JPH10189274A - Power supply device, discharge lamp lighting device, and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device in which output can be properly controlled before or after lighting a discharge lamp without complicating a circuit constitution. SOLUTION: In the condition where a fluorescent lamp FL is not lighted, a pre-lighting switching control part 15 sets on-duty of a first and a second switching devices Q1, Q2 in preheating at about 80% and 20% respectively, so a relatively low voltage is applied to the fluorescent lamp FL. At completion, on-duty of the first and the second switching devices Q1, Q2 is set at about 70% and 30% respectively, so an output voltage set to be relatively high is applied to the fluorescent lamp FL. As the fluorescent lamp FL is lighted, on-duty of the first and the second switching devices Q1, Q2 is switched by PWM control within ranges of about 40-60% and about 60-40% respectively for setting an output voltage to be relatively high, thereby a proper voltage can be applied to the fluorescent lamp FL.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device, a discharge lamp lighting device, and a lighting device capable of properly lighting a discharge lamp before and after lighting the discharge lamp without complicating a circuit configuration.

[0002]

2. Description of the Related Art Hitherto, as a lighting apparatus of this kind, for example, a configuration described in Japanese Patent Application Laid-Open No. 8-98555 has been known.

In Japanese Patent Laid-Open Publication No. Hei 8-98555, a rectifier for performing non-smoothing rectification is connected to a commercial AC power supply, and the rectifier is alternately turned on at an output terminal of the rectifier at a frequency higher than the output frequency of the commercial AC power supply. A pair of switching devices connected in series to be turned off are connected, and a relatively large-capacity first capacitor and a second capacitor for resonance are connected, and between the pair of switching devices and the first capacitor. An inductor is connected in between, a discharge lamp is connected to the output side of the inductor, and a pair of switching devices are turned on and off at a substantially constant frequency by switching control means,
The input power factor is improved to reduce input distortion.

Further, the capacity of the first or second capacitor of the discharge lamp is made variable, and the output voltage is changed between before and after the discharge lamp is turned on, so that the discharge lamp is softened. I'm starting.

[0005]

However, in the configuration described in Japanese Patent Application Laid-Open No. 8-98555, the capacity of the first capacitor or the second capacitor is changed before and after lighting of the discharge lamp. In addition, the design of charging / discharging of the first capacitor or resonance with the second capacitor and the inductor becomes complicated, and there is a problem that control becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a power supply device and a discharge lamp lighting device capable of appropriately controlling output before and after lighting of a discharge lamp without complicating a circuit configuration. And a lighting device.

[0007]

According to a first aspect of the present invention, there is provided a power supply apparatus comprising: a rectifier for rectifying an output voltage of an AC power supply to output a non-smooth DC voltage; An inverter device thrown at the output side of the rectifier device; a load energized by the high-frequency output of the inverter device; an ingkta provided to store energy when the switching device of the inverter device is turned on; A smoothing capacitor that is charged by the stored energy of the inductor when the switching device that stores energy is turned off and supplies the charged charge to the inverter device; and that the switching device that stores energy in the inductor of the inverter device is turned on and off at a substantially constant frequency. In normal operation of the load, And Kikukatsu variable, at the time of non-stationary load is obtained by including a switching control means for relatively small and substantially constant on-duty. Then, the non-smoothing DC voltage of the rectifier is smoothed, the smoothing capacitor and the inductor generate a resonance voltage according to ON / OFF of the pair of switching devices, and the resonance voltage raises a valley of the non-smooth DC voltage, Smooths the envelope of the high-frequency output voltage. In addition, the input current is secured during the period in which the peak value of the unsmoothed DC voltage is low, the input power factor is increased, and the distortion of the input current is reduced to reduce harmonics of the input current. The switching control means turns on and off the switching device that stores energy in the inductor of the inverter device at a substantially constant frequency, makes the on-duty relatively large and variable during a steady operation of the load, and turns on when the load is not steady. Since the duty is relatively small and substantially constant, the output voltage is appropriate both before and after lighting of the discharge lamp.

According to a second aspect of the present invention, there is provided a power supply apparatus comprising: a rectifier for rectifying an output voltage of an AC power supply to output a non-smooth DC voltage; and a pair of switching units provided in series with each other and alternately turned on and off at a high frequency. An inverter provided on the output side of the output of the rectifier; a load energized by a high-frequency output of the inverter; and a storage for storing energy when one of the switching devices of the inverter is turned on. And a smoothing capacitor that is charged by the stored energy of the inductor when one of the switching devices is turned off, and supplies a charged charge to the inverter device; and that the switching device of the inverter device is turned on and off at a substantially constant frequency, During normal operation, the on-duty of one of the switching devices is relatively large and And then, during non-stationary operation of the load is obtained by including a switching control means for relatively small and substantially constant on-duty of one switching device. The switching device of the inverter device is turned on and off at a substantially constant frequency, and the on-duty of one of the switching devices is made relatively large and variable during a steady operation of the load. Is relatively small and substantially constant, so that the output voltage is appropriate both before and after lighting of the discharge lamp.

According to a third aspect of the present invention, there is provided a power supply device that rectifies an output voltage of an AC power supply and outputs a non-smoothed DC voltage; A pair of switching devices that alternately turn on and off at a frequency higher than the frequency; and a series circuit of a first capacitor and an inductor that smoothes the output frequency of a rectifier provided between both terminals of one of the switching devices. A second capacitor that resonates in cooperation with the inductor when the pair of switching devices is turned on and off;
An output circuit for outputting a high-frequency voltage based on the resonance of the inductor and the second capacitor to energize the load; turning on and off a pair of switching devices at a substantially constant frequency, and switching one of the switching devices during steady operation of the load. Switching control means for making the on-duty relatively large and variable, and for making the on-duty of one of the switching devices relatively small and almost constant when the load is in an unsteady operation. Then, the non-smoothing DC voltage of the rectifier is smoothed by the first capacitor,
The second capacitor and the inductor generate a resonance voltage according to the on / off of the pair of switching devices, and the resonance voltage lifts a valley of the non-smooth DC voltage and smoothes the envelope of the high-frequency output voltage. . The resonance voltage causes the voltage across the first capacitor and the second capacitor, or the voltage across the first capacitor, to be lower than the non-smoothing DC voltage of the rectifier during one cycle of switching of the pair of switching devices. Therefore, during one cycle of switching of the pair of switching devices, a charging current flows from the AC power supply to the first capacitor, and the charging current causes the input current to flow even during a period in which the peak value of the rectified non-smoothed DC voltage is low. While securing the input power factor, the input current is reduced to reduce the harmonics of the input current. In addition, the switching control means turns on and off the pair of switching devices at a substantially constant frequency, and can change the ratio of the on-period of the pair of switching devices. When the on-period is changed, the amplitude of the resonance voltage changes. However, if the ON period of one switching device is relatively increased, the value of the current flowing through the inductor before the resonance operation increases, the amplitude of the resonance voltage increases, and the output voltage is varied. Further, the switching means turns on and off the pair of switching devices at a substantially constant frequency, and makes the on-duty of one of the switching devices relatively large and variable during a steady operation of the load. Since the on-duty of the device is relatively small and substantially constant, the output voltage is appropriate both before and after the discharge lamp is turned on.

According to a fourth aspect of the present invention, in the power supply device according to any one of the first to third aspects, the switching control means has at least two types of switches for a normal operation and a non-stationary operation of the load. These are selectively operated according to the load state. By separately providing the load for the steady operation and the non-steady operation of the load, the respective structures are simplified.

According to a fifth aspect of the present invention, there is provided a discharge lamp lighting device comprising: the power supply device according to any one of the first to fourth aspects; and a discharge lamp energized by a high frequency voltage of the power supply device. It works.

According to a sixth aspect of the present invention, in the discharge lamp lighting device according to the fifth aspect, the switching control means of the power supply device turns on and off the switching device of the inverter device at a substantially constant frequency and discharges the discharge lamp. When the lamp is lit, the on-duty of the switching device that stores energy in the inductor is made relatively large and variable. When the electrode of the discharge lamp is pre-heated, the on-duty is relatively constant at the relatively low on-duty. The duty is made substantially constant. Then, the on-duty is made different when the discharge lamp is lit, when the electrode is preheated, and when the starting voltage is generated, so that the output voltage becomes appropriate before and after the discharge lamp is lit.

According to a seventh aspect of the present invention, in the discharge lamp lighting device according to the fifth and sixth aspects, the switching control means accumulates energy in the inductor in accordance with the output of the timer means. Then, energy is stored in the inductor according to the output of the timer means, so that the output voltage can be easily and appropriately adjusted.

According to an eighth aspect of the present invention, in the discharge lamp lighting device according to the fifth or sixth aspect, the switching control means detects a state of the discharge lamp and turns on a switching device for storing energy in the inductor. The duty is changed. Then, by changing the on-duty according to the state of the discharge lamp, the output voltage changes according to the state of the discharge lamp.

A discharge lamp lighting device according to a ninth aspect is the discharge lamp lighting device according to any one of the fifth to eighth aspects,
The switching control means enables dimmable lighting by changing the on-duty at the time of lighting of the discharge lamp. Then, dimming lighting is easily performed by changing the on-duty.

According to a tenth aspect of the present invention, there is provided the lighting device, wherein the lighting fixture body includes a discharge lamp supported by the lighting fixture body.
Or a discharge lamp lighting device according to any one of (1) to (9). Further, since the discharge lamp lighting device according to any one of claims 5 to 9 in which the discharge lamp is supported by the lighting fixture body, the respective functions are exerted.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a lighting device according to an embodiment of the present invention.

FIG. 1 is a circuit diagram showing a discharge lamp lighting device, FIG. 2 is a circuit diagram showing switching control means during lighting and switching control means before lighting, and FIG. 3 is a perspective view showing an appearance of the lighting device. 4 is a waveform diagram showing the relationship between the input voltage and the on-duty of the first switching device and the second switching device. FIG. 5 is a waveform diagram showing the relationship between the input voltage and the on-duty of the first switching device. FIG. 6 is a graph showing the relationship between the oscillation frequency and the output voltage.

As shown in FIG. 3, reference numeral 1 denotes an instrument main body, and the instrument main body 1 is a so-called trough type having a reflecting plate 2 formed on a surface thereof and attached to a ceiling surface (not shown) or the like. Further, a pair of lamp sockets 3 is disposed in the longitudinal direction at both ends of the reflection plate 2 of the apparatus main body 1, and a fluorescent lamp FL as a discharge lamp is mounted on these lamp sockets 3, and the inside thereof is shown in FIG. The illustrated discharge lamp lighting device 11 is housed.

As shown in FIG. 1, in the discharge lamp lighting device 11, a filter circuit 12 having a choke coil L1 and a capacitor C1 is connected to a commercial AC power supply e. The input terminal of the configured full-wave rectifier 13 of the diode bridge is connected.

Between the output terminals of the full-wave rectifier 13, a first switching device Q1 as one switching device and a second switching device Q2 as the other switching device are connected in series. Each of the first switching device Q1 and the second switching device Q2 has a field-effect transistor using a parasitic diode for reverse current conduction, and forms an inverter circuit 14 as a half-bridge type inverter device.

Further, between the output terminals of the full-wave rectifier 13, a first capacitor C2 for charging, which has a relatively large capacity, corresponds to the first switching device Q1 and the second switching device Q2, respectively. And the first capacitor C2
A second capacitor C3 for resonance having a much smaller capacity is connected in series.

The connection point between the first switching device Q1 and the second switching device Q2 and the connection point between the first capacitor C2 and the second capacitor C3 are shared with the second capacitor C3. The primary winding Tr1a of a leakage type insulation transformer Tr1 as an inductor which operates and oscillates is connected to the secondary winding Tr1b as an output circuit of the insulation transformer Tr1, and the filament FLa and the filament FLb of the fluorescent lamp FL are connected to the primary winding Tr1b of the insulation transformer Tr1. One end is connected and the filament FLa
A starting capacitor C4 is connected between the other end of the filament FLb. The insulation transformer Tr1 is
It also has the effect of the current limiting impedance of the fluorescent lamp FL.

The first switching device Q1 and the second switching device Q2 are respectively provided with a lighting-time switching control unit 15 as lighting-time switching control means and a pre-lighting switching control unit 16 as a lighting-time switching control means. Is controlled by When the first switching device Q1 and the second switching device Q2 are controlled, a period is provided in which one is turned off from on and the other is turned off when the other is turned on. It is not necessary.

The lighting-time switching control section
As shown in FIG. 2, the switching control unit 15 and the pre-lighting switching control unit 16 include a peak detection circuit 17 for detecting a peak of a switching current flowing through the first switching device Q1 or the second switching device Q2. Connect the resistor R1 to the circuit 17, connect the inverting input terminal of the operational amplifier OP1 to the resistor R1, connect the reference voltage source E1 to the non-inverting input terminal of the operational amplifier OP1, and output the parallel circuit of the capacitor C5 and the resistor R3. Connect between terminal and inverted input terminal.
The output terminal of the operational amplifier OP1 is connected to the input terminal of the AND circuit AND1 of the output terminal of the operational amplifier OP2. The output terminal of the AND circuit AND1 is connected to the input terminal of the OR circuit OR1, and the output terminal of the OR circuit OR1 is It is connected to a buffer 18.

Further, an OSC 19 is provided. The OSC 19 has a resistor R2 for setting the oscillation frequency to, for example, 50 kHz.
And the capacitor C6 are connected, a sawtooth voltage is output from the capacitor C6 side, and the non-inverting input terminals of the operational amplifiers OP2 and OP3 are connected to each other, and the operational amplifier OP3 is connected to the input terminal of the AND circuit AND2. . The oscillation frequency is set in inverse proportion to the product of the resistor R2 and the capacitor C6.

Further, a lighting detection circuit 21 which outputs a high level at the time of preheating and starting and outputs a low level at the time of lighting is connected to the input terminal of the AND circuit AND2, and the input terminal of the AND circuit AND2 is connected to the AND circuit via the inverter circuit INV1. AND1
Is connected to the input terminal of

On the other hand, a resistor R is connected between the power supply VCC and the ground.
4, the series circuit of resistor R5 and resistor R6 is connected,
The collector and the emitter of the transistor Q3 are connected between both ends of the transistor Q3. The base of the transistor Q3 is connected to the preheating end signal circuit 22 through the resistor R7.
22 outputs a high level at the time of preheating, and outputs a low level after the end of preheating.

Next, the operation of the above embodiment will be described.

First, the voltage of the commercial AC power supply e is input to the full-wave rectifier 13 via the filter circuit 12, and the full-wave rectifier 13 performs full-wave rectification. On the other hand, the first switching device
Q1 and the second switching device Q2 are oscillated at a frequency higher than the power supply frequency of the commercial AC power supply e, several kHz or more, preferably 20 kHz or more which is higher than the audible frequency, and a high-frequency AC voltage is applied to the secondary winding Tr1b of the insulating transformer Tr1. And the fluorescent lamp FL is turned on.

Further, a resonance voltage is generated by the second capacitor C3 and the isolation transformer Tr1.
Even during a period in which the peak value of the voltage rectified by the full-wave rectifier 13 is low, a current flows from the commercial AC power supply e to achieve a high power factor and low distortion.

More specifically, first, in a state where the first capacitor C2 is charged, the first switching device
When Q1 is closed, the first capacitor C2, the isolation transformer Tr
1 forms a closed circuit of the primary winding Tr1a, the first switching device Q1 and the first capacitor C2,
C2 discharges.

Next, since the first switching device Q1 is turned off and the second switching device Q2 can conduct reverse current, the primary winding Tr1a of the insulating transformer Tr1, the second switching device Q2, and the second Capacitor C3 and isolation transformer Tr
1 is closed, and the isolation transformer Tr1
In addition, a series resonance occurs in the second capacitor C3, and a resonance current flows. Then, a resonance voltage appears in the second capacitor C3 and the primary winding Tr1a of the insulating transformer Tr1, and the resonance voltage is determined by the magnitude of the current that is cut off when the first switching device Q1 is turned off, It also appears at the voltage of the full-wave rectifier 13 equal to the sum of the voltage of the second capacitor C3 and the voltage of the first capacitor C2.

When the second switching device Q2 is turned on, the second capacitor C3 and the second switching device Q2 are turned on.
2. A closed circuit is formed between the primary winding Tr1a of the insulating transformer Tr1 and the second capacitor C3, the polarity of the resonance current is inverted, and a resonance current in the opposite direction flows, thereby generating a resonance voltage. In any case, the resonance voltage increases the pulsating voltage.

The primary winding Tr1a of the insulating transformer Tr1
When the resonance voltage due to the second capacitor C3 decreases, the voltage across the second capacitor C3 and the first capacitor C2 also decreases, so that the primary voltage of the full-wave rectifier 13, the second switching device Q2, and the isolation transformer Tr1 is reduced. Winding Tr1a, 1st
And the full-wave rectifier 13 is closed, and the first capacitor C2 is charged.

Also, since the second switching device Q2 is turned off and the reverse current of the first switching device Q1 can flow, the primary winding Tr1a of the insulating transformer Tr1, the first capacitor C2, the first switching device Device Q1 and isolation transformer Tr
1 is closed, and the isolation transformer Tr1
A current flows through the primary winding Tr1a.

Then, the second switching device Q2 is turned on again.

Of these operations, in the portion where the peak value of the input voltage of the full-wave rectifier 13 shown in FIG. 4A is high, the first switching device Q1 is connected as shown in FIG. 4B.
FIG.
As shown in FIG. 4C, the on-duty of the second switching device Q2 is relatively shortened, and in the portion where the peak value of the input voltage is low, the on-duty of the first switching device Q1 is turned on as shown in FIG. Fig. 4
As shown in (c), the on-duty of the second switching device Q2 is made relatively long. The change in the on-period is not limited to being continuous with respect to the peak value, and may be stepwise.

As described above, when the on-period of the second switching device Q2 is relatively lengthened in the portion where the peak value is low, the amplitude of the resonance voltage and the peak value are increased.
This is larger than when the on-period of Q2 is relatively short. That is, in a portion where the peak value of the unsmoothed DC voltage is low, the voltage charged in the second capacitor C3 decreases according to the peak value, and the initial current flowing into the second capacitor C3 increases. Therefore, in the period where the peak value of the non-smoothed DC voltage is low, the voltage can be boosted more than in the portion where the peak value is high.

In the period where the peak value is low, the current flowing through the first switching device Q1 is cut off at a relatively small stage, so that the initial resonance current value after the first switching device Q1 is turned off is reduced. Although the resonance voltage is increased due to the charging voltage of the second capacitor C3, the peak voltage of the non-smooth DC voltage is reduced without excessively increasing the voltage at the valleys, although the resonance voltage is increased. During the period,
The voltage can be boosted as desired, and the output voltage can be smoothed.

Furthermore, since the current from the full-wave rectifier 13 flows over the entire period of the unsmoothed DC voltage, this current increases the input power factor and lowers the input current. The high frequency component of the input current is removed by the filter circuit 12.

In the current of the fluorescent lamp FL, low frequency ripple is reduced.

On the other hand, in the preheating or starting state before the fluorescent lamp FL is turned on, the fluorescent lamp FL becomes a light load and becomes an overcurrent and an overvoltage. Therefore, in the preheating or starting state before the fluorescent lamp FL is turned on, the output is not increased. Control. That is, the frequency is always constant in both preheating and starting lighting,
When the duty ratio is changed in the same way as the normal lighting state,
Since the current and voltage become higher than necessary due to the light load, the output voltage is controlled by setting the duty ratio to a predetermined constant value and controlling the frequency to be constant during preheating or starting.

First, when the fluorescent lamp FL is not lit, both the lighting detection circuit 21 and the preheating end signal circuit output a high level signal, and since the resistor R4 is in a bypass state, the operational amplifier OP3 outputs the output voltage. Is higher and O
Since the threshold for the sawtooth wave of SC19 is high, the operational amplifier OP2 outputs a relatively short pulse, and the buffer 18 increases the on-duty of the first switching device Q1,
For example, switching is performed with an on-duty of about 80% and a small on-duty of the second switching device Q2, for example, about 20%, and a voltage is applied to the fluorescent lamp FL at a relatively low voltage. The lighting detection circuit 21
Output high level, the inverter circuit INV1
, A low level is input to the AND circuit AND1, and the AND circuit AND1 maintains a low level output.

When the preheating of the fluorescent lamp FL is completed,
The preheating end signal circuit 21 becomes low level and the transistor
Since Q3 is turned off and the resistor R4 is no longer bypassed, the output voltage of the operational amplifier OP3 becomes slightly lower, and the threshold value for the sawtooth wave of the OSC19 becomes slightly lower.
2 outputs a slightly longer pulse, and the buffer 18 reduces the on-duty of the first switching device Q1 slightly, for example, the on-duty is about 70%,
Switching is performed with the on-duty of Q2 somewhat large, for example, about 30% on-duty, the output voltage is slightly increased, and a voltage is applied to the fluorescent lamp FL to start. In this case as well, when the lighting detection circuit 21 outputs a high level, the AND circuit is connected via the inverter circuit INV1.
A low level is input to AND1, and the AND circuit AND1 maintains a low level output.

As described above, the on-duty of the first switching device Q1 should be set to a constant value of 50% or more in both the preheating before the fluorescent lamp FL is turned on and the starting. Accordingly, it is possible to prevent an increase in output due to a light load without the fluorescent lamp FL being turned on.

Further, when the fluorescent lamp FL is turned on, the lighting detection circuit 21 outputs a low level output, the AND circuit AND2 outputs a low level, and the AND circuit AND1 outputs the output of the OSC19. 40%
６０60%, the on-duty of the second switching device Q2 is increased, for example, the output voltage is slightly increased by PWM control for controlling the on-duty in the range of about 60% to 40%, and the appropriate voltage is set to the fluorescent lamp FL. And harmonics can be reduced.

On the other hand, for example, the first
Switching device Q1 and second switching device Q2
By controlling the on-duty, the output voltage can be changed,
Dimmable lighting of fluorescent lamp FL. That is, when the on-duty of the second switching device Q2 is relatively increased, the output voltage increases, and when the on-duty is relatively reduced, the output voltage decreases, and the fluorescent lamp FL can be dimmed. The degree of dimming at this time, that is, (maximum on-time-minimum on-time) / switching cycle is the fifth.
As shown in the figure, control is performed so as to be kept constant during dimming as well as during normal lighting.

When the power is turned on, the first capacitor
The inrush current to C2 is that the primary winding Tr1a of the isolation transformer Tr1 is connected in series to the first capacitor C2, and that the second switching device Q2 is turned on and off at a high frequency. Thus, it is reduced.

When the duty ratio of the first switching device Q1 is reduced, the output voltage increases as shown in FIG. 6, and when it is increased, the output voltage decreases.

The on-duty is varied in synchronization with the pulsating voltage rectified by the full-wave rectifier circuit 13.

Next, another embodiment will be described with reference to FIG.

FIG. 7 is a circuit diagram showing a discharge lamp lighting device according to another embodiment. In the discharge lamp lighting device according to the embodiment shown in FIG. And a switching means 23 is formed.

The basic operation is the same as that of the discharge lamp lighting device 11 shown in FIG. 1, but before lighting of the fluorescent lamp FL, the lighting detection means 21 outputs a high level before lighting and performs switching before lighting. The operation of the control unit 16 is output from the AND circuit AND2, the lighting detection circuit 21 outputs a low level after lighting after lighting, and the operation of the switching control unit 15 during lighting is output from the AND circuit AND1, lighting before lighting. After the lighting, the operation is performed by the output of the switching control unit 15 during lighting.

Another embodiment will be described with reference to FIG.

FIG. 8 is a circuit diagram showing a discharge lamp lighting device according to another embodiment. In the discharge lamp lighting device according to the embodiment shown in FIG. 7, a lighting detection circuit 24 serving as lighting detection means is based on current detection. The filament of the fluorescent lamp FL
The primary winding CT of the current transformer CT1 is connected to both ends of FLb.
1a and a secondary winding CT1b as an output circuit are connected, and a lighting detection circuit 23 is connected to a tertiary winding CT1c of a current transformer CT1.

Although the basic operation is the same as that of the discharge lamp lighting device 11 shown in FIG. 7, when the fluorescent lamp FL is not lit, the currents flowing through the primary winding CT1a and the secondary winding CT1b are equal. No current flows through the tertiary winding CT1c, but after lighting, the current flowing through the primary winding CT1a is much larger than the current flowing through the secondary winding CT1b. Lighting is detected, and operation is performed by the output of the before-lighting switching control unit 16 before lighting and by the output of the lighting-time switching control unit 15 after lighting.

Further, another embodiment will be described with reference to FIG.

FIG. 9 is a circuit diagram showing a discharge lamp lighting device according to still another embodiment. In the discharge lamp lighting device according to the embodiment shown in FIG.
The FL is provided with an overvoltage detection circuit 25 as overvoltage detection means for detecting a voltage between both ends.

The basic operation is the same as that of the discharge lamp lighting device 11 shown in FIG. 7, but at normal voltage, the overvoltage detection circuit 25 outputs a low level, and the operation of the lighting switching control unit 15 is ANDed. Output from the circuit AND1, the overvoltage detection circuit 25 outputs a high level at the time of overvoltage detection, and outputs the operation of the switching control unit 16 before lighting from the AND circuit AND2. When an overvoltage is detected, the operation is performed by a low output of the switching control section 16 before lighting.

Still another embodiment will be described with reference to FIG.

FIG. 10 is a circuit diagram showing a discharge lamp lighting device according to still another embodiment. In the discharge lamp lighting device according to the embodiment shown in FIG. 9, the discharge lamp lighting device according to the embodiment shown in FIG. , The overvoltage detection circuit 25 detects the voltages of the first switching device Q1 and the second switching device Q2.

Another embodiment will be described with reference to FIG.

FIG. 11 is a circuit diagram showing a discharge lamp lighting device according to another embodiment. In the discharge lamp lighting device according to the embodiment shown in FIG. 2, an overcurrent detection circuit 26 is provided. 26 is connected to the base of a transistor Q4 via a resistor R8, the emitter of the transistor Q8 is installed, a capacitor C7 is connected between the base and the emitter, and a filter is formed by the resistor R8 and the capacitor C7. Further, an OR circuit OR2 is connected between the OR circuit OR1 and the buffer 18.
The collector of transistor Q4 is a resistor R9 and a capacitor
Connected to the power supply VCC through the parallel circuit of C8, and connected to the first switching device Q1 through the inverter circuit INV2.
And the input terminal of an OR circuit OR2 connected between the second switching device Q2.

On the other hand, the overcurrent detection circuit 26 is connected to the negative side of the first capacitor C2. In this way, by connecting the negative electrode of the first capacitor C2, the detection of the ground potential can be performed, and the configuration can be simplified.

When the overcurrent detection circuit 26 does not detect an overcurrent, the transistor Q4 is off, and the inverter circuit INV2 outputs a low level signal to the OR circuit OR2. The output of circuit OR1 is output as it is.

On the other hand, when the overcurrent detection circuit 26 detects an overcurrent, the transistor Q4 is turned on, so that the inverter circuit INV2 causes no substantial rectangular wave voltage to appear in the buffer 18, and the first switching device Q1 The second switching device Q2 is turned off at a duty of 100% to protect it from overcurrent.

In FIG. 11, the same effect can be obtained by connecting an overvoltage detection circuit 25 instead of the lighting detection circuit 21.

Further, by setting the time constants of the capacitor C8 and the resistor R9 to about the operating frequency, the voltage of the collector of the transistor Q4 returns to VCC every cycle. Returning to the operating state, if the overcurrent state is not avoided, the overcurrent detection circuit 26 operates almost every cycle to protect against overcurrent.

The overcurrent detection circuit 26 may be connected to the connection point between the first switching device Q1 and the second switching device Q2 on the side of the second switching device Q2.

Note that the current detection circuit 26 is a full-wave rectifier 1
3, the second switching device Q2, the primary winding Tr1a of the isolation transformer Tr1, the first capacitor C2 and the full-wave rectifier 13
The same effect can be obtained by providing it at any position on the path.

The same effect as in the above embodiment can be obtained even if the connection positions of the first switching device Q1 and the second switching device Q2 are reversed. In this case, the respective switching devices for controlling the ON period are also reversed.

In the above embodiment, the configuration using the field effect transistor has been described. However, a switching element having no parasitic diode, such as a bipolar transistor, can be similarly configured. When used, a diode whose conduction direction is reversed may be connected between the collector and the emitter, or when a diode is connected between the emitter and the base, this diode may be used.

Further, the same effect can be obtained by using not only an insulating transformer but also an autotransformer or a coil.

Next, another embodiment will be described with reference to FIG.

FIG. 12 is a circuit diagram showing a discharge lamp lighting device according to another embodiment. The discharge lamp lighting device shown in FIG.
The capacitor C11 and inductor L11 are connected to the commercial AC power supply e.
The input terminal of the full-wave rectifier circuit 31 is connected to the input terminal of the full-wave rectifier circuit 31 via a filter circuit, and a transistor Q11 as a switching device is connected to the output terminal side of the full-wave rectifier circuit 31 via an inductor L12. And a series circuit of a smoothing capacitor C12.
Note that the transistors Q11 and Q12
Inverter circuit 32 is formed by, for example, transistor Q1
The transistor 1 and the transistor Q12 have a diode D11 and a diode D12 for feedback, respectively, and a buffer 18 shown in FIG. A series circuit of capacitors C13 and C14 is connected in parallel with the capacitor C12, and the connection point of the transistors Q11 and Q12 is
The primary winding Tr1a of the magnetic flux leakage type isolation transformer Tr1 is connected to the connection point of C13 and the capacitor C14, and the secondary winding
The fluorescent lamp FL is connected to Tr1b.

When the voltage of the commercial AC power supply e is rectified by the full-wave rectifier circuit 31, the capacitor C12 is connected to the inductor L1.
2 and charged through diodes D11 and D12. In addition, the transistor Q11 and the transistor Q12 are alternately turned on and off by the output from the buffer 18 to induce a voltage in the secondary winding Tr1b of the insulating transformer Tr1 to turn on the fluorescent lamp FL. As for the control of the transistors Q11 and Q12, FIG.
As in the embodiment shown in FIG. 1, if the on-duty is changed while the frequency is kept constant, the steady state, which is the normal lighting state, or the unsteady state such as starting, electrode preheating, overvoltage state or overcurrent state, etc. The output can be set appropriately at all times.

As the load, any load such as a discharge lamp or arc welding can be used.

As described above, the steady operation refers to a stable state after the fluorescent lamp FL is turned on, and the non-steady state refers to a state when the fluorescent lamp FL is started, when the electrodes are preheated, when an overvoltage or an overcurrent occurs. The status such as time is included.

[0080]

According to the power supply device of the first aspect, the switching control means turns on and off the switching device that stores energy in the inductor of the inverter device at a substantially constant frequency, and reduces the on-duty during steady operation of the load. Since the duty is relatively large and variable, and the on-duty is relatively small and substantially constant when the load is not steady, the output voltage can be appropriately set before and after the discharge lamp is lit.

According to the power supply device of the second aspect, the switching device of the inverter device is turned on and off at a substantially constant frequency, and the on-duty of one of the switching devices is made relatively large and variable during steady operation of the load. During unsteady operation of the load, the on-duty of one of the switching devices is relatively small and substantially constant, so before and after lighting the discharge lamp,
Output voltage can be adjusted appropriately.

According to the power supply device of the third aspect, the switching means turns on and off the pair of switching devices at a substantially constant frequency, and increases the on-duty of one of the switching devices during the steady operation of the load. Since the on-duty of one of the switching devices is relatively small and substantially constant when the load is in an unsteady operation, the output voltage can be appropriately set before and after the discharge lamp is turned on.

According to the power supply device of the fourth aspect, in addition to the power supply device of any one of the first to third aspects, the switching control means includes at least two types of switches for a normal operation and a non-stationary operation of the load. Therefore, by separately providing each of the load for the steady operation and the non-steady operation of the load, the respective structures can be simplified.

According to the discharge lamp lighting device of the fifth aspect,
A discharge lamp energized by the high-frequency voltage of the power supply device according to any one of claims 1 to 4 has the respective effects.

According to the discharge lamp lighting device of the sixth aspect,
In addition to the discharge lamp lighting device according to claim 5, the on-duty is made different at each of the lighting of the discharge lamp, the preheating of the electrodes, and the generation of the starting voltage. Can be properly.

According to the discharge lamp lighting device of the seventh aspect,
In addition to the discharge lamp lighting device according to the fifth and sixth aspects, the switching control means accumulates energy in the inductor according to the output of the timer means, so that the output voltage can be easily and appropriately adjusted.

According to the discharge lamp lighting device of the eighth aspect,
In addition to the discharge lamp lighting device according to claim 5 or 6, the switching control means detects the state of the discharge lamp and changes the on-duty of the switching device that accumulates energy in the inductor. By changing the on-duty, the output voltage can be changed according to the state of the discharge lamp.

According to the discharge lamp lighting device of the ninth aspect,
In addition to the discharge lamp lighting device according to any one of claims 5 to 8, the switching control means enables dimmable lighting by changing the on-duty when the discharge lamp is turned on. Dimmable lighting is easy.

According to the certifying device of the tenth aspect, since the lighting fixture body is provided with the discharge lamp lighting device of any one of the fifth to ninth aspects in which the discharge lamp is supported, the respective effects can be obtained. it can.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram showing a lighting-time switching control means and a pre-lighting switching control means;

FIG. 3 is a perspective view showing an appearance of the lighting device.

FIG. 4 is a waveform chart showing a relationship between the input voltage and the on-duties of the first switching device and the second switching device.

FIG. 5 is a waveform chart showing a relationship between the input voltage and the on-duty of the first switching device.

FIG. 6 is a graph showing a relationship between an on-duty and an output voltage of the first switching device;

FIG. 7 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the present invention.

FIG. 8 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the present invention.

FIG. 9 is a circuit diagram showing a discharge lamp lighting device according to still another embodiment of the present invention.

FIG. 10 is a circuit diagram showing a discharge lamp lighting device according to still another embodiment of the present invention.

FIG. 11 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the present invention.

FIG. 12 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Appliance main body 11 Discharge lamp lighting device 13 Full-wave rectifier device 14, 32 Inverter circuit as an inverter device 15 Switching control unit during lighting as switching control unit during lighting 16 Switching control unit before lighting as switching control unit before lighting C2 1 capacitor C3 2nd capacitor e Commercial AC power supply FL Fluorescent lamp as discharge lamp Q1, Q2 Switching device Q11, Q12 Transistor Tr1 as switching device Insulation transformer Tr1b as inductor Inductor Secondary winding as output circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Keiichi Shimizu 4-3-1 Higashi Shinagawa, Shinagawa-ku, Tokyo Toshiba Lighting & Technology Corporation

Claims (10)

[Claims] 1. A rectifier for rectifying an output voltage of an AC power supply to output a non-smooth DC voltage; and an inverter device having at least one switching device for turning on and off at a high frequency, and being provided to an output side of the rectifier. A load energized by the high-frequency output of the inverter device; an incubator provided to store energy when the switching device of the inverter device is on; and an accumulation of inductor when the switching device that stores energy in the inductor is off. A smoothing capacitor that is charged by energy and supplies the charge to the inverter device; and a switching device that stores energy in the inductor of the inverter device is turned on and off at a substantially constant frequency, and has a relatively large on-duty during steady operation of the load. Variable and on when load is unsteady Switching control means for making the duty relatively small and substantially constant; and a power supply device. 2. A rectifier comprising: a rectifier for rectifying an output voltage of an AC power supply to output a non-smooth DC voltage; and a pair of switching devices provided in series and alternately turned on and off at a high frequency. An inverter device provided on the output side of the output of the inverter device; a load energized by a high-frequency output of the inverter device; an inductor provided to store energy when one of the switching devices of the inverter device is turned on; A smoothing capacitor that is charged by the energy stored in the inductor when the switching device is turned off and supplies the charged electric charge to the inverter device; Make the on-duty relatively large and variable,
Switching control means for making the on-duty of one of the switching devices relatively small and substantially constant during an unsteady operation of the load. 3. A rectifier for rectifying an output voltage of an AC power supply and outputting a non-smooth DC voltage; provided in series between output terminals of the rectifier, alternately at a frequency higher than an output frequency of the rectifier. A pair of switching devices that are turned on and off; a series circuit of a first capacitor and an inductor that smoothes an output frequency of a rectifier provided between both terminals of one of the switching devices; A second capacitor that resonates in cooperation with the inductor when turned off; an output circuit that outputs a high-frequency voltage based on the resonance of the inductor and the second capacitor to energize the load; It turns on and off at a substantially constant frequency and makes the on-duty of one switching device relatively large and variable during steady operation of the load. Switching control means for making the on-duty of one of the switching devices relatively small and substantially constant during an unsteady operation of the load. 4. The switching control means has at least two types, one for a steady operation of the load and one for an unsteady operation of the load.
The power supply device according to any one of claims 1 to 3, wherein these are selectively operated according to a load state. 5. A discharge lamp lighting device, comprising: the power supply device according to claim 1; and a discharge lamp energized by a high-frequency voltage of the power supply device. 6. The switching control means of the power supply device turns on and off the switching device of the inverter device at a substantially constant frequency, and sets the switching device for storing energy in the inductor when the discharge lamp is lit to have a relatively large on-duty. 6. The discharge lamp lighting device according to claim 5, wherein the discharge lamp lighting device is variable and is substantially constant at a relatively low on-duty when the discharge lamp electrode is preheated, and is substantially constant at a relatively intermediate on-duty when a starting voltage is generated. . 7. The discharge lamp lighting device according to claim 5, wherein the switching control means changes the on-duty of the switching device that stores energy in the inductor in accordance with the output of the timer means. 8. The discharge lamp lighting device according to claim 5, wherein the switching control means changes the on-duty of the switching device that stores energy in the inductor by detecting a state of the discharge lamp. 9. The discharge lamp lighting device according to claim 5, wherein the switching control means enables dimmable lighting by changing an on-duty when the discharge lamp is turned on. 10. A lighting device, comprising: a lighting fixture main body; and the discharge lamp lighting device according to claim 5, wherein a discharge lamp is supported by the lighting fixture main body.