JPH0118559B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge lamp lighting device, and more particularly to a discharge lamp lighting device used by being connected to a dimmer.

2. Description of the Related Art Conventionally, a discharge lamp lighting device that dims and lights a discharge lamp by inputting phase-controlled power is known, for example, as shown in FIG. 1. This kind of device 1
is equipped with a rectifier 2 and an inverter lighting circuit 3, controls the ignition phase angle φ _A of each half cycle by a dimmer 5 connected to a commercial power source 4, and inputs this output voltage to control the discharge lamp 6. For example, a fluorescent lamp is dimmed and turned on.

However, according to this type of device 1, dimming lighting of the discharge lamp 6 is performed by controlling the ignition phase angle (conduction angle) by the dimmer 5, and adjusting the ignition phase angle φ _A and π radian in each half cycle. Widen the conduction period between
Although the light intensity of the discharge lamp 6 is changed narrowly, the upper limit of the dimming lighting range is regulated by the discharge starting voltage of the discharge lamp 6, so the secondary voltage is set to a certain constant value. However, the disadvantage was that it became extremely narrow.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has a wide dimming range and less flickering of the discharge lamp during deep dimming.
The purpose is to provide a discharge lamp lighting device.

In order to achieve this object, the present invention provides a discharge lamp lighting device that dims and lights a discharge lamp with a voltage that controls the ignition phase angle of each half cycle of an AC power source.
means for detecting a change in the ignition phase angle for each half cycle; means for determining an extinguishing phase angle in accordance with the change in the ignition phase angle; and when the ignition phase angle exceeds a predetermined value. A phase control circuit having means for reducing the amount of change in the phase angle difference between the extinguishing phase angle and the ignition phase angle is provided.

Embodiments of the invention will be described below with reference to the accompanying drawings.

FIG. 2 is a block diagram showing the configuration of a discharge lamp lighting device according to the present invention, and this discharge lamp lighting device 11 includes a rectifier 12, an inverter lighting circuit 1
3, and an internal phase control circuit 14 provided between the rectifier 12 and the inverter lighting circuit 13, the power whose phase is controlled by the dimmer 5 is inputted through two power supply wirings, and the discharge lamp 6, e.g. Dim and turn on the light lamp.

Here, the dimmer 5 is a device that continuously changes the brightness of the discharge lamp 6 by controlling the ignition phase angle φ _A of each half cycle in the voltage waveform of the commercial power supply 4 connected to its input side. As is widely known in the past, it is composed of a thyristor or the like. The control range of the ignition phase angle φ _A is, for example, from zero to 0.5π for each half cycle, from the relationship with the discharge starting voltage of the discharge lamp 6.
It is set to around radians.

Also, of the discharge lamp lighting device 11, the rectifier 12
Various discharge lamp lighting circuits including an inverter lighting circuit 13 have been proposed in the past, in which the alternating current output of the dimmer 5 is full-wave rectified by a rectifier 12, and this rectified voltage is made up of transistors, thyristor inverters, etc. The inverter lighting circuit 13 converts the voltage into a high frequency voltage (for example, several KHz or more) and lights the discharge lamp 6. A phase control circuit 14 is connected between the rectifier 12 and the inverter lighting circuit 13 via input terminals a, c and output terminals b, d.

FIG. 3 is an explanatory diagram of this phase control circuit 14, in which FIG. A is a block diagram and FIG. B is a circuit diagram.
Furthermore, FIG. 4 is a waveform diagram of each part of this phase control circuit. This phase control circuit 14 includes the rectifier 12
The second half of the same half cycle is cut at an extinguishing phase angle φ _B corresponding to the ignition phase angle _{φ A of} each half cycle of the output waveform of For example, when the value approaches 0.5π radian, the amount of change in the phase angle φ ₀ between the extinction phase angle φ _B and the firing phase angle φ _A is reduced, and the change in the firing phase angle φ _A is means for detecting the extinction phase angle φ _B in accordance with changes in _the firing phase angle φ _A ; and means for fixing φ _B.

That is, the rectifier 1 as shown in FIG. 4A, B, and A
When the output voltage V _io of 2 is input to input terminal a,
This input voltage _Vio is applied to the level determination circuit 21.

The level judgment circuit 21 detects a change in the ignition phase angle φ _A , and is composed of resistors R ₁ , R ₁ ′ and a transistor T _r1 , and detects a change in the ignition phase angle φ A when the input voltage V _io becomes below the judgment level, i.e. t ₀ shown in Figure 4 A and B
Outputs a rectangular output from time to time t ₁ .
The rising time t ₀ of this output is constant, but the falling time t ₁ becomes correspondingly longer as the ignition phase angle φ _A increases, and is determined by a predetermined maximum value of the ignition phase angle φ _A , e.g. Time t ₂ around 0.5π radians
The falling point becomes longer until (B, B in Fig. 4).
The output of this level judgment circuit 21 is the output of the clear circuit 2.
2 and the integrating circuit 23.

The clear circuit 22 is composed of a capacitor C ₂ , a resistor R ₂ and a transistor T _r2 , and outputs a clear signal at the rising time t ₀ of the output of the level determination circuit 21 (FIG. 4 A, B, C), and outputs a clear signal to the integrator circuit 23. Add to. Integrating circuit 23 consists of resistor _R3 and capacitor
_C3 integrates the output of the level judgment circuit 21, and when the clear signal is applied to the integration circuit 23, the integrated output is cleared and then the output of the level judgment circuit 21 is integrated again. That is, as shown in FIGS. 4A and 4D, this integration circuit 23 starts integration after being cleared by a clear signal, continues integration until time _t1 when the output of the level determination circuit 21 falls, and then It holds the integral value, is cleared by the next clear signal, and starts integrating again. The output voltage of this integrating circuit 23 is determined by the length of the output voltage of the level determining circuit 21 (from the rising time t ₀ to the falling time
t ₁ ) becomes longer, that is, the firing phase angle φ _A becomes larger, the larger the firing phase angle φ A becomes correspondingly larger. The output of this integrating circuit 23 is applied to a clamp circuit 24.

When the ignition phase angle φ _A exceeds a predetermined value, the clamp circuit 24 adjusts the ignition phase angle φ _B to be described later.
is fixed, and consists of a Zener diode ZD ₄ , and when the output voltage of the integrating circuit 23 exceeds a certain value (clamp level), the integrated _output is Clamp (Figure 4B, d). Therefore, the ignition phase angle φ _A increases to a predetermined maximum control range, for example, around 0.5π radians for each half cycle, and correspondingly, the length of the output voltage of the level determination circuit 21 increases as described above. Even if the falling time is longer from _t1 to _t2 , the output voltage of the integrator 23 increases until it is clamped by the clamp circuit 24, but it does not increase beyond the clamp level, so the maximum integrated output The rising point t ₂ ' will be fixed. The output of this clamp circuit 24 is applied to a timer circuit 25.

The timer circuit determines the extinguishing phase angle φ _B according to the change in the ignition phase angle φ _A , and includes a programmable unidirectional transistor.
PUT and resistor R ₅ and its anode side (A side)
resistor R _5A and capacitor C _5A on the gate side (G
Resistor R _5G and Zener diode ZD ₅ are connected to each side), the resistor R _5A and capacitor C _5A on the anode side form an integrating circuit, the resistor R _5G and Zener diode ZD ₅ on the gate side form a constant voltage source, Configure each. This timer circuit 25
is the timer output (extinguishing phase angle φ _B control signal) at phase angle time t ₁₁ according to the ignition phase angle φ _A of the input voltage V _io
(Figure 4 A, E). That is, the anode-side resistor R _5A and capacitor C _5A in this timer circuit 25 are for integrating the output of the level determination circuit 21, and after the integrated output is cleared by the clear signal, the level determination circuit 21 It rises rapidly until the falling point _t1 , and then continues to rise slowly, and when the next clear signal is input, it is cleared and integration starts again (timer anode voltage waveforms in Figures 4A and 2). On the other hand, this timer circuit 25
The resistor R _5G on the gate side and the Zener diode ZD ₅ constitute a constant voltage source, and apply a constant voltage E to the gate side (timer gate voltage waveforms in Figures 4A and 4). When the anode side voltage increases beyond E, the programmable unification occurs at the time _t11 when it exceeds E.
Transistor PUT conducts and outputs a timer output (extinguishing phase angle φ _B control signal). At the time point _t11 when the timer output is generated, as the ignition phase angle φ _A increases, the output voltage of the integrating circuit 23 increases correspondingly, and as this integral increases, the anode side voltage of the timer circuit 25 also increases. As the ignition phase angle φ _A becomes larger, the time point t ₁₁ at which this timer output occurs also becomes longer.
However, when the output voltage of the integrating circuit 23 exceeds the clamp level, it is clamped by the clamp circuit 24, so this timer circuit 25
The anode side voltage of is also constant, and the time point at which the timer output is generated is also fixed at time _t12 , as shown in FIG. 4B and E, and does not become longer than that. The output of this timer circuit 25 is applied to a control output circuit 26.

The control output circuit 26 consists of a thyristor SCR ₆ , and when the output of the timer circuit 25 is input to the gate of the thyristor SCR ₆ , it becomes closed.
Apply the output voltage to control switch 37. This control switch 27 consists of a transistor T _r7 , and the output of the control output circuit 26 is applied in the opposite direction between the collector and base of this transistor T _r7 .
Input terminal c and output terminal d of this control switch 27
Switch between the closed state and the open state. Therefore, the output terminal b connected to the level determination circuit 21 through the diode 28 has an output voltage of a so-called double-cut waveform in which the latter half of each half cycle of the input voltage V _io is cut off at the extinction phase angle φ _B. V _put appears. The extinction phase angle φB of this output voltage V _put is
Since it is controlled by the timer _output , as shown in _FIG . _B ) also decreases from π radians to 0.5π radians (Fig. 4 A, E, F), but when the firing phase angle φ _A exceeds a preset maximum value, for example, when φ _A0 becomes around 0.5π radians, , the timer output generation timing is also fixed at time _t12 as shown in Figure 4 B and E, so the extinction phase angle φ _B is also fixed at φ _B0 , and this extinction phase angle φ _B0 and the firing phase The difference φ ₀ from the angle φ _A0 also becomes a constant value (FIG. 4B, f). Therefore, even if the ignition phase angle φ _A0 within the maximum setting range slightly fluctuates back and forth due to sudden fluctuations in the input voltage V _io , the extinguishing phase angle φ _B does not change. Note that when the ignition phase angle φ _A of the input voltage V _io is zero (at full light), the control switch 27 remains closed, so the
At the output terminal b, _{an output voltage Vput having} the same waveform as the input voltage Vio appears.

Next, the operation of the above embodiment will be explained.

At full light (φ=0) when the phase of the commercial power supply 4 is not controlled by the dimmer 5, the AC voltage of the commercial power supply 4 is fully rectified by the rectifier 12, and this output is sent to the phase control circuit 14. Figure 6 through
A substantially unchanged waveform is inputted to the inverter lighting circuit 13 as shown in _A1 , and the discharge lamp 6 is lit with a lamp current having a waveform as shown in FIG _{. 6A2} .

On the other hand, at the time of dimming in which the ignition phase angle φ _A is controlled by the dimmer 5, in the intermediate region where the ignition phase angle φ _A is from zero to around 0.5π radian (during intermediate dimming), When the ignition phase angle φ _A is increased from zero in the direction of 0.5π radian using the dimmer 5 , this output is full-wave rectified by the rectifier 12 and applied to the phase control circuit 14 . In this phase control circuit 14, as the ignition phase angle φ _A increases, the output of the timer circuit 25 advances from π radian to 0.5π radian and becomes the phase, so that the ignition phase angle φ _A of each half cycle is adjusted accordingly. At extinction phase angle φ _B , the second half of the same half cycle is cut, as shown in Fig. 6 B ₁
It outputs a voltage with a so-called double-sided waveform as shown in . This output voltage is applied to the inverter lighting circuit 13, and a lamp current as shown in FIG. _6B2 flows through the discharge lamp 6, and the discharge lamp 6 is dimmed and lit by this current.

Furthermore, when the ignition phase angle φ _A increases with the dimmer 5 and moves to the maximum value of the variable range, for example, around 0.5π radians (during deep dimming), the extinction phase angle φ _B also increases accordingly. It moves from to around 0.5π radian. During this deep dimming, commercial power supply 4
If the ignition phase angle φ A changes rapidly due to waveform distortion, etc., the ignition phase angle φ _A and extinction phase angle φ _B will also change accordingly. However, when the ignition phase angle φ _A is around 0.5π radian, Since the arc phase angle φ _B is also around 0.5π radian, the _ignition phase angle _{φ A and} the extinction phase Fluctuations in the light output (flickering of the discharge lamp 6) due to fluctuations in the angle φ _B become relatively large. Therefore _, in order to reduce the flickering of the discharge lamp 6, when the ignition phase angle φ _A is greater than a certain value, the extinguishing phase angle φ _B
It is sufficient if the fluctuation of is made slow or the extinction phase angle φ _B is fixed. Therefore, in this embodiment, by fixing the extinction phase angle φ _B ,
It's resolved. That is, when the ignition phase angle φ _A moves to around 0.5π radian, the integral output of the integrating circuit 23 is clamped by the clamp circuit 24 and the output of the timer circuit 25 is fixed, so that the extinguishing phase angle φ _B also changes. The phase angle difference φ ₀ between the extinction phase angle φ _B and the ignition phase angle φ _A becomes a predetermined constant value as shown in _Fig . Input the output to the inverter lighting circuit,
With the lamp current having a waveform as shown in Figure _6C2 ,
The discharge lamp 6 is turned on with minimal light intensity. Therefore, while using the conventional dimmer 5, the conduction angle can be changed over a wide range including the peak value of the power supply voltage, and not only the dimming range is significantly widened, but also the power supply fluctuation during deep dimming can be changed. The accompanying flickering of the discharge lamp 6 is reduced.

FIG. 7 is a circuit diagram of another embodiment of the phase control circuit 14. This phase control circuit 14 includes a means for detecting a change in the lighting phase angle φ _A , a means for forming an extinguishing phase angle φ _B in accordance with a change in the ignition phase angle φ _A , and a means for detecting a change in the ignition phase angle φ _A. The phase control circuit 14 includes means for slowing or following the movement of the extinction phase angle φ _B when the phase angle φ B exceeds a predetermined value. The only difference is the clamp circuit 24, and the other circuit configurations are the same as those in the previous embodiment.

That is, this clamp circuit 24' adjusts the extinction phase angle φ _B when the ignition phase angle φ _A exceeds a predetermined value.
slows down or follows the movement of
A series-connected Zener diode ZD _{4 ′} and a resistor R ₄ are added in parallel to the Zener diode ZD ₄ of the clamp circuit 24 according to the embodiment, and both ends of the Zener diode ZD ₄ ′ and the capacitor C _5A of the timer circuit 25 are connected in parallel. A transistor T _r4 is provided between the two through resistors R ₄ ′ and R ₄ ″.

In the phase control circuit 14 according to this embodiment, as in the previous embodiment, when the ignition phase angle φ _A increases from zero toward the maximum control range, for example, 0.5π radians, the ignition is extinguished accordingly. The phase angle φ _B also advances from π radian to 0.5π radian, but when the ignition phase angle φ _A approaches 0.5π radian, the resistor R connected in series with the Zener diode ZD ₄ ' As the voltage of transistor T _r4 increases, transistor T _r4 becomes closed, and a portion of the charging current flowing to capacitor C _5A of timer circuit 25 flows to resistors R ₄ ′ and R ₄ ″ connected to the emitter and collector of transistor T _r4. Therefore, the amount of charge in the capacitor _C5A decreases.As shown in Fig. 8, the slope angle (rate of rise) of the latter half of the timer anode voltage curve decreases due to the variable resistance function of the transistor _Tr4 .
becomes smaller, and the time required to cross the timer gate straight line determined by the Zener diode ZD ₄ and the Zener diode ZD ₅ of the timer circuit 25 becomes longer. That is, the intersection point of the timer anode voltage curve and the timer gate straight line moves backward. Therefore, the amount of decrease in the extinction phase angle φ _B becomes small.

In addition, the degree of rise in the first half of the timer anode curve in Figure 8 is similar to that of a Zener diode.
Depends on ZD ₄ . Therefore, in this example,
As shown in FIG. 9A, with respect to the fluctuation of the ignition phase angle φ _A during deep dimming, the fluctuation of the extinguishing phase angle φ _B can be made slower, thereby reducing the flickering of the discharge lamp 6. In addition, in this embodiment, by appropriately selecting the values of the resistors R ₄ ′ and R ₄ ″ in the clamp circuit 24 ′, the ignition phase angle during deep dimming can be adjusted as shown in FIG. 9B. The extinguishing phase angle φ _B is made to follow the fluctuation of φ _A , that is, the extinguishing phase angle φ _B is also delayed with respect to the delay of the ignition phase angle φ _A , thereby reducing flickering of the discharge lamp 6. You can also do that.

Since the device according to the present invention is configured as described above, during dimming, the second half of each half cycle of the phase-controlled input waveform is cut at the extinction phase angle corresponding to the firing phase angle of each half cycle. , the light intensity of the discharge lamp is adjusted by widening or narrowing the conduction period between the ignition phase angle and the extinguishing phase angle, so the phase angle is 0.5π.
The light intensity of the discharge lamp can be reduced to an extremely small amount around radians, so the peak value of the power supply voltage can be used while using a conventional dimmer, and the dimming range is significantly widened. Moreover, when the ignition phase angle exceeds a predetermined value, for example, when it approaches 0.5π radian, the amount of change in the phase angle difference between the extinguishing phase angle and the ignition phase angle becomes small, so that deep adjustment is possible. This has the effect of reducing the flicker of the discharge lamp due to distortion of the power supply waveform, etc. during the light period.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional two-wire power supply discharge lamp lighting device, Fig. 2 is a block diagram showing the configuration of the discharge lamp lighting device according to the present invention, and Fig. 3 is a diagram showing the discharge lamp lighting device of Fig. 2. FIG. 4 is an explanatory diagram of the phase control circuit in the device, where FIG. A is a block diagram, FIG. B is a circuit diagram, and FIG.
The figure is a waveform diagram of each part of the phase control circuit of Figure 3, Figure 5 is a dimming characteristic diagram showing the relationship between the ignition phase angle and the extinction phase angle in the phase control circuit of Figure 3, and Figure 6 is a diagram of the dimming characteristics. FIG. 2 is an input/output waveform diagram of the inverter lighting circuit in the block diagram, FIG. 7 is a circuit diagram of the phase control circuit in a discharge lamp lighting device according to another embodiment, and FIG.
The figure is a waveform diagram of the integrating circuit, clamp circuit, and timer circuit in Figure 7, and Figure 9 A and B are waveform diagrams of the
It is an output diagram at the time of deep dimming in the circuit diagram of the figure. 1, 11... Discharge lamp lighting device, 2, 12... Rectifier, 3, 13... Inverter lighting circuit, 6...
Discharge lamp, 14... Phase control circuit, 21... Level determination circuit, 24, 24'... Clamp circuit, 25
...Timer circuit.

Claims (1)

[Scope of Claims] 1. In a discharge lamp lighting device that dims and lights a discharge lamp with a voltage that controls the ignition phase angle of each half cycle of an AC power supply, a change in the ignition phase angle of each half cycle is detected. means for determining an extinguishing phase angle according to a change in the ignition phase angle, and a phase between the extinguishing phase angle and the ignition phase angle when the ignition phase angle exceeds a predetermined value. A discharge lamp lighting device comprising a phase control circuit having means for reducing the amount of change in angular difference. 2. In the device according to claim 1,
The phase control circuit includes means for detecting a change in the ignition phase angle, means for determining an extinguishing phase angle in accordance with the change in the ignition phase angle, and a means for detecting a change in the ignition phase angle. A discharge lamp lighting device comprising means for fixing an extinguishing phase angle. 3. In the device according to claim 1,
The phase control circuit includes means for detecting a change in the ignition phase angle, means for determining an extinguishing phase angle in accordance with the change in the ignition phase angle, and a means for detecting a change in the ignition phase angle. A discharge lamp lighting device comprising means for slowing or following the movement of the extinguishing phase angle.