JPS61135096A - Discharge lamp dimmer - 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] 〔Technical field〕 The present invention relates to a discharge lamp dimming device.

[Background technology]

In conventional discharge lamp dimmers, the dimming means include, for example: ■ Means by controlling the phase of an AC power source ■ Means for adjusting the voltage applied to the discharge lamp ■ Means for adjusting the oscillation frequency of an inverter to limit the light Means for adjusting diversion/impedance ■ For example, there is a means for adjusting the current-limiting impedance by using a saturable inductance and adjusting the inductance value.

However, in the phase i1i control (■) and the applied voltage adjustment (■),
When dimming to a low level, it becomes difficult to keep the discharge lamp lit, and the discharge lamp goes out.

This caused the problem of flickering.

In addition, in the oscillation frequency adjustment described in (2), it is necessary to adjust the frequency over a wide range (for example, several tens of kilohertz to several hundred kilohertz), which poses problems such as the control section becoming complicated and expensive parts being required. .

In addition, when a saturable inductance is used as the current-limiting element of a discharge lamp, as in (■), it is necessary to adjust the inductance value over a wide range in order to dim the light to a low level, and the saturable inductance is There was a problem with increasing the size.

Furthermore, deep dimming at low levels may cause malfunctions in television receivers and the like due to optical remote control interference, and may increase the level of radiation noise generated from discharge lamps.

[Object of the invention] The object of the invention is to solve the problems of the conventional example,
A compact and inexpensive one-circle discharge lamp lighting device with good dimming stability down to low levels! U In'・It's something to do.

[Disclosure of the invention]

The discharge lamp dimmer of the present invention includes a rectifying and smoothing section that converts an AC power supply voltage into a DC voltage, an inverter section that converts the DC output voltage of the rectifying and smoothing section into a high-frequency voltage, and a connection of this inverter section to a discharge lamp. the current limiting element, the first dimming means of the type that does not change the oscillation frequency of the inverter section, the second dimming means of the type that changes the oscillation frequency of the inverter section, and the j-th dimming means for dimming up to a certain level. and a dimming control section that operates the second dimming means for dimming to a deeper level.

In this configuration, to be more specific about the first dimming means that does not change the oscillation frequency of the inverter, the first dimming means includes: (1) means for controlling the phase of the AC power supply; These include means for adjusting the DC output voltage of the smoothing section using a chopper or the like, and (iii) means for adjusting the impedance of the current limiting element.

According to the above structure of the present invention, there is the following effect.

For dimming up to a certain level, the first dimming means performs dimming without changing the oscillation frequency of the inverter, and for dimming at a deeper level, that is, at a lower level, the second dimming means By controlling the frequency, it is possible to prevent the discharge lamp from turning off or flickering during low-level dimming.

In particular, when adjusting a current-limiting element such as a saturable inductance using the first dimming means, the voltage applied to the discharge lamp can be kept fairly constant, which prevents it from turning off during low-level dimming. The effect is large.

To+ 71) Since the optical means is divided into a first dimming means that does not change the oscillation frequency of the inverter section and a second dimming means that changes the oscillation frequency of the inverter section, it is different from the conventional method. Compared to a configuration in which a single dimming means performs deep dimming, the entire device can be made smaller and less expensive.

By performing the dimming at a low level by frequency control using one stage (second dimming), it is possible to alleviate malfunctions of television receivers and the like due to optical remote control interference.

Furthermore, the level of radiation noise generated from the discharge lamp can be reduced.

Embodiments Two examples of embodiments of the basic configuration of this invention are shown in FIGS. 1 and 2.
As shown in the figure.

In these figures, 1 is an AC power supply, 2 is a voltage control section,
3 is a rectifying smoothing part, 4 is an inverter part, 5 is a current limiting element, 6
7 is a discharge lamp, 7 is a dimming control unit, 7A is a first dimming means, 7
B is a second dimming means.

The first dimming means 7A is for dimming without changing the oscillation frequency of the inverter section 4, and the second dimming means 7B is for dimming by changing the oscillation frequency of the inverter section 4. It is.

The dimming control unit 7 operates the first dimming means 7A for dimming up to a certain level, and operates the second tip means 713 for dimming to a deeper level. It is.

In the case of FIG. 1, the first dimming means 7A controls the voltage control section 2, and the second dimming means 7B controls the inverter section 4.

Note that the voltage control section 2 may be provided after the rectifying and smoothing section 3, or may be provided after the inverter section 4.

In the case of FIG. 2, the first dimming control means 7A controls the current limiter @5, and the second dimming control means 7B controls the inverter section 4 in the same manner as in FIG.

A more specific embodiment of this invention will be described based on FIGS. 3 and 4. FIG. 3 is a circuit diagram, and FIG. 4 is a waveform diagram of each part.

In Fig. 3(A), DB is a diode bridge as a rectifying and smoothing section connected to an AC power supply l, In is a half-bridge inverter circuit connected between the output terminals of the diode bridge DB, and T is a primary winding n1. The oscillation transformer Ll connected to the inverter circuit In is the oscillation transformer T
In the discharge lamp circuit DI consisting of the secondary winding n2 and the discharge lamp 6,
There is a saturation inductance uJ with its secondary winding inserted.

The inverter circuit In includes two switching transistors Tr1. Tr2 and two ij4 prevention diodes D
1. It consists of D2 and a voltage dividing capacitor c1°C. The connection point of the diodes D, , D2 and the connection point of the voltage dividing capacitors C, , C2 are connected via the primary winding n1 of the oscillation transformer T.

In FIG. 3(B), E represents a constant voltage power supply and an IC.

and IC, are astable multi-bye breaks made up of general-purpose timer ICs "555'", and IC3 is monostable multi-bye breaks made up of general-purpose timer ICs "555".

The total frequency of the astable multi-by-break IC is l
E resistance R+ is determined by the resistance value of R2, the capacitance of capacitor c3, and the DC voltage to control input terminal 5 pin.

In addition, the astable multi-by-break IG changes the duty ratio and frequency of the output pulse from the output terminal pin 3 depending on the DC voltage input to the control input terminal 5 pin, and the output pulse changes as the DC voltage decreases. The duty ratio becomes larger and the frequency becomes higher.

The DC voltage is adjusted by a variable resistor VR.

rC2 is a T-type flyknob flop, which is an astable multivibrator IC that uses the output pulse of the astable multivibrator C1 as a control signal.

Every time the output pulse of becomes “H” level, the output Q,
Q is inverted.

The Q output and the three bins of the astable multi-by-break IC are connected to the input terminal of the AND circuit AND, and the Q output and the three pins of the astable multi-by-break IC are connected to the input terminal of the AND circuit AND2.

The output terminal of the AND circuit A'ND is the transistor Tr
3, and its collector is connected to the oscillation transformer T
0 connected to the constant voltage power supply through the primary winding of 1
The secondary winding of the oscillation transformer T1 is connected between the base and emitter of the transistor Tr1 of the inverter circuit In.

The output terminal of AND circuit A N D 2 is
It is connected to the base of Tr4, and its collector is connected to the constant voltage power supply via the primary winding of oscillation transformer T2. The secondary winding of the output transformer T2 is the inverter circuit I.
It is connected between the base and emitter of the n transistor Tr2.

Astable multi-by-break IC, to oscillation transformer T1
．． The circuit up to T2 changes the DC voltage to pin 5 of the astable multi-vibration IC from high to low by changing the resistance value of the variable resistor VR from small to large, thereby changing the frequency from low to high. The oscillation frequency of the inverter circuit In is changed from low to high. And inverter circuit In
As the station frequency changes from low to high, the lamp current of the discharge lamp 6 decreases.

The above circuit portion is an example of the "inverter section oscillation frequency changing type second dimming means 7BJ" referred to in the constitution of the invention.

The astable multi-high break IC4 is for determining the oscillation frequency of the insect-stable multi-high break IC3.

The monostable multi-bibreak I03 changes the duty ratio of the output waveform of its output terminal 3 pin by the time constant of the variable resistor VR2 and the capacitor C6.

The base of a transistor 7r6 is connected to this 3 pin, and the transistor T r 5. whose base is connected to this transistor T r 6. Choke L2, diode D3, and capacitor C9 constitute a step-down chopper circuit ch.

Both ends of a diode D4 connected to the capacitor C9 of the chopper circuit channel are connected to the primary winding of the saturable inductance L1.

When the on-duty of the transistors Tr6 and Tr5 changes due to a change in the duty ratio of the output waveform of the monostable multi-bibreak IC, the output voltage of the step-down chopper circuit ch also changes. This adjusts the inductance value of the saturable inductance L1.

In other words, as the resistance value of the variable resistor V R2 changes from small to large, the time constant of the variable resistor vR2 and m+7 dens C6 increases, and the off-duty of the output waveform of the small stable multi-high break tc3 decreases. Therefore, the on-duty of the transistors ``s'' and Tr decreases. Therefore, the output voltage of the step-down chopper circuit ch also decreases, and the control voltage of the saturable inductance L1 decreases, so that the 5N
The inductance value of the Yuwa inductance Ll increases, and the lamp current of the discharge lamp 6 decreases.

The circuit portion from the astable multivibrator IC4 to the saturable inductance L described above is "
First dimming means 7A that does not change the oscillation frequency of the inverter section
This is an example of J.

To summarize the above, the first dimming unit 197A centered on the monostable multi-high break 103 controls dimming to reduce the lamp current by changing the resistance value of the variable resistor VR2 from small to large. ing.

Further, the second dimming means 7B with the astable multivibrator IC, which is set to medium +cx, controls dimming to reduce the lamp current by changing the resistance value of the variable resistor VR, to a small value. There is.

The variable resistors VR, , VR2 are interlocking volumes. First, the resistance value of the variable resistor VR2 changes continuously from small to large, and when the resistance value reaches the maximum, the resistance of the variable resistor VR, It is configured so that the value changes continuously from small to large.

These interlocking volumes VR1 and VR2 are an example of the dimming control unit RCJ referred to in the configuration of the invention.

Next, the operation will be explained based on FIG.

The first half of FIG. 4 shows the first dimming state based on adjusting the output control voltage to the saturable inductance Ll by the first dimming means 7A, and the second half shows the second dimming state. A second dimming state is shown based on adjusting the oscillation frequency of the inverter circuit In by means 7B.

■ Gradually increase the resistance value of variable resistor VR2 from zero to feel the pleasure of fully lighting the discharge lamp 6 (Figure !J4 (B)).
The off-duty of the output pulse of the output terminal 3 bins of the monostable multi-high brake IC gradually becomes shorter (FIG. 4 (J)).

■ When the off-duty of the output pulse at pin 3 decreases, the on-duty of the transistor T r 6 of the step-down chopper circuit channel decreases (FIG. 4 (K)).

Therefore, the voltage across the capacitor C9 of the step-down chopper circuit ch also gradually drops ((1, 1) in FIG. 4).

(2) As the voltage across the capacitor C9 drops, the inductance value of the saturable inductance L1 gradually increases (FIG. 4(M)), and the lamp current is decreased to dim the lamp.

■ The first stage of dimming by this first dimming means 7A is as follows:
This is continued until the resistance value of the variable resistor vR2 reaches its maximum value.

During this time, the second dimming means 7B does not operate. Therefore, the waveform of the portion related to the second dimming means 7B remains unchanged (FIG. 4(A) 1(C) to (H)).

■ When the resistance value of the variable resistor vR2 reaches its maximum value, the variable resistor VR is activated by the operation of the dimming control section RC.

The resistance value gradually increases from zero (Fig. 4 (A
)). As a result, the input voltage at the input terminal 5 bins of the astable multi-pipe lake 1C1 gradually drops (Fig. 4 (C)).

■ Along with this, the on-duty of the output voltage of the output terminal 3 of the astable multi-by-break IC gradually becomes shorter, and the oscillation frequency gradually increases (the 4th
Figure (D)).

Therefore, as for the Q output and Q output of flip-flop IC2 and the output voltages of AND circuits AND+ and AND2, the on-duty becomes gradually shorter and the frequency becomes higher (Fig. 4 (E) to (H)). ) ”)
.

■ Therefore, transistors Try and Tr4 are turned on.
The duty is gradually reduced and the switching frequency is gradually increased. As a result, the oscillation frequency of the inverter circuit In becomes higher, and the lamp current is reduced to perform dimming in the discharge lamp circuit.

(2) The second stage of dimming by the second dimming hand VJt7B is performed until the resistance value of the variable resistor VR reaches the human limit. During this time, the first dimming means 78 does not operate. Therefore, the waveform of the portion related to the first dimming means 7A remains unchanged (FIG. 4(B)).

([) ~ (M)).

〔Effect of the invention〕

According to this invention, there are the following effects.

(8) For dimming up to a certain level, use the first dimming means to dim the light without changing the oscillation frequency of the inverter, and for dimming at a deeper level, that is, at a lower level,
By controlling the frequencies it and II by the second dimming means, it is possible to prevent the discharge lamp from turning off or flickering during low-level dimming.

In particular, when adjusting a current limiting element such as a saturable inductance using the first dimming means, the voltage applied to the discharge lamp can always be kept constant, so that the IL extinguishment prevention at low level dimming can be The effect is large.

) The dimming means is divided into a first dimming means that does not change the oscillation frequency of the inverter section and a second dimming means that changes the oscillation frequency of the inverter section.
Since it is divided into two dimming means, compared to the conventional configuration where a single dimming means performs deep dimming,
It is possible to achieve miniaturization and cost reduction of the entire device.

(C) By performing dimming at a low level through frequency control by the second dimming means, malfunctions of television receivers and the like due to optical remote control interference can be alleviated.

Furthermore, the level of radiation noise generated from the discharge lamp can be reduced.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the basic configuration of this invention, Fig. 2 is a similar block diagram, Fig. 3 is a circuit diagram of a specific embodiment of this invention, and Fig. 4 is a diagram of each part. FIG. l... AC power supply, 2... voltage control section, 3... rectification smoothing section, 4... inverter section, 5... current limiting element, 6
... Discharge lamp, 7... Light control unit, 7A... First light control means, 7B... Second light control means, DB... Diode bridge, In... Inverter circuit , L...
・Saturable inductance, ch...step-down chopper circuit, RC...dimming I1) control section, VR,, VR2...variable resistor Figure 2 (A) Figure 3 procedural amendment (bladder 1985) October 30th

Claims (4)

[Claims] (1) A rectifying and smoothing section that converts AC power supply voltage into a DC voltage, an inverter section that converts the DC output voltage of this rectifying and smoothing section into a high-frequency voltage, a current limiting element that connects this inverter section to a discharge lamp, and an inverter Part oscillation frequency does not change type 1st
a second dimming means of an inverter section oscillation frequency changing type; for dimming up to a certain level, the first dimming means is operated; and for dimming to a deeper level, the first dimming means is operated; A discharge lamp dimming device comprising: a dimming control section that operates the second dimming means. (2) The discharge lamp dimming device according to claim (1), wherein the first dimming means that does not change the oscillation frequency of the inverter section is means for controlling the phase of an AC power source. (3) The discharge lamp dimming according to claim (1), wherein the first dimming means that does not change the oscillation frequency of the inverter section is a means for adjusting the DC output voltage of the rectifying and smoothing section using a chopper. Device. (4) The discharge lamp dimming device according to claim (1), wherein the first dimming means that does not change the oscillation frequency of the inverter section is a means for adjusting the impedance of a current limiting element.