JPS61101996A - Discharge lamp lighting apparatus - 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] [Field of Industrial Application] This invention relates to a device for lighting a discharge lamp using a high-frequency generator that generates high-frequency power, and particularly to a device for lighting a discharge lamp by controlling the high-frequency generator using a dimming signal to dim the discharge lamp. The present invention relates to a discharge lamp lighting device.

[Conventional technology]

The discharge lamp is lit at a high frequency through an output transformer of a high frequency generator such as an inverter, and the output of the inverter is controlled at a cycle longer than the same wave number of the lighting.

Methods of controlling light have been known for a long time.

However, even after trying to completely stop the inverter's operation, the inverter's output transformer does not respond to the dimming signal.
The stored energy remains.

The discharge is maintained for a considerable period of time.

Figure 3 shows this situation, and the dimming signal a is (A).
Even when the light is turned off (period Ts), the secondary voltage (b) of the output transformer remains for a period as shown in +tO.

Output remains due to accumulated energy.

This is inconvenient because it causes flickering when trying to deepen the dimming level, so a device to improve this problem was developed in Japanese Patent Laid-Open No. 5! No. 1-99697 proposes an apparatus shown in FIG.

In the device shown in Figure 2, (1) is a DC power supply, (2) is an inverter, (3) is a discharge lamp, (5) is an output transformer,
(SS) is the secondary winding, (5K)ii auxiliary winding, 041
is a full wave rectifier circuit.

(9a) and (9b) are switching transistors of the inverter, transistors for controlling in+l'i dimming.

Like the above? In the configured device, the inverter (
21 is the secondary winding (5B) of the output transformer (5), which does not self-oscillate due to the action of base feedback -SL%+ (5B).
) generates a secondary voltage and lights up the discharge lamp (3). Here, the base currents of transistors (9a) and (9b) are:
The auxiliary winding (5K) Ic is supplied by rectifying the generated voltage. here.

When a dimming signal as shown in FIG. 3(A) is applied to the transistor @U, the transistor 141I is turned off during the lighting period of +T2, and the inverter (2) generates an output voltage.

Next, during the light-off period T3, the transistor f4D is at O
N, inverter +21 switching transistor (
When the base current supply to 9a) and (9b) is stopped, the energy stored in the output transformer (5; ; and consumes energy.Thereby, the secondary voltage of the output transformer (5) can be lowered more quickly than in the conventional device.

[Problem that the invention seeks to solve]

However, in the device shown in Fig. 2 as well, the resistor ff31 is used to configure the tamping circuit, so it is difficult to respond to cases where the secondary voltage needs to be lowered more quickly. There were problems such as an attempt to increase the allowable current of a full-wave rectifier circuit (141) using a full-wave rectifier circuit (141) would result in an increase in price.

[Means for solving problems]

This invention uses a dimming signal to stop the operation of the inverter, and a trigger means to short-circuit the output of a short-circuit winding provided in the output transformer of the inverter by using a bidirectional thyristor called a triac (CINI). Therefore, it is a device that rapidly lowers the secondary voltage of the output transformer and quickly stops the discharge of the discharge lamp.

[Operation of the means to solve the problem] Since the short-circuit winding, which is the winding provided in the output transformer, is short-circuited, the magnetic circuit in which this short-circuit winding is installed (the output voltage of each winding above is naturally After that, the inverter completely stops working, and the triac no longer conducts current, turning it off.Thus, the next time the light is turned on.

The inverter generates an output and lights up the discharge lamp. 〇 [Embodiment] Fig. 1 shows an embodiment of the device according to the present invention.
161, and this charge is supplied as a base current from the resistor aJ to the switching transistors (9a) and (9b) through the base resistors (10a) and (10b).The transistor Ill is connected to the terminal a. Resistance from (4
? A dimming signal as shown in FIG. 4(a) is applied through the light source. (5N) is a short-circuit winding provided in the output transformer (5), and a short-circuit current flows through the triac (171) as shown in the diagram. Resistor a11.■, capacitor ■, diode file, +1 !IFi,
) This circuit serves as a means for generating a trigger signal for the light aη, and generates a trigger pulse with an inversely appropriate time width from the dimming signal. Note that other than the above, this device is the same as the conventional device shown in FIG.

In the device configured as above, an inverter (
2) operates like a 1N controller and lights up the discharge lamp (3). Now, assume that the lighting period is T2 in FIG. 4(a). (b) Is triac 0? 'l trigger signal, (
/→ is the voltage of the collector winding (5C) of the output transformer (5).

In this way, when the state shifts from the lighted state to the period T3 where the light is off, the transistor I is turned on by this dimming signal, and the switching transistor (9a) is turned on.
, (9b) stops supplying base current. here,
The period determined by the resistor @, capacitor ■, etc., that is +T4
Since a trigger signal with a pulse width of

Immediately, the collector winding (5C) becomes as shown in Fig. 4H (the output voltage disappears. Therefore, the secondary voltage of the output transformer (51) can also be reduced. After this, the triac αη
turns off because there is no output voltage of the shorted winding (5N), so there is nothing wrong with the 9th order lighting rcFi. In this way, the discharge lamp can be smoothly dimmed by the repeatedly generated dimming signal.

Here, the principle of using the triac Q'rl, which is important to this invention, will be clarified. FIG. 5 shows, as an example, the surge on tic of a small capacity (3A) triac. This is quoted from ``81 Mitsubishi Semiconductor Data Book, Power Semiconductor, Stack Edition (K in Seibundo Shinkosha) 5-3. The period during which the high frequency output of the inverter is short-circuited is short, and the characteristic of the triac having a large surge-on current is very advantageous in selecting an element.

Also, as is well known, triacs are originally commercial ACs.
It is used for phase control of \IL.

The turn-off time is long when used at high frequencies.

It cannot be turned off and remains ON once triggered.

In the device of this invention, since the inverter (2) stops operating, it would be advantageous if it could be turned off during this time (5 points).

Next, other applications of the device of this invention will be described.

In the embodiment, the short-circuit winding was provided on the primary side of the chemical quadrant, but it may also be provided on the secondary side, and the auxiliary winding (5K) is
Use it as it is as a short-circuit winding (auxiliary winding M (5K)
You can also use each winding of the inverter as is (by connecting a triac between the terminals of the inverter).

The trigger signal means of the triac is not limited to the embodiments, and may be modified as appropriate, depending on the type of triac.
A trigger pulse with a short width may not be generated (although it may have a pulse width of the same length as the dimming signal, as long as it can be operated with a signal similar to the dimming signal).

Discharge lamp (sin is an electrode that requires heating (3a), (3b)
If the lamp has the following characteristics, an appropriate preheating means may be used, but this is not applicable only to the fourth fluorescent lamp of the present invention.

Similarly, the inverter (2) is not limited to the one in the embodiment, but it may be sufficient as long as it can turn on the discharge lamp via the chemistries and control the output of the discharge lamp by stopping the operation of the inverter. Therefore, the chemistries are not leakage transformers (they may further include a discharge lamp current limiting impedance).

In the explanation of the example, the operation of the inverter is stopped.
(Although the base current of the switching transistor of the inverter is cut off as a means to stop the operation of the inverter, the operation of the inverter may be stopped by a method other than cutting off the base current. 3: No special equipment is required as long as it is suitable for lighting.

Only one discharge lamp is required (even one that lights two or more lamps is fine)
This is a moot point.

〔Effect of the invention〕

As described above, according to the present invention, when the dimming signal is stopped, the triac is used to short-circuit the short-circuit command line provided in the catalytic converter, so that the secondary voltage of the catalytic converter is quickly lowered, and the inverter, etc. Because the high frequency generator stops working.

Promptly stop the discharge of the discharge lamp and stop the operation of this high frequency generator to prevent the triac.

It also has the advantage of eliminating the need for a special commutation circuit for turn-off.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram showing a conventional device, Fig. 3 is an explanatory diagram of its operation, and Fig. 4 is an explanation of the operation of the device shown in Fig. 1. FIG. 5 is an explanatory diagram of the characteristics of the triac. In the figure, (1) is a DC power supply, (2j is an inverter that is a high frequency generator, (3) is a discharge lamp, (5) is a chemistries, (5N) is a short-circuit winding, (171 is a triac, Q
L Qcl, @. r21+ and @ are a diode, a capacitor, and a resistor as trigger means.

Claims (1)

[Claims] A discharge lamp lighting device in which the operation and stop of a high-frequency generator that generates high-frequency power is controlled by a dimming signal for operation and stop, and the output transformer of this high-frequency generator controls the amount of light emitted by the discharge lamp. The output transformer further includes a short-circuit winding provided in the output transformer, a tri-ax for short-circuiting the output of the short-circuit wind, and a trigger means for triggering the tri-ax in synchronization with a stop signal of the dimming signal. Characteristic discharge lamp lighting device.