JP2007141752A - Step-up transformer, discharge lamp lighting circuit, discharge lamp device, and discharge lamp lighting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce costs and save space by dispensing with components having high-breakdown voltages, reducing insulation distance to feedback in a space saving manner, and preventing a transformer from becoming large. <P>SOLUTION: A step-up transformer T1 divides secondary-side winding S1 into high-voltage winding S1H for obtaining high-voltage output and detection winding S1L for obtaining low-voltage output and obtains low-voltage output for detecting abnormalities by a low voltage generated in the detection winding S1L. A discharge lamp lighting circuit inputs oscillation output from an oscillation circuit 1 to primary-side winding P1 in the step-up transformer T1, and outputs high-voltage output from the high-voltage winding S1H in the secondary-side winding S1 in the transformer. When lighting a discharge lamp Z1 by the high-voltage output of the transformer T1, a control circuit 2 controls an oscillation circuit 1 by the low-voltage output for detecting abnormalities from the detection winding S1L in the secondary-side winding S1 in the transformer T1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-pressure transformer, a discharge lamp lighting circuit, a discharge lamp device, and a discharge lamp lighting method, and more particularly to a high-pressure transformer, a discharge lamp lighting circuit, a discharge lamp device, and a discharge lamp lighting method that prevent abnormal operation of the discharge lamp.

  Generally, a discharge lamp is lit by a high voltage supplied from a discharge lamp lighting circuit. Here, what connected the discharge lamp to the discharge lamp lighting circuit is called a discharge lamp device. A discharge lamp in which a rare gas is sealed has different lamp lighting voltages and discharge start voltages due to different types of discharge lamps, lamp lengths, and the like. Therefore, the output voltage of the discharge lamp lighting circuit varies depending on the discharge lamp.

  For example, in a cold cathode lamp used for a liquid crystal backlight or the like, the lamp voltage of a small monitor lamp is about 500V, and the lighting start voltage is about 800V. Further, the lamp voltage of the large TV lamp is about 1500V, and the lighting start voltage is about 2000V.

  In a general discharge lamp lighting circuit, an output having an oscillation frequency of several tens of KHz to several hundred KHz is boosted by a step-up transformer and supplied to the discharge lamp to light the discharge lamp. A method for detecting the abnormality of the discharge lamp lighting circuit or the abnormality of the lighting circuit high-voltage portion will be described with reference to the circuit diagrams of the conventional example 1 shown in FIGS. In FIG. 3, the discharge lamp lighting circuit includes an oscillation circuit 1, a control circuit 2, and a step-up transformer T1a. The input voltage Vin to the oscillation circuit 1 is supplied from the input connector 3, and the output voltage is supplied from the output connector 4 to the discharge lamp Z1.

  As the oscillation circuit 1, there are a self-excited circuit and a separately excited circuit. In addition, a pulse circuit or the like may be considered depending on the lamp and lighting efficiency. The control circuit 2 is a circuit that triggers the detected voltage when an abnormal waveform is detected and stops the oscillation circuit 1 or intermittently oscillates to perform a protective operation.

  When the input voltage Vin is supplied to the oscillation circuit 1, the oscillation circuit 1 oscillates and the oscillation output of the oscillation circuit 1 is supplied to the primary winding of the step-up transformer T1a. From the secondary winding of the step-up transformer T1a, a boosted output boosted according to the winding ratio is obtained. This boosted output is supplied from the output connector 12 to the discharge lamp Z1, and turns on the discharge lamp Z1.

  In this case, the abnormality of the high voltage section is detected by a voltage dividing circuit of capacitors C1 and C2 connected in series to the secondary winding of the step-up transformer T1a as shown in FIG. The high voltage of the step-up transformer T1a is divided by the capacitance ratio of the capacitors C1 and C2, and this divided output is fed back to the discharge control circuit 2. When the discharge control circuit 2 detects an abnormality with this divided voltage output, the oscillation circuit 1 is controlled to operate protection circuits such as stop of discharge, reduction of discharge voltage, and intermittent operation. Since these capacitors C1 and C2 are used in a high voltage circuit, they need to be high voltage capacitors.

  The circuit shown in FIG. 4 is almost the same as FIG. 3, but detection of an abnormality in the high voltage section is detected by a voltage dividing circuit of resistors R1 and R2 connected in series to the secondary winding of the step-up transformer T1a. The point to do is different. This circuit also feeds back the divided voltage divided by the resistors R1 and R2 to the discharge control circuit 2 to detect an abnormality, and operates a protection circuit such as stop of discharge or reduction of the discharge voltage, intermittent operation. Since these resistors R1 and R2 are also used in a high voltage circuit, they need to be high withstand voltage resistors.

  In general, a discharge lamp lighting circuit is used as a light source lighting circuit for office automation equipment such as lighting, liquid crystal backlights, and scanners. In such applications, the safety of the equipment is required, and a wide variety of protection circuits are required. In particular, high voltage may occur, and there is a risk of electric shock if there is an abnormality in the discharge lamp, an abnormality in the high voltage section after the step-up transformer, or an abnormality in the connector harness that connects the lighting circuit to the discharge lamp. Most devices are equipped with a high voltage protection circuit. High-voltage components used in conventional protection circuits are expensive and have a problem that it is difficult to ensure an insulation distance because of high voltage.

  As another conventional discharge lamp lighting device, there is a circuit (conventional example 2) described in Patent Document 1. The circuit of this discharge lamp lighting device is shown in the block diagram of FIG. In this discharge lamp lighting device, the commercial power supply AC is connected to the rectifier circuit 11, and the rectified output of the rectifier circuit 11 is converted into an arbitrary DC output by the DC power supply circuit 12. The inverter circuit 13 oscillates at an arbitrary frequency according to a signal from the inverter control circuit 14, converts the DC output of the DC power supply circuit 12 into AC and outputs the AC to the load circuit 15.

  The load circuit 15 includes a series resonance circuit of an inductance L1 and a capacitor C11, a series circuit of a primary winding N1 of a step-up transformer T2 and a capacitor C12 connected in parallel to the capacitor C11, and a secondary winding N2 of the step-up transformer T2. And the discharge lamp Z2 and a tertiary winding N3 of the step-up transformer T2. The load circuit 15 supplied with the AC output of the inverter circuit 13 generates a high voltage at both ends of the capacitor C11 due to the resonance action of the inductance L1 and the capacitor C11. As a result, a high voltage induced in the secondary winding N2 from the primary winding N1 of the step-up transformer T2 is applied to the discharge lamp Z2, and the discharge lamp Z2 starts lighting.

  After the discharge lamp Z2 is turned on, the inverter control circuit 14 controls the oscillation operation of the inverter circuit 13 to a predetermined oscillation frequency, whereby an arbitrary discharge lamp output can be obtained.

  The capacitor C12 is a direct current cut capacitor when the discharge lamp Z2 is lit, and the tertiary winding N3 of the step-up transformer T2 is a lamp voltage of the discharge lamp Z2 detected for performing an operation for determining an output abnormality of the discharge lamp Z2. Is output to the abnormality detection circuit 16 of the discharge lamp as a detection signal Vla.

  The abnormality detection circuit 16 determines whether the discharge lamp Z2 is normal or not based on the detection signal Vla, and outputs the determination result to the inverter control circuit 14. The inverter control circuit 14 oscillates the inverter circuit 13 based on the determination result. To control.

  When the discharge lamp Z2 is normally lit, the inverter control circuit 14 controls the oscillation frequency of the inverter circuit 13 so that the discharge lamp output becomes a predetermined value.

  At the end of the life of the discharge lamp Z2, the emitter applied to the filament is consumed, and the discharge lamp Z2 becomes an abnormal discharge that performs a rectifying action in which current flows only in one direction. Hereinafter, this phenomenon is called Emiles. At this time, the resonance system collapses, and the lamp voltage of the discharge lamp Z2 rises abnormally compared to that during normal discharge. In addition, when the discharge lamp Z2 is in a lighting operation, even when an abnormality such as an outgassing (slow leak) of the discharge lamp Z2 occurs and the discharge lamp Z2 is extinguished, the resonance under no load is similarly performed. It suddenly changes to a curve and rises abnormally.

  Next, in the abnormality detection circuit 16, the detection signal Vla obtained from the tertiary winding N3 of the step-up transformer T2 is smoothed and input to the comparator as a DC detection voltage Va. The comparator compares the threshold voltage Vr1 output from the DC voltage source with the detection voltage Va. When the threshold voltage Vr1 is higher, an L level signal is output to the inverter control circuit 14, and when the detection voltage Va is higher, an H level signal is output to the inverter control circuit 14.

  Here, when the discharge lamp Z2 is normally lit, the lamp voltage is lower and the voltage level of the detection signal Vla is lower than that at the time of abnormality. As a result, the detection voltage Va is also low, the detection voltage Va becomes lower than the threshold voltage Vr1, and the comparator outputs an L level signal to the inverter control circuit 14. The inverter control circuit 1 controls the oscillation operation of the inverter circuit 13 to a predetermined oscillation frequency so as to obtain an arbitrary discharge lamp output while the L level signal is input.

  When the lamp voltage of the discharge lamp Z2 rises due to the discharge lamp abnormality, the voltage level of the detection signal Vla also rises as compared with it. As a result, the detection voltage Va also rises, and when the detection voltage Va becomes larger than the threshold voltage Vr1, the comparator outputs an H level signal to the inverter control circuit 14. Then, when the H level signal is input, the inverter control circuit 14 determines that the discharge lamp is abnormal, and shifts the oscillation operation of the inverter circuit 13 to the protection operation. Here, the protection operation is any operation among stopping the oscillation operation, intermittently performing the oscillation operation, and performing a weak resonance effect by considerably increasing the oscillation frequency.

  In the conventional example 2, when the lamp voltage of the discharge lamp Z2 becomes equal to or higher than the threshold voltage when the discharge lamp is abnormal, the threshold value of the DC voltage source E1 is determined so that the inverter control circuit 14 determines that the discharge lamp is abnormal. By setting the value of the voltage Vr1 and the constant of each part of the abnormality detection circuit 16, the normality / abnormality determination of the discharge lamp Z2 is performed. The tertiary winding N3 of the step-up transformer T2 outputs the lamp voltage of the discharge lamp Z2 detected for performing the output abnormality determination operation of the discharge lamp Z2 to the abnormality detection circuit 16 as the detection signal Vla.

JP 2002-299084 A (FIG. 1)

  However, the above-described discharge lamp lighting circuit according to Conventional Example 1 has a problem that the cost of high-voltage components used in the protection circuit is high and it is difficult to secure an insulation distance because of the high voltage. .

  Further, in the discharge lamp lighting circuit of the conventional example 2, there is a problem in that the number of secondary windings of the step-up transformer T2 is two windings of the second winding and the third winding. That is, the step-up transformer T2 is provided with a third winding separately from the second winding for detecting an abnormality, and detects an abnormality from the voltage induced in the third winding. In this case, the abnormality is detected in the third winding. To use the third winding for detecting the abnormality, the coupling between the third winding and the second winding must be strengthened. Cannot be detected. When the coupling between the third winding and the second winding is strengthened, a measure for insulating the second winding from the third winding is required. For example, as a countermeasure, an insulating sheet and an insulating distance are taken, which is a demerit that leads to an increase in the size of the step-up transformer.

  The object of the present invention is to simplify the detection of abnormalities, do not require high-voltage components, reduce the insulation distance to feedback, save the transformer size, and keep the transformer size unchanged. Another object is to provide a discharge lamp device and a discharge lamp lighting method.

  The structure of the present invention is a step-up transformer having a high-voltage winding for obtaining a high-voltage output in the secondary-side winding, and having a detection winding for dividing the secondary-side winding to obtain a low-voltage output. The abnormality detection is performed by the low pressure output.

  According to another aspect of the present invention, in the step-up transformer having a high-voltage winding that inputs an oscillation voltage of a predetermined frequency to the primary-side winding and obtains a high-voltage output from the secondary-side winding on the output side, the secondary-side winding is It has a detection winding that divides and obtains a low-voltage output, and abnormality detection is performed by the low-voltage output of this detection winding.

  In the present invention, the number of detected windings of the secondary side winding can be set to one-tenth to one hundredth of the number of high-voltage windings of the secondary side winding. The output of the high-voltage winding of the secondary winding can be several hundred volts to several thousand volts, and the output of the detection winding can be several tens of volts or less.

  Another configuration of the present invention includes a step-up transformer that inputs an oscillation output of an oscillation circuit to a primary side winding and outputs a high-voltage output from a high-voltage winding of the secondary side winding, and the secondary side of the step-up transformer In the discharge lamp lighting circuit that controls the oscillation circuit so as to suppress the abnormality of the high-pressure circuit by the control circuit, the step-up transformer divides the secondary side winding. A detection winding for obtaining a low-voltage output, and detecting an abnormality by the low-voltage output of the detection winding, and the control circuit controlling the oscillation circuit by a low-voltage output for abnormality detection of the detection winding. It is characterized by.

  In the present invention, the control circuit stops the oscillating operation of the oscillating circuit, intermittently performs the oscillating operation, lowers the oscillating operation level, or raises the oscillating frequency to perform a weak resonance action. In addition, the high-voltage circuit can be a circuit formed by a transformer secondary-side component including the step-up transformer, a discharge lamp, or an output connector and a harness.

  The configuration of the discharge lamp device according to the present invention is characterized in that a discharge lamp is connected to a high-pressure output of a step-up transformer in the above-described discharge lamp lighting circuit to light the discharge lamp.

  In still another configuration of the present invention, a predetermined oscillation output of the oscillation circuit is input to the primary winding of the step-up transformer, and the discharge lamp is turned on by a high-voltage output from the high-voltage winding of the secondary winding of the step-up transformer. In the discharge lamp lighting method for controlling the oscillation circuit so as to suppress the abnormality of the high-voltage circuit by the control circuit, the step-up transformer is for detecting an abnormality from the detection winding that divides the secondary side winding to obtain a low-voltage output. In addition to obtaining an output, the control circuit controls the oscillation circuit with an abnormality detection low-voltage output from the detection winding.

  In the present invention, the control circuit stops the oscillating operation of the oscillating circuit, intermittently performs the oscillating operation, lowers the oscillating operation level, or raises the oscillating frequency to perform a weak resonance action. Can be controlled.

  As described above, according to the present invention, the abnormality detection circuit is simplified, and there is an effect that a high voltage component is not required. In addition, the effect of low cost and space saving can be expected.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a discharge lamp lighting circuit according to an embodiment of the present invention, and FIG. 2 is a wiring diagram illustrating a step-up transformer used in FIG.

  In the present embodiment, as shown in FIG. 2, the step-up transformer T1 has a secondary winding S1 with respect to the input primary winding P1, and the entire secondary winding S1 is divided. The high-voltage winding S1H for obtaining a high-voltage output and the detection winding S1L for obtaining a low-voltage output are provided. And abnormality detection is performed by the low voltage | pressure output voltage which generate | occur | produces in this detection coil | winding S1L.

  Further, the discharge lamp lighting circuit of the present embodiment is a circuit for lighting the discharge lamp Z1 using the high voltage output of the step-up transformer T1. The discharge lamp device of the present embodiment is characterized in that the discharge lamp Z1 is lit by connecting the discharge lamp Z1 to the high-pressure output of the discharge lamp lighting circuit.

  The discharge lamp lighting circuit includes a step-up transformer T1, an oscillation circuit 1 that outputs an oscillation output of a predetermined frequency to a high-voltage output of the step-up transformer T1, a control circuit 2 that detects an abnormality in the high-voltage circuit and controls the oscillation circuit 1. Is provided. This discharge lamp lighting circuit lights the discharge lamp Z1 by the high voltage output of the step-up transformer T1. The control circuit 2 controls the oscillation circuit 1 by detecting an abnormality by a low voltage output from the detection output terminal of the detection winding S1L of the step-up transformer T1. The oscillation circuit 1 is supplied with power from the input connector 3. Further, the high voltage output of the step-up transformer T1 is supplied from the output connector 4 to the discharge lamp Z1, and the discharge lamp Z1 is turned on.

  The high-voltage circuit is a circuit formed by a transformer secondary side component including the step-up transformer T1, the discharge lamp Z1, or the output connector 4, and a harness, and an abnormal voltage of these circuits is detected from a detection output terminal that is the detection winding S1L. Is done.

  As shown in FIG. 1, the discharge lamp lighting circuit feeds back to the control circuit 2 a voltage generated in the detection winding S1L that divides the secondary winding of the step-up transformer T1 to obtain a low-voltage output. The control circuit 2 detects an abnormality in the high voltage circuit and controls the oscillation circuit 1. The control circuit 2 performs control by stopping the oscillation operation of the oscillation circuit 1, performing the oscillation operation intermittently, reducing the oscillation operation level, or increasing the oscillation frequency to perform a weak resonance action. By this control, it becomes possible to stop the discharge of the discharge lamp Z1 or to lower the discharge voltage, and to perform a protection circuit operation such as an intermittent operation.

  As described above, according to the present embodiment, the secondary winding that detects the induced voltage is unnecessary (two secondary windings are unnecessary) as in the conventional example 2, and the secondary winding directly connected to the discharge lamp load is used. Since the detection output is obtained by dividing the windings, it is possible to detect an abnormality with a simple configuration in which the secondary winding S1L is connected to an empty pin of the step-up transformer. Therefore, the size of the step-up transformer does not change.

  In addition, according to the present embodiment, 1) the abnormality detection circuit is simplified, 2) high voltage components are not required, and 3) the withstand voltage distance (space / creeping distance) is not high because the feedback to the control circuit is not high voltage. There is an effect of saving space (reducing the substrate size).

  The first embodiment of the present invention has the same configuration as that shown in FIGS. As shown in FIG. 1, the discharge lamp lighting circuit includes an oscillation circuit 1, a control circuit 2, a step-up transformer T1, and a discharge lamp Z1. In the first embodiment, when the abnormality of the discharge lamp Z1, the abnormality of the high voltage section after the step-up transformer T1, the abnormality of the connector harness connecting the lighting circuit and the discharge lamp, the secondary voltage of the step-up transformer T1 is normal. Therefore, the abnormality can be detected by the secondary voltage of the step-up transformer T1.

  In this embodiment, since the detection winding S1L divides and outputs the high voltage output of the secondary winding of the step-up transformer T1, the fact that the voltage generated in the detection winding S1L is different from that during normal operation is used. To detect anomalies. The voltage generated in the detection winding S1L is fed back to the control circuit 2. For this reason, the turns ratio of the high-voltage winding S1H and the detection winding S1L of the secondary winding of the step-up transformer T1 in FIG. 2 is divided into several hundreds: 1 to several tens: 1. By setting such a winding ratio, the high voltage of several hundred volts to several thousand volts of the high voltage winding S1H of the secondary winding is changed to a low detection voltage of several tens of volts or less of the detection winding S1L. Can be reduced. Therefore, it is not necessary to use a high voltage component that can withstand high voltage in the circuit of the detection winding S1L.

  The operation of this discharge lamp lighting circuit is as follows. When steady power is input from the connector 3 to the oscillation circuit 1 of the discharge lamp lighting circuit, an oscillation signal is output from the oscillation circuit 1 to the step-up transformer T1. The step-up transformer T1 outputs a voltage proportional to the turn ratio between the primary winding and the secondary winding to the secondary winding side. In this discharge lamp lighting circuit, as shown in FIG. 2, since the secondary winding is divided, the discharge voltage necessary for lighting the discharge lamp Z1 is generated on the high-voltage winding S1H side of the secondary winding. Yes.

  Further, when there is an abnormality in the discharge lamp Z1, an abnormality in the high voltage section after the step-up transformer, or an abnormality in the connector / harness connecting the lighting circuit and the discharge lamp, the secondary voltage of the step-up transformer T1 is different from the secondary voltage in the steady state. It will be. Therefore, it is possible to identify whether or not the step-up transformer T1 is a steady secondary voltage by feeding back the voltage generated in the detection winding S1L of the secondary winding to the control circuit 2.

  At this time, the number of turns of the detection winding S1L is set to one tenth to one hundredth of the number of turns of the high-voltage winding S1H. Therefore, it is not necessary to use a high voltage component for the feedback stage of the control circuit 2, and a cost merit can be obtained.

  As the oscillation circuit 1, a self-excited circuit (for example, a Royer circuit) or a separately excited circuit (for example, a half bridge circuit) can be used. In addition, a pulse circuit or the like may be considered depending on the lamp and lighting efficiency. In addition, when an abnormal waveform (such as a sine wave or a pulse voltage) is detected, the control circuit 2 triggers the detected voltage to stop the oscillation circuit 1 or intermittently oscillate to suppress the abnormality and perform a protective operation. Circuit. For example, there is a circuit that stops the oscillation by comparing the detected voltage of the step-up transformer T1 with a comparator or the like and shutting down the voltage of the oscillation circuit 1 when the voltage is abnormal.

  As another embodiment of the present invention, the secondary winding of the step-up transformer T1 may not be divided into two. For example, it is possible to divide into three or four according to the boost ratio of the boost transformer T1 and the number of transpins. Of these divided windings, a winding that obtains a necessary high voltage output and a low voltage output of an optimum level as an abnormality detection level may be used.

It is a block diagram explaining the discharge lamp lighting circuit containing the high voltage | pressure transformer of the 1st Embodiment of this invention. FIG. 2 is a wiring diagram of a high-voltage transformer part in FIG. 1. It is a block diagram explaining the discharge lamp lighting circuit of a prior art example. It is a block diagram explaining the other discharge lamp lighting circuit of a prior art example. It is a block diagram explaining the high voltage | pressure transformer of another conventional example, and a discharge lamp lighting circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Oscillation circuit 2 Control circuit 3 Input connector 4 Output connector 11 Rectifier circuit 12 DC power supply circuit 13 Inverter circuit 14 Inverter control circuit 15 Load circuit 16 Abnormality detection circuit C1, C2, C11, C12 Capacitor L1 Inductance R1, R2 Resistance T1, T1a , T2 Step-up transformer Z1, Z2 Discharge lamp

Claims (10)

A step-up transformer having a high-voltage winding that obtains a high-voltage output in the secondary-side winding has a detection winding that divides the secondary-side winding to obtain a low-voltage output, and an abnormality is detected by the low-voltage output of this detection winding A step-up transformer characterized in that In a step-up transformer having a high-voltage winding that inputs an oscillation voltage of a predetermined frequency into a primary-side winding and obtains a high-voltage output from the output-side secondary-side winding, the secondary-side winding is divided to obtain a low-voltage output A step-up transformer having a detection winding and detecting abnormality by a low-voltage output of the detection winding. The step-up transformer according to claim 1 or 2, wherein the number of detected windings of the secondary side winding is one tenth to one hundredth of the number of high voltage windings of the secondary side winding. The high-voltage transformer according to claim 3, wherein the output of the high-voltage winding of the secondary winding is several hundred volts to several thousand volts, and the output of the detection winding is several tens of volts or less. A step-up transformer that inputs the oscillation output of the oscillation circuit to the primary winding and outputs a high-voltage output from the high-voltage winding of the secondary winding, and the discharge lamp is driven by the high-voltage output of the secondary winding of the boost transformer In the discharge lamp lighting circuit that controls the oscillation circuit so as to suppress the abnormality of the high voltage circuit by the control circuit,
The step-up transformer has a detection winding that divides the secondary side winding to obtain a low-voltage output, performs abnormality detection by the low-voltage output of the detection winding, and the control circuit A discharge lamp lighting circuit, wherein the oscillation circuit is controlled by a low pressure output. The control circuit controls to stop the oscillation operation of the oscillation circuit, intermittently perform the oscillation operation, lower the oscillation operation level, or increase the oscillation frequency to perform a weak resonance action. Item 6. A discharge lamp lighting circuit according to Item 5. The discharge lamp lighting circuit according to claim 5 or 6, wherein the high-voltage circuit is a circuit including a transformer secondary side component including the step-up transformer, a discharge lamp, or an output connector and a harness. 8. The discharge lamp device according to claim 5, wherein a discharge lamp is connected to a high-voltage winding output of a step-up transformer in the discharge lamp lighting circuit to light the discharge lamp. The predetermined oscillation output of the oscillation circuit is input to the primary winding of the step-up transformer, the discharge lamp is turned on by the high-voltage output from the high-voltage winding of the secondary winding of the step-up transformer, and abnormalities in the high-voltage circuit are detected by the control circuit. In the discharge lamp lighting method for controlling the oscillation circuit to suppress,
The step-up transformer obtains an abnormality detection output from a detection winding that divides the secondary winding to obtain a low-voltage output, and the control circuit controls the oscillation circuit by the low-voltage output of the detection winding A discharge lamp lighting method characterized by the above. The control circuit controls to stop the oscillation operation of the oscillation circuit, intermittently perform the oscillation operation, lower the oscillation operation level, or increase the oscillation frequency to perform a weak resonance action. Item 10. A discharge lamp lighting method according to Item 9.

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