JP2001103767A - Power supply device, discharge lamp lighting device and lighting device - Google Patents

Abstract

(57) [Summary] Conventionally, a voltage between a control pole and a main pole of a switching device is suppressed to a certain value or less by providing a constant voltage element. However, the conventional device has a slight problem in that it is inconvenient when the driving portion of the switching device is to be integrated into an IC. For this reason, an object is to provide a power supply device, a discharge lamp lighting device, and a lighting device that are also suitable for being integrated. An output of a feedback means (14) of a drive circuit (13) is applied as a drive voltage to each of switching devices (6, 7), and the switching devices are turned on and off alternately. Current control means 15
Suppresses a current value supplied to each switching device to a predetermined value or less. Therefore, the voltage applied between the control pole and the main pole of the switching device is also suppressed to a predetermined value or less. The current control means has a higher I.sub.
C conversion is easy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply, a discharge lamp lighting device, and a lighting device which mainly include a voltage-driven semiconductor switching device and convert a DC voltage into an AC voltage.

2. Description of the Related Art Conventionally, this type of apparatus has been disclosed in JP-A-8-23.
No. 6287 has been proposed. This one is
A pair of voltage-driven switching devices connected in series with each other are alternately turned on and off, and the discharge lamp is to be turned on at a high frequency based on the switching output obtained by these switching devices.

In this prior art, a secondary winding is provided in a current transformer provided in series with a discharge lamp, and a pair of switching devices are alternately turned on and off by an output voltage of the secondary winding. . In order to prevent the voltage from the secondary winding from being applied as an excessive voltage between the control pole and the main pole of the voltage-driven switching device, a constant voltage element is provided for each switching device. .

In the prior art, the voltage between the control pole and the main pole of the switching device is suppressed to a certain value or less by providing a constant voltage element. Therefore,
In terms of protection of the switching device, it is quite satisfactory. However, the conventional device has a slight problem in that it is inconvenient when the driving portion of the switching device is to be integrated into an IC. That is, it is not only impossible to make the constant voltage element itself into an IC, but it is also difficult to make a constant voltage circuit that requires some reference voltage value into an IC. For this reason, when considering the drive part as an integrated circuit, the design is performed without the constant voltage element or the constant voltage circuit, and the integrated circuit is half-finished. Or I including a constant voltage element or a constant voltage circuit.
There is a problem in that an attempt to convert to C requires a special design, resulting in a high price.

The present invention provides a power supply device and a discharge lamp lighting device which can prevent an excessive voltage from being applied between a control pole and a main pole of a switching device and which can easily cope with an IC. It is an object to provide a device and a lighting device.

According to a first aspect of the present invention, there is provided a power supply apparatus comprising: a DC power supply; and a pair of voltage-driven switching units for inputting a DC voltage of the DC power supply and alternately turning on and off the DC voltage. A load circuit that is supplied with a switching output of the switching device and supplies an AC voltage to the load; and a feedback unit that generates a voltage corresponding to the AC voltage supplied to the load, and outputs the output of the feedback unit to each switching device. And a current control means provided in the drive circuit to control a current value supplied to each switching device for on / off control to a predetermined value or less. Features.

[0004] In the first and second aspects of the present invention, each configuration, term, and the like are defined as follows. The voltage-driven switching device is typically a field-effect transistor, but is not limited to this and allows the same type. And the switching device is of a type connected in parallel to the input DC power supply device,
Any type connected in series may be used, and two or more pairs may be provided.

[0005] The load circuit is supplied with a switching output of a switching device and supplies an AC voltage to the load. Such a load circuit may include, for example, an LC resonance circuit. In this case, a sinusoidal AC voltage can be generated, which is extremely effective in reducing high-frequency noise. However, a voltage having a waveform other than a sinusoidal voltage such as a rectangular voltage may be generated, and the present invention is not particularly limited. The load circuit may also energize the discharge lamp as a load. In this case, a current limiting impedance element for stably lighting the discharge lamp, a filament preheating circuit, and the like are included. Since various types of such load circuits themselves are well known and can be appropriately configured by those skilled in the art, these can be appropriately adopted in the present invention.

[0006] The drive circuit needs to include at least feedback means, but may or may not include other components. The feedback means may be common to each switching device or may be provided specially. Such return means include:
A transformer, a current transformer, a device using a photocoupler, or the like can be used. As an example, the current control means can be mainly composed of a switching element having a constant current characteristic, for example, a junction field effect transistor, but may be another known constant current circuit or the like.
C-constant current means may be used. The current control means may be provided in common for each switching device or may be provided individually, and this is determined to some extent by the configuration of the drive circuit.

[0007] The switching frequency of the switching device is not particularly limited, but is preferably not lower than the audible frequency and is not lower than 20 KHz from the viewpoint that the luminous efficiency can be increased.

According to the first aspect of the present invention, the output of the feedback means of the drive circuit is applied as a drive voltage to each switching device, and the switching devices are turned on and off alternately. The current control means suppresses a current value supplied to each switching device to a predetermined value or less. Therefore, the voltage applied between the control pole and the main pole of the switching device is also suppressed to a predetermined value or less.

A power supply device according to a second aspect of the present invention includes: a DC power supply device; at least a pair of voltage-driven switching devices that input a DC voltage of the DC power supply device and alternately turn on and off to switch the DC voltage; A load circuit having an inductor and a capacitor for resonance, receiving a switching output to generate a resonance voltage, and supplying the resonance voltage to a load;
Feedback means for generating a voltage corresponding to the AC voltage supplied to the load, including a resonance circuit resonating with the output voltage of the feedback means,
A drive circuit for applying the output of the resonance circuit to each switching device as an on / off drive voltage; and current control means provided to control the current of the resonance circuit of the drive circuit to a predetermined value or less. It is characterized by. A discharge lamp lighting device according to a third aspect includes a power supply device according to the first or second aspect; and a discharge lamp energized by a load circuit as a load of the power supply device. Lighting device. It is characterized by having. The present invention is applicable to discharge lamps having a possibility of exhibiting a striation phenomenon, such as a hot cathode fluorescent lamp, a cold cathode fluorescent lamp, and a rare gas discharge lamp. The lighting device according to claim 4 includes a lighting fixture main body; a discharge lamp lighting device according to any one of claims 1 to 5; and a discharge lamp that is turned on by the discharge lamp lighting device. Features.

In the invention of claim 4, the lighting fixture body may be for indoor or outdoor use, and may be for general lighting, display, OA equipment, or the like. Further, it may or may not have a light control body such as a reflector or a light shielding body, and may have a light bulb shape. Further, the discharge lamp lighting device may or may not be housed in the lighting fixture body.

According to the fourth aspect of the present invention, there is provided an illumination device having the same function as the first aspect of the present invention.

Next, one embodiment of the present invention will be described.

FIG. 1 is a circuit diagram showing one embodiment of the present invention.
FIG. 2 is a current and voltage waveform diagram showing the operation of the embodiment of FIG. Reference numeral 1 denotes a DC power supply, which is obtained by rectifying a commercial power supply voltage, a battery, and the like. In the present embodiment, it is connected to the AC power supply 2 via a current fuse, a high-frequency cut filter 3, etc. provided as necessary. Further, although the DC power supply device 1 has, for example, the rectifier 4 and the smoothing capacitor 5, a low distortion smoothing circuit (not shown) such as an active filter may be used instead of the simple smoothing capacitor 5. Reference numerals 6 and 7 denote a pair of voltage-driven switching devices connected in series to each other. In the present embodiment, they are field effect transistors. The switching devices 6 and 7 are alternately turned on and off to switch the DC voltage of the DC power supply 1. 8 is a load circuit. The load circuit 8 includes a switching device 7
, And includes a resonance inductor 9, a resonance capacitor 10, and a DC cut capacitor 11 in series. A load 12 is, for example, a discharge lamp, and is provided in parallel with the resonance capacitor 10. In the present embodiment, the resonance inductor 9 also acts as a current limiting impedance of the load 12, and the resonance capacitor 10 also acts as a filament heating impedance of the load 12 and a starting voltage application impedance. Before and after lighting the load 12, the resonance characteristics change depending on the presence or absence of the resistance component of the load 12. Load 12
Is designed so that the sharpness of the resonance becomes larger before lighting. A driving circuit 13 alternately switches the switching devices 6 and 7. The switching frequency is, for example, 20 kHz or higher, which is higher than the audio frequency. The drive circuit 13 has feedback means 14 for generating a voltage corresponding to the voltage of the load circuit 8, and the output of the feedback means 14 is supplied to the parallel resonance circuit via the current control means 15. Here, the current control means 15 includes junction-type field effect transistors 16, 1 connected in series with opposite polarities to each other.
7. A resistor 1 connected in series to each of the transistors 16 and 17 and supplying a voltage between both ends to the gate of each of the transistors 16 and 17
8 and 19. The parallel resonance circuit includes a capacitor 20 and an inductor 21 and is provided between the gate and the source of the switching device 6. A winding 22 is magnetically coupled to the inductor 21, and the winding 22 is provided between the gate and the source of another switching device 7.

In this embodiment, the switching devices 6 and 7
Although the illustration and description of the starting circuit for starting are omitted, various types can be appropriately selected and used. Next, the operation of the present embodiment will be described. When the AC power supply 2 is turned on by a switch (not shown), the DC power supply 1
A predetermined DC voltage is generated at both ends of the smoothing capacitor 5.
Here, assuming that the switching device 6 is first turned on, a current flows from the DC power supply device 1 to the load circuit 8 via the drain / source of the switching device 6. The current flowing through the load circuit 8 is controlled by the resonance inductor 9.
And a resonance current by the resonance capacitor 10.
Further, the output of the feedback means 14 is generated by the voltage of the inductor 9 and supplied to the parallel resonance circuit via the current control means 15 to generate a resonance voltage. The switching device 8 is turned on by this resonance voltage, and the switching device 7 is reverse biased. When the resonance voltage of the parallel resonance circuit is inverted, the switching device 6 is turned off, and the switching device 7 is turned off.
Turns on. When the switching device 7 is turned on, a resonance current flows in the load circuit 8 through the switching device 7 in a direction opposite to the previous direction. Even during this period, the return means 14
Is supplied to the parallel resonance circuit via the current control means 15. Therefore, even if the current flowing to the parallel resonance circuit via the current control means 15 is to be increased, the current is suppressed to a certain value or less as shown in FIG. Can be When the current value is suppressed to a certain value or less, the energy of the parallel resonance circuit is suppressed, and the peak value of the resonance voltage (FIG. 2B) is suppressed. As a result, the switching devices 6, 7 can be protected from overvoltage between the control pole and the main pole.

Thereafter, the switching devices 6 and 7 are alternately turned on, and the load circuit 8 supplies a high-frequency voltage to the load 12 in response thereto. The load 12 starts and lights up after the filament is preheated.

Next, a second embodiment of the present invention will be described. FIG. 3 is a circuit diagram showing another embodiment of the present invention.
Note that the same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals and description thereof will be omitted.

In this embodiment, of the pair of voltage-driven switching devices, the switching device 30 is an N-type and the switching device 31 is a P-type, and the respective sources are connected.

The drive circuit 13 'of this embodiment comprises an inductor 32 and a capacitor 3 on the output side of the current control means 15.
3 is provided. The voltage across the capacitor 33 is determined by the
0 and 31 are applied between the gate and the source.

The operation of the present embodiment will be easily understood from the description of FIG. 1 and the above description of the configuration.

In this embodiment, by using N-type and P-type switching devices in combination, the portion corresponding to the output winding 22 can be omitted as compared with that of FIG. It can be downsized. One embodiment of the lighting device of the present invention will be described. FIG. 4 is a partially sectional front view showing an embodiment of the lighting device of the present invention. This embodiment is applied to a so-called bulb-type fluorescent lamp. Reference numeral 40 denotes a lighting fixture main body, which has a base 41, a base 42, and a cover 43. Reference numeral 44 denotes a discharge lamp having a bent discharge path formed by connecting three U-shaped glass bulbs to each other. Is housed in

Reference numeral 45 denotes a discharge lamp lighting device, which is configured by mounting an electronic component 47 on a wiring board 46, and mainly having a base portion 42 with a tall electrical component mounting surface on the base 41 side.
Housed within.

According to the first and second aspects of the present invention, the current value supplied to each switching device by the current control means is suppressed to a predetermined value or less, and is applied between the control pole and the main pole of the switching device. Keep the voltage below a certain value,
Protect the switching device from overvoltage. In addition, since the current control means is used, it is relatively easy to cope with the case where an attempt is made to make an IC, and it is possible to make an IC at a low cost.

According to the third and fourth aspects of the present invention, it is possible to provide a discharge lamp lighting device or a lighting device having the same effects as those of the first and second aspects.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a current and voltage waveform diagram showing the operation of one embodiment of the present invention.

FIG. 3 is a circuit diagram showing a second embodiment of the present invention.

FIG. 4 is a partial cross-sectional front view showing an embodiment of the lighting device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... DC power supply device, 6, 7, 30, 31 ... Switching device, 8 ... Load circuit, 12 ... Load, 13, 13 '... Drive circuit, 15 ... Current control means.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiko Kamada 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo Inside Toshiba Litec Corporation (72) Inventor Hajime Osaki 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo No. Toshiba Litec Corporation F term (reference) 3K072 AA02 AA06 BA03 BB01 BC01 BC03 DB03 DD04 GA02 GB12 GC02 5H007 AA06 BB03 CA02 CB09 CB17 CC07 DA05 DB03 DC02 FA01 FA13

Claims (4)

[Claims] A DC power supply device; a pair of voltage-driven switching devices for inputting a DC voltage of the DC power supply device and alternately turning on and off to switch the DC voltage; and an AC voltage supplied with a switching output of the switching device. And a drive circuit having feedback means for generating a voltage corresponding to an AC voltage supplied to the load, and applying an output of the feedback means to each switching device as an on / off drive voltage. And a current control means provided in the circuit for controlling a current value supplied to each switching device for on / off control to a predetermined value or less. A DC power supply; a pair of voltage-driven switching devices for inputting a DC voltage of the DC power supply and alternately turning on and off to switch the DC voltage; and a resonance inductor and a resonance capacitor. A load circuit that is supplied with a switching output of the switching device to generate a resonance voltage and supplies the resonance voltage to a load; feedback means for generating a voltage corresponding to an AC voltage supplied to the load; A drive circuit that includes a resonance circuit that resonates with the output voltage, and that applies the output of the resonance circuit to each switching device as an on / off drive voltage; a current provided to control the current of the resonance circuit of the drive circuit to a predetermined value or less. A power supply device comprising: control means; 3. A power supply according to claim 1 or 2, and a discharge lamp as a load energized by a load circuit of the power supply.
A discharge lamp lighting device comprising: 4. A lighting device comprising: a lighting fixture main body; a discharge lamp lighting device according to claim 3; and a discharge lamp lit by the discharge lamp lighting device.