lamp 3 is activated. The deformation causes the electrodes to be in a closed circuit state, and current flows through the filament electrodes 5 and 6 of the discharge lamp 4 to preheat them. On the other hand, in the glow lamp 3, since the electrodes are in a closed circuit state, discharge stops and the bimetallic electrodes are cooled, and when the deformation returns, the glow lamp 3 returns to an open circuit state. When this circuit is established, a kick pulse is generated from the ballast 2 containing an inductive element inserted between the power source 1 and the filament electrode 5, and when the above preheating and kick pulse conditions are met, the discharge lamp 4 is turned on. do. However, glow starter type lighting devices require preheating time due to their structure, and the timing of kick pulse generation is irregular, so there are times when sufficient pulses cannot be obtained. It takes 2 to 4 seconds for the light to turn on, and there is also the problem that flickering occurs before the light is turned on.

A rapid starter type lighting device adopted as a solution to the above problem will be explained with reference to FIG. 4. The figure is a circuit diagram of this system, in which the ballast 7 connected to the commercial power supply 1 is composed of a preheating circuit 7a and a booster circuit 7b, and the two filament windings of the preheating circuit 7a are connected to both filaments of the discharge lamp 4. The starter winding of the booster circuit 7b is connected to the commercial power source 1 and one filament electrode 5 of the discharge lamp 4 at both ends of the electrodes 5 and 6, respectively. Further, the other pole of the commercial power source 1 is connected to another filament electrode 6 of the discharge lamp 4.

The operation of the rabbit starter type lighting device configured as described above will be explained. When the lighting device is powered on, current flows through both filament electrodes 5 and 6 of the discharge lamp 4 connected to the filament winding of the preheating circuit 7a, preheating it, and when the temperature rises, the starter winding of the booster circuit 7b A voltage necessary for starting is applied from the line to the filament electrode 5, and the discharge lamp 4 is lit.

(Problems to be Solved by the Invention) However, although this rabbit starter type lighting device has the advantage of a shorter starting time of about 1 second than the glow starter type, the ballast 7 is complicated and large. There was a problem that the weight increased and the cost was high.

(Means for Solving the Problems) In order to solve the above problems, the present invention charges a capacitor with the voltage generated in both filament electrodes during a half cycle in which a preheating current is passed through both filament electrodes of a discharge lamp. ,
A half cycle in which a pulse is generated by this charged charge is discharged through a semiconductor switch such as a transistor inserted in series between both filament electrodes. At that time, the transistors etc. are turned on and off instantaneously, and a pulse with sufficient energy for activation is applied to both filament electrodes.

(Function) The voltage generated across the filament electrode during preheating is:
It varies depending on the type of discharge lamp used and the preheating method, etc.
When sufficiently preheated, a voltage of about 20V to 30V is generated. In half a cycle of preheating, the voltage and large current generated at this filament electrode generates a pulse at the base of the transistor that generates enough charge to cause the transistor to conduct.

Capacitors can be charged. Therefore, in the next half cycle of pulse generation, the charge on the capacitor causes a large current to flow through the ballast containing the inductive element, allowing the generation of a pulse with a large starting energy at the time of interruption.

(Example) A first example of the present invention will be described with reference to FIG. 1, and a second example will be described with reference to FIG. 2.

FIG. 1 shows a first example of a preheating start type discharge lamp lighting device according to the present invention.
This is a circuit diagram showing an embodiment of the present invention, in which a ballast 2 including an inductive element is connected to one side of a commercial power source 1, and a semiconductor circuit 8 enclosed by a dotted line is inserted in series with both filament electrodes of a discharge lamp 4. 5 and 6 are connected, and both poles of the filament electrodes 5 and 6 are connected to the semiconductor circuit 8.

The semiconductor circuit 8 includes a diode 9 and a semiconductor switch 10 connected in series between both filament electrodes 5 and 6 of the discharge lamp 4, and a diode 11 and a pulse generation transistor 12 connected in parallel. are connected in series. A capacitor 13 charged with a filament voltage and a thyristor 14 are connected in series between the base of the transistor 12 and the filament electrode 6 of the discharge lamp 4, and a resistor 15 is connected in parallel thereto.

moreover.

The gate electrode of this thyristor 14 is connected between two resistors 16 and 17 connected in series between both filament electrodes 5 and 6 of the discharge lamp 4 described above. Also,
A diode 18, a resistor 19, and the above-mentioned capacitor 13 are connected in series between both ends of the filament electrode 6 of the discharge lamp 4.

The operation of the lighting device configured in this way will be explained. In the figure, a preheating current is applied to the filament electrodes 5 and 6 during one half cycle of the AC cycle, and a pulse voltage is generated during the other half cycle.

The semiconductor switch 10 is a two-terminal type such as a PNPN diode, and becomes conductive in one direction when the voltage applied between both terminals exceeds a breakover voltage.

When the power is turned on, from the point at which the semiconductor switch 10 exceeds the breakover voltage, the flow flows from the filament electrode 6 through the series circuit of the semiconductor switch 10 and the diode 9 in the direction of fisimen 1 - electrode 5 and ballast 2, and the discharge lamp Preheat both filament electrodes 5 and 6 of 4. Once the semiconductor switch 10 is turned on, it remains conductive until the current becomes equal to or less than the holding current. Therefore, after the semiconductor switch 10 is turned on, the current flows until the end of the half cycle.

On the other hand, the preheating current generates a filament voltage across the filament electrode 6 of the discharge lamp 4, which is charged to the capacitor 13 through the diode 18 and resistor 19.

Next, in the half cycle on the pulse generation side, the current is in the opposite direction to that during preheating, and first from the ballast 2.

Filament electrode 5, diode 11. It begins to flow in the direction of the filament electrode 6 through the resistors 16 and 17, and as the voltage increases, the gate voltage of the thyristor 14 increases, which becomes a trigger and the thyristor 14 becomes conductive. At this time, the charge in the capacitor 13 charged during the preheating half cycle is discharged through the base of the transistor 12, so the transistor 12 becomes conductive between the collector and emitter.
Further, since the electric charge of the capacitor 13 is rapidly reduced to zero by discharging, the conduction between the collector and the emitter is interrupted. In other words, it turns on and off instantly.

This on/off operation of the transistor 12 causes instantaneous conduction/cutoff of a large current in the ballast 2 including an inductive element, resulting in a pulse with large energy.

The above operation is repeated until the preheating progresses when the power is turned on and the lighting conditions are met, and the discharge lamp 4 is lit when the conditions are met.

Since the breakover voltage of the semiconductor switch 10 is selected to be lower than the power supply voltage and higher than the tube voltage of the discharge lamp 4, the breakover voltage of the semiconductor switch 10 is selected to be lower than the power voltage and higher than the tube voltage of the discharge lamp 4.
The voltage applied to the terminal becomes less than the breakover voltage and is no longer conductive, and the preheating operation is stopped. If the preheating operation stops, no filament voltage is generated, and therefore capacitor 1
No voltage is applied to the lamp 3, the pulse generation operation also stops, and the discharge lamp 4 maintains its lighting state.

FIG. 2 shows a second example of the preheating start type discharge lamp lighting device according to the present invention.
is a circuit diagram showing an embodiment of the present invention, in which a preheating current is applied to the filament electrodes 5 and 6 in one half cycle of the AC cycle;
A pulse voltage is generated in the other half cycle, but a timer function is added to this function, and the pulse is not generated until the filament electrodes 5 and 6 are heated by the middle molecules. This was the first time a pulse was generated. In this figure, the same components as in FIG. 1 are given the same symbols, and the explanation of the circuits that they constitute will be omitted.

In the second embodiment, a diode 18, a resistor 19, and a capacitor 13 are inserted in series between both ends of the filament electrode 6 of the discharge lamp 4, and the diode 18 is inserted between the resistor 19 as a timer circuit. A thyristor 20 is inserted, and a capacitor 21 and a resistor 2 are connected in parallel with the thyristor 20.
A circuit is provided in which the capacitor 21 and the resistor 22 are connected to each other, and the gate electrode of the thyristor 20 is connected between the capacitor 21 and the resistor 22.

The operation of the lighting device configured in this way will be explained.

When the power is turned on, the preheating current begins to flow from the filament electrode 6 through the semiconductor switch 10, the diode 9, and the filament electrode 5 in the direction of the ballast 2 when the semiconductor switch 10 breaks over, Preheat filament electrodes 5 and 6. Once the semiconductor switch 10 becomes conductive, it remains conductive until the current drops below the holding current, so that current flows until the half cycle of the conductor is completed.

On the other hand, the filament voltage generated across the filament electrode 6 of the discharge lamp 4 due to the preheating current flows from the diode 18 toward the capacitor 13 through the resistor 22, capacitor 21, and resistor 19, but the value of the resistor 22 Since the voltage is high, the thyristor 20 gradually increases its gate potential.

It has the function of a timer that becomes conductive after a certain period of time has passed until the gate potential that acts as a trigger is reached. While the thyristor 20 is not conducting, only a small amount of current flows through the capacitor 13, so even if the thyristor 14 is conducting during the half cycle of pulse generation, the transistor 12
cannot be driven. However, when the thyristor 20 becomes conductive after the above-described certain period of time has elapsed, the filament voltage charges the capacitor 13 from the diode 18 through the thyristor 20 and the resistor 19. Once charged with sufficient charge to drive the transistor 12, in a half cycle of pulse generation, the transistor 12
is activated, and the ballast 2 begins to generate pulses with large energy. When the pulse begins to occur,
Since the thyristor 20 remains conductive until the discharge lamp 4 is lit, pulses continue to be generated. However, normally, the value of the resistor 22 of the timer mechanism is determined so that the filament electrodes 5 and 6 are sufficiently preheated before the pulse begins to be generated, so that the discharge lamp 4 is lit with one pulse.

As described above, according to the first and second embodiments, the capacitor 13 is charged with the filament voltage generated during the preheating half cycle, and this charge is discharged through the base of the transistor 12 during the pulse generation half cycle. By doing so, a large pulse voltage can be obtained from the ballast 2.

Note that the thyristor 14 that flows the charge of the capacitor 13 to the base of the transistor 12 and the thyristor 20 used as a timer element can be replaced with other elements such as a programmable unijunction transistor.

Furthermore, in order to improve the current amplification factor of the transistor 12,
Needless to say, two or more transistors may be used in a Darlington connection.

(Effects of the Invention) As explained above, according to the present invention, in the half cycle of flowing a preheating current to the filament electrode of a discharge lamp, a voltage generated across the filament electrode is charged to a capacitor, and this charged By discharging the charge through the base of the transistor, we can ensure that the transistor performs instantaneous conduction and disconnection actions, allowing the ballast to generate a pulse with sufficient energy to start the discharge lamp. can.

In addition, a high-performance, inexpensive, and compact lighting device that can instantly light a preheat-start type discharge lamp and that operates reliably with a simple circuit can be obtained.

[Brief explanation of drawings]

1 and 2 are circuit diagrams of a first embodiment and a second embodiment of a preheating start type discharge lamp lighting device according to the present invention, respectively, and FIGS. 3 and 4 are circuit diagrams of a conventional glow starter type and FIG. 2 is a circuit diagram of a rapid starter type preheating start type discharge lamp lighting device. 1... Commercial power supply, 2,7... Ballast, 3.
・・Glow lamp, 4 ・・Discharge lamp, 5.6・・
・Filament electrode, 7a... Preheating circuit, 7b...
- Boost circuit, 8... semiconductor circuit. 9.11.18...Diode, 10...Semiconductor switch, 12...Transistor, 13.21...
capacitor, 14, 20... thyristor, 15,
16.17.19.22...Resistance. Figure 1 14. − Thyristor diagram 2

Claims (1)

[Claims] A series circuit connected to an AC power source consisting of both filament electrodes of a discharge lamp, a ballast including an inductive element, and a first semiconductor switch that conducts for a half cycle in one direction when a predetermined voltage or more is applied; a second semiconductor switch that is connected in parallel to the semiconductor switch and conducts in a half cycle in the opposite direction to the first semiconductor switch according to a control signal; and a voltage that occurs at the filament electrode when the first semiconductor switch is conductive. A preheating start type discharge lamp lighting device comprising a capacitor charged by the above, and a circuit for discharging the capacitor while applying the charge of the capacitor as a control signal to the second semiconductor switch.