JP2002110381A - Lighting device of discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device of a discharge lamp that is made easy in manufacture and enabled a high density mounting. SOLUTION: The discharge lamp lighting device is equipped with a direct current power source E, a direct current step-up and step-down circuit DD that comprises a transformer T1 having a primary to a tertiary coil n1-n3, an inverter circuit INV, and a starting voltage generating circuit IGN that starts a discharge lamp Lp. The transformer T1 is equipped with a transformer body Ta having a terminal pins P1-P10 and in which the both ends of each coil n1-n2 are respectively connected with one of the terminal pins P1-P10. And the winding end of the secondary coil n2 and the winding start of the tertiary coil n3 of the transformer T1 are connected with the terminal pin P5 and the output of the tertiary coil n3 is made independent of the output of the secondary coil n2. By manufacturing the secondary coil n2 and the tertiary coil n3 of the transformer T1 continuously in one body, the manufacture of the transformer T1 is made easy, and the electric components constituting the above each circuit can be mounted in high density.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device.

[0002]

2. Description of the Related Art A DC power supply and a transformer having primary to tertiary windings are provided, and a power supply voltage of the DC power supply applied to the primary winding is passed through a secondary winding and a tertiary winding, respectively. A DC buck-boost circuit that converts and outputs a predetermined DC voltage, and an inverter circuit that converts a DC voltage output from the DC buck-boost circuit through a secondary winding of a transformer into an AC voltage and applies the AC voltage to a discharge lamp; Provided is a discharge lamp lighting device including: a starting voltage generation circuit that starts a discharge lamp by applying a high-voltage pulse voltage to the discharge lamp by a DC voltage output from a DC step-up / step-down circuit via a tertiary winding of a transformer. Have been.

[0003]

The above-mentioned transformer has a transformer main body having a plurality of terminals, respectively, and is configured by connecting both ends of primary to tertiary windings to the respective terminals.

However, when the above-described transformer is configured as described above, it is necessary to separately manufacture the above-described primary to tertiary windings and connect both ends to each terminal of the transformer main body. Problem. Also, in order to apply a high pulse voltage to the discharge lamp in the starting voltage generating circuit, it is necessary to generate a high voltage in the tertiary winding of the transformer, and the tertiary winding is connected to the starting voltage generating circuit. A high voltage is applied to the wiring to be performed.
If the wiring to which such a high voltage is applied is routed, the surrounding electrical components may be affected by noise or the like, so that it is difficult to mount the electrical components constituting each circuit at high density. Was.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a discharge lamp lighting device which can be easily manufactured and can be mounted at a high density.

[0006]

In order to achieve the above object, the present invention provides a DC power supply and a transformer having primary to tertiary windings. A DC step-up / down circuit that converts a power supply voltage of a power supply into a predetermined DC voltage through a secondary winding and a tertiary winding and outputs the DC voltage,
An inverter circuit that converts a DC voltage output from a DC buck-boost circuit through a secondary winding of a transformer into an AC voltage and applies it to a discharge lamp, and an output from a DC buck-boost circuit through a tertiary winding of a transformer And a starting voltage generating circuit for starting the discharge lamp by applying a high pulse voltage to the discharge lamp by the applied DC voltage, wherein the transformer includes a transformer main body having a plurality of terminals and includes a primary to tertiary winding. Both ends are connected to the respective terminals, and the winding end of the secondary winding of the transformer and the winding start of the tertiary winding, or the winding start of the secondary winding of the transformer and the winding end of the tertiary winding are determined. The output of the tertiary winding is independent of the output of the secondary winding, and is connected to any one of the terminals of the transformer main body. By continuously manufacturing the beginning of winding As a result, the transformer can be easily manufactured, and the output of the tertiary winding is made independent, so that the degree of freedom in the layout design between the transformer and the above circuits can be increased. Even when a high voltage is applied to the wiring connecting the winding and the starting voltage generating circuit, the influence of noise can be suppressed, and the electric components constituting each circuit can be mounted at a high density.

According to a second aspect of the present invention, in the first aspect, one end of the tertiary winding opposite to the secondary winding is connected to a terminal provided at an end of the transformer main body. Thus, the electric components constituting each circuit can be easily and densely mounted.

According to a third aspect of the present invention, in the first or second aspect of the present invention, noise of the DC voltage output from the DC step-up / step-down circuit via the tertiary winding of the transformer is removed, and the DC voltage from which the noise is removed is provided. And a substrate on which at least one or a plurality of electrical components and a transformer constituting the filter circuit are mounted.
A terminal of the transformer main body to which one end of the secondary winding opposite to the secondary winding is connected is disposed near the filter circuit, and a wiring for connecting the terminal of the transformer main body to the filter circuit is provided. By shortening the length, generation of noise from the tertiary winding can be further suppressed, and as a result, electric components constituting each circuit can be more easily and densely mounted on the board.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, an intermediate tap is provided in at least one of the primary to tertiary windings of the transformer.
By switching one end of the primary to tertiary windings provided with an intermediate tap and the intermediate tap, the output voltage from the DC step-up / step-down circuit can be varied by changing the turns ratio of the transformer. it can.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, there is provided a wiring distance detecting means for detecting at least a length of a wiring connecting the inverter circuit and the starting voltage generating circuit; Switching means for switching any one of the next windings and the intermediate tap to change the winding ratio, and a control unit for controlling the switching means in accordance with the detection output of the wiring distance detection means. Characteristically, when the voltage applied to the discharge lamp fluctuates, for example, by changing the length of the wiring between the inverter circuit and the starting voltage generation circuit, the length of the wiring is detected by the wiring distance detecting means. The control unit changes the turn ratio of the transformer to the switching unit according to the detection output of the wiring distance detection unit, thereby changing the output voltage from the DC buck-boost circuit and stabilizing the output to the discharge lamp.

A sixth aspect of the present invention is characterized in that, in the fifth aspect of the present invention, the wiring distance detecting means detects the length of the wiring based on the lamp current, and has the same effect as in the fifth aspect.

According to a seventh aspect of the present invention, in any one of the fourth to sixth aspects of the present invention, a control unit for controlling at least an output of the inverter circuit, and an operating power supply of the control unit using power supplied from a primary winding of the transformer. A control power supply unit for creating and supplying
An inductance switching means for switching one end of the primary winding provided with the intermediate tap and the intermediate tap to vary the inductance of the primary winding of the transformer, a power supply voltage detecting means for detecting a power supply voltage of the DC power supply, and a power supply Switching control means for controlling the inductance switching means in accordance with the detection output of the voltage detection means, wherein the switching control means detects the detection output of the power supply voltage detection means even when the power supply voltage of the DC power supply fluctuates. By changing the inductance of the primary winding by the inductance switching means according to the above, the power supplied to the control power supply unit can be kept within a predetermined range, and a stable operation power supply can be supplied from the control power supply unit to the control unit. .

[0013]

(Embodiment 1) As shown in FIGS. 1 and 2, this embodiment includes a DC power supply E and a transformer T1 having primary to tertiary windings n1, n2 and n3. 1
A DC voltage step-up / down circuit DD for converting and supplying a power supply voltage of the DC power supply E applied to the next winding n1 to a predetermined DC voltage via the secondary winding n2 and the tertiary winding n3, respectively; An inverter circuit INV that converts a DC voltage output from the DC step-up / down circuit DD through the secondary winding n2 to an AC voltage and applies the AC voltage to the discharge lamp Lp, and a DC step-up / down through the tertiary winding n3 of the transformer T1. Control for controlling the outputs of a starting voltage generating circuit IGN for starting the discharge lamp Lp by applying a high-voltage pulse voltage to the discharge lamp Lp by the DC voltage output from the pressure circuit DD, and a DC step-up / down circuit DD and an inverter circuit INV Unit CN. Further, the present embodiment
An input filter circuit F1 and an output filter circuit F2 are provided. The input filter circuit F1 removes high-frequency noise included in the power supply voltage of the DC power supply E, and supplies the power supply voltage from which the noise has been removed to the primary winding of the transformer T1. Applied to the line n1, the output filter circuit F2 removes high frequency noise of the DC voltage output from the DC step-up / step-down circuit DD via the tertiary winding n3 of the transformer T1, and starts the DC voltage from which the noise has been removed. This is output to the voltage generation circuit IGN.

The DC step-up / step-down circuit DD is connected to the transformer T1.
An FET1 connected to the primary winding n1 of the transformer T1 and a negative electrode of the DC power supply E; a resistor R1 connected between the source and the gate of the FET1; a gate of the FET1;
N2 and a secondary winding n of the transformer T1.
2, a capacitor C1 connected in parallel via a diode D1, and a diode D2 connected to a tertiary winding n3 of the transformer T1.
So-called forward type DC / D provided with a capacitor C2 connected in parallel via a resistor, and a resistor R3 connected to a connection point between the diode D1 and the capacitor C1 and the control unit CN.
It is a C converter. Also, the secondary winding n of the transformer T1
The secondary and tertiary winding n3 are connected in series, and the connection point is
Is connected to the negative electrode side.

Further, the DC step-up / step-down circuit DD is provided with a control power supply section CE for creating and supplying an operation power supply for the control section CN and an operation power supply for a drive circuit Dv described later provided in the inverter circuit INV. Department CE is 1
Each of the above-mentioned operation power supplies is created by receiving power supplied from a DC power supply E via a diode D3 from a connection point between the next winding n1 and the FET1.

The inverter circuit INV has four FETs 2
And a drive circuit Dv for turning on / off each of the FETs 2 to 5, a series circuit of the FETs 2 and 3, and a FET
4 and 5 are connected to both ends of the secondary winding n2 of the transformer T1 via the diode D1 of the DC step-up / step-down circuit DD. The discharge lamp Lp is connected between the connection points of the FETs 2 and 3 and the FETs 4 and 5 via a secondary winding n22 of a pulse transformer T2 described later provided in the starting voltage generation circuit IGN.

The output filter circuit F2 includes resistors R4, R5
And a capacitor C3 having one end connected to the inductor L1 and the other end grounded, and removes high-frequency noise included in the DC voltage from the DC step-up / step-down circuit DD.

The starting voltage generating circuit ING has one end connected to the connection point between the inductor L1 and the capacitor C3 of the output filter circuit F2, and the other end connected to the FE of the inverter circuit INV.
A capacitor C4 and a resistor R6 connected to the connection point of T4 and T5, a pulse transformer T2 having primary and secondary windings n21 and n22, and a primary winding n2 of the pulse transformer T2
1, a gap element Ga connected in parallel with the resistor R6.
p.

Here, the basic operation of the present embodiment will be briefly described.

First, the control unit CN outputs a drive signal to the FET 1 via the resistor R2 of the DC buck-boost circuit DD,
1 is repeatedly turned on / off periodically. As a result, the power supply voltage of the DC power supply E is intermittently applied to the primary winding n1 of the transformer T1, and voltages are induced in the secondary winding n2 and the tertiary winding n3. D
1, D2 and capacitors C1, C
2 for smoothing. As a result, a DC voltage obtained by converting the power supply voltage of the DC power supply E into a desired voltage value according to the turns ratio of the transformer T1 is output from both ends of the capacitors C1 and C2 of the DC buck-boost circuit DD.

Then, the charge is accumulated in the capacitor C4 of the starting voltage generating circuit IGN by the DC voltage (voltage across the capacitor) from the capacitor C2, and when the voltage across the capacitor C4 reaches the discharge starting voltage of the gap element Gap, The charge accumulated in the capacitor C4 after the gap element Gap breaks over is released through the primary winding n21 of the pulse transformer T2. As a result, a high-voltage pulse voltage corresponding to the turn ratio of the pulse transformer T2 is generated on the secondary side of the pulse transformer T2, and the discharge lamp Lp is broken down, and the discharge lamp Lp shifts to a lighting state.

After the dielectric breakdown of the discharge lamp Lp, the control unit C
N: F is applied to the drive circuit Dv of the inverter circuit INV.
When ET2,5 are on and FET3,4 are off, FE
The state where T2 and T5 are off and the FETs 3 and 4 are on is alternately repeated. Thereby, the DC voltage from the capacitor C1 of the DC step-up / step-down circuit DD is converted into an AC voltage, applied to the discharge lamp Lp via the secondary winding n22 of the pulse transformer T2, and the lighting state of the discharge lamp Lp is continued. It is.

The control unit CN includes a lamp current detection unit CN1 for detecting a lamp current from a voltage applied to a resistor R7 connected to the negative side of the DC power supply E, and a power supply voltage for detecting a power supply voltage of the DC power supply E. A detection unit CN2, a lamp voltage detection unit CN3 for detecting a lamp voltage from a voltage input via the resistor R3, and a primary side detection unit CN4 for detecting a current flowing through the primary winding n1 of the transformer T1. , The duty ratio and the repetition period are adjusted in accordance with these detection outputs to turn on / off the FET 1 and the drive circuit D
v2 also adjusts the duty ratio and the repetition period so that FET2
5 are turned on / off to control the outputs of the DC step-up / step-down circuit DD and the inverter circuit INV.

Here, the structure of the transformer T1 of this embodiment will be briefly described with reference to FIGS. The transformer T1 includes a substantially rectangular frame-shaped transformer body Ta having terminal pins P1 to P10. Terminal pins P1 to P
Numerals 5 are arranged at substantially equal intervals along the longitudinal direction on one of both sides of the transformer main body Ta substantially opposite to each other, and similarly, the terminal pins P6 to P10 are also substantially equal along the longitudinal direction on the other side. It is arranged at intervals. The transformer T1 is 1
Both ends of the next winding n1 are connected to terminal pins P1 and P6,
The start of winding of the next winding n2 is connected to the terminal pin P10,
The winding end of the next winding n3 is connected to the terminal pin P8, and the winding end of the secondary winding n2 and the winding start of the tertiary winding n3 are connected to the same terminal pin P5. FIG. 3 omits the iron core for increasing the voltage conversion efficiency and other members constituting the transformer T1, and simplifies the shapes of the windings n1, n2, and n3.

In this embodiment, as described above, the secondary winding n
Since the end of the winding of No. 2 and the start of the winding of the tertiary winding are connected to the same terminal pin P5, for example, the secondary winding n2 and the tertiary winding n3 of the transformer T1 are continuously and integrally manufactured. , And the transformer T1 can be easily manufactured. Further, by making the output of the tertiary winding n3 independent of the output of the secondary winding n2, the degree of freedom in the layout design between the transformer T1 and each circuit such as the output filter circuit F2 can be increased. As a result, Even if a high voltage is applied to the wiring connecting the tertiary winding n3 and the starting voltage generation circuit IGN, the influence of noise can be suppressed, and the electric components constituting each circuit can be mounted at a high density.

In the present embodiment, the transformer T1 is configured such that the winding end of the secondary winding n2 and the winding start of the tertiary winding n3 are connected to the same terminal pin. The winding start and the winding end of the tertiary winding n3 may be connected to the same terminal pin. (Embodiment 2) Since the basic configuration in this embodiment is common to Embodiment 1, the same reference numerals are given to the common parts, and the description thereof will be omitted, and only the characteristic parts of this embodiment will be described in detail. I do.

As shown in FIGS. 5 and 6, the transformer T1 of the present embodiment is different from the first embodiment in that the winding start of the secondary winding n2 is connected to the terminal pin P8 and the secondary winding n2 is The winding end of the tertiary winding n3 and the winding start of the tertiary winding n3 are connected to the same terminal pin P3, and the winding end of the tertiary winding n3 on the side opposite to the secondary winding n2 side is connected to the transformer body Ta.
Is connected to a terminal pin P10 located at an end (corner) of the terminal. Thus, the secondary winding n2 in the tertiary winding n3
By connecting one end on the opposite side to the terminal pin P10 located at the end of the transformer main body Ta, it is possible to easily and densely mount electric components constituting each circuit.

In this embodiment, as shown in FIGS. 7 and 8, each of the electric components constituting the DC step-up / step-down circuit DD including the transformer T1, the input filter circuit F1, the output filter circuit F2, and the inverter circuit INV A printed wiring board B on which each of the electrical components constituting each is mounted is provided. The printed wiring board B includes an input section IN for connecting to a DC power supply E, a starting voltage generation circuit IGN, and a discharge lamp L.
and an output section OUT for connecting to p.

Here, when the transformer T1 is mounted on the printed wiring board B, the transformer body Ta to which one end of the tertiary winding n3 on the side opposite to the secondary winding n2 is connected.
Is disposed in the vicinity of the output filter circuit F2. As a result, the length of the wiring connecting the terminal pin P10 and the output filter circuit F2 is shortened, so that the generation of noise from the tertiary winding can be further suppressed. B can be more easily and densely mounted. (Embodiment 3) By the way, when the discharge lamp Lp and the starting voltage generating circuit IGN and the output filter circuit F2, the inverter circuit INV and the DC step-up / step-down circuit DD are arranged at a distance from each other, the starting voltage generating circuit IGN and the output It is necessary to increase the length of the intermediate harness in which the wiring connecting the filter circuit F2 and the wiring connecting the starting voltage generation circuit IGN and the inverter circuit INV are bundled. As described above, when the length of the intermediate harness is changed depending on the location where each circuit is arranged, the output to the discharge lamp Lp fluctuates by changing the values of the impedances R11, R12, and R13 due to the intermediate harness shown in FIG. May be done.

For example, as shown by a curve a in FIG. 10, even if the value of the output voltage from the inverter circuit INV is the rated voltage value V0 of the discharge lamp Lp, the length Lm of the intermediate harness is larger than the predetermined length Lm1. Becomes longer, the voltage value V of the AC voltage actually applied to the discharge lamp Lp becomes smaller than the rated voltage value V0.

Therefore, in this embodiment, as shown in FIG. 11, an intermediate tap t1 is provided on the secondary winding n2 of the transformer T1 of the second embodiment, and this intermediate tap t1 is connected to, for example, a terminal pin P9 of the transformer main body Ta. Connecting.

Further, the DC step-up / step-down circuit DD of the present embodiment
As shown in FIG. 9, the terminal pin P8 to which one end of the secondary winding n2 is connected and the above-mentioned terminal pin P9 are switched and connected to the diode D1, and the primary and secondary windings n1 and n1 of the transformer T1 are switched. An output switching unit SW1 that makes the turn ratio of n2 variable is provided. The output switching unit SW1 is, for example, as shown in FIG. 12, a transistor 6 connected via a resistor R8 between a terminal pin P8 of a transformer T1 and a diode D1.
A transistor 7 connected between the terminal pin P9 of the transformer T1 and the diode D1 via a resistor R9, and a resistor R10 connected to a connection point between the resistor R8 and the transistor 6 and a base of the transistor 7. I have.

The control unit CN includes a reference voltage output unit Vout for outputting a reference voltage, a detection voltage corresponding to the lamp current output from the lamp current detection unit CN1, and a reference voltage output unit Vout.
and a comparator Cp that compares a reference voltage from out and outputs a switching signal according to the comparison result. The control unit CN turns on / off the transistor 8 according to the output of the switching signal and grounds / non-grounds the base of the transistor 6 of the output switching unit SW1, thereby controlling on / off of the transistor 6 and the output switching unit. SW1 turns off transistor 7 when transistor 6 is turned on, and turns on transistor 7 when transistor 6 is turned off. The circuit diagram shown in FIG. 12 shows the secondary side output and the tertiary side output of the transformer T1 on the high side,
Here is an example when the low side is reversed.

For example, when the terminal pin P9 is connected to the output switching section SW1
1 is connected to the diode D1 by
As shown by a curve b of 0, the output voltage from the inverter circuit INV is previously set to a voltage value V1 larger than the rated voltage value V0 of the discharge lamp Lp, and the length Lm of the intermediate harness is, for example, L
Approximately 3 [m] longer than m1 and impedance R1
2, the rated voltage V0 is applied to the discharge lamp Lp even if a voltage drop occurs due to R13. When the length Lm of the intermediate harness is further increased to, for example, about 5 [m] in the above-described state, the above-described voltage drop further occurs, and the voltage value V applied to the discharge lamp Lp becomes the rated voltage. It becomes smaller than the value V0.

However, in the present embodiment, the lamp current detector CN1 of the controller CN is used as a wiring distance detecting means, and the lamp current I is detected by the lamp current detector CN1.
When the lamp current I decreases due to the above-described voltage drop and the control unit CN determines from the output of the comparator Cp that the detection voltage of the lamp current detection unit CN1 is smaller than the reference voltage and the length of the intermediate harness is longer, A switching signal is output from the comparator Cp to turn on the transistor 6 and turn off the transistor 7 of the output switching unit SW1. Thereby, the terminal pin P8 to which one end of the secondary winding n2 is connected.
Is connected to the diode D1, the turn ratio of the primary and secondary windings n1 and n2 of the transformer T1 changes, and the transformer T1
Output on the secondary side increases. As a result, the curve c in FIG.
As shown in FIG. 5, the output voltage value of the inverter circuit INV is set to V2 larger than V1, and even if a voltage drop occurs, the voltage value V applied to the discharge lamp Lp is changed to the rated voltage value V of the discharge lamp Lp.
By keeping it at 0, the output to the discharge lamp Lp can be stabilized and the lighting performance can be secured.

In the present embodiment, the discharge lamp Lp generated due to the change in the impedance of the intermediate harness is a factor.
As described above, the output voltage of the DC buck-boost circuit DD is changed on the basis of the lamp current. Of the discharge lamp L
Lighting performance can be ensured by preventing excessive stress on p and insufficient output. In the present embodiment, the control unit CN
The output switching unit SW1 is controlled by the user, but the output switching unit SW1 may manually switch the terminal pins P8 and P9.
At this time, the output from the DC step-up / step-down circuit DD can be adjusted according to the use state. (Embodiment 4) Since the basic configuration in this embodiment is common to Embodiment 1 or 2, the same reference numerals are given to the common parts, and the description thereof will be omitted, and only the characteristic parts of this embodiment will be described in detail. Will be described.

In the present embodiment, as shown in FIG. 13, unlike the third embodiment, an intermediate tap is provided in the primary winding n1 of the transformer T1, and the DC step-up / step-down circuit DD is connected to the primary winding n1. Of the primary winding n1
Switching unit S for changing the inductance of
W2 is provided. Further, the control power supply unit CE of the present embodiment
Creates an operating power supply for the control unit CN from the power supplied from the primary winding n1, the control unit CN operates as switching control means, and controls the inductance switching unit SW2 according to the detection output of the power supply voltage detection unit CN2. Control. Accordingly, even when the power supply voltage of the DC power supply E fluctuates, the control unit CN changes the inductance of the primary winding n1 to the inductance switching unit SW2 according to the detection output of the power supply voltage detection unit CN4. The power supply to the unit CE is prevented from being short and excessive voltage stress is prevented, the power supply is kept within a predetermined range, and a stable operation power can be supplied from the control power supply unit CE to the control unit CN.

[0038]

According to the first aspect of the present invention, a DC power supply and a transformer having primary to tertiary windings are provided, and the power supply voltage of the DC power supply applied to the primary winding is reduced by the secondary winding and the primary winding, respectively. A DC buck-boost circuit that converts and outputs a predetermined DC voltage through a tertiary winding, and a DC lamp that converts a DC voltage output from a DC buck-boost circuit through a secondary winding of a transformer into an AC voltage And a starting voltage generating circuit for starting the discharge lamp by applying a high pulse voltage to the discharge lamp by a DC voltage output from the DC step-up / step-down circuit via the tertiary winding of the transformer. , The transformer comprises a transformer main body having a plurality of terminals, and each end of a primary to tertiary winding is connected to each of the terminals. Start of winding, or start of winding of secondary winding of transformer and 3 Since the winding end of the winding is connected to any one of the terminals of the transformer main body and the output of the tertiary winding is made independent of the output of the secondary winding, for example, the winding end of the secondary winding of the transformer and the winding end By making the winding start of the next winding continuously and integrally, the manufacture of the transformer can be facilitated. Further, by making the output of the tertiary winding independent, the arrangement of the transformer and each of the above circuits can be made. The degree of freedom in design can be increased, and as a result, even when a high voltage is applied to the wiring connecting the tertiary winding and the starting voltage generating circuit, the influence of noise is suppressed, and the electric components constituting each of the above circuits are reduced. Can be mounted at a high density.

According to a second aspect of the present invention, one end of the tertiary winding on the side opposite to the secondary winding is connected to a terminal provided at an end of the transformer main body. There is an effect that mounting can be performed easily and with high density.

According to a third aspect of the present invention, there is provided a filter for removing noise of a DC voltage output from a DC step-up / down circuit via a tertiary winding of a transformer and outputting the noise-free DC voltage to a starting voltage generating circuit. A circuit, and at least one or more electric components constituting a filter circuit and a substrate on which a transformer is mounted, and a terminal of a transformer body to which one end of the tertiary winding opposite to the secondary winding is connected. Since it is arranged near the filter circuit, the length of the wiring connecting the terminal of the transformer body and the filter circuit can be shortened, and the generation of noise from the tertiary winding can be further suppressed. There is an effect that electric components constituting each circuit can be more easily and densely mounted thereon.

According to a fourth aspect of the present invention, at least one of the primary to tertiary windings of the transformer is provided with an intermediate tap, so that any one of the primary to tertiary windings provided with the intermediate tap is provided. By switching between one end of the
There is an effect that the output voltage from the DC step-up / step-down circuit can be changed by changing the turns ratio of the transformer.

According to a fifth aspect of the present invention, there is provided a wiring distance detecting means for detecting at least a length of a wiring connecting the inverter circuit and the starting voltage generating circuit, and any one of the primary to tertiary windings provided with an intermediate tap. Switching means for switching one end and the intermediate tap to change the turns ratio, and a control unit for controlling the switching means in accordance with the detection output of the wiring distance detecting means. Even when the voltage value applied to the discharge lamp fluctuates due to the change in the length of the wiring between the circuits, the wiring length detecting means detects the length of the wiring, and the control unit detects the wiring distance detecting means. By changing the turn ratio of the transformer by the switching means in accordance with the output, the output voltage from the DC step-up / step-down circuit can be changed to stabilize the output to the discharge lamp.

According to a sixth aspect of the present invention, the wiring distance detecting means comprises:
Since the length of the wiring is detected based on the lamp current, the same effect as that of the fifth aspect is obtained.

According to a seventh aspect of the present invention, there is provided a control unit for controlling at least the output of the inverter circuit, a control power supply unit for generating and supplying an operation power supply for the control unit with power supplied from the primary winding of the transformer, and an intermediate tap. Switching means for switching one end of a primary winding provided with a coil and an intermediate tap to vary the inductance of the primary winding of the transformer, power supply voltage detecting means for detecting a power supply voltage of a DC power supply, and power supply voltage detection Switching control means for controlling the inductance switching means according to the detection output of the means, so that even when the power supply voltage of the DC power supply fluctuates, the switching control means switches the inductance in accordance with the detection output of the power supply voltage detection means. Means 1
By changing the inductance of the next winding, there is an effect that power supplied to the control power supply unit is kept within a predetermined range, and stable operation power can be supplied from the control power supply unit to the control unit.

[Brief description of the drawings]

FIG. 1 is a schematic circuit block diagram showing a first embodiment.

FIG. 2 is a schematic circuit diagram of the same.

FIG. 3 is a schematic configuration diagram showing a main part of the transformer according to the first embodiment;

FIG. 4 is a circuit diagram of the transformer according to the first embodiment;

FIG. 5 is a schematic configuration diagram illustrating a main part of a transformer according to a second embodiment.

FIG. 6 is a circuit diagram of the transformer according to the first embodiment;

FIG. 7 is an arrangement configuration diagram of each electric component on the printed wiring board when the transformer is mounted on the printed wiring board.

FIG. 8 is a perspective view of the printed wiring board according to the first embodiment.

FIG. 9 is a schematic circuit diagram showing a third embodiment.

FIG. 10 is an explanatory diagram of the above.

FIG. 11 is a circuit diagram of the transformer of the above.

FIG. 12 is a main part circuit diagram of the same.

FIG. 13 is a schematic circuit diagram showing a fourth embodiment.

[Explanation of symbols]

 CN control unit DD DC step-up / step-down circuit E DC power supply F1 input filter circuit F2 output filter circuit IGN starting voltage generation circuit INV inverter circuit T1 transformer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Noriyuki Sato 1048 Kazuma, Kadoma, Osaka Prefecture F-term in Matsushita Electric Works, Ltd.

Claims (7)

[Claims] 1. A power supply comprising a DC power supply and a transformer having primary to tertiary windings, wherein a power supply voltage of the DC power supply applied to the primary winding is passed through a secondary winding and a tertiary winding, respectively. A DC buck-boost circuit that converts and outputs a predetermined DC voltage, and an inverter circuit that converts a DC voltage output from the DC buck-boost circuit through a secondary winding of a transformer into an AC voltage and applies the AC voltage to a discharge lamp; A starting voltage generating circuit for starting a discharge lamp by applying a high-voltage pulse voltage to the discharge lamp by a DC voltage output from a DC step-up / step-down circuit through a tertiary winding of the transformer; And a transformer main body having the ends of the primary to tertiary windings connected to the respective terminals, and the winding end of the secondary winding and the winding start of the tertiary winding, or the winding of the transformer The start of the next winding and the end of the tertiary winding A discharge lamp lighting device, wherein the output of the tertiary winding is made independent of the output of the secondary winding by connecting to any one of the terminals of the transformer body. 2. The discharge lamp lighting device according to claim 1, wherein one end of the tertiary winding on the side opposite to the secondary winding is connected to a terminal provided at an end of the transformer main body. 3. A filter circuit for removing noise of a DC voltage output from a DC step-up / step-down circuit via a tertiary winding of a transformer, and outputting the noise-free DC voltage to a starting voltage generation circuit; A circuit board for mounting one or more electric components constituting a circuit and a transformer, a terminal of the transformer main body to which one end of the tertiary winding on the side opposite to the secondary winding is connected near the filter circuit; The discharge lamp lighting device according to claim 1, wherein the discharge lamp lighting device is disposed. 4. The discharge lamp lighting device according to claim 1, wherein an intermediate tap is provided in at least one of the primary to tertiary windings of the transformer. 5. A wiring distance detecting means for detecting a length of a wiring connecting at least an inverter circuit and a starting voltage generating circuit, and one end of one of first to tertiary windings provided with an intermediate tap and an intermediate portion. 5. The discharge lamp lighting device according to claim 4, further comprising: switching means for changing a winding ratio by switching taps; and a control unit for controlling the switching means in accordance with a detection output of the wiring distance detecting means. . 6. The discharge lamp lighting device according to claim 5, wherein the wiring distance detecting means detects the length of the wiring based on the lamp current. 7. A control unit comprising: a control unit for controlling at least an output of an inverter circuit; a control power supply unit for creating and supplying an operation power supply for the control unit with power supplied from a primary winding of a transformer; Inductance switching means for changing the inductance of the primary winding of the transformer by switching one end of the secondary winding and the intermediate tap, power supply voltage detecting means for detecting the power supply voltage of the DC power supply, and detection output of the power supply voltage detecting means. The discharge lamp lighting device according to any one of claims 4 to 6, further comprising: switching control means for controlling the inductance switching means in response.