JP2000295871A - Power supply unit, lighting device for fluorescent lamp, and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide reduction in size and weight for the whole device by eliminating a winding for a feedback means. SOLUTION: When an N-type FET 5 is turned off, current flowing through a load circuit 9 starts flowing through the path of a load circuit 9, DC power supply unit 1, the parasitic diode of P-type FET 6, and the second circuit element 8. Voltage is generated on both ends of the second circuit element 8 and charges a capacitor 14 through a second rectifying element 16. When the energy in the inductor of the load circuit is lost, current flowing through the parasitic diode of the P-type FET 6 and the voltage on both ends of the second circuit element 8 are also lost. The voltage charged to the capacitor 14 is applied between the gate-source of the P-type FET 6 through the path of the first rectifying element 15, first circuit element 7 and second circuit element 8, thereby turning on the P-type FET 6.

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 having a high frequency generating means, a discharge lamp lighting device, and a lighting device.

2. Description of the Related Art Conventionally, in a power supply device provided with a high frequency generating means, a so-called other type using an oscillation device or the like as a means for turning on / off a switching device for generating a high frequency generally tends to be expensive. .

On the other hand, there is a so-called self-excited type in which a part of its own oscillation output is fed back for switching.
This eliminates the need for a special oscillation device or the like.

[0003]

The feedback means in the self-excited type is usually a current transformer, a feedback winding magnetically coupled to a resonance inductor, a feedback winding wound around an output winding, or the like.
As described above, since the feedback means is a winding, the structure is large, the weight is relatively large, and there is a case where the size and weight of the entire device are greatly restricted. For example, when used as a lighting device for a bulb-type fluorescent lamp, the base part of the bulb-type fluorescent lamp, and a light-transmitting cover that is continuous with the base part and is housed in a cover that needs to be downsized. Need to be as small as possible. In the case where a small size and light weight is required as in the bulb-type fluorescent lamp, it is difficult to cope with a conventional device using a winding component as the feedback means.

An object of the present invention is to provide a power supply device, a discharge lamp lighting device, and a lighting device which can reduce the size and weight of the entire device by eliminating a winding as a feedback means.

[0005]

According to a first aspect of the present invention, there is provided a power supply apparatus comprising: a DC power supply; an N-type FET and a P-type FET connected in series between output terminals of the DC power supply;
First and second circuit elements interposed in series between the FET and the P-type FET to generate a voltage drop at both ends thereof; one of the N-type FET and the P-type FET;
And a load circuit provided in parallel with a series circuit with one of the second circuit elements and including an inductor and a capacitor forming a series resonance circuit; and gate and source of the N-type FET and the P-type FET A capacitor having one end commonly connected to the gate of each FET so that a drive voltage can be supplied to the other of the FETs; and a first capacitor provided between the other end of the capacitor and an intermediate point between the N-type FET and the first circuit element. A circuit for charging the capacitor to one polarity by the voltage of the circuit element is formed, and the drive voltage supply path of the N-type FET is set based on the charging voltage of the other polarity of the capacitor during a period different from the period for charging the capacitor. A first rectifying element to be formed; and a capacitor provided between the other end of the capacitor and a middle point between the P-type FET and the second circuit element. To form a circuit for charging the polarity, P-type FE based on one polarity of the charging voltage of the capacitor in a period different from the period in which charges the capacitor
And a second rectifying element forming a T drive voltage supply path.

In the present invention and the following inventions, unless otherwise specified, each configuration, term, and the like are defined as follows. DC power supply devices that can use various types such as those that input commercial power and perform rectification and rectification smoothing, those that use a low-distortion circuit such as an active filter, those that use the DC power supply itself such as a battery, and the like. It is.

[0007] The term "serial" means that other parts are interposed in the middle of the series itself. The same applies to the parallel operation.

The first and second circuit elements need only generate a voltage drop at both ends.
What does not substantially generate a voltage drop depending on the forward current of the ET or P-type FET can reduce the power loss. Such elements include Zener diodes,
There is a parallel circuit of a diode and a resistor. However, as described above, a voltage drop may be generated at both ends, so that other components can be used.

The connection of one end of the capacitor to the gate of the N-type FET or the P-type FET in common includes both the case where the capacitor is directly connected and the case where the capacitor is connected via a current limiting resistor. Further, a discharge resistor and a constant voltage means may be connected in parallel to the capacitor.

[0010] The load circuit can be configured, for example, to energize the discharge lamp. That is, a discharge lamp can be provided in parallel with the capacitor forming the series resonance circuit. However, the load circuit is not limited to this, and any load circuit may be used. For example, an output transformer may be included in the load circuit, and the output of the output transformer may be rectified and smoothed to supply the DC load.

According to the first aspect of the present invention, there is provided an N-type FET.
When the state shifts from on to off, the N-type FET
The current flowing in the load circuit flows through the path of the load circuit, the DC power supply, the parasitic diode of the P-type FET, and the second circuit element. For this reason, a voltage is generated across the second circuit element, and this voltage charges the capacitor to the other polarity via the second rectifying element.

Next, when the energy of the inductor of the load circuit is lost due to the discharge, the current flowing through the parasitic diode of the P-type FET is lost, and the voltage across the second circuit element is also lost. Therefore, the voltage charged to the other polarity in the capacitor is applied between the gate and the source of the P-type FET via the first rectifying element-the first circuit element-the second circuit element, and the P-type FET is turned on. I do. When the P-type FET is turned on, a current flows from the DC power supply to the load circuit, the second circuit element, the P-type FET, and the DC power supply.

Next, when the P-type FET shifts from on to off, the current flowing through the P-type FET becomes the first current.
Flows through the load circuit via the circuit element of the above and the parasitic diode of the N-type FET. For this reason, a voltage is generated across the first circuit element, and this voltage charges the capacitor to one polarity through the first rectifier.

Further, when the energy of the inductor of the load circuit is lost due to the discharge, the current flowing through the parasitic diode of the N-type FET disappears, and the voltage across the first circuit element also disappears. The voltage charged to the capacitor in one polarity is applied between the gate and source of the N-type FET through the second rectifier element, the first circuit element, and the second circuit element. Turn on. By turning on the N-type FET,
A current flows through the load circuit via the N-type FET and the first circuit element.

Thereafter, the above operation is repeated, and a high frequency voltage of, for example, several tens KHz to several hundred KHz is generated in the load circuit. The N-type FET and the P-type FET are so-called self-excited oscillations, but since no winding parts are used as feedback means, the whole device can be reduced in size and weight.

According to a second aspect of the present invention, in the power supply apparatus of the first aspect, the first and second circuit elements are Zener diodes.

According to a second aspect of the present invention, there is substantially no voltage drop of the first or second circuit element during a period when the N-type FET or the P-type FET is on and a forward current flows. Therefore, power loss can be reduced. N-type FET or P
During the period when the FET is off and current flows through the parasitic diode, a voltage corresponding to the Zener voltage of the first or second circuit element is generated, so that the capacitor can be charged.

According to a third aspect of the present invention, in the power supply device of the first aspect, the first and second circuit elements are a parallel circuit of a diode and a resistor.

The third aspect of the invention has the same function as the second aspect of the invention.

According to a fourth aspect of the present invention, there is provided a discharge lamp lighting device according to the first to third aspects, wherein the discharge lamp is energized as a load of a load circuit.

The invention described in claim 4 can provide a discharge lamp lighting device that can be reduced in size and weight, and is suitably applied to, for example, a bulb-type fluorescent lamp.

According to a fifth aspect of the present invention, there is provided a lighting apparatus comprising: a lighting fixture body; a discharge lamp lighting apparatus according to the fourth aspect; and a discharge lamp provided in the lighting fixture body and energized by the discharge lamp lighting apparatus. It is characterized by having.

The lighting device to which the present invention is applied may be any lighting device such as a general lighting device, an indicator lamp, and an OA device. Also, a so-called bulb-type fluorescent lamp may be used.

The illuminating device of the present invention is an illuminating device having the same operation as the fourth aspect of the present invention.

[0025]

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

FIG. 1 is a circuit diagram showing an embodiment of the present invention. Reference numeral 1 denotes a DC power supply. This DC power supply 1
Has a rectifier 3 connected to an AC power supply 2 and a smoothing capacitor 4 provided between output terminals of the rectifier 3. Although not shown, a current fuse, a high-frequency cut filter, and the like can be appropriately provided on the input side of the rectifier 3.

Reference numeral 5 denotes an N-type FET, and reference numeral 6 denotes a P-type FET, which are connected in series to each other, and are provided between output terminals of the DC power supply 1. The gates of these FETs 5 and 6 are commonly connected. Reference numerals 7 and 8 denote first and second circuit elements, for example, zener diodes, which are connected in series between the N-type FET 5 and the P-type FET 6.

The N-type FET 5 and the first circuit element 7
A load circuit 9 is provided in parallel with the series circuit of. The load circuit 9 is an inductor 1 forming a series resonance circuit.
0 and a capacitor 11. Reference numeral 12 denotes a DC cut capacitor. The load circuit 9 of the present embodiment energizes the discharge lamp 13, and the discharge lamp 13 which is a fluorescent lamp is connected in parallel with the capacitor 11. In the case of the present embodiment, the inductor 10 also has a current limiting impedance function of the discharge lamp 13.

Reference numeral 14 denotes a capacitor for supplying a drive voltage to each of the FETs 5 and 6, one end of which is connected to the gate of each of the FETs 5 and 6. The capacitor 14 is connected to the first circuit element 7 -the capacitor 14 -the first rectifier element 15 -the first circuit element 7 depending on the voltage of the first circuit element 7.
Polarity (the polarity where the upper end is + in Fig. 1)
Is charged.

Also, depending on the voltage of the second circuit element 8, the capacitor 14 has the other polarity (lower end in FIG. 1) through the path of the second circuit element 8, the second rectifier element 16, and the second circuit element 8. (Positive polarity on the side).

Reference numeral 17 denotes a current limiting resistor, and reference numeral 18 denotes a discharging resistor. Although the starting circuit is not shown, a known circuit or the like can be appropriately 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 generates a predetermined DC voltage across the smoothing capacitor 4. One of the FETs is turned on by a starting circuit (not shown) after the voltage between both ends of the smoothing capacitor 4 sufficiently rises or after the voltage has sufficiently risen. Here, N
The following description is based on the assumption that the FET 5 is turned on. N-type FET
When the switch 5 is turned on, a resonance current flows through the load circuit 9 using the charged capacitor 11 as a power supply via a starting circuit (not shown).

In response to the inversion of the resonance voltage of the load circuit 9,
When the N-type FET 5 shifts from the ON state to the OFF state, the current flowing in the N-type FET 5 and the load circuit 9 is changed by the energy of the inductor 10 to the load circuit 9-the smoothing capacitor 4-P of the DC power supply 1. The current flows through the path between the parasitic diode of the FET 6 and the second circuit element 8. Therefore, a voltage is generated across the second circuit element 8, and the voltage charges the capacitor 14 to the other polarity via the second rectifying element 16.

Next, when the energy of the inductor 10 is completely discharged, the current flowing through the parasitic diode of the P-type FET 6 disappears, and the voltage across the second circuit element 8 also disappears. Therefore, the voltage charged to the other polarity in the capacitor 14 is applied between the gate and the source of the P-type FET 6 via the first rectifier 15 -the first circuit element 7 -the second circuit element 8. The FET 6 is turned on. When the P-type FET 6 is turned on, a current flows from the DC power supply 1 to the load circuit 9, the second circuit element 8, the P-type FET 6, and the DC power supply 1.

Next, when the P-type FET 6 shifts from ON to OFF, the current flowing through the P-type FET 6 by the energy of the inductor 10 passes through the first circuit element 7 and the parasitic diode of the N-type FET 5. Load circuit 9
To flow to. For this reason, a voltage is generated across the first circuit element 7, and the voltage charges the capacitor 14 to one polarity via the first rectifying element 15.

Further, when the energy of the inductor 10 is completely discharged, the current flowing through the parasitic diode of the N-type FET 5 disappears, and the voltage across the first circuit element 7 also disappears. The voltage charged in the capacitor 14 to one polarity is
This time, the voltage is applied between the gate and the source of the N-type FET 5 through the second rectifying element 16 -the first circuit element 7 -the second circuit element 8 to turn on the N-type FET 5. When the N-type FET 5 is turned on, a current flows through the load circuit 9 via the N-type FET 5 and the first circuit element 7.

Thereafter, the above operation is repeated, and the load circuit 9
Generates a high frequency voltage of several tens KHz to several hundred KHz, for example.

Next, a second embodiment of the present invention will be described. FIG.
FIG. 3 is a circuit diagram showing a second embodiment. Parts that are the same as or correspond to those in FIG.
The first and second circuit elements 20 and 21 of the present embodiment are formed of a parallel circuit of diodes 22 and 23 and resistors 24 and 25, respectively. Further, a series circuit of a pair of zener diodes 26 and 27 is connected in parallel to the capacitor 14 so that the voltage of the capacitor 14 and the gate-source voltage of each of the FETs 5 and 6 are stabilized. Furthermore, each F
Current limiting resistors 28 and 29 are provided corresponding to ET5 and ET.

The operation of the present embodiment can be easily understood by referring to the description so far, and the description is omitted.

An embodiment of the lighting device of the present invention will be described. FIG. 3 is a partial cross-sectional front view schematically 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 30 denotes a lighting fixture main body, which has a base 31, a base 32, and a cover 33. 34 is a fluorescent lamp as a discharge lamp,
The three U-shaped bulbs are interconnected to form one discharge space.

Reference numeral 35 denotes a discharge lamp lighting device, which is constructed by mounting an electronic component 37 on a wiring board 36, and housed and supported mainly in a base 31 and a base 32.
The discharge lamp lighting device 35 is that of the above-described embodiment.

Although the wiring is not shown in FIG. 3, necessary wiring is provided.

[0043]

According to the first to third aspects of the present invention, a capacitor is charged by using a current flowing through a parasitic diode of an N-type or P-type FET, and each FET is driven by the charge of the capacitor. Therefore, it is possible to eliminate the necessity of a winding component as a feedback unit, and to provide a power supply device capable of reducing the size and weight of the entire device.

The invention described in claim 4 is the first to third aspects of the present invention.
It is possible to provide a discharge lamp lighting device having the same effect as the invention described in any one of the above.

The invention according to claim 5 can provide a lighting device having the same effect.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a partial cross-sectional front view showing a simplified embodiment of the lighting device of the present invention.

[Explanation of symbols]

1: DC power supply device, 5: N-type FET, 6: P-type FET,
7, 20: first circuit element, 8, 21: second circuit element, 9: load circuit, 14: capacitor, 15: first rectifier element, 16: second rectifier element, 30: lighting fixture body ,
34: discharge lamp, 35: discharge lamp lighting device.

Claims (5)

[Claims] An N-type FET and a P-type FE connected in series between output terminals of a DC power supply.
T; first and second circuit elements interposed in series between the N-type FET and the P-type FET and generating voltage drops at both ends thereof; one of the N-type FET and the P-type FET; A load circuit provided in parallel with a series circuit with one of the second circuit elements and including an inductor and a capacitor forming a series resonance circuit; and a gate / source of an N-type FET and a P-type FET. A capacitor having one end commonly connected to the gate of each FET so as to supply a drive voltage; the other end of the capacitor, and an N-type FET
And a circuit provided between the first circuit element and the middle of the first circuit element to charge the capacitor to one polarity by the voltage of the first circuit element. A first rectifying element for forming a drive voltage supply path for the N-type FET based on the charging voltage of the other polarity; a first rectifying element provided between the other end of the capacitor and an intermediate point between the P-type FET and the second circuit element; And forming a circuit for charging the capacitor to the other polarity by the voltage of the second circuit element, and supplying a drive voltage for the P-type FET based on the charging voltage of one polarity of the capacitor during a period different from the period for charging the capacitor. And a second rectifying element forming a path. 2. The power supply device according to claim 1, wherein said first and second circuit elements are Zener diodes. 3. The power supply device according to claim 1, wherein said first and second circuit elements comprise a parallel circuit of a resistor and a diode. 4. A discharge lamp lighting device characterized in that a discharge lamp is energized as a load of a load circuit of the power supply device according to any one of claims 1 to 3. 5. A discharge lamp lighting device according to claim 4, comprising: a lighting fixture main body; a discharge lamp provided in the lighting fixture main body and energized by the discharge lamp lighting device. Lighting equipment.