JPS59103298A - 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 method for preheating electrodes at the time of starting the device and for lighting the discharge lamp.

FIG. 1 is a circuit diagram showing a conventional discharge lamp lighting device.

In Figure 1, (1) is a commercial AC power supply, (2) is a rectifier that covers all inputs of this commercial AC power supply (1) and rectifies the AC voltage, and (3) is a pulsating current that is the output of this rectifier (2). A self-oscillating push-pull transistor inverter converts the direct current voltage into a high-frequency voltage, (4) is a filament (4a) that lights up by receiving the high-frequency output voltage of this transistor inverter (3), and (4b) a firefly that flashes. light lamp, (5) is the filament (4a), (41)
) is connected in series with a bidirectional three-terminal control element (hereinafter referred to as TRIAC), which is a semiconductor control element (61 is a semiconductor control element that turns on the TRIAC (5) completely from the time when the commercial AC power supply (1) is applied. Tryout after a certain period of time set by
5) is a timer circuit for turning off the control signal, and (7) is a power transformer that receives the AC power source (1) as an input.

Next, the entire configuration of the transistor inverter (31) will be explained.

(8) is a harmonic choke coil, and the positive output end of the rectifier (2) is connected via this harmonic choke coil (8) to a pair of primary windings M (9a) of a leakage type output transformer (9).
).

(9b), while the rectifier (2)
The negative output terminal of is connected to a pair of main switching transistors (1
0a) and (10b).

This main switching transistor (10a), (1
The base of ob) is connected to both ends of the base winding (90) of the output transformer (9), and is connected to the rectifier α2 via base resistors (11a) and (11b) 2, respectively.
connected to the positive output end of the This rectifier α rectifies the AC output voltage of the secondary winding (7b) of the power transformer (7).

The negative output terminal is connected to the negative output terminal of the rectifier (2).

The main switching transistors (10a), (1
The collectors of the primary windings (9a) and (9
A resonant capacitor (13) is connected between the collectors of the amphibonic switching transistors (10a) and (1ub).

Further, the output lance (9) is connected to the fluorescent lamp (
41' has an output winding (9d) k for lighting, and at both ends there is a frame for a fluorescent lamp (4) (4a)
, (4b) are connected on one side. Firamen)
The other ends of each of (4a) and (41j) are connected to the T1 terminal and T2 terminal of the triac (5), respectively.

The timer circuit (6) also has a capacitor α4. resistance(
15! , 7' programmable unidirectional transistor (hereinafter abbreviated as PUT) αe, resistor α7),
Q81, and the contacts of capacitor α (a) and resistor (17) are connected to diode 9. The secondary winding (7C) of this rectifier Qυ stripped main power transformer 7 is connected to the positive output of the rectifier 5 (21+) through a resistor (2I'i)
The AC output voltage is fully rectified, and the negative output terminal is connected to the resistor 9. αl is connected to the cathode contact of PUTOe, and at the same time is connected to the emitter of the transistor (22).The base of this transistor (22) is connected between the contacts of the resistor αη, through a resistor. , the collector is connected to the gate of the trybook (5).

A smoothing capacitor 0 is connected to the output of the rectifier (21).
4) is connected. Further, the anode of the diode 1 is connected to the T1 terminal of the triac (5).

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.

When the commercial AC power supply (1) is turned on, the AC voltage of the commercial AC power supply fil as shown in Figure 2(a) is rectified by the rectifier (2), and the pulsating DC voltage as shown in Figure 2(b) is generated. The voltage enters the transistor inverter (3) and passes through the harmonic choke coil (8) and the primary winding (9a) or (9b)' to the main switching transistor (10a), (
10b) is applied between the collector and emitter. At the same time, the AC voltage generated in the secondary winding M (7b) of the power transformer (7) is rectified by the rectifier αa, and the positive output terminal of the rectifier Q2 is connected to the base resistor (11a) or the base resistor (11b)' ( The base current is supplied to the main switching transistors (10a) and (10b) through i7.Then, due to a slight imbalance in the circuit, the collector current flows to one of the main switching transistors (10a,) and (10b). Starting base winding (9
Due to the action of C), the transistor inverter (3) performs self-oscillation operation.

Each winding of the output transformer (9) is connected as shown in Fig. 2 (C).
For example, a high frequency voltage of about 20 KHz to 50 KH2 is generated (the dotted line indicates the high frequency envelope).

The following also follows).

On the other hand, at the same time as the commercial AC power supply (1) is turned on, the AC voltage generated in the secondary winding (7C) of the power transformer (7) is rectified by a rectifier (2υ) and smoothed by nine capacitors, and this DC voltage is The voltage is applied to the timer circuit (6) via the diode (11'), and the fluorescent lamp (4) is not fully lit for t1 seconds after the power is turned on with a CR time constant.

The filaments (4a), (41)) constitute two preheating circuits. In other words, when the power is turned on, P UT (
If the date voltage of lG is higher than the anode voltage (, PUT(1
61 is off and the rectifier 5 (2+
) from the positive output end of resistor 20. Diode slope, resistance side,
The base current is supplied through t23i, and the transistor (
2) is turned on. Therefore, since the triac (5) is turned on by being supplied with gate current, the above-mentioned output voltage (
9) - output winding (9d) - filament (4a) - triac (5) - filament (4b) - output winding (9d)
) current flows through the closed circuit of filament (4a), (
4b) f Preheat.

Then, t1 seconds after the power is turned on (for example, about 1 to 3 seconds), due to charging of capacitor α4, the gate voltage of PUTαe becomes lower than the anode voltage, and PUT(le is turned on and transistor 2 is turned off. , at phase φ1 shown in FIG. 2(0), no gate current flows through the triac (5) (and the triac (5) attempts to turn off).

Then, since the high-frequency current flowing through the triac (5) becomes zero, there is a point in time when the holding current is lower than the holding current, which is one of the conditions for turning off the triac (5), and this is satisfied.
Another condition is that the rising slope (firm) of the voltage immediately after that is very thick (.

The performance of a normal triac (6 to 10 V/use) is insufficient, and the triac cannot be turned off and remains on. In the next cycle, the same condition will be met and the on state will continue.

However, as the phase approaches φ1 (as the triac (5)
The triac (5) is turned off at the phase when the current flowing through the triac (5) becomes less than the holding current and becomes less than the withstand capacity of the triac (5). Therefore, output (9)
The high frequency secondary voltage generated in the output winding (9d) of is applied to the fluorescent lamp (4), and the fluorescent lamp (4) is turned on. The waveforms of the lamp current and lamp voltage of the fluorescent lamp (4) after lighting are as shown in FIGS. 2(d) and 2(e), respectively. Therefore, after the fluorescent lamp (4) is turned on, the voltage applied to the triac (5) has the lamp voltage waveform shown in Fig. 2(e).1 Rising slope (-) of the blocking voltage of a normal triac =
1oo~200V/ is actually a
It is possible to satisfy the usage requirement and keep all the fluorescent lamps (4) lit stably.

By the way, in the conventional discharge lamp lighting device as described above, the voltage input to the transistor inverter (3) is a DC voltage 1, for example, a voltage rectified by an AC voltage full rectifier of an AC power supply and smoothed by a smoothing capacitor, or In the case of common knowledge batteries, etc.

Due to the characteristics of the triac (5) described above, even if the gate current stops flowing and the current flowing to the triac (5) becomes less than the holding current, the rising slope of the voltage immediately after that (')
Since there is no phase where C is small, the triac (
5) had the disadvantage that it could not be turned off.

This invention eliminates the above drawbacks, and by stopping the oscillation of the inverter for a predetermined period of time after the control signal of the triac is turned off, it is possible to sufficiently preheat all electrodes of the discharge lamp even when the input to the inverter is DC voltage. It is an object of the present invention to provide an entire discharge lamp lighting device capable of lighting a discharge lamp by surely turning off a triac, which is a semiconductor control element.

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, and FIG. 4 is a waveform diagram for explaining the operation of this circuit diagram.

In FIG. 3, (1) to (1) are completely the same as the conventional device. (c) is a smoothing capacitor connected to the output end of rectifier (2), (c), @, @ are smoothing capacitors connected to the output end of rectifier Q2.

This is a zero resistance oscillation temporary stop control circuit. In this oscillation temporary stop control circuit (c), the anode of the diode wire is connected to the positive output terminal of the rectifier (c), and the cathode is connected to one end of a parallel circuit consisting of a capacitor (to) and a resistor (31). The other end is connected to the anode of the thyristor (32),
The cathode is connected to the negative output of the rectifier. Also, one end of the resistor (63) is connected to the positive output end of the rectifier, the other end is connected to the capacitor (64), and the other end of the capacitor (34) is connected to the negative output end of the rectifier (to). The resistor (33) and capacitor (64)
) is connected to the cathode of a constant voltage diode (35), and the anode is connected to the gate of the thyristor (32).

Next, the operation of the discharge lamp lighting device configured as described above will be explained based on the drawings. FIG. 4 is a waveform diagram for explaining the circuit operation.

When the commercial AC power supply (1) is turned on at time (to).

A DC voltage smoothed by the action of a smoothing capacitor (2!9) is input to the transistor inverter 131, and the circuit operates in the same manner as described in connection with the conventional device.

The output winding (94) of the output transformer (9) is shown in Figure 4 (e).
), a high frequency voltage is generated. At the same time, due to the circuit operation of a timer circuit similar to that described in connection with the conventional device, a gate current flows through the triac (5) as shown in FIG. 4(a), and the triac (5) is turned on. Filament (4a), (4b) of fluorescent lamp (4)
Preheating current begins to flow.

On the other hand, at the same time as the current is turned on, a DC voltage obtained by smoothing the output of rectifier α2 with a smoothing capacitor (a) is applied to the oscillation pause control circuit (to), and is passed through the resistor (33)' to the capacitor (3). As shown in Fig. 4 (b), charging begins. At this time, the cyrisk (62) is off because no gate current flows.

Then, due to the action of the timer circuit (6), the gate current flowing through the triac (5) is turned off at time t1, so the triac (5) attempts to turn off.

As described above, the triac (5) cannot be turned off because the voltage rising slope v (, E ) c does not become less than the withstand voltage immediately after the current flowing through the triac (5) becomes less than the holding current. However, at 1 hour t2, the voltage of the capacitor (34) changes to the constant voltage diode (35
) Zener voltage ■z exceeds thyristor (32) turns on.

The capacitor (to) begins to be charged as shown in FIG. 4(C). Therefore, the main switching transistor (10a)
.

The base current supplied to (1ob) is shown in Figure 4 ((1ob)
), the transistor inverter (3
) stops oscillating, and the preheating current flowing through the triac (5) stops flowing, so the triac (5) turns off. Then, in one hour t3, charging of the capacitor (to) is completed, and the main switching transistor (10a), (1
The base current begins to flow through 0b), the transistor inverter (3) oscillates again, and the high frequency voltage generated in the output winding (9d) lights up the fluorescent lamp (4). in this case.

(4a),
The resistance (55) should be short enough that the temperature of (4b) does not drop too much.

By selecting the OR time constant of the capacitor (64), it is possible to turn on all the fluorescent lamps (4) while the timer members (4a) and (4b) are heated.

By the way, the timer circuit (6) of the present invention need not be limited to that of this embodiment (as long as the gate current can flow through the triac (5) for a predetermined period of time after the power is turned on (or one oscillation). There is no need to limit the temporary stop control circuit (c) to that of this embodiment.

There is no need to insert it into the base circuit, and the triac (5
) after the gate current of the transistor inverter (
Any device that can stop the oscillation in 3) for a short fixed period of time is sufficient. On the other hand, the input of the transistor inverter (3) does not have to be a completely smoothed DC voltage.

As described above, the present invention can be applied even when the voltage applied to the inverter is a smoothed TK current voltage.

By adding a complete oscillation pause control circuit consisting of simple circuit components to a conventional device, it is possible to reliably light the discharge lamp after the entire filament of the discharge lamp has been heated after the power is turned on. .

[Brief explanation of drawings]

FIG. 4 is a circuit diagram of a discharge lamp lighting device showing an embodiment of the present invention, and is a waveform diagram for explaining the circuit operation of FIG. 3. I like the figure, +10'! , commercial AC power supply, +21.
(13, C111'! Rectifier NL ta+ is a transistor innocent, (4) is a fluorescent lamp, (5) is a triac, (6) is a timer circuit, (7) is a power transformer, (
9) is output cadence, (10a), (10b)
is the main switching transistor, and @ is the oscillation temporary stop control circuit. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Shin Kuzuno −

Claims (1)

[Claims] An inverter having a DC power supply, an output transformer that converts the DC voltage into a high-frequency voltage, a preheated cathode discharge lamp connected in series with the output winding of the output transformer, and a filament of the discharge lamp connected in series with the output winding. A semiconductor control element is connected in series to a circuit, and a control signal of the semiconductor control element is turned off after a certain period of time after turning on all of the semiconductor control elements and setting a full preheating current to the filament of the discharge lamp from when the commercial AC power is turned on. In the discharge lamp lighting device comprising a timer circuit, the oscillation temporary stop control circuit causes all of the discharge lamp lamps to light up by stopping the oscillation of the inverter for a predetermined period of time after the control signal of the semiconductor control element is turned off. A discharge lamp lighting device having the following features: