JPS5854548A - Lighting device for electric-discharge lamp - 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 The present invention relates to a discharge lamp lighting device that lights a discharge lamp using high frequency and is dimmable.

The AC power source is controlled by phase control, and the DC voltage obtained by full-wave rectification is input to the inverter, and a discharge lamp such as a fluorescent lamp is lit with a side frequency of 2 to 3 KHz or higher using the inverter, and the phase control Dimming by changing the angle has been attempted in the past because it provides good dimming with little flicker. As such a device, the device shown in FIG. 1 has been known.

In FIG. 1, 1 is an AC power source, 2 is a dimming device that controls the phase of the voltage of the AC power source I, a bidirectional thyristor 3, and a control device 4 that controls the phase at which conduction starts.
It consists of

In addition, 6 is an inverter, which here consists of a Hush-pull type inverter having a resonant circuit, and its input is a DC voltage obtained by rectifying the output of the dimmer 2 with a full-wave rectifier 5. 7 is a preheating electrode 7f for fluorescent lamps, etc. It is a discharge lamp having f.

Inverter 6 has output winding 8s, collector winding 8cl, 8
c2. Base feedback winding 8b, filament winding 8fl,
8 fl, and includes an output transformer 8 consisting of a leakage transformer, switching transistors 9a and 9b, a high frequency choke coil io, and a resonant capacitor it, /
(It is composed of ear resistors 12a, 12b, etc.).

That is, collector windings 8C1, 8C! The connection point with the full-wave rectifier R5 is connected to the positive output end of the full-wave rectifier R5. The positive output terminal II'i of the full-wave rectifier 5 is also connected to the bases of switching transistors 9a and 9b via bias resistors 12a and 12b, respectively. One end of each collector winding i118cxs8cg is connected to the collectors of switching transistors 9a and 9b, respectively.

The emitters of the switching transistors 9a, 9k) are respectively connected to both ends of the base feedback fii8b. A resonance capacitor 11 is connected between each end of the collector winding 8C1*8C1. Both emitters of the switching transistors 9a and 9b are connected to the negative output end of the full-wave rectifier 5 via a high-frequency choke coil IO. Thus, the output 8. Switching transistors 9a, 9b, high frequency choke coil 10, resonance capacitor I1. A di-inverter is formed by the bias resistors 12a and 12b.

In addition, the filament winding 8f1°8b of the output transformer 8
are connected to the preheating electrodes 7ft and 7fl of the discharge lamp 7. As this discharge lamp 7, for example, a fluorescent lamp or the like is used.

The output transformer 8 is also provided with an auxiliary winding 8.
Both ends of this auxiliary winding 8 are connected to the input end of the rectifier circuit I4. A condenser 716 is connected between the positive and negative output terminals of this rectifier circuit 14, and the positive output terminal is connected to the positive output terminal of the full-wave rectifier 5 via a diode 15. There is. The negative output terminal of the full-wave rectifier 5 and the negative output terminal of the rectifier circuit 14 are connected in common. Thus, the auxiliary winding 8 has a % rectifier circuit +4. Diode 15. The capacitor 16 constitutes an auxiliary DC power supply.

In the apparatus configured as described above, when the AC power source 1 is turned on, a full-wave rectified voltage is generated at the output terminal of the full-wave rectifier 5 as shown in FIG. 2 (Jl). When the bidirectional thyristor 3 sets its conduction start phase to a phase of 01 as shown in FIG. Supplied. A stain current is supplied to the paces of the switching transistors 9a and 9b of the inverter 6 through the bias resistors 12a and 12b during a period T1, and the pace returner @
The well-known self-oscillation is performed by the action of 8b, etc., and a high frequency voltage is generated in each winding of the output transformer 8, and the preheating electrodes 7f1.7 are preheated by the filament windings 8f, 8f, etc. , the discharge lamp 7 is turned on.

The degree of dimming and dimming is determined by the conduction start phase θ by the dimming device 2.
! This is done by changing the

During the period T1, DC power is not supplied from the dimmer 2 to the inverter 6, so during the period T1 when DC power is supplied from the dimmer 2, the voltage across the auxiliary winding 8 is changed to the rectifier circuit 1.
4 to charge the capacitor 16, and its terminal voltage Vc
When p is supplied to the input of the inverter 6 during the period T, the input voltage of the inverter 6 becomes as shown in FIG. 2(b).

During the period T3 when the voltage of the capacitor 16 is applied to the inverter 6, the terminal voltage Yap of the capacitor 16 is set so that the discharge lamp 7 is turned off. The preheating electrode 7fss7f* is preheated by the filament winding 8ft*8f2, and the preheating voltage becomes as shown in 21iQ(d).

Note that FIG. 2(C) shows the discharge current of the H discharge lamp 7.

As described above, by appropriately setting the terminal voltage vCp and capacitance of the capacitor 16, the preheating electrodes 7ft and 7fx can be preheated even during the pause period of the discharge current, so that the dimming of the discharge lamp 7 can be smoothly controlled. The purpose is to suppress deterioration of the electrodes of the discharge lamp 7 and extend the life of the discharge lamp 7.

However, in such conventional devices, the light control device 2
When the DC voltage from the inverter 6 becomes low and the input voltage of the inverter 6 becomes the voltage of the capacitor 16, if the voltage of the capacitor 16 increases due to fluctuations in the AC power supply l, the discharge of the discharge lamp 7 continues without pausing. It's easy to get 17.

If the discharge continues, dimming cannot be performed smoothly, and the charge in the capacitor 16 is suddenly discharged.
The terminal voltage suddenly decreases and the single-child thermal electrode "t+"
7f! It becomes impossible to preheat.

Furthermore, if the voltage of the capacitor 16 is set low to prevent the discharge from continuing, the input voltage of the inverter 6 decreases, and the voltage of the filament windings 8ft, 8f decreases, thereby sufficiently preheating the preheating electrodes 7fl, 7f. I become unable to do so.

Furthermore, since the capacitor 16 requires a large-capacity electrolytic capacitor, the lighting device tends to be bulky, and the life of the electrolytic capacitor tends to be short.

The present invention eliminates the above-mentioned conventional drawbacks and provides a discharge lamp lighting device that can perform smooth dimming by sufficiently preheating the inverter during the period when DC power is supplied from the dimming device. The purpose is to

Embodiments of the discharge lamp lighting device of the present invention will be described below with reference to the drawings. FIG. 3 is a circuit diagram showing the configuration of one embodiment. In order to avoid duplication in the figure, the same parts as in FIG. I will focus on the parts that differ from the above.

In this FIG. 3, AC power supply 1. Dimmer device 2゜bidirectional thyristor 3. Control device 4. Full wave rectifier 5. Inverter 6, discharge lamp 7. The output 8° switching transistors 9m and 9b, the high frequency choke coil TO, the resonance capacitor 11, and the bias resistors 12m and 12b are the same as those shown in FIG. This invention is a new preheating control circuit!
7 and a preheating circuit 25 are added.

In other words, the preheating control circuit 17 is a trigger circuit! 8.20, a delay circuit 19 that determines the preheating start phase, a delay circuit 21 that determines the preheating time, and a DC power source 23 obtained by stepping down the voltage of the AC power source 1 or the like.

The trigger circuit 18 is configured as follows.

That is, between the positive and negative output terminals 11 of the full-wave rectifier 5
C resistors 18a and 18c are connected in series, and a connection point between these resistors 18a and 18c is connected to the pace of a transistor 18f via a resistor 18b. The emitter of the transistor 18f is connected to the negative pole of the DC power supply 23, and the collector is connected to the positive pole of the DC power supply 23 through the resistor 18d, and also through the capacitor 18e.
It is connected to the input terminal of the delay circuit 190. This incoming end is connected to the negative electrode of the DC power supply 23 via a resistor 18g.

Power terminals of this delay circuit 19 are connected to the positive and negative electrodes of a DC power source 23, respectively. The output end of the delay circuit 19 is connected to the base of the transistor 20d via the resistor 20a of the trigger circuit 2o.

The emitter of this trigger circuit 2o is connected to the negative pole of the DC power supply 23, and the collector is connected to the DC power supply 23 through a resistor 20b.
as well as connected to the positive terminal of.

It is connected to the input end of the delay circuit 21 via a capacitor 20c. The input end of this delay circuit 21 is grounded via a resistor 20fk. The trigger circuit 20 is thus configured.

The source terminal of the delay circuit 21 is the positive terminal of the DC power supply 23.

Connected to negative pole. The output terminal of this delay circuit 21 is connected to a transistor 28 in a preheating circuit 24 through a resistor 22.
connected to the base of. The above two delay circuits 19'
, 21 are each composed of a monostable multi-by-break.

The collector of the transistor 28 in the fC% preheating circuit 24 is connected to the positive electrode of the DC power supply 23, and the emitter of this transistor 28 is connected to the input terminal of the oscillation circuit 27. The output terminal of the oscillation circuit 27 is the transistor 26
connected to the base of. The transistor 28IIi controls the operation of the oscillation circuit 27, and drives the transistor 26.
is adapted to drive a preheating transformer 25.

The emitter of the transistor 26 is connected to the negative electrode of the DC power supply 23, and the collector is connected to the primary winding 25c of the preheating transformer 25.
It is connected to the positive side output end of the full-wave rectifier 5 via. This preheating transformer 25 has two filament windings 41.
25 fx, 25, etc., and these filament windings 25 fl, 251* are respectively connected to the discharge lamp 7.
Preheating electrode 7ft, 7f! It is connected to the.

Next, the operation of the discharge lamp lighting device of the present invention configured as described above will be explained. When the AC cylinder mt is turned on, the conduction start phase of the bidirectional thyristor 3 is controlled by the signal from the control device 4, and the full-wave rectified voltage due to the total conduction angle of the bidirectional thyristor 3 (Fig. 4 (1)) For example, if the phase is set to 02 as shown in FIG. 4(b), the inverter 6 is connected to the inverter 6 via the full-wave rectifier fii5 as shown in FIG. 4(b).
As shown in the input voltage of the inverter 6, DC power is supplied for a period T3.

During the period T3, bias resistors 12a and 12 are connected to the bases of the switching transistors 9g and 9b of the inverter 6.
A base current is supplied to the base feedback winding 8b, and by the action of the base feedback winding 8b, etc., self-sustained oscillation occurs as is well known, generating a high frequency voltage in each winding of the output transformer 8, and lighting the discharge lamp 7.

Further, the intensity of the v14 light is determined by changing the conduction start phase θ1 by the dimmer 2 and by changing the period T3 during which the discharge lamp 7 is lit by applying a DC voltage to the inverter 6.

On the other hand, when the input voltage of the inverter 6 and the DC power supply 23 obtained by stepping down and rectifying the AC power supply 1 etc. are applied to the preheating control circuit I7, the trigger circuit 18 operates as shown in FIG. 4(d). A trigger signal is generated at a phase of θ0 when the AC power supply 1 becomes OV.

A trigger signal is applied to the delay circuit 19, and the delay circuit 1
9 operates, and after a delay time T4 shown in FIG. 4(d) has elapsed, an output is generated at a phase of θ1, and the output becomes rLJ.

This output 4 is further applied to a trigger circuit 20, which generates a trigger signal with a phase of θ1 and applies it to the delay circuit 2L.

When a trigger signal is applied to the delay circuit 21 at a phase of 0m, the output becomes rHJ9. Predetermined delay time +1'l.

After lapse of time, the output becomes "L" at a phase of θ4. That is, as shown in FIG. 4(d), the output of the delay circuit 21 is T from the phase 03 to the phase 04, and the output is rH.
It becomes J.

During the period when the output of the delay circuit 21 is rHJ, the transistor 28 of the preheating circuit 24 is conductive, and the DC power supply 23 is applied to the oscillation circuit 27 through the transistor 28.

The oscillation circuit 24 starts oscillating, and a preheating voltage is generated in the filament windings 25f1*25b by the switching operation of the transistor 26 and the action of the preheating transformer 25, and the preheating electrode 7fss7f! Preheat.

When the output of the delay circuit 21 becomes rLJ at a phase of 04,
The transistor 28 is cut off and the oscillation circuit 27 stops oscillating. In other words, the current emitted by the discharge lamp 7 is as shown in Fig. 4 (
As shown in c), the discharge current flows during the period T3 when the DC power is applied to the inverter 6, and the preheating electrodes 7fl, 7f are preheated during the period T3 when the discharge current flows, as shown in FIG.
d), as shown in Figure 4(e), from the phase of 5θ3 to 0
The period becomes T until the phase becomes 4.

By performing sufficient preheating in the period of T, the time during which the discharge current does not flow is short, so that the preheating electrode 7f1,
There is almost no drop in the temperature of 7f, and the preheating electrode 7fl, 7f when the discharge current starts flowing again.

The temperature of the discharge lamp 7 can be maintained sufficiently high, and the discharge lamp 7 can be smoothly dimmed without continuing to discharge during the period when DC power is not being supplied from the dimmer 2 to the inverter 6. be.

In addition, since the phase of preheating the preheating electrode 7f1.7f is constant regardless of the degree of dimming, the preheating voltage to the preheating electrode 7f1.7 can be reduced to just one, so the lifespan of the discharge lamp 7 is longer than that of the conventional one. It can be equivalent to the device.

FIG. 5 is a circuit diagram showing the configuration of another embodiment of the invention. In this FIG. 5, the preheating control circuit 17 is connected to the trigger circuit 20 of the embodiment shown in FIG. This embodiment is the same as the embodiment shown in FIG. 4 except that an output circuit 29 is connected in place of the delay circuit 21.

This output circuit 29Fi) is mainly composed of a transistor 29c. That is, the output of the delay circuit 29 is connected to the pace of the transistor 29c via the resistor 29a.

The emitter of the transistor 29c is connected to the negative electrode of the DC power supply 23. The collector of this transistor 29c is connected to the positive electrode of the DC power supply 23 via a resistor 29b.

It is connected via a resistor 22 to the base of a transistor 28 of a preheating circuit 24 . Other parts are similar to those in FIG. 3.

In the embodiment of FIG. 5 configured as described above, the output becomes rLJ at a phase of θ- after the delay time T4 of the delay circuit 19 has elapsed, as shown in FIG. 6(C).

This output is inverted at the output circuit 29 as shown in FIG. Preheat them.

Thereafter, the preheating operation continues until the AC power supply 1 reaches the phase θ0 when it becomes Ov. That is, preheating electrode 7'1s76
The preheating is performed during the period when the discharge current is flowing through the discharge lamp 7 as shown in Fig. 6(a), and from the phase 06 to the time when the AC power source 1 reaches approximately Ov as shown in Fig. 6(c). becomes.

In this way, since the preheating period ft is set to the latter half of the phase of the output of the dimmer 2, the dimming range becomes wider.

Since the time from the end of the preheating period until the discharge current starts flowing again is short, it is possible to further suppress a decrease in the temperature of the preheating electrodes 7fl, 7f.

In the above embodiments, the inverter 6 is a push-pull type transistor inverter equipped with a high frequency choke coil, but it is of course possible to apply other inverters.

Further, as a method of preheating the preheating electrodes 7fl, 7f during a part of the period during which DC power is applied to the inverter 6 from the dimmer 2 and a discharge current is flowing through the discharge lamp 7, a third method is proposed.
Although the preheating control circuit 17.degree. and the preheating circuit 24t are shown in FIG.

In each of the above embodiments, a case has been described in which the number of discharge lamps 7 is one, but the invention is not limited to this, and two or more lamps may be lit.

Furthermore, in each of the above embodiments, one inverter corresponds to one dimmer, but multiple inverters or multiple inverters and a gold wave rectifier can be connected to one dimmer or full wave rectifier [7. Good too.

As described above, according to the discharge lamp lighting device of the present invention, DC power is applied to the inverter from the 1w4 light device,
Since the preheating electrode of the discharge lamp is preheated during a part of the period when the discharge lamp is lit, the preheating electrode can be sufficiently preheated, and the inverter is not supplied with DC power. It has the advantage of blocking the discharge of the discharge lamp and allowing smooth dimming.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of a conventional discharge lamp lighting device, and FIGS. 2(a) to 2(d) are waveform diagrams of various parts to explain the operation of the discharge lamp lighting device shown in FIG. . FIG. 3 is a circuit diagram of an embodiment of the discharge lamp lighting device of the present invention, and FIGS. 4(a) to 4(e) are waveform diagrams for explaining the operation of the discharge lamp lighting device of FIG. 3. , FIG. 5 is a circuit diagram of another embodiment of the discharge lamp lighting device of the present invention, and FIG.
) to FIG. 6(c)t;j are waveform diagrams for explaining the operation of the discharge lamp lighting device of FIG. 5. l...AC power supply, 2...dimmer, 5...full wave rectifier, 6...inverter, 7...discharge lamp, 7fl
, 7ra... Preheating electrode, 8... Output Lance, 9a,
9b... Switching transistor, 17... Preheating control circuit. 18, 20 ・) Riga circuit, 18f, 20d, 26°28...transistor, 19.21...delay circuit. 25・τ・Preheating transformer, 27...oscillator, oscillation circuit. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Shin Kuzuno - Figure 2

Claims (4)

[Claims] (1) An inverter that inputs a pulsating DC voltage obtained by full-wave rectification of the voltage of an AC power supply, a discharge lamp having a preheating electrode that is lit by the output AC voltage of this inverter, and a space between the AC power supply and the inverter. a dimmer that intervenes and performs phase control to dim the discharge lamp; a preheating circuit that preheats a preheating electrode of the discharge lamp; and a period during which power is applied to the inverter via the dimmer. A discharge lamp lighting device comprising: a preheating control device configured to operate the preheating circuit for a predetermined period of time to preheat a preheating electrode. (2) The preheating control circuit is a first trigger circuit that generates a trigger signal in a phase in which the AC power supply becomes O■. A patent claim characterized in that a delay circuit that is triggered by the output of the first trigger circuit and outputs the output with a predetermined time delay is the same as an output circuit that inverts the output of the delay circuit and drives the preheating circuit. Discharge lamp lighting device 8 according to item 1 in the range of (3) The preheating control circuit includes a first trigger circuit that generates a trigger signal at a phase when the pre-distribution AC power supply becomes 0. a first delay circuit that is triggered by the output of the tenth trigger circuit and outputs the signal after a first predetermined time delay; a second trigger circuit that is triggered by the output of the first delay circuit; and a second trigger circuit that is triggered by the output of the second trigger circuit and is output with a second predetermined time delay to delay the preheating circuit for a predetermined time. 2. The discharge lamp lighting device according to claim 1, further comprising a second delay circuit. (4) The preheating circuit includes a first transistor that is driven by the output of the preheating control circuit, an oscillation circuit that performs an oscillation operation when the first transistor is turned on, and a first transistor that is turned on by the output of this oscillation circuit. 2. The discharge lamp lighting device according to claim 1, further comprising a preheating transformer that applies a voltage to the preheating electrode when the second transistor is turned on.