JP2006339098A - Discharge lamp lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of suppressing surge voltage generated at the start of a discharge lamp even if an output cable connecting a discharge lamp and a bootstrap circuit becomes long. <P>SOLUTION: This discharge lamp lighting device provided with a main body case 1 housing a ballast circuit 15 and a bootstrap circuit 12 and an output cable comprising an H side output line 20a and an L side output line 20b connected with a starting transformer 12, has a first magnetic-material member 21 covering the H side output line 20a, a second magnetic-material member 22 covering the L side output line 20b and a third magnetic-material member 23 covering both the H side output line 20a and the L side output line 20b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a discharge lamp lighting device which is connected to a discharge lamp and outputs a high voltage pulse for starting and an alternating voltage for lighting to the discharge lamp, and particularly for reducing noise generated at the time of starting the discharge lamp. Concerning configuration.

  A discharge lamp lighting device that is mounted on an automobile or the like and lights a discharge lamp such as an HID (High Intensity Discharge) lamp generally boosts the DC voltage output from the battery 101 as shown in FIG. A DC / DC converter 102, a DC / AC inverter 103 that converts the boosted DC voltage into an AC voltage, a starting transformer 105, and a trigger circuit 106, and a high voltage pulse is applied to the HID lamp 100 when the HID lamp 100 is started. Is provided (see, for example, Patent Document 1).

  In the circuit configuration shown in FIG. 5A, the output voltage (12 V or 24 V) of the battery 101 is boosted to a DC high voltage of about 400 V by the DC / DC converter 102, and the DC high voltage is converted into the DC / AC inverter 103. Is converted into an AC voltage of several hundred Hz and supplied to the HID lamp 100. And the HID lamp 100 is maintained in the lighting state by the AC voltage.

  Further, the output of the DC / AC inverter 103 is set to AC or DC of several hundred volts when the HID lamp 100 is turned off. When the HID lamp 100 is started, the primary voltage for starting pulse generation is applied to the secondary winding of the starting transformer 105 by applying the starting voltage generating primary voltage from the trigger circuit 106 to the primary winding of the starting transformer 105. A high voltage corresponding to the turn ratio with the next winding is generated, and the HID lamp 100 is started (lights on) by applying the high voltage.

  FIG. 5B shows an attachment mode when the main body case 110 containing the circuit configuration of FIG. 5A described above is connected to the base 114 of the HID lamp via the output cable 120 in the headlamp unit of the automobile. As shown in the figure, the main body case 110 is generally attached to the lower part of the housing 130 of the headlamp unit. A lens 111 is mounted on the front surface of the housing 130, and a maintenance cover 112 is provided on the rear surface of the housing 130.

  In the housing 130, a projector lamp 113 using an HID lamp as a light source, a lamp socket 115 mounted on a base 114 of the HID lamp, and an ASF (Adaptive Front) that rotates the projector lamp 113 to change its irradiation direction. -lighting System) A motor drive circuit 122 and a motor / gear unit 121 for realizing the function are provided.

  Here, as a form of the discharge lamp lighting device, as shown in FIGS. 6A to 6C, three types are roughly adopted. In the first embodiment shown in FIG. 6A, all circuit configurations (the startup circuit 126 and the ballast circuit 125 including a DC / DC converter, a DC / AC inverter, etc.) are accommodated in one main body case 110. The lamp socket 115 is connected to the main body case 110 by the output cable 120 and is fitted to the base 114 of the HID lamp 100.

  Further, in the second embodiment shown in FIG. 6B, the starting circuit 126 is separated and accommodated in the starting circuit case 110b, the ballast circuit 125 is accommodated in the main body case 110a, and the first output cable 120a is used. The starting circuit case 110b and the main body case 110a are connected, and the starting circuit case 126 is connected to the lamp socket 115 by the second output cable 120b.

  In the third mode shown in FIG. 6C, the starting circuit 126 is separated and accommodated in the lamp socket 115a, and the main body case 110a is connected to the lamp socket 115a by the output cable 120.

  When the discharge lamp lighting device of the first embodiment shown in FIG. 6 (a) and the third embodiment shown in FIG. 6 (c) is mounted on a headlamp unit, the main body cases 110 and 110a are housings of the headlamp unit. The base 114 of the HID lamp 100 is fitted into the lamp sockets 115 and 115a.

  Further, when the discharge lamp lighting device of the second form shown in FIG. 6B is attached to the headlamp unit, the main body case 110a is attached to the housing of the headlamp unit in the same manner as the first and third forms. The lamp socket 115a is fitted to the base of the HID lamp 100 by attaching to the lower part. And it is necessary to fix the starting circuit case 110b inside the housing 130 such as the inside of the maintenance cover 112 shown in FIG. 5B.

  Here, in the headlamp unit having the AFS function as shown in FIG. 6B, the motor drive unit 122 and the motor / gear unit 121 are arranged in the housing 130, so the housing 130 is enlarged. Further, the housing 130 may be enlarged due to the design shape of the headlamp.

  When the housing of the headlamp is thus increased in size, in the discharge lamp lighting device of the first embodiment, the output cable 120 that connects the main body case 110 attached to the lower portion of the housing and the lamp socket 115 becomes longer. Become. Also in the discharge lamp lighting device of the second embodiment, the output cable 120b for connecting the starting circuit case 110b fixed in the housing and the lamp socket 115 becomes long depending on the installation location of the starting circuit case 110b. As the output cables 120a and 120b are lengthened, the level of the impulsive surge voltage generated when a high voltage is output from the starting circuit 126 when the HID lamp 100 is started increases, and the ballast circuit 125 is caused by the input of the surge voltage. There is a risk of damage.

  Further, when the AFS function is provided, in the discharge lamp lighting device of the second embodiment, since the motor drive circuit 122 and the motor gear unit 121 are provided, the space in the housing of the headlamp unit is reduced. When the second form shown in (b) is adopted, there is an inconvenience that it becomes difficult to accommodate the startup circuit case 110b.

  Further, in the discharge lamp lighting device of the third embodiment shown in FIG. 6C, since the starting circuit 126 is built in the lamp socket 115a, the generation of a surge voltage at the start of the HID lamp 100 is suppressed. However, the lamp socket 115a increases in weight. Therefore, referring to FIG. 5B, there is a disadvantage that the load on the motor / gear unit 121 and the motor driving circuit 122 that rotate the lamp socket 115 connected to the projector lamp 113 together with the projector lamp 113 is increased.

Furthermore, in an in-vehicle electronic device, measures are taken to prevent the generation of radiation noise that adversely affects other devices such as audio, but the ballast circuit 125 accommodated in the main body cases 110 and 110a is also used. Shielding measures are taken to generate strong noise. As a countermeasure against the shield, generally, the output cables 120, 120a, and 120b are covered with a shield material knitted with a metal wire, and a metal cover that covers the lamp sockets 115 and 115a itself is attached. If the output cables 120, 120a, 120b are longer, the necessary shielding material also becomes longer, resulting in an increase in cost.
JP 11-329768 A

  The present invention has been made in view of the above background, and a discharge lamp capable of suppressing a surge voltage generated at the start of the discharge lamp even when the output cable connecting the starter circuit and the discharge lamp becomes long. An object is to provide a lighting device.

  The present invention has been made to achieve the above object, and is connected to a discharge lamp via an output cable composed of a first output line and a second output line, and at the time of starting the discharge lamp, a DC voltage or an AC voltage is provided. And an inverter circuit that outputs an AC voltage after starting the discharge lamp, and a starter transformer having a secondary winding connected between the inverter circuit and the first output line, In a discharge lamp lighting device comprising a starting circuit for generating a starting pulse in a DC voltage or an AC voltage output from the inverter circuit when starting the discharge lamp, a first magnetic member that covers the first output line It is provided with.

  According to the present invention, as will be described in detail later, when a high voltage pulse is output from the start-up transformer when starting the discharge lamp, a surge current flows through the first output line and the first output line A magnetic field is generated around At this time, the first magnetic member covering the first output line acts to absorb and reduce high-frequency power from the magnetic flux generated by the magnetic field generated around the first output line. To do. Therefore, the surge current at the start of the discharge lamp, which tends to increase as the output cable becomes longer, can be reduced, and the inverter circuit can be prevented from being damaged by the surge voltage generated by the surge current. Further, due to the reduction of the surge current, radiation noise generated from the first output line and the second output line when the discharge lamp is turned on is also reduced. Therefore, there is no need to shield the first output line and the second output line, and when the first output line and the second output line are lengthened, the necessary amount of the shielding member is accordingly accompanied. There is no increase in cost due to an increase in.

  In addition, the first magnetic body member has a 10 MHz band (10 MHz or more) than an impedance in a low frequency region up to 1 MHz band (1 MHz or more and less than 10 MHz) with respect to an AC voltage superimposed on the output cable. , Frequency characteristics in which the impedance is higher in a high frequency region from a frequency region of less than 100 MHz to a 100 MHz band (a frequency region of 100 MHz or more and less than 1000 MHz).

  According to the present invention, the high frequency noise included in the TV band (about 90 MHz to 770 MHz) is avoided while avoiding the influence on the high voltage output in the low frequency region output from the starting transformer when the discharge lamp is started. By blocking signal components in the high frequency region from the 10 MHz band to the 100 MHz band, it is possible to suppress the generation of radiation noise that adversely affects other electronic devices.

  In addition, at least one of a second magnetic member that covers the second output line and a third magnetic member that covers both the first output line and the second output line is provided. It is characterized by that.

  According to the present invention, by providing the second magnetic member, radiation noise generated from the second output line can be further reduced. Further, by providing the third magnetic member, it is possible to further reduce common mode radiation noise generated from the first output line and the second output line.

  Further, the second magnetic body and the third magnetic body have an impedance in a high frequency region of 10 MHz band to 100 MHz band rather than an impedance in a low frequency region up to 1 MHz band with respect to an alternating current flowing through the output cable. It has the characteristic that the frequency characteristic becomes higher.

  According to the present invention, it is possible to avoid the influence on the high voltage output in the low frequency region output from the start-up transformer when starting the discharge lamp, and the high frequency from the 10 MHz band to the 100 MHz band, which is the high frequency noise of the TV band. By blocking signal components in the region, it is possible to suppress the generation of radiation noise that adversely affects other electronic devices.

  Embodiments of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a discharge lamp lighting device according to the present invention, FIG. 2 is an explanatory diagram of a surge voltage generated at the start of an HID lamp, and FIG. 3 is an explanatory diagram of an experimental circuit for confirming the effect of reducing inductive surge current. FIG. 4 is an explanatory diagram of high-frequency noise generated when the HID lamp is turned on.

  Referring to FIG. 1, the discharge lamp lighting device of the present embodiment is connected to HID lamp 30 (corresponding to the discharge lamp of the present invention) used for a vehicle headlight and the like, and lights HID lamp 30. A main body case 1 containing a circuit board, a lamp socket 31 into which the HID lamp 30 is detachably fitted, and an output cable 20 (20a, 20b) connecting the main body case 1 and the lamp socket 31. Composed.

The main body case 1 is a metal housing, the circuit board in the main body case 1, DC / DC converter 10 that generates a high DC voltage by boosting the DC voltage V _in supplied from the battery 35, the DC Start-up that has a DC / AC inverter 11 that converts a high voltage into an AC voltage, a start-up transformer 13 and a trigger circuit 14 and applies a high-voltage pulse to the HID lamp 30 when the HID lamp starts (when lighting starts) A circuit 12 is provided.

  The output line 20a on the High side of the output cable 20 connected to the starter transformer 13 (corresponding to the first output line of the present invention, hereinafter referred to as the H-side output line 20a) is connected to the H-side output line 20a. A first magnetic body member 21 is attached, and the output line 20b on the low side of the output cable 20 (corresponding to the second output line of the present invention, hereinafter referred to as the L-side output line 20b) is L. A second magnetic member 22 that covers the side output line 20b is attached.

  Further, the output cable 20 is provided with a third magnetic member 23 that covers both the H-side output line 20a and the L-side output line 20b. As the first magnetic member 21, the second magnetic member 22, and the third magnetic member 23, magnetic members such as a clamp type, a bead type, and a sleeve type can be used.

In the main body case 1, noise mainly due to the switching operation of the DC / DC converter 10 occurs. DC / DC converter 10, for boosting by switching the frequency of about several 10KHz~ number 100KHz DC voltage V _in supplied from the battery 35, generates a noise to consideration of several MHz harmonics. However, since the secondary winding of the starting transformer 13 acts as a sufficient filter inductor for the output voltage and output current, the propagation of noise from the main body case 1 to the outside is shielded.

  As described above, since the noise generated in the main body case 1 is shielded, the high frequency noise centering on the FM band to the TV band is limited to the HID lamp 30 outside the main body case 1 as a countermeasure. Can be applied. In addition, since the starting transformer 13 acts as a normal choke coil, it is desirable to arrange a common mode choke filter at the output section.

  Next, in the ballast circuit 15 including the DC / DC converter 10 and the DC / AC inverter 11, the failure rate is generally higher due to the voltage / current usage rate and transient fluctuations than for the low power use. Semiconductor elements are frequently used, and if an impulsive surge voltage generated when the HID lamp 30 is started enters the ballast circuit 15, the high-power semiconductor elements are easily damaged. The ballast circuit 15 is provided with a CMOS logic circuit that operates with a low voltage of about 5 V in order to control the operation of the high-power semiconductor device. However, the surge voltage intrusion may cause a latch-up failure of the CMOS logic circuit. It becomes a factor.

  FIG. 2A shows the generation mechanism of the impulsive surge voltage that causes the failure of the ballast circuit 15 as described above. The impulsive surge voltage generated when the HID lamp 30 is started is activated. This can be confirmed by the voltages Sa and Sb propagating from the circuit 12 through the filter circuit 45 to the H bridge circuit 40 of the DC / AC inverter.

  The H bridge circuit 40 outputs an alternating voltage by alternately switching between a state in which the FET 41 and the FET 44 are turned on and the FET 43 and the FET 42 are turned off, and a state in which the FET 41 and the FET 44 are turned off and the FET 43 and the FET 42 are turned on. The impulse surge voltage can be confirmed as a voltage between the drain and the source of the FET that is turned off.

  When the HID lamp 30 is started, the H bridge circuit 40 outputs a DC voltage while maintaining the state in which the FET 41 and the FET 44 are turned on and the FET 43 and the FET 42 are turned off, as shown in FIG. Then, a starting pulse is superimposed on this DC voltage by the starting circuit 12, and a high voltage pulse is applied to the HID lamp 30.

  In this way, the cause of the surge voltage when a high voltage pulse is applied to the HID lamp 30 is that the steep pulsed surge generated in the H-side output line 20a and the L-side output line 20b connected to the HID lamp 30. Current and wiring inductance.

  Regarding the surge voltage observed at the FETs 41 to 44 of the H-bridge circuit 40, the location where the H-side output line 20a is connected (x in the figure) and the location where the L-side output line 20b is connected (y in the diagram). It is observed similarly at two points. This is because even if the surge current Ic that causes the generation of the surge voltage is attenuated by the inductance of the secondary winding of the starting transformer 13 or the inter-winding capacitance in the H-side output line 20a, the H-side output line 20a and the L-side This is because the surge currents propagate while being electromagnetically induced between the output lines 20b, so that a similar surge voltage is generated.

  Regarding the generation process of the surge current in the H-side output line 20a and the electromagnetic induction to the L-side output line 20b, the pulse width of the generated surge voltage is in the high frequency range of 10 nsec to 20 nsec. This can be clarified by treating it as a high-frequency transmission line with parallel output lines.

  In order to start (lighting start) the HID lamp 30, a high voltage pulse of about 20 kV is applied. When this high voltage pulse is applied to the H-side output line 20a, the applied voltage is between the electrodes of the HID lamp 30. It rises at a certain rate of increase until the discharge starts. During this time, a strong electric field is formed around the H-side output line 20a due to the applied high voltage. A magnetic field Hb is generated according to the change in the strength of the electric field, and a pulse current Sc opposite to the pulse current Sd flowing through the H-side output line 20a is applied to the L-side output line 20b so as to cancel the magnetic field Hb. Will flow.

  As described above, a pulse current flows through the H-side output line 20a and the L-side output line 20b before the HID lamp 30 is started. This pulse current has a strong surge characteristic because of the high frequency in the H-side output line 20a. It is by synthesis. Since there is a line capacitance between the H-side output line 20a and the L-side output line 20b, and there is also an inductance of the wire, high-frequency parasitic vibration is generated in the pulse current Ia generated by the application of the high voltage pulse.

  The pulse current Ia oscillated in this way is the same as the reflected wave Ib reflected in the same phase because the end of the H-side output line 20a is opened by the electrode of the HID lamp 30 before the HID lamp 30 is started. Waveform synthesis is performed between them. In addition, the reflection current Ic of the pulse current Ic is also generated at the connection point with the starting transformer 13 on the opposite side because of the impedance change. As a result, in the H-side output line 20a between the starting transformer 13 and the HID lamp 30, reflection and transmission of the pulse current are repeated, and a high-frequency pulse current having irregular vibration is generated by combining these pulse currents. In the process of synthesizing the pulse current, if the peaks of the parasitic vibration pulses overlap, a pulse current with high surge characteristics is generated.

  Further, when the HID lamp 30 is started at the time when such a high surge current is generated, the terminal of the H-side output line 20a is short-circuited to the L-side output line 20b, and the pulses that have been synthesized in phase until then. Since the currents are synthesized in the reverse phase, the pulse current waveform is reversed at the start of the HID lamp 30 and becomes a surge pulse current having a rapid current change rate. Since the surge pulse current propagates while inducing the H-side output line 20a and the L-side output line 20b, a similar surge voltage is generated in the H-bridge circuit 40.

As described above, when the HID lamp 30 is started by applying a high voltage pulse, a pulse current with high surge characteristics (hereinafter referred to as a surge current) is generated before and after the HID lamp 30 is started. FIG. 2B shows an actual surge current waveform, where the vertical axis is set to current (I) and the horizontal axis is set to time (t). The application of high voltage pulses to the H side output line 20a at time t ₀ is started, there is shown a case of HID lamp 30 is started (start of lighting) in t _1, a large surge current before and after t ₁ It can be seen that

  Here, the surge current tends to increase as the H-side output line 20a becomes longer. This is because as the H-side output line 20a becomes longer, the inductance of the wire and the line capacity between the H-side output line 20a and the L-side output line 20b increase, and the amplitude of the parasitic vibration pulse increases. This is because a large surge current is synthesized. For example, when the H-side output line 20a and the L-side output line 20b are set to 20 cm, a stronger resonance action occurs and the surge current increases when the length is set to 40 cm.

  In addition, when a countermeasure for covering the output line with a metal film for shielding, which is generally performed as a countermeasure against radiation noise, is taken, an effect of increasing an impulsive surge current occurs. This is because if the output line is covered with a metal coating, a capacitor is formed between the output line and the metal coating in addition to the line capacitance, and the parasitic vibration is strengthened. In addition, the capacitor has a charge of charge of about 1 to 2 kV in which the starting pulse voltage is attenuated by the metal coating, and when the capacitor is discharged when the HID lamp 30 is started, an impulse surge current is generated. Increase the surge voltage further.

  As described above, the surge current that causes the surge voltage is combined in the H-side output line 20a, and further, the L-side output line 20b generates a surge current due to electromagnetic induction. By reducing the generation of surge current due to induction, generation of surge voltage can be suppressed.

  That is, an inductive surge generated before and after the HID lamp 30 is started by weakening the magnetic field generated around the H-side output line 20a after electric field radiation from the H-side output line 20a due to application of a high voltage pulse. The current can be reduced. The first magnetic member 21 shown in FIG. 1 absorbs magnetic flux generated by the magnetic field and weakens the magnetic field generated around the H-side output line 20a, thereby reducing inductive surge current. It is.

  As the frequency characteristic of the first magnetic member 21, it is preferable that the impedance is low at 10 MHz or less and high impedance is maintained in the range of several tens to several hundreds of MHz so that the power loss when the HID lamp 30 is turned on does not increase. . In consideration of being attached to the H-side output line 20a that outputs a high voltage of 20 kV, it is preferable that the insulation resistance is high. Further, considering the secular change, temperature characteristics, cost, etc., Ni-based ferrite is suitable as the material.

  Table (1) below shows the effect of reducing the surge voltage when a member using Ni-based ferrite is covered as the first magnetic member 21 on the H-side output line 20a.

  As apparent from Table (1) above, when the first magnetic member 21 is not mounted, when the output line (b) is made 40 cm longer than when the output line (a) is 20 cm. The surge voltage is higher. Then, as shown in (c), by mounting the first magnetic member 21, the level of the surge voltage when the output line is 40 cm can be greatly reduced.

  In order to investigate the effect of reducing the inductive surge current caused by mounting the first magnetic member 21 on the 40 cm long H-side output line 20a, the inventors of the present application use the circuit configuration shown in FIG. The experiment was conducted. In the circuit configuration shown in FIG. 3, a 10 kΩ chip resistor 50 rated at 62.5 mW is connected in parallel with the L-side output line 20 b, and the power supply generated by the surge current is set to be an overpower for the chip resistor 50. ing.

  The magnetic field generated around the H-side output line 20a is started 3000 times each when the first magnetic member 21 is not attached and when the first magnetic member 21 is attached. The overpower deterioration of the chip resistor 50 due to the surge current Se of the L-side output line 20b induced by Hc was confirmed. The results are shown in Table (2) below.

  In Table (2), the resistance value change when the first magnetic member 21 was mounted was 9.6 kΩ to 9.1 kΩ, whereas the resistance when the first magnetic member 21 was not mounted. The change in the value is 8.4 kΩ to 9.1 kΩ, and it can be seen that the degree of deterioration of the chip resistor 50 is large. Thus, it was confirmed that the effect of reducing the surge current Se generated in the L-side output line 20b can be obtained by mounting the first magnetic member 21. The reason why the resistance value of the chip resistor 50 varies is that there is a difference in the width of the resistor trimmed in the trimming process for aligning the resistance value.

  Next, the effect of reducing the discharge noise in the discharge lamp lighting device shown in FIG. 1 will be described with reference to FIG. As shown in FIGS. 4A and 4B, when the HID lamp 30 is lit by the AC voltage output from the DC / AC inverter 11, the discharge noise Da, Db, Dc, and Dd have different effects on the H-side output line 20a and the L-side output line 20b.

  As shown in FIG. 4A, when the AC side High-side Pg is supplied to the H-side output line 20a, the L-side output line 20b is directly connected to GND and has a relatively low impedance termination. ing. Therefore, the high frequency noises Nb and Na propagated to the L-side output line 20b due to the discharge noises Da and Db generated in the HID lamp 30 are easily absorbed and reduced by the GND.

  On the other hand, the H-side output line 20a is connected to the DC / AC inverter 11 (see FIG. 1) via the starting transformer 13, and the termination is high impedance. Therefore, the high-frequency noise Nc propagated to the H-side output line 20a is not easily absorbed, and a part of the high-frequency noise Nc is reflected by the starting transformer 13 to generate a reflected wave Nd.

  Further, as shown in FIG. 4B, when the high voltage side Pg of the AC voltage is supplied to the L side output line 20b, the L side output line 20b is directly connected to the output part of the DC / AC inverter 11. Thus, the termination is relatively low impedance. Therefore, the high frequency noises Ne and Nf propagated to the L-side output line 20b due to the discharge noises Dc and Dd generated in the HID lamp 30 are easily absorbed by the DC / AC inverter 11 and reduced.

  On the other hand, the H-side output line 20a is connected to GND via the activation transformer 13, and the termination is high impedance. Therefore, the high-frequency noise Ng propagated to the H-side output line 20a is not easily absorbed, and a part of the high-frequency noise Ng is reflected by the starting transformer 13 to generate a reflected wave Nh.

  The high frequency noise and the reflected wave are combined between the HID lamp 30 and the starting transformer 13 to generate a strong noise component. Further, when the application of the AC voltage to the HID lamp 30 is turned off by the counter electromotive force action due to the inductance of the secondary winding of the starting transformer 13, vibration is generated in the H-side output line 20a, which is also a component of high-frequency noise. It becomes. The induced current flows in the L-side output line 20b by the magnetic field generated by the high-frequency noise current generated in the H-side output line 20a in this way, but the L-side output line 20b has a low impedance as described above. Because it is terminated, the induced current is reduced.

  Thus, when the HID lamp 30 is turned on, the high frequency noise component is synthesized by the H-side output line 20a. Therefore, by attaching the first magnetic member 21 to the H-side output line 20a, the high-frequency noises Nc and Ng propagating to the H-side output line 20a are attenuated and the dielectric current generated in the L-side output line 20b is also reduced. Therefore, the generation of radiation noises Wa and Wb caused by noise components can be effectively reduced.

  As described above, by attaching the first magnetic member 21 to the H-side output line 20a, it is possible to suppress the generation of a surge voltage when the HID lamp 30 is started, and to turn on the HID lamp 30 constantly. Generation of radiation noise at the time can be reduced.

  Further, by attaching the second magnetic member 22 (see FIG. 1) to the L-side output line 20b, the induction current generated in the L-side output line 20b and the discharge noise generated near the HID lamp 30 are reduced. The generation of radiation noise can be further reduced. Further, by mounting the third magnetic member 23 (see FIG. 1) that covers both the H-side output line 20a and the L-side output line 20b, the common mode component of discharge noise generated near the HID lamp 30 is further reduced. Thus, the radiation noise can be further reduced.

  In this way, the first magnetic member 21 is mounted, and then the second magnetic member 22 and the third magnetic member 23 are mounted in combination, so that mercury that generates strong noise particularly at the time of starting. Even in a free HID lamp, discharge noise can be effectively reduced. The following table (3) shows the level (peak value) of radiation noise in the frequency band from 1 MHz to 1 GHz generated from the start of the HID lamp to the stable lighting state in a vehicle headlamp using a mercury-free HID lamp. ) In the case where noise countermeasures are taken by the first magnetic member 21, the second magnetic member 22, and the third magnetic member 23 of the present invention, and noise by the shield of the conventional output line and lamp socket The experimental results are shown in comparison between the case where measures are taken and the case where these measures against noise are not taken.

  From the experimental results in the above table (3), it can be seen that in the conventional noise countermeasure by the shield, the noise level is reduced by 10 dB on the rear side of the lamp, but the noise level in front of the lamp is not reduced. And it is fully considered that the radiation noise ahead of the lamp affects the host vehicle in consideration of the reflected wave. In addition, since radiation noise is generated over a wide range of high-frequency regions, there is a risk of adversely affecting commercial radio such as taxi radio.

  On the other hand, in the noise countermeasure by mounting the first to third magnetic members of the present invention, the noise level is reduced by 20 dB on the lamp rear side, and the noise level in front of the lamp is also reduced by 10 dB. This is because the mounting of the first magnetic member 21, the second magnetic member 22, and the third magnetic member 23 reduces the power of high-frequency conductive noise propagating through the output lines 20a and 20b. This is because the generation of radiation noise is suppressed.

  Thus, by providing the first magnetic member 21, the second magnetic member 22, and the third magnetic member 23, the radiation noise is reduced without performing the shielding process on the output lines 20a and 20b. be able to. Therefore, when the output lines 20a and 20b are lengthened, an increase in cost due to an increase in the necessary amount of the shield member does not occur.

  In the present embodiment, the first magnetic member 21, the second magnetic member 22, and the third magnetic member 23 are provided. However, the H-side output line 20a that easily generates a high level surge current. It is essential to attach the first magnetic body member 21 to the second magnetic body member 22 covering the L-side output line 20b, and the third magnetic member covering both the H-side output line 20a and the L-side output line 20b. About the body member 23, what is necessary is just to mount | wear suitably according to specifications, such as a vehicle with which a discharge lamp lighting device is mounted, and lighting equipment. In this case, an appropriate noise countermeasure can be taken by a simple method of mounting the second magnetic member 22 and the third magnetic member 23 without a large design change on the vehicle or lighting device side.

[The invention's effect]
According to the present invention, even if the H-side output line and the L-side output line are lengthened to some extent by providing the first magnetic member that covers the H-side output line, the surge voltage generated when starting the discharge lamp It is possible to prevent the circuit portion from being damaged.

  Therefore, unlike the embodiment of FIG. 6 (c) described in the background art, it is not necessary to separate the starting circuit 126 from the main body case 110a and provide it in the lamp socket 115a, and the AFS unit (motor) of FIG. A headlamp unit including a gear unit 121 and a motor drive circuit 122) can also be handled in the form of FIG.

  Moreover, since the first magnetic body member is provided, discharge noise generated at the time of starting or steady lighting of the discharge lamp is reduced, so that shielding measures for the H-side output line and the L-side output line are not required, and the cost can be reduced. Radiation noise countermeasures can be taken. In this case, it is also possible to reduce radiation noise in front of the discharge lamp, which was difficult with conventional noise countermeasures using a shield.

  Further, the second magnetic member covering the L-side output line, the H-side output line, and the L-side output line are both covered according to the allowable level of radiation noise in a vehicle, lighting fixture, or the like in which the discharge lamp lighting device is mounted. Generation of radiation noise can be further suppressed by a simple method of mounting the third magnetic body members in appropriate combinations.

The block diagram of the discharge lamp lighting device of this invention. Explanatory drawing of the surge voltage which arises at the time of starting of an HID lamp. Explanatory drawing of the experimental circuit for confirming the reduction effect of an inductive surge current. Explanatory drawing of the high frequency noise produced at the time of HID lamp lighting. The block diagram of the conventional discharge lamp lighting device, and explanatory drawing of the attachment aspect to a headlamp unit. Explanatory drawing of the structural aspect of the conventional discharge lamp lighting device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Main body case, 10 ... DC / DC converter, 11 ... DC / AC inverter, 12 ... Starting circuit, 13 ... Starting transformer, 14 ... Trigger circuit, 15 ... Ballast circuit, 20a ... H side output line (1st output Line), 20b ... L side output line (second output line), 21 ... first magnetic member, 22 ... second magnetic member, 23 ... third magnetic member, 30 ... HID lamp (release) Electric lamp), 31 ... lamp socket, 40 ... H bridge circuit, 45 ... filter circuit

Claims (4)

Connected to the discharge lamp through an output cable composed of a first output line and a second output line, outputs a DC voltage or an AC voltage when starting the discharge lamp, and outputs an AC voltage after starting the discharge lamp. An inverter circuit;
A starting transformer having a secondary winding connected between the inverter circuit and the first output line, and starting to a DC voltage or an AC voltage output from the inverter circuit when starting the discharge lamp In a discharge lamp lighting device comprising a starting circuit for generating a pulse,
A discharge lamp lighting device comprising a first magnetic member covering the first output line.   The first magnetic member has a frequency characteristic that an impedance in a high frequency region from 10 MHz band to 100 MHz band is higher than an impedance in a low frequency region up to 1 MHz band with respect to an alternating current flowing through the output cable. The discharge lamp lighting device according to claim 1, comprising:   At least one of a second magnetic member that covers the second output line and a third magnetic member that covers both the first output line and the second output line is provided. The discharge lamp lighting device according to claim 1 or 2, characterized in that   In the second magnetic body and the third magnetic body, the impedance in the high frequency region from 10 MHz to 100 MHz is higher than the impedance in the low frequency region from 1 MHz to the alternating current flowing through the output cable. 4. The discharge lamp lighting device according to claim 3, wherein the discharge lamp lighting device has a frequency characteristic that increases.

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