JP2000012273A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the generation of power source noise and make a device small and thin by installing two transformers, switching circuits, and transformer control circuits, and driving them with a switching control signal having a different phase each other. SOLUTION: Two transformers 123, 33, two switching transistors 41, 42, and two transformer control circuits A, B are installed. By shifting a chopping wave reference signal for being input in the transformer control circuit A by 180 degrees with an inverter 61, an inverse transformer control signal is outputted from the transformer control circuit B. Since the small and high speed transistors 41, 42 can be used in a switching circuit, switching loss is reduced and efficiency is enhanced. The width of upper and lower limits of power source current is made narrow, noise component contained in the power source current is reduced, and an LC filter 9 can be made small. A load born by each component is made small, and use of the small component is made possible, and a device is also made thin.

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 for generating a voltage to be supplied to a discharge lamp via a transformer.

[0002]

2. Description of the Related Art As described in Japanese Patent Application Laid-Open No. 9-306684, a lighting device for generating a voltage to be supplied to a discharge lamp by a transformer is generally known. FIG.
FIG. 4 is a configuration diagram showing a conventional discharge lamp lighting device for use in a vehicle, and FIG. 4 is a waveform diagram showing signal waveforms of the conventional discharge lamp lighting device. In the drawing, 1 is connected to a DC power supply (12 V) 2 Primary winding 3, secondary winding 3 for boosting the voltage generated in primary winding 1, 4 transformer composed of primary winding 1 and secondary winding 3, 5 primary side A transistor (switching circuit) 6 for turning on / off the voltage applied to the winding 1 receives the triangular wave 6a shown in FIG. 4A and the feedback voltage 14a from the feedback circuit 14, and is shown in FIG. 4B. A transformer control circuit that outputs a rectangular-wave transistor drive signal, 7 is a transformer current flowing between the DC power supply 2 and the primary winding 1 (see FIG. 4C), 8 is a power supply smoothed by an LC filter 9 The current (see FIG. 4D) .

[0003] 10 is a smoothing circuit for smoothing the voltage generated in the secondary winding 3, 11 is an H bridge (discharge voltage supply circuit) for inverting the polarity of the current applied to the discharge lamp 13, 12
Is the high voltage (about 20 k
A high-voltage generation circuit 13 for generating V) is a vehicle-mounted discharge lamp (HID), which is 1000 to 1500 lm in a commonly used halogen lamp, for example.
It is a very bright discharge lamp because it has 200 lm.

Next, the operation will be described. The power supply voltage from the DC power supply 2 applied to the primary winding 1 of the transformer 4 is turned on / off (chopping) via the transistor 5.
Then, a voltage boosted from the power supply voltage is generated in the secondary winding 3 of the transformer 4. Then, the voltage boosted from the power supply voltage is applied to the secondary winding 3 of the transformer 4 by the smoothing circuit 10, and the voltage is applied to the discharge lamp 13 while the polarity of the current is inverted by the H bridge 11. When the discharge lamp 13 is turned on, a high voltage of about 20 kV is required, so that the high voltage is applied to the discharge lamp 13 via the high voltage generation circuit 12.

In the discharge lamp lighting device as described above, the power supply voltage from the DC power supply 2 is turned on / off via the transistor 5, so that the power supply current 8 is as shown in FIG. It becomes a triangular wave signal of about 100 KHz with a high peak value. However, when this triangular wave signal of about 100 KHz is frequency-resolved, 1 MHz or 100 MH
High frequency signals such as z are included. Then, such a high-frequency signal as 1 MHz or 100 MHz is output from the power supply harness, and the AM band and the FM
In some cases, noise entered the band as well as other electronic devices.

In the above-described discharge lamp lighting device, one large transformer 4 is used to obtain a necessary high voltage.
Further, since the power supply voltage is increased by the transistor 5, the configuration of the entire device cannot be reduced in size and thickness. In addition, since the change in the power supply current is large, the LC filter 9 also needs to be large in size to cope with this change.

[0007]

Since the conventional discharge lamp lighting device is constructed as described above, noise generated on the primary winding 1 side of the transformer 4 is output from the power supply harness, and the noise of the vehicle-mounted radio is reduced. There are problems such as entering the AM band and the FM band, and at the same time, entering other electronic devices, resulting in adverse effects.

In addition, since the power supply voltage is boosted by one transformer 4 and transistor 5, the transformer, transistor, LC filter, and the like are increased in size, and the overall configuration of the device cannot be reduced in size and thickness. There were challenges.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is possible to reduce the occurrence of noise and to reduce the size and thickness of the entire device by using a discharge lamp. The aim is to obtain a device.

[0010]

A discharge lamp lighting device according to the present invention includes at least two or more transformers, a switching circuit, and a transformer control circuit, and each of the transformer control circuits has a different transistor drive signal having a different phase. Is output.

A discharge lamp lighting device according to the present invention includes two transformers, a switching circuit, and two transformer control circuits, and the phase of a transistor drive signal output from one of the transformer control circuits is shifted by 180 degrees by an inverter. It is.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a configuration diagram showing a discharge lamp lighting device according to Embodiment 1 of the present invention, and FIG. 2 is a waveform diagram showing signal waveforms of the discharge lamp lighting device according to Embodiment 1 of the present invention. In the conventional discharge lamp lighting device, only one transformer 4, the switching circuit 5, and the transformer control circuit 6 are provided. However, in the discharge lamp lighting device of the present invention, the transformers 23, 3 having a relatively small capacity are used.
3. Two switching circuits 41 and 42 and two transformer control circuits 51 and 52 are provided, and a transistor drive signal as a switching circuit control signal for driving the switching circuit output from the transformer control circuit 51 and a transformer control circuit 52 are provided. The phase of the output transistor drive signal is shifted by 180 degrees. In the figure, 2 is a DC power supply, 9 is an LC filter, 1
1 is an H bridge (discharge voltage supply circuit), 12 is a high voltage generation circuit, and 13 is a discharge lamp.

Reference numerals 21 and 31 denote primary windings connected to the DC power supply 2, reference numerals 22 and 32 denote secondary windings for increasing the voltage generated by the primary windings 21, 31, and reference numeral 23 denotes a primary winding 21. The first transformer 33 is composed of a primary winding 31 and a secondary winding 32. The first transformer 33 is composed of a primary winding 31 and a secondary winding 32. The first transformer 41 is applied to the primary winding 21. A first transistor (switching circuit) for turning on / off a voltage to be turned on and a second transistor (switching circuit) for turning on / off a voltage applied to the secondary winding 22.

A first transformer control 51 receives the triangular wave 6a shown in FIG. 2A and the feedback voltage 14a from the feedback circuit 14, and outputs a rectangular wave transistor drive signal 53 shown in FIG. 2B. The circuit 52 receives the triangular wave 6b shown in FIG. 2D and the feedback voltage 14a from the feedback circuit 14, and
Is a second transformer control circuit that outputs a rectangular-wave transistor drive signal 54 shown in FIG. 3A. The triangular wave 6b input to the second transformer control circuit 52 is a triangular wave 6a input to the first transformer control circuit 51. Are shifted by 180 degrees by the inverter 61. 71
Is a smoothing circuit for smoothing the voltage generated in the secondary windings 22, 32.

Next, the operation will be described. Transistor drive signal 5 output from first transformer control circuit 51
3 and the transistor drive signal 54 output from the second transformer control circuit 52 are 180 degrees out of phase. In addition, the first transformer current (see FIG. 2C) 55 generated by the first transformer 23 and the second transformer current (see FIG. 2F) 56 generated by the second transformer 33 also include: The phases are shifted by 180 degrees.

For this reason, the combined current 57 of the first transformer current 55 and the second transformer current 56 is, as shown in FIG. And the phases of the currents flowing through the respective transformers are shifted by 180 degrees, so that the lower limit is increased. Therefore, the power supply current 58 smoothed by the LC filter 9 has a waveform close to DC as shown in FIG. Therefore, the noise component included in the power supply current 58 can also be reduced. Here, since the triangular wave 6b is created by inverting the triangular wave 6a by the inverter 61, the phase shift is 180 degrees, but other phase shifts such as 30 degrees and 60 degrees may be used. However, in the case of a phase shift of 180 degrees, a waveform closest to a straight line is obtained.

As described above, according to the first embodiment, the power supply current 58 has a waveform close to DC and the power supply current 58
Can reduce the noise component contained in the
Effects such as a reduction in radio noise entering the AM band and FM band of a vehicle-mounted radio and noise entering other electronic devices can be obtained. Further, by inverting the phase using an inverter, a phase shift of 180 degrees can be easily created.

Further, two transformers 23 and 33, transistors 41 and 42, and two transformer control circuits 51 and 52 are connected to each other, and the load on each component can be reduced. A smaller one can be used as compared with the case. For this reason, there can be obtained an advantage that the configuration of the entire discharge lamp lighting device can be reduced in size and thickness.

Further, since the switching speed can be increased by using the small transistors 41 and 42,
Switching loss caused by the slow rise of the current of the transistor can be reduced, and effects such as improvement in efficiency can be obtained. Further, since the width of the upper and lower limits of the power supply current is narrowed, the size of the LC filter can be reduced.

[0020]

As described above, according to the present invention, at least two or more transformers, switching circuits, and transformer control circuits are provided, and each of the transformer control circuits outputs a switching circuit control signal having a different phase from each other. Therefore, it is possible to reduce the generation of noise and to reduce the size and thickness of the entire device.

According to the present invention, two transformers, switching circuits, and two transformer control circuits are provided, and the phase of the switching circuit control signal output from one of the transformer control circuits is shifted by 180 degrees. This has the effect of reducing the occurrence and making it possible to easily obtain a configuration for further reducing the size and thickness of the entire device by using an inverter or the like.

[Brief description of the drawings]

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

FIG. 2 is a waveform diagram showing signal waveforms of the discharge lamp lighting device according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a conventional discharge lamp lighting device for use in a vehicle.

FIG. 4 is a waveform chart showing signal waveforms of a conventional discharge lamp lighting device.

[Explanation of symbols]

2 DC power supply, 11 H bridge (discharge voltage supply circuit), 12 high voltage generation circuit, 13 discharge lamp, 21
31 primary winding, 22, 32 secondary winding, 23 first transformer (transformer), 33 second transformer (transformer), 41 first transistor (switching circuit), 42 second transistor (switching) Circuit), 51 first transformer control circuit (transformer control circuit), 52 second transformer control circuit (transformer control circuit), 53, 54 transistor drive signal, 61 inverter.

Claims (2)

[Claims] 1. A primary winding connected to a DC power supply, a transformer for boosting a voltage generated by the primary winding by a secondary winding, and a voltage generated by the transformer via a high voltage generating circuit. A discharge voltage supply circuit for supplying a discharge lamp; a switching circuit for turning on / off a voltage applied to the primary winding; and a transformer control circuit for outputting a switching circuit control signal to the switching circuit. In the lamp lighting device, at least two or more of the transformer, the switching circuit, and the transformer control circuit are provided, and each of the transformer control circuits outputs the switching circuit control signal having a different phase from each other. Discharge lamp lighting device. 2. The method according to claim 1, wherein two transformers, a switching circuit, and two transformer control circuits are provided, and a phase of a switching circuit control signal output from one of the transformer control circuits is shifted by 180 degrees by an inverter. Discharge lamp lighting device.