JPS63997A - Preheat start type discharge lamp lighter - 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 the Invention The present invention relates to a preheating start type discharge lamp lighting device that performs preheating starting and lighting using a semiconductor element.

Conventional Technology In general, lighting devices for preheat-start discharge lamps such as fluorescent lamps require a lighting device that first preheats the electrode by passing a current through the filament electrode, and then applies a starting pulse. be. As such a lighting device, it is small and
Since it is inexpensive and inexpensive, the glow starter method has been widely used. However, due to the structure of the glow starter lighting device, it takes time for the glow starter's electrode discharge to operate the bimetal before the glow starter closes and current can flow to the electrodes of the preheat-start discharge lamp. In addition, there may be cases where the timing of pulse generation is inappropriate or the pulse voltage is insufficient, so it may take 2 to 4 seconds from the time the power is turned on until the light turns on. Ta. Also, at startup,
There are also problems such as flickering, and as an alternative to the glow starter method, lighting devices using improved electronic components such as semiconductors have been proposed to shorten the lighting time and prevent flickering during startup. . FIG. 3 shows a conventional preheating start type discharge lamp lighting device.

In FIG. 3, a ballast 2 including an inductive element is connected to one of the terminals of the commercial power source 1, and a dotted line surrounds the ballast 2 between the other end of the ballast 2 and the other terminal of the commercial power source 1. semiconductor circuit 3
Both filament electrodes 5 and 6 of the discharge lamp 4 are connected in series and tangentially.

This semiconductor circuit 3 includes a diode 7 and a semiconductor switch 8.
are connected in series, and a pulse generating transistor 9 is connected in parallel with this diode 7. A thyristor 10 conductive from the base to the emitter and a resistor 14 are connected in series between the base and emitter of the transistor 9, and resistors 11 and 12 are connected in series between the collector and emitter of the transistor 9. Further, the connection point between the resistors 11 and 12 is connected to the gate of the thyristor 1o. 13 is a resistor connected between the base and collector of the transistor 9.

The operation of the lighting device configured in this way will be explained. This lighting device is configured to pass current through the filament electrode during one half cycle of the AC cycle and generate a pulsed voltage during the other half cycle. The semiconductor switch 8 is a bidirectional two-terminal thyristor called SSS, and when the voltage applied between both terminals exceeds a breakover voltage, both terminals become conductive.

When the power is turned on, from the moment the breakover voltage of the semiconductor switch 8 is exceeded, the filament electrode 6. A current flows through the series circuit of the diode 7 and the semiconductor switch 8 in the direction of the filament electrode 5 and the ballast 2, preheating the filament electrodes 5 and 6 of the discharge lamp 4. Once the semiconductor switch 8 becomes conductive, it remains conductive until the current becomes equal to or less than the holding current, so the current flows until the half cycle is completed.

Next, in the half cycle on the lighting pulse generation side, the current is in the opposite direction to that during preheating, and first flows from the ballast 2 through the filament electrode 5 and the semiconductor switch 8 to the collector of the transistor 9. Since the base of transistor 9 is pulled up to the collector potential by resistor 13, transistor 9 is in a conductive state and current begins to flow through transistor 9 to filament electrode 6. As the power supply voltage increases, the voltage across the series circuit of resistors 11 and 12 increases as the voltage drop across resistor 14 increases, so the voltage across resistor 12 also increases. Since the voltage across the resistor 12 is applied to the gate of the thyristor 10, when this voltage exceeds the turn-on voltage of the thyristor 1o, the thyristor 10 becomes conductive. When the thyristor 1o becomes conductive, the base of the transistor 9 is lower than the emitter potential, and the transistor 9 is instantly turned off.

At this time, the current flowing to the ballast 2, the filament electrode 5, the semiconductor switch 8, the transistor 9, the resistor 14, and the filament electrode 6 is instantly cut off, so the inductive element of the ballast 2 generates a large amount of energy. A pulse is generated.

The above operation is repeated every cycle of the AC power supply from the time the power is turned on, and when the filament electrodes 5 and 6 are preheated and the conditions are met, the discharge lamp 4 is lit.

The breakover voltage of the semiconductor switch 8 is selected to be lower than the power supply voltage and higher than the tube voltage of the discharge lamp 4, so that the voltage applied to the semiconductor switch 8 at the same time as the discharge lamp 4 lights up is below the breakover voltage. As a result, there is no conduction, and no current flows through the semiconductor circuit 3. Therefore, both the preheating operation and the pulse generation operation are stopped, and the discharge lamp 4 maintains its lighting state.

Problems to be Solved by the Invention However, this lighting device with a conventional configuration improves the problems of the glow starter type lighting device described above, and is capable of instantaneous lighting for about 1 second. However, since a lighting pulse is generated every cycle of the AC power supply from the time the power is turned on, the lighting pulse is applied even before the filament electrode of the discharge lamp 4 has warmed up at all. However, there was a problem in that the emitter coated on the filament electrode was severely worn out, shortening the life of the discharge lamp.

Means for Solving the Problems In order to solve the above problems, the present invention is designed to operate only when the filament voltage generated when a preheating current is passed through the filament electrode of a discharge lamp exceeds a certain voltage. A semiconductor switch is configured to flow only the preheating current until the filament electrode of the discharge lamp is sufficiently preheated, the generation of lighting pulses is stopped, and the lighting pulse is generated only when the middle molecule is heated. , which is applied to the filament electrode to suppress the wear of the emitter and greatly extend the life of the discharge lamp.

The filament voltage generated across the filament electrode during preheating varies depending on the type of discharge lamp used and the preheating method, but it ranges from 20V to 30V when it is sufficiently preheated.
A voltage of about V is generated.

In the present invention, immediately after the power is turned on, the temperature of the filament electrode is low and the resistance value is low, so the generated filament voltage is low, but as the temperature of the filament electrode rises due to the preheating current, the generated filament voltage also increases. By taking advantage of this phenomenon, the semiconductor switch starts operating when this voltage exceeds a certain value.

The semiconductor switch starts the operation of cutting off the current flowing through the transistor near the maximum value of the current waveform, thereby generating a pulse voltage and lighting the discharge lamp.

Embodiment An embodiment of the present invention will be explained with reference to FIG. A ballast 2 including an inductive element is connected to one terminal of a commercial power source 1, and a semiconductor circuit 3a shown surrounded by a dotted line is connected in series between the ballast 2 and the other terminal of the commercial power source 1. discharge lamp 4
Both filament electrodes 6 and 6 are connected.

This semiconductor circuit 3 includes both filament electrodes 5 of a discharge lamp 4.
A diode 7 and a semiconductor switch 8 are connected in series between and 6, and a pulse generating transistor 9 is connected in parallel with the diode 7. A resistor 13 is connected between the collector and base of the transistor 9, and a thyristor 1o is connected between the base and emitter so as to conduct in the emitter direction. The gate of the thyristor 10 is connected to the collector of the transistor 9 via a series circuit of a Zener diode 16 and a resistor 16.

- On the other hand, a diode 16 is installed at both ends of the filament electrode 6 of the discharge lamp so that the filament voltage can be rectified and charged.
A resistor 19 and a capacitor 17 are connected in series, and the voltage of the capacitor 17 is supplied from the connection point between the resistor 19 and the capacitor through the resistor 18 to the connection point between the Zener diode 16 and the resistor 16 described above.

The operation of the lighting device configured in this way will be explained. This lighting device is constructed so that a preheating current is passed through 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 8 is the same bidirectional two-terminal thyristor used in the prior art example described above.

When the power is turned on, the current flows from the filament electrode 6 to the diode 7, the semiconductor switch 8, the filament electrode 5, and the ballast 2 from the moment the breakover voltage of the semiconductor switch 10 is exceeded, preheating the filament electrodes 5 and 6. . Once the semiconductor switch 8 becomes conductive, it remains conductive until the current becomes equal to or less than the holding current.
Current flows until the end of the half cycle.

Next, in the half cycle on the pulse generation side, the current is in the opposite direction to that during preheating, and flows from the ballast 2 through the filament electrode 6 and the semiconductor switch 8 to the collector of the transistor 9. Since the base of transistor 9 is pulled up to the collector potential by resistor 13, current begins to flow through transistor 9 to filament electrode 6. At this time, when the thyristor 1o connected to the base of the transistor 9 is turned on, the current flowing through the transistor 9 is cut off and a kick pulse is generated. Since the thyristor 10 does not operate unless the middle molecule is heated, the current flowing through the transistor 9 without generating a pulse flows until the end of the half cycle and shifts to the preheating cycle. The filament electrodes 6 and 6 are preheated by repeating the above operation.

Since the temperature of the filament electrode 6 increases as preheating progresses, the filament resistance increases and the filament voltage gradually increases. This filament voltage is rectified by a diode 16 and charges a capacitor 17 through a charging resistor 19. The voltage charged in the capacitor 17 is passed through the resistor 18 to the Zener diode 15.
connected to the cand side. At the same time, since the half-cycle pulsating voltage on the pulse generation side is also applied to the cand side of the Zener diode 16 through the resistor 16, a DC voltage including AC ripples is applied to the Zener diode 16. The Zener voltage of this Zener diode 15 is selected to be the minimum voltage that occurs when the filament electrode 6 of the discharge lamp 4 is sufficiently preheated.
When the preheating is sufficient, the gate of the thyristor 1o is triggered at a high peak value in the waveform of the ripple voltage included in the DC. When the thyristor 1o turns on, it cuts off the base current of the transistor 9 and instantly cuts off the current flowing from the collector to the emitter of the transistor at the high peak value of the AC waveform. A high voltage pulse will be generated. When a pulse is generated, the filament electrodes 5 and 6 are already heated, so the discharge lamp 4 is lit at the very first pulse.

The degree of progress of preheating of the filament electrodes 5 and 6 changes depending on the power supply voltage, ambient temperature, etc. That is, when the power supply voltage is high, a sufficient preheating state is quickly achieved, but when the power supply voltage is low, it is delayed. Also, it is faster when the ambient temperature is high and slower when the ambient temperature is low. If you turn off the discharge lamp and restart it immediately, the filament temperature is high, so it will naturally reach a sufficient preheating state more quickly. Since the thyristor 1o does not operate until the temperature of the filament electrode 5.6 rises and a constant filament voltage is generated, no lighting pulse is generated.

Therefore, when the filament electrodes 5 and 6 are always preheated in a sufficiently constant state, the lighting pulse is applied to the discharge lamp 4.
is lit.

Since the breakover voltage of the semiconductor switch 8 is selected to be lower than the power supply voltage and higher than the tube voltage of the discharge lamp 4,
At the same time that the discharge lamp 4 is turned on, the voltage applied to the semiconductor switch 8 becomes less than the breakover voltage and is no longer conductive, so that no current flows through the semiconductor circuit 3. Therefore, as in the conventional example, the preheating operation and the pulse generation operation are stopped, and the discharge lamp 4 remains lit.

FIG. 2 is a graph showing the relationship between the preheating time of the discharge lamp and the power supply voltage in the embodiment of the present invention. According to this graph, the preheating time is about 1 second at the rated voltage of 100V, but it is about 0.5 seconds at 110V, and about 3.5 seconds at the low voltage of 90V, so the preheating time changes depending on the power supply voltage. I know what you're doing. As these devices have a function to automatically adjust the preheating time according to conditions, the discharge lamp can be lit with a single lighting pulse.

As a result of conducting a flashing test using a 30 watt fluorescent lamp at the rated voltage, turning it on for 30 seconds and turning it off for 30 seconds, we found that even after 80,000 cycles, the ends of the fluorescent lamp tube did not darken due to the lighting pulses. I couldn't.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, after the filament electrode of the discharge lamp is heated by a preheating current flowing through the filament electrode of the discharge lamp, a pulse necessary for lighting is applied to the filament of the discharge lamp. Therefore, even if the preheating speed changes due to fluctuations in the power supply voltage, it has a function that automatically controls the preheating time so that the pulse is generated after the necessary and sufficient preheating state is reached.
- A discharge lamp can be lit by the emitted pulse.

Therefore, the pulse applied to the filament electrode of the discharge lamp at the time of starting lighting is the minimum necessary, and since it is applied when the middle molecule is heated, the wear of the emitter, which is coated on the filament electrode, is extremely small and the emission It is possible to realize a preheating start type discharge lamp lighting device that can significantly extend the life of an electric lamp.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an embodiment of the preheating type discharge lamp lighting device according to the present invention, Fig. 2 is a characteristic diagram showing the relationship between power supply voltage and preheating time in the preheating type discharge lamp lighting device, and Fig. 3 is a characteristic diagram showing the relationship between power supply voltage and preheating time in the preheating type discharge lamp lighting device. FIG. 2 is a circuit diagram of a conventional semiconductor lighting device. 1... Commercial power supply, 2... Stabilizer, 3,
3a...Semiconductor circuit, 4...Discharge lamp,
6.6...Filament electrode, 7...
Diode, 8...Semiconductor switch, 9...
...Transistor, 1o...Thyristor, 1
1.12, 13, 14, 18, 18.19...
Resistor, 16... Zener diode, 16...
...cocondenser. Name of agent Patent attorney Toshio Nakao and one other person 111yama''! A'td. Urahat Atonement Book Shiq --- L Lange Style O --- π Iri Z f3. f6. t8. Condensing Figure 2/source transduction pressure CV)

Claims (1)

[Claims] a first series circuit connected between one terminal of each of the two electrode filaments of the discharge lamp, the first series circuit consisting of a ballast including an inductive element and an alternating current power source; and the other terminal of each of the two electrode filaments. , a second series circuit consisting of a first semiconductor switch and a diode that conducts in both directions when a voltage higher than a predetermined voltage is applied; and a second series circuit that is connected in parallel to the diode and conducts in the opposite direction to the diode by a control signal. A preheating start type discharge lamp lighting device comprising: a second semiconductor switch that is cut off; and means for generating a control signal that cuts off the second semiconductor switch in accordance with a filament voltage between terminals of the electrode filament.