JPH10326682A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device which can certainly keep the operating frequency of an inverter circuit to the phase delay region of the resonance frequency of a resonator circuit when a discharge lamp load having different starting voltage is to be started for lighting up using one unit of inverter circuit through resonator circuit. SOLUTION: A discharge lamp lighting device is equipped with a DC power supply 2 to make power conversion from AC main A into a DC voltage and an inverter circuit 1 to convert the output of the DC power supply 2 into a high frequency power. Through a resonator circuit, the output of the inverter circuit 1 is supplied to lamps La1 and La2 having different starting voltages and connected in parallel. The output voltage of the DC power supply 2 is set so that the operating frequency is kept to the phase delay region of the resonance frequency of resonator circuit when the operating frequency of the inverter circuit 1 is set so as to cause impression of that starting voltage of two lamps La1 and La2 which is the highest.

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 apparatus for lighting a plurality of lamps having different power consumptions at a high frequency.

[0002]

2. Description of the Related Art Conventionally, a discharge lamp lighting device of this type having a configuration shown in FIG. 22 is known. The illustrated discharge lamp lighting device converts the output of an inverter circuit 1 that converts a DC voltage into a high-frequency voltage into discharge lamp loads (hereinafter, referred to as lamps) La ₁ and La ₂ (for example, FC) with different power consumption.
L40W, FCL32W) to apply both lamps L
a ₁ and La ₂ are turned on at a high frequency.

[0003] DC voltage applied to the inverter circuit 1 as a power source, after full-wave rectified by the rectifier circuit composed of the AC power source AC from the diode bridge DB, are obtained by smoothing by the smoothing capacitor C _0. The inverter circuit 1 is of a half-bridge type and includes a series circuit of a pair of switching elements Q ₁ and Q ₂ composed of transistors. That is, the collector and the emitter of both switching elements Q ₁ and Q ₂ are connected in series, and this series circuit is connected between both ends of the smoothing capacitor C ₀ . Reflux diodes D ₁ and D ₂ are connected in anti-parallel to the respective switching elements Q ₁ and Q ₂ . In addition, each switching element Q _1, Q _2, the control signal generated by the control circuit CN ₁ driving circuit 3a
And the switching elements Q ₁ and Q ₂ are turned on and off alternately. That is, this inverter circuit 1
Is separately excited.

[0004] One switching element Q_TwoBetween both ends of
Is a DC cut capacitor C₁₁And inductor L_{twenty one}When
Capacitor C_{twenty one}And a series circuit is connected.
Flow cut capacitor C₁₂And inductor L_{twenty two}And conde
Sensor C_{twenty two}Are connected in series. Inductor L_{twenty one}When
Capacitor C_{twenty one}And inductor L_{twenty two}And capacitor C_{twenty two}
Each constitute a resonance circuit, and a capacitor C_{twenty one},
C_{twenty two}Each has a lamp La₁, La_TwoAre connected in parallel
You. More specifically, the lamp La₁, La_TwoAs the heat
Using a fluorescent lamp with a filament that is the cathode
Each lamp La ₁, La_TwoNon-power of each filament
Capacitor C across one side_{twenty one}, C_{twenty two}Connect each
is there.

If such a configuration is adopted, the consumption of the lamps La ₁ and La ₂ can be improved by appropriately setting the combination of the capacitors C ₁₁ and C ₁₂ and the inductor L ₂₁ and the combination of the capacitors C ₁₂ and C ₂₂ and the inductor L _22. It can be started and lit even if the power is different. Here, the capacitor C
_11, together with the C ₁₂ has a function as a capacitor for cutting direct current, also has a function of giving an electric charge charged in the ON period of the switching element Q ₁ to the lamp La _1, La ₂ during the on period of the switching element Q ₂ ing.

When the switching elements Q ₁ and Q ₂ are alternately turned on and off by the control signal from the control circuit CN ₁ to operate the inverter circuit 1, the on / off frequency of the switching elements Q ₁ and Q ₂ of the inverter circuit 1 (hereinafter, referred to as “the switching frequency”). Operating frequency) and the resonance frequencies of the resonance circuits RS ₁ , RS ₂ composed of the capacitors C ₂₁ , C ₂₂ and the inductors L ₂₁ , L ₂₂ connected to the lamps La ₁ , La ₂ , respectively. Different power can be supplied to the lamps La ₁ and La ₂ . That is, it is possible to light the lamp La _1, La ₂ by respectively applying the appropriate starting voltage to the lamp La _1, La ₂ having different power consumption. The lamp La _1, of La ₂ after lighting, by the control circuit CN ₁ to change the operating frequency of the switching elements Q _1, Q ₂ to maintain the lighting of the lamp La _1, La _2.

[0007]

[SUMMARY OF THE INVENTION Incidentally, in the discharge lamp lighting device shown in FIG. 22, properly the voltage across the smoothing capacitor C ₀ if it is designed approximately 140 be substantially constant
It is kept at V. On the other hand, since the lamps La ₁ and La ₂ have different power consumptions, they have different starting voltages.
The starting voltage of CL40W is approximately 400V, and FCL32
The starting voltage of W is approximately 300V.

Therefore, the operating frequency of the inverter circuit 1 is
Frequency f in FIG._TwoIs set to 32W (FCL32
W) Lamp La_TwoTo provide sufficient starting voltage for
But 40W (FCL40W) lamp La₁
Is not enough to start. On the other hand, 40W lamp L
a₁The inverter circuit 1
Operating frequency of the above frequency f_TwoResonant circuit RS₁,
RS_Two(RS₁≒ RS _Two) Resonance frequency f₀Close to
Frequency f₁It is necessary to set to.

However, current stress of the resonance circuit RS _1, RS ₂ of the resonance frequency switching elements to Q ₁ f ₀ becomes close when the inverter circuit 1, Q ₂ switching elements Q ₁ and a large current flows in, Q ₂ is increased With
Switching loss at the time of switching on / off of the switching elements Q ₁ and Q ₂ increases. That is, the efficiency of the inverter circuit 1 decreases.

Further, the resonance circuit RS₁, RS_TwoMake up
Inductor L_{twenty one}, L_{twenty two}And capacitor C_{twenty one}, C_{twenty two}Rose
The resonance frequency f of the resonance circuit₀Varies,
In addition, the operation circuit of the inverter circuit 1 for applying the starting voltage
Since the wave number also varies,
The operating frequency of the inverter circuit 1 is set to the resonance circuit RS₁, RS
_TwoResonance frequency f₀If the frequency is set close to
Vibration circuit RS₁, RS_TwoResonance frequency f₀In the fast-advancing region of
The inverter circuit 1 may operate. like this
The operating frequency of the inverter circuit is the resonance circuit RS₁, RS
_TwoResonance frequency f ₀In the phase advance region of
Element Q₁, Q_TwoIs destroyed.

As described above, when one inverter circuit sharing lamps La ₁ and La ₂ having different power consumptions (mainly having different starting voltages) is to be started and lit, the switching elements Q ₁ and Q are turned on at the time of starting. _In some cases, excessive current may flow through the device and cause damage. In order to prevent such destruction, it is necessary to separately provide a protection circuit, which complicates the configuration of the discharge lamp lighting circuit, and causes a problem of an increase in cost due to an increase in the number of parts.

The present invention has been made in view of the above circumstances, and an object of the present invention is to start a plurality of discharge lamp loads having different power consumptions (starting voltages) by a single inverter circuit via a resonance circuit. In this case, it is an object of the present invention to provide a discharge lamp lighting device that reliably keeps the operating frequency of an inverter circuit in a region where the resonance frequency of the resonance circuit is late.

[0013]

According to the first aspect of the present invention, there is provided a DC power supply, an inverter circuit for converting an output of the DC power supply to high-frequency power, and power consumption connected in parallel to an output of the inverter circuit via a resonance circuit. A plurality of discharge lamp loads different from each other, and the output voltage of the DC power supply is set such that the operating frequency of the inverter circuit for starting the discharge lamp load is maintained in a phase lag region of the resonance frequency of the resonance circuit. . According to this configuration, the operating frequency of the inverter circuit is set in the delay region of the resonance frequency of the resonance circuit by appropriately setting the voltage of the DC power supply which is the input to the inverter circuit in order to obtain the starting voltage of the discharge lamp load. Therefore, the inverter circuit can be prevented from being broken with a simple configuration without requiring a special protection circuit for preventing the breakdown due to the operation in the phase advance region. In particular, when starting and lighting a plurality of loads having different power consumptions with one inverter circuit, it is difficult to design the resonance circuit and set the operating frequency of the inverter circuit. Since the setting is made by setting the voltage on the side, the design becomes easy.

According to a second aspect of the present invention, in the first aspect of the present invention, the DC power supply is a step-up chopper circuit. In this configuration, it is easy to control the output voltage of the DC power supply, and since it is a step-up chopper circuit, the voltage of the DC power supply, which is the input to the inverter circuit, increases, and the starting voltage can be easily obtained. According to a third aspect of the present invention, in the second aspect of the present invention, the inverter circuit and the chopper circuit both include a switching element that switches at a high frequency, and the switching elements of the inverter circuit and the DC power supply are switched at the same frequency. It is provided with a control circuit that performs According to this configuration, since the operations of the inverter circuit and the chopper circuit are linked, a part of the circuits can be commonly used for the control of the inverter circuit and the control of the chopper circuit, and the circuit configuration is simplified.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the DC power supply includes a first rectifier circuit for performing full-wave rectification on the AC power supply, a second rectifier circuit for performing voltage double rectification on the AC power supply, Switching means for selecting one of the outputs of the first rectifier circuit and the second rectifier circuit is provided. According to this configuration, the input voltage to the inverter circuit is switched between at the time of starting and at the time of steady lighting, so that the voltage stress of the inverter circuit is small.

According to a fifth aspect of the present invention, in the first aspect, the inverter circuit includes an output transformer between the discharge lamp load and the DC power supply includes a feedback winding provided in the output transformer, an input power supply, and an inductor. In addition to providing a series circuit with a capacitor, a voltage across the smoothing capacitor connected to the series circuit of the feedback winding and the capacitor via a rectifying element is used as an output voltage. According to this configuration, a part of the output energy is fed back to the input side via the transformer, and the voltage between both ends of the smoothing capacitor can be boosted from the voltage of the input power supply by the action of the feedback winding, the inductor, and the capacitor. Therefore, it is easy to obtain a voltage necessary for starting lighting as in the case of using the boost type chopper circuit. In addition, since the voltage across the smoothing capacitor can be boosted without using a switching element, the circuit configuration is simpler than when a chopper circuit is used.

According to a sixth aspect of the present invention, in the first aspect of the invention, the inverter circuit includes a switching element that switches at a high frequency, the DC power supply includes a smoothing capacitor whose both-ends voltage is used as a power supply of the inverter circuit, and the switching element. And a series-connected inductor, and a backflow prevention element inserted in a path for discharging energy stored in the inductor when the switching element is turned on to the smoothing capacitor when the switching element is turned off. In this configuration, since at least a part of the switching elements of the inverter circuit also functions as the switching elements of the chopper circuit, the number of switching elements can be reduced as compared with the case where the chopper circuit is provided.

According to a seventh aspect of the present invention, in the first aspect, a resonance circuit is provided between each discharge lamp load and the inverter circuit, and the resonance frequencies of the resonance circuits are set to be substantially equal. is there. According to this configuration, while setting the characteristics of the resonance circuit according to each discharge lamp load,
Since the resonance frequencies of the resonance circuits are substantially equal, setting of the operation frequency of the inverter circuit becomes easy.

According to an eighth aspect of the present invention, in the first aspect of the invention, the output voltage of the DC power supply is kept substantially constant regardless of the operation of the inverter circuit. With this configuration, the output voltage of the DC power supply is kept constant even if the operation of the inverter circuit changes, so that an excessive voltage is applied to the inverter circuit or an excessive current flows through the inverter circuit. Can be prevented.

According to a ninth aspect of the present invention, in the first aspect of the present invention, the output voltage of the DC power supply is a period during which the inverter circuit is stopped, a period during which the discharge lamp load is preheated, a period during which the discharge lamp load is started, and a period during which the discharge lamp load is turned on. Are set higher in this order.
According to this configuration, by setting the output voltage of the DC power supply according to each operation state of the inverter circuit, it is possible to prevent an excessive voltage from being applied to the inverter circuit and an excessive current from flowing through the inverter circuit. can do.

According to a tenth aspect of the present invention, in the third aspect, the control circuit activates the chopper circuit after the operation of the inverter circuit when the power is turned on, and stops the inverter circuit after the chopper circuit is stopped when the power is turned off. is there. According to this configuration, it is possible to prevent the output voltage of the chopper circuit from abnormally increasing due to the light load of the chopper circuit.

According to an eleventh aspect of the present invention, in the third aspect, the control circuit activates the inverter circuit after the operation of the chopper circuit when the power is turned on, and stops the chopper circuit after the inverter circuit is stopped when the power is turned off. is there. With this configuration, unstable operation of the inverter circuit due to shortage of the input voltage can be prevented. Claim 12
According to a third aspect of the present invention, in the third aspect, the control circuit changes the on-duty of the switching element of the inverter circuit according to a change in the state of the discharge lamp load, and keeps the on-duty of the switching element of the chopper circuit constant. is there. According to this configuration, it is possible to prevent the output voltage of the chopper circuit from being substantially constant and applying an excessive voltage to the inverter circuit, or to prevent an excessive current from flowing through the inverter circuit. By changing the on-duty of the switching element, power supply suitable for preheating and dimming of the discharge lamp load can be performed.

According to a thirteenth aspect of the present invention, in the third aspect of the invention, the control circuit changes the on-duty of the switching element of the chopper circuit in accordance with a change in the state of the discharge lamp load, and the on-duty of the switching element of the inverter circuit is changed. Is kept constant. According to this configuration, an abnormal increase in the output voltage of the chopper circuit can be prevented by adjusting the on-duty of the switching element of the chopper circuit during a light load or the like.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION

(Basic Configuration) In each of the embodiments described below, as shown in FIG. 1, a plurality of lamps La ₁ and La ₂ having different power consumptions are started and lit by the output of an inverter circuit 1, which is a conventional example. The common configuration is to control the output voltage of the DC power supply 2 that applies the input voltage to the inverter circuit 1 so that the problem described above does not occur. As the DC power supply 2, a power supply such as a commercial power supply that converts an AC power supply AC into a DC power supply is used. The inverter circuit 1 turns on the lamps La ₁ and La ₂ at a high frequency of several tens of kHz.

(Embodiment 1) The one shown in FIG.
The source 2 uses a step-up chopper circuit.
The control of the DC power supply 2 is performed by the control circuit C of the inverter circuit 1.
N₁Control circuit CN independent of₀Is used. Other structures
The configuration is the same as the conventional configuration shown in FIG. DC power supply 2
Is a diode bridge for full-wave rectification of AC power
The inductor L is connected between the DC output terminals of the rectifier circuit DB.₀When
Switching element Q composed of MOSFET₀Series times with
Circuit and the switching element Q₀Between both ends
Do D ₀And smoothing capacitor C₀Connected with a series circuit with
Have In this circuit, the control circuit CN₀Is a switch
Element Q₀Control signal to turn on and off the
Signal, the smoothing capacitor C₀DC voltage across
Is obtained.

The operation of this type of DC power supply 2 is well known.
There is a brief explanation. This DC power supply 2 is switched
Element Q₀During the ON period of the
And inductor L₀Accumulates energy in the switching element
Child Q₀In the off period of the inductor L₀Energy stored in
Iod D₀Through the smoothing capacitor C₀I will release it to
It works as follows. Inductor L₀Energy storage
When releasing energy, the output voltage of the rectifier circuit DB is
Kuta L₀The voltage across the
C₀Is higher than the output voltage of the rectifier circuit DB.
You. That is, the DC power supply 2 is input to the rectifier circuit DB.
Boosts the voltage of AC power supply AC, converts it to DC power and outputs
Will do. As is clear from this operation,
The switching element Q₀On-off dew
By changing the inductor ratio, the inductor L₀Energy storage
Because the gear changes, the control circuit CN₀Switch on
Element Q₀By controlling the duty ratio of
Sa C₀Can be adjusted. There
And the lamp La₁, La_TwoOf DC power supply 2 when starting
Control circuit CN so that is set relatively high.₀Works
Let the lamp La₁, La _TwoSecure the starting voltage of

The resonance frequencies of the resonance circuits provided for each of the lamps La ₁ and La ₂ are desirably set to be substantially equal, and the inductors L ₂₁ and L ₂₂ are determined by the rated currents of the lamps La ₁ and La ₂ . Further, the output voltage of the DC power supply 2 is set such that the operating frequency of the inverter circuit 1 is maintained in the late phase region when the highest starting voltage of the lamps La ₁ and La ₂ is generated.

Specifically, fluorescent lamps of FCL40W and FCL32W are used as the lamps La ₁ and La ₂ . As described as a conventional example, FCL40W, FC
The starting voltage of L32W is approximately 400V and approximately 300V, respectively.
A V, the starting of approximately 400V in a ramp La ₁ while operating the inverter circuit 1 at a sufficiently high operating frequency than the resonant frequency of the resonant circuit composed of the inductor L ₂₁ and capacitor C ₂₁ Metropolitan in the circuit arrangement of FIG. 2 To apply a voltage, the DC power supply 2 needs an output voltage of about 250V. In the present embodiment, since the step-up chopper circuit is used as the DC power supply 2 as described above, the control circuit CN ₀
By appropriately controlling the switching element Q ₀ , the DC power supply 2 can boost the voltage to about 250 V even if the voltage of the AC power supply AC (50 Hz or 60 Hz) is 100 V.

As described above, when the lamps La ₁ and La ₂ are started, the output voltage of the DC power supply 2 is boosted to approximately 250 V. Therefore, the inductor L ₂₁ ,
L ₂₂ and capacitor C _21, C ₂₂ Metropolitan flowing oscillating current in the resonant circuit composed of a capacitor C _21, each respective lamp voltage across the C ₂₂ La ₁ caused by the vibration current, La
_By applying the voltage to ₂ , a starting voltage of approximately 400 V and approximately 300 V can be obtained. Also, the lamp La
_Since the operating frequency of the inverter circuit 1 can be set sufficiently higher than the resonance frequency of the resonance circuit at the time of starting the _first and La ₂ , the operation near the resonance frequency of the resonance circuit or in the fast phase region can be avoided. As a result, destruction of the switching elements Q ₁ and Q ₂ can be prevented. In addition,
In this embodiment, the switching elements Q ₁ and Q ₂ are MOSF
Since ET is used, the parasitic diode of the MOSFET functions as a freewheeling diode. Therefore, there is no need to separately provide a reflux diode.

(Embodiment 2) In Embodiment 1, the DC power supply 2
And the control circuit CN ₁ of the inverter circuit ₁
However, in the present embodiment, as shown in FIG. 3, a chopper control signal for controlling the chopper circuit 2 in response to an inverter control signal for controlling the inverter circuit 1 is generated. Control circuit CN configured in
Is used. The control circuit CN includes switching elements Q ₁ , Q
Oscillation circuit 11 for outputting a reference signal for determining a _second switching frequency (operation frequency of the inverter circuit 1)
And an inverter control circuit 12 receiving the output of the oscillation circuit 11 and outputting a rectangular wave inverter control signal having the same frequency as the reference signal and determining the ON periods of the switching elements Q ₁ and Q _2. in synchronization with the falling edge of the inverter control signal outputted consisting chopper control circuit 13 for generating a chopper control signal to turn on the switching element Q _0. Therefore, switching elements Q ₀ -Q between inverter circuit 1 and chopper circuit 2
₂ are controlled at the same frequency in conjunction with each other. The reference signal output from the oscillation circuit 11 is set to several tens of kHz.
Drive circuit 3a of the switching element Q ₀ to Q ₂ in FIG. 3,
3b and a driving circuit power supply 4 for supplying power to the driving circuits 3a and 3b.
Is also shown as a specific circuit.

The driving circuit 3a includes a transistor Q₁₁,
Q₁₂, Q_{twenty one}, Q_{twenty two}Complementary pair consisting of
Of each pair that constitute a complementary pair.
Jista Q ₁₁, Q₁₂And Q_{twenty one}, Q_{twenty two}Connection between emitters
The point is each switching element Q₁, Q _TwoConnected to the gate of
You. Also, the switching element Q_TwoCompliment to drive
Repair (transistor Q_{twenty one}, Q_{twenty two}) Inverter
The inverter control signal from the control circuit 12 is directly given.
Switching element Q₁Complementary driving
Pair (transistor Q₁₁, Q₁₂) Is the inverter control time
If the inverter control signal from the path 12 is
Inverting element Q_FourGiven by inverting the logic level through
It is. With this configuration, the inverter control signal is at H level
During the switching element Q₁Is switched off
Element Q_TwoTurns on and the inverter control signal goes low.
During the switching element Q₁Is switched on
Element Q_TwoTurns off. In other words, one inverter control
Both signals are switched by passing the signal through the drive circuit 3a.
Element Q₁, Q_TwoCan be turned on and off alternately.

The power supply 4 for the drive circuit is a smoothing capacitor C₀of
Resistance R connected between both ends_FourAnd Zener diode
For example, 12V) ZD_FourSeries circuit and Zenerda
Iod ZD_FourCapacitor C connected in parallel to_FourAnd from
Become. Transistor Q_{twenty one}, Q _{twenty two}Complementary repair
Has a capacitor C_FourIs applied as power supply
You. The capacitor C_FourDiode D_Four
And capacitor C_FiveAnd switching element Q_TwoSeries circuit with
Are connected, and the switching element Q_TwoDuring the on period of
Sensor C_FiveIs charged. Therefore, the capacitor C_Fiveof
The voltage between both ends is capacitor C_FourRises to about the voltage across
I do. Capacitor C_FiveVoltage across the transistor Q₁₁,
Q₁₂As a power source.
With this configuration, the base of each complementary repair
The reference potential is applied to each switching element Q₁, Q_TwoMatch the reference potential of
It is also shifting.

The drive circuit 3b for driving the switching element Q ₀ of the DC power source 2, the transistor Q _01, made of complementary pairs Q _02, gates of the transistors Q _01, a connection point between the emitters of Q ₀₂ is the transistor Q ₀ Connected to. Also, a chopper control signal output from the chopper control circuit 13 is given to this complementary pair. Therefore, the switching element Q ₀ is turned on while the chopper control signal is at the H level. As described above, since the chopper control signal is synchronized with the inverter control signal, it has a high frequency of several tens of kHz similarly to the inverter control signal, and turns on and off the switching element Q ₀ in synchronization with the switching elements Q ₁ and Q _2. Will be.

In this configuration, when the frequency of the reference signal output from the oscillation circuit 11 is changed in order to change the operating frequency of the inverter circuit 1, the frequency of the chopper control signal also changes. In addition, 10
The 0 V AC power supply AC can be boosted to a DC voltage of approximately 250 V, and the lamps La ₁ and La ₂ can be operated while the operating frequency of the inverter circuit 1 does not reach the fast phase region of the resonance frequency of the resonance circuit at the time of starting. Can be applied with a required starting voltage. As a result, the destruction of the switching elements Q ₁ and Q ₂ can be prevented.

FIG. 4 shows the operation waveforms of the above-described components. FIG. 4A shows a reference signal output from the oscillation circuit 11, and FIG.
4B illustrates an inverter control signal output from the inverter control circuit 12, and FIG. 4C illustrates a chopper control signal output from the chopper control circuit 13. FIGS.
(F) shows a current flowing through each switching element Q ₀ to Q _2, respectively.

By the way, the circuit configuration shown in FIG. 3 can be simplified as shown in FIG. 5 by omitting the drive circuit and the like. In the circuit configuration shown in FIG. 5, a step-up chopper circuit is used as the DC power supply 2 serving as the input power supply of the inverter circuit 1, and the operation of the inverter circuit 1 and the DC power supply 2 starts or operates according to the usage mode and purpose. Control the order of shutdown. That is, when the power is turned on and when the power is turned off, each of the inverter circuit 1 and the DC power supply 2 is operated or stopped first. Therefore, there are a total of four combinations.

First, when the power is turned on, it may be desirable to start the operation of the switching elements Q ₁ and Q ₂ of the inverter circuit 1 before the switching element Q ₀ of the DC power supply 2. This control is performed, for example, on the lamps La ₁ and La ₂
This is effective when sufficient preheating of the lamp is desired (the lamp life can be maintained long if sufficient preheating is performed). Although the time of preheating which may voltage across the smoothing capacitor C ₀ which is provided to the DC power supply 2 from the load of the inverter circuit 1 is a light load is increased abnormally, be operated inverter circuit 1 before the DC power supply 2 , it is possible to avoid an abnormal rise in the voltage across the smoothing capacitor C _0. Moreover, operating the DC power supply 2 from the previous operation of the inverter circuit 1 is not limited to the case of the preheating, since the voltage across the smoothing capacitor C ₀ is likely to abnormally increase, the order is selected in the normal use mode Is done.

On the other hand, the DC power supply 2 may be operated before the operation of the inverter circuit 1 even when the power is turned on. For example, when instantaneous starting is required, a sufficiently high starting voltage is applied to the lamps La ₁ and La ₂ for such a purpose of use.
Must be applied to Therefore, it is to operate the inverter circuit 1 after the direct current power source 2 is operated to previously increase the voltage across the smoothing capacitor C ₀ than the inverter circuit 1. As a result, a stable high DC voltage is applied to the inverter circuit 1, and when the inverter circuit 1 is started, the lamps La ₁ and La ₂ can be started immediately.

When the power is cut off, generally, after the operation of the switching element Q ₀ of the DC power supply 2 is stopped (or simultaneously), the switching elements Q ₁ and Q _{2 of the} inverter circuit 1 are turned off.
Is desirably stopped. This is because if the operation of the inverter circuit 1 is stopped _first , the lamps La ₁ , La ₂
There will be a DC power source 2 is a light load off immediately, as a result, there because the voltage across the smoothing capacitor C ₀ rises abnormally, to prevent abnormal rise of the voltage across the smoothing capacitor C _0, the DC It is desirable that the operation of the power supply 2 be stopped before the operation of the inverter circuit 1.

On the other hand, in some cases, it is desirable to stop the operation of switching element Q ₀ of DC power supply 2 after the operation of switching elements Q ₁ and Q ₂ of inverter circuit 1 is stopped when the power is cut off. For example, if the power consumption of the lamps La ₁ and La ₂ is different and the starting voltage is high, the operating frequency of the inverter circuit 1 must be set in a region close to the resonance frequency of the resonance circuit. If the operation of the DC power supply 2 is stopped first, the input voltage of the inverter circuit 1 decreases, the operation of the inverter circuit 1 becomes unstable, and the operating frequency of the inverter circuit 1 may enter the phase advance region. In order to avoid such a situation, it is desirable to stop the inverter circuit 1 before the DC power supply 2.

As described above, the operation timings of the inverter circuit 1 and the DC power supply 2 are appropriately set according to the use form and the purpose of use. Other configurations and operations are the same as those of the first embodiment. Embodiment 3 In this embodiment, as shown in FIG. 6, a rectifier circuit capable of switching between a function as a normal full-wave rectifier circuit and a function as a voltage doubler rectifier circuit is used as the DC power supply 2. That is, a series circuit of a pair of smoothing capacitors C ₀₁ and C ₀₂ is connected between the DC output terminals of the rectifier circuit DB, one end of the AC power supply AC is connected to one AC input terminal of the rectifier circuit DB, and the AC power supply AC Is connected to the other AC input terminal of the diode bridge DB and the capacitor C ₀₁ ,
It is provided change-over switch SW ₀ of the switching means for selectively connecting the connection point of the C _02.

When the AC input terminal of the rectifier circuit DB is selected by the changeover switch SW ₀ , the DC output voltage of the rectifier circuit DB is applied to both ends of the series circuit of the smoothing capacitors C ₀₁ and C ₀₂ . Functions as a full-wave rectifier circuit. When the connection point between the smoothing capacitors C ₀₁ and C ₀₂ is selected by the changeover switch SW _{0, a} bridge circuit is formed by one arm of the rectifier circuit DB and the capacitors C ₀₁ and C _02, and the AC power supply AC Since each of the capacitors C ₀₁ and C ₀₂ is charged in each half cycle of the voltage waveform, the voltage between both ends of the series circuit of the capacitors C ₀₁ and C ₀₂ is approximately twice the peak voltage of the AC power supply AC.

Thus, the output voltage of the DC power supply 2 is given to the inverter circuit 1 and the lamps La ₁ , La ₂
During the steady lighting is functioning DC power supply 2 as the full-wave rectifier circuit, by selecting the changeover switch SW ₀ so as to function as a voltage doubler rectifier circuit during start, than rated operation input voltage of the inverter circuit 1 during start-up The voltage required for starting the lamps La ₁ and La ₂ can be obtained while the inverter circuit 1 is not operated in the early phase region. After the lamps La ₁ and La ₂ are turned on, the switches are switched by the changeover switch SW ₀ so as to function as a full-wave rectifier circuit. Other configurations and operations are the same as those of the first embodiment.

[0044] In Embodiment 4 This embodiment, as shown in FIG. 7, the DC power source 2, an AC power source AC is full-wave rectified by the rectifier circuit DB, the output voltage of the rectifier circuit DB by the smoothing capacitor C ₀ Is used.
The inverter circuit 1 is used as a half bridge type including the output transformer T _1. Further, the switching elements Q ₁ and Q ₂ constituting the inverter circuit 1 are self-excited.

[0045] The output voltage of the DC power source 2 in this embodiment in order to vary, the feedback winding n ₃ provided on the output transformer T _1, the inductor L between the AC power supply AC and the rectifying circuit DB
₃ , and a configuration in which a series circuit of the feedback winding n ₃ and the feedback capacitor C ₃ is connected between the AC input terminals of the rectifier circuit DB. Since part of the output of the inverter circuit 1 is fed back to the input side of the rectifier circuit DB This configuration voltage across the smoothing capacitor C ₀ is changed in accordance with the feedback amount.

This will be described more specifically. Inverter circuit
1 is a smoothing capacitor C as in the first embodiment.₀Between both ends of
Switching element Q connected to₁, Q_TwoSeries circuit
Prepare. Each switching element Q₁, Q_TwoIs a transistor
And each switching element Q₁, Q_TwoCollector
A diode D for reflux is provided between the emitters.₁, D _Two
Are connected in antiparallel. One switching element Q₁of
Capacitor C for DC cut between both ends₁And output transformer
S₁Primary winding n₁And the primary winding of the current transformer CT
Are connected in series. The current transformer CT is 2
Secondary windings, each secondary winding being
Element Q₁, Q_TwoConnected to bias the
You. Here, the output transformer T₁To current transformer CT
When current flows toward the switching element Q_TwoBut
From the current transformer CT to the output transformer T₁To
When the current flows, the switching element Q₁Is on
The secondary winding of the current transformer CT switches
Element Q₁, Q_TwoConnected to. Smoothing capacitor C₀of
Resistance R between both ends₆And capacitor C₆Series circuit with
The resistance R₆And capacitor C₆Connection point and switch
Ching element Q_TwoLike a diac between the base
Trigger element Q₆Is connected. Resistance R₆, Conden
Sa C₆, Trigger element Q₆Constitutes a start-up circuit,
Densa C₀Rises across the resistor R₆Through the con
Densa C₆Is charged and the capacitor C₆Voltage across
Riga element Q₆Switch when the breakover voltage is reached
Element Q _TwoIs turned on.

Switching element Q_TwoIs turned on,
Smoothing capacitor C₀From capacitor C ₁And output transformer T
₁And current transformer CT and switching element Q_TwoThrough
Current flows, and then the capacitor C₁As the charging progresses
Switching element Q_TwoTurns off, and the current
Is detected by the current transformer CT and the switching element Q
₁Turns on. After that, repeat the same operation to switch.
Ching element Q₁, Q_TwoAre turned on and off alternately. Resistance R
₆And capacitor C₆Connection point and switching element
Q₁, Q_TwoDiode D connected between the connection point₆
Means that the capacitor C₆Is discharged.

As described above, since the inverter circuit 1 operates in a self-excited manner, the operating frequency changes according to the magnitude of the load. However, the operating frequency in a state where the lamps La ₁ and La ₂ are connected is set so as to be in a delay region of the resonance frequency of the resonance circuit including the inductors L ₂₁ and L ₂₂ and the capacitors C ₂₁ and C _22. You. By the way, as described above, the inductor L ₃ and the capacitor C ₃
And the feedback winding n ₃ , a resonance current flows through a resonance circuit formed by the inductor L ₃ and the capacitor C _3. Therefore, the resonance voltage generated by the resonance current is added to the voltage of the AC power supply AC. in is applied to the rectifier circuit DB, inductor L _3, a capacitor C _3, the voltage across the smoothing capacitor C ₀ than when not a feedback winding n ₃ provided is to be boosted. That is, the inductor L ₃ is boosted by performing the release and accumulation of inductors and similar energy use in the chopper circuit of the step-up. The filter circuit F the radio frequency of about the operating frequency of the inverter circuit 1 is made of a low-pass filter in order to prevent infiltration of the AC power source AC is between the AC power source AC and the inductor L ₃
Is inserted.

[0049] Also the configuration of the present embodiment, it is possible to obtain a DC voltage of approximately 250V from the AC power supply AC of 100V to the power supply of the inverter circuit 1, the inductor L _21, L
₂₂ and while setting the operating frequency of the inverter circuit 1 at a sufficiently high frequency than the resonance frequency of the resonance circuit consisting of capacitor C _21, C _22, it is possible to obtain a starting voltage of the lamp La _1, La ₂ (e.g., FCL40W A starting voltage of about 400 V required for starting lighting of the battery can be obtained.) In other words, since the inverter circuit 1 does not operate in the fast phase region of the resonance circuit when starting the lamps La ₁ and La ₂ , it is possible to prevent the switching elements Q ₁ and Q ₂ from being destroyed.

When the lamps La ₁ and La ₂ are turned on, the output of the inverter circuit 1 mainly outputs the lamps La ₁ and La 2.
Since it supplied to _2, rectifier circuit D through the feedback winding n ₃
The amount of power fed back to the input side is reduced in B, the voltage across the smoothing capacitor C ₀ is lower than at startup. In the above configuration, it is possible to set the input voltage of the inverter circuit 1 appropriately by changing the number of turns of the feedback winding n ₃ of the output transformer T _1. Other configurations and operations are described in the first embodiment.
Is the same as

(Embodiment 5) This embodiment is shown in FIG.
Thus, in the conventional configuration shown in FIG.
Sa C₀Is omitted, and the direct current of the rectifier circuit DB is used instead.
Capacitor C between output terminals₇And discharge diode D₇When
Capacitor C₉Connected in series with the capacitor C₉
Diode D₉And a capacitor C₇And die
Aether D₇And the switching element Q₁, Q_Twoof
Inductor L between the connection point₇And charging diode D
₈And a capacitor C₇And da
Iod D₇In the series circuit with₇More than
A sufficiently small capacitor C ₈Are connected in parallel.
Has adopted. Capacitor C₇Has a switching element Q
₁Inductor L during the ON period of₇The charging current flows through
Switching element Q_TwoDuring the ON period of the capacitor C
₇Discharges. Therefore, the switching element Q₁And Lee
Nacta L₇And diode D₇, D₈And capacitor C₇
Is the same as the step-down chopper circuit.
Works in the same way.

With the configuration described above, the inverter circuit
Capacitor C for providing input voltage to path 1₇Voltage across
The voltage is lowered from the output voltage of the current circuit DB. Capacitor C
₇Is supplied to the inverter circuit 1 from the rectifier circuit D
Output voltage of B is capacitor C ₇Period lower than the voltage across
And the pulsating voltage waveform output from the rectifier circuit DB
In the valley of the capacitor C₇From inverter circuit 1
Will be supplied with power. Also, the operation of the inverter circuit 1
If the operation frequency changes, the capacitor C₇The voltage between both ends changes
Therefore, even in this configuration, the input voltage of the inverter circuit 1 is
Be adjustable. And the capacitor C₉And Daio
Code D₉Is provided, the inverter circuit 1
Part of the output is fed back to the input side, and the lamp La₁, La_Two
Light load during preheating before starting
Sa C₇Of the lamp La rises.₁, La
_TwoIt is possible to apply a starting voltage at the time of starting. other
The configuration and operation are the same as in the first embodiment.

Embodiment 6 In this embodiment, as shown in FIG. 9, an inverter circuit 1 having the same configuration as that of the embodiment 1 shown in FIG. 2 is used. DC power supply 2, inserts the series circuit of the inductor L ₀ and the diode D ₀ between the positive electrode and the connection point of the switching elements Q _1, Q ₂ of the DC output ends of the rectifier circuit DB, and the switching elements Q _1, the smoothing capacitor C ₀ to the series circuit Q ₂ 'are used as connected in parallel. In other words, the present embodiment also uses a step-up chopper circuit as the DC power supply 2 as in the first embodiment, but the switching element constituting the step-up chopper circuit is also used as one switching element Q ₂ of the inverter circuit 1. Is different.

[0054] Thus, the charging from the rectifier circuit DB to the on period of the switching element Q ₂ current flows through the inductor L ₀ and the diode D _0, the capacitor C ₀ through the parasitic diode of the switching element Q ₁ when the switching element Q ₂ is turned off Electric current flows. Here, since the both ends of the capacitor C ₀ sum voltage between the output voltage and the voltage across the inductor L ₀ of the rectifier circuit DB is applied, the voltage across the capacitor C ₀ than the output voltage of the rectifier circuit DB is boosted Will be. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 7) In this embodiment, as shown in FIG. 10, a pair of diodes constituting one arm of a rectifier circuit DB are shared by the parasitic diodes of the switching elements Q ₁ and Q ₂ composed of MOSFETs. Things. That is, the configuration of the inverter circuit 1 is the same as that of the first embodiment shown in FIG.
B, a pair of diodes D _b1 and D
The inductor L ₀ between the connection point of _b2, then connecting the connection point of the switching elements Q _1, Q ₂ constituting the inverter circuit 1 and the AC power source AC and the other end, the diode D
_b1, which are connected to the smoothing capacitor C ₀ across the D _b2. A series circuit of switching elements Q ₁ and Q ₂ is connected in parallel to the smoothing capacitor C ₀ .

[0056] The ON period of the switching element Q ₁ accumulated energy in the inductor L ₀ in a path passing through the inductor L ₀ and the diode D _b1 from the AC power source AC and the switching element Q _1, the switching element from the smoothing capacitor C ₀ at the same time feeding through Q ₁ to the lamp La _1, La _2.
The switching element Q ₁ is if off, being released in a path passing through the energy stored in the inductor L ₀ is the diode D _b1 and the smoothing capacitor C ₀ and the parasitic diode of the switching element Q ₂ and the AC power source AC, a smoothing capacitor C ₀
Is charged.

[0057] Similarly, inductor L ₀ in route to the on period of the switching element Q ₂ to which passing through the switching element Q ₂ and the diode D _b2 and the inductor L ₀ from the AC power source AC
At the same time, power is supplied from the capacitors C ₂₁ and C ₂₂ to the lamps La ₁ and La ₂ through the switching element Q ₂ . The switching element Q ₂ is if off, being released in a path that stored energy in the inductor L ₀ passes through the parasitic diode and a smoothing capacitor C ₀ and the diode D _b2 of the alternating current power supply AC and the switching element Q _1, a smoothing capacitor C Charge ₀ .

As is apparent from the above-described operation, energy is stored in the inductor L ₀ during the on-periods of both the switching elements Q ₁ and Q ₂ , and the switching elements Q ₁ and Q ₂
, The smoothing capacitor C ₀ is charged after turning off the current, so that a current can be almost uniformly supplied to both switching elements Q ₁ and Q ₂ , and stress is prevented from being applied to only one of the switching elements Q ₁ and Q _2. be able to.

[0059] Moreover, since functions similarly to the chopper circuit Boost As apparent from the above operation, there is can be boosted than the voltage across the voltage of the AC power supply AC to the smoothing capacitor C _0, smooth The starting voltage can be applied to each of the lamps La ₁ and La ₂ by raising the voltage across the capacitor C ₀ at the time of starting. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 8) In this embodiment, as shown in FIG. 11, the output voltage of the DC power supply 2 is monitored by the control circuit CN ₀ in the configuration of the embodiment 1 shown in FIG. The output voltage is kept almost constant. To keep the output voltage of DC power supply 2 constant, PWM
Adopting a general configuration of a control, it may be controlled on-duty of the switching element Q ₀ in accordance with the error between the output voltage and the reference voltage of the DC power supply 2.

The output voltage of the DC power supply 2 is fixed so as not to be affected by the voltage fluctuation of the AC power supply AC. At the time of starting, one of the lamps La ₁ and La ₂ is disconnected, The output voltage of the DC power supply 2 is kept substantially constant in a state where the light output of the lamps La ₁ and La ₂ is dimmed by changing the operating frequency of the circuit 1 and in a no-load state. This configuration, an overvoltage can be prevented to or overcurrent flows or is applied to the inverter circuit 1, with each other to eliminate the need for complicated structure as the control circuit CN _1.

The output voltage of the DC power supply 2 is an example.
12 may be controlled as shown in FIG. In the example shown
Non-operating period P of barter circuit 1₁, Lamp La₁, La_Two
Preheating period P of filament_Two, Lamp La₁, La_Two
Starting period P for starting_Three, Lamp La₁, La_TwoPoint of
Light period P_FourThe output voltage of the DC power supply 2 according to
I have. The lighting period P_FourAt all lighting (rated point
Lamp) and dimming lighting to change the output voltage of the DC power supply 2
Yes (V when all lights are on)_FourWhen dimming is on, V_Four’
There). Now, each period P₁~ P_FourOf DC power supply 2 at
Output voltage is V₁~ V_FourThen V₁<V_Two<
V_Three(<V_Four’) <V_FourSet to the relationship. This
If not, the non-operation period P₁Unnecessary power consumption
Pre-heating period P_TwoWithout starting the filament
Pre-heating is sufficient, and the starting period P _ThreeHas a DC power supply 2
The starting voltage can be obtained by increasing the output voltage. La
Pump La₁, La_TwoThe output voltage of DC power supply 2 after lighting
Is lowered from the start to stabilize the lighting state. What
Note that the output voltage should be lower at dimming than at full lighting.
When switching from full lighting to dimming lighting
The change width of the operating frequency of the circuit 1 can be reduced.
You. The operating frequency of the inverter circuit 1 is the delay phase of the resonance circuit.
Range, so that when dimming,
Also increase the operating frequency.
If the change in operating frequency when switching to the light is small,
Suppress increase in noise level due to change in operation frequency
(Radiation noise increases as the operating frequency increases
).

As described above, since the output voltage of the DC power supply 2 is adjusted in accordance with the operation of the inverter circuit 1, it is possible to prevent an overvoltage from being applied to the inverter circuit 1 or to prevent an overcurrent from flowing. The stress of each element constituting the circuit 1 can be reduced and the destruction of each element can be prevented. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 9) In this embodiment, as shown in FIG. 13, a load state detection circuit 5 for detecting the operation states of the lamps La ₁ , La ₂ ,... Is provided. The operating states of the lamps La ₁ , La ₂ ,...
Dimmed lighting, off-load, end of lamp life, etc. In particular, if no load is detected based on the output of the load state detection circuit 5 (the disconnection of the load is the same as the state where any of the lamps La ₁ , La ₂ ,. The output voltage of the DC power supply 2 which is the input power supply of the circuit 1 is reduced. In this way, it is possible to prevent an overvoltage from being applied to the inverter circuit 1 when there is no load, and to prevent destruction of elements.

(Embodiment 10) As shown in FIG. 14, this embodiment is different from the embodiment 2 shown in FIG.
Based on the outputs of the secondary windings provided on the inductors L ₂₁ and L ₂₂ constituting the resonance circuit, no load is applied and the lamps La ₁ and La
₂ is to detect the Emiless state at the end of life and to switch the outputs of the inverter control circuit 12 and the chopper control circuit 13 differently from the normal state for abnormalities such as no-load state and Emiless state. is there. Here, the Emiless state means a phenomenon in which the electron emission material (emitter) of the filament is consumed and electrons are less likely to be emitted from the filament, and as a result, only the half-wave of the AC power supply is turned on. If the electron emission material is exhausted and no longer emits light, it can be regarded as a no-load state.

The oscillation circuit 11 and the chopper control circuit 13 are the same as those in the second embodiment, but an Emiless / no-load detection circuit 14 for detecting an unloaded state or an Emiless state based on the secondary outputs of the inductors L ₂₁ and L _22. And a mode switching circuit 15 for changing the output of the oscillation circuit 11 and the chopper control circuit 13 based on the output of the Emiless / no-load detection circuit 14. The secondary windings of the inductors L ₂₁ and L ₂₂ are connected in series to capacitors C ₃₁ and C ₃₂ , respectively.
The series circuit of the next winding and the capacitors C ₃₁ and C ₃₂ is connected in parallel. The voltage between both ends of this parallel circuit is determined by the resistances R ₃₁ and R ₃₂
And is input to the Emiless / no-load detection circuit 14. While entering the no-load state and the Emiresu state Emiresu / no-load detecting circuit 14 is divided into two systems of voltage across the resistor R ₃₂ in the sense of being detected respectively in FIG,
The input to the Emiless / no-load detection circuit 14 may be performed by one system, and the processing may be internally divided into two systems. The voltage across the resistor R ₃₂ since no current flows through the primary winding of the inductor L _21, L ₂₂ is reduced in the no-load state, while the half-wave to the primary winding of the inductor L _21, L ₂₂ at Emiresu state in the voltage across the current limiting action is small resistor R ₃₂ because current flows is increased. In Emiresu / no-load detecting circuit 14 detects the no-load condition and Emiresu state based on such changes in the voltage across the resistor R _32.

When a no-load state or an emiless state is detected by the Emiless / no-load detecting circuit 14, the mode switching circuit 15 stops the operation of the oscillation circuit 11 and stops the operations of the DC power supply 2 and the inverter circuit 1. . Further, the output of the inverter control circuit 12 is set to L level. The oscillation circuit 11, the inverter control circuit 12, the chopper control circuit 13, the Emiless / no-load detection circuit 14, and the mode switching circuit 15 constitute a control circuit CN by one integrated circuit (bipolar integrated circuit), and the driving circuit 3a, 3b and the voltage across the capacitor C ₄ of the driver circuit power supply 4 to be used in common is supplied as a power supply. This integrated circuit is configured to start operating when the power supply 4 for the drive circuit rises to about 10 V (here, the breakover voltage of the Zener diode ZD ₄ is set to 12 V). During operation of the DC power supply 2 and the inverter circuit 1, the secondary winding output of the inductor L _21, L ₂₂ is smoothed by the capacitor C ₄ is rectified by the diode D _31, D _32. That is, power is supplied to the integrated circuit also from the secondary winding outputs of the inductors L ₂₁ and L ₂₂ . Where the resistance R
₄ is determined by the current capacity of the Zener diode ZD _4, to supply sufficient power alone for charging the capacitor C ₄ is the current through resistor R ₄ from the resistance value is relatively large with respect to the integrated circuit I ca n’t do it,
During operation of the inverter circuit 1 secondary winding output of the inductor L _21, L ₂₂ also be used in conjunction, with each other to be able to supply sufficient power.

Since the DC power supply 2 uses a step-up chopper circuit, and the power consumption in the inverter circuit 1 is reduced in a no-load state or an Emiless state, the smoothing capacitor provided at the output terminal of the DC power supply 2 is used. There is a possibility that the voltage across C ₀ rises abnormally, the voltage applied to the inverter circuit 1 becomes excessive, and the inverter circuit 1 is destroyed. Therefore, when the no-load condition and Emiresu condition is detected, to fix the output of the chopper control circuit 13 to the L level to turn off the switching element Q _0. If the switching element Q ₀ is on, but an excessive current to the switching element Q ₀ is inconvenient flows, the peak voltage across the ac power supply AC voltage of the capacitor C ₄ from turning off the switching element Q ₀ Value, and an abnormal rise can be prevented.

As described above, in the no-load state, the chopper control
The output of the control circuit 13 is set to L level, and the switching element Q
₀Is kept off, the inductor L_{twenty one}, L_{twenty two}Secondary winding
Capacitor C by output_FourCharging current to the
Densa C_FourMost of the charging current of R_FourTo the current passing through
Become. Therefore, sufficient power to drive the integrated circuit
Cannot be supplied, and the operation of the integrated circuit becomes
As a result, the operation of the inverter circuit 1 also stops. Up
When the operation of the integrated circuit stops, the capacitor C _FourBoth ends of
Since the voltage rises again, the integrated circuit resumes operation.
To operate the DC power supply 2 and the inverter circuit 1. Only
While starting operation, the capacitor C_FourVoltage across
And the integrated circuit stops operating again.
Repeat the work. That is, the DC power supply 2 and the inverter circuit 1
Means that the no-load condition disappears if the power is turned on.
Then, the stop and the operation are repeated. This state is shown in FIG.
It is shown in FIG. FIG. 15A shows a capacitor C_FourAnd resistance R_FourWhen
FIG. 15B shows the voltage applied to the series circuit of FIG.
Capacitor C_FourAnd the operation start voltage of the integrated circuit
FIG. 15C shows the operation of the integrated circuit.
5 shows an inverter control signal generated by the operation.

[0070] In the circuit shown in FIG. 14 are added to the power switch SW ₁ and the capacitor C ₁₀ for noise prevention. A resistor R ₄₁ , is connected between both ends of the smoothing capacitor C ₀ .
A series circuit of R ₄₂ are connected, pressurized by a resistor R _41, R ₄₂ min, the output voltage of the DC power supply 2 by the smoothed voltage is monitored by the capacitor C ₄₂ connected in parallel to the resistor R _42. The chopper control circuit 13 so as to keep the voltage constant, to control the switching element Q _0.

Now, in this circuit configuration, the oscillation circuit 11
It is assumed that the lamps La ₁ and La ₂ can be turned on at the rated operation when the frequency of the reference signal output from is set to about 50 kHz. The inverter control signal and the chopper control signal at the time of rated lighting are as shown in FIGS. Here, the inverter control signal is configured to the on-duty of about 50%, the chopper control signal to the timing of turn on of the switching element Q ₀ to maintain constant the voltage across the smoothing capacitor C ₀ is adjusted Adjusts the on-duty. That is, if the voltage across the resistor R _41, R ₄₂ and a smoothing capacitor C ₀ that is detected by the capacitor C ₄₂ is increased on-duty is reduced, the on-duty is increased if drop voltage across the smoothing capacitor C ₀ is. By such adjustment, the current flowing through the switching element Q ₀ is adjusted, and as a result, the voltage across the smoothing capacitor C ₀ is kept almost constant. Incidentally, FIG. 16 (b) current flowing through the switching element Q _2, FIG. 16 (d) shows a current flowing through the switching element Q _0.

On the other hand, the lamp La₁, La_TwoDimmable lighting
(The same applies to preheating.)
The operating frequency of the road 1 is set higher than the rated lighting. Figure
17 shows the case where the operating frequency is set to 80 kHz.
doing. (A) to (d) of FIG. 17 are (a) to (d) of FIG.
As in (d), the inverter control signal and the switching element
Child Q_TwoCurrent, chopper control signal, switching
Element Q₀Shows the current flowing through each. Where inva
In addition to increasing the operating frequency of the
Reduce the on-duty of the bar control signal to 20%
The chopper control signal is
Are set equal. Inverter control signal
When the on-duty is set as described above,
Element Q ₁, Q_TwoCauses a difference in the on-duty. This
In the example, the switching element Q_TwoIn the ON period of
Capacitor C₁₁, C₁₂The discharge current of
Sensor C₁₁, C₁₂Surplus occurs in the charge of the switching element
Q₁Capacitor C during the ON period of₁₁, C₁₂Charge to
The current decreases. That is, the lamp La₁, La_TwoFlow
The lamp current is reduced. Thus, the operation
It is necessary to change not only the wave number but also the on-duty at the same time.
By performing dimming lighting or preheating with
When shifting from dimming to dimming, or starting from preheating
When the operation frequency is shifted to
The width of the change can be reduced. As a result,
The upper limit of the operating frequency of the data circuit 1 is suppressed to increase noise.
Can be suppressed. Note that the chopper control signal is turned on.
Since the duty is constant, the output voltage of DC power supply 1 is
To keep the inverter circuit 1 stable and stable
Can be. The frequency and on-duty in the illustrated example are
It shows an example, and it means that it can be set appropriately
Not even.

When the number of dimmed lights or the number of lights of the lamps La ₁ and La ₂ is reduced, the control may be performed as shown in FIG. Here, when the number of lights of the lamps La ₁ and La ₂ decreases (in the present embodiment, _two lamps La ₁ and La ₂ are shown, so that one lamp is turned on, and hereinafter, one lamp is turned on). ) Means that one of the lamps La ₁ and La ₂ is removed or separated from the circuit by a switch or the like. FIGS. 18 (a) to 18 (d) also show FIGS.
(D) the same manner, indicating the inverter control signal, a current flowing through the switching element Q _2, the chopper control signal, the current flowing through the switching element Q ₀ respectively. At the time of dimming lighting or single lamp lighting, the frequency of the inverter control signal is increased and the on-duty is reduced as in the control example described above. The difference from the above-described control example is that the on-duty of the chopper control signal is similarly reduced at this time. That is, at the time of dimming lighting or one lamp lighting, the power consumption of the inverter circuit 1 as a load of the DC power supply 2 is reduced as compared with the rated lighting, and the smoothing capacitor C
Since the discharge amount of ₀ is reduced, it is to reduce the amount of charge of by reducing the on-duty of the chopper control signal to the smoothing capacitor C _0. With such an operation, the energy balance of input and output is maintained. In the illustrated example, the frequency of the inverter control signal and the frequency of the chopper control signal are 80 kHz,
Although an example in which the on-duty is set to about 30% is shown, these may be set as appropriate.

The control examples shown in FIGS. 19 and 20 are effective control examples when one lamp is turned on or at the end of the life. The on-duty of the chopper control signal is adjusted without changing the on-duty of the inverter control signal. Things. FIG. 19, FIG.
0 of (a) ~ (d) show similar to FIG 16 (a) ~ (d) , the inverter control signal, a current flowing through the switching element Q _2, the chopper control signal, the current flowing through the switching element Q ₀ respectively . FIG. 19 shows the operation at the time of rated lighting, and is basically the same as the operation shown in FIG. 16 (that is, the operating frequency of the inverter circuit 1 is 50 kHz and the on-duty is 50%). The vertical stripes in FIG. 19C indicate the adjustment width of the on-duty of the chopper control signal, and the switching element Q _{0 is obtained} by such adjustment.
Is adjusted as shown by the hatched portion in FIG.

When one lamp is turned on or end of life, the lamp L
When the power supplied to a ₁ and La ₂ decreases and the load on the DC power supply 2 decreases, as shown in FIG. 20, the frequency of the reference signal output from the oscillation circuit 11 becomes higher (for example, 80 k).
Hz). Here, while the on-duty of the inverter control signal is kept as it is, the on-duty of the chopper control signal is reduced (for example, 30%). This control, the voltage across the smoothing capacitor C ₀ can be prevented from being abnormally increased.

In order to change the on-duty of the chopper control signal, any of the following configurations may be adopted. First, there is a configuration in which the on-duty is reduced as the frequency of the inverter control signal increases. Also, utilizing the fact that the on-duty of the chopper control signal is controlled by monitoring the voltage across the smoothing capacitor C ₀ in the chopper control circuit 13, the resistors R ₄₁ and R ₄₂ that divide the voltage across the capacitor C ₀ are used. The configuration may be such that the voltage division ratio (R ₄₁ / R ₄₂ ) is reduced or the reference voltage to be compared with the voltage across the capacitor C ₀ is increased. Also in this control example, the frequency and the on-duty can be set appropriately.
Other configurations and operations are the same as those of the second embodiment.

[0077]

Embodiment In each of the above-described embodiments, a half-bridge type inverter circuit 1 can be considered to have a configuration shown in FIG. The DC power supply 2 in FIG. 18 only needs to have a variable output voltage. For example, a chopper circuit as in the first embodiment or a rectifier circuit as in the third embodiment is used.

In this configuration, the lamps La ₁ and La ₂ are
When the combination of CL40W and FCL32W is used,
For the case where a set of 32W and FCL30W is used,
Table 1, respectively, a combination of one example of the inductor L _21, L ₂₂ and capacitor C _21, C ₂₂ constituting a resonance circuit, Table 2
Shown in

[0079]

[Table 1]

[0080]

[Table 2]

The output voltage of the DC power supply 2 is set so that the voltage between the ground measured as the voltage between one end of the AC power supply AC and one end of the output of the inverter circuit 1 does not exceed 300 V, and the power consumption ( Lamps La with different starting voltages)
_The voltage is set to a voltage which does not enter the phase advance region when the maximum starting voltage of ₁ and La ₂ is applied. Specifically 25
It is set to about 0V. In addition, inductors L ₂₁ and L ₂₂
Is determined by the rated current of each of the lamps La ₁ and La ₂ . Under such conditions, the lamp L
When the capacitors C ₂₁ and C ₂₂ are set so that the resonance frequencies of the resonance circuits of the pair of lamps La ₁ and La ₂ are set substantially equal in consideration of the starting voltages and the preheating currents of the a ₁ and La ₂ , respectively. 1, as shown in Table 2.

If the inverter circuit 1 is operated with a frequency higher than the resonance frequency of the resonance circuit set as described above as the operating frequency, operation in the phase advance region can be prevented, and the switching elements Q ₁ and Q ₂ Destruction can be prevented.

[0083]

According to the first aspect of the present invention, there is provided a DC power supply, an inverter circuit for converting the DC power supply output to a high frequency power, and a plurality of power consumption different power supplies connected in parallel to the output of the inverter circuit via a resonance circuit. A discharge lamp load, wherein the output voltage of the DC power supply is set so that the operating frequency of the inverter circuit for starting the discharge lamp load is kept in a phase lag region of the resonance frequency of the resonance circuit. In order to obtain the starting voltage of the inverter circuit, the operating frequency of the inverter circuit is maintained in the delay region of the resonance frequency of the resonance circuit by appropriately setting the voltage of the DC power supply which is the input to the inverter circuit. , Without the need for a special protection circuit to prevent destruction due to operation in the phase advance region,
There is an advantage that destruction of the inverter circuit can be prevented with a simple configuration. In particular, when starting and lighting a plurality of loads having different power consumptions with one inverter circuit, it is difficult to design the resonance circuit and set the operating frequency of the inverter circuit. There is an advantage that the design is facilitated because the setting is made by setting the voltage on the side.

According to the second aspect of the present invention, when the DC power supply is a step-up chopper circuit, the output voltage of the DC power supply can be easily controlled, and since the DC power supply is a step-up chopper circuit, the input to the inverter circuit is reduced. Therefore, there is an advantage that the voltage of the DC power supply is increased, and the starting voltage can be easily obtained. According to a third aspect of the present invention, the inverter circuit and the chopper circuit each include a switching element that switches at a high frequency, and include a control circuit that switches the switching elements of the inverter circuit and the DC power supply in conjunction with each other at the same frequency. In this case, since the operations of the inverter circuit and the chopper circuit are linked, there is an advantage that a part of the circuits can be commonly used for the control of the inverter circuit and the control of the chopper circuit, and the circuit configuration is simplified.

According to a fourth aspect of the present invention, the DC power supply includes a first rectifier circuit for performing full-wave rectification on the AC power supply, a second rectifier circuit for performing voltage double rectification on the AC power supply, and a first rectifier circuit. And switching means for selecting one of the outputs of the second rectifier circuit and the second rectifier circuit, the input voltage to the inverter circuit is switched between at the time of starting and at the time of steady lighting, so that there is an advantage that the voltage stress of the inverter circuit is small. is there.

According to a fifth aspect of the present invention, the inverter circuit has an output transformer between the discharge lamp load and the DC power supply is a series circuit of a feedback winding provided in the output transformer, an input power supply, an inductor, and a capacitor. With the output voltage of the smoothing capacitor connected to the series circuit of the feedback winding and the capacitor via a rectifier element, a part of the output energy is fed back to the input side via a transformer. Since the voltage across the smoothing capacitor can be boosted from the input power supply voltage by the action of the feedback winding, inductor, and capacitor, the voltage required for starting and lighting as in the case of using a boost type chopper circuit is reduced. It has the advantage of being easy to obtain, and can boost the voltage across the smoothing capacitor without using switching elements. Since that, there is an advantage that the circuit configuration is simpler than the case of using a chopper circuit.

According to a sixth aspect of the present invention, the inverter circuit includes a switching element that switches at a high frequency, a DC power supply is connected in series with the switching element, and a smoothing capacitor whose both-ends voltage is used as a power supply of the inverter circuit. When the switching element of the inverter circuit has at least one of an inductor and a backflow prevention element inserted in a path for discharging energy stored in the inductor when the switching element is on to the smoothing capacitor when the switching element is off, Since a part also functions as a switching element of a chopper circuit, there is an advantage that the number of switching elements can be reduced as compared with a case where a chopper circuit is provided.

According to a seventh aspect of the present invention, a resonance circuit is provided between each discharge lamp load and the inverter circuit.
When the resonance frequency of each resonance circuit is set to be almost equal, the operating frequency of the inverter circuit is set because the resonance frequency of the resonance circuit is almost equal while setting the characteristics of the resonance circuit according to each discharge lamp load. There is an advantage that it becomes easy.

In the case where the output voltage of the DC power supply is kept substantially constant irrespective of the operation of the inverter circuit, the output voltage of the DC power supply changes even if the operation of the inverter circuit changes. Is maintained constant, there is an advantage that it is possible to prevent an excessive voltage from being applied to the inverter circuit or an excessive current from flowing through the inverter circuit.

According to the ninth aspect of the present invention, the output voltage of the DC power supply is set to be higher in the order of the inverter circuit stop period, the discharge lamp load preheating period, the discharge lamp load start period, and the discharge lamp load lighting period. By setting the output voltage of the DC power supply according to each operation state of the inverter circuit, it is possible to prevent an excessive voltage from being applied to the inverter circuit or an excessive current from flowing through the inverter circuit. It has the advantage that it can be done.

According to a tenth aspect of the present invention, the control circuit comprises:
When the power is turned on, the chopper circuit is operated after the operation of the inverter circuit, and when the power is turned off, the inverter circuit is stopped after the chopper circuit is stopped.If the chopper circuit becomes lightly loaded, the output voltage of the chopper circuit rises abnormally. Can be prevented.

According to the eleventh aspect, the control circuit comprises:
When the power is turned on, the inverter circuit operates after the operation of the chopper circuit, and when the power is turned off, the chopper circuit stops after the inverter circuit stops. This has the advantage that unstable operation of the inverter circuit due to insufficient input voltage can be prevented. There is. According to a twelfth aspect of the present invention, the control circuit changes the on-duty of the switching element of the inverter circuit according to a change in the state of the discharge lamp load, and keeps the on-duty of the switching element of the chopper circuit constant. The output voltage of the circuit is almost constant, so that an excessive voltage is applied to the inverter circuit or an excessive current flows through the inverter circuit, and the on-duty of the switching element of the inverter circuit is reduced. There is an advantage that the power supply suitable for preheating and dimming of the discharge lamp load can be performed by changing.

According to a thirteenth aspect of the present invention, the control circuit comprises:
In the case where the on-duty of the switching element of the chopper circuit is changed in accordance with the change in the state of the discharge lamp load and the on-duty of the switching element of the inverter circuit is kept constant, the on-duty of the switching element of the chopper circuit is reduced when the load is light. The adjustment has the advantage that the output voltage of the chopper circuit can be prevented from rising abnormally.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention.

FIG. 2 is a circuit diagram showing the first embodiment.

FIG. 3 is a circuit diagram showing a second embodiment.

FIG. 4 is an operation explanatory view of the above.

FIG. 5 is a circuit diagram of the same.

FIG. 6 is a circuit diagram showing a third embodiment.

FIG. 7 is a circuit diagram showing a fourth embodiment.

FIG. 8 is a circuit diagram showing a fifth embodiment.

FIG. 9 is a circuit diagram showing a sixth embodiment.

FIG. 10 is a circuit diagram showing a seventh embodiment.

FIG. 11 is a circuit diagram showing an eighth embodiment.

FIG. 12 is an operation explanatory view of the above.

FIG. 13 is a circuit diagram showing a ninth embodiment.

FIG. 14 is a circuit diagram showing a tenth embodiment.

FIG. 15 is an explanatory diagram of the operation of the above.

FIG. 16 is an operation explanatory view of the above.

FIG. 17 is an operation explanatory view of the above.

FIG. 18 is an operation explanatory view of the above.

FIG. 19 is a diagram illustrating the operation of the above.

FIG. 20 is an explanatory diagram of the operation of the above.

FIG. 21 is a schematic configuration diagram illustrating an example of the present invention.

FIG. 22 is a circuit diagram showing a conventional example.

FIG. 23 is an explanatory diagram of the operation of the above.

[Explanation of symbols]

First inverter circuit 2 DC power supply 11 oscillation circuit 12 inverter control circuit 13 chopper control circuit AC AC power supply C ₀ smoothing capacitor C ₃ capacitors C _01, C ₀₂ capacitor C _21, C ₂₂ capacitor CN control circuit D ₀ diode D ₇ diode D ₈ diode DB rectifying circuit L ₀ inductor L ₃ inductor L ₇ inductor L _21, L ₂₂ inductor La _1, La ₂ lamps n ₃ feedback winding Q ₀ switching elements Q _1, Q ₂ switching elements SW ₀ change-over switch T ₁ output transformer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koji Fujimoto 1048 Kazuma Kadoma, Kadoma City, Osaka Inside Matsushita Electric Works, Ltd.

Claims (13)

[Claims] A DC power supply, an inverter circuit for converting an output of the DC power supply into high-frequency power, and a plurality of discharge lamp loads of different power consumption connected in parallel to the output of the inverter circuit via a resonance circuit; A discharge lamp lighting device, wherein an output voltage of a DC power supply is set such that an operation frequency of an inverter circuit for starting a discharge lamp load is maintained in a delay region of a resonance frequency of a resonance circuit. 2. The discharge lamp lighting device according to claim 1, wherein the DC power supply is a step-up chopper circuit. 3. The inverter circuit and the chopper circuit both include a switching element that is switched at a high frequency, and a control circuit that switches each of the switching elements of the inverter circuit and the DC power supply in conjunction with each other at the same frequency. The discharge lamp lighting device according to claim 2. 4. A DC power supply comprising: a first rectifier circuit for full-wave rectifying an AC power supply; a second rectifier circuit for rectifying the AC power supply by a double voltage; a first rectifier circuit and a second rectifier circuit; 2. A discharge lamp lighting device according to claim 1, further comprising a switching unit for selecting one of the outputs. 5. The inverter circuit includes an output transformer between the discharge lamp load and the DC power supply includes a series circuit including a feedback winding provided on the output transformer, an input power supply, an inductor, and a capacitor. 2. The discharge lamp lighting device according to claim 1, wherein a voltage between both ends of a smoothing capacitor connected to a series circuit of the capacitor and the capacitor via a rectifying element is used as an output voltage. 6. The inverter circuit includes a switching element that switches at a high frequency. The DC power supply includes a smoothing capacitor that uses a voltage between both ends as a power supply of the inverter circuit; an inductor connected in series with the switching element; 2. The discharge lamp lighting device according to claim 1, further comprising a backflow prevention element inserted in a path for discharging energy stored in the inductor when the switching element is turned on to the smoothing capacitor when the switching element is turned off. 7. A resonance circuit is provided between each discharge lamp load and an inverter circuit, and each resonance circuit has a resonance frequency set to be substantially equal.
The discharge lamp lighting device as described in the above. 8. The discharge lamp lighting device according to claim 1, wherein the output voltage of the DC power supply is kept substantially constant regardless of the operation of the inverter circuit. 9. The output voltage of the DC power supply is set to be higher in the order of a stop period of the inverter circuit, a preheating period of the discharge lamp load, a start period of the discharge lamp load, and a lighting period of the discharge lamp load. Item 10. The discharge lamp lighting device according to Item 1. 10. The discharge lamp lighting device according to claim 3, wherein the control circuit operates the chopper circuit after the operation of the inverter circuit when turning on the power, and stops the inverter circuit after stopping the chopper circuit when the power is turned off. . 11. The discharge lamp lighting device according to claim 3, wherein the control circuit operates the inverter circuit after the operation of the chopper circuit when turning on the power, and stops the chopper circuit after stopping the inverter circuit when the power is turned off. . 12. The control circuit according to claim 3, wherein the on-duty of the switching element of the inverter circuit is changed in accordance with a change in the state of the discharge lamp load, and the on-duty of the switching element of the chopper circuit is kept constant. The discharge lamp lighting device as described in the above. 13. The control circuit according to claim 3, wherein the on-duty of the switching element of the chopper circuit is changed in accordance with a change in the state of the discharge lamp load, and the on-duty of the switching element of the inverter circuit is kept constant. The discharge lamp lighting device as described in the above.