JPH0331037Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a high-frequency discharge lamp lighting device, which has a configuration in which a DC power supply is used to preheat the filament of the discharge lamp when lighting the discharge lamp with high-frequency output from a high-frequency inverter. The aim is to reduce the capacity of the oscillation transformer of a high-frequency inverter by improving the starting performance of electric lights.

An embodiment of this invention will be described with reference to the drawings. 1 is a positive power supply terminal of a DC power supply, 2 is a high frequency inverter, and a pair of transistors 3 and an oscillation transformer 4
It mainly consists of an oscillation transformer 4
Connect the center tap of the primary coil 5 to the power terminal 1,
Also, the emitters of both transistors 3 are connected to the negative terminal (ground) of the DC power supply. Reference numerals 6 and 7 denote secondary coils of the oscillation transformer 4, which are wound with the same polarity and connected with opposite polarity when viewed from the terminal 8 of the preheating DC power supply. 9 is a discharge lamp, 10 and 11 are its filaments, 12 is a nearby conductor, and 13 is a preheating switching element. A coil 14 wound on the secondary side of the oscillation transformer 4 is connected between the terminal 8 and one end of the filament 10. Further, the secondary coil 7 is connected between both filaments 10 and 11. A coil 15 is wound on the secondary side of the oscillation transformer 4 like the coil 14, and is connected between the secondary coil 6 and the ground via a preheating switching element 13. The coils 14 and 15 are wound with the same polarity, and are connected with opposite polarity when viewed from the power source 8. 16 is a capacitor.

Next, the operation will be explained. When the high frequency inverter 2 is in a non-oscillating state, the preheating switching element 13 is turned on and the filaments 10 and 11 are turned on.
Preheat. That is, when the switching element 13 is turned on, when viewed from the terminal 8, the coil 14, filament 10, secondary coil 7, and filament 1
The primary and secondary coils 6 and the coil 15 are connected in series via a switching element 13. Therefore, a direct current flows due to the direct current voltage applied to the terminal 8, and each filament 10, 11 is preheated. At this time, the current flowing through the coil 14 and the secondary coil 7 and the current flowing through the secondary coil 6 and the coil 15 are in opposite directions. Therefore, if the number of turns of the coils 14 and 15 is the same, and the number of turns of the secondary coils 6 and 7 is the same, the current flowing through each coil 14 and 15 and the secondary coils 6 and 7 will generate The magnetic fluxes cancel each other out. As a result, the iron core of the oscillation transformer 4 is not biased.

Next, when switching element 17 for starting is turned on and switching element 13 is turned off, high frequency inverter 2 oscillates due to switching element 17 being turned on, and high frequency output is generated in secondary coils 6 and 7. Similarly, high frequency output is generated in the coils 14 and 15 as well. In this state, a voltage obtained by adding the high frequency output induced in the coil 14 and the secondary coil 7 to the DC voltage of the terminal 8 is applied to the filament 11 as the lighting start voltage of the discharge lamp, and this voltage is applied to the adjacent conductor 1.
It becomes the potential difference with respect to 2. In this state, coil 1
4, this potential difference becomes higher by the amount of the high frequency output induced in the coil 14, making it easier for the discharge lamp 9 to start. This ease of starting can be achieved without increasing the high frequency output, compared to the case where the engine is started using only the high frequency output induced in the secondary coil 7. In other words, there is no need to increase the capacity of the oscillation transformer 4, and starting becomes easy.

As described above, since the oscillation transformer 4 is not polarized by the filament preheating current, the high frequency output induced in the secondary coil 7 is applied to both ends of the discharge lamp 9. If it is biased, the high frequency output of the secondary coil 7 will be bypassed by the secondary coil 6 and will not be applied to the discharge lamp 9. If the capacitor 16 is connected, the high frequency output of the secondary coil 6 is also applied to the discharge lamp 9, but even in this case, if the secondary coil 7 is biased,
The voltage is bypassed and is not applied to the discharge lamp 9. Therefore, if it is polarized, the discharge lamp 9
lighting becomes difficult or impossible.

As detailed above, according to this invention, the starting performance of the discharge lamp is improved by simply winding two coils in addition to the secondary coil on the secondary side of the oscillating transformer. Since the high frequency voltage can be designed to be low, the capacity of the oscillation transformer can be reduced accordingly, and this type of lighting device can be made smaller and more efficient.

[Brief explanation of the drawing]

The figure is a circuit diagram showing an embodiment of this invention. 1, 8... DC power supply terminal, 2... High frequency inverter, 4... Oscillation transformer, 6, 7... Secondary coil, 9... Discharge lamp, 10, 11... Filament, 12... Proximity conductor, 13... Switching element, 14, 15... Coil.

Claims (1)

[Claims for Utility Model Registration] It has a pair of transistors 3 and an oscillation transformer 4, and the oscillation transformer 4 is provided with first and second secondary coils 6 and 7 having the same number of turns, and First and second coils 14, 1 having the same number of turns are provided on the secondary side of the oscillation transformer 4.
a high frequency inverter 2 provided by winding 5;
A pair of filaments 10, 11 and a nearby conductor 12
and a terminal 8 of a preheating DC power source for DC preheating the filaments 10 and 11, and between the terminal 8 of the preheating DC power source and the ground, the first A switching circuit that is turned on during preheating is connected to a series circuit in which the coil 14, one filament 10, the second secondary coil 7, the other filament 11, the first secondary coil 6, and the second coil 15 are connected in series. The elements 13 are connected in series, and the direct currents flowing through the first and second secondary coils 6 and 7 are in opposite directions, and the currents flowing through the first and second coils 14 and 15 are in opposite directions. When the high frequency inverter 2 oscillates, the first coil 1 is connected to the voltage of the terminal 8 of the preheating DC power supply.
4 and the induced voltage of the second secondary coil 7 is applied between the filament 11 of the discharge lamp 9 and the proximal conductor 12, and becomes the starting voltage for lighting the discharge lamp 9. In a high frequency discharge lamp lighting device, the adjacent conductor 12 is set to a ground potential.