JP2000030881A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of lighting two discharge lamps with one high-frequency power source even if the discharge lamps have a variation in characteristic. SOLUTION: A series circuit of an inductor L1 and a capacitor C1 is connected between the output ends of an inverter circuit. Windings of a balancer Ba are connected to two discharge lamps Laa, Lab in series respectively. Series circuits of the windings of the balancer Ba and the discharge lamps Laa, Lab are connected in parallel to form a parallel circuit, and a series circuit connected with this parallel circuit to a capacitor C2 in series is connected to a capacitor C1 in parallel. A resonance system of the inductor L1, capacitors C1, C2 and balancer Ba applies the starting voltage Vs to the discharge lamps Laa, Lab near the intersection of resonance characteristics at the time of no load and in lighting one lamp respectively.

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 for lighting two discharge lamps at a high frequency.

[0002]

2. Description of the Related Art In general, in a discharge lamp lighting apparatus of this type for lighting a discharge lamp at a high frequency, as shown in FIG. 3, a high frequency power supply Vh is connected to a discharge lamp La via an inductor L1, and the discharge lamp La is connected to the discharge lamp La. And a capacitor C1 connected in parallel. The inductor L1 limits the lamp current of the discharge lamp La, and the capacitor C1
1 and a resonance circuit, and the discharge lamp La is started by this resonance operation.

That is, in the circuit shown in FIG.
At the time of no load when a is not connected, the resonance circuit including the capacitor C1 and the inductor L1 has a resonance characteristic indicated by a solid line in FIG. Therefore, by setting the output frequency of the high-frequency power supply Vh to a relatively high preheating frequency fp, the voltage applied to the discharge lamp La is set to a low voltage (preheating voltage) at which the discharge lamp La does not start, and preheating is performed. After sufficient preheating, the output frequency of the high-frequency power supply Vh is reduced to a starting frequency fs higher than the preheating frequency fp, and the discharge lamp L
It has been considered that the discharge lamp La is started by increasing the voltage applied to a to the starting voltage Vs. When the discharge lamp La starts, the capacitor C1 and the inductor L1
And the discharge lamp La, a resonance circuit is formed, and the discharge lamp La
In the lighting state of, the lamp current characteristic indicated by the broken line in FIG. 4 is obtained. That is, after starting, the output frequency of the high-frequency power supply Vh is set to the lighting frequency fe so that the lamp current of the discharge lamp La becomes the rated value. In the basic circuit configuration described above,
In order to turn on the two discharge lamps, as shown in FIG. 5, capacitors C1a and C1b are respectively connected to the discharge lamps Laa and Lab.
Are connected in parallel, and a parallel circuit of each of the discharge lamps Laa, Lab and each of the capacitors C1a, C1b is connected in series to the winding of the balancer Ba, respectively, so that each of the discharge lamps Laa, Lab
A configuration has been proposed in which a series circuit of a capacitor and each of the capacitors C1a and C1b and each of the windings is connected in parallel to each other, and the parallel circuit is connected to a high-frequency power supply Vh via an inductor L1.
The balancer Ba is provided to suppress the imbalance of the lamp currents of the discharge lamps Laa and Lab.

The circuit shown in FIG. 5 is particularly effective when dimming the light output of the discharge lamps Laa and Lab by changing the output frequency of the high frequency power supply Vh. The unbalance of the lamp currents of the discharge lamps Laa and Lab, which tends to occur when the light output is reduced, can be suppressed by the balancer Ba.

As the high frequency power supply Vh, an inverter circuit 1 as shown in FIG. 6 is often used. The inverter circuit 1 shown in FIG. 6 uses a DC voltage output from an AC-DC conversion circuit 2 including a rectifier for rectifying an AC power supply AC such as a commercial power supply, a chopper circuit, and the like as a power supply.
It has a series circuit of a pair of switching elements Q1 and Q2 connected between the output terminals of the C conversion circuit 2. Further, a series circuit of an inductor L1-balancer Ba-discharge lamp Laa, Lab-capacitor C3 is connected in parallel to the switching element Q2 on the low side (negative side of the output of the AC-DC conversion circuit 2). Capacitor C3 is for DC cut,
It is set to a relatively large value. The switching elements Q1 and Q2 are controlled by the control circuit 3 to be turned on and off alternately, and generate a rectangular wave high-frequency voltage between both ends of the switching element Q2. This high frequency voltage is
Inductor L1-balancer Ba-discharge lamps Laa, Lab
By applying to the series circuit of the capacitor C3
High-frequency AC current can be passed through the discharge lamps Laa and Lab, and the discharge lamps Laa and Lab can be turned on at high frequency.

In this configuration, the frequency control is the same as in the case of a single lamp, and the preheating, starting, and lighting are sequentially performed by controlling the on / off frequency of the switching elements Q1 and Q2. Further, after lighting, a dimming signal is given from the dimming circuit 4 to the control circuit 3 in the form of a PWM signal, and the on / off frequency of the switching elements Q1 and Q2 is changed by the dimming signal to thereby discharge the lamps Laa and Lab. Can be adjusted.

However, in the circuit configurations shown in FIGS. 5 and 6, the current flowing through the balancer Ba is reduced by the discharge lamps Laa and La.
b and the capacitors C1a and C1b.
The current correction by the balancer Ba is performed not only for the variations in the lamp currents of the discharge lamps Laa and Lab, but also for the variations in the capacitors C1a and C1b. That is, even if the currents flowing through both windings of the balancer Ba are equal, there is a problem that the lamp currents are not equal due to the influence of the variation of the capacitors C1a and C1b.

Further, in the configurations shown in FIGS. 5 and 6, during full lighting (during rated lighting), the high-frequency power source Vh has a frequency close to the resonance frequency determined by the inductor L1, the capacitors C1a and C1b, and the capacitor C3. Since the (inverter circuit 1) is operated, when the output frequency of the high-frequency power supply Vh (inverter circuit 1) is increased and the light is dimmed, the output frequency departs from the resonance frequency and the discharge lamp L
The voltage applied to both ends of aa and Lab is greatly reduced. That is, it becomes difficult to maintain the lighting of the discharge lamps Laa and Lab with a low luminous flux.

As a technique for solving this problem, it has been proposed to intermittently lower the output frequency of the high-frequency power supply Vh when the light flux is low, thereby intermittently increasing the lamp voltage applied to the discharge lamps Laa and Lab. Have been. That is, during dimming, a high voltage is applied to both ends of the discharge lamps Laa and Lab in a pulsed manner. However, in order to realize this configuration, a high-frequency power supply V is applied so that a pulsed high voltage can be applied to both ends of the discharge lamps Laa and Lab.
h needs to be configured, causing a problem that the configuration of the high-frequency power supply Vh (control circuit 3) becomes complicated.

As a configuration for solving the former problem, a configuration shown in FIG. 7 can be considered. In other words, instead of connecting the resonance capacitors C1a and C1b in parallel with each of the discharge lamps Laa and Lab in the circuit configuration shown in FIG. 6, a series circuit of the inductor L1 and the resonance capacitor C1 is used. A parallel circuit is connected to the switching element Q2, and a series circuit of each winding of the balancer Ba and each of the discharge lamps Laa and Lab is connected in parallel. A series circuit of this parallel circuit and a capacitor C2 for resonance is connected to the capacitor C1. They are connected in parallel. In this configuration, the resonance capacitors C1, C
2 is also used for cutting the DC component to the discharge lamps Laa and Lab, so that the DC cut capacitor C3 becomes unnecessary, and the capacitors C1 and C2 are used for both the discharge lamps Laa and Lab.
Since the lamps are shared by the Labs, the balancer Ba is connected to both discharge lamps La.
Only the variation of the lamp currents a and Lab is corrected.

In the circuit configuration shown in FIG. 7, the discharge lamps Laa,
The resonance frequency f0 at the time of no load where Lab is not lit is determined by the inductor L1 and the capacitors C1 and C2. Then, as shown in FIG. 8, the discharge lamps Laa, La
If the lighting frequency fe at the time of full lighting of b (at the time of rated lighting) is lower than the resonance frequency f0, the lighting frequency fd at the time of dimming can be set to a range close to the resonance frequency f0. The voltage applied to the discharge lamps Laa and Lab can be made higher than that of the configuration shown in FIG. 6, so that it is not necessary to apply a pulsed high voltage to the discharge lamps Laa and Lab and the high-frequency power supply Vh ( Dimming becomes possible without using the control circuit 3). Note that the solid line in FIG. 8 indicates the resonance characteristics of the voltage applied to the discharge lamps Laa and Lab when there is no load, and the broken line indicates the frequency characteristics of the lamp current during lighting.

[0012]

When the two discharge lamps are to be turned on by one high-frequency power supply Vh as described above, one of the discharge lamps Laa and Laa may be affected by variations in the characteristics of the discharge lamps Laa and Lab. , Lab only, and the other does not. The cause will be described.

Now, as shown in FIG. 9A, two discharge lamps L
When neither aa nor Lab is lit, FIG.
As shown in (b), the voltage Vx applied to both discharge lamps Laa and Lab becomes equal. Since the applied voltage at this time operates with no load, it operates with the characteristics shown by the solid line in FIG. Thereafter, as shown in FIG. 10A, one discharge lamp Laa
Is turned on, the voltage Vy is applied to the discharge lamp Lab in an equivalent circuit as shown in FIG.

The impedance Z between the output terminals of the high-frequency power supply Vh in this state (see FIG. 11) can be expressed as follows. Now, let it be assumed that the impedance of the lit discharge lamp Laa is 0 to simplify the calculation. The output voltage of the high-frequency power supply Vh is a sine wave, the voltage value is E, and the inductance of the winding of the balancer Ba is T. Z = jG + jωL1, where Y = jG, 1 / Y = jωC1 + (1 / jF) jF = jωT + (1 / jωC2) In the above equation, Y represents the capacitors C1 and C in FIG.
2 and the impedance of the balancer Ba, and jF corresponds to the impedance of the capacitor C2 and the balancer Ba. Here, if X = jF, the applied voltage Vy to the unlit discharge lamp Lab is represented by the following equation. Vy = ｛(E / │Z│) × │Y│ / │X│｝ × ωT By the way, there are two frequencies at which the impedance Z obtained by the above equation becomes zero. That is, since the impedance Z becomes 0 at the two frequencies f1 and f2 as shown in FIG. 12, the frequency characteristic of the voltage applied to the unlit discharge lamp Lab has two characteristics as shown by the solid line in FIG. The resonance frequencies f1 and f2 exist. Here, the resonance frequencies f1 and f2 change according to the inductance of the winding of the balancer Ba, as indicated by the one-dot chain line in FIG.
The resonance frequency f increases as the inductance of the winding a increases.
1, f2 becomes low.

As a result, when only one of the two discharge lamps Laa and Lab is turned on, the configuration of the load circuit viewed from the high-frequency power supply Vh changes, and the resonance frequency also changes. Since it is greatly affected by the inductance of the winding, it is difficult to obtain a condition for lighting the unlit discharge lamp Lab. As a result, if one discharge lamp Laa is turned on first, the other discharge lamp Lab can be turned on. It may disappear.

The present invention has been made in view of the above circumstances, and an object of the present invention is to enable two discharge lamps to be operated by one high-frequency power supply even if the characteristics of the discharge lamps vary. To provide a discharge lamp lighting device.

[0017]

According to a first aspect of the present invention, there is provided a high-frequency power supply for outputting a high-frequency voltage, and a load circuit including two discharge lamps, the high-frequency voltage being applied through a resonance system. Discharge lamp lighting device having different resonance characteristics of the load circuit at the time of lighting and the resonance characteristics of the load circuit at the time of lighting one lamp,
The resonance system is configured so that a starting voltage is applied to the discharge lamp near the intersection of the resonance characteristics between when the load circuit is not loaded and when one lamp is turned on.

According to a second aspect of the present invention, there is provided a high-frequency power supply for outputting a high-frequency voltage and having a variable output frequency, and a load circuit including two discharge lamps and connected between output terminals of the high-frequency power supply. A circuit is a series circuit of an inductor and a first resonance capacitor connected between the output terminals of the high-frequency power supply, a balancer having windings connected in series to the discharge lamps, each winding of the balancer, and each discharge lamp. And a second resonance capacitor connected in series to a parallel circuit in which the series circuits are connected in parallel to each other, and a circuit comprising a discharge lamp, a balancer, and a second resonance capacitor is connected to the first resonance capacitor. A discharge lamp lighting device connected in parallel to a capacitor, the output frequency of a high-frequency power supply when a starting voltage is applied to the discharge lamp when there is no load, and the starting voltage is applied to the remaining discharge lamps when one discharge lamp is turned on. Apply Is substantially one resonance characteristics of the load circuit during matched to as no-load and the single-lamp during lighting is set the output frequency of the high-frequency power when.

According to a third aspect of the present invention, there is provided a high-frequency power supply for outputting a high-frequency voltage, and a load circuit including two discharge lamps and connected between output terminals of the high-frequency power supply, wherein the load circuit includes an output of the high-frequency power supply. A series circuit of an inductor and a first resonance capacitor connected between the ends, a balancer in which a winding is connected in series to each of the discharge lamps, and a series circuit of each winding of the balancer and each of the discharge lamps are connected in parallel. A second resonance capacitor connected in series to the connected parallel circuit, and a circuit composed of a discharge lamp, a balancer, and a second resonance capacitor is connected in parallel to the first resonance capacitor. A discharge lamp lighting device capable of dimming the light output of a discharge lamp by changing an output frequency of a high-frequency power supply at the time of lighting of an electric lamp, and an intersection of resonance characteristics between when a load circuit is not loaded and when a single lamp is lit. Start with a discharge lamp nearby In which an inductor and a first and second capacitor for resonance and the balancer is set so that the voltage is applied.

According to a fourth aspect of the present invention, in the second or third aspect of the invention, the first and second resonance capacitors are also used for cutting a DC component to the discharge lamp.

According to a fifth aspect of the present invention, there is provided a high-frequency power supply which outputs a high-frequency voltage and has a variable output frequency, and a load circuit including two discharge lamps to which the high-frequency voltage is applied through a resonance system. A discharge lamp lighting device having a resonance characteristic of a load circuit when a load is different from a resonance characteristic of a load circuit when a single lamp is turned on, wherein the high-frequency power source is set to an output frequency for applying a starting voltage to the discharge lamp when no load is applied. After that, when one lamp is turned on, the output frequency is switched to apply a starting voltage substantially equal to that of the discharge lamp.

According to a sixth aspect of the present invention, there is provided a high-frequency power supply for outputting a high-frequency voltage and having a variable output frequency, and a load circuit including two discharge lamps and connected between output terminals of the high-frequency power supply. A circuit is a series circuit of an inductor and a first resonance capacitor connected between the output terminals of the high-frequency power supply, a balancer having windings connected in series to the discharge lamps, each winding of the balancer, and each discharge lamp. And a second resonance capacitor connected in series to a parallel circuit in which the series circuits are connected in parallel to each other, and a circuit comprising a discharge lamp, a balancer, and a second resonance capacitor is connected to the first resonance capacitor. A discharge lamp lighting device connected in parallel to a capacitor, wherein the high-frequency power source sets an output frequency for applying a starting voltage to the discharge lamp when no load is applied, and then applies a starting voltage substantially equal to the discharge lamp when one lamp is turned on. It is intended to switch the output frequency.

According to a seventh aspect of the present invention, there is provided a high-frequency power supply for outputting a high-frequency voltage, and a load circuit including two discharge lamps and connected between output terminals of the high-frequency power supply, wherein the load circuit includes an output of the high-frequency power supply. A series circuit of an inductor and a first resonance capacitor connected between the ends, a balancer in which a winding is connected in series to each of the discharge lamps, and a series circuit of each winding of the balancer and each of the discharge lamps are connected in parallel. A second resonance capacitor connected in series to the connected parallel circuit, and a circuit composed of a discharge lamp, a balancer, and a second resonance capacitor is connected in parallel to the first resonance capacitor. A discharge lamp lighting device capable of dimming the light output of a discharge lamp by changing an output frequency of a high-frequency power supply at the time of lighting of an electric lamp, wherein the high-frequency power supply is an output that applies a starting voltage to the discharge lamp when there is no load. frequency After setting, in which switching to the output frequency for applying a substantially equal starting voltage to the discharge lamp at 1-lamp.

According to an eighth aspect of the present invention, in the sixth or seventh aspect, the first and second resonance capacitors are also used for cutting a DC component to the discharge lamp.

According to a ninth aspect of the present invention, in the invention of the fifth to eighth aspects, an output frequency for applying a starting voltage to the discharge lamp when the high-frequency power source is lit by one lamp, and a discharge lamp when the high-frequency power source is not loaded. Is set higher than the output frequency at which the starting voltage is applied.

[0026]

(Embodiment 1) As shown in FIG. 1 (a), the circuit configuration is the same as that of the discharge lamp lighting device shown in FIG. That is, an AC power supply that outputs a DC voltage using an AC power supply AC such as a commercial power supply as a power supply.
A DC conversion circuit 2 is provided, and a DC voltage output from the AC-DC conversion circuit 2 is converted into a high-frequency voltage by the inverter circuit 1. That is, the high frequency power supply Vh is configured using the inverter circuit 1. Inverter circuit 1 has A
The control circuit 3 includes a series circuit of a pair of switching elements Q1 and Q2 connected between the output terminals of the C-DC conversion circuit 2, and the switching elements Q1 and Q2 are alternately turned on and off at a high frequency by the control circuit 3. Accordingly, a rectangular high frequency voltage is generated between both ends of the switching element Q2.

A series circuit of an inductor L1 and a resonance capacitor C1 is connected between both ends of the switching element Q2, and a series circuit in which discharge lamps Laa and Lab are connected in series to respective windings of the balancer Ba. The series circuit of the circuit and the capacitor C2 for resonance is a capacitor C2.
1 in parallel. Capacitor C1 is inductor L1
Is set to a relatively small capacity so that the resonance frequency of the resonance circuit formed therewith is close to the on / off frequency of the switching elements Q1 and Q2.
The capacity is set to be relatively large so that a lamp current can flow through aa and Lab. In addition, balancer Ba
Is an AC-DC conversion circuit 2 for the discharge lamps Laa and Lab.
And the capacitor C2 is connected to the discharge lamp L
aa and Lab are connected to the positive side of the output of the AC-DC conversion circuit 2. A dimming signal is input to the control circuit 3 in the form of a PWM signal from an external dimming circuit 4, so that dimming control in a lighting state is enabled.

The feature of this embodiment is that the resonance characteristics when no load is applied (solid line) and the resonance characteristics when only one lamp is lit (dashed line) are set as shown in FIG. It is in the point which did. That is, when the starting voltages of the discharge lamps Laa and Lab are set to Vs, the inductances of the inductor L1, the capacitors C1 and C2, and the balancer Ba are set so that the two resonance characteristics intersect at the starting voltage Vs.

If such resonance characteristics are set, the operating frequency of the inverter circuit 1 is changed to the starting frequency fs while the two discharge lamps Laa and Lab are not lit after preheating.
When the discharge lamps Laa and Lab are lowered, if the discharge lamps Laa and Lab are normal, at least one of the discharge lamps Laa and Lab starts. Here, even if only one of the discharge lamps Laa and Lab is lit, the resonance characteristic is as shown by the dashed line in FIG. 1B, so that the starting voltage Vs is applied to the unlit discharge lamps Laa and Lab. The application can be continued, and as a result, both the discharge lamps Laa and Lab can be turned on.

The relationship between the resonance frequency f0 when no load is applied, the resonance frequency f1 when only one lamp is turned on, and the starting frequency fs is set to f0 <fs <f1. This is for the following reason. That is, when one lamp is turned on, if it is desired to obtain a sufficient starting voltage Vs at a frequency higher than the resonance frequency f1, it is necessary to increase the inductance of the balancer Ba, and the balancer Ba becomes bulky. Occurs. Conversely, if the starter is to be started near the resonance frequency f2, the balancer Ba can be reduced in size, but the maximum value of the resonance voltage is small, so that the balancer Ba is easily affected by variations in the balancer Ba, and the starter voltage Vs It becomes difficult to obtain. Therefore, f0 <fs <f
If the relationship is set to 1, the use of a relatively small balancer Ba makes it less likely to be affected by variations in the balancer Ba.

(Embodiment 2) In the present embodiment, as shown in FIG. 2A, the circuit has the same configuration as that of the first embodiment. However, as shown in FIG. 2B, the second embodiment differs from the first embodiment in that the starting frequency fs1 when no load is applied (solid line) is different from the starting frequency fs2 when one lamp is turned on. It is. For this reason, the starting control in the control circuit 3 is different from that in the first embodiment. That is, in the first embodiment, the starting voltage V can be changed without changing the operating frequency of the inverter circuit 1 between when there is no load and when one lamp is turned on.
However, in the present embodiment, attention is paid to the fact that the resonance characteristics change between no load and single lamp lighting, and if the operating frequency of the inverter circuit 1 is different between no load and single lamp lighting, It is making it.

Specifically, as shown in FIG. 2B, assuming that the starting voltages Vs of the two discharge lamps Laa and Lab are equal to each other, when there is no load, the resonance characteristics indicated by the solid line in FIG. The starting voltage Vs is given by operating the inverter circuit 1 at the starting frequency fs1, and after one lamp is turned on,
The inverter circuit 1 is operated at a starting frequency fs2 higher than the starting frequency fs1 so that the starting voltage Vs can be obtained with respect to the resonance characteristics indicated by the dashed line in FIG. Here, the control circuit 3 is configured to operate the inverter circuit 1 at the starting frequency fs1 and switch to the state of operating the inverter circuit 1 at the starting frequency fs2 after a certain period of time without particularly discriminating between no load and one lamp lighting. are doing.

If the configuration of this embodiment is adopted, it is not necessary to design so that the starting voltage Vs can be obtained at the intersection of the resonance characteristics between when there is no load and when one lamp is turned on, and the degree of freedom in design is increased. . That is, even when the starting voltage Vs cannot be obtained at the intersection of the resonance characteristics between when no load is applied and when one lamp is turned on, the two discharge lamps Laa and Lab can be reliably started. Moreover, the discharge lamps Laa, La at the intersection of the two resonance characteristics.
Since the voltage applied to b can be made lower than the starting voltage Vs, the inductance of the winding of the balancer Ba can be made smaller than in the first embodiment, and as a result, the size of the balancer Ba is reduced. . Other configurations and operations are the same as those of the first embodiment.

[0034]

According to a first aspect of the present invention, there is provided a high-frequency power supply for outputting a high-frequency voltage, and a load circuit including two discharge lamps and applying the high-frequency voltage through a resonance system. And a discharge lamp lighting device in which the resonance characteristics of the load circuit when the single lamp is lit are different from the resonance characteristics of the load lamp when the single lamp is lit. A resonance system is configured to be applied, and even if one of the two discharge lamps starts and the other does not start due to variations in the characteristics of the discharge lamp,
It becomes possible to apply a starting voltage to the other discharge lamp,
Both lights can be turned on.

According to a second aspect of the present invention, there is provided a high-frequency power supply that outputs a high-frequency voltage and has a variable output frequency, and a load circuit including two discharge lamps and connected between output terminals of the high-frequency power supply. A circuit is a series circuit of an inductor and a first resonance capacitor connected between the output terminals of the high-frequency power supply, a balancer having windings connected in series to the discharge lamps, each winding of the balancer, and each discharge lamp. And a second resonance capacitor connected in series to a parallel circuit in which the series circuits are connected in parallel to each other, and a circuit comprising a discharge lamp, a balancer, and a second resonance capacitor is connected to the first resonance capacitor. A discharge lamp lighting device connected in parallel to a capacitor, the output frequency of a high-frequency power supply when a starting voltage is applied to the discharge lamp when there is no load, and the starting voltage is applied to the remaining discharge lamps when one discharge lamp is turned on. Apply The resonance characteristics of the load circuit between the no-load state and the one-light-on state are set so that the output frequency of the high-frequency power supply substantially coincides with the output frequency of the high-frequency power supply. Even if one of them starts and the other does not start, the starting voltage can be applied to the other discharge lamp, and both can be turned on.

According to a third aspect of the present invention, there is provided a high-frequency power supply for outputting a high-frequency voltage, and a load circuit including two discharge lamps and connected between output terminals of the high-frequency power supply, wherein the load circuit includes an output of the high-frequency power supply. A series circuit of an inductor and a first resonance capacitor connected between the ends, a balancer in which a winding is connected in series to each of the discharge lamps, and a series circuit of each winding of the balancer and each of the discharge lamps are connected in parallel. A second resonance capacitor connected in series to the connected parallel circuit, and a circuit composed of a discharge lamp, a balancer, and a second resonance capacitor is connected in parallel to the first resonance capacitor. A discharge lamp lighting device capable of dimming the light output of a discharge lamp by changing an output frequency of a high-frequency power supply at the time of lighting of an electric lamp, and an intersection of resonance characteristics between when a load circuit is not loaded and when a single lamp is lit. Start with a discharge lamp nearby An inductor, first and second resonance capacitors, and a balancer are set so that a voltage is applied, and one of the two discharge lamps is started due to a variation in the characteristics of the discharge lamp. However, even when the other does not start, the starting voltage can be applied to the other discharge lamp, and both can be turned on.

According to a fourth aspect of the present invention, in the second or third aspect of the invention, the first and second resonance capacitors are also used for cutting a DC component to the discharge lamp. An increase in the number of components can be suppressed because the resonance capacitor is also used to cut the DC component to the discharge lamp.

According to a fifth aspect of the present invention, there is provided a high-frequency power supply that outputs a high-frequency voltage and has a variable output frequency, and a load circuit including two discharge lamps to which the high-frequency voltage is applied through a resonance system. A discharge lamp lighting device having a resonance characteristic of a load circuit when a load is different from a resonance characteristic of a load circuit when a single lamp is turned on, wherein the high-frequency power source is set to an output frequency for applying a starting voltage to the discharge lamp when no load is applied. After starting, one of the two discharge lamps is started and the other is not started due to variations in the characteristics of the discharge lamps, etc. However, the starting voltage can be applied to the other discharge lamp, and both can be turned on. In addition, since both discharge lamps are reliably started by changing the output frequency of the high-frequency power supply, circuit constants can be selected in a relatively wide range, and design is easy.

According to a sixth aspect of the present invention, there is provided a high-frequency power supply that outputs a high-frequency voltage and has a variable output frequency, and a load circuit including two discharge lamps and connected between output terminals of the high-frequency power supply. A circuit is a series circuit of an inductor and a first resonance capacitor connected between the output terminals of the high-frequency power supply, a balancer having windings connected in series to the discharge lamps, each winding of the balancer, and each discharge lamp. And a second resonance capacitor connected in series to a parallel circuit in which the series circuits are connected in parallel to each other, and a circuit comprising a discharge lamp, a balancer, and a second resonance capacitor is connected to the first resonance capacitor. A discharge lamp lighting device connected in parallel to a capacitor, wherein the high-frequency power source sets an output frequency for applying a starting voltage to the discharge lamp when no load is applied, and then applies a starting voltage substantially equal to the discharge lamp when one lamp is turned on. Switching to the output frequency, it is possible to apply a starting voltage to the other discharge lamp even if one of the two discharge lamps starts and the other does not start due to variations in the characteristics of the discharge lamp. It is possible to turn on both lights. In addition, since both discharge lamps are reliably started by changing the output frequency of the high-frequency power supply, circuit constants can be selected in a relatively wide range, and design is easy.

According to a seventh aspect of the present invention, there is provided a high-frequency power supply for outputting a high-frequency voltage, and a load circuit including two discharge lamps and connected between output terminals of the high-frequency power supply, wherein the load circuit includes an output of the high-frequency power supply. A series circuit of an inductor and a first resonance capacitor connected between the ends, a balancer in which a winding is connected in series to each of the discharge lamps, and a series circuit of each winding of the balancer and each of the discharge lamps are connected in parallel. A second resonance capacitor connected in series to the connected parallel circuit, and a circuit composed of a discharge lamp, a balancer, and a second resonance capacitor is connected in parallel to the first resonance capacitor. A discharge lamp lighting device capable of dimming the light output of a discharge lamp by changing an output frequency of a high-frequency power supply at the time of lighting of an electric lamp, wherein the high-frequency power supply is an output that applies a starting voltage to the discharge lamp when there is no load. frequency After setting, the output frequency is switched to an output frequency that applies a starting voltage substantially equal to the discharge lamp when one lamp is turned on. One of the two discharge lamps starts and the other does not start due to variations in the characteristics of the discharge lamp. Even in this case, the starting voltage can be applied to the other discharge lamp, and both lamps can be turned on. In addition, since both discharge lamps are reliably started by changing the output frequency of the high-frequency power supply, circuit constants can be selected in a relatively wide range, and design is easy.

According to an eighth aspect of the present invention, in the sixth or seventh aspect of the invention, the first and second resonance capacitors are also used for cutting a DC component to the discharge lamp. An increase in the number of components can be suppressed because the resonance capacitor is also used to cut the DC component to the discharge lamp.

According to a ninth aspect of the present invention, in the invention of the fifth to eighth aspects, the output frequency at which the starting voltage is applied to the discharge lamp when the high-frequency power source is lit is one, and the discharge lamp when the high-frequency power source is unloaded. The resonance frequency when one lamp is turned on is set higher than when no load is applied, and the inductance of the balancer can be set relatively low. As a result, the balancer can be downsized.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention, in which (a) is a circuit diagram,
(B) is an operation explanatory diagram.

FIG. 2 shows a second embodiment of the present invention, wherein (a) is a circuit diagram,
(B) is an operation explanatory diagram.

FIG. 3 is a schematic configuration diagram showing a conventional example.

FIG. 4 is an operation explanatory view of the above.

FIG. 5 is a circuit diagram showing a conventional example.

FIG. 6 is a circuit diagram showing a specific example of the above.

FIG. 7 is a circuit diagram showing another conventional example.

FIG. 8 is an operation explanatory view of the above.

FIG. 9 is an operation explanatory view of the above.

FIG. 10 is an operation explanatory view of the above.

FIG. 11 is an equivalent circuit diagram of a main part of the above.

FIG. 12 is an operation explanatory view of the above.

FIG. 13 is an explanatory diagram of the operation of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inverter circuit 2 AC-DC conversion circuit 3 Control circuit 4 Dimming circuit Ba Balancer C1 Capacitor C2 Capacitor L1 Inductor Laa, Lab Discharge lamp Q1, Q2 Switching element Vh High frequency power supply

Claims (9)

[Claims] A high-frequency power supply for outputting a high-frequency voltage;
And a load circuit including the discharge lamp of the lamp, wherein the high-frequency voltage is applied through a resonance system, wherein the resonance characteristics of the load circuit when no load is applied and the resonance characteristics of the load circuit when one lamp is turned on are different. A discharge lamp lighting device characterized in that a resonance system is configured such that a starting voltage is applied to the discharge lamp near an intersection of resonance characteristics between when no load is applied to the load circuit and when one lamp is turned on. 2. A high-frequency power supply that outputs a high-frequency voltage and has a variable output frequency, and a load circuit including two discharge lamps and connected between output terminals of the high-frequency power supply, wherein the load circuit includes a high-frequency power supply. A series circuit of an inductor and a first resonance capacitor connected between the output terminals of the balancer, a balancer having windings connected in series to the respective discharge lamps, and a series circuit of each winding of the balancer and each discharge lamp. And a second resonance capacitor connected in series to a parallel circuit connected in parallel with each other, and a circuit composed of a discharge lamp, a balancer, and a second resonance capacitor is connected in parallel to the first resonance capacitor. A discharge lamp lighting device, wherein an output frequency of a high-frequency power supply when applying a starting voltage to a discharge lamp when there is no load, and an output frequency when applying a starting voltage to the remaining discharge lamps when one discharge lamp is turned on. High frequency power supply A resonance characteristic of a load circuit between when no load is applied and when one lamp is lit so that the output frequency of the discharge lamp is substantially equal to the output frequency of the discharge lamp. 3. A high-frequency power supply for outputting a high-frequency voltage;
A load circuit including a discharge lamp of the lamp and connected between the output terminals of the high-frequency power supply, wherein the load circuit includes a series circuit of an inductor and a first resonance capacitor connected between the output terminals of the high-frequency power supply; A balancer in which windings are connected in series to the discharge lamps, and a second resonance capacitor connected in series to a parallel circuit in which series circuits of the balancer and the discharge lamps are connected in parallel; A circuit consisting of a discharge lamp, a balancer, and a second resonance capacitor is connected in parallel to the first resonance capacitor, and the output frequency of the high-frequency power supply is changed when the discharge lamp is turned on, thereby reducing the light output of the discharge lamp. A discharge lamp lighting device capable of dimming, wherein an inductor and first and second inductors are applied so that a starting voltage is applied to a discharge lamp near an intersection of resonance characteristics between when a load circuit is not loaded and when one lamp is turned on.
A discharge lamp lighting device, wherein a resonance capacitor and a balancer are set. 4. The discharge lamp lighting device according to claim 2, wherein the first and second resonance capacitors are also used for cutting a direct current component to the discharge lamp. 5. A load circuit having no load, comprising: a high-frequency power supply that outputs a high-frequency voltage and has a variable output frequency; and a load circuit that includes two discharge lamps and is applied with the high-frequency voltage through a resonance system. A discharge lamp lighting device having a resonance characteristic different from a resonance characteristic of a load circuit when a single lamp is turned on, wherein the high-frequency power source is set to an output frequency for applying a starting voltage to the discharge lamp when no load is applied. A discharge lamp lighting device characterized by switching to an output frequency for applying a starting voltage substantially equal to a discharge lamp at the time of lighting. 6. A high-frequency power supply that outputs a high-frequency voltage and has a variable output frequency, and a load circuit including two discharge lamps and connected between output terminals of the high-frequency power supply, wherein the load circuit includes a high-frequency power supply. A series circuit of an inductor and a first resonance capacitor connected between the output terminals of the balancer, a balancer having windings connected in series to the respective discharge lamps, and a series circuit of each winding of the balancer and each discharge lamp. And a second resonance capacitor connected in series to a parallel circuit connected in parallel with each other, and a circuit composed of a discharge lamp, a balancer, and a second resonance capacitor is connected in parallel to the first resonance capacitor. A discharge lamp lighting device, wherein the high-frequency power source is set to an output frequency for applying a starting voltage to the discharge lamp when no load is applied, and then switched to an output frequency for applying a starting voltage substantially equal to the discharge lamp when one lamp is turned on. A discharge lamp lighting device characterized by being replaced. 7. A high-frequency power supply for outputting a high-frequency voltage;
A load circuit including a discharge lamp of the lamp and connected between the output terminals of the high-frequency power supply, wherein the load circuit includes a series circuit of an inductor and a first resonance capacitor connected between the output terminals of the high-frequency power supply; A balancer in which windings are connected in series to the discharge lamps, and a second resonance capacitor connected in series to a parallel circuit in which series circuits of the balancer and the discharge lamps are connected in parallel; A circuit consisting of a discharge lamp, a balancer, and a second resonance capacitor is connected in parallel to the first resonance capacitor, and the output frequency of the high-frequency power supply is changed when the discharge lamp is turned on, thereby reducing the light output of the discharge lamp. A discharge lamp lighting device capable of dimming, wherein the high-frequency power source sets an output frequency for applying a starting voltage to the discharge lamp when no load is applied, and then applies a starting voltage substantially equal to the discharge lamp when one lamp is turned on. Out The discharge lamp lighting device, wherein the switching frequency. 8. The discharge lamp lighting device according to claim 6, wherein the first and second resonance capacitors are also used for cutting a DC component to the discharge lamp. 9. An output frequency for applying a starting voltage to the discharge lamp when the high-frequency power supply is lit by one lamp is set higher than an output frequency for applying a starting voltage to the discharge lamp when the high-frequency power supply is not loaded. The discharge lamp lighting device according to any one of claims 5 to 8, wherein: