JPS61211998A - Discharge lamp circuit - 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 [Eleventh Industrial Field] The present invention relates to a discharge lamp circuit having an inverter and for lighting a °C warning light or a discharge lamp similar thereto.
K relates to a discharge lamp circuit that can extend the life of the discharge lamp.

[Conventional technology]

A discharge lamp circuit equipped with an inverter is known, for example, in "Journal of the Illumination Institute of Japan," Vol. 64, No. 3, No. 181, published in 1982.

Generally, the circuit shown in FIG. 4 is also known. In the circuit shown in FIG.
, Try, resistors fb and Rt, a sympathetic capacitor C1, and an output transformer (2), and is connected to a DC Il source circuit (3) consisting of a rectifier. In addition.

The output transformer (2) includes a primary winding N1 having a center tap, a base drive winding N, a lamp voltage supply coil Ns that generates high voltage, and a pair of electrode heating voltage supply coils N, , N. , consists of. Furthermore, a pair of transistors Tr1. Tr is connected to both ends of the next winding N,
t#(3) is connected to the center tap of the primary winding N, thereby forming a parallel inverter.

(4) is a warning light, and a pair of heater electrodes (5) f6
), that is, it has a heatable filament electrode. A pair of heater electrodes (5) (6) are connected to a pair of t-pole heating voltage supply coil N4, and further a pair of heater t
A lamp voltage supply coil N1 is connected between the poles (51 and 6) via a stabilizing capacitor C2. (7) is a switch circuit, and is connected to short-circuit both ends of the lamp voltage supply coil N1. and four bridge-connected diodes D, Da, Ds, Da, and a transistor Tr.

It consists of τ.

In this circuit, the inverter (1) converts direct current into alternating current by a known operation similar to the circuit described in the above-mentioned journal of the Institute of Illumination, and drives the warning light (4).

By the way, in order to extend the life of the warning light (4),
Heater electrode (5) Without applying high voltage from coil N1 to the warning light at the same time as the heat of (6), heater electrode (5)
It has already been shown that it is desirable to first heat the coil (6) by applying a voltage to it and then applying a lamp voltage. In the circuit shown in FIG. 4, at startup, a pace current is supplied to the AC switch circuit (power transistor Tr), turning it on and connecting both ends of the coil N1.

[Problem that the invention seeks to solve]

It is desirable that the voltage of the heater electrodes (5) and (6) be high at startup for preheating, but if a high voltage continues to be supplied even after startup, the life of the warning light (4) will be shortened. However, the fourth
In the conventional circuit shown in the figure, it is not possible to reduce the voltage required to heat the heater 11 poles after turning on. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a discharge lamp circuit that can lower the voltage for turning off the heater tlj after one lighting operation.

[Means for solving problems]

The discharge lamp circuit according to the present invention which achieves the above-mentioned objects is equipped with an output transformer having a pair of coils for supplying heating voltage, a coil for supplying voltage, and an inverter for converting direct current into alternating current. and a pair (7) of heaters 11
The pair of electrode heating voltage supply coils are respectively connected to the pair of heater electrodes, and the lamp voltage supply coil is connected between the pair of heater electrodes. It has a frequency characteristic such that the impedance value decreases as the temperature increases. Polar heating voltage supply coil and the pair of heat z! and a pair of impedance elements connected respectively between the poles.

The lamp voltage supply coil is placed in an unloaded state between the time when the voltage supply by the 11-pole thermal voltage supply coil starts and the time when the discharge lamp is lit, and the lamp voltage is supplied when the discharge lamp is lit. coil Y and a switch circuit connected between the pair of heater electrodes.

[For production]

In the discharge lamp circuit of the present invention, a voltage is supplied to the housing heater electrode, but a lamp voltage is not supplied. At this time,
The lamp voltage supply coil is disconnected from the discharge lamp by the switch circuit and is in an unloaded state. 9. When the load of an inverter becomes lighter, the output frequency becomes higher. It has a % note that the heavier the load, the lower the output frequency. Therefore, a high frequency voltage is obtained in the transformer OtS galvanic pressure supply coil before one lighting (before the lamp voltage is supplied).

'The IJI heating voltage supply coil is connected to the heater electrode via an impedance element with frequency characteristics such as a capacitor, so at high frequencies, the pressure drop due to the impedance element is small, and a high voltage is applied to the heater electrode separately. , quickly heat up the sword to zero. After that, turn on the switch circuit.

The lamp voltage supply coil is connected to the discharge lamp via a switch circuit, increasing the load on the inverter.

As a result of this, the output frequency decreases, the impedance value of the impedance element increases, and the voltage applied to the heater electrode decreases, thereby preventing a decrease in the life of the discharge lamp.

〔Example〕

Next, a description will be given of FIGS. 1 and 3 showing a warning light circuit according to an embodiment of the present invention. However, in Figures 1 and 3, parts common to those in Figure 4 are given the same symbol +f, and their explanation will be omitted.

FIG. 1 shows an example of the embodiment shown in FIG. Capacitors C1 and C4 are connected to each other.Also.

A switch circuit (7) is connected in series between the lamp voltage supply coil Nl and the heater pole (5). The structure other than 7 is the same as that shown in FIG. 4.

When turning on the warning light (4) with this circuit, first.

'@Turn on source switch SW4 and turn on ttsv.

At this time, the transistor Tr1 is kept off, and the rung voltage supply coil N is placed in an unloaded state. To this J:
As a result, the inverter (1) is in a light load state and a high frequency output voltage is generated. Therefore, a high frequency voltage is applied to capacitor C from i & extreme heat voltage supply coil N4N.
,,C, and heater electrodes (5) (6) (mouth)
applied to the road. Since the impedance value of capacitors C, , C, becomes small when the frequency is high, -ta t lj
(5) (6) The high voltage is reduced and preheating is performed quickly. After that, the power switch SW is also turned on with a slight delay, and when the transistor Trm'l is turned on, the lamp voltage supply coil N is connected to the warning light (4) and turned on. Since the park (1) becomes a heavy load, the output frequency decreases, the impedance value of the capacitors C, C, becomes large, and the 710 heating voltage and current of the heater pole (5) +6) becomes small. . As a result, fluorescent lamp heater 1! Pole (51
(6) Automatically suppresses the flow of current in excess of K.

Fluorescent lamps have a longer lifespan.

In addition, while the inverter (1) is operating? The collector % current Ic, the collector-emitter voltage V, and the base-emitter voltage vBF of the transistor TrI are as follows.

E Figure 2 (A1(ji(O)).

FIG. 3 shows a fluorescent lamp circuit according to a second embodiment of the present invention.

In this circuit, first and second lamp voltage supply coils NsA and N513 are provided, these are connected in series, and a switch circuit (7) is connected between them. The switch circuit (power transistor 1r, is the first
As in the case shown in the figure, it is turned on when supplying lamp voltage to the fluorescent lamp (4).

As described above (, two lamp voltage supply coils NsA,
If a switch circuit (chip) is placed between the NIB and the transistor Tr3, the voltage applied to the transistor Tr3 will be half of that shown in FIG.

Although the embodiments of the present invention (σ) have been described above, the present invention is not limited thereto, and includes further modifications. For example, the inno(-ta) (1) is not limited to the circuit shown in Figure 1 σ, but as long as the frequency is high when the load is light and the frequency is low when the load is l, then A switch circuit (7
)'kFET, SIRISK, or other switching elements may be used. The present invention is not limited to IL fluorescent lamps (4), and can be applied to various types of discharge lights similar thereto. Also, heater 1
! It is also applicable to a structure in which the pole (51(6)) is separated into a heater and an IL pole for supplying lamp pressure.

〔Effect of the invention〕

As is clear from the above, according to the present invention, 1! at startup!
It is automatically achieved that a high heating voltage is supplied to the pole and a low heating voltage is supplied after one lighting operation, thereby extending the life of the discharge lamp.

4. ffFIj of the drawing! Figure 1 is a circuit diagram showing a fluorescent lamp circuit according to the first embodiment of the present invention, Figure 2 is a waveform diagram of each part of the circuit, and Figure 3 is a circuit diagram showing the fluorescent lamp circuit according to the second embodiment. Figure 4 is a circuit diagram showing a conventional fluorescent lamp circuit.〇(1)...impark, (2)...output ratio %
(4) Fluorescent lamp, (5) (61... Heater electrode, (Power... Switch circuit, N,... Lamp voltage supply coil, N, , N,...) 0 thermal voltage supply coil.

Claims (2)

[Claims] (1) An inverter equipped with an output transformer having a pair of electrode heating voltage supply coils and a lamp voltage supply coil to convert direct current into alternating current; A discharge lamp has a discharge lamp in which electrode heating voltage supply coils are connected to each other, and the lamp voltage supply coil is connected between the pair of heater electrodes, and the discharge lamp has a frequency characteristic such that the impedance value decreases as the frequency increases. and a pair of impedance elements connected between the pair of electrode heating voltage supply coils and the pair of heater electrodes, respectively, and lighting the discharge lamp from the time when voltage supply by the electrode heating voltage supply coil starts. A discharge lamp circuit comprising: a switch circuit that brings the lamp voltage supply coil into a no-load state during the period of time, and connects the lamp voltage supply coil between the pair of heater electrodes when the discharge lamp is lit. (2) The lamp voltage supply coil is divided into a first coil and a second coil, and the switch circuit is connected between the first coil and the second coil. A discharge lamp circuit according to claim 1, which is a discharge lamp circuit.