JPH09251896A - Electric discharge lamp lighting device and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric discharge lamp lighting or illumination device capable of maintain its high input power-factor during full lighting, enabling deep light adjustment without causing low-frequency ripples (flickering) even during light adjustment, and satisfying high-frequency restrictions on the input current of the power supply. SOLUTION: In an electric discharge lamp lighting device of complex circuit system, when the pulse width or frequency of a switching pulse for driving a switching transistor Q11 of an inverter is controlled, the pulse width or frequency is so controlled as to be control light adjustment according to the degree of light adjustment during light adjustment, and the on duration or switching frequency of said switching transistor Q11 is so controlled as to control low distortion so that the instantaneous value of an alternating current power supply AC differs with its high or low duration. On the other hand, the low-frequency ripples to be generated during light output of a discharge lamp 24 is controlled to be reduced during light adjustment, and said low distortion control is controlled to be partially or entirely released in the half cycle of the alternating current power supply AC.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device and a lighting device which have a high input power factor and can reduce a low frequency ripple (flicker) of a light output during dimming.

[0002]

2. Description of the Related Art Conventionally, as a discharge lamp lighting device capable of dimming by mounting an inverter circuit and changing the ON time or switching frequency of its switching element,
JP-B-6-77480, JP-A-2-199796
Japanese Patent Laid-Open Publication No. 60-76899.

The proposal disclosed in Japanese Examined Patent Publication No. 6-77480 discloses that a discharge lamp lighting device uses a control signal that is applied when a discharge lamp is dimmed by changing the operating frequency of a separately excited high frequency conversion circuit. Therefore, the transient response of the lamp current at the time of dimming is always kept constant to prevent the occurrence of flicker at the time of dimming.

The proposal described in Japanese Patent Application Laid-Open No. 2-199796 controls the discharge lamp by keeping the switching frequency of the inverter circuit constant and changing the ON time of the switching element, and intermittently raises the light to a predetermined high level. A control circuit is provided that changes the on-time of the switching element so that a voltage is applied to the discharge lamp. Thus, it is possible to prevent the discharge lamp from extinguishing and flickering to a deep dimming level without changing the operating frequency of the inverter circuit, and to make it possible to stably dimming the discharge lamp.

The proposal described in Japanese Utility Model Laid-Open No. 60-76899 relates to a light control device for high-frequency lighting of a discharge lamp,
When the output of the high-frequency inverter is applied to the discharge lamp for high-frequency lighting, if the high-frequency oscillation frequency is kept constant, dimming is performed by changing the duty of the oscillation pulse, so that the ripple of the optical output of the discharge lamp does not occur. With
This is to widen the dimming range.

Furthermore, in addition to the above-described inverter circuit mounted, an inverter circuit and a chopper circuit as a direct current (smoothing) and power factor improving means are mounted in the preceding stage, and switching is performed between the inverter circuit and the chopper circuit. A discharge lamp lighting device that shares all or part of the elements and changes the on-time or switching frequency of the switching element to perform dimming (hereinafter, such a discharge lamp lighting device is a composite circuit type discharge lamp lighting device. Device)
Has been proposed. Examples of such a composite circuit type discharge lamp lighting device include a circuit shown in FIG. 9 described in JP-A-1-252175 and JP-A-64-3389.
There is a circuit as shown in FIG.

The circuit shown in FIG. 9 has a rectifier circuit 1 composed of a diode bridge for rectifying a commercial AC power supply AC, a series circuit of an inductor L1 and a diode D4, a smoothing capacitor 2, a switching transistor Q2.
, The collector of the transistor Q2 and the inductor L1
And a step-up type chopper circuit having a capacitor C3 connected to the connection point of the diode D4, a smoothing capacitor 2 and a switching transistor Q.
2, a resonance circuit composed of a capacitor C4 and an inductor L2, and an inverter circuit having a current limiting inductor L3.

The positive output terminal of the rectifier circuit 1 is an inductor L.
It is connected to one end of the smoothing capacitor 2 via a series circuit of 1 and the diode D4, and the negative side output end of the rectifier circuit 1 is connected to the other end of the smoothing capacitor 2. The capacitor C3 provided between the collector of the switching transistor Q2 and the connection point of the inductor L1 and the diode D4 is for applying the high frequency voltage generated at the collector of the transistor Q2 to the anode of the diode D4. A capacitor C5 connected between both terminals of the discharge lamp 5 is for preheating.

In the apparatus of FIG. 9, the commercial AC power source A
C is full-wave rectified by the rectifying circuit 1, and the rectified voltage is applied to the smoothing capacitor 2 via the series circuit of the inductor L1 and the diode D4. On the other hand, a switching pulse having a frequency of, for example, several tens of kHz is applied to the base of the switching transistor Q2 from a drive circuit (not shown). In this way, by turning on / off the switching transistor Q2, a high-frequency AC voltage is generated across the resonance circuit connected to the collector of the transistor, and this voltage is applied to the discharge lamp 5 via the current limiting inductor L3.
And the discharge lamp 5 is lit at high frequency. Prior to this lighting, the capacitor C5 preheats the discharge lamp 5.

In addition to the above operation, the high frequency voltage generated at the collector of the transistor Q2 is the capacitor C
It is applied to the connection point between the choke coil L1 and the diode D4, that is, the anode of the diode D4 via 3. As a result, the diode D4 is repeatedly turned on and off at a frequency higher than the frequency of the input AC power supply. Therefore, the AC input current has a conduction period even when the instantaneous value of the input AC voltage is low. That is, the input current will flow even outside the peak value of the AC voltage, and the input power factor can be increased.

By the way, dimming can be performed in such a circuit by controlling the ON period of the switching pulse supplied to the base of the transistor Q2 and narrowing it. Alternatively, dimming can be performed by controlling and increasing the frequency of the switching pulse supplied to the base of the transistor Q2.

In order to further reduce the distortion of the power input current, it is necessary to increase the smoothing voltage of the smoothing capacitor 2. However, if this is increased, it is necessary to use a high withstand voltage semiconductor or capacitor, which results in cost reduction. There was a problem that it would be disadvantageous.

Therefore, as a method for realizing low distortion even if the smoothing voltage is suppressed to a low level, the ON period (hereinafter referred to as ON width) of the switching element and the switching frequency can be controlled over a half cycle of the commercial power source. It is being appreciated. As an example of controlling the switching frequency of a switching element over a half cycle of a commercial power supply, Japanese Patent Laid-Open No. 3-19866.
There is one described in Japanese Patent No.

Next, an example of controlling the ON width of the switching element over the half cycle of the commercial power supply will be described with reference to FIG. 10 for the circuit of FIG.

As shown in FIGS. 10 (a) to 10 (d), with respect to the full-wave rectified voltage VREC output from the full-wave rectifier circuit 1 (see FIG. 10 (a)), the ON width of the switching pulse of the transistor Q2. Is controlled over a half cycle of the power supply as shown in FIG. 10 (b), the AC input current Iin will flow even outside the peak value of the AC voltage, and the input power factor can be increased. That is, the base of the transistor Q2 is designed such that the ON width is short at the peak of the power supply voltage and near the peak of the power supply voltage and is long near the valley so that the AC input current Iin flows even when the instantaneous value of the input AC voltage is low. The ON period of the switching pulse supplied to is controlled. By controlling in this way, the distortion rate of the power supply input current Iin can be reduced, the harmonic content rate can be reduced (hereinafter simply referred to as distortion reduction), and the input power factor can be improved. Figure 10 (b)
The dimming can be performed by controlling the ON period of the switching pulse supplied to the base of the transistor Q2 as shown in FIG. 10 (c) while keeping the low distortion control. Fig. 10 (c) shows the case when the dimming degree is shallow, Fig. 10 (d)
Is a waveform of a switching pulse when the dimming degree is further increased.

The circuit of FIG. 11 shows a discharge lamp lighting device of a composite circuit system in which a step-up chopper circuit and a modified half-bridge inverter are combined, and a full-wave through a noise filter circuit 13 is provided at both ends of the AC power supply AC. The input terminal of the rectifier circuit B is connected. The output terminal of the full-wave rectifier circuit B is connected to the input terminal of the booster type chopper circuit 12. In the chopper circuit 12, at the output end of the full-wave rectifier circuit B, via the collector and emitter of the transistor Q2,
Inductance L1 is connected. At both ends of the series circuit of the inductance L1 and the output terminal of the full-wave rectifier circuit B,
The smoothing capacitor C0 is connected through the diode D1. A half-bridge type inverter circuit 11 is connected to both ends of the capacitor C0. In the inverter circuit 11, a series circuit of a transistor Q1 and a transistor Q2 is connected to both ends of a capacitor C0.
Each of the transistors Q1 and Q2 has a diode D1
, D2 are connected in anti-parallel. The diodes D1 and D2 and the transistor Q2 in the chopper circuit 12 are also components of the inverter circuit 11. Transistor Q1
A discharge lamp la is connected to both ends of the capacitor via a coupling capacitor C3 and a current limiting inductance L2. A resonance capacitor C4 is connected to both ends of the discharge lamp la. Here, the inductance L in the inverter circuit 11
2 and the capacitor C4 are also components of the resonance circuit 14. One of the output terminals of the control circuit 15 is a transistor Q
One is between the base and emitter, and the other is the transistor Q2.
Are connected between the base and emitter of each.

In the circuit of FIG. 11, the control circuit 15 is
The ON signals are alternately supplied to the bases of the transistors Q1 and Q2, but the full-wave rectified voltage VRE output from the full-wave rectified circuit B as shown in FIGS.
When the on-width of the switching pulse of the transistor Q2 is controlled for C (see FIG. 10 (a)) over the half cycle of the power supply as shown in FIG. 10 (b), the AC input current Iin
Will flow even outside the peak value of the AC voltage,
The input power factor can be increased. That is, if the ON period of the switching pulse supplied to the base of the transistor Q2 is controlled so that the AC input current Iin flows even when the instantaneous value of the input AC voltage is low, the power input current Iin is reduced in distortion, The input power factor can be improved. With the low distortion control of Fig. 10 (b), Fig. 10 (c)
As shown in (3), dimming can be performed by controlling the ON period of the switching signal supplied to the base of the transistor Q2 to be narrowed. FIG. 10C shows the waveform of the switching pulse when the dimming degree is shallow, and FIG. 10D shows the switching pulse waveform when the dimming degree is further increased. A method of controlling the switching frequency instead of the method of controlling the ON width of the switching pulse (see Japanese Patent Laid-Open No. 3-198662).
It is also possible to reduce the distortion of the power input current.

12 (a) to 12 (d), the AC input current Iin, the rectified voltage VREC, and the rectified voltage VREC in FIG.
The respective waveforms of the smoothing voltage VDC across the smoothing capacitor and the lamp current IL of the discharge lamp are shown. 12 (d) shows the lamp current IL waveform at full light, and FIG. 12 (e) shows the lamp current I at dimming.
The L waveform is shown.

[0019]

By the way, when the low distortion control as described above is performed in the device of FIG. 9 or FIG. 11, the peak of the power supply voltage and the peak of the power supply voltage as shown in FIGS. The lamp current IL has a valley near that. This is not a problem at full light, but when dimming, the necking becomes large as shown in Fig. 12 (e), which causes disappearance and low-frequency ripple (flicker), which causes user discomfort. was there.

Therefore, the present invention is intended to solve such a problem, and it is possible to maintain a high input power factor at the time of all light and to generate a low frequency ripple (flicker) even when dimming. It is an object of the present invention to provide a discharge lamp lighting device and a lighting device capable of performing deep dimming without causing the occurrence and further satisfying the harmonic regulation of the input current of the commercial power supply. is there.

[0021]

According to the first aspect of the present invention,
A rectifier circuit for full-wave rectifying the output voltage of the AC power supply; a switching element for switching the output voltage of the rectifier circuit, and a smoothing capacitor for smoothing the switched voltage. A circuit means for reducing distortion, an inverter circuit which shares at least the switching element and converts the output voltage of the smoothing capacitor into a high frequency voltage, and a discharge lamp which is lit at a high frequency by the output voltage of the inverter circuit; A drive circuit for supplying a switching pulse to a switching element; and a composite circuit type discharge lamp lighting device for controlling a pulse width and / or a frequency of the switching pulse from the drive circuit. And / or frequency, depending on the dimming degree by the dimming signal during dimming First control means for controlling; for controlling the pulse width and / or frequency of the switching pulse from the drive circuit, and at least in the full light, the ON period and / or the switching frequency of the switching element, Second control means for controlling low distortion by making a period of a high instantaneous value different from a period of a low instantaneous value in a half cycle of the AC power supply; and a low frequency ripple generated in the optical output of the discharge lamp during dimming. In order to reduce the above, in a half cycle of the AC power supply, a third control means is provided for controlling so as to partially or completely cancel the low distortion control.

As the switching element, various switching semiconductor elements may be used in addition to the bipolar transistor and MOSFET. Further, the discharge lamp may be various discharge lamps in addition to the fluorescent lamp. Hereinafter, the same applies.

According to a second aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the first control means sets the pulse width of the switching pulse from the drive circuit to the ON period of the switching element. At the time of dimming, dimming control is performed so as to narrow according to the dimming degree; the second control means detects the full-wave rectified voltage from the rectifying circuit, and the ON period of the switching element is the moment of the AC power supply. The low distortion control is performed such that it is short in a period where the value is high and long in a period where the instantaneous value is low; the third control means detects a period during which the instantaneous value of the AC power source is high during dimming, and reduces the low value in the period. Distortion control is released, and the drive circuit only performs dimming control during the period.

According to a third aspect of the invention, in the discharge lamp lighting device according to the first aspect, the first control means controls the frequency of the switching pulse from the drive circuit,
The dimming control is performed so that the switching frequency of the switching element is increased according to the dimming degree during dimming; the second control means detects the full-wave rectified voltage from the rectifying circuit and switches the switching element. The low distortion control is performed such that the frequency is high in a period where the instantaneous value of the AC power source is high and is low in a period where the instantaneous value is low; the third control means controls the period when the instantaneous value of the AC power source is high during dimming. The low distortion control is detected and the low distortion control is released during the period, and the drive circuit only performs the dimming control during the period.

According to a fourth aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the first control means sets the pulse width of the switching pulse from the drive circuit to the ON period of the switching element. At the time of dimming, dimming control is performed so as to narrow according to the dimming degree; the second control means detects the full-wave rectified voltage from the rectifying circuit, and the ON period of the switching element is the moment of the AC power supply. The low distortion control is performed so that it is short in a period where the value is high and long in a period where the instantaneous value is low; the third control means releases the low distortion control at the time of dimming, and controls the drive circuit only to perform the dimming control. It is carried out;

According to a fifth aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the first control means controls the frequency of the switching pulse from the drive circuit,
The dimming control is performed so that the switching frequency of the switching element is increased according to the dimming degree during dimming; the second control means detects the full-wave rectified voltage from the rectifying circuit and switches the switching element. The low distortion control is performed so that the frequency is high during a period when the instantaneous value of the AC power source is high and is low during a period when the instantaneous value is low; the third control means releases the low distortion control during dimming, and drives the drive. The circuit is caused to perform only dimming control;

According to a sixth aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the first control means sets the pulse width of the switching pulse from the drive circuit to the ON period of the switching element. At the time of dimming, dimming control is performed so as to narrow according to the dimming degree; the second control means detects the full-wave rectified voltage from the rectifying circuit, and the ON period of the switching element is the moment of the AC power supply. The low distortion control is performed such that it is short in a period where the value is high and long in a period where the instantaneous value is low; the third control means detects whether or not a predetermined dimming degree is reached at the time of dimming, and a predetermined dimming control is performed. When the luminous intensity is reached, the low distortion control is released and the drive circuit is controlled only by the dimming control.

According to a seventh aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the first control means sets the frequency of the switching pulse from the drive circuit to:
The dimming control is performed so that the switching frequency of the switching element is increased according to the dimming degree during dimming; the second control means detects the full-wave rectified voltage from the rectifying circuit and switches the switching element. The low distortion control is performed so that the frequency is high during the period when the instantaneous value of the AC power source is high and is low during the period when the instantaneous value is low; the third control means determines whether a predetermined dimming degree is reached during dimming. Detect
When the predetermined dimming degree is reached, the low distortion control is canceled,
The drive circuit is caused to perform only dimming control;

According to an eighth aspect of the present invention, in the discharge lamp lighting device according to any one of the first to seventh aspects, the circuit means for reducing the distortion is connected in series with a positive side output terminal of the rectifier circuit. A series circuit of an inductor and a first diode connected to the second diode; and a second diode connected between a connection point of the series circuit of the inductor and the first diode and a collector of a switching transistor as the switching element; A smoothing capacitor connected between the cathode of the first diode and a negative output terminal of the rectifier circuit in a series circuit; and the inverter circuit has one end having a positive output of the smoothing capacitor. A resonance capacitor connected to the end; a collector connected to the other end of the resonance capacitor, and an emitter connected to the negative output terminal of the rectifier circuit. And a switching transistor whose base is connected to the drive circuit; and an inverter transformer in which a primary-side inductor is connected in parallel to the resonance capacitor and a secondary-side inductor is connected to both ends of the discharge lamp. Is characterized by.

The circuit means for reducing the distortion is composed of, for example, a step-up type chopper circuit, and the inverter circuit is
For example, it is a single circuit type separately excited transistor inverter and has a composite circuit configuration in which a switching transistor is shared by both circuits.

According to a ninth aspect of the present invention, a rectifier circuit for full-wave rectifying the output voltage of the AC power source; a first switching element for switching the output voltage of the rectifier circuit; and a smoothing capacitor for smoothing the switched voltage. Including and
Circuit means for reducing the distortion of the AC input current as well as rectifying the rectified voltage; including at least the first switching element, and first and second switching elements that alternately turn on and off; A composite comprising: an inverter circuit for converting an output voltage into a high frequency voltage; a discharge lamp that is turned on at a high frequency by the output voltage of the inverter circuit; and a drive circuit that supplies a switching pulse to the first and second switching elements. In a circuit type discharge lamp lighting device, which controls the pulse width and / or frequency of the switching pulse from the drive circuit, wherein the pulse width and / or frequency is set to a dimming degree by a dimming signal during dimming. First control means for controlling the pulse width of the switching pulse from the drive circuit and / or It has been made to control the frequency,
Second control means for controlling low distortion by making the ON period and / or the switching frequency of the switching element different at least during a period when the AC power supply has a high instantaneous value and a period when the AC power source has a low instantaneous value, at least during full light; Third control means for controlling the pulse width and / or the frequency of the switching pulse so as to eliminate the output fluctuation of the inverter circuit and reduce the low frequency ripple generated in the optical output of the discharge lamp during the dimming. It is characterized by having.

As the first and second switching elements, various switching semiconductor elements may be used in addition to bipolar transistors and MOSFETs. Also,
The discharge lamp may be various discharge lamps in addition to the fluorescent lamp.

According to a tenth aspect of the present invention, in the discharge lamp lighting device according to the ninth aspect, the first control means sets the pulse width of the switching pulse from the drive circuit to the ON period of the switching element. At the time of dimming, dimming control is performed so as to narrow according to the dimming degree; the second control means detects the full-wave rectified voltage from the rectifying circuit, and the ON period of the switching element is the moment of the AC power supply. The low distortion control is performed so that it is short in a high value period and long in a short instantaneous value period; the third control means detects a variation in the output voltage or the output voltage current of the inverter circuit during dimming, The pulse width of the switching pulse is controlled so as to eliminate the fluctuation.

According to an eleventh aspect of the present invention, in the discharge lamp lighting device according to the ninth aspect, the first control means adjusts the frequency of the switching pulse from the drive circuit with the switching frequency of the switching element. The dimming control is performed so as to increase according to the dimming degree when light is emitted; the second control means detects the full-wave rectified voltage from the rectifying circuit, and the switching frequency of the switching element is an instantaneous value of the AC power supply. Is controlled to be high during a high period and low during a low instantaneous value; the third control means detects a variation in the output voltage or output voltage current of the inverter circuit during dimming, and The frequency of the switching pulse is controlled so as to eliminate fluctuation.

The invention as defined in claim 12 is defined by claims 9 to 11.
In the discharge lamp lighting device according to any one of items 1 to 3, the inverter circuit is provided in series between output terminals of the rectifier circuit, and first and second switching transistors that are alternately turned on and off; 1, connected in parallel to each of the second switching transistor,
First and second diodes connected so as to be opposite to the current direction of each transistor; a relatively large-capacity first capacitor provided in parallel with the first switching transistor; An inverter transformer in which a primary-side inductor is connected between the first switching transistor and the first capacitor, and a secondary-side inductor is connected to both ends of the discharge lamp; and a capacity smaller than that of the first capacitor is set. A second capacitor forming a resonance circuit with the primary side inductor during an ON period of the second switching transistor.

The first capacitor may be an electrolytic capacitor or another capacitor as long as a sufficient capacity can be obtained.

A lighting device according to the thirteenth aspect of the present invention is
The discharge lamp lighting device according to any one of claims 1 to 12; and a lighting fixture main body that houses the discharge lamp lighting device;

According to the first aspect of the invention, in the discharge lamp lighting device using the high frequency inverter, the low distortion control that has been conventionally performed to reduce the distortion rate of the input current of the AC power source is released during dimming. In order to reduce the low frequency ripple generated in the light output of the electric lamp, the low distortion control is controlled so as to be partially or completely released over a half cycle of the AC power supply.

According to the second and third aspects of the invention, the low distortion control is canceled within the period width within the power supply half cycle (that is, the period when the instantaneous value of the AC power supply is high) according to the dimming degree by the dimming signal. With respect to the constriction (ripple) of the light output that increases as the degree of dimming increases, it is possible to control so as to enhance the effect of reducing the ripple. Alternatively, it is detected whether the dimming signal has reached a predetermined dimming degree, that is, whether the dimming ratio has reached a predetermined dimming ratio. Since the low distortion control is released within the period width (that is, the period when the instantaneous value of the AC power supply is high), the dimming degree becomes deeper than the specified value, and the constriction (ripple) of the optical output becomes anxious for the first time. It is possible to control so as to exert the effect of reducing the ripple.

In the inventions of claims 4 and 5, it is detected whether or not a dimming signal is inputted, and when the dimming time is detected, the low distortion control is released. Therefore, the optical output ripple appearing at the dimming time is released. Can be reduced.

According to the sixth and seventh aspects of the invention, it is detected whether or not the dimming signal has reached a predetermined dimming degree, that is, whether or not a predetermined dimming ratio has been reached, and the predetermined dimming ratio is detected. When the light ratio is reached, the low distortion control is released, so the dimming degree becomes deeper than a specified value during dimming and the light output is narrowed (ripple).
The ripple can be reduced only when it becomes anxious.

In the eighth aspect of the present invention, since the chopper circuit and the inverter circuit have a composite circuit configuration in which a switching transistor is shared, the chopper circuit improves the input power factor and dimming control, Low distortion control and optical ripple reduction control can be performed, and these controls can be realized with a circuit having a small number of components.

According to a ninth aspect of the present invention, an inverter circuit using the first and second switching elements that are alternately turned on and off is used, and the ON width of the switching pulse is adjusted so as to eliminate the output fluctuation of the inverter circuit. as well as/
Alternatively, it controls the frequency.

According to the tenth and eleventh aspects of the invention,
By detecting the output voltage or output current of the inverter circuit and controlling the ON width and / or frequency of the switching pulse, it is possible to eliminate the output fluctuation of the inverter circuit and reduce the optical ripple of the discharge lamp. Particularly, if the fluctuation of the lamp current is directly detected and controlled so as to eliminate the fluctuation, the low frequency ripple of the light output can be efficiently reduced.

According to the twelfth aspect of the invention, since the half bridge type inverter using two switching transistors is used in the inverter circuit, the load per switching transistor can be reduced.

According to the thirteenth aspect of the present invention, it is possible to realize an illuminating device which does not cause a low frequency ripple (flicker) in the light output even during dimming.

[0047]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a discharge lamp lighting device according to a first embodiment of the present invention.

The apparatus shown in FIG. 1 includes a rectifier circuit 21 composed of a diode bridge for rectifying a commercial AC power supply AC, a series circuit of an inductor L11 and a diode D11, a smoothing capacitor 22, and a switching transistor as a switching element. Q11 and a diode D12 connected between the collector of the transistor Q11 and the connection point of the inductor L11 and the diode D11,
A booster type chopper circuit as circuit means for reducing the distortion is provided, and the smoothing capacitor 22, the switching transistor Q11 as the switching element, a resonance circuit composed of the capacitor C11 and the inductor L11, and the transistor Q11. Diode D13 connected between collector and emitter, and primary and secondary inductor L
An inverter circuit having an inverter transformer 23 composed of 11 and L12 is provided. The switching transistor Q11 as a switching element is shared by the boost chopper circuit and the inverter circuit.

The positive output terminal of the rectifier circuit 21 is connected to one end of the smoothing capacitor 22 via a series circuit of an inductor L11 and a diode D11, and the negative output terminal of the rectifier circuit 21 is connected to the other end of the smoothing capacitor 22. ing. Both ends of the secondary inductor L12 of the transformer 23 are connected to the discharge lamp 24.
Are connected to both ends of the capacitor and are connected in parallel to the preheating capacitor C12 via the filaments at both ends thereof.

Further, the positive output terminal of the rectifier circuit 21 is connected to the input terminal of the gain controllable amplifier 25 via the resistor R11, and the output terminal of the amplifier 25 is connected to the control terminal of the ON width control circuit 26. There is. A gain control signal is supplied from the gain control circuit 29 to the gain control terminal of the amplifier 25. A gain control circuit 29 is supplied with a dimming signal from a dimming signal generator (not shown) (this signal has a different amplitude or pulse width depending on the dimming degree) through the interface circuit 28. A gain control signal having an amplitude corresponding to the dimming degree is output from 29.

On the other hand, the drive circuit 27 supplies a switching pulse to the base of the switching transistor Q11, and the ON width of the switching pulse is controlled by the ON width control circuit 26. . During dimming, the on-width control circuit 26 controls the on-width of the switching pulse of Q11 to increase or decrease at a constant rate according to the dimming degree for dimming control. The ON width of the switching pulse of Q11 is modulated in the time axis direction in order to improve the AC input current waveform so as to flow even outside the peak value (that is, to improve the power factor by reducing the distortion of the current waveform) (peak of the power supply voltage and It has a function of shortening the ON width in the vicinity and conversely increasing the ON width in the valley and its vicinity. In addition to this function, the light is passed through the amplifier 25 during dimming. A constant detection level is set for the rectified voltage VREC, and a period in which the waveform of the power supply half cycle of the voltage exceeds the predetermined level (that is, an amplitude level near the power supply peak detected in the power supply half cycle of the input rectified voltage). of The only have partial) has a function of controlling so that the switching pulse of a predetermined width stopped modulated low-distortion. As a result, at the time of dimming, the on-width modulation near the peak of the power supply can be relaxed to reduce the low frequency ripple of the optical output. Therefore, the ON-width control circuit 26 is supplied with the dimming signal from the dimming signal generating means (not shown) as the dimming control signal through the interface circuit 28, while the optical ripple reduction control signal during dimming is supplied from the amplifier 25. It is being supplied. The light ripple reduction control signal at the time of dimming is a rectified voltage waveform of a power supply cycle whose amplitude varies depending on the dimming degree at the time of dimming. The amplifier 25, the on-width control circuit 26, and the gain control circuit 29 configure a control unit 20 that performs dimming control, low distortion control, and optical ripple reduction control during dimming. The control means 20 is composed of a first control means for performing dimming control, a second control means for performing low distortion control, and a third control means for performing optical ripple reduction control during dimming. .

Next, the operation of the apparatus shown in FIG. 1 will be described. FIG.
In the above device, the commercial AC power supply AC is rectified by the rectification circuit 21 and applied to the smoothing capacitor 22 via the series circuit of the inductor L11 and the diode D11. On the other hand, the drive circuit 27 applies a switching pulse having a frequency of, for example, several tens of kHz to the base of the switching transistor Q11. In this way, by turning on / off the switching transistor Q11, a high frequency AC voltage is generated across the resonance circuit connected to the collector of the transistor Q11, and this voltage is applied to the inverter transformer 2
It is applied to the discharge lamp 24 via 3 and the discharge lamp 24 is lit at high frequency. Prior to this lighting, the capacitor C12 preheats the discharge lamp 24.

More specifically, when the switching transistor Q11 is turned on, current flows from the positive output terminal of the rectifier circuit 21 to the inductor L11, the diode D12, the collector / emitter of the transistor Q11, and the negative output terminal of the rectifier circuit 21, Energy is stored in the inductor L11. Next, when the transistor Q11 turns off, the energy stored in the inductor L11 is charged in the smoothing capacitor 22 through the diode D11. Then, when the transistor Q11 is turned on again, the smoothed voltage V0 of the smoothing capacitor 22 is applied to both ends of the capacitor C11 of the resonance circuit, and the capacitor C11 is charged to make the voltage across the capacitor V0. When the transistor Q11 turns off again, the capacitor C
The charge of 11 flows from one side of the capacitor C11 to the other side of the capacitor C11 through the inductor L11, the capacitor C11 is charged in the opposite polarity, and again flows from the capacitor C11 through the inductor L11 in the opposite direction and before discharging the capacitor C11. Charge to the polarity of. That is, when the transistor Q11 is turned off, the resonance operation is performed at the same time. Here, the transistor Q11 is turned on again, and the smoothed voltage V0 of the smoothing capacitor 22 is charged to both ends of the capacitor C11 of the resonance circuit. Of course, when the transistor Q11 is turned on, a current flows from the positive output terminal of the rectifier circuit 21 to the inductor L11, the diode D12, the collector / emitter of the transistor Q11, the negative output terminal of the rectifier circuit 21, and energy is stored in the inductor L11. . The diode D13 is inserted to prevent the voltage VC across the capacitor C11 from exceeding the smoothing voltage V0 due to the resonance voltage of the resonance circuit formed by the capacitor C11 and the inductor L11 while the transistor Q11 is on. There is.

2 (a), (b) and (c) are respectively the collector-emitter voltage VCE and collector current IC of the transistor Q11, the on / off period of the transistor Q11 and both ends of the capacitor C11 of the resonance circuit in FIG. The voltage VC is shown. In FIG. 2C, V0 is the smoothing voltage of the smoothing capacitor 22. The parabolic waveforms of VCE and VC in the off period of the transistor Q11 represent the resonance state.

Next, the ON width control of the transistor Q11, which is a feature of the present invention, will be described with reference to FIG.

In the device of FIG. 1, the rectified voltage VREC of the rectifier circuit 21 is a full-wave rectified voltage of a power supply half cycle period as shown in FIG. 3 (a). The voltage VREC is amplified by the gain controllable amplifier 25 and supplied to the ON width control circuit 26.

The amplifier 25 amplifies and outputs with a constant gain at the time of all light, and at the time of dimming, the gain control circuit 29.
A control signal corresponding to the degree of dimming is output from the light source, the gain is increased by this, and a rectified waveform voltage amplified according to the degree of dimming is output as compared with the case of full light (see FIG. 3 (b)). As described above, the on-width control circuit 26 performs the dimming control for narrowing the on-width of the switching transistor Q11 during dimming as compared with the full light based on the dimming signal from the interface circuit 28, while supplying the switching pulse to the power source. The distortion reduction control is performed by modulating in the time axis direction for half a cycle. In addition, the optical ripple at the time of dimming is controlled based on the control signal from the amplifier 25 (signal shown in FIG. 3 (b)). Control is performed to reduce the lamp current (that is, the lamp current during dimming has a flat current waveform without constriction). FIG.
The switching pulse waveform at full light is shown in (c). At the time of full light, only the distortion reduction control for modulating the switching pulse in the time axis direction is performed. It is controlled so that the pulse width is narrow near the peak of the power supply half cycle and wide near the peak of the instantaneous value of the power supply voltage. By this low distortion control, the input power factor at the time of all light is improved. Figure 3 (d)
Shows the switching pulse waveform of Q11 during shallow dimming. Figure 3 (e) shows the switching pulse waveform of Q11 during deep dimming. In the conventional dimming switching pulse waveform, as shown in FIGS. 10 (c) and 10 (d), the pulse width of the pulse waveform at full light is narrowed. As shown in d) and (e), at the time of dimming, at the same time as the low distortion control that narrows the pulse width of the pulse waveform at the time of full light, this low distortion control is stopped near the power supply peak. The on-width is controlled so as to have a uniform width in the vicinity of the power supply peak, which is equivalent to the on-width in the adjacent portion. During deep dimming, the peak period detected by the detection level near the power supply peak is wide, so the deeper the dimming level, the lower the distortion control in a wider range centered on the power supply peak, and the more uniform the on-width. As a result, the constriction of the lamp current that occurs during dimming is eliminated, and the low frequency ripple (flicker) of the light output can be reduced.

In the description of the operation of FIG. 3, the detection level near the power supply peak is set to a relatively low level that can detect even during shallow dimming, but the detection level can be detected only during deep dimming. May be In other words, when the dimming ratio is deepened during dimming, the detection level is set so that the vicinity of the power supply peak can be detected only when the predetermined dimming ratio is reached. The low distortion control can be released to eliminate the lamp current constriction.

Table 1 shows the effect of the apparatus example of FIG.

[Table 1] In Table 1, THD (abbreviation of Total Harmonic Distortion) is the total distortion factor of the input current, pf is the power factor, and pf = Win / (Vin ×
It is expressed as Iin). Iin is the input current, Win is the input power,
Vin is an input voltage (= commercial power supply voltage). IL is the lamp current, cf is the crest factor, and cf = Io-p
/ Irms. Io-p is the peak value of IL, Irms is IL
Is the effective value of.

In the conventional example shown in Table 1, as in the case of full light,
It also shows the percentage (%) with respect to the fundamental wave when the light ripple reduction control is not performed even during dimming. The standard (A) at the time of dimming is determined so as not to exceed (all-light fundamental wave Iin) × (IEC standard).

In the device of FIG. 1, even if the ripple reduction control of the light output was performed during dimming, the absolute value (A) of the input current satisfied the standard during dimming. Therefore, with the device of FIG. 1, there is no flicker even when dimming, and deep dimming is possible, and
We were able to obtain the results that satisfied the harmonic regulation of the input current.

In the embodiment of FIG. 1, the on-width control circuit 26 controls the on-width of the switching pulse supplied to the switching transistor Q11 to perform the dimming control and the low distortion control. . On the contrary,
As another embodiment of the present invention, an amplifier 2 that is provided with a switching frequency control circuit instead of the ON width control circuit 26 and is capable of gain control of the frequency of a switching pulse.
By controlling with the output voltage of 5, the dimming control and the low distortion control can be performed.

FIG. 4 is a block diagram showing a discharge lamp lighting device according to a second embodiment of the present invention.

ON width control circuit 2 in the apparatus shown in FIG.
In order to perform the optical ripple reduction control during dimming, 6 changes the amplification gain of the rectified voltage waveform according to the dimming degree, and keeps the detection level near the power source peak constant. In the device shown in FIG. 3, the gain of the amplifier 25A that amplifies the rectified voltage VREC is fixed, and the ON width control circuit 26A
Is for varying the detection level near the power supply peak according to the amplitude of the control signal from the interface circuit 28 that is output according to the dimming degree based on the dimming signal. That is, the ON width control circuit 26A is
Although the distortion reduction control (on-width modulation in the time axis direction) is performed as in FIG. 1, during dimming, the peak vicinity detection level is raised or lowered according to the dimming degree based on the dimming signal, and the dimming is shallow. When the dimming is deep, the detection level near the peak is lowered to a relatively wide period near the peak when the dimming is deep. On the other hand, the low distortion control is stopped. The amplifier 25A and the ON width control circuit 26A are
The control means 20 is configured to perform dimming control, low distortion control, and optical ripple reduction control during dimming. The control means 20 is
A first control unit for performing dimming control and a second control unit for performing low distortion control
Third control means for controlling light ripple reduction during dimming
And control means.

5 (a) to 5 (e), in the apparatus of FIG.
A characteristic operation waveform is shown. 3 (a) to 3 (e) except that the on-width control circuit 26A raises / lowers the detection level near the power source peak based on the dimming signal (see FIG. 5 (b)). That is, when the light control is shallow, as shown in FIG. 5 (b), the peak vicinity detection level is increased to stop the distortion reduction control only for a narrow period near the peak (FIG. 5 (d)).
When the dimming is deep, the detection level near the peak is lowered to stop the distortion reduction control for a relatively wide period near the peak as shown in FIG. )).

In the embodiment of FIG. 4, the on-width control circuit 26A controls the on-width of the switching pulse supplied to the switching transistor Q11 to perform the dimming control and the low distortion control. . On the other hand, as another embodiment of the present invention, the ON width control circuit 2
A switching frequency control circuit is provided instead of 6A, and the frequency of the switching pulse is controlled by the output voltage of the amplifier 25A and the dimming signal from the interface circuit 28, thereby performing dimming control and low distortion control. You can also

FIG. 6 is a block diagram showing a discharge lamp lighting device according to a third embodiment of the present invention.

In FIG. 6, both ends of the commercial AC power supply AC are connected to a pair of input ends of a rectifying circuit 31 composed of a diode bridge or the like, and between the output ends of the rectifying circuit 31,
The inverter circuit 30 is connected.

The inverter circuit 30 includes transistors Q21 and Q22 which are first and second switching elements and a first switching element.
And an electrolytic capacitor C21 serving as a second capacitor, a resonance capacitor C22, an inverter transformer 33 including a primary inductor L21 and a secondary inductor L22.
And diodes D21 and D22 connected in parallel to the transistors Q21 and Q22, respectively. Of the electrolytic capacitors C21 and C22, the electrolytic capacitor C21 connected in parallel with the transistor Q21 has a larger capacity. Transistors Q21 and Q22, which are the first and second switching elements, have a base connected to the transistor Q
A drive circuit 32 for alternately turning on and off 21 and Q22 is connected.

Both ends of the secondary inductor L22 of the inverter transformer 33 are connected to both ends of the preheating capacitor C23 through the filaments at both ends of the discharge lamp 34, respectively. The discharge lamp 34 serves as a load on the inverter circuit 30.

The inverter circuit 30 will be described in detail. The output terminal of the rectifier circuit 31 on the positive electrode side is a transistor Q21.
Collector-emitter and transistor Q22 collector-
It is connected to the negative output side of the rectifier circuit 31 through the series connection of the emitters, and is connected to the negative output side of the rectification circuit 31 through the series connection of the electrolytic capacitors C21 and C22.

The connection point between the transistors Q12 and Q22 is connected to the connection point between the electrolytic capacitor C21 and the capacitor C22 via the primary winding L21 of the inverter transistor 33. With such a connection, the electrolytic capacitor C21 and the capacitor C22 are connected in parallel to the transistors Q21 and Q22, respectively, and are connected in parallel to the diodes D21 and D22.

The drive circuit 32 creates a switching pulse and supplies it to the bases of the transistors Q21 and Q22,
The transistors Q21 and Q22 are alternately turned on and off. The ON width of the switching pulse output from the drive circuit 32 is controlled by a control signal from the ON width control circuit 40.

In addition to the inverter circuit 30 described above, in the present embodiment, each of the dimming control, the low distortion control, and the control for reducing the ripple of the light output during the dimming is performed by performing the ON width control of the switching pulse. Circuit means for controlling is provided.

The output terminal on the positive electrode side of the rectifier circuit 31 serves as an input voltage detection circuit 35 via a resistor R21. The input voltage detection circuit 35 detects the rectified voltage and supplies the detected voltage to one input terminal FULL of the switch circuit 39 via the buffer amplifier 36.

On the other hand, the collector of the transistor Q21, that is, the positive electrode side of the electrolytic capacitor C21 is connected to the voltage detection circuit 41. DC voltage is detected by the voltage detection circuit 41,
The detected voltage is supplied to the other input terminal DIM of the switch circuit 39 via the buffer amplifier 42. The output terminal COM of the switch circuit 39 is the ON width control circuit 4
Connected to 0. Two input terminals FU of switch circuit 39
Switching between LL and DIM is performed depending on whether a dimming signal from a dimming signal generating means (not shown) is input to the dimming control circuit 38 through the interface circuit 37. That is, when the dimming signal is not input, the switch circuit 39 is connected to the input terminal FULL side by the switching signal from the dimming control circuit 38, and when the dimming signal is input, the dimming control circuit 38 The switch circuit 39 is input to the DIM by the switching signal.
Side.

Further, at the time of dimming, the dimming control circuit 38 supplies the dimming control signal according to the dimming degree to the on-width control circuit 40 based on the dimming signal, whereby the on-width control circuit 40 is supplied. Reference numeral 40 controls the ON width of the switching pulse output from the drive circuit 32 so as to be narrowed according to the degree of dimming. The input voltage circuit 3
5, amplifier 36, dimming control circuit 38, switch circuit 3
9, the on-width control circuit 40, the voltage detection circuit 41, and the amplifier 42 constitute a control unit 50 that performs dimming control, low distortion control, and optical ripple reduction control during dimming. The control means 50 is composed of a first control means for performing dimming control, a second control means for performing low distortion control, and a third control means for performing optical ripple reduction control during dimming. .

Next, the operation of FIG. 6 will be described. A switching pulse is output from the drive circuit 32, whereby the transistors Q21 and Q22 are alternately turned on / off.
When the transistor Q21 is turned on, a current flows through the rectifier circuit 31 → transistor Q21 → inductor L21 → capacitor C22 → rectifier circuit 31, and when the transistor Q21 is turned off and the transistor Q22 is turned on, the energy stored in the inductor L21 causes the inductor L21 to flow. → Capacitor C22
→ A current flows through the diode D22. At this time, a resonance voltage is generated between the inductor L21 and the capacitor C22, and the action of this resonance voltage causes the input AC current (power factor correction current) to flow even during a period when the peak value of the voltage rectified by the rectifier circuit 31 is low. , Low distortion can be achieved. Next, with the transistor Q21 off and the transistor Q22 on, a current flows through the rectifier circuit 31 → electrolytic capacitor C21 → inductor L21 → transistor Q22 → rectifier circuit 31. Next, the transistor Q21 turns on and the transistor Q
When 22 is turned off, a current flows through inductor L21 → diode D21 → electrolytic capacitor C21 due to the energy stored in inductor L21. Then, with the transistor Q21 on and the transistor Q22 off, a current flows again in the rectifier circuit 31 → transistor Q21 → inductor L21 → capacitor C22 → rectifier circuit 31. The above operation is repeated. As a result, a high frequency voltage is induced in the secondary inductor L22 of the inverter transformer 33, and the discharge lamp 34 is lit at a high frequency.

Here, the ON width control of the switching pulse, which is a feature of this embodiment, will be described.

During full light, the full width rectified voltage waveform from the input voltage detection circuit 35 is supplied to the ON width control circuit 40 through the input terminal FULL of the switch circuit 39, and the ON width control circuit 40 is supplied. Is the input end of the switch circuit 39
The conventional low distortion control that controls the ON width in the time axis direction in response to the change in the amplitude level of the commercial power supply frequency from FULL (inversely proportional) is performed.

During dimming, the dimming signal enters the dimming control circuit 38 through the interface circuit 37, and the dimming control circuit 3
Reference numeral 8 supplies a dimming control signal to the ON width control circuit 40, while switching the switch circuit 39 to the input terminal DIM to input the DC voltage detection signal from the voltage detection circuit 41 to the ON width control circuit 40. During dimming, the ON width control circuit 40
On the other hand, the switching pulse width of the drive circuit 32 is controlled to be narrowed, while the voltage detection circuit 41 detects the fluctuation of the DC voltage and controls the ON width of the switching pulse so as to eliminate the fluctuation. Accordingly, during dimming, even if the lamp current of the discharge lamp 34 fluctuates (constricts), it is controlled so as to eliminate the fluctuation of the lamp current and flatten it, and it is possible to eliminate the ripple generated in the light output.

In the embodiment shown in FIG. 6, the ON width control circuit 40 controls the ON width of the switching pulse supplied to the switching transistors Q21 and Q22, thereby performing the dimming control and the low distortion control. there were. On the other hand, as another embodiment of the present invention, a switching frequency control circuit is provided in place of the ON width control circuit 40, and the frequency of the switching pulse is set to the output voltage of the amplifiers 36 and 42 and the output of the dimming control circuit 38. By controlling with a voltage, dimming control and low distortion control can be performed.

FIG. 7 is a block diagram showing a discharge lamp lighting device according to a fourth embodiment of the present invention.

In the apparatus of FIG. 6, the voltage detection circuit 41 detects the variation of the DC voltage at one end of the electrolytic capacitor C21 and controls the ON width so as to eliminate the variation. However, in the apparatus of FIG. Instead of this, the lamp current of the discharge lamp 43 is guided to the current detecting means by using the current coil 43 or the current transformer, the fluctuation of the lamp current is directly detected, and the ON width is controlled so as to eliminate the fluctuation. The input voltage circuit 35, the amplifier 36, the dimming control circuit 3
8, the switch circuit 39, the on-width control circuit 40, the current detection circuit 41A, and the amplifier 42 are dimming control, low distortion control,
Also, a control means 50 for performing light ripple reduction control during dimming is configured. Other configurations are the same as those in FIG. Therefore, the actions and effects are the same as in FIG.

In the embodiment of FIG. 7, the on-width control circuit 40 controls the on-width of the switching pulse supplied to the switching transistors Q21 and Q22, thereby performing the dimming control and the low distortion control. there were. On the other hand, as another embodiment of the present invention, a switching frequency control circuit is provided in place of the ON width control circuit 40, and the frequency of the switching pulse is set to the output voltage of the amplifiers 36 and 42 and the output of the dimming control circuit 38. By controlling with a voltage, dimming control and low distortion control can be performed.

FIG. 8 is a perspective view showing an illuminating device equipped with any one of the discharge lamp lighting devices shown in the embodiments of FIGS. 1, 4, 6 and 7.

In FIG. 8, a lighting device 101 has discharge lamps 105 and 106 attached to sockets 103 and 104 of a lighting fixture main body 102, respectively, and the discharge lamp lighting device 1 is internally provided.
07, and the discharge lamp lighting device 107
5, 106 are turned on. With such a structure, the embodiments of FIGS. 1, 4, 6, and 7 can be applied to the lighting device.

[0088]

According to the first aspect of the invention, in the discharge lamp lighting device using the high frequency inverter, the low distortion control for reducing the distortion rate of the input current of the AC power supply is performed at the time of dimming. Since the low distortion control is partially or wholly canceled over the half cycle of, the low frequency ripple (flicker) generated in the light output of the discharge lamp can be reduced during dimming.

According to the second and third aspects of the present invention, the low distortion control is canceled within the period width within the power supply half cycle according to the dimming degree by the dimming signal (that is, the period when the instantaneous value of the AC power supply is high). Therefore, it is possible to control the low-frequency ripple of the optical output, which increases as the degree of dimming increases, so as to enhance the effect of reducing the ripple. That is, the effect of reducing the optical ripple can be continuously enhanced according to the depth of the dimming degree. Alternatively, it is detected whether the dimming signal reaches a predetermined dimming level, and when it reaches the predetermined dimming level, the period width within the power supply half cycle (that is, the period when the instantaneous value of the AC power supply is high).
Since the low distortion control is canceled with, it is possible to perform control so as to exert the effect of reducing the ripple only when the dimming degree becomes deeper than a predetermined value and the low frequency ripple of the optical output becomes anxious. it can. As a result, the effect of improving the input power factor by the low distortion control can be maintained until the predetermined dimming degree is reached.

According to the inventions of claims 4 and 5, it is detected whether or not a dimming signal is input, and when the dimming time is detected, the low distortion control is released, so that the dimming control is performed at the full light dimming time. By distinguishing between time and time, it is possible to exert a certain reduction effect on the optical output ripple caused by the dimming during dimming.

According to the sixth and seventh aspects of the invention, it is detected whether or not the dimming signal has reached a predetermined dimming level, and when the dimming level is reached, the low distortion control is released. Only during dimming and when the dimming degree becomes deeper than a predetermined value and the low-frequency ripple of the light output becomes noticeable, it is possible to exert a certain reduction effect on the ripple.

According to the invention described in claim 8, since the chopper circuit and the inverter circuit have a composite circuit configuration in which a switching transistor is shared, the input power factor is improved by the chopper circuit and the dimming control is performed. The low distortion control and the optical ripple reduction control can be performed, and these controls can be realized with a circuit having a small number of components.

According to the ninth aspect of the invention, the inverter circuit using the first and second switching elements which are alternately turned on and off is used, and the on width and / or the frequency of the switching pulse are controlled to thereby make the inverter circuit. It is possible to eliminate the fluctuations in the output and reduce the light output ripple of the discharge lamp.

According to the tenth and eleventh aspects of the present invention, the output voltage or output current of the inverter circuit is detected to control the ON width and / or frequency of the switching pulse, thereby eliminating the output fluctuation of the inverter circuit. The light ripple of the discharge lamp can be reduced. Particularly, if the fluctuation of the lamp current is directly detected and controlled so as to eliminate the fluctuation, the low frequency ripple of the light output can be efficiently reduced.

According to the twelfth aspect of the invention, since the half-bridge type inverter using two switching transistors is used in the inverter circuit, the load per switching transistor can be reduced.

According to the thirteenth aspect of the present invention, it is possible to realize an illuminating device which does not cause a low frequency ripple (flicker) in the light output during dimming.

[Brief description of drawings]

FIG. 1 is a block diagram showing a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing voltage-current waveforms of respective parts in FIG.

FIG. 3 is a diagram for explaining light ripple reduction control during dimming in the apparatus of FIG.

FIG. 4 is a block diagram showing a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 5 is a diagram for explaining light ripple reduction control during dimming in the device of FIG.

FIG. 6 is a block diagram showing a discharge lamp lighting device according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing a discharge lamp lighting device according to a fourth embodiment of the present invention.

FIG. 8 is a perspective view showing a lighting device according to the present invention.

FIG. 9 is a block diagram showing a conventional discharge lamp lighting device.

FIG. 10 is a diagram for explaining control during dimming in the apparatus of FIG.

FIG. 11 is a block diagram showing another conventional discharge lamp lighting device.

FIG. 12 is a diagram for explaining a defect point which appears remarkably during conventional dimming.

[Explanation of symbols]

AC ... AC power supply 20 ... Control means (including first, second, and third control means) 21, 31 ... Rectifier circuit 22 ... Smoothing capacitor 23, 24 ... Inverter transformer Q11, Q21, Q22 ... Switching transistor (switching element ) 24, 34 ... Discharge lamp 27, 32 ... Drive circuit 26, 26A, 40 ... ON width control circuit 29 ... Gain control circuit 35 ... Input voltage detection circuit 38 ... Dimming control circuit 39 ... Switch circuit 41 ... Voltage detection circuit 41A ... current detection circuit 43 ... current coil 50 ... control means (including first, second, and third control means) 101 ... illumination device

Claims (13)

[Claims] 1. A rectification circuit for full-wave rectifying an output voltage of an AC power supply; a switching element for switching the output voltage of the rectification circuit; and a smoothing capacitor for smoothing the switched voltage, and converting the rectification voltage into a direct current. Together with circuit means for reducing the distortion of the AC input current; and an inverter circuit which shares at least the switching element and converts the output voltage of the smoothing capacitor into a high frequency voltage; and high frequency lighting by the output voltage of the inverter circuit A discharge lamp lighting device of a composite circuit system, comprising: a discharge lamp; and a drive circuit that supplies a switching pulse to the switching element, wherein the pulse width and / or frequency of the switching pulse from the drive circuit is controlled. Therefore, the pulse width and / or frequency depends on the dimming signal during dimming. First control means for controlling according to the dimming degree; for controlling the pulse width and / or frequency of the switching pulse from the drive circuit, and for at least full light, the ON period of the switching element and / or Or second control means for controlling low distortion by making the switching frequency different in a period having a high instantaneous value and a period having a low instantaneous value in a half cycle of the AC power supply; and a light output of the discharge lamp during dimming. To reduce the low frequency ripple that occurs in
A discharge lamp lighting device, comprising: a third control means for controlling so as to partially or completely cancel the low distortion control in a half cycle of the AC power supply. 2. The first control means performs dimming control of a pulse width of the switching pulse from the drive circuit so that an ON period of the switching element is narrowed according to dimming degree during dimming; The second control means detects a full-wave rectified voltage from the rectifier circuit, and the ON period of the switching element is low so as to be short during a period when the instantaneous value of the AC power source is high and long during a period where the instantaneous value is low. Distortion control;
During dimming, the third control means detects a period during which the instantaneous value of the AC power source is high, cancels low distortion control during that period, and causes the drive circuit to perform only dimming control during that period. The discharge lamp lighting device according to claim 1. 3. The first control means controls the frequency of the switching pulse from the drive circuit so that the switching frequency of the switching element becomes higher according to the dimming degree during dimming; The second control means detects a full-wave rectified voltage from the rectifier circuit, and has a low distortion so that the switching frequency of the switching element is high during a period when the instantaneous value of the AC power source is high and is low during a period when the instantaneous value is low. Control; the third control means, during dimming,
2. The discharge according to claim 1, wherein a period in which the instantaneous value of the AC power supply is high is detected, the low distortion control is released in the period, and the drive circuit is only subjected to dimming control in the period. Electric lighting device. 4. The first control means performs dimming control of the pulse width of the switching pulse from the drive circuit so that the ON period of the switching element becomes narrower according to the dimming degree during dimming; The second control means detects a full-wave rectified voltage from the rectifier circuit, and the ON period of the switching element is low so as to be short during a period when the instantaneous value of the AC power source is high and long during a period where the instantaneous value is low. Distortion control;
2. The discharge lamp lighting device according to claim 1, wherein the third control unit releases the low distortion control during dimming and causes the drive circuit to perform only dimming control. 5. The first control means performs dimming control of the frequency of the switching pulse from the drive circuit so that the switching frequency of the switching element becomes higher according to the dimming degree during dimming; The second control means detects a full-wave rectified voltage from the rectifier circuit, and has a low distortion so that the switching frequency of the switching element is high during a period when the instantaneous value of the AC power source is high and is low during a period when the instantaneous value is low. 2. The discharge lamp lighting device according to claim 1, wherein the third control means releases the low distortion control during dimming and causes the drive circuit to perform only dimming control. 6. The dimming control of the pulse width of the switching pulse from the drive circuit such that the ON period of the switching element is narrowed according to dimming degree during dimming. The second control means detects a full-wave rectified voltage from the rectifier circuit, and the ON period of the switching element is low so as to be short during a period when the instantaneous value of the AC power source is high and long during a period where the instantaneous value is low. Distortion control;
The third control means detects at the time of dimming whether or not a predetermined dimming degree is reached, and when the predetermined dimming degree is reached, the low distortion control is released and the drive circuit is dimming controlled. The discharge lamp lighting device according to claim 1, wherein: 7. The first control means performs dimming control of the frequency of the switching pulse from the drive circuit so that the switching frequency of the switching element is increased according to the dimming degree during dimming. The second control means detects a full-wave rectified voltage from the rectifier circuit, and has a low distortion so that the switching frequency of the switching element is high during a period when the instantaneous value of the AC power source is high and is low during a period when the instantaneous value is low. The third control means detects whether or not a predetermined dimming degree is reached during dimming, and when the predetermined dimming degree is reached, the low distortion control is released and the drive circuit is controlled. The discharge lamp lighting device according to claim 1, wherein only the dimming control is performed. 8. The circuit means for reducing the distortion includes a series circuit of an inductor and a first diode connected in series to a positive output terminal of the rectifier circuit; and a series circuit of the inductor and the first diode. A second diode connected between the connection point and the collector of the switching transistor serving as the switching element; connected between the cathode of the first diode in the series circuit and the negative output terminal of the rectifier circuit Smoothing capacitor;
And a resonance capacitor having one end connected to the positive output terminal of the smoothing capacitor; a collector connected to the other end of the resonance capacitor, and an emitter connected to the negative electrode of the rectifier circuit. A switching transistor connected to a side output terminal and a base connected to the drive circuit; and an inverter transformer having a primary side inductor connected in parallel to the resonance capacitor and a secondary side inductor connected to both ends of the discharge lamp. The discharge lamp lighting device according to any one of claims 1 to 7, further comprising: 9. A rectifier circuit for full-wave rectifying the output voltage of an AC power supply; a first rectifier circuit for switching the output voltage of the rectifier circuit.
Switching device and a smoothing capacitor for smoothing the switched voltage, and circuit means for reducing the distortion of the AC input current together with the DC conversion of the rectified voltage; at least the first switching element is shared and alternated. An inverter circuit that includes first and second switching elements that are turned on and off, and that converts the output voltage of the smoothing capacitor into a high frequency voltage; a discharge lamp that is turned on at a high frequency by the output voltage of the inverter circuit; A drive circuit for supplying a switching pulse to the second switching element;
In a discharge lamp lighting device of a composite circuit system comprising: a pulse width and / or frequency of the switching pulse from the drive circuit, wherein the pulse width and / or frequency is a dimming signal during dimming. Controlling the pulse width and / or the frequency of the switching pulse from the drive circuit, the first control means controlling the switching element according to the dimming degree by Second, low distortion control is performed by making the switching frequency different between a period in which the instantaneous value of the AC power source is high and a period in which the instantaneous value is low.
A control means for controlling the pulse width and / or frequency of the switching pulse so as to eliminate the output fluctuation of the inverter circuit and reduce the low frequency ripple generated in the optical output of the discharge lamp during the dimming. A discharge lamp lighting device comprising: a control means; 10. The first control means performs dimming control so that a pulse width of the switching pulse from the drive circuit is narrowed in accordance with a dimming degree during an on period of the switching element; The second control means detects a full-wave rectified voltage from the rectifier circuit, and the ON period of the switching element is low so as to be short during a period when the instantaneous value of the AC power source is high and long during a period where the instantaneous value is low. Distortion control; the third control means detects a variation in the output voltage or the output voltage current of the inverter circuit during dimming, and controls the pulse width of the switching pulse so as to eliminate the variation. The discharge lamp lighting device according to claim 9. 11. The first control means controls the frequency of the switching pulse from the drive circuit so that the switching frequency of the switching element becomes higher according to the dimming degree during dimming; The second control means detects a full-wave rectified voltage from the rectifier circuit, and has a low distortion so that the switching frequency of the switching element is high during a period when the instantaneous value of the AC power source is high and is low during a period when the instantaneous value is low. The third control means detects a variation in the output voltage or the output voltage current of the inverter circuit during dimming and controls the frequency of the switching pulse so as to eliminate the variation. The discharge lamp lighting device according to claim 9. 12. The inverter circuit includes first and second switching transistors which are provided in series between output terminals of the rectifier circuit and which are alternately turned on and off; and the first and second switching transistors, respectively. A first diode and a second diode connected in parallel to the first switching transistor and in a direction opposite to the current direction of each transistor; A large-capacity first capacitor; an inverter transformer in which a primary-side inductor is connected between the first switching transistor and the first capacitor, and a secondary-side inductor is connected to both ends of the discharge lamp; The capacitance is set to be smaller than that of the first capacitor, and the primary side inductor and the resonance circuit are connected during the ON period of the second switching transistor. A second capacitor to be formed;
The discharge lamp lighting device according to any one of 1. 13. A lighting device comprising: the discharge lamp lighting device according to any one of claims 1 to 12; and a lighting fixture main body that houses the discharge lamp lighting device.