JPH06260294A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To allow a stable operation and downsize a device by connecting a current regenerative arresting part to at least one of one terminal and the other terminal of the input winding of a transformer, and controlling a switching element and the current regenerative arresting part to apply a voltage to a discharge lamp. CONSTITUTION:When a switching arrester 21 is ON, a current is carried from a DC power source 1 through the input winding 311 of a transformer 3 and a current regenerative arresting part 91. The arresting part 91 is controlled into short-circuit or low impedance state, and a switching element 22 into OFF state. The output winding 313 of the transformer 3 is laid in impedance infinite state and in non-load state since a discharge lamp 5 which is a load is not broken down. Thus, exciting energy is stored in the transformer 3, and at the moment the element 21 is OFF, the exciting energy is applied to the discharge lamp 5, and the discharge lamp 5 is broken down. Thereafter, the impedance of the discharge lamp 5 is lowered, and the lighting is started. After the breakdown, the arresting parts 91, 92 are controlled into short-circuit or low impedance state, the elements 21, 22 are controlled to be alternately ON/OFF, and the discharge lamp 5 is stably lighted.

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 Generally, in order to light a discharge lamp, a high voltage for breaking down between the main electrodes of the discharge lamp and a discharge sustaining voltage for sustaining the discharge are required.

Conventionally, as a discharge lamp lighting device of this type,
The one shown in FIG. 61 is known. In FIG. 61, 1
Is a DC power supply, 7 is a DC-DC converter, 2 is a switching unit, 4 is a high voltage generation circuit, and 5 is a discharge lamp. When the voltage of the DC power supply 1 is applied to the DC-DC converter 7,
As the output voltage of the DC-DC converter 7 rises, power is also supplied to the high voltage generation circuit 4. At this time, the high-voltage generating circuit 4 generates a high-voltage pulse voltage required for breakdown between the main electrodes of the discharge lamp 5 to activate the discharge lamp 5 by the on / off operation of the switch 41 of the high-voltage generating circuit 4, and then discharges it. It is applied to the electric lamp 5.

After the breakdown, the output of the DC-DC converter 7 is switched to the switching unit 2 and the high-voltage generating circuit 2.
A current flows through the secondary winding 422 to the discharge lamp 5 to light it.

FIG. 62 shows another conventional example, in which an LC resonance circuit is used as the high voltage generation circuit 4, the switching frequency of the switching section 2 is controlled, and when the resonance frequency of the LC resonance circuit is reached, resonance occurs to generate a high voltage pulse voltage. . 6 in the figure
Is a DC blocking capacitor.

FIG. 63 is also another conventional example, in which a push-pull inverter circuit using a transformer 3 is used, and DC-DC of FIG.
The converter 7 and the switching unit 2 have a step-up function and a DC-AC conversion function.

[0007]

As described above, lighting the discharge lamp requires a high voltage and a discharge sustaining voltage. However, as in the conventional example, each circuit requires an individual circuit, and each circuit requires each circuit. Inductor parts for boosting are needed.
For this reason, there are many circuit components, and there is a problem in that they are large and expensive.

Further, since the resonance inductor having a large inductance in the high voltage circuit and the secondary winding of the high voltage transformer are connected in series between the discharge lamp and the discharge sustaining voltage circuit output, lighting at a high frequency is performed. In the above, there is a problem in that the current at the time of starting the discharge lamp cannot be secured or the electric power applied to the discharge lamp cannot be secured, so that it is necessary to increase the output voltage of the discharge sustaining voltage circuit or a circuit for reducing the inductance. It was

SUMMARY OF THE INVENTION It is an object of the present invention to provide a discharge lamp lighting device which is small in size, inexpensive, and stable in operation by eliminating the above-mentioned conventional drawbacks.

[0010]

To solve the above problems, the present invention includes a DC power supply, a switching element, a transformer, a current regeneration blocker, a control circuit, and a discharge lamp.
The transformer has two input windings, one end of each of the two input windings is connected to the positive output of the DC power source with different polarities, and the other end is connected through the switching element. Connected to the negative output of the DC power supply, a current regeneration block is connected to at least one of one end and the other end of the two input windings, and the switching element and the current regeneration block are driven by a control circuit. Thus, the high voltage and the AC output voltage are applied to the discharge lamp connected to the output winding.

[0011]

With the above configuration, the impedance of the discharge lamp is infinite when the discharge lamp is not broken down, so the output of the transformer is in a no-load state, and when the switching element is turned on in this state, the input of the transformer is changed. A current flows from the DC power supply to the winding, the excitation energy is stored in the transformer in proportion to the inductance and on-time, and at the moment when the switching element is turned off, the inductance of the transformer is connected to the discharge lamp connected to the transformer output. Also, a high-voltage pulse voltage that resonates at a resonance frequency with the capacity of the transformer and the capacity of the connected circuit is applied, and the discharge lamp breaks down. After breakdown, the impedance of the discharge lamp drops significantly, and current flows through the transformer output winding to maintain discharge. This series of operations is controlled by the control circuit, and finally stable lighting is achieved.

Therefore, an independent circuit as a high voltage generation circuit is not required, the circuit configuration is extremely simple and compact, an inexpensive discharge lamp lighting device can be realized, and the above-mentioned problems in high frequency lighting do not occur. Higher frequency and smaller size can be realized.

[0013]

1 is a circuit diagram of a discharge lamp lighting device according to the present invention. In FIG. 1, the same reference numerals as those in FIG. 63 are components having the same functions. 1 is a DC power supply, 2 is a switching unit, 21 and 22 are switching elements, 23 and 24 are diodes, 3 is a transformer, 311 and 312 are input windings,
313 is an output winding, 91 and 92 are current regeneration blockers, and 8 is a control circuit. The current regeneration blocking units 91 and 92 are portions having a function of blocking regeneration of stored energy of the transformer 3 to the input side when a high voltage output is generated.

When the switching element 21 is turned on, a current flows from the DC power supply 1 through the input winding 311 of the transformer 3 and the current regeneration blocker 91. At this time, the current regeneration blocking unit 9
1 is controlled to be in a short circuit or low impedance state, the current regeneration blocker 92 is controlled to be in an open or high impedance state, and the switching element 22 is controlled to be in an off state. In the output winding 313 of the transformer 3, the discharge lamp 5 as a load is not broken down, so that the impedance is infinite and the load is not applied.

Therefore, the transformer 3 stores the excitation energy ½ LI ^{2 which} is determined by the inductance of the transformer 3 and the current proportional to the ON time. Next, at the moment when the switching element 21 is turned off, the excitation energy stored in the transformer 3 resonates at a resonance frequency with the inductance of the transformer 3 and the capacitance of the transformer 3 and the inductance and capacitance of the connected circuit. High voltage pulse voltage
It is applied to the discharge lamp 5 connected to the output winding 313, and the discharge lamp 5 breaks down.

After the breakdown of the discharge lamp 5, the impedance is remarkably lowered, a current flows from the output winding 313, the discharge is maintained, and the discharge lamp 5 starts lighting. After the breakdown, the current regeneration blocking units 91 and 92 are controlled to be in a short-circuit or low impedance state, the switching elements 21 and 22 are controlled to alternately perform on / off operations, and an alternating voltage is applied to the discharge lamp 5 for stable lighting. maintain.

Therefore, an independent circuit is not required as the high voltage generating circuit, the circuit configuration is extremely simple, and the loss due to the high inductance in the high voltage generating circuit does not occur at the time of high frequency lighting.
An inexpensive discharge lamp lighting device can be realized.

FIG. 2 is a circuit diagram of a specific embodiment of the discharge lamp lighting device according to the present invention. In FIG. 2, the same reference numerals as those in FIG. 1 are components having the same functions. Reference numeral 921 is a variable inductor as the current regeneration blocking unit 92. As the switching elements 21 and 22, bipolar transistors or field effect transistors are used. In the case of a field effect transistor, the diodes 23 and 24 are the internal diodes of each. FIG. 3 is an example of operation waveforms of the embodiment of FIG. FIG. 4 is a characteristic diagram of the variable inductor 921.

The input winding 311 of the transformer 3 is a diode 2
3 is connected to both ends of the DC power supply via a parallel circuit of the switching element 21 and the input winding 312 is connected to the DC power supply 1 via a parallel circuit of the variable inductor 921 and the diode 24 and the switching element 22. There is.

When the switching element 21 is turned on while the discharge lamp 5 is not lit as described above, 1 / 2LI ²
The exciting energy is stored in the transformer 3. When the switching element 21 is turned off, a counter electromotive voltage in the direction shown in the figure is generated in the input windings 311 and 312 due to the accumulated excitation energy. The counter electromotive voltage generated in the input winding 312 is the main winding a of the diode 24 and the variable inductor 921.
It tries to be regenerated to the DC power supply 1 via.

However, in the variable inductor 921, when the current of the control winding b is set to 0 as shown in the characteristic of FIG. 4, the inductance of the main winding a becomes extremely large and becomes high impedance, so that regeneration is blocked. . Therefore, when the switching element 21 is turned on, the energy 1 / 2LI ² accumulated in the transformer 3 can be converted into a high-voltage pulse voltage generated in the output winding 313 without being regenerated, and a high voltage is generated.

Although the switching element 22 is off during the high voltage generation period, when the discharge lamp 5 breaks down due to the high voltage pulse voltage, the control circuit 8 alternately turns on and off the switching elements 21 and 22. Is controlled so that At the same time, the variable inductor 921 is controlled so that a current flows through the control winding b, the inductance becomes extremely low and the impedance becomes low, and the variable inductor 921 is started and stably lit.

When the discharge lamp 5 is a high-intensity discharge lamp such as a metal halide lamp, in order to accelerate the rising of light,
It is necessary to quickly vaporize the metal halide enclosed in the discharge lamp. Therefore, the discharge current of the discharge lamp 5 after breakdown is increased to several times that during stable lighting, and the temperature rise time inside the tube is shortened. The control circuit 8 detects the current or the voltage of the discharge lamp 5 or both of them, and changes the ON time of the switching elements 21 and 22 to perform pulse width control for controlling the electric power applied to the discharge lamp 5 to emit light. The pulse width is expanded and the current is increased during the startup period.

It is generally said that a metal halide lamp goes out when a current rest period exists, but in a 35W metal halide lamp for a vehicle headlight, a lamp applied current waveform in a lighting frequency range of 20 kHz to 50 kHz,
When confirmed with a rectangular wave, the result shown in FIG. 5 is obtained, and even if there is a current quiescent period, it is stably turned on without extinguishing under a certain on-duty condition. For example, at a lighting frequency of 20 kHz, it is possible to light with a pulse current with an on-duty of 40% to 100%.

Therefore, an independent circuit is not required as the high-voltage generating circuit, the circuit configuration is extremely simple, and the loss due to the high inductance in the high-voltage generating circuit does not occur at the time of high frequency lighting. A lighting device can be realized.

Further, since most of the counter electromotive voltage generated in the input winding 312 when the switching element 21 is turned off is applied to the main winding a of the variable inductor 921, a low breakdown voltage element can be used as the switching element 22 and it is inexpensive. become. or,
In the case of a field effect transistor, the on resistance is also reduced, so the loss is reduced and the efficiency is increased.

FIG. 6 shows an example of operation waveforms when the push-pull operation is performed by the switching elements 21 and 22 even in the high voltage generation period in the embodiment of FIG.

Switching element 2 in the high voltage generation period
1 and 22 alternately perform on / off operation. The operation when the switching element 21 is turned on / off is the same as described above. The current flowing when the switching element 22 is turned on is extremely small compared to the current when the switching element 21 is turned on because of the variable inductor 921 in the high inductance state. Therefore, the energy stored in the transformer 3 is small, and when the switching element 22 is turned off, no voltage is generated in the output winding 313 as much as when the switching element 21 is turned off. The operation of the discharge lamp 5 after breakdown is exactly the same as described above.

There is no need to change the control operation during the high voltage generation period and the start and stable lighting periods, and the control circuit 8 becomes simple and inexpensive.

FIG. 7 is a circuit diagram of a discharge lamp lighting device according to a second embodiment of the present invention. In FIG. 7, the same reference numerals as those in FIG. 2 are components having the same functions. 911
Is the same variable inductor as 921 and the current regeneration blocker 91
Is used as. FIG. 8 is an operation waveform example of the embodiment of FIG.

The input winding 311 of the transformer 3 includes a variable inductor 911, a switching element 21 and a diode 23.
The input winding 312 is connected to the DC power source 1 via a parallel circuit of the variable inductor 921 and the switching element 22 and the diode 24.
By the push-pull operation control in which the switching elements 21 and 22 are alternately turned on and off, during the high voltage generation period, the switching element 22 is off when the switching element 21 is on,
The variable inductor 911 has a low inductance, the variable inductor 921 has a high inductance, and the switching element 22.
Is ON, the switching element 21 is OFF, the variable inductor 921 has low inductance, and the variable inductor 91
1 is a discharge lamp 5 by controlling to high inductance
A positive and negative high voltage pulse voltage is applied to.

Therefore, if the number of high-voltage pulse voltages applied to the discharge lamp 5 is the same, the switching elements 21, 22 are
Are alternately turned on, the loss of the switching elements 21 and 22 is halved as compared with the embodiment of FIG. 2, the temperature rise is reduced and the reliability is improved. In addition, the switching element 21,
Both 22 can use an element having a low withstand voltage and are inexpensive. On the other hand, in the case of a field effect transistor, the on resistance becomes small and the efficiency further increases.

FIG. 9 shows a third embodiment of the discharge lamp lighting device according to the present invention.
3 is a circuit diagram in the embodiment of FIG. In FIG. 9, the same reference numerals as those in FIG. 2 are components having the same functions. FIG. 10 is an example of operation waveforms of the embodiment of FIG.

The input winding 311 of the transformer 3 is connected via a parallel circuit of the switching element 21 and the diode 23, and the input winding 312 is connected via a parallel circuit of the switching element 22 and the diode 24 to the DC power source 1 and the variable inductor. 921
And are connected to both ends of the series circuit. The push-pull operation is controlled such that the switching elements 21 and 22 are alternately turned on and off, and the variable inductor 921 has a low inductance when any one of the switching elements 21 and 22 is on during the high voltage generation period, and has a high inductance otherwise. By controlling so that the positive and negative high voltage pulse voltages are applied to the discharge lamp 5.

Therefore, one variable inductor can be reduced to obtain the same high-voltage pulse voltage as compared with the embodiment of FIG.
Inexpensive and small.

FIG. 11 is a circuit diagram of a discharge lamp lighting device according to a fourth embodiment of the present invention. 11, the same reference numerals as those in FIG. 2 are components having the same functions. Two
Reference numerals 5 and 26 are capacitors. FIG. 12 shows an operation waveform example of the embodiment shown in FIG.

The input winding 311 of the transformer 3 is connected to both ends of the DC power source 1 through a parallel circuit of the switching element 21, the diode 23 and the capacitor 25, and
12 is the variable inductor 921 and the switching element 22.
Is connected to the DC power supply 1 through a parallel circuit of the diode 24 and the capacitor 26. When the switching element 21 is turned on while the discharge lamp 5 is not lit, the excitation energy is stored in the transformer 3, and when it is turned off, the input winding 3 is turned on.
A counter electromotive voltage is generated in 11, 312, and the counter electromotive voltage generated in the input winding 312 is blocked by the high inductance of the variable inductor 921, so that energy is not regenerated in the DC power supply 1.

The stored energy resonates at the resonance frequency of the inductance and capacitance components of the transformer 3 and the capacitor 25 connected in parallel with the switching element 21, and a high voltage pulse voltage having a low voltage peak value but a wide time width is generated. It is applied to the discharge lamp 5. When the discharge lamp 5 breaks down, the control circuit 8 controls the variable inductor 921 to have a low inductance and the switching elements 21 and 22 to alternately turn on and off to perform a push-pull operation.

When the switching element 21 is on, a current I ₂₁ flows through the input winding 311 and energy is stored in the leakage inductance of the input winding 311. When the switching element 21 is turned off, the energy stored in the leakage inductance causes the leakage inductance and the capacitor 2
A resonance current with 5 flows. Since the variable inductor 921 has a low inductance, the same current I ₂₂ flows through the input winding 312, the variable inductor 921, and the switching element 22 as well. An AC voltage waveform close to a sine wave is generated in the output winding 313 and is applied to the discharge lamp 5. The electric power of the discharge lamp 5 is controlled by detecting the voltage and / or current of the discharge lamp 5 and changing the ON time of the switching elements 21 and 22.

The same control can be performed by adding an inductor instead of the leakage inductance as the resonance inductor.

FIG. 13 is a circuit diagram of a discharge lamp lighting device according to a fifth embodiment of the present invention. In FIG. 13, the same reference numerals as those in FIG. 11 are components having the same functions.
27 and 28 are switches. FIG. 14 shows an operation waveform example of the embodiment shown in FIG.

In the embodiment of FIG. 13, the high voltage pulse voltage is the inductance, capacitance component and capacitor 25 of the transformer 3.
Since it resonates at the resonance frequency with, the high-voltage pulse voltage has a wide time width but a low voltage peak value.
Is connected in series with the switch 27, and the switch 28 is connected in series with the capacitor 26.
28 is turned off and the discharge lamp 5 is turned on after the breakdown, so that the capacitors 25, 26 are turned on during the high voltage generation period.
It is made to generate the high voltage pulse voltage of a higher voltage value by making it resonate at the resonance frequency of the inductance of the transformer 3, the capacitance component, and the capacitance of the connected circuits other than the capacitors 25 and 26 without being affected by It is a thing. The switches 27 and 28 can be used with or without contacts such as relays and switches, or without contacts such as semiconductors.

FIG. 15 shows an example of operation waveforms when the push-full operation is performed during the high voltage generation period in the embodiment of FIG. 13, and the control operation is the same control operation during the high voltage generation period, the starting period, and the stable lighting period. Therefore, the control circuit 8 becomes simple and inexpensive.

FIG. 16 is a circuit diagram of a discharge lamp lighting device according to a sixth embodiment of the present invention. In FIG. 16, the same reference numerals as those in FIG. 13 are components having the same functions.
Reference numeral 911 is a variable inductor as the current regeneration blocker 91. FIG. 17 shows an example of operation waveforms in the embodiment of FIG.

Using variable inductors 911 and 921,
During the high voltage generation period, the switches 27 and 28 are turned off and the switching elements 21 and 22 are made to push-pull. At this time, the variable inductor 911 is the switching element 21,
The variable inductor 921 is controlled so as to have a low inductance when the switching elements 22 are on, and a high inductance when the switching elements 22 are on.
A high-voltage pulse voltage of both positive and negative polarities can be applied to the discharge lamp 5 connected to.

By using the two variable inductors 911, 921, the switching element 21,
The loss of 22 is reduced to half and the switching elements 21,
Since the temperature rise of 22 is reduced, the reliability is improved. Moreover, since the voltage generated in the input windings 311 and 312 during the high voltage generation period is applied to the variable inductors 911 and 921, low withstand voltage elements can be used as the switching elements 21 and 22 and the cost is reduced. Further, in the case of a field effect transistor, the lower the breakdown voltage, the smaller the on-resistance and the higher the efficiency.

Moreover, an independent circuit is not required as a high-voltage generating circuit, and the circuit configuration is extremely simple. Further, since loss due to high inductance in the high-voltage generating circuit does not occur during high-frequency lighting, the frequency can be increased and the size can be reduced. A lighting device can be realized.

FIG. 18 is a circuit diagram of a discharge lamp lighting device according to a seventh embodiment of the present invention. 2 in FIG.
The same reference numerals as are the components having the same function. 92
Reference numeral 2 is a switch as the current regeneration blocker 92. During the high voltage generation period, the switch 922 is turned off, the switching element 21 is turned on / off, and the high voltage pulse voltage is generated in the discharge lamp 5. Since the switch 922 completely disconnects the current regeneration path, there is no regeneration of the energy stored for the generation of high voltage, and a higher high-voltage pulse voltage can be generated. The switch 922 may be a contact such as a relay or a switch, or a non-contact such as a semiconductor.

FIG. 19 is a circuit diagram of the discharge lamp lighting device according to the eighth embodiment of the present invention. In FIG. 19, the same reference numerals as those in FIG. 18 are components having the same functions.
Reference numeral 912 is a switch as the current regeneration blocker 91.
FIG. 20 is an example of operation waveforms of the embodiment of FIG.

When the switching element 21 is on during the high voltage generation period, the switch 912 is turned on, the switch 922 is turned off,
When the switching element 22 is on, the switch 912 is turned off and the switch 922 is turned on to generate a high-voltage pulse voltage of both positive and negative polarities, and the switch 912 is turned on during the starting and stable lighting periods.
Both 922 are turned on and an AC voltage is applied to the discharge lamp 5.

A switch 912 is provided as a current regeneration blocking circuit.
By using 922, compared with the case of using the variable inductor, the regeneration of the current is completely blocked, so that all the stored energy becomes the high voltage pulse voltage on the secondary side and a high peak value is obtained. Also, the shape is small. Moreover, an independent circuit is not required as a high-voltage generating circuit, and the circuit configuration is extremely simple. Also, because high-frequency lighting does not cause loss due to high inductance in the high-voltage generating circuit, higher frequencies can be achieved, and a compact and inexpensive discharge lamp lighting device is realized. it can.

21 and 22 are circuit diagrams of the discharge lamp lighting device according to the ninth and tenth embodiments of the present invention. 21 and 22, the same reference numerals as those in FIG. 13 are components having the same functions. Reference numerals 912 and 922 are switches as the current regeneration blocking units 91 and 92. FIG. 23 is an example of operation waveforms of the embodiment of FIG. The operation and effect are the same as in the case of FIGS.

24 and 25 are circuit diagrams in the eleventh and twelfth embodiments of the discharge lamp lighting device according to the second aspect of the present invention. 24 and 25, the same reference numerals as those in FIG. 7 are components having the same functions. 29 and 30 are switches. FIG. 26 is an example of operation waveforms of the embodiment of FIG.

During the high voltage generation period, the switching elements 21, 2
2 is off, and the variable inductors 911 and 921 are controlled to a high impedance state. When the switch 29 is turned on, a current flows through the input winding 311 and energy is stored in the transformer 3. When the switch 29 is turned off, the input winding 3
A counter electromotive voltage is generated in 11, 312, and the counter electromotive voltage generated in the input winding 312 tries to be regenerated to the input DC power supply 1. However, since the variable inductor 921 has a high impedance, it is not regenerated and is accumulated. Most of the energy is released as a high voltage pulse voltage in the output winding 313.

Output winding 3 when switch 30 is turned on and off
A high voltage pulse voltage having a polarity opposite to the polarity when the switch 29 is turned on and off is generated at 13. Variable inductor 911,
Input windings 311 and 3 due to the high impedance of 921.
The voltage generated in 12 is applied to the variable inductors 911 and 921, but is hardly applied to the switching elements 21 and 22. After the discharge lamp 5 breaks down, the switches 29 and 30 are off, the variable inductors 911 and 921 are in a low impedance state, and the switching elements 21 and
2 starts with push-pull operation for pulse width control,
Stable lighting.

By providing the switches 29 and 30 for generating high voltage, a large current for generating high voltage is generated by the switch 2.
9 and 30, and the switching elements 21 and 22 can be made to flow only a small current during a stable lighting during the starting period.
The switching elements 21 and 22 having a low withstand voltage and a small current capacity can be used, and the cost is low. The switches 29 and 30 may be either a contact such as a relay or a switch or a non-contact such as a semiconductor.

27 and 28 are circuit diagrams in the thirteenth and fourteenth embodiments of the discharge lamp lighting device according to the second aspect of the present invention. 27 and 28, the same reference numerals as those in FIG. 13 are components having the same functions. 29 and 30 are switches. FIG. 29 shows an example of operation waveforms of the embodiment shown in FIG.

By providing the switches 29 and 30 for generating high voltage, a large current does not flow through the switching elements 21 and 22 when high voltage is generated. Moreover, the variable inductor 911,
Since 921 has high impedance,
When a high voltage is generated as in the embodiment of FIG. 16, the switches 27, 2
8 can be used to generate a high voltage pulse voltage at the same level as in the embodiment of FIGS. 13 and 16 without disconnecting the capacitors 25 and 26. Therefore, it is possible to use the switching elements 21 and 22 having low withstand voltage and small capacity, and the switches 27 and 28 of the embodiments of FIGS. 13 and 16 are not required, so that the cost is low and the efficiency is greatly improved.

FIG. 30 is a circuit diagram of the fifteenth embodiment of the discharge lamp lighting device according to the second aspect of the present invention. Figure 3
27, the same reference numerals as those in FIG. 27 are components having the same functions. FIG. 31 shows an example of operation waveforms of the embodiment shown in FIG. Switching element 21 is off, variable inductor 91
When 1 is in a high impedance state, a high voltage pulse voltage that resonates with the inductance of the transformer 3, the capacitance component, and the capacitance of the connected circuit is generated in the output winding 313 when the switch 29 is turned on and off. After the discharge lamp 5 breaks down, the switch 29 is turned off, the variable inductor 911 is in a low impedance state, and an output voltage proportional to the current flowing through the input winding 311 is generated by turning on / off the switching element 21.

In this way, one input winding 311, variable inductor 911, switching element 21, switch 29 are provided.
Thus, the primary side can be configured, the number of parts can be greatly reduced, and it is inexpensive and compact.

32 and 33 are circuit diagrams in the sixteenth and seventeenth embodiments of the discharge lamp lighting device according to the second aspect of the present invention. 32 and 33, the same reference numerals as those in FIG. 28 are components having the same functions. 913,92
Reference numeral 3 is a saturable reactor as the current regeneration blocking units 91 and 92. FIG. 36 shows an example of operation waveforms of the embodiment shown in FIG.

The saturable reactors 913 and 923 use the core having the magnetization characteristic having the rectangular hysteresis as shown in FIG. 34, so that the inductance becomes the inductor having the DC superposition characteristic as shown in FIG. When the current hardly flows, it has high inductance, and when it flows a little, it has low inductance.

In the embodiment of FIG. 32, the variable inductors 911 and 921 are replaced with those of the saturable reactor 91 in the embodiment of FIG.
It is replaced with 3,923. The operation is the same as that of the embodiment shown in FIG.

In the embodiment of FIG. 33, the variable inductors 911 and 921 in the embodiment of FIG.
It is replaced with 3,923. The operation is the same as that of the embodiment shown in FIG.

Therefore, the control current in the variable inductor is unnecessary and the control is simplified. Moreover, the efficiency is increased, and it is cheap and compact.

The saturable reactors 913 and 923 can be used in all the embodiments using the variable inductor. Further, fixed inductors can be used as the current regeneration blocking units 91 and 92 depending on conditions.

FIG. 37 is a circuit diagram of an eighteenth embodiment of the discharge lamp lighting device according to the third aspect of the present invention. Figure 3
In FIG. 7, the same reference numerals as those in FIG. 7 are components having the same functions. Reference numeral 314 is a high voltage drive winding, and 301 is a switch. FIG. 39 shows an example of operation waveforms of the embodiment shown in FIG.

High-voltage drive winding 31 provided in the transformer 3.
4 is connected to the DC power supply 1 via the switch 301. In the transformer 3, the high voltage driving winding 314 has an input winding 31.
A winding structure in which the coupling between the input windings 311 and 312 and the output winding 313 is close to each other and the output winding 313 is close to each other. Have. For example, the structure is as shown in FIGS. 41 and 42.

Accordingly, when the switch 301 is turned on, the transformer 3
Due to the excitation energy stored in, the counter electromotive voltage generated in the input windings 311 and 312 when the switch 301 is off and the variable inductors 911 and 921 have high impedance, almost all the stored energy is regenerated. It can be taken out as a high-voltage pulse voltage of the output winding 313 without any need. In addition, by using separate windings, the turn ratio of the high voltage driving winding 314 and the output winding 313 during high voltage pulse voltage output, and the input windings 311 and 312 and the output winding during stable lighting AC output It is possible to separately adjust the winding ratio with respect to 313. Further, the switching elements 21 and 22 may have low withstand voltage and small capacity.
The switch 301 may be a contact such as a relay or a switch or a non-contact such as a semiconductor.

Moreover, an independent circuit is not required as the high-voltage generating circuit, the circuit configuration is extremely simple, and since loss due to the high inductance in the high-voltage generating circuit does not occur during high-frequency lighting, the frequency can be made higher, and the size is small and inexpensive. An electric lamp lighting device can be realized.

FIG. 38 is a circuit diagram of a discharge lamp lighting device according to a nineteenth embodiment of the present invention. Figure 3
In FIG. 8, the same reference numerals as those in FIG. 14 are components having the same functions. Reference numeral 314 is a high voltage drive winding, and 301 is a switch. FIG. 40 shows an example of operation waveforms of the embodiment shown in FIG. The operation and effect are similar to those in the case of FIG.

FIG. 43 is a circuit diagram of a twentieth embodiment of the discharge lamp lighting device according to the fourth aspect of the present invention. Figure 4
In FIG. 3, the same reference numerals as those in FIG. 37 are components having the same functions. 302 is a diode, 303 is a capacitor, and 10 is an insulation drive circuit for the switch 301. Figure 4
5 is an example of an operation waveform when the high voltage is generated in the embodiment of FIG.

The high voltage drive winding 314 is connected to the switch 301.
A parallel circuit of the diode 302 and the capacitor 302 and the capacitor 303 form a closed circuit, and this closed circuit is insulated from other circuits. The switch 301 is controlled by the control circuit 8 via the insulation drive circuit 10. The push-pull operation by the switching elements 21 and 22 is performed while the discharge lamp 5 is not lit.

At this time, the variable inductors 911 and 921 are in a low impedance state and the switch 301 is off.
In the high voltage drive winding 314, a pulse voltage having a winding ratio times that of the input windings 311 and 312 is generated, rectified and smoothed by the diode 302 and the capacitor 303, and a DC voltage can be obtained in the capacitor 303. If the turn ratio between the input windings 311 and 312 and the high-voltage driving winding 314 is set to 1 or more, a voltage higher than the input DC voltage can be obtained. After that, the switching elements 21 and 22 are turned off, and the variable inductor 9
Switch 11 and 921 to high impedance state and switch 3
By turning ON / OFF 01 through the insulation driving circuit 10, a high-voltage pulse voltage having a higher peak value is applied to the discharge lamp 5.

A large exciting current or a large resonant current flows in the high voltage drive circuit, and a high resonant voltage is generated, which often causes a malfunction of the control circuit 8 which handles a minute signal. In this circuit, since the high voltage drive circuit is completely insulated, it is possible to realize the control circuit 8 which is less likely to malfunction. Switch 3
When a field effect transistor is used for 01, a built-in diode can be used as the diode 302. The insulation drive circuit 10 can be configured by a relay, a transformer, a photocoupler, or the like.

FIG. 44 is a circuit diagram of the twenty-first embodiment of the discharge lamp lighting device according to the fourth aspect of the present invention. Figure 4
4, the same reference numerals as those in FIG. 38 are components having the same functions. 302 is a diode, 303 is a capacitor, and 10 is an insulation drive circuit for the switch 301. The operation and effect are similar to those of the embodiment shown in FIG.

46 and 47 are circuit diagrams in the twenty-second and twenty-third embodiments of the discharge lamp lighting device according to the fourth aspect of the present invention. 46 and 47, the same reference numerals as those in FIG. 44 are components having the same functions. 304 is a diode. 48 shows an example of operation waveforms during the high voltage generation period of the embodiment of FIG.

In the embodiment shown in FIG. 43, the voltage V _{c of the} capacitor 303 is reduced because energy is discharged when the switch 301 is turned on, and the high voltage pulse voltage is reduced in proportion to the voltage of the capacitor 303. Between the connection point between one end of the high-voltage drive winding 314 and the capacitor 303 and the positive output of the DC power supply 1, the diode 3 is provided with the anode as the DC power supply 1 side.
By connecting 04, the minimum voltage of the capacitor 303 can be ensured up to the voltage of the DC power supply 1, and it is possible to continuously generate a high-voltage pulse voltage equal to or higher than the high-voltage pulse voltage value required for breakdown of the discharge lamp 5. Become.

FIG. 49 shows an embodiment of the transformer 3 used in the discharge lamp lighting device according to claim 5 of the present invention. 11 is EE
Type core, 12 are input and output windings, 13 is a bobbin, l ₁ ,
l ₂ and l are voids.

FIGS. 49 (a) and 49 (b) show a structure in which voids l ₁ and l ₂ are provided in the middle leg of the EE type core 11, and the cross section having the void l ₁ is saturated with the magnetic flux generated by the current I _1. However, the cross section having the air gap l ₂ is saturated with the magnetic flux generated by the current I ₂ .
It has a DC superposition characteristic such as. In the case of the discharge lamp lighting device of the present invention, the flyback operation is basically used for the generation of high voltage, and the push-pull operation is used for the lighting period. In order to increase the energy 1 / 2LI ² stored in the transformer for the generation of high voltage at the same on-time, it is effective to lower the inductance and increase the current.

However, in the push-pull operation at the time of lighting, when the inductance of the transformer 3 is low, the exciting current component of the transformer 3 which is not involved in the output supply increases, resulting in loss of switching elements and copper loss of the transformer. Increase and the efficiency of the device decreases.

FIGS. 51 (a) and 51 (b) show the primary current I ₂₁ when the conventional transformer is used in the circuit of the embodiment of FIG.
2 is a waveform of a primary current I ₂₁ when a transformer having the structure and characteristics of the present invention is used. When the transformer having the structure and characteristics of the present invention is used, the inductance becomes small when the primary current during the high voltage generation period is large, so that the exciting current becomes large and the inductance becomes large when the primary current during the lighting period is small. The excitation current becomes extremely small and the primary current peak value drops. Therefore, since the loss of the switching element and the copper loss of the transformer are reduced, the efficiency of the device is increased and the size can be reduced.

FIG. 52 is a circuit diagram of the twenty fourth embodiment of the discharge lamp lighting device according to the sixth aspect of the present invention. Figure 5
2, the same reference numerals as those in FIG. 2 are components having the same functions. Reference numeral 8a is a portion that detects the power supply voltage in the control circuit during the high voltage generation period and controls the ON time of the switching element 21. 53 is a diagram showing an example of the relationship between the power supply voltage and the gate on time, and FIG. 54 is an example of operation waveforms during the high voltage generation period of the embodiment of FIG.

The present invention according to claims 1 to 5 is a conventional example,
Since the power supply voltage to be the input of the high voltage generation circuit is not controlled to be constant as in FIGS. 61 and 62, when the voltage of the DC power supply 1 as the input changes, the high voltage pulse voltage of the output also largely changes. Therefore, when the voltage of the DC power supply 1 increases, the high-voltage pulse voltage generated in the output winding 313 also increases, and the insulation structure becomes complicated or large. Further, the exciting current flowing through the transformer 3 becomes large during the high voltage generation period, and it is necessary to make the transformer 3 large in order to prevent the transformer 3 from being saturated by this current.

In this case, the output voltage is generally detected and controlled. However, in the case of the invention described in claims 1 to 5, the output voltage is a high-voltage pulse voltage, and the discharge lamp 5 serving as a load is not broken down. Since the impedance is infinite,
The impedance of the detection circuit needs to be larger than the impedance of the discharge lamp 5, and it is also necessary to use high voltage components, which is large and expensive. In addition, the high-voltage pulse voltage may decrease due to the impedance of the detection circuit.

The present invention solves the above problems by detecting the voltage of the DC power supply 1 and changing the ON time of the switching element to make the high-voltage pulse voltage that keeps the current flowing through the transformer constant. is there.

The stored energy for generating high voltage is 1/2
LI ² and the exciting current flowing through the transformer is V _IN · t _ON /
It is determined by L (t _ON is the time when current flows through the transformer 3). When the voltage V _IN of the DC power supply 1 increases, the current flowing through the transformer 3 increases, and the stored energy becomes 1 / 2LI ²
Becomes higher and the high voltage pulse voltage becomes higher. Therefore, by controlling the on-time of the switching element 21 according to the voltage of the DC power supply 1 so that V _IN · t _ON = constant, the current flowing through the transformer 3 becomes constant, and the energy stored in the transformer 3 becomes constant. Becomes constant, the high-voltage pulse voltage becomes constant.

According to the present invention, even if the voltage of the DC power supply 1 changes, the exciting current flowing in the transformer 3 becomes constant and the high-voltage pulse voltage becomes constant, so that the transformer 3 can be downsized and the insulating structure can be simplified. Further, since it is not necessary to detect the output, a high withstand voltage component is not required, the device is small and inexpensive, and the high voltage pulse voltage is not reduced by the detection circuit.

FIG. 55 is a circuit diagram of the twenty-fifth embodiment of the discharge lamp lighting device according to the seventh aspect of the present invention. Figure 5
5, the same reference numerals as those in FIG. 2 are components having the same functions. Reference numeral 8b is a portion that detects the power supply voltage in the control circuit 8 during the high voltage generation period and controls the control winding current of the variable inductor 921. FIG. 56 is a characteristic diagram of the control winding current and the main winding inductance of the variable inductor 921.
FIG. 57 shows an example of operation waveforms during the high voltage generation period of the embodiment of FIG.

The present invention according to claims 1 to 5 provides the invention according to claim 6.
There is a problem as described in the embodiment of. The present invention detects the voltage of the DC power supply 1 and changes the inductance of the variable inductor to control the amount of energy stored in the transformer to be regenerated to the DC power supply 1 when a high voltage is generated, thereby keeping the high voltage pulse voltage constant. The above problems are solved.

When the voltage of the DC power supply 1 is increased without changing the ON time of the switching element 21, the exciting current increases, the accumulated energy of the transformer 3 increases, and the high voltage pulse voltage also increases.

Therefore, the inductance of the variable inductor 921 becomes smaller as the voltage of the DC power supply 1 becomes higher, so that the control winding current I ₃ causes L to fall at the lowest voltage (0.9V _IN ) as shown in FIG. 56, for example. _{1. The} high-voltage pulse voltage generated in the output winding 313 is generated by making the DC power source 1 regenerate the excess accumulated energy as the current I ₂₂ when the high voltage is generated by reducing the L ₂ and L ₃ as the voltage increases. Control.

In the embodiment of FIG. 52 of claim 6, the ON time of the switching element 21 is controlled. However, when the voltage fluctuation range of the DC power supply 1 is large, the ON time becomes short when a high voltage is input, and the accuracy is high. A pulse oscillation circuit may be needed.

In the present invention, the on-time is not changed because it is not changed. Further, the insulating structure is simple, and since it is not necessary to detect the output, high withstand voltage parts are not required, and the device is small and inexpensive, and the detection circuit does not lower the high voltage pulse voltage.

FIG. 58 is a circuit diagram of a twenty-sixth embodiment of the discharge lamp lighting device according to the seventh aspect of the present invention. Figure 5
8, the same reference numerals as those in FIG. 16 are components having the same functions. Reference numeral 8c is a portion that detects the power supply voltage in the control circuit 8 during the high voltage generation period and controls the control winding current of the variable inductors 911 and 921. FIG. 59 is a characteristic diagram of the control winding current and the main winding inductance of the variable inductors 911 and 921. FIG. 60 shows an example of operation waveforms during the high voltage generation period in the embodiment of FIG.

In order to control the high-voltage pulse voltage, the ON time of the switching element is controlled in the embodiment shown in FIG. 52. However, when the voltage fluctuation width of the DC power supply 1 is large, the ON time becomes short at the time of high voltage input and the accuracy is high. High pulse oscillation circuit is required. Further, in the embodiment of FIG. 55, the inductance of the variable inductor 921 which is the current regeneration blocking unit 92 for generating high voltage is changed to control the amount of energy regeneration, but the exciting current flowing through the transformer 3 is the voltage of the DC power supply. There is a problem in that the transformer 3 becomes large as the size increases.

In this embodiment, the variable inductors 911 and 9 are
By changing the inductance of the transformer 21, the exciting current of the transformer 3 is made constant, and the stored energy in the transformer 3 is made constant, so that the high-voltage pulse voltage is controlled and the above-mentioned problems are solved.

The operation is the same as that of the embodiment of FIG. 16, the switches 27 and 28 are off during the high voltage generation period, and the switching elements 21 and 22 perform push-pull operation. The variable inductor 911 has a low inductance when the switching element 21 is on, and has a high inductance when the switching element 21 is on. The variable inductor 921 has a low inductance when the switching element 22 is on, and has a high inductance when the switching element 22 is otherwise on. It is controlled by ₃ and I ₄ . When the switching elements 21 and 22 are on, the exciting current I is applied to the transformer 3.
_{Although the} currents ₂₁ and I ₂₂ flow, the exciting currents I ₂₁ and I ₂₂ are determined by the inductances of the input windings 311 and 312 of the transformer and the inductances of the variable inductors 911 and 921.

The exciting current is determined by V _IN · t _ON / L + L _b L: input winding inductance of the transformer L _b : inductance of the variable inductor at V _IN t _ON : time of current flowing through the transformer.

When the voltage V _IN of the DC power supply 1 rises, the exciting current increases when the ON time of the switching element 21 is constant.

Therefore, as shown in FIG. 59, the variable inductor 91
The control winding current I _{4 of 1} is decreased to raise the inductance of the variable inductor to L _a and the exciting current is made constant. On the contrary, when the voltage of the DC power supply 1 is lowered, the inductance of the variable inductor is lowered to make the exciting current constant. Therefore, the energy stored in the transformer 3 becomes constant regardless of the voltage fluctuation of the DC power supply 1, and the high-voltage pulse voltage generated in the output winding 313 is controlled to be constant.

Therefore, the transformer 3 can be downsized, and the high-voltage pulse voltage does not unnecessarily increase, so that the insulating structure is simplified. Further, since it is not necessary to detect the output, a high withstand voltage component is not required, the size is small and the cost is low, and the high voltage pulse voltage is not reduced by the detection circuit.

In the present embodiment, the control by the variable inductor with respect to the voltage fluctuation of the DC power supply 1 can be applied to the starting and stable lighting periods, and the ON time width of the switching element can be reduced to achieve stable control.

[0104]

As described above, the discharge lamp lighting device according to the present invention includes a DC power supply, a switching element, a transformer, a current regeneration blocker, a control circuit, and a discharge lamp.
The transformer has two input windings, one end of each of the two input windings is connected to the positive output of the current power supply with different polarities, and the other end is connected to the negative output of the DC power supply via the switching element. The current regeneration block is connected to at least one of the two ends of the input winding connected to the output, and the switching element and the current regeneration block are controlled to control the discharge connected to the output winding. Since a high voltage and an AC voltage are applied to the lamp, an independent circuit as a high voltage generation circuit is unnecessary, the circuit configuration is extremely simple, and loss due to high inductance in the high voltage generation circuit does not occur during high frequency lighting. It is possible to provide an inexpensive discharge lamp lighting device that can be made higher in frequency and becomes smaller in size.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a discharge lamp lighting device of the present invention.

FIG. 2 is a circuit diagram showing a specific circuit example of the discharge lamp lighting device.

FIG. 3 is an operation waveform diagram of FIG.

FIG. 4 is a characteristic diagram of the variable inductor.

FIG. 5 is a characteristic diagram showing an on-duty that can be turned on for a 35W metal halide lamp for a vehicle headlight.

FIG. 6 is an operation waveform diagram of FIG.

FIG. 7 is a circuit diagram of the second embodiment.

8 is an operation waveform diagram of FIG.

FIG. 9 is a circuit diagram of the third embodiment.

FIG. 10 is an operation waveform diagram of FIG. 9.

FIG. 11 is a circuit diagram of the fourth embodiment.

FIG. 12 is an operation waveform diagram of FIG. 11.

FIG. 13 is a circuit diagram of the fifth embodiment.

14 is an operation waveform diagram of FIG.

FIG. 15 is an operation waveform diagram of FIG.

FIG. 16 is a circuit diagram of the sixth embodiment.

FIG. 17 is an operation waveform diagram of FIG. 16.

FIG. 18 is a circuit diagram of the seventh embodiment.

FIG. 19 is a circuit diagram of the eighth embodiment.

FIG. 20 is an operation waveform diagram of FIG.

FIG. 21 is a circuit diagram of the ninth embodiment.

FIG. 22 is a circuit diagram of the tenth embodiment.

FIG. 23 is an operation waveform diagram of FIG. 22.

FIG. 24 is a circuit diagram of the eleventh embodiment.

FIG. 25 is a circuit diagram of the 12th embodiment.

FIG. 26 is an operation waveform diagram of FIG. 25.

FIG. 27 is a circuit diagram of the thirteenth embodiment.

FIG. 28 is a circuit diagram of the fourteenth embodiment.

FIG. 29 is an operation waveform diagram of FIG. 28.

FIG. 30 is a circuit diagram of the fifteenth embodiment.

FIG. 31 is an operation waveform diagram of FIG. 30.

FIG. 32 is a circuit diagram of the sixteenth embodiment.

FIG. 33 is a circuit diagram of the seventeenth embodiment.

FIG. 34 is a characteristic diagram of the core of the saturable reactor used in the example.

FIG. 35 is a DC superposition characteristic diagram of the saturable reactor.

FIG. 36 is an operation waveform diagram of FIG. 33.

FIG. 37 is a circuit diagram of the eighteenth embodiment.

FIG. 38 is a circuit diagram of the nineteenth embodiment.

FIG. 39 is an operation waveform diagram of FIG. 37.

FIG. 40 is an operation waveform diagram of FIG. 38.

FIG. 41 is a schematic cross-sectional view of the essential parts showing the configuration of the transformer used in the present invention.

FIG. 42 is a schematic cross-sectional view of a main part showing another example of the transformer.

FIG. 43 is a circuit diagram showing the twentieth embodiment.

FIG. 44 is a circuit diagram showing the twenty-first embodiment.

FIG. 45 is an operation waveform diagram of FIG. 43.

FIG. 46 is a circuit diagram showing a twenty-second embodiment.

FIG. 47 is a circuit diagram showing a twenty-third embodiment.

FIG. 48 is an operation waveform diagram of FIG. 46.

49 (a) and (b) are sectional views of a transformer used in the same embodiment.

FIG. 50: DC superimposition characteristic diagram of the same transformer

51 (a) and (b) are primary current waveform diagrams when the transformers of the related art and the present invention are used in the embodiment of FIG.

FIG. 52 is a circuit diagram of the twenty-fourth embodiment.

FIG. 53 is a characteristic diagram showing the relationship between the power supply voltage and the gate on time.

54 is an operation waveform diagram of FIG. 52.

FIG. 55 is a circuit diagram of the twenty-fifth embodiment.

FIG. 56 is a characteristic diagram of the variable inductor of the example.

57 is an operation waveform diagram of FIG. 55.

FIG. 58 is a circuit diagram of the twenty-sixth embodiment.

FIG. 59 is a characteristic diagram of the variable inductor used in the example.

FIG. 60 is an operation waveform diagram of FIG. 58.

FIG. 61 is a circuit diagram of a conventional discharge lamp lighting device.

FIG. 62 is a circuit diagram showing another conventional example.

FIG. 63 is a circuit diagram showing still another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC power supply 2 Switching part 3 Transformer 4 High voltage generating circuit 5 Discharge lamp 8 Control circuit 21,22 Switching element 23,24 Diode 25,26 Capacitor 27,28,29,30 Switch 91,92 Current regeneration block 311,312 Input winding 313 Output winding 911,921 Variable inductor 912,922 Switch 913,923 Saturable reactor

Claims (7)

[Claims] 1. A direct current power supply, a switching element, a transformer, a current regeneration block, a control circuit, and a discharge lamp, the transformer having two input windings. One end of each winding is connected to the positive output of the DC power supply so as to have different polarities, and the other end is connected to the negative output of the DC power supply via the switching element, and A high voltage and an AC output voltage are applied to the discharge lamp connected to the output winding by connecting the current regeneration block to at least one of the one end and the other end, and driving the switching element and the current regeneration block by the control circuit. A discharge lamp lighting device adapted to apply a voltage. 2. The discharge lamp lighting device according to claim 1, further comprising a switch for driving a high voltage output between a connection point between the input winding of the transformer and the current regeneration block and the negative output of the DC power supply. 3. The discharge lamp lighting device according to claim 1, wherein the transformer has a separate winding for driving the high voltage output on the primary side. 4. The discharge lamp lighting device according to claim 1, wherein the transformer has, on the secondary side, another winding for driving a high voltage output, which is connected via an insulating drive means or a diode. 5. The transformer has two cores facing each other in the same space.
The discharge lamp lighting device according to claim 1, claim 2, claim 3, or claim 4, which has voids having different lengths of points or more. 6. The control circuit according to claim 1, claim 2, claim 3, claim 4, or claim 5, wherein the control circuit controls the on-time of the switching element in response to a voltage change of the DC power supply when driving a high-voltage output. Discharge lamp lighting device. 7. The discharge according to claim 1, claim 2, claim 3, claim 4 or claim 5, wherein the current regeneration blocker is impedance controlled with respect to a voltage change of the DC power supply when driving a high voltage output. Electric lighting device.