JPS58189992A - Device for firing 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 for lighting a discharge lamp at high frequency, and particularly to a means for preheating electrodes at the time of starting the device.

Conventionally, a discharge lamp lighting device shown in FIG. 1 has been proposed.

This conventional example will be explained below with reference to FIG.

In FIG. 1, l is a commercial AC power supply, 2 is a rectifier that inputs and rectifies the AC voltage from the commercial AC power supply 1, and 3 is a converter that converts the pulsating DC voltage rectified by the rectifier 2 into a high frequency voltage. Self-excited oscillation type Puno 7 Yuble type transistor Inno (-ta, 4 is a preheating electrode 4a, 4 that lights up when the high frequency output voltage of the transistor inverter 3 is fully input)
bkM fluorescent pair.

Next, the structure of the above-mentioned transistor Inno (3) will be explained.

Reference numeral 5 denotes a harmonic choke coil, through which the positive output end of the rectifier 2 is connected between a pair of primary windings 6a and 6b of a leaky output transformer 6. , while the negative output terminal of the rectifier 2 is connected to the emitters of a pair of main switching transistors 'I&, 7b.

The bases of the main switching transistors 7a and 7b are connected to both ends of the base winding @6c of the output transformer 6, and are also connected to the resistor 9 and the emitter of the transistor 12 via base resistors 8a and 8b'z, respectively. There is.

The collectors of the main switching transistors 7g and 7b are connected to one end of the primary windings 96a and 6b, respectively, and a resonance capacitor 11 is connected between the collectors of the amphibodi switching transistors 7a and 7b.

Further, an auxiliary winding 6d is provided on the primary side of the main cadence 6, an output winding 6e for lighting the fluorescent light *1≠'4 is provided on the secondary side, and the electrodes 4a, 4b are completely preheated or It has electrode windings 6f and 6g for heating. 12 is an auxiliary DC power supply, which connects the auxiliary winding 6d and this auxiliary winding @6.
d, and a smoothing capacitor 12b connected to the cathode of the rectifier diode 12a and the other end of the auxiliary winding 6d.

The positive output terminal of this auxiliary DC power supply 12 is connected to the transistor 1
3, the negative output terminal is connected to the negative output terminal of the rectifier 2, the base of the transistor 130 is connected to resistors 9 and 10 via a resistor 14, and the resistor l
The other end of O is connected to the positive output end of the rectifier 2.

Next, the entire configuration of the starting circuit 15 provided in the transistor inverter 3 will be explained.

15a is a resistor, one end of which is connected to the output terminal of the positive OIl of the rectifier 2, and the other end of which is connected to one end of a resistor 15b connected to the negative output terminal of the rectifier 2.

The cathode of the voltage diode 15c is connected to the contact point of the resistors 15a and 15b, and the voltage diode 15c
The anode of transistor 15d is connected to the base of transistor 15d. The emitter of this transistor 15d is connected to the negative output terminal of the rectifier 2, and the collector is connected to the resistor 9, 10.14.
connected to the contacts. Further, a resistor 15e and a capacitor 15f connected in series with the resistor 15e are
It is connected to the positive side and negative side output ends of the auxiliary power source 12, respectively. The cathode of a voltage diode 15g is connected to the contact between the resistor 15e and the capacitor 15f, and the anode is connected to the base of the transistor 15h. The resistor 15b is connected between the collector and emitter of the transistor 15h, and the emitter of the transistor 15h is connected to the negative output terminal of the auxiliary power supply 12.

Based on the above configuration, the operation of the conventional discharge lamp lighting device will be explained with reference to FIG. 2. Note that FIG. 2 shows operating waveforms of various parts of the conventional device.

First, when the commercial AC power supply 1 is turned on, the commercial AC power supply l as shown in FIG. is obtained and input to the transistor inverter 3, and is applied across the harmonic choke coil 5 and the primary winding 6a or 6b between the collectors and emitters of the main switching transistors 7a and 7b. At this time.

The transistor 15h provided in the starting (b) path 15 is OFF.
Therefore, a pulsating DC voltage obtained by dividing this pulsating DC voltage by the resistor IO and the resistor 15b is applied to both ends of the resistor 15b. In each cycle of this divided pulsating DC voltage, the Zener voltage V of the constant voltage diode 15e
Since the transistor 15d is ON during the period Tt from the phase θ exceeding z to the phase θ2, when the negative output terminal of the rectifier 2 is set to zero potential, the terminal voltage of the resistor 15b and the collector-emitter of the transistor 15d are The voltage between them is as shown in FIGS. 2(c) and 2(d), respectively.

here.

Phase θ. If the zero point phase of the voltage of all the above fishing AC power supplies 1 is taken as the zero point phase, then in each cycle of the pulsating DC voltage that is the output of the rectifier 2, the phase θ. to phase θ, and from phase θ2 to phase θ. In both sections of section T in 1,
Resistance 10 and resistance 9% from the positive output end of the rectifier 2 above
Furthermore, base current is supplied to main switching transistors 7m and 7b via base resistors 8a and 8b. At this time, due to a slight imbalance in the circuit, a collector current begins to flow to either one of the main switching transistors 7&, 7b, and the transistor inverter 3 performs a self-oscillation operation due to the action of the base winding 1i6c, causing the output voltage to decrease. For example, each winding of 6 has a frequency of 20 KHz to 40 KH.
As shown in FIG. 2(e) at about z, a high frequency voltage waveform having a dotted envelope is generated. That is, the oscillation is fully performed in the interval T and the interval T, and the oscillation is stopped in the interval T.

The DC voltage that is the output of the auxiliary DC power supply 12 smoothed by the base resistor 8& and the main switching transistor 7
The voltage is applied between the collector and emitter of the transistor 13 via either the base and emitter of the transistor 1 or the base and emitter of the base resistor 8b and the main switching transistor 7b.

However, one end of the resistor 14 connected to the base of the transistor 13 is connected to the transistor 1 which is turned on in the section T.
5d, so if the negative output terminal of the rectifier 2 is set to zero potential, the transistor 13
The voltage between the emitter of the main switching transistors 7a and 7b and the emitter of the main switching transistors 7a and 7b has a voltage waveform as shown in FIG. Since the base t#L becomes zero in the interval T, a voltage waveform as shown in FIG. 2(e) is generated in each winding of the output transformer 6.

In addition, in order to prevent the fluorescent lamp 4 from immediately lighting up due to the high frequency voltage generated in the output winding 6e, the phase θ or the phase θ is set.

At this time, the voltage applied to the preheating electrodes 4a, 4b is set to an appropriate value, for example, 3.8V to 4.8V. Electrode winding 6f, 6g' so that ZVa degree? Set it. With such a configuration, the preheating electrodes 4a and 4b operate first to perform preheating without turning on the fluorescent lamp 4 for a certain period of darkness after the commercial AC power source 1 is turned on.

By the way, the main switching transistor 7 is connected from the output end of the rectifier 2 via the resistor 1O29 and the base resistors 8a and 8bt.
The base tR supplied to a and 7b is in the interval T as described above.
, and in section T, this is to start the oscillation of the transistor inverter 3, and although it is designed to be a small current, a sufficient pace current is supplied from the auxiliary DC power supply 12. Therefore, both switching transistors 'la and 7b operate in the saturation region.

On the other hand, a capacitor 15f provided in the starting circuit 15 is charged from the auxiliary DC power supply 12 via a resistor 15e'e, but when the voltage of this capacitor 15f exceeds the Zener voltage of the voltage regulator diode 15g, the transistor 15h turns ON. The terminal voltage of the resistor 15b is the constant voltage diode 15
V) The above transistor 15d is below the Zener voltage of c.
Turn tiOFF. As a result, the voltage between the emitter of the upper ml transistor 13 and the emitters of the main switching transistors 7a and 7b has a voltage waveform as shown in FIG. 2(g). In other words, the auxiliary DC power supply 1
2 supplies sufficient pace current to the main switching transistors 7m and 7b, and a high frequency voltage (hereinafter referred to as no-load voltage) is generated in each winding on the secondary side of the output transformer 6 as shown in FIG. 2(h). do. Here, the above commercial AC power supply 1
The operation up to this point after turning on is hereinafter referred to as preheating operation.

In the conventional device as described above, when the fluorescent lamp 4 is turned on,
The rung current and lamp voltage are shown in Figure 2 (i).

As shown in U), the waveform has a dotted envelope 2, and since each winding on the secondary side of the output transformer 6 is also a leakage type transformer, the waveform is similar to that of the lamp voltage. In FIG. 2(j), phase θ indicates the re-ignition phase of the fluorescent lamp 4, and this lamp voltage value is compared with the no-load voltage value as shown in FIG. 2(h). Therefore, it is possible to design the voltage generated at the preheating chamber 5 poles 4a, 4b to be approximately the same as or higher than the voltage during the preheating operation.

As described above, in the conventional discharge lamp lighting device, after the commercial AC power supply 10 is turned on, the electrode is preheated for a certain period of time, and then the warning light is turned on to preheat the electrode 4a.

The aim was to reduce damage to the 4b and extend the life of the warning light.

However, 1, for example, although a normal warning light 4 is set in the appliance, the ambient temperature or power supply voltage when the power supply 1 is turned on is too low, or one of the two preheating electrodes 4a and 4b installed There may be cases where the warning light 4 does not light up even after the above-mentioned preheating operation because only the electrodes are not set properly, and in this case, the above-mentioned no-load voltage remains generated in the above-mentioned electrode windings 6f and 6g. last. Therefore, it differs depending on the above-mentioned phase θ or the set value of the phase θ.

Considering that the warning light 4 is not turned on during preheating operation, the no-load voltage value of ρ is more than twice that of preheating operation,
For this reason, an overcurrent flows through the preheating electrodes 4a and 4b, causing the warning light 4 to turn black in a short period of time. There was a problem with light lamp 4 being damaged.

This invention was made in order to eliminate the drawbacks of the conventional device as described above.If the warning light does not light up during the preheating operation after the power is turned on, the voltage value generated in the electrode winding is changed to the preheating operation. It is an object of the present invention to provide a discharge lamp lighting device that can suppress the above-mentioned voltage value generated in the pole winding to less than several times higher than the same value as the conventional device.

Hereinafter, one embodiment of the present invention will be explained with reference to FIGS. 3 and 4.

FIG. 3 is an electric circuit diagram showing an embodiment of the present invention,
FIG. 4 shows the operation waveforms of each part in FIG. 3. In the figure, the same reference numerals as in FIGS. 1 and 2 indicate the same or equivalent parts, and detailed explanation thereof will be omitted.

In FIG. 3, the difference from the configuration in FIG. 1 is that the collector of the transistor 15d is directly connected to the base of the transistor 13 without using the resistor 14. In contrast, in FIG. The collector of the transistor 15d was connected to the contact point between the resistor 9 and the resistor 14.

Based on the above configuration, the operation of an embodiment of the present invention will be explained.

First, when the commercial AC power supply l is turned on, Fig. 4 (JL)
The AC voltage shown in Fig. 4(b) is rectified by the rectifier 2.
A DC voltage as shown in is output. On the other hand, during the preheating operation, the transistor 15d is 0FF in the sections T, , T.
Since L is ON in the section T2, the collector-emitter voltage of the transistor 15d to which the DC voltage is applied is the same as in the section T, as shown in FIG. 2(d) above.
, T, is 0FFL, and it is ON in the section T, so in Fig. 4 (
A voltage waveform as shown in d) is obtained. Therefore, the interval T,,T
, since the transistor 15d is OFF, the auxiliary DC power supply 12 is connected to the main switching transistors 7a and 7b.
Since sufficient base current is supplied from
At s, a high-rise light voltage as shown in FIG. 4(e) is generated. On the other hand, in section T, the collector of the transistor 15d, which is turned ON in this section, is connected to the base of the transistor 13, so that the auxiliary DC is connected to the main switching transistors 7a and 7b as in the conventional device of FIG. No base current is supplied from the power supply 12, but the resistor 10
,9. A base current is supplied from the output end of the rectifier 2 via base resistors 8a and 8b. As a result, the transistor inverter 3 oscillates even in the interval T, and each secondary winding of the output transformer 6 is connected to the interval T! In interval T,
A high frequency voltage as shown in FIG. 4(e) is generated which is lower than the peak voltage of ,T. However, in this case, K is insufficient to turn on the warning light 4 with the high frequency voltage generated in each winding on the secondary side of the output transformer 6 in section T, but preheating 1 [
The resistance values of the resistors 9 and 10 are set so that the poles 4a and 4b can supply base current sufficient to preheat the main switching transistors 7a and 7br. Therefore, in section Tt, since the transistor 15d is ON, the main switching transistors 7m and 7b operate in the active region, and each winding on the secondary side of the output transformer 6 is
) is generated, but the transistor 1
3 emitter and main switching transistors 7a, 7
As shown in FIG. 4(f), the emitter-to-emitter voltage Vi of b is in the interval T! becomes zero potential.

As explained above, in the conventional device shown in FIG.
The oscillation operation is also performed in the main switching transistor 7a, and the magnitude of the oscillation is determined by the main switching transistor 7a.

It is determined by the base current flowing through 7b, but it is obvious that it is influenced by the size of resistor 9.10 provided in the circuit of FIG.

FIG. 4 (to) shows, similar to that shown in FIG. 2 (b), that the voltage of the capacitor 12b charged by the auxiliary DC power supply 12 exceeds the Zener voltage of the constant voltage diode 15g, Transistor 15dtOFF
This is the operating waveform of the voltage between the emitter of the transistor 13 and the emitters of the main transistors 7a and 7b when At this emitter-to-emitter voltage, sufficient base current is supplied from the auxiliary DC power supply 12 to the main switching transistors 7g and 7b, and each winding on the secondary side of the main cadence 6 receives the voltage shown in FIG. 2 above. As a result, a no-load voltage as shown in FIG. 4(h) is generated.

Therefore, according to an embodiment of the present invention, the voltage value of the electrode windings 6f and 6g during preheating operation is set to the same level as in the case of the conventional device shown in FIG. By setting such that , at this time, the voltage value generated in the electrode windings @6f, 6g is compared with the above-mentioned Fig. 4 (e) and as is clear, the voltage value generated during the above-mentioned preheating operation is about several times higher. can be suppressed to For example, phase θ8. θt-t/, C, r
If you set it to ac+), it will increase by about 30%. Therefore, in this embodiment, it is possible to prevent the occurrence of overflow in the preheating electrodes 4a, 4blC.

Note that FIGS. 4(i) and 4(j) show the same operating waveforms of the lamp current and lamp voltage as in FIGS. 2(i) and (j>, respectively, when the fluorescent lamp 4 is turned on.

By the way, in one embodiment of the present invention, the h electrode winding ll1
The voltage values generated at 16f and 6g are designed to be the same as the conventional device as described above, but the preheating electrode 4 after the fluorescent lamp 4 is turned on is
a. To set up 4bi properly.

Transiro g before and after lighting the fluorescent lamp 4,
An impedance such as a coil or a capacitor may be inserted in series with the preheating electrode 4b to form a total preheating device.

Furthermore, the base current may be supplied to the main switching transistors 7a and 7b only from the output terminal of the rectifier 2, and the base current value may be changed between the sections T, , T and the section T. Furthermore, when using an auxiliary power source, it is not limited to the one taken from the output transformer 6 as in the above-mentioned embodiment.
For example, it is clear that the power may be taken directly from the commercial AC power supply l.

Furthermore, the input voltage to the transistor inverter 30 may be a pulsating DC voltage as shown in FIG.

As explained above, the present invention provides a discharge lamp lighting device including a discharge lamp and a high frequency generator having a plurality of preheating electrodes, in which at least one of the preheating electrodes is set normally. Even if the discharge lamp does not turn on for some reason after the preheating operation is completed, it is possible to prevent overcurrent from flowing to the preheating electrode, and as a result, the discharge lamp may turn black in a short period of time, or in some cases, This has the advantage of being able to prevent damage and reduce costs by extending the lifespan.

[Brief explanation of the drawing]

Figure 1 is an electric circuit diagram showing the entire conventional discharge lamp lighting device, Figure 2
The figure is an operation waveform diagram showing the operation 2 of each part in Figure 1, Figure 3 is a diagram equivalent to Figure 1 showing an embodiment of this invention, and Figure 4 is a diagram equivalent to Figure 2 showing the operation of each part in Figure 3. be. l... Commercial AC power supply, 2-... Rectifier, 3... Transistor inverter, 4... Fluorescent lamp, 4a, 4b°°
・Preheating electrode, 5...Harmonic choke coil, 6...
Output transformer, 7a, 7b... Main switching transistor, 8a, 8b... Base resistor, 12... Auxiliary DC power supply, 13.15d, 15h... Transistor,
15-... Starting circuit, lse, tsg... Constant voltage diode. 15f... Capacitor. Agent Shin Kuzuno −

Claims (1)

[Claims] (1) High-frequency generator that includes a commercial AC power supply, a rectifier that rectifies the AC voltage output from the commercial AC power supply, and a leaky transformer that converts the pulsating DC heavy pressure that is the output of the rectifier into high-frequency voltage. with equipment. The above-mentioned high-frequency generator includes: a discharge lamp with preheating electrodes that are turned on by inputting the high-frequency voltage; a preheating device with electrode windings on the secondary side of the transformer that preheats the preheating electrodes of the discharge lamp; and the high-frequency generator. In a discharge lamp lighting device comprising a switching semiconductor device, a starting circuit that starts all of the switching semiconductor devices under predetermined conditions, and an auxiliary DC power supply that supplies a control current to the switching semiconductor device, the commercial AC power source For a predetermined period from when the DC voltage is turned on, in each cycle of the DC voltage, the switching semiconductor device of the high frequency generator is operated in the saturation region in the section where the DC voltage is lower than the preset DC voltage value, and in the active region in the section where it is higher. A discharge lamp lighting device characterized in that, by operating the discharge lamp, a preheating electrode of the discharge lamp is preheated without completely lighting the discharge lamp.