JP4239356B2 - Discharge lamp lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a discharge lamp lighting device for lighting a high pressure discharge lamp such as a high pressure sodium lamp or a metal halide lamp.
[0002]
[Prior art]
Currently, high-pressure discharge lamps such as high-pressure sodium lamps and metal halide lamps are widely used in store lighting, road lighting, factory lighting, stadium lighting, and the like. As a discharge lamp lighting device for lighting this type of high-pressure discharge lamp, a configuration as shown in FIG. 7 is mainly employed.
[0003]
In the circuit shown in FIG. 7, a series circuit of a choke coil L11 as a ballast and an autotransformer T11 for generating a high voltage is inserted between an AC power supply AC such as a commercial power supply and a lamp La that is a high-pressure discharge lamp. It is. A capacitor C11 is connected between the two terminals TM1 and TM2 to which the AC power supply AC is connected, and a series circuit of two capacitors C12 and C13 is connected in parallel to the series circuit of the choke coil L11 and the capacitor C11. The A trigger element Q11 is inserted between the connection point of the capacitors C12 and C13 and the intermediate tap of the autotransformer T11. That is, a ballast circuit 10 including a capacitor C11 and a choke coil L11, and an igniter 11 including capacitors C12 and C13, an autotransformer T11, and a trigger element Q11 are provided.
[0004]
In this configuration, when the AC power supply AC is turned on, a current flows to the primary side of the autotransformer T11 (winding between one end on the choke coil L11 side and the intermediate tap) due to the breakover of the trigger element Q11, and the autotransformer T11. A high voltage is generated between both ends. That is, the high voltage is applied to the lamp La in a form in which the high voltage at both ends of the autotransformer T11 is superimposed on the voltage of the AC power supply AC, and the lamp La is started.
[0005]
By the way, in tunnel lighting or the like, a high pressure discharge lamp may be dimmed to save power at night. In view of this, a circuit configuration shown in FIG. 8 is considered in order to dimm the high pressure discharge lamp. In this configuration, the dimming choke L12 is inserted between the choke coil L11 of the ballast circuit 10 and the autotransformer T11 of the igniter 11, and when dimming is unnecessary, both ends of the dimming choke L12 are short-circuited. Therefore, a relay contact RY1 as a switch element is connected in parallel to the dimming choke L11. However, if the relay contact RY1 is turned on during the daytime, the dimming choke L12 does not function, and thus operates in the same way as the circuit configuration shown in FIG. 7, while at night the lamp contact RY1 is turned off when the relay contact RY1 is turned off. In addition to the choke coil L11, the dimming choke coil L12 is inserted in the power supply path to La, and the lamp current is limited. As a result, the light output of the lamp La is fully turned on (only the choke coil L11 is turned on). It can be reduced more than the inserted lighting state, generally rated lighting state).
[0006]
By the way, when the relay contact RY1 is changed from the on-state to the off-state so as to suddenly change from the fully lit state to the dimming state, a state in which the applied voltage of the lamp La becomes higher than the fully lit state may occur for a moment. is there. In particular, it is known that such a phenomenon is likely to occur when the ratio of the light output in the dimming state to the light output in the fully lit state is increased. As described above, when the lamp voltage suddenly becomes higher than the full lighting state, the lamp current may suddenly decrease to cause the lamp to disappear.
[0007]
Therefore, in order to suppress the extinction at the transition from the fully lit state to the dimming state, the secondary voltage of the lighting device 1 (that is, the dimming choke coil L12, the autotransformer T11, and the lamp La is applied to the series circuit). It is considered to set a high voltage in advance. As this type of configuration, as shown in FIG. 9, a configuration using a leakage transformer T10 instead of the choke coil L11 is considered. In the leakage transformer T10 used in FIG. 9, if the primary side voltage is 200V, the secondary side voltage is boosted to 240V. The winding inductance and the leakage inductance are used to connect the lamp La to the lamp La. It has a function to limit current.
[0008]
[Problems to be solved by the invention]
However, when the voltage is increased using the leakage transformer T10 in the ballast circuit 10 as in the configuration shown in FIG. 9, there arises a problem that the copper loss and the iron loss increase and the circuit loss increases. In addition, since the leakage transformer T10 is larger than the normal choke coil L11 and is heavier and more expensive, the configuration employing the leakage transformer T10 is not necessarily desirable as a means for solving the problem of extinction. .
[0009]
The present invention has been made in view of the above reasons, and its purpose is to be dimmable, to prevent the lamp from extinguishing when shifting to the dimming state, and to be smaller than the case of using a leakage transformer. Another object is to provide a discharge lamp lighting device that is inexpensive.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a rectifier circuit for rectifying an AC power source, a first converter for converting the output voltage of the rectifier circuit and changing the output voltage, and an output of the first converter as a power source to a discharge lamp. And a control circuit for controlling the output voltage of the first converter and the power supplied from the second converter to the discharge lamp. In the control circuit, the light of the discharge lamp Supplying from the second converter to the discharge lamp so that the light output from the discharge lamp becomes a desired value without changing the output voltage of the first converter when dimming to reduce the output to the desired value After the power is lowered, after the lighting state of the discharge lamp is stabilized, the second converter is accompanied with the reduction of the output voltage of the first converter so as to keep the light output from the discharge lamp at the desired value. To discharge lamp It is intended to increase the supply power.
[0011]
According to a second aspect of the present invention, in the first aspect of the invention, the first converter has a function of improving an input power factor. In the control circuit, the input power factor is set to a lower limit of the output voltage of the first converter. and the voltage can be maintained greater than or equal to the prescribed level, during the output voltage of the first converter is the lower limit or more is dimming by the output voltage of the first converter, the state in which the output voltage of the first converter is the lower limit When dimming deeper than that, the power supplied from the second converter to the discharge lamp is reduced.
[0012]
According to a third aspect of the present invention, in the first aspect of the present invention, the control circuit is configured such that the light output from the discharge lamp becomes a desired value without changing the output voltage of the first converter during dimming. Prior to lowering the power supplied from the converter to the discharge lamp, the output voltage of the first converter is set higher than that before dimming without changing the power supplied from the second converter to the discharge lamp. .
[0013]
According to a fourth aspect of the present invention, in the first aspect of the present invention, when the light control depth exceeds a predetermined value in the light control, the control circuit does not change the output voltage of the first converter from the discharge lamp. Prior to lowering the power supplied from the second converter to the discharge lamp so that the light output becomes a desired value, the output voltage of the first converter without changing the power supplied from the second converter to the discharge lamp. Is set higher than before dimming.
[0014]
According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, each of the first converter and the second converter is a chopper circuit.
[0015]
The invention of claim 6 is characterized in that, in the invention of claim 5, the first chopper circuit is a step-up chopper circuit.
[0016]
The invention of claim 7 is the invention of claim 5 or claim 6, wherein the second chopper circuit is a step-down chopper circuit.
[0017]
The invention of claim 8 is characterized in that, in the inventions of claims 1 to 7, the discharge lamp is a high pressure discharge lamp.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing the overall configuration of the present embodiment. The main difference from the conventional configuration shown in FIG. 7 is that two chopper circuits 1 and 2 are sequentially connected in place of the choke coil L11, the dimming choke coil L12, the autotransformer T11 constituting the igniter 11, and the like. It is a so-called active-to-converter system (cascade connection), which realizes functions as a ballast circuit and a dimming choke coil L12. Further, the lamp La is configured to be lit in direct current. However, in this embodiment, since the function of the igniter 11 is not a gist, explanation is omitted.
[0019]
Therefore, in the present embodiment, the rectifier circuit 5 is connected to the AC power supply AC such as a commercial power supply via the terminals TM1 and TM2, and the pulsating voltage output from the rectifier circuit 5 is input to the chopper circuit 1 to be DC- DC conversion. The chopper circuit 2 functions as a current limiting circuit that controls the power supplied to the lamp La, which is a high pressure discharge lamp, using the output of the chopper circuit 1 as a power source. That is, the chopper circuit 1 controls the voltage applied to the lamp La, and the chopper circuit 2 controls the supply current to the lamp La. The outputs of the chopper circuits 1 and 2 are controlled by the control circuit 3. The control circuit 3 is connected to a conversion circuit 4 that converts a dimming signal (for example, a pulse train) input from the outside through terminals TM3 and TM4 into a format that can be received by the control circuit 3. The chopper circuit 1 outputs a voltage necessary for maintaining the lighting state of the lamp La, and the chopper circuit 2 controls the power supplied to the lamp La. As will be described later, the chopper circuits 1 and 2 are provided with switching elements, and these switching elements are turned on and off at a frequency sufficiently higher than the power supply frequency of the AC power supply AC. A filter circuit for preventing high frequency (not shown) is provided between the AC power supply AC and the rectifier circuit 5 so as not to leak into the line.
[0020]
Specific examples of the configurations of the chopper circuits 1 and 2 will be described. In the present embodiment, a step-up chopper circuit is employed as the chopper circuit 1 and a step-down chopper circuit is employed as the chopper circuit 2 as shown in FIG. The rectifier circuit 5 is a full-wave rectifier circuit composed of a diode bridge. The chopper circuit 1 connects a series circuit of an inductor L1 and a switching element Q1 between the DC output terminals of the rectifier circuit 5, and a diode D1 and a smoothing capacitor C1. Is connected between both ends of the switching element Q1. The switching element Q1 is turned on and off by the control circuit 3 via the drive circuit 6. The drive circuit 6 converts the control signal from the control circuit 3 into a voltage signal suitable for controlling the switching element Q1 made of MOSFET. The diode D1 is connected to a polarity capable of charging the smoothing capacitor C1 from the rectifier circuit 5 through the inductor L1. That is, it is connected in the forward direction with respect to the output of the rectifier circuit 5.
[0021]
On the other hand, the chopper circuit 2 has a series circuit of a switching element Q2, an inductor L2, and a capacitor C3 connected between both ends of the smoothing capacitor C1, and a diode D2 is connected in parallel to the series circuit of the inductor L2 and the capacitor C3. The inductor L3 which comprises the filter circuit F with C3 is provided. The diode D2 is connected to a polarity that blocks a discharge current from the smoothing capacitor C1 in a closed loop of the smoothing capacitor C1, the switching element Q2, and the diode D2. Further, the inductor L3 constituting the filter circuit F is configured such that a series circuit with the lamp La is connected between both ends of the capacitor C3. That is, the filter circuit F is a low-pass filter, and is provided so as to block high frequency from the chopper circuit 2 to the lamp La. The switching element Q2 is made of a MOSFET and is controlled by the control circuit 3 via the drive circuit 7. The drive circuit 7 converts the control signal from the control circuit 3 into a voltage signal suitable for controlling the switching element Q2.
[0022]
However, in the chopper circuit 1, when the switching element Q1 is turned on / off, the energy accumulated in the inductor L1 when the switching element Q1 is turned on is released via the diode D1 when the switching element Q1 is turned off, and is output to the output of the rectifier circuit 5. The smoothing capacitor C1 is charged in a manner in which energy released from the inductor L1 is superimposed, and the voltage across the smoothing capacitor C1 can be boosted above the output voltage of the rectifier circuit 5. In the chopper circuit 2, when the switching element Q2 is turned on / off, power is supplied to the lamp La through the inductor L2 and the filter circuit F when the switching element Q2 is turned on, and is stored in the inductor L2 and the filter circuit F when the switching element Q2 is turned off. The emitted energy is discharged to the lamp La through the diode D2. That is, the current to the lamp La is controlled by turning on / off the switching element Q2. Switching elements Q1, Q2 are turned on and off at a frequency sufficiently higher than the power supply frequency of AC power supply AC. The configuration and operation of this type of step-up chopper circuit and step-down chopper circuit are conventionally known and will not be described in detail here.
[0023]
As described above, when the two-stage chopper circuits 1 and 2 are sequentially connected, it is possible to reduce the circuit loss by setting the output voltage of the first-stage chopper circuit 1 as low as possible while ensuring the necessary voltage. Can be reduced. That is, when the voltage handled in the chopper circuit 2 is increased, switching loss and the like are increased. Therefore, it is desirable that the output voltage of the chopper circuit 1 is low. However, when the full lighting state is shifted to the dimming lighting state, the voltage across the lamp La temporarily increases and then decreases.
[0024]
Therefore, in this embodiment, the control circuit 3 is configured so that the chopper circuits 1 and 2 are controlled as follows. That is, as shown in FIG. 3, the lamp La is lit in the fully lit state until time t1, and a dimming signal is input from the outside so as to dim 50% with respect to the fully lit state at time t1. Suppose. The dimming signal is input to the control circuit 3 through the conversion circuit 4, and the control circuit 3 reduces the power supplied to the lamp La to 50% from the fully lit state (that is, the light output is reduced to 50% of the fully lit state). Start the control. At time t1 when the dimming signal is input, the output voltage of the chopper circuit 1 does not change as shown in FIG. 3A, and only the output of the chopper circuit 2 passes over time as shown in FIG. It controls so that it may reduce with this. If the output of the chopper circuit 2 is lowered, the power supplied to the lamp La is reduced, so that the light output of the lamp La is lowered. The time T1 from when the dimming signal is input until the light output of the lamp La reaches 50% is longer than the period during which the applied voltage to the lamp La changes and the lamp La is in a transiently unstable state. Set longer. Thus, from time t2 after the time T1 has elapsed, the output voltage of the chopper circuit 1 is decreased with time in order to reduce the output voltage of the chopper circuit 1 while maintaining the dimming state of the lamp La. At the same time, the output of the chopper circuit 2 is increased with time. That is, after the output of the chopper circuit 2 is reduced and the lamp La is dimmed by 50%, the output voltage of the chopper circuit 1 is reduced and the chopper circuit 2 Simultaneously increase output. Thus, the output voltage of the chopper circuit 1 is lowered to a desired voltage, and the output voltage of both the chopper circuits 1 and the output of the chopper circuit 2 are kept constant after time t3 when the output voltage of the chopper circuit 1 reaches the desired voltage. To do.
[0025]
By controlling the chopper circuits 1 and 2 as described above, the lamp La is shifted to the dimming state and the lamp La is unstable. Dimming can be performed without lowering the lighting maintenance voltage required for La, thereby preventing the lamp La from turning off. Moreover, after the lamp La is stabilized, the lighting sustaining voltage, which is the output voltage of the chopper circuit 1, is lowered, so that the loss of the entire circuit can be reduced.
[0026]
By the way, when the light control is made deeper, for example, when the light control is made deeper than 25% to 25%, the control is performed as shown in FIG. In FIG. 4, the control up to time t3 is the same as the control up to time t3 shown in FIG. 3, and the light is adjusted to 50% at this time. At this time, the output voltage of the chopper circuit 1 is lower than that in the fully lit state, and the output of the chopper circuit 2 is set to about the output voltage in the fully lit state. Here, when a dimming signal indicating 25% is input to the conversion circuit 4 at time t4 after time t3, the output voltage of the chopper circuit 1 is not changed, and only the output of the chopper circuit 2 elapses. Decrease with it. In this case, the light output of the lamp La is reduced only by reducing the output of the chopper circuit 2, and stable lighting is achieved after the transient state of the lamp La.
[0027]
Whether the output voltage of the chopper circuit 1 is changed at time t2 or not after time t4 in response to the instruction of the dimming signal is designed according to the ability of the chopper circuit 1. That is, after time t3 in FIG. 4, the case where the capacity of the chopper circuit 1 is a limit that can maintain the input power factor at or above a predetermined level (a level required by a standard or the like as this kind of lighting fixture) is shown. In such a case, if the output voltage of the chopper circuit 1 is lowered, the input power factor cannot be maintained at a predetermined level. Therefore, only the output of the chopper circuit 2 is lowered without lowering the output voltage of the chopper circuit 1, and the lamp La Dimming.
[0028]
As described above, within a range in which the input power factor can be maintained at a predetermined level even when the output voltage of the chopper circuit 1 is lowered, the chopper circuit 2 is in a period in which the lamp La is unstable immediately after the dimming is started. The output voltage of the chopper circuit 1 is temporarily maintained but the output voltage of the chopper circuit 1 is maintained to ensure a lighting maintaining voltage, and thereafter, the output voltage of the chopper circuit 2 is increased and adjusted as the output voltage of the chopper circuit 1 is decreased. Maintain light condition. When the output voltage of the chopper circuit 1 cannot be reduced to the depth indicated by the dimming signal even if the output voltage of the chopper circuit 1 is reduced to the limit where the input power factor can be maintained at a predetermined level, the output voltage of the chopper circuit 1 is reduced, The output of the chopper circuit 2 is also reduced to adjust the light to a desired depth.
[0029]
With such an operation, when the lamp La immediately after dimming is unstable, dimming is performed without lowering the lighting maintenance voltage required for the discharge lamp La, and turning off is prevented, and the input power factor exceeds a predetermined level. The circuit loss can be reduced by reducing the lighting maintenance voltage and performing dimming lighting while the lamp La is stably lit.
[0030]
The control shown in FIG. 5 may be adopted as the control for deepening the light control. In FIG. 5, as in the example shown in FIG. 4, the case where the light is adjusted from 25% to 25% will be described as an example. That is, the operation before time t4 is the same as the operation shown in FIG. 4, the output voltage of the chopper circuit 1 is lower than the voltage in the fully lit state, and the output of the chopper circuit 2 is the voltage in the fully lit state. It is assumed that the degree is set. When the dimming signal is input to the conversion circuit 4 so that the dimming is performed at 25% at time t4, the control circuit 3 performs control so that the output voltage of the chopper circuit 1 is increased. At this time, the output of the chopper circuit 2 is not changed. As described above, the lamp La becomes unstable by increasing the output voltage of the chopper circuit 1. However, since the high voltage can be applied to the lamp La by increasing the voltage, the lamp La does not disappear. Thereafter, at time t5, the output of the chopper circuit 2 is decreased with time to adjust the light output of the lamp La, and when the light output of the lamp La reaches 25%, the light of the lamp La starts from time t6. The output of the chopper circuit 2 is increased as the output voltage of the chopper circuit 1 is lowered so as to keep the output constant. Thus, when the output voltage of the chopper circuit 1 and the output of the chopper circuit 2 reach the target values, the output voltage is maintained and the light output of the lamp La is maintained at 25% with respect to the fully lit state.
[0031]
If the output voltage of the chopper circuit 1 and the output of the chopper circuit 2 are controlled as shown in FIG. 5, the lighting maintenance voltage of the lamp La is temporarily increased, so that the lamp La can be reliably prevented from extinguishing. In a stable state, the lighting sustain voltage, which is the output voltage of the chopper circuit 1, is lowered, so that circuit loss can be reduced.
[0032]
In the configuration example described above, a step-up chopper circuit is used as the chopper circuit 1 and a step-down chopper circuit is used as the chopper circuit 2. However, the configuration of each chopper circuit 1 and 2 is not particularly limited, and the chopper circuit 1 is an AC power source. Any circuit may be used as long as the input power factor from the AC can be maintained at a predetermined level or more and the output voltage is variable, and the chopper circuit 2 may be any circuit as long as the output is variable. For example, as shown in FIG. 6, even if a step-up chopper circuit is used for the chopper circuit 1 in order to maintain the input power factor at a high power factor, the chopper circuit 2 has a chopper circuit other than the step-down chopper circuit (step-up chopper circuit). A chopper circuit, a polarity inversion chopper circuit, or the like can be used. Alternatively, another chopper circuit may be used for the chopper circuit 1. Furthermore, a DC-DC converter such as a flyback type can be used in place of the chopper circuits 1 and 2.
[0033]
【The invention's effect】
According to the first aspect of the present invention, there is provided a rectifier circuit for rectifying an AC power source, a first converter for converting the output voltage of the rectifier circuit and changing the output voltage, and an output of the first converter as a power source to a discharge lamp. And a control circuit that controls the output voltage of the first converter and the power supplied from the second converter to the discharge lamp. In the control circuit, the light of the discharge lamp Supplying from the second converter to the discharge lamp so that the light output from the discharge lamp becomes a desired value without changing the output voltage of the first converter when dimming the output to a desired value. After the power is lowered, after the lighting state of the discharge lamp is stabilized, the second converter is accompanied with the reduction of the output voltage of the first converter so as to keep the light output from the discharge lamp at the desired value. To discharge lamp Immediately after the start of dimming, the applied voltage to the discharge lamp is not changed and maintained at a high voltage to prevent extinction, and the unstable period of the discharge lamp has elapsed. After that, the circuit loss can be reduced by lowering the output voltage of the first converter.
[0034]
According to a second aspect of the present invention, in the first aspect of the invention, the first converter has a function of improving the input power factor, and the control circuit determines the lower limit of the output voltage of the first converter as the input power factor. and the voltage can be maintained more than the specified level, during the output voltage of the first converter is the lower limit or more is dimming by the output voltage of the first converter, the state in which the output voltage of the first converter is the lower limit When dimming deeper, the power supplied from the second converter to the discharge lamp is reduced, and the input power factor is maintained by the first converter while the supply from the second converter to the discharge lamp is performed. By controlling the power, deep dimming is possible.
[0035]
According to a third aspect of the present invention, in the first aspect of the present invention, the control circuit is configured such that the light output from the discharge lamp becomes a desired value without changing the output voltage of the first converter during dimming. Prior to reducing the power supplied from the converter to the discharge lamp, the output voltage of the first converter is set higher than that before dimming without changing the power supplied from the second converter to the discharge lamp. Since the output voltage of the first converter is temporarily increased immediately after the start of dimming, it is possible to reliably prevent the discharge lamp from extinguishing immediately after the start of dimming.
[0036]
According to a fourth aspect of the present invention, in the first aspect of the present invention, when the light control depth exceeds a predetermined value in the light control, the control circuit does not change the output voltage of the first converter from the discharge lamp. Prior to lowering the power supplied from the second converter to the discharge lamp so that the light output becomes a desired value, the output voltage of the first converter without changing the power supplied from the second converter to the discharge lamp. Is set higher than that before dimming, and the output voltage of the first converter is temporarily increased immediately after dimming starts, so that it is possible to reliably prevent the discharge lamp from extinguishing immediately after dimming starts. .
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a circuit diagram of the above.
FIG. 3 is an operation explanatory diagram of the above.
FIG. 4 is an operation explanatory diagram when the dimming is deepened in the above.
FIG. 5 is an operation explanatory diagram of another operation when the light control is deepened in the same as above.
FIG. 6 is a circuit diagram of the above.
FIG. 7 is a diagram showing a conventional example.
FIG. 8 is a circuit diagram showing another conventional example.
FIG. 9 is a circuit diagram showing still another conventional example.
[Explanation of symbols]
1 Chopper circuit 2 Chopper circuit 3 Control circuit 5 Rectifier circuit AC AC power supply La Lamp

Claims (8)

A rectifier circuit that rectifies an AC power supply, a first converter that converts the output voltage of the rectifier circuit and converts the output voltage, and an output power of the first converter is used as a power source, and power supplied to the discharge lamp is variable. The control circuit includes a second converter and a control circuit that controls the output voltage of the first converter and the power supplied from the second converter to the discharge lamp. The control circuit reduces the light output of the discharge lamp to a desired value. After dimming the power supply from the second converter to the discharge lamp so that the light output from the discharge lamp becomes a desired value without changing the output voltage of the first converter, After the lighting state of the discharge lamp is stabilized, the power supplied from the second converter to the discharge lamp as the output voltage of the first converter is lowered so as to keep the light output from the discharge lamp at the desired value. The rise The discharge lamp lighting device according to claim Rukoto. The first converter has a function of improving the input power factor. In the control circuit, the lower limit of the output voltage of the first converter is set to a voltage at which the input power factor can be maintained above a specified level, and the first converter When the output voltage of the first converter is higher than the lower limit, dimming is performed with the output voltage of the first converter, and when dimming deeper than the state where the output voltage of the first converter is lower than the lower limit, the light is emitted from the second converter. The discharge lamp lighting device according to claim 1, wherein power supplied to the electric lamp is reduced. In the control circuit, prior to reducing the power supplied from the second converter to the discharge lamp so that the light output from the discharge lamp becomes a desired value without changing the output voltage of the first converter during dimming. The discharge lamp lighting device according to claim 1, wherein the output voltage of the first converter is set higher than that before dimming without changing the power supplied from the second converter to the discharge lamp. In the control circuit, when the dimming depth exceeds a predetermined value during dimming, the second converter converts the light output from the discharge lamp to a desired value without changing the output voltage of the first converter. Prior to lowering the power supplied to the discharge lamp, the output voltage of the first converter is set higher than that before dimming without changing the power supplied from the second converter to the discharge lamp. The discharge lamp lighting device according to claim 1. The discharge lamp lighting device according to any one of claims 1 to 4, wherein each of the first converter and the second converter is a chopper circuit. 6. The discharge lamp lighting device according to claim 5, wherein the first chopper circuit is a step-up chopper circuit. The discharge lamp lighting device according to claim 5 or 6, wherein the second chopper circuit is a step-down chopper circuit. The discharge lamp lighting device according to any one of claims 1 to 7, wherein the discharge lamp is a high-pressure discharge lamp.

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