JP2001338789A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device, capable of suitably starting a discharge lamp with a high-voltage pulse voltage obtained by LC resonance and supplying the energy necessary for smooth transfer to arc discharge to the discharge lamp. SOLUTION: This discharge lamp lighting device comprises a DC power source 1A; a load resonance circuit 2A comprising an inductor L1, a capacitor C1 and a discharge lamp La; an inversion circuit 3A comprising the serial connection of at least first and second switching elements connected, in parallel with the DC power source 1A, which converts the DC power from the DC power source 1A into AC power and supplies it to the load resonance circuit 2A; and a control circuit 5A for alternately causing each switching element turn on/off at high frequency, so as to alternately generate a first period where the on-period of the second switching element is longer than that of the first switching element and a second period where the on-period of the second switching element is shorter to apply a rectangular wave-like low frequency voltage to the discharge lamp La. The control circuit 5A superposes the DC component of the output of the inversion circuit 3A to the resonance pulse from the load resonance circuit 2A and continuously changes the switching frequency of each switching element for a prescribed time from the start of one of the first and second periods.

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 having high startability, and more particularly to a high-intensity discharge lamp (HID lamp).
The present invention relates to a discharge lamp lighting device with improved startability and reduced stress on each component.

[0002]

2. Description of the Related Art For example, a conventional discharge lamp lighting device described in Japanese Patent Application Laid-Open No. 63-150895 has first and second transistors for high frequency operation and third and fourth transistors for low frequency operation. A transistor, a control circuit for on / off control of the first to fourth transistors, and an igniter for generating a high-voltage pulse voltage are provided. Apply to the light.

[0003] The control circuit in the above-described device includes a first circuit to which first and second reference voltages Vr1 and Vr2 are applied, respectively.
An oscillator circuit for oscillating a clock signal of a predetermined frequency set by a time constant circuit comprising a capacitor and a resistor; a first flip-flop inverted by an output of each comparator; It is composed of a timer circuit that outputs a pulse signal, and a drive circuit that forms control signals for two pairs of transistors based on a flip-flop output (high-frequency signal fh) and a timer circuit output (low-frequency signal f1).

[0004] The drive circuit is formed of a second flip-flop, first to fourth AND circuits, fifth and sixth transistors, and first and second pulse transformers.

The igniter includes a bidirectional three-terminal thyristor (triac), a bidirectional two-terminal switch (switch), a third pulse transformer, and the like. The triac is turned on / off when the discharge lamp is started. A high-voltage pulse for starting induced in the secondary winding of the third pulse transformer is applied to the discharge lamp via the first capacitor.

The operation of this discharge lamp lighting device will be described. The output of the oscillation circuit is compared with a second reference voltage Vr2 by a second comparator, and when the output of the oscillation circuit becomes larger than the second reference voltage, The second comparator output goes high, the first flip-flop is set and its output goes high. From this moment the first and third
One of the transistors turns on and current flows,
A voltage Vdt corresponding to the current is generated at both ends of the current detection resistor. This voltage Vdt and the first reference voltage Vr1
The first comparator output goes high when Vdt> Vr1 and the first comparator output goes high.
Are reset.

The high-frequency signal fh output from the first flip-flop is input to the drive circuit as a timing signal for a high-frequency switching operation. On the other hand, the low-frequency signal f1 output from the timer circuit is input to the drive circuit as a timing signal for the low-frequency switching operation, and is set to twice the frequency of the polarity inversion frequency.

In the drive circuit, the low frequency signal f1 is transmitted to the second
And the third and fourth AND circuits to divide the frequency to form and output ON control signals for the third and fourth transistors, and to output the first and second AND circuits by the high frequency signal fh. The output is appropriately set to a high level to output on / off control signals for the first and second transistors via the fifth and sixth transistors and the second and third pulse transformers. Therefore, the AC voltage output from the inverter of the full bridge configuration and applied to the discharge lamp via the inductor has a polarity inverted at a constant cycle, and becomes a voltage chopped at a high frequency.

[0009] In the igniter, the second capacitor is charged before the polarity inversion, and after the polarity inversion, the third capacitor is charged via a resistor. In accordance with a time constant determined by the resistance of the second capacitor and the fourth capacitor. That is, when the voltage across the fourth capacitor reaches the response voltage of the switch, the switch is turned on and the triac is triggered. When the triac conducts in this way, the second,
A third capacitor is connected in series, and the charged charge is discharged through the primary winding of the first transformer. A high-voltage pulse for starting is generated in the secondary winding and applied to the discharge lamp. You.

[0010]

However, in the above-mentioned known discharge lamp lighting device, the polarity reversal cycle of the AC voltage applied to the discharge lamp is the same cycle (switching frequency) both at startup (at the start of discharge) and at steady lighting. Is 100-200Hz)
Therefore, even when a high-voltage pulse voltage is applied at the time of starting and the discharge lamp starts to start, the reverse polarity voltage is immediately applied, and it becomes difficult to maintain the discharge, and a smooth transition to steady lighting can be performed. However, there was a problem that the starting characteristics were poor.

A control circuit proposed as one improvement in the above known device further includes a third flip-flop and elements connected to the periphery thereof in addition to the configuration of the control circuit. When the load is not started, the output of the first comparator is always set to the low level so that electric charges are not stored in the peripheral capacitors, the transistor is turned off, and the output of the third flip-flop is set to the low level. When the level reaches the level, the third resistor is inserted, and the polarity inversion cycle of the AC voltage is made sufficiently long (for example, 10
Hz or less). Therefore, in this discharge lamp lighting device, when the discharge is about to be applied by the application of the high voltage pulse voltage, the voltage of the same polarity is applied for a sufficiently long time, so that it is possible to easily shift to a stable discharge and the starting characteristics are improved. However, in a discharge lamp lighting device provided with a control circuit as such an improvement measure, the interval of the high-voltage pulse voltage applied to the discharge lamp becomes long because the polarity inversion cycle of the AC voltage is long over the entire starting time. However, there is a problem that the starting time becomes long.

Another solution is to generate a high-voltage pulse by means of an LC resonance voltage. For example, a set of first and fourth transistors and a set of second and third transistors are alternately set to 50. When it is turned on / off with an on-duty of%, it becomes possible to apply a continuous high-voltage pulse voltage of the same level due to LC resonance to the discharge lamp. However, in this method, since the voltage applied to the discharge lamp does not include a DC component, there is a problem that energy required for smoothly shifting to arc discharge after dielectric breakdown cannot be obtained.

In order to obtain a high-voltage pulse voltage, the switching frequency may be set near the LC resonance frequency. In this case, however, a large resonance current needs to flow, and a large stress is applied to coils, capacitors, switching elements, and the like. The problem arises.

[0014] In view of the above, the present invention suitably starts and lights a discharge lamp with a high-voltage pulse obtained by LC resonance, and supplies the discharge lamp with energy necessary for smoothly shifting to arc discharge. An object of the present invention is to provide a discharge lamp lighting device that improves startability and reduces costs for components such as a coil, a capacitor, and a switching element.

[0015]

SUMMARY OF THE INVENTION The present invention provides a DC power supply circuit for supplying DC power having a pair of output terminals, and at least first and second series-connected DC power supply circuits connected in parallel with the output terminals of the DC power supply circuit. A polarity inversion circuit including a switching element and converting DC power from a DC power supply circuit into AC power; a load resonance circuit including an inductor, a capacitor and a discharge lamp connected in parallel to the capacitor; and first and second polarity inversion circuits. And a control circuit for alternately turning on / off the two switching elements to control the voltage applied to the discharge lamp of the load resonance circuit. Then, the control circuit alternates the first and second switching elements such that the first period and the second period in which the ON period is longer in the second switching element than in the first switching element are alternately generated. A high-frequency operation is performed to turn on / off a rectangular wave-like low-frequency voltage to the discharge lamp, and a DC component is superimposed on a resonance pulse from a load resonance circuit in a starting lighting mode of the discharge lamp, so that the switching frequency of each switching element is changed. Is controlled so that a high voltage is applied to the discharge lamp by continuously changing.

Thus, the discharge lamp is suitably started and lit by the high-voltage pulse voltage obtained by the LC resonance, and the energy necessary for smoothly shifting to the arc discharge is supplied to the discharge lamp to improve the startability. And coils,
Reduce the cost of components such as capacitors, switching elements, etc.

[0017]

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

FIG. 1 is a schematic block diagram of a discharge lamp lighting device according to a first embodiment of the present invention. The lighting device for discharge etc. according to the present embodiment includes a DC power supply circuit 1A that converts AC power from an AC power supply AC into DC power and supplies the DC power to a pair of output terminals, and desirably, an output terminal of the DC power supply circuit 1A. A polarity inversion circuit 3A for converting DC power from the DC power supply circuit 1A into AC power, including first and second capacitors and first and second switching elements connected in series, and desirably an inductor; And a capacitor connected in series and a load resonance circuit 2A including a discharge lamp connected in parallel to the capacitor and receiving the AC power from the polarity inversion circuit 3A, and the switching elements of the polarity inversion circuit alternately turned on / off to form a discharge lamp. And a control circuit 5A for controlling the voltage supplied to the control circuit 5A.

The control circuit 5A includes a first period in which the on-period of the second switching element is longer than an on-period of the first switching element, and a control circuit for the second switching element, which is longer than the on-period of the first switching element. The two switching elements are alternately turned on / off at a high frequency so as to generate the second period in which the on-period is shortened, so that the duty of the switching elements is controlled to be unbalanced, the on / off frequency is changed, and the on / off frequency is changed. A rectangular wave low frequency voltage is applied to the lamp. That is, the control circuit 5A changes the frequency of each switching element and applies a high voltage to the discharge lamp in at least one of the first and second periods.

In this configuration, since the switching frequency changes, a high-voltage pulse voltage which becomes maximum when the LC resonance by the inductor and the capacitor reaches a peak is applied to the discharge lamp. As a result, the discharge lamp is suitably started and lit. Also, the first and second switching elements alternately generate a high frequency so that a first period in which the second switching element has a longer ON period and a second period in which the second switching element has a shorter ON period are alternately generated. Since it is turned on / off by the operation, a rectangular wave-like low frequency voltage is applied to the discharge lamp, and energy capable of smoothly shifting to arc discharge is supplied to the discharge lamp. As a result, the discharge lamp can be suitably started and lit with the high-voltage pulse voltage obtained by LC resonance, and the energy necessary for smoothly shifting to arc discharge is supplied to the discharge lamp to improve the startability. It becomes possible to do.

FIG. 2 is a specific circuit diagram of the discharge lamp lighting device of the first embodiment shown in FIG. The discharge lamp lighting device shown in FIG. 2 includes a DC power supply 1A having a step-up chopper circuit 11A for supplying DC power, an inductor L1, a capacitor C1 connected in series with the inductor L1, and a series connected in parallel with the capacitor C1. A load resonance circuit 2A including a connected discharge lamp (high-intensity discharge lamp) La and a resistor R1, and a polarity inversion circuit 3A that converts DC power from the DC power supply 1A into AC power and supplies the AC power to the load resonance circuit 2A.
And a control circuit 4A for the boost chopper circuit 11A and a control circuit 5A for the polarity inversion circuit 3A.

The DC power supply 1A is composed of a rectifier DB that takes in AC power from an AC power supply AC and rectifies the AC power, and a boost chopper circuit 11A.
Is an inductor L11 having one end connected to the high-potential-side output terminal of the rectifier DB, and a switching element such as an FET having a drain and a source connected to the other end of the inductor L11 and the low-potential-side output terminal of the rectifier DB, respectively. Q11 and a diode D11 to which the other end of the inductor L11 and the anode are connected. However, the switching element Q11 has a structure in which a source / substrate is connected, and a parasitic diode D11 whose cathode and anode are connected to the drain and source, respectively.

The polarity inversion circuit 3A includes a diode D3 connected in series with the output of the DC power supply 1A, for example, a diode F3.
A first switching element Q1 made of ET and a diode D
4 and a second switching element Q2 comprising an FET;
A diode D5 connected in parallel with the diode D3 and the first switching element Q1, a diode D6 connected in parallel with the diode D4 and the second switching element Q2, and a series connected diode connected in parallel with the output of the DC current 1A. 1, and second capacitors CE1 and CE2. However, the first and second switching elements Q1, Q2
Is the same as the switching element Q11 of the boost chopper circuit.
It has parasitic diodes D1 and D2, respectively.

The control circuit 4A for the boost chopper circuit includes an output voltage detection circuit 41 for detecting the output voltage of the boost chopper circuit 11A, and a drive circuit 42 for receiving the detection signal and driving the switching element Q11. The on / off control is performed on the switching element Q11 by generating and outputting a control signal for on / off. Further, for example, in the same manner as in the related art, control is performed to monitor the output voltage of the boost chopper circuit 11A and perform on / off control of the switching element Q11 to boost the output voltage of the rectifier DB to a predetermined level.

The control circuit 5A for the polarity reversing circuit 3A calculates the lamp power by receiving detection signals from the Vla detection circuit 51 for detecting the lamp voltage, the Ila detection circuit 52 for detecting the lamp current, and both detection circuits. Wla detection circuit 5
3, and a drive circuit 54 that receives the calculation signal and drives the first and second switching elements Q1 and Q2, and controls the first and second switching elements Q1 and Q2 for ON / OFF. On / off control is performed by generating and outputting a signal.

For example, when the discharge lamp La is in a steady state, the on-duty for adjusting the lamp power obtained from the Wla detection circuit 53 to a predetermined value is used as shown in TM21 and TM22 in FIG. , During the period TM21,
While the first switching element Q1 is turned on / off by high-frequency operation of several tens of kHz while the second switching element Q2 is kept off, the first switching element Q1 is kept off during the next period TM22. Control for turning on / off the second switching element Q2 by high-frequency operation of several tens of kHz is repeatedly performed. In this case, the periods TM21, T
The frequency of M22 is set to a low frequency of several tens to hundreds Hz. Also, the first and second switching elements Q1,
The switching frequency of Q2 is maintained at a constant value.

On the other hand, in the case of the control mode for starting and lighting in which the discharge lamp La is started and lit in contrast to the control mode for the steady state described above, the ON period is set to the second switching element Q1 from the second switching element Q1. Both switching elements Q1 and Q2 are generated such that first period TM12 in which switching element Q2 is longer and second period TM11 in which switching element Q2 is shorter are alternately generated.
Are alternately turned on / off by a high-frequency operation to apply a rectangular-wave low-frequency voltage to the discharge lamp La. In this case, the frequency formed by the periods TM11 and TM12 is set to a low frequency of several tens to hundreds Hz.

As shown in "Duty sweep" in FIG. 3, control is performed to continuously change, that is, sweep, the on-duty ratio from the start of each of the periods TM11 and TM12 to a predetermined time T1. .
At this time, the longer ON period, that is, Q
1. In TM12, when each ON period of Q2 is gradually increased over a predetermined time T1, the DC component of the lamp voltage Vla gradually increases. In the example of FIG. 3, the ON period outside the predetermined time T1 is longer than the ON period within the predetermined time T1.

Further, the first and second switching elements Q in at least one of the first and second periods are provided.
1, by changing the switching frequency of Q2, discharge lamp L
Control for applying a high voltage to a is performed. That is, the control circuit 5A, as shown in the "frequency sweep" of FIG.
The first and second switching elements Q are provided for a predetermined time T1 from the start of each of the periods TM11 and TM12.
1. Control to change (sweep) the switching frequency of Q2. At this time, the sweep range is set to include the peak of the LC resonance by the inductor L1 and the capacitor C1. Note that the slopes of the switching frequencies of the first and second switching elements Q1 and Q2 may be substantially the same.

Next, the operation of the control circuit 5A, which is a feature of the first embodiment, will be briefly described. First, the circuit operation in the control mode for the steady state will be described with reference to FIG. 3. In the period TM21, the first switching element Q2 is kept off while the second switching element Q2 is kept off.
1 is turned on / off by high frequency operation, while the period TM22
In the above, the control for turning on / off the second switching element Q2 by high-frequency operation while the first switching element Q1 is kept off is repeatedly performed, whereby the rectangular wave low-frequency voltage Vla is applied to the discharge lamp La. As a result, a rectangular wave-like low frequency current Ila flows, and the discharge lamp La is turned on in a steady state.

Next, the circuit operation in the control mode for starting lighting will be described. The second switching element Q2
Is controlled so that the first and second switching elements Q1 and Q2 are alternately turned on / off by a high-frequency operation so as to alternately generate a period TM12 in which the ON period is longer than the first switching element Q1 and a period TM11 in which the ON period is shorter. As a result, a rectangular wave-like low-frequency voltage is applied to the discharge lamp La, and the DC component included in the lamp voltage Vla sufficiently supplies the discharge lamp La with energy necessary for shifting to arc discharge. become.

At this time, as shown in FIG. 3, the on-duty ratio is changed from D11 to D1 from a start time in each of the periods TM11 and TM12 to a predetermined time T1.
2, the DC component of the lamp voltage Vla gradually increases. However, the on-duty ratio D12 is returned to D11 at the start of each of the periods TM11 and TM12.

Further, as shown in FIG.
1, a predetermined time T from the start time in each period of TM12
1, the first and second switching elements Q1, Q2
Is performed to change the switching frequency from f11 to f12. When the LC resonance by the inductor L1 and the capacitor C1 reaches a peak, the high-voltage pulse voltage which becomes maximum is superimposed on the lamp voltage Vla. The electric lamp La is suitably started and lit when dielectric breakdown occurs. Further, by sweeping the switching frequency, it becomes possible to apply a high-voltage pulse voltage, which is maximized even when the component constants vary, to the discharge lamp La. However, the switching frequency f12 is different from the period T1
At the start of each period of T1, T12, it is returned to f11.

As described above, according to the first embodiment, the discharge lamp can be suitably started and lit by the high-voltage pulse voltage obtained by the LC resonance circuit, and is necessary for smoothly shifting to arc discharge. Energy can be supplied to the discharge lamp to improve startability.

In the first embodiment, in the control mode for starting lighting, as shown in FIG. 3, the switching frequencies of the first and second switching elements Q1 and Q2 are changed from low to high. The configuration is such that the switching frequency is swept from the higher switching frequency to the lower switching frequency of both switching elements Q1 and Q2. In short, both switching elements Q1, Q2
4, the control circuit for changing the switching frequency of both switching elements Q1 and Q2 in at least one of the first and second periods to one of a lower one and a higher one, as shown in FIG. As a result, the peak voltage of the lamp voltage Vla of the discharge lamp La and the voltage growth process can be stabilized.

In the above description, the switching element Q
1. Although FETs, especially MOSFETs, are used as Q2, transistors may be used.

FIG. 5 is an explanatory diagram of a frequency sweep in the discharge lamp lighting device according to the second embodiment of the present invention.
The discharge lamp lighting device includes a DC power supply 1A, a load resonance circuit 2A,
Polarity inverting circuit 3A and control circuit 4 for each circuit 2A, 3A
A and 5A are provided in the same manner as in the first embodiment of FIG. 2, but the difference from the first embodiment is that the control circuit 5B for the polarity reversing circuit in this embodiment is different from the first embodiment. In the control mode of the first embodiment, except that control is performed to change the switching frequency of the first and second switching elements Q1 and Q2 to a lower one in at least one of the periods TM11 and TM12. 5A
The configuration is the same as That is, this control circuit 5B
Each switching element Q1, Q2 is switched from a start point in each of the periods TM11, TM12 to a predetermined time T1.
The switching frequency of the higher f12 to the lower f11
, That is, a sweeping control is performed.

Next, the reason why the control circuit 5B sweeps the switching frequency to the lower side will be described with reference to FIG. When the discharge lamp La breaks down, the load resonance circuit 2
The resonance curve at A changes from the resonance curve A1 when the discharge lamp is not lit (the peak is fo) to the resonance curve A2 after the discharge lamp dielectric breakdown. Therefore, when the switching frequency of the first and second switching elements Q1 and Q2 is changed to a lower one, the resonance curve A after the discharge lamp La is broken down.
2 makes it possible to obtain more energy suitable for arcing since its switching frequency approaches the peak of the resonance frequency (fo ') at 2,
The discharge lamp La can be more stably shifted to arc discharge.

FIG. 6 is an explanatory diagram of a frequency sweep in the discharge lamp lighting device according to the third embodiment of the present invention. The first and second switching elements Q1 in at least one of the start-up periods TM11 and TM12 are shown. , Q2 by changing the switching frequency a plurality of times to apply a high voltage to the discharge lamp La. In this case, the control circuit 5C for the polarity reversing circuit, as shown in FIG.
11 and TM12, the switching element Q
1. Control is performed to change (sweep) the switching frequency f _{HF of} Q2 a plurality of times, for example, three times as shown in the figure. At this time, the sweep range of the switching frequency is set to include the peak of LC resonance by the inductor L1 and the capacitor C1 of the load resonance circuit 2A.

The first and second switching elements Q
1, the on-duty of Q2 may be swept together with the switching frequency sweep in the same manner as in the first embodiment, or may be changed to another constant value only when the switching frequency is swept. .

Next, the operation of the control circuit 5C, which is a feature of the third embodiment, will be briefly described. First,
The circuit operation in the control mode for the steady state will be described. During the lighting period TM21, the first switching element Q1 is kept off while the second switching element Q2 is kept off.
Is turned on / off by a high-frequency operation, while control for turning on / off the second switching element Q2 by a high-frequency operation while the first switching element Q1 is kept off during the period TM22 is repeated. The rectangular wave low-frequency voltage Vla is applied to the electric lamp La, a rectangular wave low-frequency current Ila flows, and the discharge lamp La is lit in a steady state.

Next, the circuit operation in the control mode for starting lighting will be described.
Is controlled so that both switching elements Q1 and Q2 are alternately turned on / off by a high-frequency operation so as to alternately generate a period TM12 in which the ON period of the first switching element Q1 is longer than the period TM12 and a period TM11 in which the ON period of the first switching element Q1 is shorter. As a result, a rectangular wave-like low-frequency voltage is applied to the discharge lamp La, and the DC component included in the lamp voltage Vla sufficiently supplies the discharge lamp La with energy necessary for shifting to arc discharge.

At this time, as shown in FIG. 6, the switching frequency of the first and second switching elements Q1 and Q2 is set to f1 in each of the periods TM11 and TM12.
The control is performed to change the frequency from 1 to f12 a plurality of times, whereby the L by the inductor L1 and the capacitor C1 of the load resonance circuit 2A is changed for each switching frequency sweep.
When the C resonance reaches a peak, a high-voltage pulse voltage that becomes a maximum is superimposed on the lamp voltage Vla, so that the discharge lamp La is suitably started and lit after dielectric breakdown. Also, by sweeping the switching frequency,
It becomes possible to apply a high-voltage pulse voltage, which is maximized even when the component constants vary, to the discharge lamp La.

As described above, according to the third embodiment, the same effects as those of the first embodiment can be obtained, and the discharge lamp La is more suitably started and turned on than in the first embodiment. It becomes possible to do. Further, if the output of the transmitter for generating the rectangular wave voltage in the control mode for the steady state is used for the generation timing of the frequency sweep operation, the circuit can be easily configured.

FIG. 7 is an explanatory diagram of a frequency sweep by a control circuit for a polarity reversing circuit of a discharge lamp lighting device according to a fourth embodiment of the present invention. In this case, the discharge lamp lighting device includes a DC power supply circuit, a load resonance circuit, a polarity inversion circuit, a control circuit for the DC power supply circuit, and a control circuit for the polarity inversion circuit, similarly to the third embodiment. The difference from the third embodiment is that the control circuit 5D for the polarity inversion circuit includes a Vla detection circuit, an Ila detection circuit, and a drive circuit. As shown in FIG.
, The first and second switching elements Q1,
A control circuit 5D that operates in the same manner as the control circuit 5C of the third embodiment except that the control of changing the duty to a smaller constant value is performed for each sweep of the switching frequency of Q2.
It has.

Here, the reason for changing the duty as described above will be explained. Since the discharge lamp La is a high-intensity discharge lamp, a high voltage is first applied to the discharge lamp La to start the discharge lamp. It is desirable to supply a sufficient amount of electric power at the time when the arc discharge occurs to shift the discharge to a stable state.

In order to further increase the high voltage during the switching frequency sweep period, it is necessary to make the duty closer to 0.5. As the duty becomes closer to 0.5, the voltage applied to the discharge lamp La increases. On the contrary, the DC component included in the applied voltage decreases. Thus, DC
If the arc discharge occurs in a state where the components are reduced, electric power sufficient to shift the discharge to a stable state is not supplied to the discharge lamp La, and in some cases, the discharge lamp La goes out.

Therefore, during the switching frequency sweep period, the duty is reduced so as to be close to 0.5 so that a higher high-voltage pulse voltage is applied to the discharge lamp La, and outside the sweep period, the duty is reduced. 0.5
The discharge lamp La is supplied with a sufficient amount of electric power to make the discharge lamp La have a stable discharge state.

As described above, according to the fourth embodiment, the same effects as those of the first embodiment can be obtained.

FIGS. 8, 9 and 10 show the fifth and fifth embodiments of the present invention, respectively.
Embodiments 6 and 7 will be described. The discharge lamp lighting device according to the fifth embodiment shown in FIG. 8 includes a booster 81 (AC / DC converter) that converts AC power of an AC power supply AC into a predetermined DC voltage,
Stabilizes the output of the booster as power to be supplied to the discharge lamp,
Step-down unit 82 for appropriately controlling the lighting voltage and current of the discharge lamp
(DC / DC converter) and an inverter that converts the DC output of the step-down unit 82 into a low-frequency rectangular wave and applies it to the discharge lamp, and generates a high-frequency high voltage including a DC component when the discharge lamp is started. And a starting circuit 83 (DC / AC converter).

The device according to the sixth embodiment shown in FIG. 9 converts the AC power of the AC power supply AC to DC, stabilizes the power supplied to the discharge lamp, and appropriately controls the lighting voltage and current of the discharge lamp. A power control unit 91 (AC / DC converter) that converts the DC output of the power control unit 91 into a low-frequency rectangular wave and supplies the low-frequency rectangular wave to the discharge lamp. Inverter and starting circuit 9 that generates voltage
2 (DC / AC converter).

The device according to the seventh embodiment shown in FIG. 10 includes a booster 101 (AC / DC converter) for converting the AC power of an AC power supply AC into a predetermined DC voltage, and a discharge lamp for outputting the output voltage of the booster. To stabilize the power supplied to the discharge lamp, properly control the lighting voltage and current of the discharge lamp, convert the booster output to a low-frequency rectangular wave applied to the discharge lamp, It comprises a power control / inverter / start circuit 102 (DC / AC converter) for generating a high voltage.

In each of the fifth to seventh embodiments, the AC power supply AC and the boosting units 81 and 101 may be replaced with DC power supplies, and the boosting unit and the power control unit 91 may control the input current from the AC power supply AC. It may have a function of suppressing an increase in distortion and keeping a high power factor. In addition, the inverter / starting circuits 83 and 92 and the power control / inverter / starting circuit 102
Are each provided with a resonance circuit comprising a series connection of at least a pair of inductors and a capacitor, and a discharge lamp La is connected to both ends of the capacitor.

In the operation of each device of the fifth to seventh embodiments, when the discharge lamp is started, the lighting operation is performed while changing the frequency at a high frequency near the resonance frequency of the resonance circuit. As a result, even if the resonance frequency changes due to variations in the inductor and capacitor of the resonance circuit,
Since the lighting operation is performed while changing the frequency, it is possible to reliably generate a resonance voltage for starting,
Further, since the circuit operation is not fixed at the resonance frequency, the generation period of the large resonance current flowing when the resonance voltage is generated is shortened, and the stress applied to each component can be reduced.

The inverter / starting circuit 83 and the power control / inverter / starting circuit 102 operate so as to superimpose a DC component on the high voltage due to the resonance at the time of starting. For example, by making the duty of the switching element operating at a high frequency in a bridge type inverter unbalanced, a DC component corresponding to the duty ratio is generated at both ends of the capacitor, and the DC component is superimposed at both ends of the discharge lamp. Voltage is generated. Accordingly, after the discharge lamp is broken down by the resonance voltage and starts, the transition from the glow discharge to the arc discharge is facilitated by the DC component, and the startability of the discharge lamp is improved.

In each of the embodiments described above, the polarity inversion circuit and the switching element of the inverter circuit are shown in a half-bridge configuration. However, in the present invention, the inverter may be in a full-bridge configuration.

In the eighth embodiment shown in FIG. 11, a polarity inversion circuit 113A including an inverter circuit having a switching element in a full-bridge configuration is used. The circuit 113A is connected to the output terminal of the DC power supply circuit 111A by, for example, a MOSFE.
T, a series circuit of first and second switching elements Q1 and Q2, and third and fourth switching elements Q3 and Q4.
Are connected to the connection point of the first and second switching elements Q1 and Q2 and the third and fourth switching elements Q
3, a series circuit of a capacitor C0 and an inductor L0 is connected to the connection point of Q4, and a high-intensity discharge lamp La is connected in parallel to the capacitor C0. A control circuit 115A for the polarity inversion circuit detects a lamp current. A circuit 114, a lamp voltage detection circuit 113, a control circuit 115, and a drive circuit 116 are provided.

When the discharge lamp La is not loaded,
The switching elements Q1 to Q4 are alternately turned on / off at a relatively high frequency as shown by waveforms Q1 to Q4 in FIG. 12 by a drive signal output from the drive circuit 116 in response to a signal from the control circuit 115. At this time, by setting the on / off frequency near the series resonance frequency of the inductor L0 and the capacitor C0, a high voltage Vla shown in FIG. 12 is generated at both ends of the capacitor C0.
The discharge lamp La is caused to break down by la and is started. When the no-load state is continued, the above-described no-load operation is performed intermittently.

Next, when the discharge lamp La is started and enters a steady state, the period in which the first and third switching elements Q1 and Q3 are switched at a high frequency is alternately repeated at a relatively low frequency. While Q1 is switching at a high frequency, the fourth switching element Q4
However, while the third switching element Q3 is switching at a high frequency, the second switching element Q2 is turned on. As a result, a lamp current Ila in which a high-frequency ripple component is superimposed on a direct-current component flows in the discharge lamp La in each polarity, and is alternated at a low frequency. It is lit.

The switching circuit Q1 to Q4 is supplied to the discharge lamp La by the control circuit 115 in accordance with signals from the lamp voltage detection circuit 113 and the lamp current detection circuit 114.
Is controlled, the appropriate output is supplied.

Here, in the eighth embodiment, similarly to the above-described embodiments, the discharge lamp La causes dielectric breakdown, and after the discharge lamp La starts, the discharge lamp La shifts to a steady state during the unstable period of the discharge.
A large amount of the lamp current Ila flows to facilitate the transition to arc discharge, and the startability is improved. The operation after the start is the same as that in each of the above-described embodiments, and thus the description is omitted.

On the other hand, in the ninth embodiment shown in FIG.
Third and fourth switching elements Q3, Q4 in the full bridge configuration of the switching elements of the first inverter circuit.
Are replaced by series-connected capacitors C01 and C02, and the LC resonance circuit further includes a series-connected inductor L1.
And a capacitor C2 at both ends of the capacitor C1, a capacitor C2 at both ends of the inductor L1 and the capacitor C1, and an inductor between a connection point of the inductor L1 and the capacitor C2 and a connection point of the first and second switching elements Q1 and Q2. L2 is inserted to form a double LC resonance circuit.

When a high-intensity discharge lamp is used as the discharge lamp La, high-frequency lighting of several tens of kHz is not normally performed unlike a fluorescent lamp. This is because in such a high frequency region, an acoustic resonance phenomenon may occur and the discharge may become unstable.
Therefore, in the case of a high-intensity discharge lamp, a low-frequency rectangular wave voltage,
Lighting by electric current is performed. However, also in this case, as in the above-described embodiment, a high-frequency component is superimposed on the lamp current by high-frequency switching of the first or second switching element at the time of steady lighting. An acoustic resonance phenomenon may occur. Therefore, in the ninth embodiment, a low-pass filter for removing this high frequency component is constituted by the inductor L2 and the capacitor C2 forming a double resonance circuit, and the high frequency component is removed to prevent the occurrence of an acoustic resonance phenomenon. Becomes possible.

In each of the embodiments described above, the control of the power supplied to the discharge lamp is performed by the inverter circuit portion of the polarity inversion circuit. However, as in the tenth embodiment shown in FIG. The inverter circuit portion may be separated. In this case, the power control portion is configured as a step-down chopper circuit, and the lamp power detection circuit 53 sets an appropriate lamp power value based on the detection values of the lamp voltage detection means 51 and the lamp current detection means 52, and the driving circuit 54 controls the operation of each of the switching elements Q1 to Q4 in the inverter section. The output obtained in this way is converted into a low-frequency rectangular wave in the inverter circuit portion and applied to the discharge lamp La. Each of the switching elements Q1 to Q4 in the inverter circuit portion operates as shown in the waveform diagram of FIG. 15, and generates a resonance voltage in which a DC component is superimposed as in the above-described embodiments. Is started.

In each of the above embodiments, the switching between the start and the lighting is not particularly specified, but the lighting of the discharge lamp is detected by the lamp current detecting means or the lamp voltage detecting means, whereby the operation of the discharge lamp is performed. The switching operation is performed, or after the start operation is continued for a certain period after the power is turned on, the operation can be switched to perform the lighting operation.

FIG. 16 is a waveform chart for explaining the operation of the eleventh embodiment in which the control circuit is configured to increase the lamp current immediately after the discharge lamp is started and to improve the startability in the first embodiment. FIG. FIG. 16A shows a no-load intermittent operation state (I) in which a no-load resonance voltage is intermittently applied to the discharge lamp La in a no-load state, and a steady operation state (II).
In the no-load intermittent operation state (I), FIG.
6 (b) and 16 (c), the switching element Q
1 and Q2 are controlled so that the operation of switching at a high frequency is intermittent, and the voltage is high as shown by the voltage 16 (d) applied to both ends of the discharge lamp La at that time. .

At this time, the control circuit 5A sets the indicated value of the lamp current Ila flowing through the discharge lamp La to a current value I1 larger than the current value I2 flowing during normal lighting as shown in FIG. When the discharge lamp La is started by causing a dielectric breakdown due to the resonance voltage when no load is applied, energy is supplied to the discharge lamp La from the DC power supply circuit 1A through the inverter circuit section of the polarity inversion circuit 3A, and FIG. As shown, the lamp current Ila starts to flow. Lamp current detection circuit 52
Detects the start of the flow of the lamp current Ila and detects the start of the discharge lamp La. That is, the lamp current detection circuit 5
Reference numeral 2 also serves as a lighting determination unit.

When the lamp current detection circuit 52 detects the start, a detection signal is output as shown in FIG. 16 (g), and the control circuit 5A receives the detection signal and receives the detection signal for a certain period of time τ. The switching elements Q1 and Q2 are connected so that a current having a current value I2 larger than the normal current value I1 determined by the detection signal from the lamp voltage detection circuit 51 flows.
The switching operation of Q2 is controlled. As a result, the discharge lamp La causes dielectric breakdown, and after starting, a large amount of the lamp current Ila can flow during the unstable period of the discharge, which shifts to the steady state, and the transition to the arc discharge becomes easy, and the startability is improved. Improvement can be achieved.

After the predetermined period τ has passed, the control circuit 5A
Controls the switching operation of the switching elements Q1 and Q2 so that the current value I1 determined by the detection signals from the lamp current detection circuit 52 and the lamp voltage detection circuit 51 flows.

FIG. 17 is a waveform chart showing the operation of the twelfth embodiment. The device of this embodiment has a means for intermittently applying a starting voltage in addition to the circuit configuration of the first embodiment. At the same time, the control circuit 5A stops the intermittent starting voltage applying means immediately after starting the discharge lamp, and continues starting the discharge lamp.

Now, in the operation process (I) in the no-load state shown in FIG. 17 (a), the discharge lamp La breaks down at a high voltage due to the no-load resonance voltage shown in FIG. 17 (d). Assuming that the lamp has started, the discharge lamp La has a DC power supply circuit 1A.
More energy is supplied and the lamp current Ila
The flow starts as shown in FIG. Lamp current detection circuit 5
1 detects the start of the flow of the lamp current Ila and detects the start of the discharge lamp La, and outputs a detection signal shown in FIG. 17 (g). Upon receiving the detection signal, the control circuit 5A switches the switching element Q1 for a certain period of time. , Q2, as shown in FIGS. 17 (b) and 17 (c), the switching operation is the same as that at the time of no load, and the intermittent operation at the time of no load is stopped to make the operation continuous. After a certain period of time τ, the control shifts to a steady operation.

As a result, the transition from the unstable state immediately after the start of the discharge lamp La to the arc discharge, which is a stable lighting state, is facilitated, and the operation process of the stable lighting state (III)
After the transition to the state, the switching to the steady state switching is performed, so that the starting can be surely performed. Moreover, the intermittent operation is stopped after the discharge lamp La has been broken down, and the operation is continued, so that the discharge lamp La can be prevented from being extinguished due to the intermittent oscillation operation, and the startability can be improved. FIG.
(E) shows the value of the lamp current Ila instructed by the control circuit 5A.

By the way, after the dielectric breakdown, in the process (II) of the no-load continuous operation, the discharge lamp La should go out,
The lamp current Ila stops flowing as shown by “a” in FIG. 18F, and the detection signal of the lamp detection circuit 51 is
Even if the output is stopped as shown in (g), due to the continuous continuation of the no-load operation, both ends of the discharge lamp La are located at both ends of FIG.
Since a high voltage due to the resonance voltage is applied as shown in
The dielectric breakdown occurs again, so that the discharge lamp La can be started, and a reliable start can be ensured. FIGS. 18 (a) to 18 (g) show timing charts corresponding to FIGS. 17 (a) to 17 (g).

FIG. 19 is a waveform diagram showing the operation of the thirteenth embodiment. The device of the present embodiment has an intermittent starting voltage applying means as in the twelfth embodiment, and the control circuit 5A operates in the same manner as the twelfth embodiment. Immediately after that, the intermittent starting voltage applying means is stopped, the starting of the discharge lamp is continued, and the lamp current is increased.

Now, in the operation process (I) in the no-load state shown in FIG. 19A, the discharge lamp La causes dielectric breakdown at the high voltage Vla due to the no-load resonance voltage shown in FIG. 19D. , The discharge lamp La is supplied with energy from the DC power supply circuit 1A, and the lamp current Ila starts to flow as shown in FIG. When the lamp current detection circuit 52 detects the start of the flow of the lamp current Ila and detects the start of the discharge lamp La, it outputs a detection signal shown in FIG. 19 (g). During the period τ, the switching operation of the switching elements Q1 and Q2 is set to the same switching operation as at the time of no load as shown in FIGS. 19B and 19C, and the intermittent operation at the time of no load is stopped to make the operation continuous. The control is performed, and the value of the lamp current Ila at this time is changed to a lamp current detection circuit 52 and a lamp voltage detection circuit 51 as shown in FIG.
From the current value I2 determined by the signal from
The switching of the switching elements Q1 and Q2 is controlled such that the current flows. After a certain period of time τ, the control shifts to a steady operation.

As a result, the transition from the unstable state immediately after the start of the discharge lamp La to the arc discharge, which is a stable lighting state, is facilitated, and the operation process of the stable lighting state (III)
After the transition to the state, the switching to the steady state switching is performed, so that the starting can be surely performed. Moreover, the intermittent operation is stopped after the discharge lamp La has been broken down, and the operation is continued, so that the discharge lamp La can be prevented from being extinguished due to the intermittent oscillation operation, and the startability can be improved.

FIG. 20 is a waveform diagram showing the operation of the device according to the fourteenth embodiment. This device has substantially the same configuration as the circuit according to the thirteenth embodiment, and the control circuit 5A operates intermittently immediately after starting. The operation of the discharge lamp is continued by stopping the voltage applying means and the lamp current is increased.
This is different from the third embodiment.

Now, in the operation process (I) in the no-load state shown in FIG. 20A, the discharge lamp La causes dielectric breakdown at a high voltage due to the no-load resonance voltage shown in FIG.
Assuming that the lamp has started, the discharge lamp La has a DC power supply circuit 1A.
From the lamp current Ila shown in FIG.
The flow starts as shown in FIG. Lamp current detection circuit 5
2 detects the start of the lamp current Ila and detects the start of the discharge lamp La, and outputs a detection signal shown in FIG. 20 (g). As shown in FIGS. 20B and 20C, the switching operation of the switching elements Q1 and Q2 is controlled to be the same as the operation at the time of no load, and to stop the intermittent operation at the time of no load to make the operation continuous. At the same time, the value of the lamp current Ila at this time is set so that a current having a value I1 larger than the current value I2 determined by the detection signals from the lamp current detection circuit 52 and the lamp voltage detection circuit 51 flows as shown in FIG. The switching of the switching elements Q1 and Q2 is controlled. Then, after a certain period of time τ has passed without extinction, the control shifts to a steady operation.

By the way, after the dielectric breakdown, in the no-load continuous operation process (II), the discharge lamp La goes out, and
(F) Even if the lamp current Ila stops flowing and the detection signal is no longer output from the lamp current detection circuit 52 as indicated by "a" in FIG. A high voltage due to the resonance voltage is generated at both ends of the electric lamp La as shown in FIG. 20D, and the discharge lamp La is restarted. Here, in the present embodiment, the continuous operation of the no-load operation is repeated for a certain period of time τ again from the time when the discharge lamp La is started again, thereby extending the no-load continuous operation process (III).

This facilitates the transition from the unstable state immediately after the start of the discharge lamp La to the arc discharge, which is a stable lighting state, and shifts to the steady-state switching state after the stable lighting state. As a result, reliable starting is possible. Moreover, the intermittent operation is stopped after the discharge lamp La has been broken down, and the operation is continued, so that the discharge lamp La can be prevented from being extinguished due to the intermittent oscillation operation, and the startability can be improved.

In the starting process, the discharge lamp L
Even when a disappears, a voltage for starting can be applied immediately, and the state shifts to a stable lighting state even after restarting, so that starting can be performed more reliably.

The discharge lamp lighting device according to the present invention is not limited to the above-described device, and it goes without saying that various changes can be made without departing from the spirit of the present invention.

[0083]

As described above, according to the discharge lamp lighting apparatus according to the present invention, the discharge lamp is suitably started and lit by the high-voltage pulse obtained by the LC resonance, and the arc discharge is smoothly performed. The energy supply required for the transition to the discharge lamp is supplied to the discharge lamp to improve the startability, and at the same time, it is possible to reduce the cost of components such as coils, capacitors, switching elements, etc. Play.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram of the discharge lamp lighting device according to the first embodiment of the present invention.

FIG. 3 is a signal waveform diagram of each part of the discharge lamp lighting device according to the first embodiment of the present invention at the time of starting and at the time of lighting.

FIG. 4 is an explanatory diagram of a switching frequency sweep direction in the discharge lamp lighting device according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of a switching frequency sweep direction in a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram of a frequency sweep by a control circuit for a polarity inversion circuit in a discharge lamp lighting device according to a third embodiment of the present invention.

FIG. 7 is an explanatory diagram of a frequency sweep by a control circuit for a polarity inversion circuit in a discharge lamp lighting device according to a fourth embodiment of the present invention.

FIG. 8 is a schematic block diagram of a discharge lamp lighting device according to a fifth embodiment of the present invention.

FIG. 9 is a schematic block diagram of a discharge lamp lighting device according to a sixth embodiment of the present invention.

FIG. 10 is a schematic block diagram of a discharge lamp lighting device according to a seventh embodiment of the present invention.

FIG. 11 is a circuit diagram of a discharge lamp lighting device according to an eighth embodiment of the present invention.

FIG. 12 is a signal waveform of each part in a discharge lamp lighting device according to an eighth embodiment of the present invention.

FIG. 13 is a circuit diagram of a discharge lamp lighting device according to a ninth embodiment of the present invention.

FIG. 14 is a circuit diagram of a discharge lamp lighting device according to a tenth embodiment of the present invention.

FIG. 15 is a signal waveform of each part of the discharge lamp lighting device according to the tenth embodiment of the present invention.

FIG. 16 is a signal waveform of each part of the discharge lamp lighting device according to the eleventh embodiment of the present invention.

FIG. 17 is a timing chart for explaining the operation of the discharge lamp lighting device according to the twelfth embodiment of the present invention.

FIG. 18 is a timing chart for explaining the operation of the discharge lamp lighting device according to the thirteenth embodiment of the present invention.

FIG. 19 is a timing chart for explaining the operation of the discharge lamp lighting device according to the fourteenth embodiment of the present invention.

FIG. 20 is a timing chart for explaining the operation of the discharge lamp spot lighting device according to the fifteenth embodiment of the present invention.

[Explanation of symbols]

 1A DC power supply 2A Load resonance circuit 3A Polarity inversion circuit 4A Control circuit 5A Control circuit 11A Boost chopper circuit L1 Inductor C1 Capacitor La Discharge lamp

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsutomu Shiomi 1048, Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. (72) Inventor San Eyan Beverly Holly Lane 26, Mass., USA Takeshi Kenshi, Kazuma, Kazuma, Osaka 1048 Matsushita Electric Works, Ltd. (72) Inventor Hiroshi Niibori, 1048 Kazuma, Kazuma, Osaka, Matsushita Electric Works F-term (reference) 3K072 AA11 BA05 BB10 BC01 DD03 DD04 EA07 EB05 EB07 GA03 GB12 GB18 GC04 HA05 HA06 HA10

Claims (23)

[Claims] 1. A direct-current power supply circuit having a pair of output terminals for supplying direct-current power, and at least first and second switching elements connected in series with an output terminal of the direct-current power supply circuit, wherein the first and second switching elements are connected in parallel. A polarity inversion circuit for converting DC power into AC power, a load resonance circuit comprising an inductor, a capacitor, and a discharge lamp, to which AC power is supplied from the polarity inversion circuit, and first and second switching elements of the polarity inversion circuit And a control unit for alternately turning on / off a voltage applied to the discharge lamp of the load resonance circuit, the control unit comprising: a first period in which an on period of the second switching element is longer than that of the first switching element; The first and second switching elements are alternately turned on / off at a high frequency so as to alternately generate a shortened second period, and a rectangular wave low frequency is applied to the discharge lamp. In addition to applying pressure, a DC component is superimposed on the resonance pulse from the load resonance circuit in the starting and lighting modes of the discharge lamp, and the switching frequency of each switching element is continuously changed to apply a high voltage to the discharge lamp. Lighting device. 2. The discharge lamp lighting device according to claim 1, wherein the control means changes the switching frequency of the first and second switching elements at a predetermined time from the start of at least one of the first and second periods. 3. The discharge lamp lighting device according to claim 1, wherein the control means changes the switching frequency of the first and second switching elements a plurality of times in at least one of the first and second periods. 4. The discharge lamp lighting device according to claim 1, wherein the control means changes the switching frequency of the first and second switching elements in at least one of the first and second periods to one of a low frequency and a high frequency. . 5. The discharge lamp lighting device according to claim 2, wherein the control unit changes the switching frequency of the first and second switching elements in at least one of the first and second periods to one of a low frequency and a high frequency. . 6. The discharge lamp lighting device according to claim 1, wherein the control means changes the switching frequency of the first and second switching elements in at least one of the first and second periods to a lower frequency. 7. The discharge lamp lighting device according to claim 2, wherein the control means changes the switching frequency of the first and second switching elements in at least one of the first and second periods to a lower frequency. 8. The polarity inverting circuit further includes first and second capacitors connected in series with the first and second switching elements, and the first and second switching elements are half-bridge connected. The discharge lamp lighting device as described in the above. 9. The polarity inverting circuit further includes third and fourth switching elements connected in series with the first and second switching elements, and the first to fourth switching elements are full-bridge connections. 2. The discharge lamp lighting device according to 1. 10. The series resonance circuit according to claim 1, wherein the inductor and the capacitor of the load resonance circuit are connected in series.
The discharge lamp lighting device as described in the above. 11. The load resonance circuit is a double LC resonance circuit including two inductors and two capacitors.
The discharge lamp lighting device as described in the above. 12. The polarity reversing circuit includes first and second capacitors connected in series and connected in parallel with the first and second switching elements, and the load resonance circuit includes a connection point between the first and second switching elements and the first capacitor. , A series-connected first inductor and a third capacitor connected between the connection point of the second capacitor, a fourth capacitor connected in parallel to the first inductor and the third capacitor, and a first and a second switching element. 2. A discharge circuit according to claim 1, comprising a double LC resonance circuit comprising a second inductor inserted between the connection point and the connection point between the first inductor and the fourth capacitor, and a discharge lamp connected in parallel to the third capacitor. Lighting device. 13. The polarity reversing circuit includes first and second capacitors connected in series and connected in parallel with the first and second switching elements, the first and second switching elements are half-bridge connected, and the control circuit is 2. The discharge lamp lighting device according to claim 1, wherein the switching frequency of the first and second switching in at least one of the first and second periods is changed. 14. The DC power supply circuit according to claim 1, wherein the DC power supply circuit includes means for converting AC power from the AC power supply into DC power, and the replacement means has a configuration using first and second switching elements of a polarity inversion circuit. Discharge lamp lighting device. 15. The discharge lamp of the load resonance circuit is a high-intensity discharge lamp, the polarity inversion circuit includes intermittent oscillation means for intermittently performing a high-frequency switching operation of the first and second switching elements, and the control circuit has a high-frequency discharge operation. The control circuit includes at least an intermittent oscillating means of the polarity inversion circuit for a predetermined period after the lighting determination means determines the lighting state of the high-intensity discharge lamp. The discharge lamp lighting device according to claim 1, wherein stable lighting of the electric lamp is achieved. 16. The control circuit according to claim 15, wherein the lighting determination means maintains the lighting at a current value larger than a predetermined current value flowing through the high-intensity discharge lamp during the initial lighting for a predetermined period after the lighting determination of the high-intensity discharge lamp. The discharge lamp lighting device as described in the above. 17. The discharge lamp according to claim 15, wherein the control circuit maintains the lighting of the high-intensity discharge lamp in a state where the load resonance circuit is operated for a predetermined period after the lighting determination means determines the lighting of the high-intensity discharge lamp. Lighting device. 18. A control circuit for prohibiting the operation of the intermittent oscillating means even if the lighting determination means determines a failure of the high-intensity discharge lamp in a predetermined period after the lighting determination of the high-intensity discharge lamp, The discharge lamp lighting device according to claim 15, wherein the operation of applying a voltage to the high-intensity discharge lamp is continued, and the starting operation of the load resonance circuit is maintained. 19. A control circuit for prohibiting the operation of the intermittent oscillating means even if the lighting determining means determines that the high-intensity discharge lamp is not defective during a predetermined period after the lighting determining means determines that the high-intensity discharge lamp is lit. The start operation of the load resonance circuit is continued while the voltage applying operation to the high-intensity discharge lamp is continued, and a current having a value larger than a predetermined current value supplied to the high-intensity discharge lamp at the time of initial lighting is supplied to the high-intensity discharge lamp The discharge lamp lighting device according to claim 15, which is supplied to the discharge lamp. 20. A control circuit further comprising a lamp current detecting means and a lamp voltage detecting means, wherein a DC power supply circuit is provided when the high-intensity discharge lamp starts due to dielectric breakdown caused by the resonance voltage of the load resonance circuit when there is no load. The current flowing from the lamp current detection means is detected by the lamp current detection means, and in response to the detection signal, the control circuit continues the operation of the first and second switching elements of the polarity inversion circuit for a certain period and stops the operation of the intermittent oscillation means. The operation of the first and second switching elements is performed such that the starting operation is continued and the lamp current value at this time is larger than a current value determined by each detection signal from the lamp current detecting means and the lamp voltage detecting means. The discharge lamp lighting device according to claim 15, which controls the following. 21. A DC power supply circuit comprising: a rectifier connected in parallel to an AC power supply; a boost chopper circuit connected in parallel to the rectifier; and a second inductor and an anode connected at one end to a high potential output terminal of the rectifier. A first diode connected to the other end of the inductor, a third switching element connected to the other end of the second inductor and the low-potential output terminal of the rectifier, and a parasitic diode connected in parallel to the third switching element. The polarity inversion circuit includes a series connection of a second diode, a first switching element, a third diode, and a second switching element connected in parallel to an output of the DC power supply circuit, and a connection of the second diode and the first switching element in parallel. A fifth diode connected in parallel with the fourth diode, the third diode, and the second switching element, and a fifth diode connected in parallel with the output of the DC power supply circuit. , The third capacitor is connected in series, and the load resonance circuit is connected between the connection point of the first switching element of the polarity inversion circuit and the third diode, the connection point of the fourth and fifth diodes, and the connection point of the second and third capacitors. A discharge lamp connected in series between a first inductor and a first capacitor connected in parallel between the first inductor and the first capacitor;
A first control circuit for increasing the output voltage of the rectifier to a predetermined level by on / off control of a switching element, and first and second switching based on a discharge lamp power obtained by detecting a current and a voltage supplied to the discharge lamp. 2. The discharge lamp lighting device according to claim 1, further comprising a second control circuit for controlling on / off of the element. 22. A DC power supply circuit comprising: a rectifier connected in parallel to an AC power supply; a second capacitor connected in parallel to an output terminal of the rectifier; a second inductor having one end connected to a high-potential output terminal of the rectifier; A first diode connected to the other end of the inductor, a third switching element connected to the other end of the second inductor and the low potential output terminal of the rectifier, and a cathode of the first diode connected to the low potential output terminal of the rectifier The polarity inversion circuit is a full bridge circuit including a series connection of the first and second switching elements and a series connection of the fourth and fifth switching elements connected in parallel to the output terminal of the DC power supply circuit. The load resonance circuit includes a first inductor and a first capacitor connected between a connection point of the first and second switching elements and a connection point of the fourth and fifth switching elements of the polarity inversion circuit. The control means is supplied to the discharge lamp and a first control circuit for controlling ON / OFF of the third switching element according to the output of the DC power supply circuit. 2. The discharge lamp lighting device according to claim 1, further comprising a second control circuit for detecting current and voltage and controlling on / off of the first, second, fourth, and fifth switching elements according to the detection signals. . 23. The polarity reversing circuit further includes a series connection of a second capacitor and a third capacitor connected in parallel to an output terminal of the DC power supply circuit, and the load resonance circuit includes the series connection of the inductor and the capacitor. A first resonance circuit having one end on the capacitor side connected to a connection point between the second capacitor and the third capacitor, and the other end on the inductor side connected to a connection point between the first and second switching elements; And the second resonance circuit, which is a series connection of a third inductor connected between the other end of the first resonance circuit on the inductor side and the connection point of the first and second switching elements. The discharge lamp lighting device according to claim 1, wherein the load is connected to both ends of a capacitor of the first resonance circuit.