JP2000124040A - High-voltage transformer and high-luminance discharge lamp actuating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve circuit design efficiency by restraining the generation of leakage magnetic flux from a magnetic core and making the high-voltage part of a discharge lamp lighting-up circuit into a single unit. SOLUTION: A ring-shaped magnetic core 3, formed by molding soft magnetic metal powder, is accommodated in a case 4. A partition plate 5 is arranged in the case 4 and protrudes to the outside and to the inner diameter center of the case 4. A terminal 6 penetrating the partition 5 is formed on the tip of the partition 5 protruding to the inner diameter. A secondary coil 2 is wound orderly on the outer surface of the case 4, by using the partition 5 as a start point. The winding start 2a and the winding end 2b of the secondary coil 2 are positioned, almost once going round the case 4 accommodating the ring-shaped magnetic core 3 and clamping the partition 5. The winding end 2b of the secondary coil 2 passes a lead-out trench 7 formed on the partition 5 of the case 4 and is connected with a terminal 6a positioned at the tip of the magnetic core inner diameter of the partition 5. The terminal 6a is a connection terminal with a discharge lamp-attaching socket. Two U-shaped one-turn coils are used as a primary coil 1 of a low-voltage side, connected in parallel on a substrate pattern, and constitute a one-turn coil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage transformer, which is a component for lighting a high-intensity discharge lamp mounted on an automobile, a video device, and the like, and a high-voltage generator incorporating the transformer.

[0002]

2. Description of the Related Art Lighting lamps are used for their brightness,
High life and low power are required, and high-intensity discharge lamps have recently been used. A typical high-intensity discharge lamp is an HID (High Intensity Discharge) lamp, which is currently mainly used for automobile headlamps. This H
ID lamps have the advantages of twice the luminance, three times the life, and one-third the power consumption of halogen lamps, which are conventionally used for automobile headlights. It has increased.

However, the HID lamp requires a higher voltage at the time of lighting than the halogen lamp, and thus requires a voltage raising circuit including a high voltage transformer. FIG. 6 is a schematic block diagram of a lighting circuit of the HID lamp.

[0004] An automobile headlamp lighting unit 56 using an HID lamp converts a supply voltage Vi of DC12V to a DC / DC converter 5 in a general private car.
1, after the primary step-up voltage Vc of approximately 400 V DC, the HID lamp 55
Raises the voltage to a high voltage of 10 kV or more, which is a voltage that can be turned on. The trigger circuit 52 is for controlling lamp lighting.

The high voltage transformer 53 is disclosed in
No.-130127 and Utility Model Registration No. 2511451, and schematic cross-sectional views thereof are shown in FIGS.

[0006] JP-A-8-130127 shown in FIG.
The secondary coil 62 of the divided winding is wound on the bobbin 63 penetrating the rod-shaped magnetic core 64, and the case 65 that covers the high-voltage-side secondary coil 62 and the magnetic core 64 and ensures insulation from the low-voltage-side primary coil 61. Since the magnetic core 64 is an open magnetic circuit, it has excellent DC superimposition characteristics. The HID lamp requires a high voltage of 10 kV or more at the time of lighting, but after lighting of the lamp (at a steady state), the DC / DC converter 51 of FIG.
It is necessary that the lighting be continued by the supplied power and the high-voltage transformer 53 should not be saturated by this power. Japanese Patent Application Laid-Open No. 8-130127 is a high-voltage transformer having excellent DC superimposition characteristics in this respect.

[0007] A utility model registration No. 2511 shown in FIG.
No. 451 is a primary coil 71 and a secondary coil 72 of divided winding.
Are wound around bobbins 73 and 74 respectively, and the primary coil 71 is inserted into the hollow hole of the bobbin 74 around which the secondary coil 72 is wound.
Are wound, and each bobbin around which the coil is wound is covered with a case 77, and a U-shaped core 75
Is a transformer in which one side leg is incorporated in the hollow hole of the bobbin 73. This high-voltage transformer has a U-shaped core 75
A gap 76 is provided on the opposing surface to provide the DC superimposition characteristics of the high-voltage transformer required after the HID lamp is turned on. Although this transformer has inferior DC superposition characteristics as compared with JP-A-8-130127, it has excellent inductance value, coil coupling coefficient and small loss.
This makes it possible to reduce the size as compared with No. 127.

[0008]

The two high-voltage transformers each have an arbitrary gap, and a leakage magnetic flux is generated from the gap. This leakage magnetic flux affects various elements of the DC / DC converter 51 and the trigger circuit 52 in the vehicle headlight lighting unit 56, and also adversely affects the high voltage transformer itself. When a conductive material such as a shield is disposed close to the high-voltage transformer, the leakage magnetic flux is increased, and the characteristics of the high-voltage transformer are deteriorated. Therefore, it is difficult to arrange the high-voltage transformer 53 in the lamp lighting unit 56. Further, in a gap structure such as Utility Model Registration No. 2511451, a 400 Hz
A beat occurs at the gap due to the front and rear drive frequencies, so that the core side leg facing surface and the spacer must be carefully fixed.

The arrangement of the DC / DC converter 51 and the high-voltage transformer 53 in the same unit 56 and arranging them on the same circuit board requires the three components Vi, Vc and Vo as shown in FIG.
One voltage is mixed, which complicates component arrangement and circuit pattern design.

An object of the present invention is to solve the above-mentioned problems relating to the leakage magnetic flux of the high-voltage transformer and the lamp lighting unit.

[0011]

According to the present invention, there is provided a high-voltage transformer comprising a magnetic core and a low-voltage-side primary coil and a high-voltage-side secondary coil wound around the magnetic core, wherein the magnetic core comprises a soft magnetic metal powder. The secondary coil is made by insulating the surface of the ring-shaped magnetic core,
A high-voltage transformer that winds the ring-shaped core substantially one round by layer-aligned winding, and the primary coil on the low voltage side is wound within a quarter of the ring-shaped core near the winding start of the secondary coil. It is.

Further, the ring-shaped magnetic core of the present invention is housed in a case made of an insulating resin for insulation from a coil to be wound, and the case has at least one partition plate. The partition plate, which protrudes to the outside and the center of the inner diameter of the case and extends to the center of the inner diameter, extends to the center of the inner diameter of the ring-shaped core, and a terminal extends in the extending portion of the partition plate in a direction penetrating the inner diameter of the ring-shaped core. A terminal is exposed on both flat side surfaces of the magnetic core as connection terminals, and one terminal has a winding end terminal of a secondary coil wound around a case housing the ring magnetic core, which is formed in a partition plate of the case. And the other connection terminal is a high voltage transformer which connects to the electrode of the lamp mounting socket.

The ring-shaped magnetic core formed by molding the soft magnetic metal powder of the present invention is a high-pressure transformer which is a dust core formed by pressing and forming a powder of Fe-Al-Si.

Further, the present invention is a high-intensity discharge lamp starting apparatus in which a high-voltage transformer, a trigger circuit for controlling a lamp lighting operation, and a socket as a lamp mounting part are integrated.

Further, in the present invention, a high-voltage transformer for generating a high voltage of 10 kV or more is housed in a unit separate from a DC / DC converter for supplying a voltage to the high-voltage transformer, and the unit includes the high-voltage transformer of the high-voltage transformer. In addition, there is a trigger circuit for controlling a lamp lighting operation, and a high-intensity discharge lamp starting device in which a lamp mounting portion socket is housed.

The high-voltage transformer incorporated in the high-intensity discharge lamp starting apparatus is a high-intensity discharge lamp starting apparatus incorporating the high-voltage transformer described as the present invention.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The reason why the magnetic core used in the high-voltage transformer of the present invention has a ring shape and soft magnetic metal powder is used for the ring-shaped magnetic core is that soft magnetic metal powder has a lower magnetic permeability than ferrite. It has the characteristic that the saturation magnetic flux density is high. With this characteristic, the DC superimposition characteristic is good without providing the gap where the leakage magnetic flux is generated. The minimum leakage flux is also minimal. That is, the high-voltage transformer of the present invention has a very small leakage magnetic flux, and can prevent the characteristics of the high-voltage transformer from deteriorating due to various elements or nearby conductors. Further, the soft magnetic metal material has a higher Curie temperature Tc than ferrite, has stable characteristics in a wide temperature range from low temperature to high temperature, and is a highly reliable component as a component mounted on an automobile.

The secondary coil on the high voltage side which is wound around the insulated ring-shaped magnetic core is an aligned winding which makes one round of the ring-shaped magnetic core. This is because the secondary coil is aligned and wound,
The potential difference between adjacent coils can be minimized,
In addition, for a high voltage of 10 kV or more of a lamp lighting start voltage, which is a potential difference between the start and end of winding of the secondary coil,
By providing a partition between the beginning and end of winding, it is possible to ensure the insulation of the space, the creepage, and the insulation thickness against high voltage. Furthermore, by enlarging the winding end terminal of the secondary coil, which is at a high potential, to the center of the inner diameter of the ring-shaped magnetic core and drawing it out, the enlargement of the high-voltage transformer can be suppressed.

The reliability can be improved by winding the primary coil on the low voltage side at a position where the potential difference is minimized with respect to the secondary coil on the high voltage side, thereby improving the reliability. It is preferable that the position is closer to the position, and considering the winding frame of the primary coil, the best position is within the range of 1/4 circumference of the magnetic core from the start of the winding of the secondary coil. It is to be noted that the surface of the primary coil is naturally subjected to insulation treatment, and there is also a method in which a one-turn coil is connected to the substrate pattern surface to form a several-turn primary coil other than winding.

By dividing each component necessary for lighting the high-voltage transformer into a DC / DC converter unit and a high-voltage unit, complicated circuit design due to a potential difference can be eliminated. By incorporating (integrally) the lamp mounting socket in the unit, 10
It is possible to eliminate the routing of the high-voltage cable to which kV or more is applied, and to prevent the variation of the high-voltage output characteristics caused by the high-voltage cable. By placing it in the unit, safety for humans can be dramatically improved.

Further, by dividing the unit into a DC / DC converter unit and a high-voltage unit, it is only necessary to change each unit according to the lamp specifications or the power supply of the DC / DC converter. Compared with the unit 56 of the lamp lighting circuit shown in FIG.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
1 shows an external view and a cross-sectional view of the high-voltage transformer of the present invention. 2 and 3 show examples of characteristics of the high-voltage transformer according to the present invention. FIG. 4 shows a schematic block diagram of a lamp lighting circuit using the high-intensity discharge lamp starting device of the present invention. FIG. 5 shows an external view and a cross-sectional view of the high-intensity discharge lamp starting apparatus of the present invention.

FIG. 1 shows the structure of a high-voltage transformer according to the present invention, in which a plan view is shown at the center, a side view is shown above, and a side view showing a cross section AA of the high-voltage transformer is shown below.
A ring-shaped magnetic core 3 formed by molding a soft magnetic metal powder is housed in a case 4 made of an insulating resin.
A partition plate 5 is provided, and the partition plate 5 protrudes to the outside and the center of the inner diameter of the case 4 and protrudes to the inner diameter.
A terminal 6 penetrating through the partition plate 5 is provided at the tip of. On the outer surface of the case 4, the secondary coil 2 is arranged and wound around the partition plate 5 as a starting point, and the case 4 for storing the ring-shaped magnetic core 3 is made substantially one round, and the secondary coil 2 is wound around the partition plate 5. 2a and the winding end 2b are located.

The terminal 2b at the end of winding of the secondary coil 2 is connected to a terminal 6a at the end of the inner diameter of the magnetic core of the partition plate 5 through a lead-out groove 7 formed in the partition plate 5 of the case 4. The terminal 6b is used as a connection terminal to the electric lamp side.

The primary coil 1 on the low voltage side uses two U-shaped one-turn coils and is connected in parallel on a substrate pattern to form a one-turn coil. This primary coil may be configured by connecting a U-shaped one-turn coil on a mounting board in parallel or in series as needed, or by directly winding it around a magnetic core.

The following results were obtained as the performance of the high-voltage transformer of the present invention shown in FIG. As the ring-shaped core 3, an outer diameter of 33 mmφ, an inner diameter of 20 mmφ, and a height of 12.5 mmt of a dust core “Hidust” (manufactured by Hitachi Ferrite Electronics Co., Ltd.) obtained by press-molding an Fe—Al—Si alloy powder were used. This dust core had a magnetic permeability of 90 and a maximum saturation magnetic flux density of 750 mT, and was able to have excellent direct current superposition characteristics without providing a gap. This Fe-Al-
The powder magnetic core of the Si alloy powder has a change in magnetic permeability of 10% or less under a temperature environment of −40 ° C. to + 150 ° C., and is most suitable as an automobile mounting part.

The case 4 for housing the magnetic core has heat resistance,
A PET resin having good insulation properties was used, and the case structure was a fitting type as shown in FIG. 1, and a structure in which the creepage distance of the magnetic core 3 was increased with respect to a high-voltage secondary coil wound around the outer surface of the case.

The secondary coil 2 has a partition plate 5 as a starting point.
0.3 mmφ of one type of UEW was arranged in 153 turns. The potential difference between the adjacent coils could be minimized by the aligned winding. The winding end terminal 2b of the secondary coil is
Through the lead-out groove 7 formed in the partition plate 5, wiring and connection were made to a terminal 6a located at the tip of the inner diameter of the magnetic core of the partition plate 5.

As the primary coil 1, a U-shaped one-turn coil was prepared from an electric wire having a conductor diameter of 1.2 mmφ, and two of them were connected in parallel on a substrate to form a one-turn coil. The primary coil 1 was attached to the secondary coil 2 on the low pressure side, near the beginning of winding.

When a voltage of 380 V DC is applied to the primary coil, Vo = 18.5 kV and Tc = 700 ns shown in FIG.
A high voltage with a pulse width could be obtained. The DC superimposition characteristic of the secondary coil is 1.8 m at 2 A as shown in FIG.
H, and exhibited excellent direct current superposition characteristics.
At this time, the DC resistance of each coil is 0.9 m for the primary coil.
Ω, secondary coil: 1.73 Ω.

The magnetic core may be made of a soft magnetic metal powder such as Mo-P, amorphous or microcrystalline magnetic alloy, instead of the Fe-Al-Si alloy powder. Further, the ring shape of the magnetic core may be a distorted ring shape such as an ellipse,
Furthermore, a ring-shaped magnetic core may be formed by combining split cores. There is an extremely small gap even when a split core is combined to form a closed magnetic circuit ring core, but the beat frequency is very low compared to the gap applied to the ferrite core, and even if a beat occurs, it is very small and practical problem There is no level.

In the case of storing the magnetic core, if the winding start terminal of the secondary coil is provided on the partition plate that protrudes outward, the workability is good, and furthermore, the rod-shaped tip of the inner diameter of the magnetic core of the partition plate is provided. In place of the terminal, by arranging the electric wire so as to penetrate the partition plate similarly to the terminal 6 of FIG. 1, the connectivity of the lamp mounting socket to the electrode can be improved as compared with the rod-shaped terminal. The case 4 does not need to have one partition plate, but by providing a plurality of partition plates, it is possible to improve the interlayer insulation between the coils and to stably fix the high-voltage transformer during installation.

FIG. 4 is a schematic circuit block diagram in which the high-intensity discharge lamp starting device of the present invention is incorporated in an HID lamp lighting circuit of a vehicle headlight. Supply voltage V for private vehicle
i = DC12V is stepped up to around DC400V as a primary step-up voltage Vc by the DC / DC converter 11, and is required to start lighting of the HID lamp 15 by the high-voltage transformer 13 built in the high-intensity discharge lamp starting device 16 of the present invention. Supply a high voltage of 10 kV or more.

As shown in FIG. 5, the high-intensity discharge lamp starting device 16 comprises a trigger circuit 12 for controlling the lighting of the HID lamp, a high-voltage transformer 13 and a mounting socket 14 for the HID lamp 15 as an integrated unit.

The high-voltage transformer 13 is housed in a cylindrical case 20 made of a resin having good heat resistance and good insulation, and is provided between the trigger circuit 12 for controlling lighting of the lamp and the partition wall 2 for insulation.
1 and a protective shield 19 for the trigger circuit 12. The electrode 17 of the mounting socket 14 of the HID lamp 15
Is connected to the connection terminal 6b of the high voltage transformer shown in FIG. The cylindrical case 20 was filled with a resin having a high insulating property to improve heat dissipation, earthquake resistance and insulation.

The voltage supplied from the DC / DC converter 11 is applied to the cords 22 and 23 drawn from the high-intensity discharge lamp starting device 16, and the voltage at which lamp lighting can be started is performed at the terminal 6b of the high-voltage transformer. Conventionally,
Since the wiring from the high-voltage transformer to the HID lamp mounting socket was performed with a cable of at least 20 cm, a voltage drop due to the cable length,
Although the cable picked up electromagnetic noise in the engine room of the automobile and had an adverse effect on the elements of the trigger circuit for lamp lighting control, the high-intensity discharge lamp starting device of the present invention uses the same unit as the high-voltage transformer for the socket. By being contained within, the connection can be made with a length of 1/3 or less of the conventional length, and the above problem can be prevented.

HID lamps have begun to be used in projectors, general lighting, and the like as applications other than automotive headlights, and their power is supplied from an AC power source. Conventional lamp lighting circuit units require a new design. On the other hand, in the lamp lighting circuit using the high-intensity discharge lamp starting device of the present invention, the DC / DC converter 11 shown in FIG. 1 can be easily changed to an AC / DC converter. And improved the work significantly.

[0038]

Since the ring-shaped core made of soft magnetic metal powder is used in the high-voltage transformer of the present invention, there is no need to provide a gap for obtaining DC superimposition characteristics, and no leakage magnetic flux is generated. There is no restriction on the mounting position of the transformer, and the layout of components on the circuit can be reduced. In addition, by dividing the discharge lamp lighting circuit into a DC / DC converter and a high-voltage unit to form a unit, the complexity of different voltages can be eliminated and the circuit can be designed separately.
Design work can be greatly improved. Moreover, the high-voltage transformer, trigger circuit, and lamp mounting socket of the high-voltage section are housed in a single unit as a high-intensity discharge lamp starting device, so that the output voltage resulting from the routing of the cable to which the high voltage is applied is obtained. In particular, not exposing a portion to which a high voltage of 10 kV or more is applied to the outside greatly improves safety for humans.

[Brief description of the drawings]

FIG. 1 is an external view and a sectional view of a high-voltage transformer according to the present invention.

FIG. 2 shows an example of a high-voltage output waveform of the high-voltage transformer of the present invention.

FIG. 3 shows an example of DC superimposition characteristics of the high-voltage transformer of the present invention.

FIG. 4 is a schematic block diagram of a lamp lighting circuit using the high-intensity discharge lamp starting device of the present invention.

FIG. 5 is an external view and a cross-sectional view of a high-intensity discharge lamp starting device of the present invention.

FIG. 6 is a simplified block diagram of a conventional discharge lamp lighting circuit.

FIG. 7 is a schematic sectional view of a conventional high-voltage transformer.

FIG. 8 is a schematic sectional view of another conventional high-voltage transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary coil 2 Secondary coil 3 Ring-shaped magnetic core 4 Case 5 Partition plate 6 Terminal 6a Connection terminal of secondary coil terminal 6b Connection terminal with lamp mounting socket electrode 7 Outgoing groove

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B60Q 1/04 H01F 31/06 501C B60Q 1/04 E

Claims (6)

[Claims] 1. A magnetic core and a low-voltage side coil wound around the magnetic core.
In a high-voltage transformer composed of a secondary coil and a secondary coil on the high voltage side, the magnetic core is a ring-shaped core formed by molding soft magnetic metal powder, and the secondary coil has a surface of the ring-shaped core insulated. Thereafter, the ring-shaped magnetic core is wound substantially one turn by single-layer aligned winding, and the low-voltage-side primary coil
A high-voltage transformer wound around a quarter of the circumference of a ring-shaped magnetic core near the start of the next coil. 2. A ring-shaped magnetic core is housed in a case made of an insulating resin for insulation from a coil to be wound. The case has at least one partition plate, and the partition plate is The partition plate that protrudes to the outside and the center of the inside diameter of the ring core and extends to the center of the inside diameter of the ring core extends to the center of the inside diameter of the ring-shaped core. Are exposed as connection terminals on both flat side surfaces of the secondary coil. On one terminal, the end of the secondary coil wound around the case containing the ring-shaped magnetic core passes through a lead-out groove provided on the partition plate of the case. 2. The high-voltage transformer according to claim 1, wherein the other connection terminal is connected to an electrode of the lamp mounting socket. 3. The ring-shaped magnetic core formed by molding a soft magnetic metal powder is a dust core formed by pressure-molding a powder made of Fe—Al—Si. 2. The high-voltage transformer according to 2. 4. A high-intensity discharge lamp starting device, wherein a high-voltage transformer, a trigger circuit for controlling a lamp lighting operation, and a socket as a lamp mounting portion are formed as an integrated unit. 5. A high-voltage transformer that generates a high voltage of 10 kV or more is housed in a separate unit from a DC / DC converter that supplies a voltage to the high-voltage transformer.
A high-intensity discharge lamp starting device, in which a trigger circuit for controlling a lamp lighting operation and a lamp mounting socket are housed in addition to the high-voltage transformer. 6. A high-voltage transformer incorporated in a high-intensity discharge lamp starting device according to claim 4 or 5.
A high-intensity discharge lamp starting device, comprising the high-voltage transformer according to any one of claims 1 to 3.